Punch machine

United States Patent tm 3,528,331

<td> [72] [21] [22] [45]</td><td> Inventor Gerald S. Ikelheimer 1215 Fifth Ave., New York, New York 10029 Appl. No. 698,639 Filed Jan. 17,1968 Patented Sept. 15,1970</td>

<td> [54]</td><td> PUNCH MACHINE 13 Claims, 11 Drawing Figs.</td>

<td> [52]</td><td> U.S.CI........................................................ 83/145, 74/600, 83/525,100/257</td>

<td> [51]</td><td> Int.Cl................... B26fl/02</td>

<td> [50]</td><td> Field of Search.................................... 83/525, ....... 527,145; 100/257; 74/600</td>

[56] References Cited

UNITED STATES PATENTS

548,017 10/1895 Stuebner...................... 83/525

1,035,093 8/1912 Kraut........................... 83/525

1,977,795 10/1934 Gray............................. 83/145

Primary Examiner—James M. Meister Attorney—March, Gillette and Wyatt

ABSTRACT: A punch press having an automatic reset adjustable to halt the punch at a selected starting position at the end of each cycle and including a clutch, a drive shaft and an eccentric, any of which can be angularly offset with respect to the others to change the starting position of the punch.

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Patented Sept. 15, 1970

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PUNCH MACHINE

In the embodiment in FIG. 1, the punch machine has a stationary frame 11 in which a shaft 12 is journalled. One end of the shaft is connected to a flywheel 13 driven from a motor (not shown) by a belt 14. The flywheel 13 is connected to the shaft by way of a clutch generally indicated by reference character 16. At the other end of the shaft is a plate 17 keyed to the shaft 12 by a key 18 and connected to an eccentric 19 by means of one or more bolts 21 that pass through an arcuate slot 22 in the plate 17 and thread into the eccentric 19. A connecting rod 23 fits over the eccentric 19 and is connected at its lower end with a punch which is not shown in this drawing. Between two sections of the frame 11 is a brake 24 having a lining 26 that bears rather loosely upon the shaft 12 at all times but which provides sufficient friction to stop the shaft 12 as^soon as the clutch 16 disengages the shaft from the flywheel

The clutch 16 is attached in a fixed orientation on the shaft 12 by means of a key 27 and engages the flywheel 13 by means of a dog 28 positioned to fit into a recess in the flywheel 13. The dog 28 slides back and forth in a slot 31 in the clutch 16 and is pushed toward the recess 29 by a spring 32. However, except when the press is being operated in a power stroke, the dog 28 is prevented by a clutch wedge 33 from entering the recess 29. The clutch wedge 33 is pivoted on the frame 11 and when it is moved out of the way, the dog 28 slides against the face 34 of the flywheel 13 and into the recess 29 when the flywheel is rotated to the correct position by the driving belt 14.

FIG. 2 shows a cross-section of the clutch and flywheel along the lines 2—2 in FIG. 1 to illustrate the operation of the clutch. As may be seen, the dog 28 has a sloping face 28α which engages a sloping face 33α on the clutch wedge 33 as the clutch 16 rotates. In order for the sloping face 33α to engage the face 28α, the clutch 16 has a groove 34 which is deep enough to expose the lower surface of the dog. The engagement between the surfaces 28α and 33α causes the dog 28 to be retracted against the pressure of the spring 22 and thereby disengaged from the flywheel 13 at the end of one revolution from the time the clutch was engaged.

