Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to automatic tool changer
for machine tools.
This applic~tion is a division of C~nadian P2tent
Application Serial Number 337,783, filed October 17, 1979.
In the past, many different types of automatic
tool changers have been built, including some tool changers
which are adapted to handle either single tools or small
multiple spindle toolheads, but not large multiple spindle
toolheads. ;
The principle object of this invention is to pro- ;
vide a novel multiple spindle toolhead for an automatic
tool changing machine tool which is adapted to handle
single tools. It is yet another object of the present
invention to provide improved means for securing a multiple
spindle toolhead adjacent to the spindle of an automatic
tool changing machine tool. Other objects and advantages
of the invention will be apparent from the detailed des-
cription herein.
The present invention provides a multiple spindle
toolhead for use on an automatic tool changing machine
tool and comprises a body having an input shank journaled
into the back of the body and extending therebeyond for
insertion into the machine tool spindle. At least one
tool-carrying spindle is journaled into the body and is
coupled to the input shaft by means of gears or the like.
To secure the spindle head to the machine tool during a
machining opera}ion, a plurality of threaded studs are
fastened to a flange which is fastened to the body to
circumscribe the input shank. The flange has a groove
therein for so as to permit engagement with the tool gripper
arm of the automatic tool changer. Each of the threaded
studs extending from the flange is dimension complementary
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to a corresponding one of a plurality of threaded collars
located in the machine tool adjacent to the spindle. In
practice a portion of each threaded stud and a portion of
each threaded collar is recessed so that when the tool
holder is inserted into the spindle, the threads on each
threaded stud are in juxtaposition with the threads on a
corresponding collar, permitting the threads on each stud
to engage the threads on each collar when each collar is
rotated relative to each stud.
In the drawing:
Figure 1 is a front elevational view of a horizontal
machining center which utili~es an automatic tool changer
of this invention;
Fig. 2 is a plan view of the machining center
of Fig. l;
Fig. 3 is a plan view of the tool storage magazine;
Fig. 4 is a fragmentary plan view of one end of
the tool storage magazine;
Fig. 5 is a side elevational view taken on the
line 5-5 of Fig. 3;
Fig. 6 is a cross sectional view taken on the
line 6-6 of Fig. 3;
Fig. 7 is a cross sectional view taken on the
line 7-7 of Fig. 3;
Fig. 8 is a longitudinal sectional view taken
on the line 8-8 of Fig. 4;
Fig. 9 is a cross sectional view of a tool socket
taken on the line 9-9 of Fig. 3;
Fig. 10 is a plan view of the tool change arm
which transfers tools and toolheads from the tool storage
magazine to the tilt unit and vice versa;
Fig. 11 is a radial sectional view taken on the
line 11-11 of F'ig. 10;
Fig. 12 is a fragmentary longitudinal sectional
view taken on the line 12-12 of Fig. 11;
Fig. 13 is a cross sectional view taken on the
line 13-13 of Fig. 11;
Fig. 14 is a cross sectional view taken on the
line 14-14 of Fig. 11;
Fig. 15 ls a front elevational view of the tool change
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arm of Fi~. 10;
Fig. 16 is a rear elevational view of the upright
which supports the tool change arm of Fig. 10;
Fig. 17 is a side elevational view of the upright
which supports the tool change arm of Fig. 10;
Fig. 18 is a side elevational vlew of the tilt unit;
Fig. 19 is a pl~n view of the tilt unit;
Fig. 20 is a front elevational view of the tilt unit;
Fig. 21 i5 a fragmentary plan view, partially cut a-
way, of the tool change arm which trans~ers tools and toolheads ;~between the tilt unit and the spindle of the machining center;
Fig. 22 is a rear elevational view taken on the line
22-22 of Fig. 21;
Fig. 23 is a fragmentary plan view) partially cut a
way, of the tool chan~e housing adjacent to the spindle of the
machining center;
Fig. 24 is a cross sectional view taken on the line
2"-24 of Fig. 21;
Fig. 25 is a front elevational view of the tool
change arm of Fig. 21 with the front cover cut away and the arm
in its vertical position;
Fig. 26 is a front elevatlonal view of the tool
change arm of Fig. 21 with the Eront cover cut away and the arm
in its horizontal position;
Fig. 27 is an axial sectional view of the spindle;
Fig. 28 is a fragmentary plan view of the tool change
housing ad~acent to the spindle of the machine tool;
Fig. 29 is a fragmentary front elevational view taken
on the line 29-29 of Fig. 28;
Fig. 30 is a cross sectional view taken on the line
30-30 of Fig. 28;
Fig. 31 is a fragmentary longitudinal sectional view
taken on the line 31~31 of Fig. 25;
Fig. 32 is a fragmentary cross sectional view taken
on the line 32-32 of Fi~. 31;
Fig. 33 is a longitudinal sectional view of a multiple
spindle toolhead mounted in the machine tool spindle;
Fig. 34 is a longitudinal sectional view of the sup
~" port and ^lamp means on the spi.ndlehead for clamping a toolhead
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thereto and for supporting the toolhead;
Fig. 35 is a fragmentary ~ront elevatlonal vLew taken
on the line 35-35 of Fig. 34;
Fig. 36 is an end view of a threaded stud which pro-
~ects from th~ rear Or the multlple spindle toolhead shown in
Fig. 33;
Fig. 37 is a fragmentary plan view taken on the line
37-37 of Fig. 3~1;
Fi~. 38 is an exploded perspective view of one o~
the studs which form part of the clamp and support means for
the multiple spindle toolhead;
Fig. 39 is a side elevational view of a boring bar
adapted to be used in the machine tool and automatic tool changer
of this invention; and
Fig. L~o is a block diagram of the electrical circuits
which control the machine tool and automatic tool changer of
this invention.
Figure 1 is a front elevational view and Fig. 2 is
a plan view of a horiæontal machining center which is equipped
~ith an automatic tool changer o~ this invention. The machining
center includes a bed 50 upon which a saddle 52 is slidably
mounted on X-axis ways 5L~ (Fig. 2). Saddle 52 is driven along
ways 54 by a rack and pinion drive which consists of a rack 56
(Fig. 2) on bed 50 and two pinions 58 on saddle 52 which are
driven by a servo motor 60 through a conventional speed reduction
gear box 62. Motor 60 is selectively energized by a conventional
numerically controlled X-axis servo system (not shown) to move
saddle 52 to any desired position along the X-axis.
