WO1993006978A1

WO1993006978A1 - Punch press and method of using same

Info

Publication number: WO1993006978A1
Application number: PCT/US1991/007593
Authority: WO
Inventors: Robert E. Reimbold
Original assignee: William H. Reimbold D.B.A. Anaheim Automation
Priority date: 1991-10-11
Filing date: 1991-10-11
Publication date: 1993-04-15

Abstract

A rotatable turret die (67) is used to punch a series of holes (7A, 7B, 7C) in a metal sheet (W). An edge clamp (40, 126) grips an edge of the sheet to move it transversely beneath the turret die (67) for making the holes. The sheet is then clamped by turret clamping means (75, 98) and the edge clamp is released. The sheet is then rotated together with the turret clamp to a position where a second edge of the sheet is gripped by the edge clamp. The turret clamp is then released so that the workpiece may be moved transversely together with the edge clamp so that additional holes may be punched in the sheet, including holes in the portion of the sheet initially gripped by the edge clamp. Support tables (120a, 120b, 122) support the sheet while it is being punched and rotated, including a fixed table (122) that extends beneath the edge clamp and the turret clamp, and a pair of side tables (120a, 120b) that move with the edge clamp when the edge clamp is moved toward and away from the turret clamp.

Description

PUNCH PRESS AND METHOD OF USING SAME

Technical Field 5 The present invention relates generally to material processing machines and, more particularly, to punch presses

¥ and methods of using them.

Background Art Punch presses of various types, adapted for numerous

10 different purposes, are well known. Such presses operate on sheetlike workpieces, as for example, 14 gauge BBBB mild steel or 0.125 aluminum, to form preselected, distinctly shaped openings in the workpiece. In this manner, the finished piece may be used in a wide variety of commercial products. It is

15 well recognized that many applications require a significant amount of precision, and repeatability, in the location of the openings in the workpiece, i order to ensure compatibility with modern assembly practices for such goods as instrument panels, electronic equipment enclosures, and the like.

20 In general, punch presses are electrically operated, having a pneumatic mechanism for driving a punching tool through the workpiece. The press may be manually operated or automated and driven by computer generated commands.

Conventional punch presses often utilize a variety of

25 various shaped tools or dies, disposed in a rotatable die turret assembly, for performing the punch operations. The workpiece is placed horizontally on a support surface and moved along the X and Y axes to permit punch operations to be performed at preselected locations on the workpiece. The die

30 turret may be rotated during the punching process so that a selected one of a number of dies may be moved into position for performing the punching operation. Of course, in order to obtain a suitable, accurately punched final product, it is very important that the workpiece be securely held and

35 precisely positioned during the punching process.

'.

In conventional presses, the workpiece is often supported during the punching operation by a support plate including a

UBSTITUTE SHEET die shoe having a shape for receiving the die. In this manner, a clean, precisely shaped hole may be formed in the workpiece, while deformation of the workpiece is minimized, or in some cases, eliminated. When a rotating die turret having a number of dies is utilized, the die turret is generally linked to a support plate so that an appropriately shaped shoe in the support plate is available to receive the particular die being used.

With regard to conventional methods for controlling and positioning the workpiece for punching operations, reference may be made to U.S. Patent Nos. 4,573,861; 4,630,461; 4,198,845 and 3,834,213. The disclosures in these patents, and a review of conventional presses, quickly reveal a recognition of the requirement for precise control of the workpiece during the punching process. This control is necessary, not only for precisely positioning the workpiece for accurate punching, but for securely holding the workpiece throughout the punching operation.

The requirement for precise workpiece control in conventional presses necessitates the use of clamping devices for securely holding the workpiece. The portion of the workpiece being clamped, sometimes comprising as much as about

10 percent of the workpiece material, is not accessible to the die turret for punching operations. As a result, the unpunched material is often sacrificed, thereby increasing the costs of the press operation and generating unwanted and frequently unusable scrap. In view of this fact, it would be highly desirable to have a punch press capable of accurate workpiece control while reducing, or eliminating the need to sacrifice substantial portions of workpiece materials.