FIGS 3 through 6 show a punch 36 which is connected to the lower end of the connecting rod 23 and operated in conjunction with a die, or platen, 37. The punch passes between two sections 38α and 386 of a stripper and must be aligned with a hole 39 in a pattern 41 which must be held in a fixed position with respect to a workpiece 42. FIG. 3 shows the punch 36 at its rest position and the workpiece 42 and pattern 41 resting on the die 37. The workpiece 42 and the pattern 41 may be held together by hand or they may be clamped together by any other suitable means, but in any case it is necessary for the pattern to be precisely located with respect to the punch 36 in order to prevent the punch from chipping away the edge of the pattern or, in the case of a very hard pattern, from being ruined by it. Heretofore what has happened is that the operator has been forced to actuate the punch driving mechanism by hand to move the punch down until it enters the appropriate hole in the pattern 39, and then return the punch to its uppermost position from which the punching cycle itself can start upon operation of the punch control. It is time-consuming to have to run the punch down into the pattern by hand and there is always the possibility either that the pattern 41 will slip with respect to the workpiece 42 or that both of them will slip with respect to the punch 36, and if that happens the punch will strike the wrong place when it is operated by its drive motor. FIG. 4 shows the same apparatus with the punch in the same position as in FIG. 3, but with the workpiece 42 and the pattern 41 elevated enough for the punch 36 to extend into the opening 39 of the pattern. Since the starting position of the punch 36 has, in accordance with the present invention, been set so that there is very little more space than is absolutely needed between the bottom of the punch 36 and the top of the die 37, it is not necessary to lift the pattern 41 and workpiece 42 very far for the pattern to engage the punch. The punch starts its power stroke from this position without ever being disengaged from the pattern and

This invention relates to a power punch machine and particularly to means for adjusting the operating cycle so that the punch can be stopped at any point of its stroke and not just at top dead center.

The punch machine operates by moving a punch into a die and retracting the punch, preferably through a stripper. A workpiece to be punched is placed between the stripper and the die so that as the punch is withdrawn, the workpiece will be separated from it by the stripper.

One way in which punch machines are commonly used requires a pre-punched pattern to be placed in contact with the workpiece between the latter and the stripper so that the punch can be guided precisely into exact locations on the workpiece. However, in ordinary punch machines in which the punch starts at its uppermost position, moves down into the workpiece, and then returns to stop at the uppermost position, it is difficult to align the punch with the pattern. While the alignment may be done by hand-operating the mechanism to move the punch down into the pattern, the pattern and workpiece must then be held in that exact position while operating the punch by means of its normal power source. If the workpiece and pattern are held stationary, the punch, in following its fixed path of travel, will enter the workpiece at 25 the proper location determined by the pattern, but there is a chance that either the workpiece or the pattern or both will move slightly between the time they are aligned with the punch and the time the actual punching operation is carried out, and in any case it is tiring to the operator to align the 30 punch and the pattern by hand, and the aligning procedure increases the total cycle time for each operation.

In accordance with the present invention, the punch is halted at a point on its stroke below top dead center and in fact with the tip of the punch somewhat below the level of the 35 stripper. The workpiece and pattern can then be held against the punch rather than being allowed to rest on the die. In this position of the pattern and the workpiece, the punch extends at least partly into the pattern before the power stroke begins. When the power stroke is initiated, the punch presses 40 downwardly through the already-aligned pattern and into the workpiece, forcing the latter against the die and completing the punching operation. Thereafter, the punch moves away from the workpiece and die to its top dead center position and back to the initial position at which it is halted in readiness for 45 the next cycle of operation.

The principal object of the invention is to provide an improved punch press which simplifies the aligning and punching operations and minimizes the time required for a complete cycle of operation. Further objects will become apparent from 50 the following specification.

The punch machine of the present invention includes a drive shaft with means to actuate a punch and means, such as a flywheel, to drive the shaft. The machine also includes coupling means to connect the drive means to the shaft. Any 55 of the foregoing means connected to the drive shaft may be arranged for angular adjustment relative to the shaft to provide the necessary adjustable structure to control the starting and stopping positions of the punch at any desired point in its range of travel.

The invention will be described in greater detail hereinafter in connection with the drawings in which:

FIG. 1 is a fragmentary view partly in cross section of one embodiment of the invention;

FIG. 2 shows another view of the clutch in FIG. 1;

FIGS. 3 through 6 show various steps in a cycle of operation of the punch in the embodiment of FIG. 1;

FIG. 7 shows the adjustment structure used in the embodiment of FIG. 1;

FIG. 8 shows a different adjustment structure for a modifi- 70 cation of the invention;

FIG. 9 shows a different adjustment structure for another embodiment of the invention; and

FIGS. 10 and 11 show yet another embodiment of the invention.