A pair of flexible metallic cover sheets 53 are coupled
between opposite side edges of saddle 52 and a corresponding pair
of storage rollers 55 which are mounted on opposite ends of bed 50.
Cover sheets 53 are both made of relatively narrow interlocked
metal slats S7 (Fig. 2) and easily roll up on thelr respective
rollers 55. Both rollers 55 are torsion biased away from saddle
52 by motors 59 (Fig. 1) and maintain a tension in cover sheets
53 at all times so that each cover sheet 53 will roll up auto-
matically when saddle 52 moves toward it while the opposing cover
sheet 53 will be drawn off its roller 55 agains-t the ~orce o~ the
- corresponding motor 59. Cover sheets 53 protect the portions o~
X-axis ways 54 that are not covered by saddle 52.
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A set of Z-axis ways 64 are formed on top of saddle
52 perpendicular to X-axis ways 54. An upright 66 is slidably
mounted on Z-axLs ways 64 and is driven there along by A con- ,
ventional balls~rew drive (not shown) which 1s powered by a '-
servo motor 6~ (Flg. 2). Motor 68 is selectively energized
by a conventional numerically controlled Z-axis servo system
(not shown) to move upright 66 to any desired position along
the Z-axis.
A set of vertical Y-axis ways 70 are formed ~n upright
66 perpendicular to both X-axis ways 5l~ and Z-axis ways 64. A
spindlehead 72 is slidably mounted on Y-axis ways 70 and is
driven there along by a conventional ballscrew drive (not
shown) which is powered by a servo motor 74 (Fig. 2). Motor
74 is sele~tively energized by a conventional numerically con-
trolled Y-axis servo system (not sho~n) to move spindlehead 72
to any desired p~sition along the Y-axis.
A hydraulically actuated counterweight system is
coupled to spindlehead 72 to take the weight of spindlehead
72 off the ballscrew drive therefor. The counterweight system
in^ludes two hydraulic piston and cylinder mechanisms 76 (Fig.
1), two cables 78 which are coupled between hydrauli,c cylinder
mechani~ms 76 and spindlehead 72~ and pulleys ~0 which guide
cables 78. Hydraullc piston and cylinder mechanisms 76 apply
a tension to cables 7~ which is approximately equal and opposite
to the weight of spindlehead 72 to take the weight of spindle-
head 72 off the ballscrew drive.
A spindle 82 is rotatably mounted in spindlehead 72
and is adapted to receive conventional cylindrical shank tool-,
holders and to clamp the toolholders to spindle 82 for rotation
3o therewith. Spindle 82 is driven in its rotary motion by a
spindle motor 84 (Fig. 2) through a set of conventional speed
change gears (Fig. 27). Motor 8LI is sele^tively energized by
a conventional numerically controlled spindle motor control
(Fig. 40) to rotate spindle 82 at the desired sp,eed in the de-
sired direction to machine a work-piece ~6 (Fig. 2) on a con-
ventional worktable 88 positioned in front of' bed 50. The de-
tails of worktable 88 are omitted since they are not relevant to
the automatic tool changer of this invention.
The automatic tool changer includes (1) a double
deck tool stora~,e magazine 90 which is adapted to store a
plurality of single tools a,ld/or multip1e spindle toolheads
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with the shanks thereof in a vertical posLtion, (2) a tilt
unit 92 which is adapted to hold one toolhead and to tilt
the tool or toolhead by 90 from a vertical position to a
horiæontal position parallel to the axis of splndle 82 or
from a horizontal position to a vertical position, (3) a
first tool change arm ~ssembly 94 which is adapted to trans-
fer tools and toolheads between tool storage magaæine 90 and
tilt unit 92, (4) a second tool change arm assembly 96 which
is adapted to transfer tools ancl toolheads between tilt unit
92 and spindle 82, (5) coacting clamp and support means,
described hereinafter~ for supporting each multiple spindle
toolhead and holding it stationary while the shank and tools
thereof are rotating with spindle 82, and (6) the hydraulic
and electrical controls~ described hereinafter, required to
move the movable portions of components (1) to (5) above in
accordan^e with a predetermined sequence~ described hereinafter,
for transferring tools and/or toolheads from tool storage maga-
zine 90 to spindle 82 and vice versa.
The individual components o~ the automatic tool
changer will be described in detail starting with tool storage
magazine 90. Tool stora~e magazine 90 is a double deck strus-
ture which supports two endless chains 98 (Fig. 2) of tool and/
or toolhead sockets 100. Referring to Fig. 9, each tool socket
100 has a hollow cylindrical body 102 which has a central bore
104 which is of a size to receive relatively large single tools
with cylindrical shank toolholders or relatively large multlple
spindle toolheads with cylindrical shanks. A flange 106 i5
formed on the top of body 102 for supporting the flange 108
on a toolholder or toolhead whose shank is inserted in bore 104
Tool so_ket body 102 is bolted to a carrier 110 by
bolts 112. Carrier 110 is fastened to chain 98 by a pair
of support pins 114 ~hich are fastened together on their top
end by piece 116 and extend through adJacent openings in
the links of chain 98. A snap fastener 118 enga~es the bot~
tom of oins 114 and secures them to chain 98.
At the bottom of tool so~ket body 102, three rollers
120 (Fig. 6) are ~ournaled to flan~es 122 with two rollers
120 on the outer side o~ socket body 102 (to the right in
Fig. 6) and one roller in the inner side (to the left in Fig. 6).
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Rollers 120 ride in covered channels formed by spaced plates
124 and 126 which are ~astened together by conventional means
and are supported by conventional means.
Referring to Fig. 3, both endless chains 98 are
guided and driven around a double L-shaped path by means of
conventional sprockets, one of which is sho~n in ~ig. 6, and
another of which ls shown in Fig. 7. Sprocket 128 in Fig. 6
is journaled for rotation on a vertical axle 129 between two
spaced support plates 126 and 130 by conventional means and
is driven by a servo motor 132 which is also attashed to
plates 126 and 130 by conventional means. Servo motor 132
drives a pinion 134 which is meshed with drive sprocket 128.
Sprocket 136 in Fig. 7 is an idler sprocket which is
journaled for rotation on a vertical axle 13~ bet~een spaced
sup~ort plates 126 and 130.
On the bottom of sprocket 136 (Fig. 7), a plurallty
of radially spaced stop lugs 140 are bolted thereto as a means
of counting and locating the tool sockets 100. Stop lugs 140
are spaced apart fro~ eaeh other by the radial angle that
separates tool sockets 100. A first proximity s~ltch 142 is
mounted on plate 130 and produces an output signal whenever one
of the lugs 1~0 passes over it. A second proximity switch 144
(Fig. 6) is clamped to plate 124 in position to coact with a
downwardly projecting tab 146 on one of the tool sockets 100.