Of course, in some conventional punching operations, when there is a desire to conserve the workpiece material, the punching operation can be interrupted so that the workpiece can be repositioned in relation to the clamping mechanism. While this action may result in the conservation of material, it is time consuming, thereby increasing labor costs. In addition, this action can result in an increase in quality control problems, since the workpiece, if not precisely repositioned after the interruption, will often end up with misaligned, and unsuitable, punched holes. In such cases, the desire to conserve material is sometimes not realized because of a higher rejection rate for the finished product. In view of the foregoing, it would be most desirable to have a punch press which could reduce losses due to waste, in an effective and efficient manner, while also reducing labor costs and the number of steps to perform a punching operation. Summary of the Invention

The present invention is a punch press which allows the punching operation to be performed over substantially all of the surface of the workpiece material, thereby reducing or eliminating losses of unused material. The punch press has a rotatable die turret for punching holes in the workpiece. A workpiece edge clamp positions the workpiece in relation to the die turret by X-Y translation in the horizontal plane. A turret clamp, disposed coaxially in relation to the die turret, is configured to clamp and rotate the workpiece about the turret axis, thereby making substantially all of the workpiece surface area available to the die turret for the punching operation. The turret clamp allows the edge clamp to be repositioned, thus exposing the previously unavailable clamped region. The finished piece is punched to net shape. Another advantage of the present invention is that it eliminates the need for reshearing of the workpiece. Because there is no unused material, the initial blank can have the exterior dimensions of the finished piece, thus eliminating the need for further shearing. Advantageously, this efficient punch press is capable of repetitive punching operations while reducing the number of manual operations during the punching process. The material and turret clamps are computer controlled for fast and accurate workpiece manipulation. In one embodiment, the punch press centers the workpiece under the turret axis as a reference location before every rotation. Alternatively, in a preferred embodiment, the punch press references one edge at

SUBSTITUTE SHEET the start of operation and proceeds to punch and rotate the workpiece without any further location referencing. This reduces the material set-up time due to only having to ensure the accuracy of one reference edge, while providing only an approximately accurate outline for the other edges. The control software capabilities are such that subsequent repositioning of the workpiece is done automatically and the holes punched are all positioned relative to the initial reference edge. No other manual adjustments are necessary. A further advantage of the present invention is its capability to automatically rotate and accurately punch both smaller and larger pieces than previous designs. In the preferred embodiment, the turret clamp holds and rotates workpieces at arbitrary points rather than being restricted to a specific point. This allows small workpieces to be clamped at their edges and rotated, rather than in the middle which would make it impossible to hold with both clamps. Large workpieces can be manipulated between the two clamps so that they never swing into the jaws. In other words, interior areas on large workpieces may be accessed from around the periphery by the cooperation of the edge clamp and rotating turret clamp. Moreover, the preferred embodiment comprises stationary and moveable tables on which the workpiece is supported. This holds the workpiece flat which increases the quality of the punched holes, and allows large or extremely thin pieces to be manipulated without drooping at the sides. Another advantage provided by the support tables is increased operator safety. As the workpiece is rotated, no sharp corners or appendages extend farther than the edge of the tables. This eliminates the frightening prospect of a workpiece slicing into a careless operator.

Brief Description of the Drawings Figure 1 is a right side view of an embodiment of a punch press incorporating the invention. Figure 2 is a top view of the punch press.

Figure 3 is a sectional view of the right side of the punch press, taken along the line 3-3 of Fig. 2.

SUBSTITUTE SHEET Figures 4a-h show the punch press of Figure 1 in various stages of operation.

Figure 5 shows a detail of punch and die turret assemblies of Figure l. Figure 6 shows a right side view of a preferred embodiment of a punch press.

Figures 7a-e show the punch press of Figure 6 in various stages of operation.

Figures 8a-b show alternative punch press frame configurations.

Detailed Description of the Drawings Referring now to the drawings, and in particular to Figs. 1 and 2, a punch press 10 is shown having an upper portion 11B and a lower portion 11C, defining a jaw J which is configured to permit movement therewithin of a workpiece W. The portions 11B and 11C rest on a base 11D. In the operation of the press 10, a computer (not shown) having appropriate software, provides programming capability for standard punching, nibbling functions for grids and circles, squares, rectangles and other shapes.

Compressed air and electrical lines enter the press 10 through a conduit 14A, into a control box 14 which connects by means of an air/electrical conduit 15A to the press 10.

