Indexable multi-tool for punch press

An indexable multi-tool for punch presses wherein a plurality of individual punches are held at a singly punching station in a turret-type punch press such that any one of the plurality of punches can be selected upon a rotation of a punch carrier relative to the turret. A striker is carried in the indexable station which does not rotate relative to the turret and which contains an axially extending portion under which the selected punch is positioned in order to be used for punching. Stripper buttons are held on the indexable station by a rotating ring for easy removal and die buttons are held in a die carrier to rotate synchronously with the indexable station.

BACKGROUND OF THE INVENTION 
The present invention relates generally to a turret punch press having a 
pair of upper and lower turrets rotatably mounted to automatically bring 
respective punches and dies into alignment for punching a variety of holes 
in sheet materials and, more particularly, to an apparatus for rotating a 
set of punches and dies at a single punching station in the upper and 
lower turrets for punching a wider variety of holes with the same turret. 
U.S. Pat. No. 4,658,688, assigned to the assignee of the present 
application, discloses a punch press having multiple punch tool rotatable 
turrets wherein at least one of the punch tools on each of upper and lower 
turrets is indexable to different angular orientations. Rotation of the 
indexable punch tools is accomplished by a slidably mounted motor for 
engagement with a timing pulley, which through a timing belt and harmonic 
gear drive, acts to rotate the punch tools. A break and position sensors 
are also provided. Synchronization of punch and die orientation is 
achieved through servos and control. 
U.S. Pat. No. 4,569,267 discloses a punch press which uses a punch tool 
assembly which contains at least two punch pins of different diameters or 
cross-sections which are interchangeable in the working position by a 
control element which is slidable about the pin support member, and 
actuating means. When the punch tool assembly is rotatable about the ram 
to effect the movement of the punch pins from operative to inoperative 
positions, then a cooperating movable die is provided in order to ensure 
that the aligned die bores are cooperatively dimensioned and configured 
with respect to the punch pins. The punch tool assembly is held on the ram 
and moves with the ram and the pins, when not being used, are held in an 
elevated position while the operative pin is rigidly locked into a 
protruding position. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a highly accurate and 
reliable indexable punch and die on a rotatable turret punch press. 
This and other objects of the present invention are embodied in an 
indexable punch press of the type disclosed in U.S. Pat. No. 4,658,688 
noted above, in which there is a further indexing available at at least 
one work station in the turret. An improved die holder is also provided. 
A punch assembly is provided at a punching station in the turret, which 
punch assembly carries a plurality of individual punches. The punch 
assembly may be rotated so that a selected one of the plurality of punches 
will underlie a portion of the striker body acted upon by the ram which 
causes the selected punch to extend downwardly below the punch assembly so 
as to pierce the sheet material being acted upon. 
Stripper buttons are held at a bottom portion of the punch assembly by 
undercut grooves which capture flanges on the buttons and by a rotatable 
circumferential ring extending around the entire periphery of the punch 
assembly which have spaced flanges to selectively overlie and capture the 
buttons. Thus, the buttons may be easily and quickly removed and replaced 
either when damaged, or when the punches are being changed. 
The die holder receives a plurality of corresponding die buttons having 
openings therein corresponding to the punches. The buttons are also easily 
removable and replaceable and are held in specific orientations, as 
required, by keys which may be reversed in orientation. Set screws are 
used to hold the die buttons in place.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring to FIG. 1, the device of the present invention is shown generally 
at 10 and includes a punch press housing 12, a rotatable turret 14, at 
least one indexable punching tool 16, and a punching tool drive motor 18. 
More specifically, a ram 20 (FIGS. 2 and 4) is disposed in the punch press 
housing 12 for driving a punch P through a piece of sheet material M and 
into a die D. A plurality of punches P and dies D are mounted adjacent the 
perimeter of respective upper and lower turrets 14 and 24 which are 
rotatable to bring corresponding punches P and dies D under the ram 20. At 
least one indexable punch tool 16 is mounted within the rotatable upper 
turret 14 and a corresponding indexable die 22 is mounted in the lower 
turret 24 so that the indexable punch 16 and die 22 may be brought into 
registration under the ram 20. 
