Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02228132 1998-01-28
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M~LTI-8PINDLE CNC LATHE
TEC ~ ICAL FIE~D
This invention relates generally to machine tools, and
more particularly to a multi-spindle CNC lathe that is
particularly adapted for use in conjunction with JIT and
SPC manufacturing philosophies.
_
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~O~rND AND 8 ~ M~12y OF T~IE 1NV~ L lON
Machine tools, including drills, lathes, milling
machines, grinders and other finishing machines, and more
complex devices such as screw machines, are all
characterized by a common objective: the manufacture of
large numbers of identical finished parts under conditions
of extreme accuracy and ~; economy. As such, interest
in and development of machine tools has paralleled the
advance of the industrial revolution.
Traditionally, machine tools were operated by
machinists who were among the most highly skilled and the
most highly paid of all workers. More recently, however,
machine tools have been adapted to a procedure known as
computer numeric control, or CNC, whereby the operation of
machine tools is regulated by computers or other
programmable controllers. In accordance with the CNC
technique, the dimensions, surface finishes, and other
characteristics of the part to be manufactured are supplied
in the form of sequential operating instructions which are
utilized by the CNC device to regulate the operation of the
machine tool. This allows the completion of finished parts
with more uniformity and more rapidity than has ever been
possible heretofore.
The adaptation of single spindle lathes, milling
machines, and similar devices to CNC techniques has largely
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been successful. However, in the case of multi-spindle
machine tools, previous attempts at automation have largely
comprised adapting the cams, gears, and other components
comprising such machines to servo control. Perhaps because
the approach has been one of adapting old designs to new
techniques, the effort to date at automating the operation
of multi-spindle lathes by means of CNC operation has
largely been unsuccessful.
The present invention comprises a multi-spindle lathe
which is entirely adapted for CNC operation. In accordance
with the broader aspects of the invention, a plurality of
spindles are positioned at spaced points about a central
axis. Each spindle has a collet which receives a length of
stock and rotates the stock about a spindle axis. An
indexing ?chAn;~ is provided for selectively positioning
the spindles at work stations located at e~ually spaced
points about the central axis.
Each work station comprises an internal tool slide
adapted to receive a cutting tool and to advance the
cutting tool toward and away from the rotating stock under
the action of a servo mech~ni~ . An external tool slide is
also provided for each work station and is adapted to
advance a cutting tool both toward and away from and
parallel to the axis of rotation of the stock. At each
work station the stock is turned rather than formed,
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meaning that the cutting tools of the individual work
stations maybe utilized to perform a variety of quite
distinct machi n i ng operations.
The multi-spindle CNC lathe of the present invention
is readily adapted for use in con~unction with both the
Just In Time (JIT) and the Statistical Process Control
(SPC) manufacturing philosophies. In accordance with JIT,
only the exact number of piece parts n~C~c~c~ry to complete
a particular assembly operation are ordered at any one
time. This eliminates the investment in inventory which is
necessary when large numbers of piece parts are ordered
simultaneously, and also eliminates the possibility that
previously ordered parts will become obsolete due to a
change in design. The machine tool of the present
invention is adapted to JIT because the economic batch is
smaller. This is because machine tools incorporating the
invention do not require the changing of the cutting tools
utilized at the various work stations in order to change
the nature of the piece parts being manufactured, and
because set up time is reduced dramatically.
In accordance with SPC, completed piece parts are
compared with a predetermined st~n~rd with a view towards
maintaining the dimensions of each part at the center of
the tolerance range. If the ~i~?n~ions of the parts being
manufactured begin to vary from the center of the tolerance
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range, due to cutting tool wear or otherwise, adjustments
in the manufacturing process are immediately instituted in
order to maintain tolerances. SPC is easily practiced in
the machine tool of the present invention since all of the
cutting tools are positioned by servo ?ch~ni~ which are
in turn under computer numeric control.
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BRIEF DESCRIPTION OF T~E DRAWING~
A more complete understanding of the invention may be
had by reference to the following Detailed Description,
when taken in conjunction with the acc -~-nying Drawings
wherein:
FIGURE 1 is a front view of a multi-spindle CNC lathe
incorporating the present invention;
FIGURE 2 is a front view of the base of the multi-
spindle CNC lathe of FIGURE 1 in which certain parts have
been broken away more clearly to illustrate certain
features of the invention;
FIGURE 3 is a top view of the base of FIGURE 2;
FIGURE 4 is a longitt~;nAl sectional view illustrating
the frame and certain operating components of the multi-
spindle CNC lathe of FIGURE l;
FIGURE 5 is an enlargement of a portion of FIGURE 4;
FIGURE 6 is a front view of the multi-spindle CNC
lathe of the present invention similar to FIGURE 1 in which
the covers of the apparatus have been removed;
FIGURE 7 is an illustration of certain components of
the multi-spindle CNC lathe of FIGURE 6 taken along the
lines 7-7 of FIGURE 6;
FIGURE 8 is an illustration of certain components of
the multi-spindle CNC lathe of FIGURE 6 taken along the
line 8-8 in FIGURE 6;
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FIGURE 9 is an enlargement of a portion of FIGURE 8;
FIGURE 10 is a further illustration of certain
components shown in EIGURE g;
FIGURE 11 is a side view of one of the internal slide
assemblies of the multi-spindle CNC lathe o~ FIGURE 6 in
which certain components have been broken-away more clearly
to illustrate certain features of the invention;
FIGURE 12 is an illustration of certain components of
the multi-spindle CNC lathe of FIGURE 6 taken along the
line 12-12 of FIGURE 6;
FIGURE 13 is an illustration of one of the external
slide assemblies o~ the multi-spindle CNC lathe of the
present invention;
FIGURE 14 is a sectional view taken along the line 14-
14 of FIGURE 13;
FIGURE 15 is a sectional view taken along the line 15-
15 of FIGURE 14 further illustrating the external slide
assemblies of the multi-spindle CNC lathe of the present
invention;
FIGURE 16 is longitudinal sectional view further
illustrating the external slide assemblies of the multi-
spindle CNC lathe of the present invention;
FIGURE 17 is a sectional view taken along the line 17-
17 o~ EIGURE 13;
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FIGURE 18 is an enlargement of a certain portion of
the apparatus illustrated in FIGURE 17;
FIGURE 19 is an illustration of certain of the
components of the multi-spindle CNC lathe of the present
5invention taken along the line 19-19 of FIGURE 6.