3,528,331 therefore as long as the workpiece 42 does not shift with respect to the pattern 41, the punch 36 will of necessity enter the workpiece at exactly the proper location. FIG. 5 shows the same apparatus after a cycle has been initiated and in fact after the punch 36 has knocked out a wafer 43 from the appropriate spot in the workpiece 33. Thereafter, and essentially in a continuous motion, the punch 36 retracts to the top dead center position shown in FIG. 6 and then moves downward until it stops at the starting position shown in FIG. 3. On the way up to the top dead center position in FIG. 6, the pattern 41 and the workpiece 42 are pulled free of the punch by the stripper 38α and 38b.

FIG. 7 shows a fragment of the plate 17 in FIG. 1 depicting the arcuate slot 22 and the bolt 21 that joins the plate 17 to the eccentric 19. By loosening the bolt 21, the eccentric 19 may be rotated on the shaft 12 to any desired position within the limits of the slot 22 to adjust the angular position that the eccentric will occupy when the shaft stops under a dragging force of the brake 24 in FIG. 1.

FIG. 7 depicts in enlargement the adjustable joining feature of the invention. Arcuate slot 22 is shown in disc 17 with the head of bolt 21 tightened against the disc. Since, as was shown in FIG. 1, the disc 17 is fixedly attached to the shaft 12, rotation of the disc 17 relative to the eccentric 19 changes the vertical position of the connecting rod 23 and the punch 36 connected thereto. Furthermore, since both the disc 17 and the clutch 16 are fixedly attached to the shaft 12, the vertical location of the connecting rod 23 at the time of disengagement of the clutch 16 is determined by the setting of the disc 17 with respect to the eccentric 19. The relative setting between the disc 17 and the eccentric 19 can then be fixed by tightening the bolt 21.

A more detailed view of the relationship of the eccentric 19 to the trip punch cycle is shown in FIG. 8. The connecting rod 23 is mounted on the eccentric 19 and linked to a ram 44 by a ball 46 that fits into a socket or equivalent in the ram 44 whereby the rotational motion of the shaft 12 may be converted and a translational motion imparted to ram 44. The lower end of ram 44 is adapted for the removable attachment of the punch 36.

FIG. 8 depicts a somewhat different eccentric joining feature than FIG. 1 in that a second disc 47 is interposed between the disc 17 and the eccentric 19 and is rigidly attached to the eccentric. An arcuate slot 22α in disc 47 rather than in the disc 17 and the bolt 19 is threaded into the latter.

FIG. 8 also shows the means for attaching the stripper members 38α and 38b adjustably to the frame 11 in such a manner that both vertical and horizontal adjustments are possible. The only requirement of the stripper members is that they hold back the pattern and the workpiece when the punch 36 moves up to its topmost position; it is not normally necessary that the stripper members have any particular configuration. As shown in FIG. 8, the stripper members 38α and 38b are short bars attached to the bottom end of cylindrical rods 51 and 52, respectively. These rods extend into suitable channels 53 and 54 in the frame 11 and are secured in place by a pair of set screws or fasteners 56 and 57. As shown, the proximal ends of the members 38α and 38b are far enough apart to permit the largest part of the punch 36 to fit between them. If a larger punch is to be used, it is merely necessary to loosen the set screws 56 and 57 and rotate the cylindrical rods 51 and 52 to separate the members 38α and 38b so that their ends will be farther apart although they will also be offset with respect to the punch 36. If desired, of course, separate stripper members may be made up for each punch and held in place by the same set screws 56 and 57.

Whereas the punch machines shown in FIGS. 1 and 8 provide for adjustment of the starting position of the punch by rotation of the eccentric 19 relative to the shaft 12 and the clutch 16, which is fixedly oriented on the shaft, FIG. 9 shows a modified embodiment in which the eccentric 19 is fixedly oriented on the shaft 12 and means are provided to vary the angular orientation of the clutch 16. In FIG. 9 the clutch is de40 picted in simplified form, but it is the same structure as was shown more completely in FIGS. 1 and 2. In FIG. 9, the disc 58 is fixedly oriented on the shaft 12 by means of a key 59. Basically, the disc 58 is similar to the disc 47 in FIG. 8 and is provided with a slot 22α through which the bolt 21 extends and is threaded into the body of the clutch 16. The clutch itself is not keyed to the shaft 12 and thus loosening the bolt 21 and rotating the clutch body 16 relative to the disc 58 sets the orientation at which the clutch will engage and disengage from the flywheel 13. This in turn determines the starting (and stopping) position of the punch 36 so that the punch may be stopped below top dead center just as in the previous embodiments.