The workpiece W is held in place by a workpiece edge clamp 40. An X-Y positioning carriage 9, driven by stepper motors (not shown) in the X and Y axes, moves the workpiece W in a precisely controlled manner, in sequence with die tool selection in a punch turret 67.

With reference now to Fig. 2, the workpiece W is shown having a number of openings punched therethrough, such as the openings 7A, 7B and 7C.

With reference to Fig. 3, there is shown a sectional view of the punch press 10. Depicted are: turret drive assembly C, punch turret assembly D, die turret assembly E, and turret locking assembly F.

The press 10 is electrically operated and utilizes compressed air to drive pneumatically operated components.

_SUBSTITUTE SHEET Therefore, specific details of electrical circuits and pneumatic lines are not shown, since such matters are readily understood by those skilled in the art.

In this regard, however, it will be noted that a pneumatic conduit 15, disposed within an air/electrical conduit 15A enters the press 10 through an opening 15C in a support plate 15D, located near the back of the press 10. The conduit 15 delivers pressurized air for operation, among other things, of a punch ram assembly 20. During operation of the ram assembly 20, a ram piston 35 forcibly drives a tool through a preselected part of the workpiece W to form an opening therein. A slug, not shown, produced by the punching operation, falls through a slug collecting tube 35A for collection and subsequent disposal. With regard now to the turret drive assembly C, a stepper motor 12 is fixed to a mounting block 13, which, in turn, is fixed to a cover 11A by conventional mounting means. Electricity is delivered to the motor 12 from a source not shown, through an electrical connection 16. A step motor shaft 17 connects the stepper motor 12 with a drive turret shaft pulley 18 which is fixed to the shaft 17 by a roll pin 19.

A toothed drive belt 24 connects the pulley 18 to a first punch turret drive shaft pulley 21. The first punch turret drive shaft pulley 21 is fixed to a turret drive shaft 22 by a roll pin 23. A second punch turret drive shaft pulley 25, fixed to the turret drive shaft 22 by means of a roll pin 26, is connected by a belt 33 to a main punch turret pulley 41. A turret drive shaft housing 27 separates the main punch turret pulley 21 from a die turret drive shaft pulley 31 which is connected by a belt 34 to a die turret pulley 43. The die turret drive shaft pulley 31 is fixed to the shaft 22 by means of a roll pin 32.

The inner, pulley contacting surfaces of the belts 24, 33 and 34 have regularly spaced teeth (not shown) for engagement with counterpart, similarly shaped teeth (not shown) on belt contacting surfaces of the respective pulleys, thereby providing for precise, controlled rotational movement of the pulleys. In addition, proper functioning of the press 10 requires that the movements and positioning of the pulleys 41 and 43 be precisely coordinated. In addition, further control is attained by belt conventional tensioning means such as the device 36 and a belt tensioner 38.

An additional mechanism is provided to ensure precise coordination of the operations of the pulleys 41 and 43 by means of a turret drive shaft hub 28 which is fixed to the shaft 22 by means of a roll pin 30. A turret phase alignment hub 29 is fixed to the pulley 31 and rotatably fixed about the shaft 22. The alignment hub 29 is adjustably fixable to the hub 28 by fixing means such as an alignment bolt 37 which rides in an annular opening (not shown) in the hub 28. The alignment bolt 37 may be loosened to permit relative rotational movement between the pulley 31 and the shaft 22, thereby allowing adjustment for precise phase alignment between the pulleys 41 and 43.

Referring now to the punch turret assembly D shown in Fig. 3 and, in more detail, Figure 5, a workpiece rotating clamp air cylinder 46 is fixed to a mounting block 44 which, in turn, is fixed to cover 11A by conventional means. An air cylinder extension shaft 47 extends between the cylinder 46 and a thrust coupling 48. A turret clamp shaft 50 is fixed to the lower end of thrust coupling 48 by means of roll pin 49. The turret clamp shaft 50 extends downward to turret clamp 75 which is fixed to shaft 50 by means of a roll pin 73. The air cylinder extension shaft 47, thrust coupling 48, turret clamp shaft 50 and turret clamp 75 are fixed relative to each other so that they translate in the vertical direction as one assembly. The air cylinder 46 thus actuates the clamping feature of the turret clamp 75.

