Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates generally to numerically
controlled machine tools having an automatic tool
changer thereon and, more specifically, to a numeric-
ally controlled automatic tool changing machining
center having a bar-t~pe spindle.
In the past, machine tools have been constructed
with automatic tool changers capable of accomrnoda-ting
either single shank toolholders or large multiple
spindle toolheads weighing as much as 500 kgs. (1,000
lbs~) but not both. Machine tools having automatic
tool changers thereon capable of e~changing single
shank toolholders are usually fabricated with the tool
storage magazine mounted on either the machine tool
column or on the machine tool spindlehead. Such an
arrangement precludes accommodation of large multiple
spindle toolheads since the storage of one or more
heavy multiple spindle toolheads in a spindlehead-
mounted or column-mounted tool storage magazine will
likely pl~ce an undue strain on the upright, tending to
adversel~ affect machine tool accuracy. On the other
hand, machine tool automa-tic tool changers which are
designed to exchange large multiple spindle toolheads
are typically unable, because of the large size and
bulk of the tool changer mechanism, to acco~nodate
smaller single shank toolholders.
In an attempt to overcorne this difficulty, the
machine tool and automatic tool changer therefore
described and claimed in U.S. Patent 4,288,909 issued
on September 15, 1981 was invented. The autornatic tool
changer described and claimed in this patent comprises
a tool storage magazine, which, together with the
machine tool upright, is mounted on a saddle that is
slidably mounted on the machine tool bed so that the
upright and machine tool column move in unison. The
upright slidably supports a spindlehead in which is
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rotatably journaled a spindle for carrying a selected
one of the multiple spindle toolheads and single
toolholders which are vertically stored in the tool
storage magazine. To accomplish a tool exchange, a
toolholder or multiple spindle toolhead stored in the
tool storage magazine is transferred from the -tool
storage magazine by a first tool gripper to a tilt unit
which tilts the tool 90 to enable a double ended tool
changer arm mounted on the saddle to exchange the tool
held in the tilt unit with the tool then engaged in the
spindle. A multiple spindle toolhead transferred from
the tool storage magazine to the spindle in this manner
is secured to the spindle head by a breech lock mechanism
comprised of a plurality of threaded studs each extending
rearwardly from the toolhead into a complementary
threaded collar in the machine tool spindle head adjacent
to the spindle. Each threaded collar is rotatably driven
by a ball screw to engage its complementary stud on -the
toolhead so as to urge the toolhead against the spindle.
While the above-described machine tool is capable of
accommodating both single toolholders and multiple
spindle toolheads, thus overcoming the disadvantages of
the aforementioned prior art automatic tool changers, the
previously invented automatic tool changer necessitates a
relatively complicated breech lock arrangement for secur-
ing multiple spindle toolheads against the machine tool to
prevent rotation of the toolhead body when the toolhead
input shank is driven by the spindle. In contrast, my
present invention concerns an automatic tool changing
machining center whose spindle has a bar concentric
therein for extension from the spindle to engage a tool-
holder or multiple spindle toolhead. The har is retract-
able into the spindle for urging a large single toolholder,
when so engaged by the spindle bar, against the spindle
nose and for urging a multiple spindle toolhead, when so
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engaged by the spindle bar, against the machine tool so
that locating pins extending rearwardly from the multiple
spindle toolhead body engage complementary locating cones
secured on the machine tool thereby securing the multiple
spindle toolhead body against rotation~
In accordance with one aspect of the invention there
is provided a method of securing a toolhead having a
stationary housing supporting a rotary cutter to a machine
tool spindle for performing a machining operation with the cutter;
the method comprises extending a spindle bar axially of the
spindle, operating a tool change mechanism for transferring
the toolhead from a tool storage magazine to;the extending
spindle bar~ The toolhead is locked to the spindle bar for
rotation therewith, and the spindle bar is retracted for
drawing the stationary housing of the toolhead against the
-face of the machine tool for rigidly supporting the tool-
head. The movement of the toolhead toward the face of -the
machine tool is caused to engage a lock for locking the
stationary housing oE the toolhead to the machine tool
while the rotaty cutter of the toolhead is being driven
by the rotating spindle bar of the machine tool.
In accordance with another aspect of the invention
` there is provided a machine tool adapted to operate tool-
heads in which the cutting tool is rotatahly supported by
a stationary housing having a driver which may he rotated
to produce rotation of the cutting tool. The machine tool
includes a frame presenting a front face and a bar-type
spindle rotatably supported by the frame and movable
; axially through the front face so that its front end can
be extended forwardly of the front face~ ~ttaching means
in -the spindle firmly attaches a toolhead to its forward
end for rotation therewith. Actuating means for shifting
the spindle in its axial movement of its forward posi-
tion for receiving a toolhead and a rearward operating
position, a flat surface on the head in position to
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engage the front face of the frame for supporting the
toolhead when it is moved to its operating position.
Securing means fixed to the frame adjacent to the
spindle for engagement with complementary securing
means on the housing of the toolhead so that movement
of the toolhead to its operating position moves the
securing means on the toolhead into engagement with
the complementary securing means on the frame for
securing the toolhead against the front face of the
frame while the spindle is rotating the driver to
perform a machining operation.
In accordance with a preferred embodiment of the
invention, an improved numerically controlled machining
center and automatic tool changer therefor comprises a
bed on which a saddle is slidably mounted for movement on
the bed along a first pathO The saddle slidably supports
a column or upright which is movable on the saddle along
a path perpendicular to the path of saddle movement on
the bed. In addition, the saddle also slidably supports
an automatic tool changer so
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that the automatic tool changer and upright move in unison
with the saddle. On the upright there is slidably mounted the
spindlehead whlch moves vertically on the upright along a path
perpendicular to both the path of saddle movement on the bed
and upright movement on the saddle. Rotatably journaled into
the spindlehead is a rotary-driven cutting tool-carrying
spindle concentric within which is a spindle bar which rotates
co-jointly with the spindle. Means are provided, in the form
of a hydraulic cylinder, for urging the spindle bar outwardly
to enable a tool gripper located at the end of the spindle bar
distal from the spindlehead to engage either a single tool-
holder or multiple spindle toolhead transferred thereto from
the tool storage magazine by the tool changer. After a large
single toolholder is engaged by the spindle bar tool gripper,
the spindle bar is retracted in the spindle to urge the large
single toolhoLder against the spindle nose to provide addition-
al support for the toolholder. Following extension of the
spindle bar to engage a multiple spindle toolhead, the spindle
bar is retracted into the spindle to urge the multiple spindle
toolhead agains~ the machine tool so that locating pins extend-
ing rearwardly from the toolhead engage complementary locating
cones on the machine tool, respectively. In this way, the
multiple spindle toolhead body is prevented from rotating.
The automatic tool changer of the present invention comprises
a tool storage magazine carried by the saddle for vertically
storing the single toolholders and multiple spindle toolheads
and includes a tool transfer mechanism having a double ended
tool transfer arm movable along the saddle and pivotal about a
pair of mutually perpendicular paths for transferring tool-
holders and multiple spindle toolheads between the spindle bar
and the tool storage magazine. The tool storage mayazine can
be fixedlv mounted on the saddle or can be removably secured
on the saddle so as to advantageously permit exchange of an
entire tool storage magazine, thereby tremendously increasing
machine tool flexibility.
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BRIEE DESCRIPTION OF THE DRAWINGS
The features of this invention believed to be novel are
set forth in the appended claims. The invention itself, both
as to organization and method of operation together with
further objects and advantages thereof, may best be understood
by reference to the drawings in which:
Fig. 1 is a frontal view of the automatic tool changing
machining center of the present invention;
Fig. 2 is a top or plan view of the automatic tool chang
ing machining center in Eig. 1;
Fig. 3 is an end view of the automatic tool changing
machining center of Fig. 2 taken along lines 3-3 thereof;
Fig. 4 is a cross sectional view of a portion of the
automatic tool changing machining center of Fig. 2 taken along
lines 4-4 thereof;
Fig. 5 is an enlarged sectional view of the spindle bar
tool gripping mechanism comprising a portion of the automatic
tool changing machining center depicted in Fig. 4;
Fig. 6 is an end view of the spindlehead of the machining
center of Fig. 1 taken along lines 6-6 of Fig. 4;
Fig. 7 is a cross sectional view of the draw rod driver
motor and clutch mechanism of the machining center of the
present invention taken along lines 7-7 of Eig. 6;
Fig. 8 is an enlarged sectional view of a portion of the
draw rod driver motor arrangement depicted in Fig. 7;
Fig. 9 is a cross sectional view of the quill shot pin
mechanism of the automatic tool changing machining center of
Fig. 1 taken along lines 9-9 of Fig. 5;
Fig. 10 is a sectional view of the spindle keylock mechan
ism of the automatic tool changing machining center taken
along lines 10-10 of Fig. 6;
Fig. ll is an enlarged frontal view of the automatic tool
changing machining center o Fig. 1;
Fig. 12 is a cross sectional view of one of a chain
supporting sheaves of Fig. 11 taken along lines 12-12 thereof;
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Fig. 13 is an enlarged frontal view of a portion of the
tool transfer arm carrier of the automatic tool changing
machining center of the present invention;
Fig. 14 i5 an enlarged rearward view of a portion of the
tool transfer arm carrier of the automatic tool changing
machining center of the present invention;
Fig. 15 is an enlarged side view of a portion of the tool
transfer arm carrier of the automatic tool changing machining
center of t~e present invention;
Fig. 16 is a cross sectional view taken along lines 16-16
of Fig. 13 illustrating the internal details of the tool
transer arm carrier;
Fig. 17 is an enlarged frontal view of the tool transfer
arm comprising a portion of the tool transfer mechanism;
Fig. 18 is a cross sectional view of the tool transfer
arm of Fig. 17 taken along lines 18-18 thereof;
Fig. 19 is a frontal view of the stop plate attached to
the rearward end of the tool transfer arm;
Fig. 20a through 20g illustrate, in sequential fashion,
the position of the tool transfer arm duriny each respective
step of a tool change cycle;
Fig. 21 is an enlarged cross sectional view taken along
lines 21-21 of Fig. 2 illustrating how a multiple spindle
toolhead seats itself against a machine tool when the spindle
bar engaging the multiple spindle toolhead is retracted into
the spindle;
Fig. 22 is a frontal view of an alternate embodiment of
the automatic tool changing machining center of the invention;
and
Eig. 23 is a top or plan view of the automatic tool
'changing machining center of Fig. 22.