FIGURE 20 is an illustration of one of the spindles of
the multi-spindle CNC lathe of the present invention
showing the component parts thereof in a first orientation;
FIGURE 21 is view similar to FIGURE 20 showing the
10component parts of the spindle in a second o~ientation;
FIGURE 22 is an illustration similar to FIGURE 20
showing the component parts thereof in a third orientation;
FIGURE 23 is a sectional view illustrating the glut
.~. actuator of the multi-spindle CNC lathe of the present
15invention;
FIGURE 24 is as sectional view taken along the line
24-24 of FIGURE 25 and illustrating the spindle assembly
carrier of the multi-spindle CNC lathe of the present
invention;
20FIGURE 25 is an end view of the spindle assembly
carrier of the multi-spindle CNC lathe of the present
invention;
FIGURE 26 is an enlarged illustration of one of the
castings comprising the frame of the present invention;
25FIGURE 27 is illustration of the one of the stock
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carrying tubes of the multi-spindle CNC lathe of the
present invention;
FIGURE 28 is an enlarged sectional view of further
illustrating the stock carrying tubes of the multi-spindle
CNC lathe of the present invention;
FIGURE 29 is a ~ront view illustrating the stock
carriage assembly of the multi-spindle CNC lathe of the
present invention;
FIGURE 30 iS a partial sectional view illustrating the
in~ex;ng mechanism of the multi-spindle CNC lathe of the
present invention;
FIGURE 31 is a partial sectional view illustrating a
tool holder accessary useful in conjunction with the multi-
spindle CNC lathe of the present invention;
FIGURE 32 is a further illustration of the three point
mounting system of the frame of the multi-spindle CNC lathe
of the present invention; and
FIGURE 33 is a still further illustration of the three
point mounting system of the frame of the multi-spindle CNC
lathe of the present invention.
.4M~NDED S~ .
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DETATT~n DESCRIPTION
Referring now to the Drawings, and particularly to
FIGURE 1 thereof, there is shown a multi-spindle CNC lathe
50 incorporating the present invention. The lathe 50
includes a base 52 which also serves as an coolant
reservoir. A housing 54 extends upwardly from the base 52
and serves to enclose and protect both the mechanical
components and the production components of the multi-
spindle CNC lathe 50.
10A computer numeric control (CNC) system 56 is located
at one end of the housing 54. The CNC system 56 is
preferably of the type sold by General Electric Company as
and identified by that company as the Power Mate Motion
. ..
Control Systems, and may include a computer monitor screen
1558 and/or a plurality of status lights 60. A keyboard 62
may be used to effect computer control over the operation
of the lathe 50. The CNC system 56 may further include a
conventional control panel 64.
The housing 54 o~ the multi-spindle CNC lathe 50
further includes a sliding access door 66. The door 66 is
slidably supported on a slideways 68 and is provided with
a viewing window 70. The production components of the
multi-spindle CNC lathe 50 are located behind the door 66
when it is in the closed position as illustrated in FIGURE
- 25 1, and are observable through the viewing window 70 thereof.
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A hinged door 72 provides access to the mechanical
components of the lathe 50. Access ports 74 are normally
enclosed by removable covers 76. A cover 78 enclosing the
stock carriers o~ the lathe 50 extends le~twardly (FIG. 1)
from the main portion of the housing 54.
Referring now to FIGURES 2 and 3, the base 52 of the
multi-spindle CNC lathe 50 is shown in greater detail. The
base 52 is comprised entirely of steel plates which are
interconnected by welding. The base 52 is provided with a
plurality of mounting blocks 80 and a plurality of mounting
holes 82 which function to attach the operating components
of the lathe 50 to the base 52.
In addition to supporting and locating the operating
components of the lathe 50, the base 52 serves as an
lS coolant reservoir. Coolant entering the base 52 is
initially contained by a plate 84 which defines a coolant
level 86. Chips caused by operation of the multi-spindle
CNC lathe 50 enter the base 52 through a port 88 and are
received on a chip conveyor so located above the plate 84.
The conveyor 90 transports the chips out of the base 52,
where upon the chips fall into a chip receiving container
92 under the action of gravity.
During operation of the lathe 50, coolant constantly
flows over a lip 94 located at one end of the plate 84.
From the lip 94 the coolant flows into and through a basket
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96 which functions to strain the coolant, thereby removing
any debris which is not transported out of the base 52 by
the chip conveyor 90. Preferably, two baskets 96 are
employed in the operation of the lathe, one located in the
working position as defined by a bracket 98 and the other
positioned on a drain platform 100 which allows coolant to
drain out of the basket 96 prior to the removal of de~ris
therefrom. Coolant flowing through the basket 96 located
in the working position as defined by the bracket 98 flows
lo along a path defined ~y the arrows 102 and is returned to
the operating components of the lathe 50 by a pump (not
shown) which withdraws the coolant from the base at
aperture 103. This flow path maintains uniform temperature
of the base 52 and eliminates static spots which can cause
the coolant to become rancid.
As is best shown in FIGURE 4, the multi-spindle CNC
lathe 50 includes a frame 104 comprising an important
feature of the invention. The frame 104 include precision
castings 106 and 108 which function to support and align
the operating components of the lathe S0. The casting 106
comprises opposed walls 110 and 112, and the casting 108
comprises opposed walls 114 and 116.
The walls 110 and 112 of the casting 106 define
opposed surfaces 120 and 122, respectively. The surfaces
120 and 122 are ground flat and smooth utilizing Blanchard
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- IPEA/US 1 4MAR t997
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grinding or a functionally equivalent process. The walls
114 and 116 comprising the casting 108 defined opposed
surfaces 124 and 126 which are identically processed, and
are therefore equally flat, smooth, and parallel. The
surfaces 122 and 124 define the alignment surfaces of the
frame 104 of the lathe 50.