A further embodiment of the invention is portrayed in FIGS. 10 and 11 wherein the assembly of the eccentric, shaft and clutch is varied angularly relative to the adjusting disc. This embodiment employs a clutch wedge 59 pivoted on an adjusting disc 61 by means of a pin 66, as illustrated in FIG. 11, rather than the main housing 11 as in FIG. 1. As shown in FIG. 10, a dog 28 similar to the one in FIGS. 1 and 2 is slidably inserted in a longitudinal, eccentric recess in the clutch 16 and is biased outwardly by the spring 22 in the direction of a recess 29 in the transverse face of flywheel 13 which is mounted to be freely rotating on the shaft. A groove 28b in the dog 28 mates with the groove 34 in the cylindrical face of the clutch 16 whereby the clutch wedge 59 may be inserted to prevent longitudinal movement of the dog 28. A trip cam 62 is interposed between the adjusting disc 61 and the clutch 16 and comprises a peripheral arcuate flange 63 with a ratchet or toothed inner surface 64. The latter extends longitudinally beyond the transverse plane of the clutch wedge 59 to permit contact with ratchet wedge 65. As clearly shown in FIG. 11, a pin 66 pivotally joins the ratchet wedge 65 to the clutch wedge 59 and is fixedly connected to the adjusting disc 61 as aforementioned. A bar 67 laterally extends from the adjusting disc 61 against which a spring 68 biases the clutch wedge 59 into the dog groove 28b. A lateral projection 69 on the ratchet wedge 65 is adapted to extend over the top of the clutch wedge 59 whereby activation of a trip lever 70 will rotate the ratchet 64 clockwise and cause the ratchet wedge 65 and the clutch wedge 59 to pivot as a unitary assembly about the pin 66, depressing the spring 68 and releasing the dog 28. Engagement of the dog 28 with the recess 29 in the flywheel 13 initiates the trip punch cycle.

Loosening the bolt 21 permits rotation of the adjusting disc 61 within the limits of the adjusting slot 22. As the pivotal pin 66 of the clutch wedge 59 is affixed to the adjusting disc 61, it is clear that rotation of the adjusting disc 61 is attended by adjustment of the angular position of the clutch wedge 59 and concomitantly by adjustment of the position at which the ram of the punch stops. Preferably, when the adjustment is made, the flywheel 13 is not rotating so that adjustment of the clutch wedge 59 away from the dog 28 may cause the dog 28 to engage the flywheel 13. Thus, when the flywheel 13 is rotated the punch cycle is immediately initiated without actuation of the trip lever 70. The rotating trip cam 62 can be actuated by the trip lever 70 to rotate the clutch wedge 59 through its arc at any point in the full range of adjustment of the adjusting disc 61.

In order to disengage the dog 28 from the recess 29 in the flywheel 13 at the end of a cycle, the dog 28 has a wedge surface 28α which mates with a complementary wedge surface 59α on the clutch wedge 59. At the end of the cycle the trip lever 70 and the trip cam 62 have been released, thereby allowing the spring 68 to bias the clutch wedge 59 back up into the groove 34 in the clutch 16. Accordingly, as the dog 28 is rotated at the completion of the punch cycle, the wedge surface 28α of the dog 28 comes into contact with the wedge surface 59α of the clutch wedge 59, thereby moving the dog out of the recess 29 in the flywheel 13. A brake, such as that shown in FIG. 1, is provided to stop the rotation of the shaft 12.

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While the invention has been shown and described in connection with various preferred embodiments, it is expressly understood that the invention is not limited thereto but may be otherwise variously embodied within the scope of the following claims.