The indexable punch 16 is provided with a geared bushing 26 that is 
rotatably driven by a harmonic drive gear box 28 which in turn is driven 
by timing belt 30 connecting a pair of pulleys 32 and 34. The servo motor 
18 is mounted on the punch press housing 12 by a vertical slide 36 and is 
selectively engageable to the drive pulley 32. Vertical movement of the 
servo motor 18 in the slide 36 is provided by an actuator 38 such as a 
pneumatic actuator, connected between the motor slide 36 and the punch 
press housing 12. The servo motor 18 may be locked into its respective 
upper and lower positions by a slide lock mechanism 40. A resolver 41 
provides feedback from the motor 18 to a programmed controller (not shown) 
to monitor the angular rotation of the motor 18. 
FIG. 2 shows the motor 18 slidably mounted on the housing 12. The pneumatic 
actuator 38 is connected at an upper end thereof to the punch press 
housing 12 by a bracket 42. An extendable arm 44 of the actuator 38 is 
connected by a clevis 45 to a slide plate 46 on which the motor 18 is 
mounted. The slide plate 46 slides vertically within slide rails 48 and 50 
so that the motor 18 may be selectively engaged with the driver pulley 32. 
Coupling between the motor 18 and the driver pulley 32 is accomplished by a 
coupling 52, such as a helical single flex coupling. The helical coupling 
is connected at one end thereof to a shaft 54 of the motor 18 and at the 
other end thereof to a shaft and tang arrangement 56 which engages a 
shaped opening 58 in the drive shaft 78. The helical coupling 52, such as 
coupling made by Helical Company, includes a helical spring (not shown) 
that provides relatively rigid torsional connection between the shaft 54 
and the tang and shaft assembly 56, yet which gives relatively easily in a 
vertical direction so that misalignment of the motor 18 with the drive 
pulley 32 is accommodated while still transmitting the torque of the motor 
18. 
The slide plate 46, and the motor 18 mounted thereto, may be locked in 
either the coupled and uncoupled positions by a motor slide lock 40 
mounted on the punch press housing 12. The motor slide lock 40 includes a 
shot pin 60 which is selectively insertable into a bracket 62 mounted on 
the slide plate 46. The bracket 62 includes first and second openings 64 
and 66 through which the shot pin 60 is inserted to lock the slide plate 
46 and motor 18 into the respective coupled and uncoupled positions. 
Movement of the shot pin 60 is controlled by an actuator 67, such as a 
pneumatic actuator. 
An adjustable mechanical stop 68 is provided on the slide 36 in the form of 
a vertically disposed bolt 70 extending through an arm 72 on the slide 
plate 46. The bolt 70 abuts a flange 74 extending from the punch press 
housing 12 when the motor 18 and slide plate 46 are in the engaged 
position. A lock nut 76 is provided on the bolt 70 to lock the bolt 70 
into position. The stop 68 prevents excessive vertical loading on the 
coupling 52. 
When the motor 18 is in the coupled position, the helical coupling 52 
provides torsional coupling between the motor shaft 54 and the drive 
pulley 32. The drive pulley 32 is fixed to the pulley shaft 78 which is 
mounted for rotation about a vertical axis by bearings 80 within a bearing 
housing 82. The bearing housing 82 is fastened to the turret 14. 
The toothed timing belt 30 extends between the drive pulley 32 and the 
second pulley 34. Each of the pulleys 32 and 34 are toothed, corresponding 
to the teeth on the inner surface of the timing belt 30, thereby providing 
positive rotational drive between the pulleys 32 and 34. The second pulley 
34 drives the harmonic gear drive 28. The harmonic gear drive 28 drives 
the geared bushing 26 on the indexable punch 16 to provide rotation 
thereof. 
The indexable punch 16 is provided with an annular lifter ring 88 extending 
therearound which is connected to lifter springs 90 extending from the 
turret 14 to the lifter ring 88. The ram 20 is shown above the punch 16 
and during operation will drive the punch 16 through a piece of sheet 
material M and into the die 22. The lifter ring 88, in conjunction with 
the springs 90, then returns the punch 16 to its original position, 
lifting it from the sheet material M. 