Proximity switches 142 and 144 keep track of which
tool socket 100 is in position to trans~er or receive a tool.
The tool sockets 100 in the upper deck of this embodiment o~
the invention are numbered from 1 to 29. When there is an out-
put signal from both proximity switches 1~2 and 144, tool socket
3 number 1 is in position to transfer or receive a tool. Each
subsequent output signal from proximity switch 142 means that
the next tool socket 100 in the sequence is in position to trans-
fer a tool
When the desired tool socket 100 is in position, motor
132 (Fig. 6) is de-energized and chain 98 coasts to a stop. A
precisien locating stud 148 (Fig. 7) is then raised by a hydraulic
piston and cylinder mechanism 150 into position to engage the near-
est lug 140. Motor 132 is then energized in the reverse direction
to back sprocket 136 up until lu~ 140 and locating stud 148 abut
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agains-t each other as shown in Fig. 7 which locates the
desired tool socket 100 in position to transfer or recelve a
tool. Locating stud 14~ ls slidably mounted in a housine 149
and is moved by hydraulic piston and cylinder mechanism 150
between an upper position, sho~n in Fig. 7, and in which stud
148 abuts against the a~jacent stop lug 140, and a lower posi-
tic,n, in which stud 148 clears stop lugs 140. Stud 148 is
moved to its lower posltion before motor 132 is energized in
the forward direction to move a di~ferent tool socket 100 into
the tool transfer position.
The tension in chain 98 is adjusted by an adjustable
idler sprocket 152 ~Fig. 8) which is journaled on a vertical
axle 154 in bearing housings 155 which are slidably mounted
on plates 126 and 130 by conventional means. A pair of
threaded sttids 156 carrying adjustment stop nuts 158 are screwed
into threaded openings in housings 1~5. Stop nuts 158 abut
- against slotted lugs 160 on plates 126 and 130. The tension
in chain 98 can be adjusted by loosening or tightening nuts 158.
Fig. 5 shows the supporting structure for tool storage
magazine 90. The rear portion of tool storage magazine 90 (at
the right side of Fig. 5) is rollably supported on a stationary
rail 162 by rollers 164 which are journaled to a base 166. Base
166 is attached to the lower plate 130 of the lo~er deck o~ tool
storage magazine 90. A group of spaced posts 16~ extend between
the lower plate 130 of the lower deck and the lower plate 130 of
the upper deck of tool storage magazine 90. The front portion
of tool storage magazine 90 (at the left side of Fig. 5) is
slidably supported on bases 170 which extend from the ad~acent
portion of X-a~is bed S (Fig. 1). A base plate 172 is attached
to the adjacent end of the saddle 52 and slides over bases 170.
The front portion of tool magazine 90 is supported by base plate
172 and thus moves with saddle 52 over the X-axis bed 50 and bases
170~ Base plate 172 also supports tool change arms 94 and 96
and tilt unit 92 (see Fig. 2). Thus upright 66, tool storage
magaz~ne 90, tool change arms 94 and 96 and tilt unit 92 all
move as a unit with saddle 52.
Referring to Fig. 2, a first tool change arm assembly
94 transfers tools from tool storage magazine 90 to tilt unit 92.
The details of the first ool change arm assembly 94 are illustrated
in Figs. 10-17. Referring to Figs~ 10 and 11, a tool gripper arm
174 is rotatably mounted on a base 176 for rotation about a vertlca:
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-- a~is 17~ g. i.1). Tool ~ripper arm 17~-~ is rotatabl~ from a
forward position, inclicated in Flg. 10 by broken ou~line 174A,
to a central position ind1cated in Fi~ by the solid outline
17l~B, to a rear posi.tion indis~a~ed in Fig. 10 b~ bro'~erl outline
174C. In the rear positlon, tool gri~per arm 17l~ picks up a tool
or tool.head from tool storage Magazine 90. In the central position,
the tool or toolhead is placed in tilt unit 92 In the forward
position, tool ~ripper arm 174 is clear of tilt unit 92 so that
the latter.can tilt ~orward. On the return portion of the cycle~
tool gripper arm 174 picks up a tool or toolhead from tilt unit
92 in the central posi.tion and t:rans~ers it -to tool stora~e mag
azine 90 in the rear posLtion.
Tool gripper arm 174 is rigi.dly attached to a vertical
shaft 184 (Fig. 11) which is rotatably attached to brackets 186
on base 176 by bearings 1~8. A horizontal bracket 190 is ro-
tatably atta^hed to shaft 1~4 by bearings 192 and is moved by a
hydraulic piston and cylinder mechanism 194 (Fig. 10) which, in
its retracted position, moves arm 174 to its forward position, and
which in its extended position, moves arm 174 fro~ its forward pos-
ition to its central position. The piston rod 195 of hydraulicpiston and cylinder me_hanism 194 is connected to bracket 190 by a
pivotal connector 1~. The other end of hydraulic piston and cy-
linder mechanism 194 is pivotally connecteA to a bracket 198 on
base 176.
A bra^ket 200 (Fig. 11) is attached to a projection 201
of bracket 190 by machine screws 203. Bracket 200 provides a piv-
otal mountlng for another hydraulic plston and cylinder mechanism
202 which is pivotally coupled between brackets 190 and 200 by
trunnions 204 (Fig. 15). The piston rod 206 (Fig. 15) of hydraulic
3 piston and cylinder mechanism 202 is pivotally coupled to a bra_ket:
20~.(Fie. 11) on tool ~ripper arm 174 by a pivotal connector 210.
~Iydraulic piston and cyli.nder mechanism 202, when extended, moves
arm 174 ~rom its central position 174B (Fig. 10) to its rear posi-
tion, indicated by broken line outline 174C in Fig. 10. When
hydraulic piston and cylinder mechanism 202 is retracted, it moves
arm 174 from i.ts rear posi.tlon 174 C to its central position, in-
dicated by the solid line position 174B in Fig. 10. A pair o~ cam
actuated limit switches 212 and 21l~ (Figs. 11 and 15) indicate when
ar~ 174 is in the forward, central, or rear position. I.imit switch
212 is actuated by cam 216 and limit s~litch 21)~ is actuated by cam
21~. Both cams 216 and 218 are mounted on a shaft 219 whi_h is
attacheA to shaf-t 184.