DETAILED DESCRIPTION OF T~E PREFERRED EMBODIMENT
Figs. 1, 2 and 3 illustrate in elevation the front,
plan and side views, respectively, of an improved machining
center 10 having an automatic tool changer thereon. Machining
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center 10 comprises a bed 12 having three ways 14a, 14b and
14c (Figs. 2 and 3) fastened ther~on in spaced apart parallel-
ism. A saddle 16 is slidably mounted on the ways by gibs 18
(Fig. 3) for movement on bed 12 along the ways parallel to a
first path hereinafter designated as the X axis (Figs. 1 and
2). Conventional means (not sho~n), typically taking the form
of a ball nut fastened to the underside of the saddle, a ball
screw rotatably journaled in the bed so as to be in threaded
engagement with the ball nut and a servo motor for rotatably
driving the ball screw under command of the machine tool
control system ~not shown), are provided for precisely posi-
tioning saddle 16 on bed 12 along the X axis. Saddle 16 has a
pair of parallel, spaced apart ways 20 (Figs. l and ~) fastened
thereon so as to be perpendicular to each of ways 14a, 14b and
14c on bed 12. A column or upright 22 is slidably mounted on
ways 20 by gibs 24 (Fig. l) for movement on the ways across
the saddle along a second path hereinafter designated as the Z
axis (Figs. 2 and 33, the Z axis being perpendicular to the X
axis. Conventional means (not shown), typically taking the
form of a ball nut fastened to the underside of upright 22, a
ball screw journaled in the saddle in threaded engagement with
the ball nut and a servo motor under command of the machine
tool control system for rotatably driving the ball screw, are
providad for precisely positioning the upright 22 along the Z
axis.
Fastened to the side of column 22 is a pair of parallel
spaced apart ways 26 (Figs. 2 and 3) which extend vertically
on the upriqht along a third path hereinafter designated as
the Y axis (Figs. 1 and 3) which is mutually perpendicular to
each of the X and Z axes. Ways 26 slidably support a spindle-
head 28 which is secured to the ways by gibs 30 (Fig. 2) for
movement on the ways along the Y axis. Conventional means,
taking the form of a ball nut (not shown) fastened to the
spindlehead, a ball screw rotatably journaled in the upright
for threaded engagement wit~ the ball nut and a servo motor 32
(Eigs. 1 and 3) for rotatably driving the ball nut under
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command of the machine tool control system, are provided for
precisely positioning spindlehead 28 along ways 26.
Spindlehead 28 has a cutting tool carrying spindle 34
horizontally journaled in the front face thereo~ for rotation
about axis parallel to the Z axis (Figs. 2 and 3). Spindle 34
is rotatably driven through 2 gear train within the spindlehead
(described in greater detail with respect to Fig. 4) from a
spindle drive motor 36 (Figs. 2 and 3~ attached to the rearward
end of the spindlehead. Concentric within spindle 34 is a
spindle bar 38 which rotates co-jointly with the spindle when
the spindle is driven by spindle drive motor 36. As will be
seen in greater detail hereinafter, spindle bar 38 is laterally
movable relative to the spindle along their common axis so as
to enable the spindle bar to be extended forwardly from the
spindle to engage a single toolholder or multiple spindle
toolhead and to be retracted into the spindle to urge a tool-
holder, when engaged by the spindle bar, against the spindle
nose and to urge a multiple spindle toolhead, wh~n so enqaged
by the spindle bar, against the machine tool spindlehead.
Saddle 16, in addition to supporting ways 20, also sup-
ports a second set of ways 40 (Eig. 2) which are secured
thereon so as to be in spaced apart parallelism with each
other, with each of ways 40 beiny perpendicular to each of
ways 20. Ways 40 slidably support an automatic tool changar
42, which, in the presently preferred embodiment, comprises a
platform 43 (Figs. 1 and 2) slidably supported on ways 40 for
movement thereon to and from spindlehead 28 alon~ a path
parallel to the X axis. Conventional means (not shown~,
typically taking the form of a hydraulic cylinder, is coupled
between platform 43 and saddle 16 and is pressurized, respon-
sive to commands from the machine tool control system, to
displace platorm 43 along ways 40. Platform 43 has a pair of
parallel spaced apart ways 44 (Fig. 2) fastened theraon with
each of ways 44 bein~ perpendicular to ways 40 on saddle 16.
Ways 44 slidably support a tool change tower 46 (Figs. 1 and
2) which is fastened to the ways by roller gibs 47 (Fig. 1).
Conventional means (not shown), typically taking the form of a
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hydraulic cylinder, is fastened between tower 46 and platform
43 and, when pressurized in response to commands of the machine
tool control system, displaces tower 46 along ways 44 on
platform 43 between a forward and rearward position on saddla
16.
Tower 46 has a pair of parallel spaced apart ways 48
(Figs. 1 and 2) secured to the side of the tower aciny upright
22. A tool chanyer arm carrier 50 is slidably secured to ways
48 by roller gibs 51 (Fig. 2) so as to be movable therealong.
Conventional means in the form of a ball nut (not shown)
fastened to the side of the tool change arm carrier adjacent
to tower 46, a ball screw ~not shown) rotatably journaled in
tower 46 in threaded engagement with the ball nut, and a servo
motor 52 secured to the top of the tower or rotatably driving
the kall screw under command of the machine tool control
system, are provided for positioning the tool change arm carrier
along the tower. A counterbalancing mechanism (described in
greater detail with respect to Figs. 11 and 12) counterbalances
the tool transfer arm carrier as it moves along ways 48 on
tower 46.
Tool transfer arm carrier 50 has a pivot 53 (Fig. 2)
journaled therein for rotation about an axis parallel to the X
axis. Conventional means taking the form of a rotary hydraulic
actuator 54 (illustrated in Fig. 11) are provided for rotating
pivot 53 about its axis under command of the machine -tool
control system. A housing 55 (Fig. 2) is secured to pivot 53
so as to rotate co~jointly therewith about an axis parallel to
the X axis. Housing 55 has a pivot 56 journaled therein for
rotation about an axis perpendicular to the axis of housing 55
rotation. Pivot 56 is rotated under command of the machine
tool control system by conventional means, typically taking
the form of a rotary hydraulic actuator described in greater
detail hereinafter.
A double ended tool change arm 57 (described in detail
with respect to Figs. 17 and 18) is secured to pivot 56 for
co-joint rotation therewith. Tool change arm 57 has a tool
gripper at each end thereo, each of the tool grippers being
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operative to engage the shank of a single toolholder 58 (Fig.
1) or a multiple spindle toolhead 59 (Fig. 1) which are stored
in a tool storaye magazine 60 secured to saddle 16. In the
presently preferred embodiment, tool storage magazine 6G
includes a vertically extending shaft 61 which is rotatably
journaled in saddle 16 for rotation about an axis paraliel to
the Y axis (Fig. 1). At least one tool storage disk 62 is
coaxially secured to shaft 61 for co~joint rotation therewith.
Preferably, three tool storage disks 62 are coaxially secured
to shaft 61 in parallel spaced apart relationship as illus-
trated in Figs. 1 and 3. Each tool storage disk has a plural-
ity of vertically disposed tool receiving sockets 64 (Figs. 2)
therein, the tool receiving sockets being disposed within the
disk adjacent to the periphery thereof for vertically storing
single toolholders and multiple spindle toolheads. Means (not
shown) typically taking the form of a well known servo drive
motor, are provided or precisely rotating shaft 61 about its
axis in accordance with commands from the machine tool control
system to locate one of tool receiving sockets 64 of each of
tool storage disks 62 in a ready position opposite to the tool
change arm to enable transfer of the tool to the spindle bar
by tool change arm 57.
As illustrated in Fig. 4, which is a cross sectional view
of spindlehead 28 taken along lines 4-4 of Fig. 2, spindle
drive motor 36 is fastened to the rear (right-hand end) of
spindlehead 28 by bolts 70 (only one of which is shown) so
that shaft 71 of the spindle drive motor sxtends into the
spindlehead through a passage in the rear spindlehead wall
parallel to spindle 34 and spindle bar 38. A shaft 72 is
journaled through a pair of interior spindlehead walls 75a and
75b by bearings 76a and 76b, respectively, so as to be coaxial
with shaft 71 of the spindle drive motor. A universal coupling
78 couples shaft 71 to shaft 72 so that when spindle drive
motor 36 is energized by the machine tool control system,
shaft 72 rotates co-jointly with spindle drive motor shaft 71.
Fixed on shaft 72 is a pinion gear 80 which is dimen-
sioned complementary to, for meshing engagement wlth a gear 82
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keyed on a shaft 84 journaled through spindle walls 75a and
75b by bearings 86a and 86b, respectively, so as to be paral-
lel to shaft 72. Two other gears ~8 and 90, respactively, are
keyed on shat 84 in spaced apart parallelism with gear 82.
Each of gears 88 and 90 is dimensioned complementary to, for
meshing engagament with a separate one of gear members 92a and
92b of a cluster gear 92 which is in splined engagement with
a shaft 94 journaled at each of its ends into spindlehead wall
7Sb and the forward end of spindlehead 28, respectively, by a
separate one of bearings 96a and 96b, respectively. A third
bearing 96c rotatably journals the medial portion of shaft 94
into wall 75a. Gear member 92a of cluster gear 92 has a
shifting collar 98 integrated to its rearward face. Shifting
collar 98 has a channel inscribed about the periphery thereof
for engaging the tines o a shifter fork (not shown~ which is
connected to a three position hydraulically actuated shifter
cylinder (not shown) that is controlled by the machine tool
control system. By appropriately pressurizing tha hydraulic-
ally actuated shifting cylinder, cluster gear g2 may be shifted
from its central position as illustrated in Fig. 4 either
rightwardly or leftwardly along shaft 94 to bring one of gear
members 92a and 92b, respectively, into meshing engagement
with a corresponding one of gears 88 and 90, respectively,
keyed on shaft 94. In practice, gears ~8 and 90 are dimen-
sioned larger and smaller, respectively, than each of cluster
gear members 92a and 92b, respectively, so that shaft 94 may
be driven from shaft 84 at a speed faster than or slower than
rotational speed o shaft 84 when cluster gear is biased
rightwardly and leftwardly, respectively, from its central
most position.
A second cluster gear 100, having a pair of gear members
lOOa and lOOb, is in splined engagement with shaft 94 between
wall 75a and the forward or leftward end of spindlehead 28.