A portion of the lower turret 24 is also shown in FIG. 2. It includes the 
indexable die 22 which is rotated by a harmonic gear drive 92 which in 
turn is driven by a timing belt 94 that is driven by a vertically slidable 
motor (not shown) slidably mounted on the punch press housing 12 below the 
lower turret 24. The motor is coupled to a drive pulley 96 by a helical 
coupling 98. The harmonic drive 92 extends into the lower turret 24 and 
includes an output gear 100 engaging a geared bushing 102 encircling the 
die 22. An anvil portion 97 of the punch press 10 can be seen supporting 
the lower portion of the turret 24 to resist the downward force of the ram 
20 as it pushes the punch P through the sheet material M and into the die 
22. 
A proximity switch 104 is mounted to the housing 12 and senses a target 106 
on the lifter 88 to indicate that an indexable station has retracted from 
the material M and is safe to move the material M. Once the turret is 
positioned under the ram 20, a home position of the indexable punch 16 is 
established by a second proximity switch (not shown) mounted on the 
housing 12. A vane (not shown) extends from the punch bushing 26 to 
activate the proximity switch when the bushing 26 and the punch 16 are 
rotated to home position. There are other sensors (not shown) to indicate 
that an indexable station is positioned below the ram 20. These sensors 
are of proximity type and mounted on the frame 12. A target on the bushing 
of the die 22 is selectively sensed by a frame mounted switch (not shown). 
To prevent damage to the frame mounted switch it is preferably mounted on 
a pneumatic cylinder so that it may be moved toward the die 22 to sense 
the target and then move away before operation of the ram 20 or rotation 
of the turret 24. 
FIG. 3 shows the upper turret 14 from above including a plurality of 
punches P. The slide plate 46 is mounted between the V-shaped slide rails 
48 and 50. The pneumatic actuator 38 is seen suspended from the bracket 42 
and the slide lock 40 and the arm 72 of the mechanical stop 68 can be seen 
more clearly. The timing belt 30 extends from the drive pulley 32 to the 
second pulley 34 under the housing 12. The harmonic gear drive 28 is 
enclosed by a housing 108 having a shaped opening 110 through which 
extends the geared bushing 26 of the indexable punch 16. The indexable 
punch 16 is keyed to the geared bushing 26 by a key 114. The turret 14 is 
rotatable about a turret axis 116 to bring other punch tools P under the 
ram 20. 
FIG. 4 shows the punching tool 16 in greater detail as it is positioned 
below the ram 20 in a ready to work position. The punching tool 16 
comprises a top striker cap 120 which is engaged by the ram 20 during a 
punching operation. The cap is secured to a striker body 122 by 
appropriate fastening means 124 such as threaded fasteners (see also FIG. 
5). The striker cap 120 has a plurality of apertures 126,128 therethrough 
to permit the introduction of lubricating oils into the interior of the 
punching tool 16. The striker body 122 is generally annular in shape and 
as seen in phantom in FIGS. 5 and 7, includes a radial arm 130 which 
overlies a selected one of the punches P carried in the punching tool 16. 
The radial arm 130 extends axially downwardly from a main upper annular 
portion 132 of the striker body, thus leaving a relieved area 134 in the 
remaining circumferential area below the main upper body portion. The 
striker body 122 is vertically reciprocably carried in a lift sleeve 
member 136 and is prevented from rotating relative to the lift sleeve 
member by appropriate guide means 138 such as a vertical groove 140 formed 
in the striker body 122 and a guide pin 142 carried by the lift sleeve 
member 136. Thus, the striker body 122 will be free to move vertically 
relative to the lifter sleeve, however, will be prevented from rotating 
relative thereto. 
The lifter sleeve member 136 is in turn held against rotation relative to 
the lifter ring 88 by appropriate guide means 144 such as a retainer clip 
146 mounted on the lifter sleeve member 136 by appropriate fastening means 
147 such as threaded fasteners. The retainer clip straddles a bracket 148 
on the lifter ring 88 (FIG. 5). Thus, the lifter sleeve member 136 will be 
free to move vertically relative to the lifter ring 88, however, will be 
prevented from rotating relative thereto. 
The lifter sleeve member 136 is normally supported on a stripper guide 150. 
The stripper guide 150 forms a lower outer portion of the indexable punch 
16 and includes vertical passages 149 for receiving a lower portion of the 
punches P. The stripper guide also removably receives stripper buttons 151 
as described in greater detail below. The stripper guide 150 is vertically 
reciprocally positioned within the geared bushing 26 and is keyed to that 
bushing by appropriate guide means 152 such as a radially projecting pin 
154 carried by the stripper guide 150 which is received in a vertical slot 
156 in the bushing 26. Thus the stripper guide 150 will be free to move 
vertically relative to the bushing 26, however, will be prevented from 
rotating relative thereto. 