The frame 104 further comprises four tie rods 128
which are match machined in order to maintain precise
parallelism between the surface 1'22 of the casting 106 and
the surface 124 of the casting 108. Each tie rod 128
includes an elongate central portion 130 extending to
reduced diameter portion 132 which in turn extends to a
threaded end member 134. At the bottom of the casting 108,
a bushing 13 6 is mounted on each reduced diameter portion
132 and is received in aligned apertures 138 and 140 ~ormed
in the casting 108 and formed in a mounting block 142.
A plurality of nuts 144 are each threadedly engaged
with a threaded end portion 134 of one of the tie rods 128.
The nuts 144 engage washers 146 which in turn engage
compression members 148. Thus, upon precise tightening of
the nuts 146, using, for example, a torque wrench, the
castings 106 and 108 comprising the frame 104 are securely
positioned with respect to one another.
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-14-
At the upper ends of the castings 106 and 108, the
reduced end portions of the rods 128 extend through
apertures 138' formed in the castings 106 and 108.
__
Likewise, the nuts 144 engage the washers 146 which
directly engage the castings 106 and 108.
The mounting blocks 1*2 and 142'aré secured to the
base 52 by plurality of threaded fa~teners 152. The
mounting blocks 142 engage the mounting blocks 80 of the
base 52 to precisely position the frame 104 with respect
thereto. An important aspect of the present invention
comprises the use of the three point mounting system
comprising the two mounting blocks 142 and 142' to mount
the frame 104 on the base 52. By this means any
possibility of tipping, wobbling, or misalinement between
the base 52 and the frame 104 is eliminated.
The three point mounting system which supports the
frame 104 on the base 52 is further illustrated in FIGURES
32 and 33. Each mounting block 142 engages an individual
mounting block 80 of the base 52 to support the casting 108
at two parts. In contrast, the mounting block 142' bridges
between two mounting blocks 80 and supports the casting 106
at a single, central point, thereby providing three point
AME~IDED S,~E~T
. ~
:
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--15--
support for the frame 104. Referring again to FIGURE 4, a
pin 150 extends through aligned apertures 139 in the
casting 106, and an aperture 140~ formed in the center of
the mounting block 142'. A nut 144 is threadably engaged
within the end portion 134 of the pin 150, and engages a
washer 146 which engages a compression member 148.
A spindle drive motor 154 is mounted at one end of the
frame 104 of the multi-spindle CNC lathe 50. The spindle
drive motor is preferably a variable speed alternating
current electric motor. The motior 154 is supported by a
motor mounting adaptor 156 which is in turn supported by a
bearing housing 158. The bearing housing 158 is secured to
the wall 110 of the casting 106 of the frame 104 by a
plurality of threaded fasteners 160.
The motor 154 has an output shaft 162 which extends to
a flexible coupling 164. The flexible coupling 164 in turn
drives a spindle drive shaft 166. The drive shaft 166 is
rotatably supported by a bearing 168 which is retained in
the bearing housing 158 by an end plate 170 that is in turn
secured by threaded fasteners 172. A spacer 174 and a lock
nut 176 complete the drive shaft/bearing assembly.
Referring to FIGURES 4 and 5, the drive shaft 166
extends through a piston 180 which is secured to a tubular
ram 182 by a plurality of threaded fasteners 183. The
piston 180 is mounted in a cylinder 184 which is located
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relative to the wall 112 of the casting 106 by a hardened
precision dowel pin 186 and is secured to the wall 112 by
a plurality of threaded fasteners 188. A first hydraulic
fluid chamber l90 is defined at one end of the piston 180
5and is isolated by a plurality of seals 192. The chamber
190 is closed by an end plate 194 which is secured to the
cylinder 184 by a plurality of threaded fasteners 196. The
end plate 194 is provided with a hydraulic fluid inlet and
outlet port 198.
10A second hydraulic fluid chamber 200 is located at the
opposite end of the piston 180 and is isolated by a
plurality of seals 202. The chamber 200 is provided with
a hydraulic fluid inlet and outlet port 204 formed in the
cylinder 184. Thus, upon selective application of
15hydraulic pressure to one of the chambers 190 or 200 and
the simultaneous release of hydraulic pressure from the
opposite chamber, the piston 180 and the tubular ram 182
are caused to move longitll~in~lly relative to the cylinder
184.
20The end of the tubular ram 182 remote from the piston
180 is provided with a flange 206. A retaining ring 208
engages the flange 206, and a plurality of threaded
fasteners 210 secure the retaining ring to an adapter 212.
The adapter 212 supports a bearing 216 which rotatably
supports the shaft 166. The threaded fasteners 210 and
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-17-
the retaining ring 208 also function to secure the tubular
ram 182 to a spindle carrier assembly 218.
The working components of the multi-spindle CNC lathe
50 are illustrated in FIGURES 6 through 19, inclusive. A8
is clearly shown, for example, in FIGURES 7, 8, and 9, the
particular multi-spindle CNC lathe 50, as illustrated in
the Drawings and described herein comprises an eight
spindle device. However, as will be appreciated by those
skilled in the art, the present invention is readily
adapted ~or use in conjunction. with multi-spindle CNC
lathes having any desired number of spindles as may be
dictated by the requirements of a particular application of
the invention. Internal slide assemblies 220
comprising the multi-spindle CNC lathe 50 are illustrated
in FIGURES 7, 8, 9, 10, and 11, inclusive. Referring
particularly to FIGURES 7 and 11, each internal slide
assembly 220 comprises a servo mechanism which includes a
motor 224 which is secured to a motor mounting plate 226 by
a plurality of threaded fasteners 228. The motor mounting
plate 226 is in turn secured to a mounting plate 230 by a
plurality of threaded fasteners 232. The mounting plate
230 is in turn secured to the wall 110 of the casting 106
comprising the frame 104 by a plurality of threaded
fasteners 234.