A hollow punch turret shaft 51 is disposed around turret clamp shaft 50. Bearings (not shown) between turret clamp shaft 50 and punch turret shaft 51 provide for smooth relative vertical translation. The turret pulley 41 is rotatably fixed to turret clamp shaft 50 and punch turret shaft 51 via roll

_SUBSTITUTE SHEET pin 53. Roll pin 53 engages turret clamp shaft 50 through a vertical slot 55 which ensures vertical freedom of movement of shaft 50. The punch turret shaft 51 has a disk-shaped flange 74 on its lower end to which a punch turret 67 is fixed via means 76 and 77. The assembly is such that pulley 41, turret clamp shaft 50, punch turret shaft 51, turret clamp 75 and punch turret 67 are fixed to rotate as one unit'.

A stationary punch turret support block 57 is fixed to the housing 11A by conventional fixing means. Openings 59A, 59B and 59C in support block 57 permit passage and relative vertical and rotational movement therethrough of, respectively, the ram piston 35, punch turret shaft 50 and a turret locking pin 82.

A punch turret support plate 63 is mounted to support block 57 via fixing means 58. The punch support plate 63 is aligned by means of alignment pins 64 and 65. An opening 67A is provided in the punch support plate 63 to permit the passage therethrough of the punch turret shaft 51. From pulley 41, punch turret shaft 51 extends downward through hole 59B in punch turret support block 57, and aperture 67A in punch support plate 63. A bearing and oil cup arrangement (not shown) within holes 59B and 67A allow smooth rotation of punch turret shaft 50 in relation to the support block 57 and the punch support plate 63. Annularly disposed in the punch turret 67 is a plurality of punch turret lock pin inserts, such as the inserts 81 and 83. A row of die tools, spaced from each other at regular intervals, such as the tools 84 and 86, are disposed annularly near the periphery of the turret 67. During operation of the press 10, the turret 67 is rotated until a selected tool is positioned over the workpiece W for the punching function, then the turret locking pin 82 is driven into the turret lock pin insert 81 or 83.

Considering now the die turret assembly E in greater detail, with further reference to Fig. 3, a die turret block 88, fixed by conventional means to the housing 11A, has openings 91A, 91B and 91C, for passage therethrough,

SUBSTITUTE SHEET respectively of the slug collecting tube 35A, a bearing 93 and a support lock pin 94. Rotatably supported within the bearing 93 is a die turret shaft 95 integral with a material support plate 98 at its upper end. The die turret shaft 95 is connected by a roll pin 96 to the pulley 43. A die shoe support plate 99 is fixed to material support plate by fixing means 100. In this configuration, die turret pulley 43, die turret shaft 95, die shoe support plate 99 and material support plate 98 rotate as one assembly. Die shoes 101, configured to accept the die tools, such as the tools 84 and 86 are fixed around the periphery of the upper surface of support plate 99 by conventional means (not shown) . Dies 102 are fixed within the die shoes 101 by means such as common set screws (not shown) . Annularly disposed in the die shoe support plate 99 are lock pin inserts, such as the inserts 103 and 104, corresponding to the circumferential position of each die shoe 101.

The material support plate 98 projects slightly higher than the vertical height of die shoes 101 and dies 102. During operation of the punch 10, the plate 98 supports the workpiece W due to this slight difference in height. Further, upon activation of turret clamp 75, the workpiece W is held between the clamp 75 and support plate 98, and this combination rotates as one assembly due to the pulleys 41 and 43 being in phase alignment.

With regard now to the turret locking assembly F in greater detail, the assembly has compressed air delivered to cylinders 109A and 109B through fittings 112 and 118 respectively. On command, the cylinders 109A, 109B drive the locking pins 82 and 94 into locking pin inserts 83 and 104, respectively, . In this manner, the punch turret 67 and the support plate 98 are held stationary so that the tool 84 or 86 and die 102 underneath the ram 35 are rigidly aligned. Delivery of the compressed air to the cylinders 109A and 109B is accomplished simultaneously, with compressed air from a common source.