Each of cluster gear members lOOa and lOOb is dimensioned
complementary to, for meshing engagement with, a separate one
of gears 102 and 104 which are keyed on spindle 34 in spaced
apart parallelism. A shifter collar 106 ls integrated to the
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rearward or right-han~ ~ace of cluster gear member lOOa. The
shifter collar has a groove inscribed about the periphery
thereof for engaging the tines of a shifter fork (not shown3
which is connected to the shaft of a three-position hydraulic-
ally actuated shifting cylinder (not shown) under the control
of the machine tool control syste~. By appropriate prassuri-
zation of the hydraul~cally actuated shifting cylinder, cluster
gear 100 may be shifting along shaft 94 rightwardly or left-
wardly from its central most position illustrated in Fig. 4 to
effect meshing engagement of a separate one of cluster gear
members lOOa and lOOb with a separate one of gears 102 and
104, respectively. In practice, cluster gear members lOOa and
lOOb are each dimensioned larger and smaller than qears 102
and 104, respectively, so that when cluster gear lOOa is
shifted rightwardly and leftwardly from its central most
position, spindle 34 can be driven from shaft 94 at a speed
greater than or less than, respectively, the rotational speed
of shaft 94. Since shaft 94 can itself be driven at two
different speeds ~rom shaft 84 by appropriate shifting of
cluster gear 92, the shifting of cluster gears 92 and 100
permits the ratio of the rotational speed of spindle 34 to the
rotation speed of spindle motor drive shaft 71 to take on any
one of four separate values.
In the presently preferred embodiment, spindle 34 is
configured of an elonyate sleeve or collar which extends into
the spindlehead parallel to the shafts 94 and 84 through a
bore in an annular projection 107 which extends outwardly from
the forward end of the spindlehead. A pair of bearings 108a
and 108b are each carried on the spindle at forward (leftward)
end of the spindle and a short distance rearwardly therefrom,
respectively, for journaling the spindle into the bore through
annular housing 107. Spindle bearing 108a is urged against a
shoulder on the spindle by a bearing cap 110 having a bore
therethrough dimensioned to receive the spindle. Bearing cap
110 is removably secured to the forward face of projection 107
by bolts 112 (only one of which is shown) to overlie the bore
therethrough thereby permitting easy access to the bearing.
1216kl4
13-
Bearing 108b is carried on the spindle between a spindle
shoulder and a nut 113 in threaded engagement with the spindle
to urge the bearing against the shoulder. Spindl~ 34 carries
a third bearing 108c adjacent to rearward spindle end for
journaling the spindle through spindlehead wall 75a. A nut
114 in threaded engagement with the rearward end of the spindle
urges bearing 108c against a keylock disk 115 carried on the
spindle between gear 102 and spindlehead wall 75a. As will be
described in greater detail hereinafter, keylock disk 116,
when engaged by a plunger, described hereinater with respect
to Fig. lO, operates to lock the spindle in a predetermined
an~ular orientation.
Spindle bar 38, which is concentric within spindle 34, is
keyed to the spindle by a key 118 which is radially embedded
into the periphery of spindle bar 38 so as to extend along the
axis of the bar for mating engagement with a complementary
keyway inscribed axially in the bore of spindle 34. Spindle
bar 38, by virtue of its being keyed to spindle 34, can be
extended from or retracted into the spindle while rotating
co-jointly with the spindle. The mechanism for axially reci-
procating the spindle bar within the spindle includes a yoke
120 which is rotatably journaled about the rearward spindle
bar end in a manner described hereinafter. A bolt 121 fastens
the end of the yoke to the shaft of a hydraulic cylinder 122
which is secured to the rearward end of the spindlehead so
that its shaft extends into the spindlehead parallel to the
spindle bar. When cylinder 122 is pressuriæed responsive to a
command from the machine tool control system to extend the
cylinder shaft from the cylinder, spindle bar 38, by virtue of
its bein~ linked to the shaft of cylinder 122 by yoke 120, is
thus forced outwardly from spindlehead 28. Conversely, when
cylinder 122 is pressurized to retract the cylinder shaft into
the cylinder, spindle bar 38 is thus retracted into the spindle-
head.
To assure that there is no radial play between spindle
bar 38 and spindle 34, spindle 34 has a counter bore in each
end thereo which is dimensioned to receive a separate one of
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a pair of tapered bushing sets 123a and 123b, respectively,
which are each carried on the spindle bar. Each tapered
bushing set is urged into the counter bore in a corresponding
one of the ends of the spindle by a separate one of bearing
caps 124a and 124b, respectively, which each have a bore
therethrough dimensioned to receive spindle bar 38. Bolts 126
detachably secure each of bearing caps 124a and 124b to the
rearward and forward ends of the spindle, respectively, so
that each of the bearing caps overlies the counter bore in a
separate one of the rearward and forward ends of the spindle,
raspectively.
Spindle bar 38 is fabricated with an axial bora there-
through which is dimensioned to receive a draw rod 128. Draw
bar 128 e~tends rearwardly beyond the spindle bar into a quill
130 slidably mounted within a coaxial quill sleeve 132 fastened
to the rearward end of spindlehead 28 by bolts 133 (only one
of which is shown~. Quill 130 houses the mechanism (described
in greater detail hereinafter with respect to Fig. 7) which
reciprocates draw rod 128 rearwardly and forwardly to urge the
shank of a single toolholder or multiple spindle toolhead into
engagement with, or to disengage tha shank of a sinqle tool-
holder or multiple spindlehead from the tool receiving socket
129 in the forward end of the spindle bar, respectively.
The details of how draw rod 128, when it is reciprocated
rearwardly and forwardly, operates to engage a toolholder or
multiple spindle toolhead shank in the tool receiving spindle
bar socket, and to disenqage it therefrom, re~pectively, may
be seen more clearly by reerence to Fig. 5 which is an en-
larged view of the forward end o spindle bar 38. As illus-
trated, draw rod 128 has a bore in the forward end thereof
which is threaded for mating engagement with the threads on
the rearward end of a collet 134. Collet 134 has a plurality
of forwardly extending tines 136 (only two of which are shown)
for engaging the retention Xnob 138 extending rearwardly from
the shank 139 of the single toolholder or multiple spindle
toolhead then seated in tool receiving socket 129 in the
~orward end of spindle bar 38. When draw rod 1~8 is urged
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rearwardly (rightwardly), tines 136 of collet 134 are urged
radially inwardly against retention knob 138 by an annular
projection 141 which extends radially inwardly towards the
center of the bore axtending through the spindle bar. The
radially inward force ex~rted by projection 141 against tines
136 urges the tines against the retention knob to assure that
the toolholder is thus firmly retained in the spindle bar.
Conversely, when draw rod 128 is urged forwardly (leftwardly)
so that tines 136 are no longer urged radially inwardly against
retention knob 138 by projection 141, then, the shank o~ the
single toolholder or multiple spindle toolhead is no longer
irmly engaged in the spindle bar tool receiving socket and
can be removed rom the spindle bar and replaced with a new
toolholder or multiple spindle toolhead.
Although not essential to the operation of the present
ir~vention, draw rod 128 has a bore 142 therethrougn in communi-
cation with a tube 144 within the collet f~r conducting coolant
into collet tube 144 to enable coolant to be conducted through
the collet tube into the tool and through the tool to the
workpiece.
Referring now to Fig. 6 which is an end view of spindle-
head 28 taken along lines 6-6 of Fig. 4, it can be seen that
quill sleeve 132 has a housing 145 integrated thereto and
extending perpendicularly thererom. Housing 145 is t~pically
disposed at an obtuse angle from cylinder 122. A draw rod
driver motor 146 which, as will be seen hereinafter, recipro-
cates draw rod 128 ~Fig. 4) forwardly and rearwardly within
the spindle bar, is fastened by bolts 147 to a plate 148 which
is fastened by bolts 149 to the end of housing 145 distal from
the quill sleeve. The motor is thus mounted to the housing so
that its shaft extends into housing 145 perpendicular to the
axis of quill 130. Quill sleeve 132 has a second housing 150
integrated thereto perpendicular to the axis of the quill and
disposed at an acute angle from quill sleeve housing 145.
Housing 150 has a bore disposed therethrough perpendicular to
the central axis of the quill for receiving a shaft 151 there-
in. Shaft 151 is linked by a yoke 152 to the shaft 153 o a
~6~
-16-
spring-return hydraulic cylinder 15~ which, as will be seen by
subsequent reference to Fig. 7, is mounted to housing 150
parallel to shat 151. A~ frame 155a is fastened to housing
150 so as to extend therebeyond paralleL to shafts 151 and
153. Frame 155a carries a pair of parallel spaced apart
proximity switches 155b and 155c. Proximity switches 155b and
155c are spaced apart on frame 155a such that when cylinder
shaft 153 is fully outwardly extended beyond the cylinder,
proximity switch 155b is actuated by yoke 152 while proximity
switch 155c remains deactuated. Conversely, when cylinder
shaft 153 is retracted into the cylinder following pressuriza~
tion thereof to urge shaft 151 into housing 150, proximlty
sWitch 155c is actuated by yoke 152.
The details of how shaft 151, when urged through the
quill housing into the quill by cylinder 153 operates to
engage the clutch mechanism disposed in the quill for coupling
drive motor 146 to the draw rod to enable draw rod driver
motor 146 to reciprocate draw rod 128 coaxially within the
spindle bar are illustrated in greater detail in Fig. 7 which
is a cross sectional view taken along lines 7-7 of Fig. 6. As
illustrated, draw rod driver motor 146 has a shaft 156 which
extends into a recess within housing 145 for splined engagement
with a drive gear 158 which has a set of drive teeth projecting
from the bottom end thereof. Drive gear 158 has a groove or
channel circumscribed about the periphery thereof for engaging
one end of a horizontally orientad web 160 which is disposed
within the recess in housing 145. Web 160 is attached at i.ts
opposite end to the shaft 162 of a spring-return hydraulic
cylinder 164 which is secured to plate 147 to that its shaft
162 extends into the housing parallel to draw rod driver motor
shaft 156. To assure that web 160 remains substantially
horizontal when cylinder 164 is pressuri2ed and de-pressurized
to reciprocate the drive gear along the motor shaft from and
towards, respectively, the draw rod drive motor, a guide pin
165 is seated in a bore disposed in the housing recess parallel
to the motor shaft and is secured at its upper end to web 160
between driver gear 1-58 and hydraulic cylinder shaft 162.
6~
-17-
A substantialLy "U"-shaped frame 169 having a pair of
horizontally oriented, parallel spaced apart sides, is fastened
to the upper end of cylinder 164 so that shaft 162 o the
cylinder extends perpendicularly through the bottom leg of the
frame. A pair of proximity switches 170a and 170b are each
fastened perpendicularly through a separate one of the legs of
the frame 169 so as to be opposite each other and parallel to
shaft 162. Fastened to the end of cylinder shaft 162 extending
upwardly from cylinder 164 is a horizontally oriented finger
171. During intervals when cylinder 164 is de~pressurized,
the internal cylinder spring urges the cylinder shaft into the
cylinder, thereby displacing finger 171 into proximity with
switch 170b, thus actuating the switch. Conversely, when
cylinder 164 is pressurized, finger 171 is displaced away from
proximity switch 170b towards proximity switch 170a causi~g
the former switch to be deactuated and the latter switch to be
actuated, respectively. By monitoring the conduction states
of proximity switches 170a and 170b, th~ machine tool control
system can determine whether cylinder 164 has been pressurized.