The motor 224 has an output shaft 236 which is secured
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-17A-
to a drive pulley 238. A drive belt 240 extendq around the
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drive pulley 238 and a driven pulley 242. The driven
pulley 242 is mounted on a spacer 244 which is in turn
secured to an adapter 246. Thus, upon operation of the
motor 224, the adapter 246 is rotated under the action of
the motor 224, the output shaft 236, the drive pulley 238,
the belt 240, the driven pulley 242, and the spacer 244.
The adapter 246 is rotatably supported on the plate
llO by bearings 248. The bearings 248 are supported in a
bearing housing 250 by a plurally of threaded fasteners 252
which extend through the mounting plate 230. A ball nut
254 is mounted on the adapter 246 and is secured thereto by
a plurality of threaded fasteners 256.
A ball screw 258 extends through and is operatively
engaged with the ball nut 254. The ball screw 258 is
secured against rotation relative to the ball nut 254.
Thus, upon actuation of the motor 224 to rotate the adapter
246 and the ball nut 254, the ball screw 258 is selective
extended or retracted.
A target adapter 260 extends from one end of the ball
screw 258 and supports a target 262. A sensor bracket 264
is secured to the mounting plate 226 by a plurality of
threaded fasteners 266. Proximity sensors 268, 270, and
272 are mounted on the bracket 264. Upon the alignment of
the target 262 therewith, the proximity sensors 268, 270,
and 272 are actuated to generate a signal indicative of the
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--19--
positioning of the ball screw 258 relatively to the frame
104 of the lathe 50. Proximity sensor 270 is indicative of
the normal positioning of the ball screw 258, proximity
sensor 272 is indicative of the fully retracted positioning
of the ball screw 258, and proximity sensor 268 is
-
indicative of the fully extended position of the ball screw
258.
The motor 224 operates under control of the CNC system
54 to position the ball screw 258. The outputs of the
proximity sensors 268, 270, and 272 are directed to the CNC
system 54, which in turn operates the motor 224 to properly
position the ball screw 258 in accordance with the program
being run.
The ball screw 258 extends through a ball screw boot
. ,_,
274. The boot 274 is secured to the wall 112 of the
casting 106 of the frame 104 by a plurality of threaded
fasteners 276. At the distal end of the boot 274 there is
provided a rod wiper 278.
The end of the ball screw 258 remote from the target
adapter 260 is provided with a threaded portion 280. A
pusher bracket 282 is secured to the end of the ball screw
258 by a nylon insert lock nut 284 threadably engaged with
the end 280 of the ball screw 258. A flat washer 286 is
located between the pusher bracket 282 and the ball screw
258.
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A slide body 292 is secured to the pusher bracket 282
for reciprocation under the action of the ball screw 258
and the ball nut 254 which i~ in turn actuated by the motor
224 under the control of the CNC system 54. Drive keys 294
are mounted at one end of the slide body 292 and is secured
thereto by a plurality of threaded fasteners 296. The
slide body 292 is provided with a conventional central bore
298 and is adapted to receive a conventional tool holder,
which in turn receives a conventional tool such as a drill,
lo reamer, etc.
Those skilled in the art will appreciate the fact that
tool slides of the type shown on FIGURES 7, 8, 9, 10 and
11, inclusive, and described hereinabove in conjunction
therewith are referred to in the machine tool industry as
ram slides.
Those skilled in the art will further appreciate the
fact that the slide body 292 and tool holder received
therein comprise static devices which are adapted to
provide end working functions on rotating stock. The
internal tool slide assembly 220 is also adapted for use
with active slide components adapted for performing end
working functions such as tapping, profile work, etc. and
also for performing the pick up function after the work
piece has been severed.
FIGURE 31 illustrates a tool holder assembly 700 which
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~PEAIIJS 1 4 MAR l
may be used in lieu of the passive tool holder assembly of
FIGURE 11 in the internal slide assembly of the multi-
spindle CNC lathe 50 of the present invention, if desired.
The tool collet holder assembly 700 includes a tool holder
receiver 702 which is rotatably supported on a sub-frame
704 by bearings 706. A motor 708 has as output 710 which
drives a drive pulley 712. A belt 714 extends around the
drive pulley 712 and a driven pulley 716 which is
operatively connected to the tool holder receiver 702. In
the use of the apparatus 700, a cohventional tool holder is
positioned in the bore 720 of the tool holder receiver 702.
The tool holder in turn receives a conventional tool. By
means of the motor 708, the tool is adapted for rotation as
it is advanced toward and away from the rotating stock. By
this means the tool may be utilized to provide, for example
tapping of the stock.
Referring to FIGURE 9, each slide body 292 has a pair
of guide blocks 304 secured thereto by threaded fasteners
306. The guide 304 blocks are received in correspondingly
shaped, hardened and precision ground, guideways formed in
a guide body 308 and defined by components 307 and 314.
Sliding movement of the guide blocks 304, and therefore the
slide bodies 292, is facilitated by the positioning of
layers of polytetrafluroethylene 310 between the guide
blocks 304 and the corresponding guideways.
A~EN~ED SHEEr
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IPE~IUS 1 4MAR 199
The construction of the guide body 308 will be best
understood by simultaneous reference to FIGURES 5 and 9.
The component parts 307 of the guide body 308 comprising
the guideways are secured to the cylinder 184 by a
plurality of threaded fasteners 312. The component parts
. 314 are secured by a plurality of threaded fasteners 316.
A cover plate 318 is mounted at the end of the guide body
308 remote from the piston 180 and is secured by plurality
of threaded ~asteners 320.
Coolant is discharged from flexible nozzle assemblies
322 to the working area. The nozzle assemblies 322 are
selectively mounted in discharged apertures 324 provided in
the end plate 318. The apertures 324 extend to a
. ~ passageway 326. Coolant is directed into the passageway
326 for discharge from the flexible nozzle assemblies 322
through an inlet port 328 formed in the cylinder 184
Referring now to FIGURES 12 through 19, inclusive, the
multi-spindle CNC lathe 50 includes a plurality of external
slide assemblies 330. Each external slide assembly 330 is
supported on the wall 114 of the casting 108 of the frame
104 by a support bracket 332 which is secured to the wall
114 by a plurality of threaded fasteners 334. Each
external slide assembly 330 is adapted to support and
position a cutting tool 336 relative to rotating stock.