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A semicircular gripper cavity 220 (Fig. 10) is formed
in the en~ o~ arm 17~. A pair of rollers 222 and a movable ~aw
member 224 are movably mounted in arm 174 and are positioned
around gripper cavity 220 in position to grip the grooved ~lange
of a toolholder or multiple spindle toolhead to securely hold the
toolholder or toolhead in arm 174 for transfer. Movable Jaw member
224 is slidable in slot 226 in arm 174 between an extended position
shown in Fig. 10 and a retracted position (not shown) in which
jaw member 224 is completely withdrawn into slot 226. Jaw member
10 224 is moved back and forth between its extended and retracted
positions by a hydraulic piston and cylinder mechanism 228 which
moves a slide 230 in a slot 231 ~Fig. 12) crossways of jaw member
224. Slide 230 has a raised cam portion 232 (Fig. 12) which ex-
tends at a 45 angle ;~ to the edge of slide 230 and slidably en-
gages a cam slot 234 in ~aw 224. Cam slot 23l~ extends at the same
angle~o~ 45 to the edge of jaw member 224 and interacts with the
raised cam portion 232 o~ slide 230 to move ~aw member 224 between
its extended and retracted position.
When hydraulic piston and cylinder mechanism 228 is
20 extended, ~aw member 224 1s retracted and when hydraulic piston
and cylinder mechanism 228 is retracted, as shown in Fig. 12,
jaw ~ember 224 is extended.
The tlp 236 (Fig. 12) of cam portion 232 and the ad-
jacent portion of slot 234 are angled at a small angle~S to the
edge of slide 230 to provide for a reduced rate o~ movement at the
end of the retraction stroke of hydraulic piston and cylinder mech-
anism 228 to lock the toolholder or multiple spindle toolhead in
gripper jaw cavity 220. Movement of cam portion 232 along the edge
236 will continue until ~aw member 224 exerts enough pressure on the
3o toolholder or toolhead therein to counteract the retraction force
of hydraulic piston and cylinder mechanism 228.
Referring to Figs. 11, 13 and 14, the bottom of slot
226 in tool gripper arm 17l~ is closed by a cover plate 238 which
is attached to gripper arm 174 by machine screws ?40. The end of
slot 231 is closed by a cover plate 242 (Fig. 13) which is attached
~o gripper arm 174 by machine screws 244. A limit swltch 246
(Figs. 11 and 14) is mounted on the bottom of cover plate 238 by
machine screws 2l~8. A spring loaded plunger 250 (Fig. 1ll) bears
against the bottom of gripper jaw 224 and actuates switch 246
when gripper jaw 224 is in its retracted positinn.
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Tool gripper base 176 is slidably mounted for vertical
movement on an upright 252 (Figs. 10, 16 and 17). A set of
vertical ways 254 (Figs. 10, 15 and 17) are formed on upright
252 to guide the vertical movement of tool gripper base 176.
Two vertical movements are required for base 176. The first is
a short upward movement to ]ift a toolholder or toDlhead from
the tool storage socket 100 with which tool gripper arm 174
is aligned, along with the complementary short downward movement
to lower a toolholder or toolhead intD the tool storage socket
100. The second vertical movement is a longer upward movement to
raise tool ~ripper arm 174 from the lower deck of tool storage
magazine 90 to the upper deck thereof, along with the complementary
downward movement to lower tool gripper arm 174 from the top deck
to the lower deck.
These two movements are obtalned by two hydraulic
piston and cylinder mechanisms 256 and 258 (Fig. 16) which are
connected together in tandemJ the base of the longer cylinder 258
being connected to, and supported by, the end of the piston rod
of the shorter piston and cylinder mechanism 256. The end of the
piston rod 260 of the longer piston and cylinder mechanism 258 is
attached to a bracket 262 on the top o~ tool gripper base 176 by
a machine screw 264 (Figs. 15 and 16). Figs. 16 and 17 show the
longer piston and cylinder mechanism 25~ in its fully extended pos-
ition and the shorter piston and cylinder mechanism 256 in its
fully retracted position. This places tool gripper arm 174 in
position to pick up a tool or toolhead from the upper deck of
tool storage magazine 90. After the tool or toolhead has been
gripped by gripper arm 174J it is lifted out of its socket 100 by
extension of piston and cylinder mechanism 256. Then, after tool
3 ~ripper arm 174 has been swung clear of tool storage magazine 90,
both piston and cylinder mechanisms 256 and 258 are retracted to
drop the tool or toolhead into tilt unit 92.
With both piston and cylinder mechanisms 256 and 258
retracted~ tool gripper arm 174 is vertically positioned to grip
a toolholder or toolhead in the lower declc of tool storage magazin~
90. An extension o~ piston and cylinder me~hanism 256 will then
lift the gripped toolholder or toolhead out of its socket 100. Th~
tool gripper arm 174 is then swung over tilt unit 92 (see Fig. 2)
and piston and cylinder mechanism 256 is retracted to drop the too~
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holder or tool head into tilt unlt 92.
Four limit switches 266, 26~, 270, and 272 ~Fig. 17) are
mounted on upright 252 and interact with the ad,~acent edge of
tool gripper base 176 to indicate which of the four possible
vertical positions that base 176 is in at any time.
~ Figs. 18, 19 and 20 show the details of tilt unit
- 92. A cylindrical tool socket 274 having an axis 275 (Fig. 18)
is attached to an arm 276 which is pivotally attached to a pair
of upstanding triangular sides 27~ by trunnions 280. Triangular
sides 278 are bolted to a base pla,te 282.
Socket 274 can be pivoted from a vertical position,
shown in solid lines in Fig. 1~, to a horizontal posltion,
shown in bro~en lines in Fig. 18, by extension and retraction
of two hydraulic piston and cylinder mechanisms 284 which are
each pivotally connected at one end to base plate 282 and are
pivotally connected at the other end to socket 274. Within socket
274, a hollow cylindrical collet clamp 286 is slidably mounted
on a shaft 288. A stack of Belleville springs 290 spring ~ias
collet clamp 286 to its clamped position. A short hydraulic pis-
ton and cylinder mechansim 292 is mounted on the bottom of socket274 in position for its piston rod 293 to bear against the end of
shaft 288 to move collet clamp 286 to its unclamped position~
Collet ^lamp 286 serves to clamp ~he cylindrical shank of a
toolholder or multiple spindle toolhead in socket 274.