Th drive teeth extendinq from the lower end of driva
gear 158 are complementary to the drive teeth projecting
upw~rdly from the top end of a bevel gear 172 which is rotat-
ably journaled in a bushing 174 secured in a rece3s radially
disposed in the periphery of guill 130 by fasteners 175 so as
to be in communication with the axially extending central bore
through the guill. Before drive gear 158 can be urged into
engagement with bevel gear 172 by cylinder 164 to facilitate
transmission of rotational energy from the draw rod driver
motor to bevel gear 172, quill 130 must be displaced outwardly
(forwardly) from quill sleeve 132 to position bevel gear 172
in axial alignment with drive gear 158. Reciprocation of
quill 130 within quill sleeve 132 is accomplished by cylinder
122 (Fig. 6). To this end, yoke 120, which is fastened to the
shaft of cylinder 122 (Fig. 4), has a plate 176 attached to
the rear end thereof by bolts 178 (only one of which is shown).
The yoke and plate are jointly secured to the forward end of
-18-
quill 130 by bolts 179 (only one of which is shown) which ex-
tends through the yoke and the plate into the quill. When
plate 176 is urged into face to face relationship with quill
130 by bolts 179, a bore in the rearward face of plate 176
communicates with a like-sized bore in the forward face of
quill 130 to form a pocket for receiving a bearing 180 which
is carried on a sleeve 182 that circumscribes the rearward end
of spindle bar 38 extending through yoke 120 and plate 176
into quill 130. A nut 184 in threaded engagement about the
rearward end of spindle bar 38 within quill 130 urges the
flanged rearward end of sleeve 182 against the inner race of
bearing 180. By virtue of the above described en~a~ement of
yoke 120 with quill 130, spindle bar 38 and quill 130 are
displaced forwardly when cylinder 122 (Fig. 4) is pressurized.
Conversely, when cylinder 122 is de-pressurized causing the
cylinder shaft to be retracted into the cylinder, yoke 120
thus urges spindle bar 38 and quill 130 rearwardly.
Once quill 130 is displaced to its forwardmost position
by yoke 120 and cylinder 122 so that bavel gear 172 is in
alignment with drive gear 158, cylinder 164 can then be pres-
surized to urge drive gear 158 into driving engagement with
bev~l gear 172. B~vel gear 172 transmits the rotational
energy imparted thereto by drive gear 158 to a collar 186
rotatably journaled into the bore through the quill so as to
be perpendicular to, and in driving engagement with, gear 172.
Collar 186 i~ rotatably journaled about a shaft 190 which is
iournaled for rotation within the centrally disposed, axially
extending bore through the quill. Collar 186 is constrained
from moving axially on shaft 190 by a pin 192 which is seated
in an annular groove disposed radially in khe quill so as to
be perpendicular to the central axis of shaft 190. A horizon-
tally disposed key 193 is fastened to the top of bushing 174
by bolt 194 and extends from the bushing into a groove inscribed
circumferentially about the periphery of pin 192 to constrain
the pin against vertical movement.
L6~
--19--
Collar 186 is fabricated with a set of drive teeth that
project from the forward end thereof for mating engagement
with the drive teeth on the rearward end of a drive gear 196
carried on the forward end of shaft 190 in splined engagement
therewith so as to rotate co-jointly with the shaft. Gear 196
has a groove circumferentially inscribed in the outer periphery
thereof for engaging a vertically oriented pin 198 which is
secured by a bolt 200 to the forward (leftward) end of a rod
202 that is disposed in an axially extending bore in the quill
for axial movement within this bore along a path parallel to
the axis of rotation of shaft 190. A spring 204, disposed
between the rearward (rightward) end of rod 202 and the rear-
ward ~uill wall urges rod 202 forwardly to bias gear 196 away
from collar 186 and against a spacer 205 carried on the rear-
ward end of a sleeve 206 circumscribing the forward end of
shaft l90. While drive gear 196 is forwardly biased by the
combination of pin 198, rod 202 and spring 204, drive gear 196
remains disengaged from collar 186. Once quill 130 is urged
forwardly by cylinder 1~2 ~Fig. 6) to align the teeth on bevel
gear 172 with the drive teeth on gear 158, shaft 151 becomes-
aligned with an opening 207 disposed radially into the guill.
Pr~ssurizing cylinder 154 serves to urge shaft 151 through
openiny 207 and into a chamfered bore 208 in bar 202 which is
slightly offset from opening 207. As shaft 151 enters cham-
fered bore 208, the shaft urges the bar 202 rearwardly against
spring 204 causing the combination of pin 198 and bar 202 to
bias drive gear 196 rearwardly into engagemant with collar
186. During intervals while drive gear 196 is biased into
engagement with collar 186, rotationaL energy can be transmit-
ted from the draw rod driver motor to the shaft 190 so that
the shaft may be threaded into or off of draw rod 128 in a
manner described in greater detail hereinafter to urge the
draw rod rearwardly and forwardly, respectively, to engage and
disengage, respectively, a toolholder loaded in the tool
receiving socket in the forward end of spindle bar 38.
The details of how shaft 190 threadedly engages draw rod
128 to reciprocate the draw rod within the spindle bar may be
~6~
-~o--
best seen by reference to Fig. 8 which is an enlarged sectional
view of the forward end of shaft l90 of Fig. 7. As illustrated,
a threaded stud 212 has its flanged head 214 integrated to the
head 215 of shaft 190 for co~joint rotation with the shaft.
The threads of stud 212 matingly engage complementary threads
on the interior surface of a bore in the rearward end of draw
rod 128. When shaft lgO is rotatably driven in a clockwise
direction, threaded stud 212 is threaded into draw rod 128 to
urge the draw rod rearwardly. A spacer washer 216, having an
interior bore large enough to receive stud 212, but smaller
than the outer diameter of draw rod 128, is carried on the
stud between the leftward side of the flanged head 214 of the
stud and a sleeve 218 circumscribing the rearward end of the
draw rod for absorbing the forward thrust of the flanged end
214 of stud 212 as the stud is threaded into the draw rod.
Sleeve 206, which circumscribes head 215 of shaft 190, absorbs
the rearward thrust exerted by flanged end 214 thereagainst as
stud 212 is threaded out from draw rod 128.
Referring back to Fig. 7, it will be recalled that draw
rod 128 may advantageously be made hollow to conduct coolant
into a single toolholder or multiple spindle toolhead. Where
tha draw rod is made hollow, shaft 190 is likewise made hollow
and is fabricated with a coolant tube 2.20 extending rearwardly
therebeyond for coupling to a rotary fluid coupling 222 which
supplies coolant into the coolant tube 220 from a source of
coolant (not shown). Rotary coupling 222 advantageously
conducts coolant from the coolant source into coolant tube 220
as shaft l90 and coolant tube 220 rotate co-jointly.
As further illustrated in Fig. 7, a lubrication inlet 223
is disposed into housing 145 for conducting lubricating fluid
from a source of lubricating fluid (not shown) into the hous-
ing. The lubricating fluid conducted into housing 145 through
lubrication inlet 223 lubricates bevel gear 172 and also
lubricatas collar 186 and gear 196 when they are brought into
allignment with drive gear 158 following the forward (leftward)
movement of quill 130.
6~
-21-
As indicated previously, spindle bar 38 can be extended
outwardly from the spindlehead at times other than during a
tool change cycle to facilitate a deep boring or drilliny
operation when the appropriate toolholder is secured in the
tool receiving socket of the spindle bar. Referring now to
Fig. 6, quill 130, and hence spindle bar 38, are locked against
transverse movement, once the spindle bar is forwardly extended
from the spindlehead by a quill shot pin cylinder 224 which is
secured to a housing 225 integrated to, and extending perpen-
dicularly from, quill sleeve 132 so that the quill shot pin
cylinder shaft (not shown) extends into housing 225 perpendicu-
larly to the longitudinal quill axis. The details of how
quill shot pin cylinder 224 operates to lock quill 130 and
hence, spindle bar 38 against transverse movement may best be
understood by reference to Eig. 9 which is a cross sectional
view taken along lines 9-9 o Fig. 6. As illustrated, the
shaft of cylinder 224 (shown in phantom) extends into a bore
in housing 225 in communication with quill 130. Disposed
within this bore in housing 225 is a quill shot pin 228 which
is secured at one end thereof to the shaft of cylinder 224 so
as to be reciprocated within the bore responsive to pressuriza-
tion of cylinder 224. The end of quill shot pin 228 distal
from cylinder 224 is cham~ered for mating engagement in a
complementary chamfered quill shot pin seat 229 pressed into a
bore in the outer periphery of the quill. The relative loca-
tion of quill seat 229 in the periphery o quill 130 is such
that when the spindle bar and the quill are at their forward-
most position, quill seat 229 is in alignment with quill shot
pin 228 so as to enable the quill shot pin seat to receive the
chamfered end of the quill shot pin following pressurization
of cylinder 224. Thus, pressurization of cylinder 224 serves
to lock quill 130 and hence spindle bar 38 ~Fig. 6) against
transverse movement. Referring back to Fig. 6 for a moment, a
pair of limit switches 230a and 230b are fastened on opposite
sides of housing 225. Each limit switch, such as limit switch
230a illustrated in phantom in Fig. 9, has an actuator extending
through the housing so as to contact the quill shot pin as it
6~
-22~
is reciprocated. Limit switches 230a and 230b are spaced
apart such that limit switch 230a is actuated by the quill
shot pin when the quill shot pin is furthest from the quill as
illustrated in Fig. 9, which occurs when cylinder 224 is
de-pressurized. Conversely, limit switch 230b is actuated by
the guill shot pin when the sho~ pin is urged into engagement
with the quill shot pin seat. Thus, by monitoring the relative
conduction states of limit switches 230a and 230b, the machine
tool control system can readily ascertain the relative position
of quill shot pin 228 within housing 225.
In addition to locking quill 130 and hence spindle bar
38 against axial movement, particularly during a tool change
cycle, it is also desirable to lock the spindle bar against
rotational movement, expecially during a tool change cycle so
that the toolholder keyway (not shown) inscribed in tool
receiving socket 129 (Fig. 4) in the forward end of the spindle
bar is in alignment with the key on the shank of the toolholder
or multiple spindle toolhead, thereby assuring firm engagement
of the single toolholder or multiple spindle toolhead input
shank in the spindle bar tcol receiving socket. Referring now
to Fig. 10, which is a cross sectional view taken along lines
lO-lO of Fig. 6, locking of the spin~le bar against angular
rotation is accomplished by a plunger 236 which is journaled
through interior spindlehead walls 75a and 75b so as to ba
parallel to spindle bar 38. The rearward (rightward) end of
plunger 236 is coaxial with, and is secured to, the shaft of a
spring returned hydraulic cylinder 238 which is attached to
the rearward end of spindlehead 28 so as to be parallel with
quill 130. When hydraulic cylinder 238 is pressurized in
response to a command from machine tool command system, the
cylinder shaft and hence plunger 236 are urged forwardly
(leftwardly) so that the forward end of the plunger extends
into one of the passageways disposed through keylock disk 116
a~ equidistantly spaced intervals adjacent to the periphery of
the keylock disk. While cylinder 238 remains pressurized,
plunger 236 remains in engagement with the keylock disk so as
to prevent spindle bar rotation.