The stripper guide 150 surrounds a punch carrier 158 and is keyed thereto 
by appropriate guide means 160 such as a radially inwardly projecting 
guide pin 162 which is received in a vertical slot 164 formed in the punch 
carrier 158. Thus, the punch carrier 158 will be free to move vertically 
relative to the stripper guide 150, however, will be prevented from 
rotating relative thereto. 
The punch carrier 158 has a plurality of vertically oriented passages 161 
in which are received upper portions of the punches P. The punches P each 
have an enlarged head H which is received in an annular recessed area 163 
formed at the top end of the punch carrier 158. A shoulder 165 is thus 
formed at the surface formed by the recessed area which supports the head 
H of the punch P. The stripper guide 150 extends to an elevation above the 
head H of the punches and a retaining ring 166 is snapped into a groove 
167 in the stripper guide to closely overlie the heads H of the punches. 
Each of the punches P normally has a key K which is received in a vertical 
slot 168 in the punch carrier 158 to keep the punch angularly oriented 
within the punch carrier 158. This is particularly required when the punch 
P does not have a circular working end W. If the punch P has a working end 
that could be oriented to give different shapes upon a 90.degree. 
rotation, two vertical slots 168 might be provided (See FIG. 7). 
A center post 170 is used to hold the punch carrier 158 against the striker 
body 132. The center post 170 is positioned within a central vertical 
passage 172 in the striker body 132. The central vertical passage 172 
includes an annular shoulder 174 which projects into the passage 172 and 
the post includes a post cap 176 which is removably secured to the post 
170 by appropriate fastening means 178, such as a threaded fastener, such 
that the post will be prevented from moving downwardly relative to the 
striker body 132 once the cap 176 engages the shoulder 174. 
The post 170 also has an annular shoulder 180 formed thereon which is 
positioned below the striker body shoulder 174 and which overlies the 
punch carrier 158. The punch carrier 158 is pressed against the post 
shoulder 180 by means of appropriate biasing means 182 which may be in the 
form of a conical spring or Belleville washer. A bottom end of the post is 
secured to the stripper guide 150 by appropriate fastening means 184, such 
as a threaded fastener. In this manner, the entire punch tool assembly is 
held together. 
In operation, as the ram 20 descends, it strikes the striker plate 120 and 
causes the entire punch 16 to move downwardly, including the lifter ring 
88, which moves downwardly against the bias of the lifter springs 90. When 
the entire punch assembly has moved downwardly enough to cause the 
stripper buttons 151 to engage the sheet material M, as shown in phantom 
in FIG. 4, compression of the biasing means 182 occurs, causing the punch 
carrier 158 to move downwardly relative to the stripper guide 150. As this 
occurs, the striker body 122, through the projection 130, continues to 
press against one of the punches P, resulting in that punch being extended 
beyond a bottom of the stripper button 151. The remaining punches are not 
engaged by the extension 130, but rather by skid posts 190 which are 
carried on the striker body 132 in the recessed area 134. The skid posts 
190 are normally biased downwardly by biasing means 192 which may be in 
the form of a coil spring 194. The coil spring is captured in a vertical 
passage 195 between an enlarged end 196 of the skid posts 190 and a plug 
or cap 198 normally sealing the opening 128 to the passage 195. The cap 
198 can be pressed downwardly to provide access to the passage 195 to 
introduce lubricants thereinto, and, upon release of the cap 198, it will 
return upwardly to a sealing position to prevent entry of contaminants 
into the passage 195. The springs 192 are weaker than biasing means 182 
and therefore, once the other punches engage the sheet material M, those 
other punches will stop their downward movement relative to the material 
M. Only the ram 20, striker plate 120, striker body 132, stripper guide 
150 and the individual punch under the extension 130 will continue the 
downward movement to pierce through the material M. 
When the ram 20 has terminated its downward stroke and begins to move 
upward, first the extended punch will move upwardly by action of the 
biasing means 182 and then the entire punch assembly 16 will move upwardly 
by action of the lifter springs 90. 