A conventiorlal cam operated limit switch 29l' (Fig.
1~) is mounted on one of the triangular sides 278 and is actuated ,,
by cam 296 to indicate whether socket 274 is in its vertical or
horlzontal position.
Figs. 21 to 26 illustrate the details of the second
too,l change arm assembly 96 (Fig. 2) which exchanges tools or
toolheads between tilt unit 92 and spindle 82. Tool change
arm assembly 96 has a double ended tool gripper arm 298 which
is rotatably mounted in an upright 300. Arm 29~ is rigidly
attached to a hollow shaft 302 (Fig. 21) which is rotatably
mounted in upright 300 by conventional means (not shown) and is '~
slidable along i.ts axis to ~ove arm 298 between a rear position
shown in solid lines in Fig. 21 and a forward position shown in
broken llnes in Fig. 21.
Shaft 302 is circumferentially slotted at 304 to re-
ceive a pair of rollers 306 (Figs. 21 and 24) which are mounted
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on a yoke 308 Yoke 308 is moved back an~ forth (right
and left in Fig. 21) by a hydraulic piston and cylinder
mechanism 310 whose plston rod 312 is rigidly attached to
yoke 308. When piston rod 312 is extended, it moves arm 298
to the rear position shown by solid lines in Fig. 21. When
piston rod 312 is retracted, it moves arm 298 to the forward
position shown by broken lines in F`ig. 21 The ~orce of pis-
ton 312 is communicated to shaft 302 through yoke 308 and
rollers 306, which allow arm 298 to rotate in either its for~
ward or rear positions.
A spur gear 314 (Figs. 21 and 22) is rigidly at-
tached to the rear end of shaft 302 and engages a rack 316
(Fig. 22~ when shaft 302 is in its rear position, shown by
solid lines in Fig. 21. Rack 316 is moved up and down by a
hydraulic piston and cylinder mechanism 318 whose piston rod
320 is attached to rack 316 and whose cylinder is attached
to a bracket 322 on upright 300 by machine screws 324. The
full stroke of rack 316 rotates shaft 302 through 90 to
rotate arm 29~ from its vertical position (shown in Figs.
20 1, 21 ancl 25) to its horizontal position (shown in Fig. 26).
The vertical positLon of arm 298 is the stand-by position and
the horizontal position is the tool pick up or deposit position.
When shaft 302 and arm 298 are ln their forward posi-
tion) shown by broken lines in Fig. 21, gear 314 is aligned
with a se^ond rack 325 (~igs. 21 and 23) which is moved by a
hydraulic piston and cylinder mechanism 326. The piston rod
328 of piston and cylinder mechanism 326 is attached to rack
325, which is twice as long as rack 316 and rotates shaft
302 and arm 298 by 180~ to interchange the ends thereof. The
30 rotation through 180 only occurs when shaft 302 and arm 298
are in their forward position, shown by the broken lines in
Fig. 21.
Limit switches 330 and 332 (Fig. 21) are mounted on
upright 300 by conventional means and are actuated by plungers
334 and 336 to indicate whether arm 298 is in the forward or
rear position. A limit switch 338 is mounted on the housing 340
for rack 325 and interacts with a plunger 342 to indicate whether
arm 298 is in a position to pick up tools or toolheads or to
deposit tools or toolheads.
Tool gripper arm 298 (Figs. 25 and 26) has opposed
tool gripper cavities 344 and 346 which contain rollers 348
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- 14
Rollers 34~ are dimensioned and positioned to fit in a stand-
ard grooved flange on a toolholder or multiple spLndle tool-
heaA. A pair of rotary tool gripper ~jaws 350 and 352 are
rotatably attached to arm ~9B adjacent to grlpper cavities
344 and 34~. Tool gripper ~aws 350 and 352 have ~ripping
segments 354 and 356, respectively, which are shaped to enter
the groove~ flange on a tnolholder or multiple spindle tool-
head. Grlpper ~aws 350 and 352 are sprlng biased by torsion
springs 358 (Figs. 31 and 32) to ur~e gripping segments 354
and 356 away from tool cavities 3L14 and 346, respectively.
The mov~ment of gripping segments 354 and 356 away from tool
cavities 344 and 346 is limited by the abutment of the straight
edges 370 and 372 of ~ripper jaws 350 and 352 with stop pins 362
and 364, respectively.
A-cam 360 with an open position shown in solid lines
- in F g. 25 and a locked position shown in broken lines in Fig. 25
is rotatably mollnted between gripper ~aws 350 and 352. In the
locked position shown in Fi~. 26, both gripper ~aws 350 anA
352 are rotated toward their respective tool cavitles 344 and 346
to insert tool grip segments 354 and 356 into the grooved flange
of toolholders 366 and 368, res~pectively. In the position shown
in Fig. 26, both tool gripper jaws 350 and 352 are locked in the
position shown by cam 360~ ~hich abuts against the straight edges
370 and 372 on jaws 350 and 352, respectively. This locks tool-
holders 366 and 368 in tool cavities 344 and 346, respectively.
Cam 360 is mounted to be able to flaot laterally to equalize
calmping pressure. To release toolholder 366 and 36~, cam 360
must he rotated 90 degrees counterclockwise from the position
shown in Fig. 26 back to the position shown in solid lines in
3o Flg. 25. This permits tool gripper ~aws 350 and 352 to rotate
counterclockwise in Fig. 26 away from tool cavities 344 and 346,
respectively.
Referring to Figs. 21 and 26, cam 360 is attached to a
sha~t 374 (Fi~. 21) which extends through the hollow interior
of shaft 302. The rear end of shaft 374 (on the right side of
Fig. 21) is connected to a hydraulic rotary actuator 376 such
as manu;actured by the Flo-Tork Company, Oville, Ohio, U.~.A.
Rotary actuator 376 ac-ts to rotate shaft 374 by 90 clockwise
or counterclockwise in response to electrical signals 90
rotation of shaft 374 rotates cam 360 between its open and lockeA
: . -; ; . :: '
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Z46
- 15
position as des_ribed previously.
Toolhol~r 366 in Fig. 25 is in spindle 82 whlle tool-
holder 368 is in tilt unit 92. To exchange toolholders 366 and
368, upright 66, saddle 52 and spindlehead 72 are moved by the
N.C. axis servo systems to the positions shown ln Figs. 1 and 2.