~2~6~
-23
At the rearward end of hydraulic cylinder 238, there i5
affixed a palr of limi~ switches 240a and 240b which are each
coupled to the ma~hine tool control system. Limit switch 240a
is actuated by the rearward end (not shown) of the hydraulic
cylinder shaft when cylinder 238 is de-pressurized and con-
versely, switch 240b is actuated by the hydraulic cylinder
shaft when cylinder 238 is pressurized. Thus, by monitoring
the conduction state of limit switches 240a and 240b, the
machine tool control system can ascertain whether or not
c~linder 238 has in fact heen pressurized to facilitate locking
of the spindle bar against rotational measures.
To assure that the spindle bar is at a predetermined
angular orientation prior to pressuri~ation of hydraulic
cylinder 238, keylock disk 116 has a dog 242 extending radially
from the periphery of the keylock disk. A plurality of proxim-
ity switches 244 (only one of which is shown) are secured
within the interior of spindlehead 28 in spaced apart relation~
ship about the orbit of dog 242 so that each proximity switch
is actuated by dog 242 when keylock disk 116 is oriented at a
particular angular orientation. By sensing the present conduc-
tion state of each of proximity switches 244 and by recalling
the conduction states each of proximity switches 244 during
the just-prior interval, the machine tool control system can
ascertain not only the relative angular orientation of the
spindle bar, but also can discern the direction of the spindle
bar rotation. In this way, machine tool control system can
determine whether or not spindle bar is at a particular angular
orientation prior to pressurizing cylinder 238 to lock the
spindle bar against rotation.
The counter balancing apparatus which counterbalances
tool transfer arm carrier 50 as it moves on tower 46 along the
Y axis is illustrated in Fig. ll. The heart of the counter-
balancing apparatus is a hydraulic cylinder 248 which is
secured to the side of tower 46 by bolts 249 so that the shaft
250 of the cylinder extends upwardly from the cylinder parallel
to the Y axis. Cylinder 248 is typically fabricated so that
shaft 25C is spring biased downwardly into the cylinder, the
6~
-24-
force required to bias shaft 250 upwardly being approximately
equal to the downward gravitational force on tool transfer arm
carrier 50. The upward end of cylinder shaft 250 is linked to
the tool transfer arm carrier by a chain 251 which passes
across the top of the tower over each of a pair of sheaves
252a and 252b which are each rotatably journaled in a separate
one of sheave housings 254a and 254b, respectively, each
secured to a separate one of plates 258a and 258b, respectively,
fastened to the top of tower 46. Although it would be feasible
to link the end of chain 251 directly to the upward most end
of cylinder 250, in the presently preferred embodiment, a
sheave 260 is affixed to the upward most end of cylinder shaft
250 so that the chain passes through sheave 260 and is attachad
to the underside of plate 258b. Employing a sheave 260 at the
upward most end o cylinder shaft 250 for passing the chain
ther~through serves to increase the mechanical advantage of
cylinder 248 and thus allows use of a smaller, less expensive
cylinder than would be the case if the mechanical advantage of
the cylinder were reduced by virtue affixing the end of chain
251 directly to the upper most end of the cylinder shaft.
The detail6 of how sheave 252b is secured in sheave
housing 254b are illustrated in Fig. 12 which is a cross
sectional view ta}cen along lines 12-12 of Fig. 11. Since the
details of sheave 252a and sheave housing 254a are identical
to the details of sheave 252b and sheave housing 254b, only
sheave 252b and sheave housing 254b are described in detail
hereinafter. As may be observed from Figs. lZ, sheaves housing
254b comprises a horizontal bottom plate 262 which is secured
by bolts 264 to plate 258b which is secured to the top of
tower 46. A pair of vertically extending walls 266a and 266b
are each fastened to plate 262 in spaced apart parallelism
typically by being welded thereto. Sheave 252b is interposed
between walls 266a and 266b and is supported from the walls by
a pin 268 which is horizontally journaled through the wall.s.
A roller bearing 270, circumscribing the medial portion of pin
268, rotatably journals sheave 252b about pin 268 so as to
permit the sheave to rotate freely.
~6~
-25-
It should be noted that ability of tool change arm carrier
80 to be positioned at any location along tower 46 not only
enables the tool change arm to engage tools rom any of the
three tool storage disks 62 but also enables the tool change
arm to be moved to any Y axis coordinate location of the
spindle to enable tool exchange with the spindle without first
having to locate the spindle to a Y axis home position.
Referring now to Figs. 13-16, there are shown the details
of how housing 55 carries pivot 56. As is illustrated in Fig.
13 which is the front view of the housing, a plurality of
threaded passages 272, typically four in number, are disposed
longitudinally into pivot 56 parallel to the central axis of
the pivot, each passage receiving the threaded end of bolt
(not shown) extending through the tool change arm into the
pivot. To facilitate rotation of the tool change arm about
each of a pair of mutually orthogonal axes, housing 55 is
secured by bolts 278 (only one of which is shown) to the
outwardly exposed face of pivot 53 so that the housing rotates
with pivot S3 about an axis perpendicular to the axis of
rotation to the pivot 56 journaled within the housin~. Driviny
engayement between housing 55 and pivot 53 is assured by a key
280 (Fig. 13) which is fastened to khe housing by a bolt 282
so that the key engages a complementary keyway (not shown)
inscribed in the outer periphery of the pivot.
The interior details of housing 55 are illustrated in
Fig. 16 which is a cross sectional view taken along lines
16-16 of Fig. 13. As illustrated, pivot 56 is rotatably
journaled in housing 55 by a pair of bearings 284a and 284b
carried on the forward and rearward ends, respectively, of the
pivot. The pivot is restrained from axial movement within the
housing by a nut 285 which threadedly engages the rearward end
of the pivot so as to bear against the inner race of ball
bearing 284b whose outer race abuts a shoulder which extends
radially inwardly into the bore in the housing which receives
the pivot. When nut 285 is threaded onto the rearward end of
the pivot so as to bear against the inner race of bal] bearing
284b, the rearward edge of the flange 286 inteyrated to the
-26-
forward end of the pivot bears against a spacer 287 to urg~
the spacer against the inner race of ball bearing 284a whose
outer race abuts a shoulder within the housing extending
radially inwardly into the bore through the housing thus
preventing axial pivot movement. Lubricating fluid is supplied
to each of bearings 284a and 284b from a source of lubricatinq
fluid (not shown) through a separate one of lubrication pas-
sages 288a and 288b, respectively, disposed through housing
276 in communication with each separate bearing.
Pivot 56 is rotatably driven by a rotary hydraulic actu-
ator ~90 which is fastened to the rearward (leftward) end of
housing 55 by bolts 292 (only one of which is shown) so that
the shaft 294 of the rotary hydraulic actuator extends through
an opening in the rearward end of housing for splined engage-
ment with the rearward end of the pivot. When pivot 56 is
rotatably driven by rotary hydraulic actuator 290 following
pressurization of the hydraulic actuator responsive to a
machine tool control system command, the pivot imparts a
rotational torque to a hollow bore cam plate 296 ~hich circum- -
scribes the flanged end 286 of pivot 56. Cam plate 296 is
keyed by a key 298 to the flanged end 286 of pivot 56 and the
cam plate is bolted and dowled to tool change arm 57 50 as
pivot 56 is rotatably driven by rotary hydraulic actuator 290,
the cam plate and the tool change arm rotate co jointly with
the pivot. As will be described in greater detail with respect
to Fig. 19, cam plate ~96 limits the orbit of tool change arm
57 rotation as the tool change arm is rotatably driven by the
pivot following cam plate contact with a stop member described
hereinafter) when the stop member is extended forwardly from
housing 55.
Referring now to Figs. 15 and 16 jointly, two movable
stop members 300a and 30Cb are each slidably fastened on the
side and bottom, respectively, of housing 55 so as to be
retractable towards and extendable away from the housing along
a path parallel to the axis of pivot 56 rotation. A fixed
stop member 300c is mounted to housing 55 parallel to and
directly beneath movable stop member 300b~ Each of movable
6~
-27-
stop members 300a and 300b is displaced along its axis towards,
and away from cam plate 296 by a separate one of a pair o
spring return hydraulic cylinders 303a and 303b, respectively,
which are each secured to the side and bottom of housing 55,
respectively, by bolts 304 so that the shaft of each hydraulic
cylinder is coaxial with, for coupling to, a separate one of
stop members 300a and 300b, respectively.
To ascertain the relative position of movable stop member
300a during machine tool operation, a pair of proximity
switches 306a and 306b are mounted in a frame 307 which is
secured to housing 55 so as to extend rearwardly therebeyond
parallel to that portion of the shaft o cylinder 303a extend-
ing rearwardly from the cylinder. Proximity switches 306a and
306b are perpendicularly mounted in frame 307 in parallel
spaced apart relationship so that switch 306a, which is fur-
thest from the housing, is actuated by an annular flange on
the rearwardly extending portion of the shaft of cylinder 303a
while the cylinder is de-pressurised. Pressurization of
cylinder 303a to urge stop member 300a forwardly (rightwardly)
into engagement with the cam plate, causes the rearwardly
extending portion of the cylinder shaft to be retracted into
cylinder 303a so that switch 306b is actuated by the cylinder
shaft annular flange while switch 306a becomes deactuated.
Thus, by monitoring the conduction state of each of proximity
switches 306a and 306b, the machine tool control system can
readily ascertain whether or not cylinder 303a has been pres-
surized to urge movable stop member 300a forwardly into contact
with cam 296 to limit the orbit of tool change arm 57.
Because of the close spacing between the rearward end of
hydraulic cylinder 303b and rotary hydraulic actuator 290, a
slightly different proximity switch arrangement is provided
for detecting the pressurization of cylinder 303b than the
proximity switch arrangement described above for detecting the
movement of movable stop member 300a. Referring now to Fig.