The external slide assemblies 330 function to move cutting
A~END~ SHEEF
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p~-JJS 96~13173
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tools 336 both toward and away from the rotating stock and
toward and away from the wall 114 of the frame 104, i.e.,
parallel to the stock.
Referring to FIGURES 13 and 15, each external slide,
referred to in the industry as a saddle, assembly 330
. includes a housing 340 which is guided by a circular guide
342 and a rectangular guide 344. The guide 342 is mounted
on the housing 340 and is slidably supported by bushings
343 mounted on the bracket 332. The guide 344 is mounted
on the bracket 332.
Referring to FIGURE 15, a servo mechanism which
includes a motor 346 mounted on a motor mounting plate 350
and is secured thereto by a plurality of threaded fasteners
,~- (not shown). The motor mounting plate 350 is in turn
supported on a mounting plate 352 by a plurality of
threaded fasteners 354. Mounting plate 352 is mounted on
wall 116.
The motor 346 has an output shaft 356 which is
connected to a drive pulley 358. The drive pulley 358
drives a belt 360 which in turn drives a driven pulley 362.
The driven pulley 362 is secured on a adapter 364 by an
spacer 366. The adapter 364 is rotatably supported on the
plate 116 by a bearing 368 which is mounted in a bearing
housing 370. The bearing housing 370 is secured in the
plate 352 by a plurality of threaded ~asteners 372.
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A ball nut 374 is secured to the adapter 364 by a
plurality of threaded fasteners 376. Thus, upon actuation
of the motor 346 operating through the drive shaft 356, the
drive pulley 358, the drive belt 360, and drive pulley 362,
the adapter 366, and the spacer 364, the ball nut 374 is
actuated to rotate relative to the plate 116. A ball screw
378 extends through and is operatively connected to the
ball nut 374.
A target adapter 380 is secured to one end of the ball
screw 378 and has a target 382 mounted on th~e distal end
thereof. A plurality of proximity sensors 384, 386, and
388, are mounted on a support plate 390 which is secured to
the motor mounting plate 350 by a plurality of threaded
fasteners 392. When the target 382 is aligned with one of
_.
the proximity sensors 384, 386, or 388, a signal is
generated indicative of the positioning of the housing 340
of the external slide assembly relative to the plate 114 of
the frame 104.
The end of the ball screw 378 remote from the target
adapter 380 comprises a threaded end portion 394. The ball
screw 378 iS secured to the housing 340 of the external
slide assembly 330 by a nylon insert lock nut 396.
Therefore, upon operation of the motor 346, the ball nut
374 ~unctions to actuate the ball screw 378 to locate the
housing 340 relative to the wall 114. Referring to FIGURE
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16, the housing 340 is supported for sliding movement
toward and away from the wall 114 by guide members 342 and
344.
Referring to FIGURES 1 and 15, the motor 346 operates
under control of the CNC system 56 to position the ball
screw 378. The outputs of the proximity sensors 384, 386,
and 388 are directed to the CNC system 56 which in turn
operates the motor 346 to position the ball screw 378 in
accordance with the program being run.
As is best shown in FIGURES 16 and 17, each external
slide assembly further comprises a servo mechanism
including a motor 400 mounted at the end of the housing 340
remote from the cutting tool 336. The motor 400 has an
output shaft 402 which is connected to a flexible coupling
404 which is in turn connected to one end of a ball screw
406. The ball screw 406 is rotatably supported by bearings
408 and 410 mounted in the housing 340.
A ball nut 412 is mounted on and operatively connected
to the ball screw 406. The ball nut 412 is secured to a
tool slide 414 by a plurality of threaded fasteners 416.
The tool slide is slidably supported in the housing or
saddle 340. Thus, upon actuation o~ the motor 400 to
rotate the ball screw 406, the ball nut 412 functions to
move the slide 414 and therefore the cutting tool 336
inwardly and outwardly relative to the housing 340.
~VI~ND~D SHEET
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!PEAIUS ~ 4 MAR 1997
-26-
Those skilled in the art will appreciate the fact that
tool slides of the type illustrated in FIGURES 15, 16 and
17 and described hereinabo~e in conjunction therewith are
referred to in the machine tool industry as ram slides.
The motor 400 operates under control of the CNC system
56. The motor 400 and the slide 414 have associated
therewith a target and a plurality of proximity sensors
like the target 382 and the sensors 384, 386, and 388
associated with the ball screw 378. The CNC system 56
receives signals ~rom the sensors-to allow control over the
positioning of the cutting tool 336.
Referring particularly to FIGURE 18, there is shown a
quick disconnect coupling for the cutting tool 336. The
cutting tool 336 is supported on a mounting bar 416
positioned within the slide 414. The cutting forces
resulting from engagement of the cutting tool 336 with
rotating stock are taken by a reaction block 418 which is
secured to the slide 414 by a threaded fastener 419. The
mounting bar 416 and therefore the cutting tool 336 are
normally secured in the position shown in FIGURE 18 by a
retaining bar 420 having a ramp portion 422. A pin 424 is
positioned between the ramp portion 422 and the mounting
bar 416 and functions to retain the mounting bar 416 and
therefore the cutting tool 336 in place. A spring 426
normally retains the bar 420 in place.
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PEAlUS 1 4MAR 1991
--27 -
A stop 428 is mounted in the housing 340 at the remote
end of the slide 414. When the slide 414 is ~ully
retracted under the action of the ball nut 412 and the ball
screw 406, the retaining bar 402 engages the stop 428.
This action compresses the spring 426 thereby relieving the
pressure imposed on the pin 424 by the ramp portion 422.
This in turn allows the cutting tool 336 and the mounting
bar 416 to be disengaged from the slide 414.
The multi-spindle CNC lathe 50 of the present
invention further includes a plurality of spindles 430 of
the type illustrated in FIGURES 20, 21, and 22. Each
spindle 430 is rotatably supported in the spindle carrier
218 of FIGURE 4 by bearings 432 and 434 and is retained
. .
therein by threaded fasteners 436 and 438.