Tool change arm 298 ls then rotated 90 counterclockwise from
the position shown in Figs. 1 and 25 to the position shown in
Fig. 26. As tool cavities 344 and 346 approach toolholders
3~6 (Fig. 25) and 368~ the latter contact flat edges 378 and 380
of gripper jaws 350 and 352 and cause them to rotate to move
gripper segments 354 and 356 into the grooved flange of tool-
holders 366 and 368. Gripper segments 354 and 356 are then
locked in position by rotating cam 360 by 90 counterclockwise
to the position shown in ~ig. 26.
To unlock gripper jaws 350 and 352, cam 360 is ro-
tated 90 counterclockwise in Fig. 26, which releases grip-
per jaws 350 and 352 to rotate away from toolholders 366
and 368 under the ur~ing of their respective torsion springs
353 (Figs. 31 and 32).
Although the operation of tool change arm 298 has
been described in connection with tools on both ends of the arm~
it will work as well with a single tool at either end of the
arm.
Referring to Flg. 27, spindle 82 is rotatably mounted
t~ithin spindlehead 72 by bearings 384 and is driven by a con-
ventional speed change gear set 386. Spindle 82 is hollow and
contains a drawbolt 388 rotatably mounted therein and adapted
to be rotated by a conventional drawbolt motor and clutch ar-
rangement which are not shown in the drawings. Drawbolt 388 is
3 threaded at its front end 390 to fit into a threaded opening
in the cylindrical end of a toolholder or multiple spindle tool-
head,
A collet clamp 392 with a cylindrical socket is at-
tached to the front end of a hollow collet tube 394 which lies
within the hollow interior o~ spindle 82 and encloses drawbolt
388. ~ollet tube 394 is axially slidable with respect to spindle
82 and drawbolt 388 and is axially sh`ifted between an open and
a clamped position of collet 392 by a hydraulic piston and cylinde
~-' mechanism 396 (on the right side of ~ig. 27), The piston rod 398
. ~ : . :
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of piston and cylinder mechanlsm 396 acts on a lever arm
400 which is pivotally connected to spindleheacl 72 by pin
402 ancl has a cam 404 which pushes or pulls on collet tube
394 when lever arm l~oo is rocked by hydraulic pistnn and
cylinder mechanism 396. ~ollet clamp 3~2 clamps the toolholder
shank or toolhead shank to spindle 82 to prevenl; the toolholder
from being dislod~ed when drawbolt 388 is screwed thereinto.
Collet clamp 392 a.lso centers the to~lh~lder shank,
A novel clamp and support means is used to clarnp
relatively heavy (e.~ 000 pounds) multiple spindle tool-
heads 405 (Fig. 33~ to spindlehead 72 to support the tool-
head 405 and hold it stationary while its shank l~o6 and
tools 408 are rotating with spindle 82.
Toolhead 405 has a body 497 in which a plurality of
spindles 49~3 are ~ournaled. Spindles 498 are rotated by con-
ventional gears 499 which are couple~ between spindles 49~ and shank
~o6, which is journaled in body 497 and I`lange block 503 by bear-
ings 500. Body 497 has a backplate 501 with a central opening
502 through which shank 406 passes.
A flan~e block 503 is attached to backplate 501 by
bolts 5Q4 and extends rearwardly from backplate 501. Flange
block 503 is ^ylindrical in shape and has the same outside
diarLeter as the flange 448 (Fig. 39) of an individual tool-
h~lder which is dimensioned to be gripped by the tool changer
arms 174 (Fig. 1) and 298 described previously. Flanges 448
and 503 have V-grooves 450 (Fig. 39) and 452 (Fig. 33) which
have the same dimensions and are dimensioned to be gripped by
the above-noted tool changer arms 174 and 29~. Flange block
503 has a rear flange on the rear portion thereof for supporting
toolhead 405 as described below.
Four threaded studs 410, each having two opposed
flats 412 (Figs. 36 and 38) ground on its threaded end, are
rigidly attached to circumferentially spaced openings 414 in
rear flange 416 (Fig. 33) of each multiple spindle toolhead
405. Fig. 3~3 shows a perspective view of one of the studs 410.
The head 41~3 of stud 410 is oblong in shape and has two holes
420 for receiving ma^hine screws 422 (not visible in Fig. 33)
which rigidly fasten stud 410 to flange 416. Although only one
stud 410 is vLsible in Fig. 33J it will be understood that the
other three are positioned at circurnferential posit,ions that are
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2~6
not cut by the plane of Fig. 33.
A guide pin 424 (Fig. 33) whlch is attached by con-
ventional means to flange 416 coacts with a guide openin~ 4~6
in spindlehead 72 to correctly align studs 410 with the threaded
openlngs 428 (Fi~,. 35) into which stu~s 410 are inserted. Open-
ings 428 have slotted sides 430 which receive the threaded por~
tions of studs 410 while the flats 412 of stud 410 pass by the
thrcaded portions of opening 428. Threaded openings 1~28 are
each formed in a collar 432 which is rotatably attached to
spindlehead 72 (Fig. 33). Each stud 410 is locked in the cor-
responding collar 432 by rotating collar 432 by 90 after stud
410 is inserted in opening 428. The 90 rotation of collar 432
en~ages the threaded portion of stucl 410 with the threaded por-
tion of opening 42~.
Figs. 34 and 37 show the means for rotating each
collar 432 to lock the corresponding stud 410 therein. Collar
432 is attached to a shaft 434 (Fig. 34) which is rotatably at-
tached to spindlehead 72 by bearings 436. A ball screw thread
438 is formed on shaft 434 and engages a ball nut 440. A hydraulic
piston anA cylinder mechanism 442 is coupled to ball nut 440 by
conventional means and pushes or pulls ball nut 440 axially a-
long ball screw thread 438 far enough to cause shaft 434 to ro-
tate by 9~, thereby rotating collar 432 by 90 to effect the
locking action described above. The ball screw turn-lock
mechanism described above has the advantage of being slender
enough in its lateral dimensions to fit in the limited space
available in spindlehead 72 outsi~e of spindle 82.
Fig. 39 shows a boring bar 444 which is adapted to be
handled~by the prevlously described automatic tool changer
3o and to be clamped in spindle 82. The shank 446 of boring bar
444 has the same dimensions as the shank 406 of multiple spindle
toolhead 405. Boring bar 444 has a flange 448 with a V-shaped
groove 450 therein. Groove 450 has the same dimensions as the
V-shaped groove 452 (Fig. 33) in multiple spindle toolhead 405.