15, it can be observed that movable stop member 300b has a
pair of parallel, spaced apart pins 310a and 310b extending
downwardly from the stop member through a longi-tudinal channel
L6~
-28-
in fixed stop member 300c. A pair of parallel, spaced apart
proximity switches 312a and 31~b are each horizontally secured
in a frame 313 affixed to stop member 300c so that each switch
is perpendicular to each of pins 310a and 310b. The spacing
between proximity switches 312a and 312b is such that when
hydraulic cylinder 303b is depressurized to urge stop member
300b rearwardly away from cam plate 296, switch 312b is in
proximity with and is actuated by pin 310b. Conversely, when
cylinder 303b is pressurized to urge stop member 300b forwardly
to engage cam plate 296 in a predetermined orientation, so as
to limit the orbit of tool change arm 57, switch 312a is in
proximity with, and is actuated by pin 310a. Thus, by monitor-
ing the conduction states of each of proximity switches 312a
and 312b, the machine tool control system can readily ascertain
the relative position of stop member 300b.
Referring back to Figs. 13 and 14, proximity switches
314a and 314b are each horizontally secured in a separate one
of frames 315a and 315b, respPctively, which are mounted to
the top and to the side of housing 55 so that proximity
switches 314a and 314b are in direct vertical alignment with
each other. Each of proximity switches 31~a and 314b is
secured by its corresponding frame in face to face relation-
ship with cam plate 296 (Fig. 15) so as to be activated by one
of the lobes of cam plate 296 (described in detail with respect
to Eig. 19) when cam plate lobe is directly opposite to the
proximity switch. As will become clear hereinafter, by moni-
toring the present conduction states of proximity switches
314a and 314b and by memorizing the previous conduction states
of proximity switches 314a and 314b, the machine tool control
system can ascertain relative an~ular orientation of the tool
change arm.
To sense the angular orientation of housing 55 as the
housing is rotated by pivot 53 about the central axls of the
pivot, a pair of proximity switches 316a and 316b are each
hori~ontally secured in a frame 317 mounted to the top of the
housing as illustrated in Fig. 15. Switches 316a and 316b are
secured in frame 317 in parallel, spaced apart relationship so
-29-
that each switch, such as switch 316a illustrat~d in Fig. 13,
is opposite to and in face to face relationship with the side
of tool change arm carrier 50. Affixed to the side of the
tool change arm carrier within the orbit of the proximity
switches is a pair of trip dogs 320 (only one of which is
shown in Figs. 13 and 14), the trip dogs being separated by a
90 arc so that after housing 55 is rotated from its vertical
position, as illustrated in Figs. 13 and 14 to its horizontal
position, as illustrated in Fig. 2, one of the proximity
switches, is actuated by one of trip dogs 320. Conversely,
after the housing is rotated from its horizontal to its verti-
cal position, the other of the proximity switches is actuated
by the other of the trip dogs. By monitoring the conduction
state of proximity switches 316a and 316b, the machine tool
control system can ascertain the relative angular orientation
of the housing.
The details of tool transfer arm 57 are illustrated in
Figs. 17 and 18, Fig. 17 being a frontal view of the tool
change arm and Fig. 18 being a cross sectional view of the
tool change arm taken along lines 18 18 of Fig. 17. In the
presently preferred embodiment, the tool change arm includes a
hub 330 which is secured by bolts 278 (Fig. 17) to pivot 56 50
that the rearward (leftward end of the hub is in face-to-face
relationship with cam plate 296 which circumscribes the pivot
as illustrated in Fig. 18. Integrated to each of the ends of
hub 330 is a separate one of hub projections 332a and 332b,
respectively. As illustrated in Eig. 18, each of a pair of
plates 336a and 336b is fastened to a separate one of forward
and rearward edges, respectively, of hub projection 332a so
that the plates extend from the hub projection in spaced apart
parallelism. In a likewise fashion, each of a pair of plates
336c and 336d is fastened to the front and rearward edges,
respectively, of hub projection 332b so that the plates extend
from the hub projection in spaced apart parallelism.
Interposed between plates 33Sa and 336b, so as to
extend therebeyond, are a pair of opposing jaws 338a and 338b,
~LZ~
-30-
each jaw pivoting about a separate one of pins 340a and 340b,
which are perpendicularly disposed through the plates. Inter-
posed between plates 336c and 336d are a pair of opposing jaws
338c and 338d, each jaw being pivotal about a separate one of
pins 340c and 340d which are perpendicularly disposed through
plates 336c and 336d. Each pair of opposing jaws such as jaws
338c and 338d, when pivoted towards each other, serve to
engage a shank of a toolholder 58 or multiple spindle toolhead
59 interposed between the jaws. Conversely, when each of the
pair of opposing jaws, such as jaws 338a and 338b, for example,
are pivoted apart from each other, the shank of the toolholder
or multiple spindlehead, previously gripped by the ja~s is
thus released therefrom.
Each of the opposing jaws 338a and 338b is pivoted towards
and away from each other by a separate one of webs 342a and
342b, respectively, which are each pinned at one end thereof
to the end of a separate one of jaws 338a and 338b, respective-
ly. Webs 342a and 342b are jointly pinned at their opposite
end to the shaft 343a of a hydraulic cylinder 344a which is
disposed within hub 330 so that cylinder shaft 343a extends
outwardly from the hub in spaced apart parallelism between
plates 336a and 336b as illustrated in Fig. 18. Hydraulic
cylinder 344a has a pair of inlet ports 346a and 346b associ-
ated therewith for conducting hydraulic fluid into the cylinder
on opposite sides of a piston 347a which is carried on the end
of cylinder shaft 343a disposed within the cylinder. Inlet
ports 346a' and 346b are each connected by a separate pair of
passa~es 348a and 348a' and 348b and 348b', respectively, to a
separate one of a pair o fluid channels 350a and 350b which,
as illustrated in Fig. 16 are disposed axially in pivot 56 for
conducting hydraulic fluid to cylinder 344a.
Jaws 338c and 338d are each pinned at their inward most
end to the end of a separate one o webs 342c and 342d, respec-
tively. Webs 342c and 342d are jointly pinned at their oppo-
site ends to the shaft 343b of a hydraulic cylinder 344b which
is disposed within hub 330 so that the shaft 343b of the
cylinder is interposed between plates 336c and 336d in spaced
-31-
apart parallelism with both plates. Hydraulic cylinder 343b
has a pair of inlet ports 346h and 346b' associated therewith
for conducting hydraulic fluid into the cylinder at opposite
sides of a piston 347b at the end of cylinder shaft 343b
disposed within the cylinder. Each of inlet ports 346b and
346b' is linked by a pair of interconnecting passageways 348c
and 348c' and 348d and 348d', respectively, to a separate one
of fluid channels 350c and 350d disposed longitudinally through
pivot 56 (Fig. 16). Although not shown, means are provided
within each of cylinders 344a and 344b to bias the cylinder
shaft outwardly from the cylinder so that in the event of a
hydraulic failure, no accidental tool release occurs.
Referring back to Fig. 16, it can be observed that each
of axially extending passageways 350a-350d in pivot 56 communi-
cates with a separate one of fluid inlets 352a-352d, respec-
tively, disposed through housing 55. Although not shown, each
fluid inlet is connected to a source of hydraulic fluid through
a valve actuated by the machine tool control system. In this
manner, cylinders 344a and 344b (Fig. 17) can be actuated
independently of one another so as to enable a tool gripped ~y
one of the pair of opposing jaws to be released without release
of the tool gripped by the other pair of opposin~ jaws. To
avoid the leakage of hydraulic fluid carried by one of fluid
inlets into an adjacent inlet, each of fluid inlets 352a-352d
is separated by an oil trap 354 on either side thereof for
trapping any of the hydraulic fluid leaking from ths inlet.
By trapping the oil leaking from an adjacent inlet, oil traps
354 tend to prevent inadvertent pressurization of hydraulic
cylinders 344a and 344b (Fig. 17).
As illustrated in Fig. 15, tool change arm 57 has a pair
of fingers 356a and 356b, each on opposite ends of hub 330.
As is better shown in Fig. 18, each of fingers 356a and 356b
is affixed to a separate one of shafts 343a and 343b, respec-
tively, of cylinders 344a and 344b, respectively, so that each
finger extends substantially horizontally from the cylinder
shaft through a channel in a separate one of plates 336b and
336d, respectively. When a separate one of the hydraulic
~2~
-32-
cylinders of the tool chang~ arm, such as cylinder 344a, for
example, is pressurized to urge an associated pair of opposing
jaws, such as jaws 338a and 338b, apart to release the tool-
holder or multiple spindlehead shank previously gripped between
the jaws, then 356a is urged radially inwardly (downwardly in
Fig. 18) to a second position from its first or radially outer
most (upward most) position. Conversely, if a tool change arm
hydraulic cylinder, such as cylinder 344b, were pressurized to
urge its associated jaws such as jaws 338c and 338d towards
one another to engage the shank of a toolholder or multiple
spindle toolhead therebetween, then, finger 356b would move to
its first or radially outward most position from its second or
radially inward most position. Thus, the radial location of
each of fingers 356a and 356b from hub 330 is indicative of
whether or not the jaws of a corresponding one of opposing jaw
pairs 338a and 338b and jaw pairs 338c and 338d, respectively,
are engaging the shank of a toolholder or multiple spindle
toolhead therebetween.
As is best illustrated in Eigs. 13 and 14, housing 55 has
a pair of right angla frames 358a and 358b attached to the top
and the outwardly exposed side of the housing, respectively.
Frames 358a and 358b each secure a pair of horizontally mounted
proximity switches 360a and 360b and 360c and 360d, respective-
ly. Proximity switches 360a and 360c are each mounted in a
separate one of frames 358a and 358b, respectively, so that
each proximity switch liew within the orbit made by fingers
356a and 356b as the tool change arm is rotated while ~ach
finger is at its first or radially outward most position.
Proximity switches 360b and 360d are each secured in a separate
one of frames 358a and 358b, respectively, so that each proxim-
ity switch lies within the orbit made by fingers 356a and 356b
as the tool change arm rotates while each finger is at its
second or radially inward most position. When tool change arm
57 is vertically oriented as illustrated in Fig. 18, so that
finger 356a lies vertically above finger 356b, then, switch
360a is actuated and switch 360b is deactuated while jaws 338a
and 338b (Eig. 18) are biased together to engage the shank of
Z~33-
a single toolholder or multiple spindle toolhea~ therebetween.
Conversely, at the same orientation of the tool change arm,
the conduction states of switches 360a and 360b reverses once
jaws 338a and 338b are biased apart to release the shank of
the toolholder or multiple spindle toolhead previously engaged
therebetween In a similar manner, when tool change arm 57 is
horizontally oriented as illustrated in Fig. 1, so that finger
356b (Fig. l8) overlies frame 358b (Fig. 19), then switch 360d
is actuated and switch 360c is deactuated while jaws 338c and
338d (Fig. 17) remained biased towards one another to engage
the shank of a multiple spindle toolhead or single toolholder
therebetween. If, while the tool change arm is horizontally
oriented as just descri~ed, jaws 338c and 338d are biased
apart to release the shank of a single toolholder or multiple
spindle toolhead previously engaged by the jaws, then the
conduction state of switches 360c and 360d reverses. As will
become better understood hereinafter, switches 360a through
360d serve a very important purpose in that switches 360a and
~60b indicate the relative clamping state of that pair of tool
transfer arm jaws transferring tools to and from the tool
change magazine while switches 360c and 360d indicate the
relative clamping position of the tool transfer arm jaws which
transfer tools to and from the spindle bar.