Each spindle 430 comprises a main body portion 440
having a planet gear 442 mounted thereon. Spacers 444 and
446 are interposed between the planet gear 442 and bearing~
432 and 434 respectively. A collet receiving bore 448
extends through the main body 440 and a conventional self-
opening collet 450 is disposed therein. A conventional
collet aligning mechanism 452 maybe positioned at the
collet receiving end of the bore 448. A driving key 454
assures proper alignment between the collet and the
spindle.
The spindles 430 of the present invention comprise a
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unique collet opening, collet closing, and collet releasing
mechanism. A glut 456 is slidably supported on a glut
guide 458 and includes a dog 460 which engages a slot 462
formed in a collet actuator 464 mounted on the spindle 430.
The collet actuator 464 includes a retainer 466 which is
secured by threaded fasteners 468. A spring actuator 470
is slidably supported within the main body 440 of the
spindle 430. A spring actuated retainer 472 is slidably
supported on the spring actuator 470.
The collet locked position ~s illustrated in FIGURE
20. At this point the glut 456 has been actuated to
position the collet actuator 464 at its extreme rearward
position relative to the collet 450. A series of wedges
474 have been forced downwardly. This action moves a
_,.
slider 476 rearwardly compressing compensating washers 478,
whereby a length a stock to be worked (not shown) is
securely retained in the collet 450. A dog 480 on the
slider 472 is disengaged from the spring retainer 466
whereby a plunger 482 is fully extended under the action of
a spring 484.
In FIGURE 21 the glut 456 is actuated to move the
spring actuator 464 toward the planet gear 442. The wedges
474 move upwardly under the action of the compensating
washers 478 and centrifugal force. The retainer 466
approaches but does not quite engage the dog 480, whereby
AMENDED SH~ET
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~PE~IUS 1 4MAR 1997
-29--
the pin 482 r~m~-n.q in position. At this point the self-
opening collet 450 is released sufficiently to permit the
repositioning of stock extending therethrough and/or to
receive a new length o~ stock having the same dimensions as
the previously engaged stock.
In FIGURE 22 the glut 456 is actuated to move the
spring actuator 464 to its extreme position. At this point
the spring 484 is substantially compressed due to actuation
of the pin 482 by the spring actuator 470 and the
engagement of the dog 480 with 'the retaine~ 466. This
aligns a detent 486 with a retaining ball 488 to allow the
ball 488 to move upwardly, thereby permitting the removal
of the collet 450. Collet removal is indicated when
a different size or type of stock is to be retained by the
collet 450 for rotation by the spindle 430. Removal of the
collet 450 may be effected either manually or automatically
through the use of conventional collet removal and
replacement apparatus.
FIGURE 23 illustrates a glut actuator assembly 490
useful in the practice of the present invention to operate
the glut 460 shown in FIGURE 20. The glut actuator
assembly 490 is mounted on the wall 116 of the casting 108
and is supported thereon by a mounting plate 492 which is
secured to the wall 116 by a plurality of threaded
fasteners 494. A glut actuator 496 is secured to a movable
AMENDED SY.E-tT
CA 02228132 1998-01-28
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-30-
housing 498 which is slidably supported on a guide rod 500.
The guide rod 500 is secured to the mounting plate 492 by
a threaded fastener 502. A piston 504 is fixedly mounted
on the guide rod 500, and is provided with seals 506. An
inner piston 508 is slidably supported on the guide rod 500
.
and is provided with seals 510. An outer piston 512 is
likewise slidably supported on the guide rod 500 and is
provided with seals 514.
The pistons 504, 508, and 512 divide the housing 498
into four chambers 516, 518, 520,-and 522. Hydraulic fluid
inlet and outlet ports 526, 528, 530, and 532 extend to the
chambers 516, 518, 520 and 530, respectively. Chamber 516
is secured against leakage by seals 534, and chamber 522 i8
secured against leakage by seals 536.
It will thus be understood by those skilled in the art
that by selectively admitting pressurized hydraulic fluid
to one of the chambers 516, 518, 520, and 522, and by
simultaneously draining hydraulic fluid from the remaining
chambers, the housing 498 and therefore the glut actuator
496 maybe selectively located in any of four positions
relative to the guide rod 500 and the wall 116. In this
manner the glut actuator assembly 490 of FIGURE 23
functions to position the glut 460 o~ FIGURE 20, thereby
selectively engaging, disengaging, or releasing the collets
450 of the multi-spindle CNC lathe 50 of the present
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invention. The fourth position of the glut actuator
assembly 490 is used to allow indexing of the spindle
carrier 218.
Referring to FIGURE l9, the multi-spindle CNC lathe 50
i8 shown as having eight gluts 456, eight glut guides 458,
eight dogs 460, and eight glut actuator assemblies 490.
This is to demonstrate the use of such components at any of
the work stations and in as many numbers as needed for the
particular application of the invention. Usually, no more
than two gluts and glut actuator assemblies will be needed.
The spindle carrier 218 of FIGURE 4 is further
illustrated in the FIGURE 24. Multi-toothed coupling
portion 540 having teeth 542 formed at equally spaced
_~' intervals therearound is secured between opposed body
lS portions 544 and 546. Coupling portion 540 is aligned by
~MENaED SHEE~
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means of a dowel 548 and is secured in place by means of
threaded fasteners 550. The body portions 544 and 546 are
in turn secured together by threaded fasteners 552.
The spindle supporting bearings 434 illustrated in
FIGURES 20, 21, and 22 are received in a bearing receiving
cavity 554 formed in body member 546. The bearings 434 are
secured in place by a plate 556 which is retained by the
threaded fasteners 438. The bearings 432 as illustrated in
FIGURES 20, 21, and 22 are received in a bearing receiving
cavity 558 formed in the body member 544. The bearings 432
are secured by a plate 560 which is secured in place by the
threaded fasteners 436.
Referring again to FIGURE 24, the body portions 544
and 546 are preferably secured in~ place prior to the
machining of the bearing receiving cavities 554 and 556,
thereby assuring precise alignment between the cavities.