The only dlfference in using boring bar 444, or some other single
tool, i~ place of multiple spindle toolhead 405 is that with a
single tool it is not necessary to turn collars 432, and since
coolant could get into openings 428 of collars 432 when they
are not used, a cir~ular shie~ 454 (Fig. 29) is rotatably
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atta^hed to spindlehead 72 to normally cover openLngs l~2~3 as
shown in Fig. 29.
When a single tool is used, shiel.d Ll54 covers open-
ings 428, but when a multiple spindle toolhead is used, shield
45~l is rotated by an angle ~ to pla^e opén~n~s 456 over openings
428 to expose them to receive sl;uds 410 as described previously.
Shield 45-~ is rotated by downward movement of a pin 458 on the
side of shield 454 a(ljacent to upright 300, which supports tool
change arm 29~. Each time tool change arm 298 is moved to its
forward position, described previously, an arm 460 which is
swingably mounted on upri~ht 300 mo~res to the posi.tion shown in
broken lines in Fig. 29 and engages pin l~58 in a slot 462 on a
bracket 464. Bracket 464 is couplecl to a hydraulic piston and
cylinder mechanism 466. When a multiple spindle toolholder is
about to be transferred into spindle 82, piston and cylinder
mechanism 466 is extended to drive bracket 464 and pin 458 to
the lower position shown in broken lines in Fig. 29. This
exposes openings 42~3. When a single tool is about to be
transferred into spindle 82, piston and cylinder mechanism
466 is not extended and openings 428 remain covered.
The mechanism for moving arm 460 between the two
positions shown in Fig. 29 is sho~ln in Fig. 28 and 30. Arm
460 is pivotally attached to upright 300 by a pivot pin 468.
Another arm 470 is rigidly attached crossways to arm 460 and
is pivotally attached to a slide 472 which is slidably mounted
in a housing ~74 (Fig. 28) on uprlght 300. Slide 472 is connected
by pin 476 (Fig. 28) to yoke 308 (Fig. 24) which moves tool change
arm 298 between its forward and rear positions. Every time
tool change 298 is moved forwardly, pin 476 pushes slide 472
forward which causes arm 460 to rotate about pin 468 as shown
in Fig. 28 and described previously.
An illustrative tool change cycle will now be de-
scribed step by step beginning with the ~ollowin~ initial con-
ditions:
(A) A boring bar 44 (Fig. 39) is clamped in
spindle 82 and is being used to machine a ~10rkpiece 86 (Fig.
2) on worktable 88.
(B) The empty tool socket 100 f`or boring bar 41~ is
at the tool transfer position in the upper deck of` tool storage
magazine 90 and locating stud 148 i5 lowered.
.
. .
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. lg ~
(C) The next tool to be used ls a multiple spindle
toolhead 405 (Fig. 33) which is in a socket 100 in the upper
deck of tool storage ma~azine 90 in a known position.
(D) Tilt unit 92 is emp~.y and is in the vertical
position.
(E) Tool change arm 174 is empty and is in the
central position opposite the lower deck of tool storage maga-
zine 90.
-(F) Tool change arm 298 is empty on both ends and
is in the vertical rear position.
Under the foregoing initial conditions, the tool
change cycle will proceed as follows:
(1) While the workpiece 86 is being machined7
motor 132 (Fig. 6) of the upper deck of tool storage magazine
90 is energized in the forward dire~tion to move tool sockets
100 past the tool transfer position shown at point 478 in Fig~
2.
(2) The number o~ times that a lug 140 (Fig. 7) pass-
es over proximity switch 142 is counted by a conventional
counter (not shown) until the known position of the tool socket
100 ^ontaining the desired toolhead 405 is at tool transfer
point 478. If, for example~ the empty tool socket 100 for
the tool in use is tool socket Number 15 and the toolhead 405
to be used next is in tool socket Number 19, the desired tool
will be at the tool transfer point ll78 on the fourth output
pulse of proximity switch 142.
(3) When the desired tool is at the tool trans~er
point 478, motor 132 (Fig. 6) is de-energized and coasts to
a stop. This places the desLred tool socket slightly past
tool transfer ooint 478.
(4) Hydraulic piston and cylinder mechanism 150
(Fig. 7) is extended to raise locatin~ stud 148 as shown in
Fig. 7,
(5) Motor 132 (Fig. 6) is energized for slow ro-
tation in the reverse direction to move lug 140 against locat-
ing stud 148 and locate the desired tool socket 100 at tool
transfer point 478. Motor 132 is allowed to stall ln the re-
verse direstion to hold lug 140 a~ainst locating stud 14~.
(6) Hydraulic piston and ^ylinder mechanism 258
(Figs. 16 and 17) is extended to raise tool change arm 174
. .
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. ~: , . : -.: , : .
- ~Z~1246
- ~o. --
to the level of the upper deck of tool storage magazine 90.
(7) Hydraulic piston and cylinder mechansim 202
(Flg. 10) is extended to move tool change arm 174 to tool
transfer point 478. This places tool cavity 220 (Fig. 10)
arouncl the V-groove oI the desired toolhead 405,
(S) Hydraulic piston anA cylinder mechanism 228
(Fig. 10) ~s retracted to move gripper jaw 224 into contact
with the V-gr~ove of toolhead 405 to clamp it to arm 174.
(9) Hydraulic piston and cylinder mechanism 256
(Figs. 16 and 17) is extended to lift toolhead 405 out of
tool socket 100.
(10) ~Iydraulic piston and cylinder mechanism
292 (Fig. 18) is extended to open collet clamp 286 in tilt
unit 92.
(11) Hydraulic piston and cylinder mechanism 202
(Fig. 10) is retracted to swing toolhead 405 over tilt socket
27LI.
(12) Hydraulic piston and cylinder mechanism 256
(Fig. 16) is retracted to lower toolhead 405 into tllt socket
274 of tilt unit 92.
(13) Hydraulic piston and cylinder mechanism 228
(Fig. 10) is extended to release gripper ~aw 224 from tool-
head 405.
(14) Hydraulic piston and cylinder mechanism 292
(Fig. 18) is retracted to close collet clamps 286 o~ tilt unit
92.
(15) Hydraulic piston and cylinder mechanism 194
(Fig. 10) is retracted to swing tool change arm 174 to its
forward position.
3 (16) Hydraulic piston and cylinder mechanisms 284
(Flgs. 18 and 19) are extended to swing tilt socket 274
and toolhead 405 to the horizontal position.