Before proceeding to describe the sequence of operations
occurring during a tool change cycle, reference should be had
to Fig. 19 which is a frontal view of housing 55 with the tool
change arm removed to illustrate the configuration of cam
plate 296. As illustrated, cam plate 296 is configured with
three separate cam lobes 365a, 365b and 365c, respectively.
When the tool change arm is vertically oriented as is illus~
trated in Fig. 18t the cam plate is oriented as shown in Fig.
l9 so that cam lobes 365a and 365b are located at approximately
8 o'clock and 7 o'clock, respectively. While cam plate 296 is
oriented as illustrated in Fig. l9, cam plate lobe 365c extends
approximately between 12 o'clock and 2 o'clock. Cam plate
lobe 365c is dimensioned so that during rotatlon of the tool
change arm, the cam plate lobe will abut either of stop members
~LZ~
-34-
300a and 300b when the stop members are extended, but the cam
plate lobe is of too short a radius to abut fixed stop member
300c. Unlike cam plate lobe 365c, cam plate lobes 365a and
365b are dimensioned to abut fixed stop member 300c as well as
movable stop 300a and 300b during tool change arm rotation.
During a tool change cycle, which will be described in greater
detail immediately hereinafter, stop members 300a and 300b are
extended and retracted at predetermined intervals to limit the
orbit of the tool change arm so that a tool transfer between
the tool storaga magazine and the spindle bar can be completed
rapidly and efficiently.
The sequence of steps occurring during a tool change
cycle will now be described with reference to Figs. 20a through
20g, which illustrate, in sequence view, the angular tool
change arm orientation during various steps of the tool change
cycle. In proceeding to describe a typic~l tool change cycle,
it will be assumed that a designated machining operation has
just been completed and that spindle bar 38 (Figs. 1-3), which
now contains the spent tool, has been retracted into spindle
34 (Eigs. 1-3) and spindlehead 28 and upright 22 (Figs. 1-3)
both have been moved to their respective tool change positions.
Referring now to Fig. 20a, at the outset of a tool change
cycle, tool change arm 57 is vertically oriented so that tool
change arm jaws 338a and 338b which are presently empty, that
is to say, that no tool is engaged therebetween, lie vertically
above tool change arm jaws 338c and 338d which are likewise
empty at this time. While the tool change arm is vertically
oriented as illustrated in the figure, proximity switch 314b
(Fig. 19) is actuated to signify to the machine tool control
system that, in fact, the tool change arm is in the vertical
orientation previously described. Also, at this time, stop
members 300a and 300b, both illustrated in Fig. 19, are retrac-
ted and extended, respectively, so as to permit tool change
arm 57 to make a 90 arc in the clockwise direction when pivot
56 (Figs. 13-16) is rotated clockwise by rotary hydraulic
actuator 290 ~Fig. 16). Counterclockwise rotation of tool
-35-
change arm 57, however, is prevented due to the abutment of
cam lobe 365b against fixed stop member 300c ~Fig. 19~.
Once the tool change arm is vertically oriented, as
indicated by the actuation of proximity switch 314b (Figs. 13,
14 and 19), then rotary hydraulic actuator 54 is pressurized
to pivot housing 55 thareby rotating the tool change arm about
the axis of pivot 53 (Figs. 13-14~ so that the tool change arm
becomes parallel to spindle bar 38 (Fig. 1) as illustrated in
Fig. 2. After the tool change arm has been tilted so as to be
parallel with spindle bar 38, proximity switch 316a (Fig. 13)
is actuated by a dog (not shown) fastened to the side of tool
change arm carrier 50. Following actuation of proximity
switch 316a, the machine tool control system causes tower 46
(Fig. 2~ to move along ways 44 (Fig. 2) towards tool storage
magazine 60 (Fig. 2) so that tool change arm jaws 338a and
338b (Figs. 17 and 18) can then engage a toolholder or multi-
ple spindle toolhead that had been indexed to the ready posi~
tion of the tool storage magazine. Until the tool change
tower is positioned along ways 44 (Fig. 2) so that jaws 338a
and 338b actually surround the shank of the toolholder or
multiple spindle toolheads then at the ready position of the
tool storage mayazine, the jaws are biased apart from one
another so that switch 360b (Figs. 13 and 14) is actuated
while switch 360a (Eigs. 13 and 14) is not. Once the tower
has reached its intended destination along ways 44 so that
jaws 338a and 338b fully circumscrlbe the shank of the tool-
holder or multiple spindle toolhead then at the tool storage
magazine ready position, then, the jaws are then biased towards
one another to engage the shank of the multiple spindle tool-
head or toolholder then at the ready position, causing the
conduction state of switches 360a and 360b to reverse.
Upon reversal of the conduction state of switches 360a
and 360b, the machine tool control system causes tool chang~
arm carrier 50 (Fig. 11) to be displaced upwaxdly on tower 46
so that the toolholder or multiple spindlehead then engaged by
one of the grippers of tool change arm 57 will clear the
-36-
pocket of tool storage disk 62. After the tool storage maga-
zine is displaced upwardly, then tower 46 is displaced forward-
ly on platform 43 away from the tool storage magazine. When
the tool change tower is at its furthest most posltion from
the tool storage magazine, then, pivot 53 (Fig. 19) is rotated
to return housing 55 and hence, tool change arm 57 to their
vertical position previously illustrated in Fig. 11. Once the
tool change arm returns to its vertical position, then proxim-
ity switch 316a ~Fig. 13) becomes actuated by dog 320 (Fig.
13) while proximity switch 316b becomes deactuated. The
actuation of switch 316a causes the machine tool control
system to pressurize rotary hydraulic actuator 290 (Figs. 15
and 16) to rotate tool change arm 57 clockwise about an arm
90 as illustrated in Fig. 20b. The clockwise rotation of
tool change arm 57 limited to a 90 arc by virtue of the
abutment of cam plate lobe 365c (Fig. 19) with stop member
300b (Eig. 19) which, as will be recalled, was previously
extended at the outset of the tool change cycle.
After the tool change arm is horizontally oriented,
as shown in Fig. 20b, such that still empty jaws 338c and 338d
are located to the left of jaws 338a and 338b which now engage
a fre-sh toolholder or multiple spindle toolhead therebetween,
proximity switch 314a which was previously deactuated now
becomes actuated and switch 314b which was previously actuated
now becomes deactuated. Following the actuation of proximity
switch 314a, the machine tool control system causes platform
43 (Figs. 2 and 11) to be displaced along ways 40 towards
spindlehead 28 (Fig. 2). As platform 43 moves towards spindle-
head ~8, spindle bar 38 (Fig. 1) is extended out from the
spindle so as empty jaw 338c and 338d to engage the spent
toolholder or multiple spindle toolhead then engaged in the
spindle bar tool receiving socket. Until jaws 338a and 338b
actually engage the spent toolholder or multiple spindle
toolhead, proximity switch 360c (Fig. 19) remains actuated
while switch 360d remains unactuated.
As the toolholder jaws are biased towards one another to
engage the spent toolholder therebetween, the conduction state
6~
-37-
of proximity switches 360ç and 360d reverse. Upon the reversal
of the conduction state of proximity switches 360c and 360d,
the machine tool control system causes the spindle bar to
retract into the spindlehead and further causes stop member
300b, which had been extended, to be retracted into housing
55. Once stop member 300b is retracted, as indicated by th~
change in conduction states of proximity switches 312a and
312b (Eig. 16), tool change arm 57 is further rotated in a
clockwise direction about an arc 180 until cam lobe 365a
(Fig. 19) abuts fixed stop member 300c (Fig. 19). When rotated
180 in a clockwise direction from its previous position,
illustrated in Fig. 20b, tool change arm 57 i5 now oriented as
illustrated in Fig. 20c, such that jaws 338a and 338b which
now engage the fresh tool, are located to the left of jaws
338c and 338d which engage the previously spent tool. Once
tool change arm 57 is oriented, as illustrated in Fig. 20c,
respectively, proximity switch 314a, which had been previously
actuated, is thus deactuated. Upon deactuation of proximity
switch 314a, the machine tool control system causes the spindle
bar to be advanced from the spindlehead to engage the new
toolholder presently gripped by jaws 338a and 338b. After the
spindle bar is fully extended from the spindlehead to receive
the toolholder, and draw rod 128 (Fig. 5) is urged rearwardly
to clamp the toolholder in the spindle bar, then jaws 338a and
338b are biased apart to release the toolholder previously
gripped thereby. As jaws 338a and 338b are urged apart,
proximity switch 360c becomes actuated and proximity switch
360d becomes deactuated.
When the conduction state of proximity switches 360c
and 360d reverses, the machine tool control system causes
platform 43 to move along ways 40 away from the spindleh~ad
while at the same time stop member 300b, now retracted, is
~xtended forwardly. Once the platform reaches its most distal
point from spindlehead 28, tool change arm 57 is rotated
counter clockwise about a 90 arc as illustrated in Fig. 20d
until cam plate lobe 365c (Fig. 19) abuts now-extended stop
member 300b (Figs. 16 and 19). When counter clockwise rotation
-38
of the tool chan~e arm is completed, proximity switch 360a
becomes actuated by virtue of finger 356b (Fig. 18) being in
proximity therewith. Upon actuation of proximity switch 360a,
the machine tool control system causes platform 46 to move
along ways 44 (Fig. 2) to move the tool change arm towards the
tool storage magazine. Following the movement of tower 46
along ways 44, pivot 53 and housing 55 are tilted 90 so as to
tilt the tool change arm, thereby allowing the toolholder or
multiple spindle presently gripped by jaws 338c and 338d to be
returned to the ready position of the tool change magazine.
Once pivot 53 and housing 55 have been tilted 90, so that
tool change arm 57 is now parallel to spindle bar 38 (as
illustrated in Fig. 2) then the conduction state of proximity
switches 316a and 316b reverses. Upon the reversal of the
conduction state of proximity switches 316a and 316b, tool
change arm carrier 50 is displaced downwardly to place the
toolholder or multiple spindle toolhead then enyaged by the
tool change arm in the tool storage disk pocket indexed to the
ready position. Once the tool change arm carrier has been
displaced downwardly, jaws 338c and 338d are biased apart to
release the toolholder or multiple spindle toolhead gripped
thereby causing the conduction state of proximity switches
360a and 360b to reverse.