It will be appreciated that it is occasionally necessary to
disassemble the body portions 544 and 546. To this end
there is provided an alignment ring 562 having extended
profile portions 564. The profile portions comprise
segments of approximately 60 degrees which are in turn
separated by vacant segments of approximately 60 degrees.
By means of the profile portions 564 of the alignment ring
562, the body portions 544 and 546 of the spindle carrier
218 may be separated and reassembled without loss of
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alignment between the bearing receiving cavities 554 and
558.
Referring to FIGURES 4, 20-22 and 24, the sun gear 570
is rotatably supported within the spindle carrier 218. The
sun gear 570 is rotatably supported by bearings 572 which
~- are retained by a plate 574. The plate 574 is in turn
retained by threaded fasteners 576.
The sun gear 570 has an internal spline 578 which
engages in the internal spline 579 of the drive shaft 166
FIGURE 4. In this manner the sun gear is rotated under the
action o~ the spindle drive motor 154. The sùn gear 570
engages the planet gears 442 of the spindles 430, whereby
the motor 154 functions to rotate the spindles at a
predetermined speed.
~~ 15 The spindle carrier 218 is secured to the tubular ram
182 by means of the threaded fasteners 210 which engage
complementary threaded apertures 580 formed in the body
portion 546. Thus, upon actuation of the piston 180, the
positioning of the spindle carrier 218 is shifted
longitudinally relative to the frame 104.
Referring to FIGURES 4, 25 and 26, the casting 108
comprising the frame 104 has a multi-toothed coupling
portion 582 secured therein by threaded fasteners 586. The
coupling portion 582 comprises a plurality of teeth 588
which are inverse to the teeth 542 of the coupling portion
A~ENOED SHEEr
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- ~GTIUS 96/13173
IP~A/US I 4MAR 199
540 of the spindle carrier 218. Thus, when the piston 180
is actuated to move the ram 182 toward the casting 108, the
teeth 542 oi~ the spindle carrier 218 engaged the teeth 588
of the coupling portion 582 on the casting 108 to secure
the spindle carrier 218 against rotation relative to the
frame 104 of the multi-spindle CNC lathe 50. Conversely,
when the piston 180 iS actuated to move the ram 182 away
from the casting 108 the teeth 542 on thë spindle carrier
218 are disengaged from the teeth 588 of the coupling
portion 582 on the casting 108', whereupon .the spindle
carrier 218 iS adapted ~or i n~ C; ng relative to the frame
104 of the lathe 50.
The frame 104 iS provided with a bearing member 590.
The bearing member 590 has a precisely machined internal
surface 592 which rotatably supports the spindle carrier
218 for indexing. To this end the lower segment of the
surface 592 iS provided with a layer of
polytetrafluroethylene 594 to facilitate rotation of the
spindle carrier 218 relative to the bearing ring 590
The multi-spindle CNC lathe 50 iS provided with a
plurality of stock carrier assemblies 600 which are best
illustrated in FIGURES 27 and 28. Each stock carrier
assembly 600 includes an inner stock carrying tube 602
which extends through one of the spindles 430 and is
supported therein for rotation with the collet 450 received
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-34-
in and rotated by the spindle 430. Each tube 602 is
secured to a nut 604 which is threadedly engaged with the
spindle 430, thereby securing the tube 602 for rotation
with the collet 450. The use of a stock carrying tube
adapted for rotation with the stock received therein
comprises an important feature of the present invention and
is a signicant departure from the prior art.
Throughout a significant portion of its length the
tube 602 extends through a stationary tube 606. The tube
606 is provided with a conventional closure 60.8 located at
the end thereof remote from the spindle 430. The
particular closure 608 illustrated FIGURE 27 is of the
bayonet variety and is provided with a handle 610 which is
moved inwardly to release the closure 608 for the insertion
of stock into and through the tubes 606 and 602. At all
other times the closure 608 remains positioned as shown in
FIGURE 27 to seal the interior of the tube 606 against
leakage of coolant therefrom.
The rotating tube 602 has a plurality of apertures 612
formed therein to permit the flow of coolant out the tube
602 into the tube 606. The tube 606 extends to a seal 614
which prevents leakage of coolant from the end of the tube
606 remote from the closure 608. A secondary seal 616 is
mounted on the seal 614 and extends along the tube 602
further to prevent leakage of coolant.
~MENDED SHEET
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IPEAI~ 1 4MA~
Each tube 606 is further provided with fixtures 618
and 620 which function to admit coolant into the tube 606.
Whenever it is desired to advance the position of the stock
located within and rotating with the tube 602, the pressure
of the coolant within the tube 606 is increased. It will
- be understood that one end of the stock is situated within
the assembly comprising the tubes 602 and 606, and is
therefore subject to the application o~ an endwise force
resulting from the increa~e in coolant pressure. However,
the opposite end of the stock is situated withln the collet
and is therefore not subject to the increased pressure of
the coolant within the tubes 602 and 606. By this means
there is provided an endwise ~orce on the stock which
pushes the stock through the collet 450 without requiring
the use independent stock advancing mechanisms. The
presence of the coolant within the tubes 602 and 606 also
provides significant vibration damping and noise reduction
as compared with prior art stock advancing mechanisms.
The stock carriage mechanism of the multi-spindle CNC
lathe 50 is illustrated in FIGURE 29. The inner stock
carrying tube 602 and the stationary tube 606 of the stock
carrier assembly 600 are supported on a carriage assembly
622. Rings 624 are provided at each end of a stock
carriage housing 626. Rollers 628 are provided on the
carriage assembly 622 and engage the rings 624. By this
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IPEAIUS 1 4MAR 199~
means the carriage assembly 622 and therefore the stock
carrier assembly 600 is adapted for revolution about the
central axis 632 of the multi-spindle CNC lathe 50.