The foregoing steps 1 to 16, or any des~red portion
thereof, can be performed while workpiece 86 (Fig. 2) is being
machined with the tool placed in spindle 82 during the pre-
ceding tool change. Step 17J however, cannot be per~ormed until
the current machining operation on workpiece 86 is completed~
(17) The X, Y and Z axes drives f`or the machine tool
are actuated to bring spindle 82 into the tool change position
shown in Figs. 1 and 2 and spindle 82 is stopped.
. . . .
,. :. -`: . .- . ' ~
,~ . . . .
. : . . , .. , . :.
- : . :, . -,
~:
.
~ 24~
(1~) Hydraulic piston and cylinder mech~nism 318
(Fig. 21) is extended to rotate tool change arm 298 by 90
from the vertical to the horizontal positLon.
(1~) Hydraulic rotary actuator 376 (Fig. 21)
is rotated counterclockwise 90 to lock cam 360 (Figs. 25
and 2~) against tool ~rip Ijaws 350 and 352.
~ 20) Piston and cylinder mechanism 398 (Fig. 27
is eA~tended to open collet clamp 392 in spindle 82.
(21) Piston and cyllnder me^hanism 292 (Fig. 18)
is extended to open collet clamp 286 in tilt unit 92.
(22) Piston and cylinder mechanism 310 (Fig. 21)
is retracted to pull tool 441~ out of spindle 82 and toolhead
405 out of tilt socket 274.
(?3) Piston and cylinder mechanism 326 (Fig. 21) is
extended to rotate tool change arm 29~ by 130 to interchange
tool 444 and toolhead 40s.
(24) Piston and cylinder mechanism 466 (Fig. 29(
is extended to move openings 456 over lock openings 428.
(25) Piston and cylinder mechanlsm 310 (Fig. 21)
is extended to insert toolhead 405 into spindle 82 and tool
4!~4 into tilt socket 274.
(26) Piston and cylinder mechanisms 442 (Fig. 34)
are extended to rotate locking collars 432 by 90 to lock studs
410 therein.
(27) Hydr~ulic rotary actuator 376 (Fig. 21) is ro-
tated clockwise 90 to unlock cam 360 (Figs. 25 and 26) from
tool grip jaws 350 and 352.
(28) Hydraulic piston and cylin~ler mechanism 398
(Fig. 27) is retra_ted to close collet clamp 392 in spindle
30 82.
(2~) Hydraulic piston and cylinder mechanism 292
(Fig. 18) is retracted to close collet clamp 286 in tilt unit
92.
(30) PLston and cylinder mechanism 318 (Fig. 21)
is retracted to rotate tool change arm 298 from the horizontal
to the vertica:L position. After this step, machining of the
workpiece can begin again with the new tool.
(31) Piston and cylinder mechanlsms 284 (Fig. 18)
are retra^ted t3 tilt boring bar 41~4 and tilt socket 274 to the
vertical pO5 ition.
- . . . - :
. . ' ~'- ':
.: : :
46
- 22
(32) Piston and cylinder mechanism 1~l~ (Fig.
10) is extended to swing tool change arm 174 over tilt so^ket
274.
(33) Piston and cylinder mechanism 228 (Fig. 10) is re-
tracted to move gripper ~a~ 22l~ into contact with boring b~r
1~44,
(34) Hydraulic piston and cylinder mechanism 2g2
(Fig. 18) is extended to open collet clamp 2~6 in tilt unit
92.
(35) Piston and cylinder mechanisms 256 and 258 (Figs.
16 and 17) are both extended to raise boring bar 444 above the
level of the upper deck of tool storage magazine 90.
(36) Piston and cylinder mechanism 202 (Fig. 10)
is extended.to move borlng bar 444 to exchange position l~78.
(37) Piston and cylinder mechanism 256 (Fig. 16
and 17) is retracted to drop boring bar 444 into tool socket
100.
(38) Piston and cylinder mechanism 228 (Fig. 10)
is extended to move gripper jaw 22l~ out of contact with boring
bar 444.
(39) Piston and cylinder mechanism 202 (Fig. 10)
is retracted to move tool change arm 174 to its central po-
sition.
This completes the tool change cycle ~or the par-
ticular tools involved.
F~gure 40 is a block diagram of the electrical cir-
cuits which control the operation of the machine tool. Standard
coded instruction signals are punched on a punched tape 480
and include signals indicating which tools to use, when the
tools should be changed~ and detailed speed and positioning
instructions ~or spindle 82 to perform the desired machining
operations, along with any other ~unctions (such as coolant
flow) which are necessary for the operation of the machine tool.
The instruction signals are read off tape 480 by a tape reader
482 and are applied to a computer ~84 which controls the oper~-
tion ol the maohine tool through a conventional three axes drlve
system 486, a conventional spindle drive system 488 and other
conventional machine tool ^ircuits (not shown) which do not
interact with the automati^ tool changer o~ this invention.
The foregoing tool change sequence is controlled by
: ~ .
. . . : . .
:
. ~ , - , .
- 23 -
a suitable tool change computer routine 1~90 in computer 484
which controls the sequential ac-tuation of' tool chan~e sole-
noid valves 49~ to actuate the tool change piston and cylinder
mechanisms 491~ in the above descrlbed sequence. Although sole-
noid valves 492 are not shown individually~ it will be under-
stood by t~ose skilled in the art that one solenoid valve is
included in the circuit for each of the piston and cylinder
mechanisms des_ribed herein and illustrated in Figs. 1 to 39.
Each piston and cylinder me^hanism is either extende~l or rè-
tracted in accordance with the state of the corresponding sole-
noid valve. The state of all of the solenoid valves 492 at any
given time is controlled by tool change routine 490 in accordance
with well known prior art programming pra^tice to achieve the
sequence of-actuation described above in tool change steps 1 to
39.
Tool change limit switches 494 are coupled to tool
change components 1~96 in accordance with well known prior art
electrical control practice to indicate when the desired move-
ment of a tool change component has been completed. The electri-
cal control portions of the machine tool are entirely conventionalwith the exception of the actuation sequence described above in
tool change steps 1 to 39. Accordingly, the details of the
electrical control circuits are not described herein.
Although the illustrative embodiment of the invention
has been described in considerable detail for the purpose of
fully disclosing a practical operatlve structure incorporating
the invention, it si to be understood that the particular ap-
paratus shown and described is intended to be illustrative only
and that the various novel features of the invention may be in-
corporated in other structural forms with out departing from thespirit and scope of the invention as defined in the subjoined
clai~s.
- ; :: : . ~ , . - . ,: : : :,