The reversal of the conduction state of proximity switches
360a and 360b alerts the machine tool control system to dis-
place tower 46 forwardly on platform 43 away from the tool
storage magazine. Next, tool storage 60 is indexed to locate
the desired tool or multiple spindle toolholder at the ready
position. Once indexing of the tool storage magazine is
completed, tool change arm 57 transfers the newly indexed tool
or multiple spindle toolhead to the spindle as follows.
Eirstly, tower 46 is displaced rearwardly on platform 43 so
that jaws 338c and 338d circumscribe the tool now at the ready
position. Thereafter, the jaws are biased together to engage
the tool causing the conduction state of switches 360a and
360b to reverse which signals the machine tool control system
to displace tool change arm carrier 50 upwardly so that the
~2~L6~
-39- ,
shank of the toolholder or multiple spindle toolhead then
gripped by the tool change arm clears the tool storage magazine
pocket.
Following the upward movement of the tool change arm
carrier, housing 55 and tool change arm 57 are rotated by
rotary hydraulic actuator 54 (Fig. 11) to position the tool
change arm perpendicular to the spindle bar as shown in Fig.
11. Once the tool change arm reaches this vertical orientation,
the conduction state of proximity switches 314a and 314b
reverses.
The change in the conduction state of proximity switches
314a and 314b signals the machine tool control system to
extend spindle bar 38 if it is not already extended. Following
extension of the spindle bar, the machine tool control system
causes rotary hydraulic actuator 290 to rotate pivot 56 and
tool change arm 57 in a clockwise direction about an arc o
90 as illustrated in Eiy. 20e until cam plate lobe 365a abuts
stop members 300b and 300c. When rotation of the tool change
arm is completed, proximity switch 360d, which had b~en deac~
tuated, i5 now actuated, causing the machine tool control
system to displace platform 43 along ways 40 until jaws 338a
and 338b circumscribe the tool then in the spindle bar tool
receiving socket. Thereafter, the spindle draw bar is urged
forwardly to release the toolholder and then jaws 338a and
338b are biasad together to engage the toolholder or multiple
spindle toolhead then in the spindle bar. Once the jaws are
biased together, the conduction state of switches 360c and
360d reverse, signaling the control system to retract the
spindle bar and also to retract and advance stop members 300b
and 300a, respectively.
Upon the retraction and advancement of stop members 300b
and 300a, proximity switches 306b and 312b become actuated,
signaling the machine tool control system to cause rotary
hydraulic actuator 290 to rotate pivot 56 and tool change arm
57 in a counter clockwise direction about an arc of 180 as
illustrated in Fig. 20f so that jaws 338a and 338b are now to
~Z~6~
40-
the right of jaws 338a and 338b which now overlay the spindle
bar. When the rotation of tool change arm i~ completed, that
is to say, when cam pla-te lobe 365c abuts advanced stop member
300b, proximity switch 314a, which had previously been deactu-
ated, now becomes ackuated. This alerts the machine tool
control system to extend spindle bar 38 so that the fresh tool
engaged by jaws 338a and 338b is received within the spindle
bar tool receiving socket enabling the tool to be engaged when
draw rod 128 (Eig. 5) is rotatably threaded into the tool to
firmly urge it into the tool receiving socket 129.
The seating of the shank 139 of the single toolholder 58
in the socket 129 firmly secures the toolholder to the spindle
bar 38. In addition, the bar 38 includes a pair of diametri-
cally opposed keys 131 (one of which is shown in Figs. 5 and
21~ for engaging complementary keyways 135 formed in the
toolholders. The keys 131 serve to prevent any turning of the
toolholders relative to the spindle bar 38. Moreover (as
shown in Fig. 5), the retraction of the spindle bar 38 into
the spindle 34 operates to move the back face 366 of the
cutter 367 in the single toolholder 58 against the front face
368 of the nose of the spindle 34 to additionally support the
cutter and thus virtually eliminate cutter chatter even when
large diameter cutters 367 are being operated by the spindle
34.
Once the tool is firmly engaged in the spindle bar, then
jaws 338c and 338d are biased apart to release the toolholder
causing the conduction state of switches 360c and 360d to
reverse. The change in the conduction state of proximity
switches 360c and 360d signals the machine tool control system
to advance and retract stop members 3COb and 300a, respectively.
The advancement and retraction of stop members 300b and 300a,
respectively, causes proximity switches 306a and 312a to be
actuated, signaling the machine tool control system to displace
tower 46 away from upright 22. Once tower 46 is displaced
from upright 22, actuator 290 rotates tool change arm 57
counter clockwise about a 90 arc as illustrated in Fig. 20g,
until cam plate lobe 365b abuts stop members 300b and 300c.
12~
41-
By comparing Figs. 20a and 20g, it can be seen that the tool
change arm is now once again positioned to begin a tool change
cycle which is completed in exactly the same manner as des-
cribed above.
As was indicated earlier, when a multiple spindle toolhead,
such as multiple spindle toolhead 59 (Fig. 1) is transferred
from the tool storage magazine into the spindle by the tool
transfer arm, the spindle bar is retracted into the spindlehead
to urge the multiple spindle toolhead thereagainst, not only
to support the spindlehead, but also to prevent the body of
the spindlehead from rotating while the input shank of the
multiple spindle toolhead is driven by the spindle bar. The
details of how the multiple spindle toolhead engages the
spindlehead when urged thereagainst by virtue of the spindle
bar being retracted into the spindle are illustrat~d in Fig.
21. Referring now to that figure, it can be seen that each
multiple spindle toolhead, such as multiple spindle toolhead
59, has a plurality of locating pins 370 (only two of which
are shown) extending rearwardly from the body of the m~ltiple
spindle toolhead in spaced apart relationship about the multi-
ple spindle toolhead input shank 372. A plurality o~ comple-
mentary locating cones 374, corresponding in number to the
number of locating pins 370 extending from the body of the
multiple spindle toolhead, are spaced about the face of spindle
34 as illustrated in Eig. 1 so that each locatinq cone seats
in a complementary locating pin extending rearwardly from the
toolhead body when, following engagement by the spindle bar of
a multiple spindle toolhead, the spindle bar is retracted
rearwardly into the spindle to urge the multiple spindle
toolhead against the spindlehead. The locating cone and
locating pin arrangement described above, yields a simple, low
cost way to assure firm engagement between the spindle head of
a machine tool and the multiple spindle toolhead, thereby
eliminating the many disadvantages incurred by prior art
fastening schemes.
Figs. 22 and 23 illustrate the frontal and top or plan
views, respectively, of an alternate preferred embodiment 10'
6~1~
-42-
of a computer numerically controlled machining center having a
bar type spindle. Machining center 10' for the most part, has
the sàme structure ànd operates in the same fashion as machin-
ing center 10 of Figs. 1-3 and, therefore, like reference
numerals are employed in Figs. 22 and 23 to designate like
elements. Machining center 10' of Figs. 22 and ~3 does,
however, differ from machining center 10 of Figs. 1-3 in one
very important aspect. Tool storage magazine 60' of machining
center 10' of Figs. 22 and 23, which is configured of a plural
ity of parallel spaced apart disks 62 which are coaxially
mounted to shaft 61 just like tool storage magazine 60 of
Figs. 1-3, differs rom tool storage magazine 60 of Figs. 1-3
in that tool storage magazine 60' of machining center 10' of
Figs. 22 and 23, is removable from machining center 10' so as
to facilitate exchange of a complete tool storage magazine,
thereby greatly increasing machine tool flexibility.
Tool storage magazine 60' of machine tool 10' illustrated
in Figs. 22 and 23 has its shaft 61 vertically journaled in a
base 375 which is slidably mounted on a pair of ways 377 which
are fastened on saddle 16 parallel to ways 20 affixed on the
saddle. A combined shuttle and index mechanism (not shown)
such as ar~ well known in the art, is provided within bed 12
for displacing base 375 along ways 377 so as to shuttle the
tool storage magazine onto and off of the saddle. The shuttle
and index mechanism is further operative to index the tool
storage mechanism to locate a selected one of the tools verti-
cally stored therein in a ready position so as to enable
exchange of that tool with the spent tool into the spindle by
automatic tool changer 42.
Once the tool storage magazine is spent, it is shuttled
by the combined shuttle and index mechanism onto a nearby cart
380 which moves along a track 382 running along the side of
the machine tool parallel to ways 14a, 14b and 14c on machine
tool bed 12. As is best illustrated in Fig. 23, cart 380 has
a pair of tool storage magazine carriers 384a and 384b thereon
which are located at opposite ends of the cart. Each of tool
storage magazine carriers 384a and 384b is configured of a
-43-
platform 386 which overlies the cart so that the edge of the
platorm extends perpendicularly ~rom the cart almost to the
saddle 16 of machine tool 10' when cart 380 is moved along
track 382 so as to be adjacent to and parallel with bed 12 of
the machine tool. Each platform 386 carries a pair of parallel
spaced apart ways 388 thereon which are affixed to the platform
so as to be perpendicular to track 382. The spacing between
ways 388 on platform 386 is identical to the spacing between
ways 377 on base 375 so as to permit shuttling of a tool
storage magazine between the machine tool and the cart when
the cart is positioned along track 382 so as to be adjacent to
and parallel with the machine tool. In practice, cart 380
carries but a single tool storage magazine on one of the pair
of tool storage magazine carriers on the cart. In this way,
the empty tool storage magazina carrier on the cart can receive
the spent tool storage magazi~na when the cart is positioned so
that the empty tool storage magazine carrier is aligned with
ways 377 on saddle 16. Following shuttling of the spent tool
storage magazine onto the then-empty tool storage magazi~e
carrier, the cart is displaced on the track so that the tool
storage magazine carrier carrying the fresh tool storage
magazine thereon is aligned with ways 377 to permit shuttling
of the new tool storage maqaæine onto the machine tool saddle.
The foregoing describes a computer numerically controlled
machine tool whose spindle includes a bar having a tool receiv-
ing socket in the forward end thereof for engaging either a
multiple spindle toolhead or a single toolholder. The bar is
extendable from the spindle for engaging a toolholder from the
automatic tool chan~e mechanism and for facilltating a deep
boring or drilling operation. The bar is also retractable
into the spindle to urge a multiple spindle toolhead against
the machine tool to provide firm support therefor.
Although the illustrative embodiments o the invention
have been described in considerable detail for the purpose of
fully disclosing a practical operative structure incorporating
the invention, it is to be understood that the particular
apparatus shown and described is intended to be illustrative
6~
-44-
only and that various novel features of the invention may be
incorporated in other structural forms without departing from
the spirit and scope of the invention as defined in the sub-
joined claims.