An indexing mechanism 640 for the multi-spindle CNC
lathe 50 is illustrated in FIGURES 29 and 30. A motor 642
drives an indexer 643 which has an output 644 that drives
a drive pulley 646. A belt 648 extends around the drive
pulley 646 and functions to actuate a driven pulley 650
under the action of the motor 642 and the indexer 643. The
driven pulley 650 is connected to.a rotator plate 652 which
is connected to the carriage assembly 622 by a piurality of
threaded fasteners 658. Thus, upon actuation of the motor
642 and indexer 643, the carriage assembly 622 and the
stock carriage tubes mounted thereon are revolved around
~' 15 the axis 632.
A spider 656 is mounted to the assembly 622 for
rotation therewith under the action of the motor 642 and
the indexer 643. The spider 656 comprises a plurality of
pins 660 each having opposed spherical ends 662. The
spherical ends 662 of the pins 660 are received in bores
664, thereby accommodating a predetermined amount of
misalignment between the assembly 622 and a connector 666
which is secured to the spindle carrier 218 by means of a
plurality of threaded fasteners 668. Thus, upon actuation
the motor 642 functions not only to rotate the assembly 622
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but also to rotate the spindle carrier assembly 218
simultaneously therewith.
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PCTll~S 96 ~13 17~
IPEAIUS 1 4MAR 1~97
-38-
OPERATION
In the operation of the multi-spindle CNC lathe 50,
one or more of the closures 608 is disengaged to permit the
insertion of stock into the tube 606 and the tube 602 of
the stock carrier assembly. The glut actuator assembly 490
is then actuated to operate the glut 456 to open one or
more of the collets 450. Stock is initially positioned
~,
manually. Thereafter, pressure of the coolant within the
tubes 602 and 606 of the stock carrier assembly is
selectively increased, whereupo~ the stock is advanced
through the corresponding collet 450 until it properly
positioned.
Indexing of the stock relative to the tools of the
multi-spindle CNC lathe 50 begins with actuation of the
piston 180 to move the ram 182 righwardly (FIGURES 4 and 5)
thereby disengaging the teeth 542 of the multi-tooth
coupling portion 540 of the spindle carrier 218 (FIG 24)
from the teeth 588 of the coupling portion 5820 which is
secured to the frame 104 (FIG 26). The indexing motor 642
(FIG 30) is then actuated to index the carriage assembly
622 and therefore the tubes 602 and 606, and also the
spindle carrier 218 having the spindles 430 and the collets
450 mounted thereon. This action causes the stock, the
tubes 602 and 606, the spindles 430, and the collets 450 to
revolve about the axis 632 of the multi-spindle CNC lathe
AMEN~ED SHEE~
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IPEA/US I 4 ~AR 1997
-39-
50 until the stock is properly positioned relative to the
frame (FIGURES 27 and 29).
The internal slide assemblies 220 of the multi-spindle
CNC lathe 50 are mounted on the guide body 308 which is
secured to the wall 112 o~ the casting 106 o~ the ~rame 104
- (FIGURE 11). Therefore, as the stock is indexed under the
~ action of the motor 642, the internal slide assemblies do
not move, but instead remain stationary and in position to
engage the next individual piece of stock which is aligned
therewith.
Likewise, the external slide assemblies 330 are
supported on support brackets 332 which are secured to the
wall 114 of the casting 108 of the frame 104 by threaded
fasteners 334 (FIGURE 12). Therefore, the external slide
assemblies 330 do not move as the stock in indexed under
the action of the motor 642, but instead remained
positioned for engagement with the next piece of stock
which is aligned therewith.
An lmportant feature of the present invention
comprises the fact that the external slide assembly 330 are
adapted to move the cutting tools 336 not only toward and
away from, that is, perpendicular to the rotating stock,
but also along the length of, that is parallel to the
stock. The cutting tools 336 do not comprise forming
tools, but instead comprise general purpose metal working
AMEND~D SH~ET
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tools which may be utilized to form any desired shape in
the external surfaces of the stock pieces. It is therefore
not necessary to remove and replace the tools 336 when
adapting the multi-spindle CNC lathe 50 of the present
invention to the manufacture of a different product.
This in turn means that the multi-spindle CNC lathe
~'50 of the present invention is readily adapted to the Just
In Time, or JIT, manufacturing philosophy in that the lathe
50 may be utilized to manufacture a small number of parts
10and to have the parts a~ailable a~ the precise moment that
they are needed in subsequent manufacturing operations.
The multi-spindle CNC lathe 50 of the present invention is
also readily adapted to the Statistical Process Control, or
SPC, manufacturing philosophy whereby wearing of the tools
15utilized in the internal slide assemblies 220 and the
external slide assemblies 330 is constantly monitored and
adjusted for by actuating the slide assemblies 220 and 330
to assure manufacturing tolerances which are well within
the acceptable range.
20After all of the tools comprising the internal slide
assemblies 220 and all of the tools comprising the external
slide assemblies 330 have completed their respective
functions, the tools are disengaged from the rotating
stock. At this point the piston 180 is actuated to
25disengage the teeth 542 of the spindle carrier 218 from the
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teeth s88, whereupon the motor 642 is actuated to index the
stock into alignment with the next successive work station.
As will be understood by those skilled in the art, one or
more of the spindles comprising the multi-spindle CNC lathe
50 comprises a cutoff station, wherein the finished work is
disengaged from the stock. upon cutoff, of the stock is
selectively advanced through the respective collets under
~,;3 "
the action of increased pressure in the coolant in the
associated tubes 602 and 606.
All of the component parts ~f the multi~spindle CNC
lathe operate under the control of the CNC system 56. In
this manner there is facilitated the use of general purpose
cutting tools, rather than forming tools, which in turn
facilitates the JIT manufacturing philosophy. Likewise,
- 15 the CNC system facilitates the SPC manufacturing philosophy
by constantly repositioning the cutting tools to
accommodate wear.
Although preferred embodiments of the invention have
been illustrated in the accompanying Drawings and described
in the foregoing Detailed Description, it will be
understood that the invention is not limited to the
embodiments disclosed but is capable of numerous
rearrangements, modification, and substitutions of parts
and elements without departing from the spirit of the
invention. 04/25412
hM~NO~D Sl-ic~