As best seen in FIGS. 4 and 6, the stripper buttons 151 are held in place 
on the lower end of the stripper guide 150 by means of undercut slots 220 
which receive a flange 222 of the buttons 151 around one half of their 
circumference. An open side of the slot, opposite a bight 224 thereof, is 
selectively closed by a rotatable ring 226 having spaced inturned flange 
sections 228 which will overlie the button flanges 22 when the ring is 
properly rotated. A detent member 230 is carried by the punch carrier 150 
and has a projection 232 projecting downwardly into one of a plurality of 
spaced recesses 234 formed in the ring to selectively hold the ring in a 
desired orientation. Thus, the ring can be moved from a locking position 
where the ring flanges 228 overlie the button flanges 222, or to a 
position where the ring flanges 228 are spaced between the slots 220 such 
that the buttons 151 will be free to be removed from the punch carrier 
150. 
FIGS. 2 and 8 illustrate the dies D which are positioned below the punches 
P. The dies include removable and replaceable die buttons 240 having 
openings 242 which correspond to the overlying punches. The die buttons 
240 are held in a die carrier 244 and are keyed to specific angular 
orientations (when the die opening is not circular) by reversible keys 246 
which engage into a selected slot or recess 248 in the particular die 
button 240. Die buttons which have openings 242 that may be oriented 
differently (rectangular as opposed to square) have more than one slot 248 
to correspond to the different possible orientations. Set screws 250 are 
provided to lock the buttons 240 in place and to prevent them from lifting 
out of the die carrier 244 when the punch is retracted from the die D. The 
keys 246 have a rectangular shape and are secured by means of a threaded 
fastener 252 extending through said key at a location spaced from a center 
of the key, such that, as measured from said fastening location, said keys 
have a long end 254 and a short end 256. Since the keys 246 are 
reversible, when a button 240 is used which has a circular opening 242, 
the orientation of the key 246 is reversed presenting the short end 254 
toward the button 240 which terminates short of the button 240. Otherwise, 
the long end 256 of the key is oriented toward the button 240 so that it 
will extend into the slot 248. 
The apertures 126 and 128 were identified above as providing inlets for 
lubricating oils. From aperture 126, which communicates with the passage 
172 formed in the center of the striker body 122, oil is permitted to flow 
between the push cap 176 and the striker body shoulder 174 in a small 
passage 260 which communicates with a spiral oil groove 262. The oil that 
is permitted to flow down between shoulder 180 on the post and the striker 
body 122 through a small passage 264 onto a top of the punch carrier 158. 
A plurality of radial grooves 266 are provided on the top surface of the 
punch carrier 158 (see FIG. 7) to permit passage of the oil radially along 
the top of the punch carrier. A spiral oil groove 268 is also provided in 
a central passage 270 of the punch carrier 158 to permit oil to flow down 
through the area of the biasing means 182. 
Oil flowing radially through the passage 266 on the top of the punch 
carrier 158 is permitted to continue a downward flow through a spiral 
groove 272 formed on an outer circumference of the punch carrier 158 which 
normally abuts against the stripper guide 150. This oil then flows down 
around the working end W of the punch as does the oil flowing through the 
area of the biasing means 182. An additional spiral oil groove 274 is 
provided on the outer circumference of the stripper guide 150 to permit 
lubrication between the stripper guide and the geared bushing 26. Thus, 
lubricating oil is provided between all of the sliding surfaces to reduce 
friction and heat build up within the punch assembly. 
Rotation of the geared bushing 26 by the punch press control means causes 
rotation of the portion of the punch assembly 16 below the striker body 
122 which thus moves a selected punch P into a working position below the 
striker extension 132 while disposing the other punches carried in the 
stripper guide 150 in an inactive position under the recess 134. The 
movable skid posts 190 and retainer ring 166 prevent the inactive punches 
from bouncing upwardly in the punch carrier in response to vibrations of 
the punch. In this manner, only one punch is moved to a working position 
while all of the other punches are held in an inactive position. 
As is apparent from the foregoing specification, the invention is 
susceptible of being embodied with various alterations and modifications 
which may differ particularly from those that have been described in the 
preceding specification and description. It should be understood that I 
wish to embody within the scope of the patent warranted hereon all such 
modifications as reasonably and properly come within the scope of my 
contribution to the art.