At this point in the punching operation, it will be noted

SUBSTITUTE SHEET that the portion of the workpiece W which is held by the edge clamp 40 is inaccessible to the punch turret 67. The stage is set for the rotation of the workpiece W. One example of workpiece W rotation is effected by the steps shown in Figs. 4a-4h which schematically depict the steps of workpiece centering, internal clamping and rotation. In the embodiment of Figures 4a-h, and in order to obtain precise workpiece positioning, it is important that rotation of the workpiece W be accomplished so that the position of the workpiece W centerpoint A, in relation to a turret centerpoint B, is always known (Figure 2) . More preferably, workpiece W rotation is effected by the steps shown in Figures 7a-e, and described later.

Fig. 4a shows the workpiece W held by the edge clamp 40. The carriage 9 moves the edge clamp 40 and workpiece W, providing X-Y positioning on computer command to align workpiece centerpoint A with turret centerpoint B. The turret locking pins 82, 94 are engaged with inserts 83 and 104, respectively, to lock the turrets in axial alignment. Fig. 4b depicts a system configuration similar to that shown in Fig. 4a except that the turret clamp 75 has been driven into contact with the workpiece W by turret clamp shaft 50, holding workpiece W securely against the material support plate 98. With the workpiece W thus clamped, Fig. 4c depicts the next step. Simultaneously, the punch turret lock pin 82 and the die turret lock pin 94 disengage. It will be noted that the workpiece W is still being held by the edge clamp 40. With regard to Fig. 4d, the step therein shown occurs virtually simultaneously with the step of Fig. 4c. In the step of Fig. 4d, the edge clamp 126 releases the workpiece W and the carriage 9 moves away from the workpiece W, along the Y axis. At this stage, the workpiece W is still being held between the turret clamp 75 and the material support plate 98 and the punch turret lock pin 82 and the die turret lock pin 54 are disengaged.

Fig. 4e shows the workpiece W with its centerpoint A aligned with the turret centerpoint B. The portion delineated

TITUTE SHEET by the bracket M represents that which had been held by the edge clamp 126 during the preceding punching operation. Fig. 4f depicts the condition wherein the workpiece W has been rotated 180 degrees, in the direction of the arrow P. This occurs when the stepper motor 12 (Fig. 3) has indexed the turret clamp 75 and the material support plate 98, to rotate both, together with the workpiece W, the desired 180 degrees. It will be noted that, after rotation, the bracketed portion M of the workpiece W is in position to be gripped by the edge clamp 40.

Fig. 4g shows the condition after workpiece W rotation has occurred. The edge clamp 126 has moved to its previous location along the Y axis, preparatory to gripping the workpiece W. It will be noted that the punch turret lock pin 82 and the die turret lock pin 94 are still disengaged and the workpiece W is still held by the turret clamp 75 against the material support plate 98.

In Fig. 4h, the workpiece W is released from the turret clamp 75, by turret clamp shaft 50, and the punch turret lock pins 82, 94 are reengaged. The edge clamp 126 regrips the workpiece W. At this stage, the workpiece W is free for movement along the X and Y axes, to be positioned for further punching operations.

Embodiment of Figures 6 and 7 A preferred embodiment and method of operation of the punch press is shown in Figures 6 and 7a-7e. The majority of features of the punch press 10 described above are identical in the preferred embodiment, with the addition of support tables 120a, 120b, 122, 124 and an improved workpiece edge clamp 126, replacing edge clamp 40, and containing dowel pins 128.

As seen from above in Figures 7a-7e, there are four coplanar support tables: a front 122, a rear 124 and two side tables 120a, 120b. The front 122 and rear 124 tables are mounted to the base 11D of the punch press 10. The carriage 9, driven by stepper motors (not shown) , translates in the Y- direction on a guide rod and threaded screw assembly, generally shown at 132 in Figure 6. The two side tables 120a, 120b are mounted to the carriage 9 assembly and thus translate in the Y-direction with the carriage 9. A workpiece W is held in place by the edge clamp 126 mounted to the carriage 9. The edge clamp 126 translates in the X-direction relative to the carriage 9 on a lead screw assembly, shown generally at 142, driven by stepper motors (not shown) .

The improved edge clamp 126 comprises an elongated clamp mouth 134 which pneumatic hoses, not shown, actuate to bring it closed with sufficient force to tightly grip the workpiece W. Vertical dowel pins 128 are spaced within holes 140 at regular intervals along the X-axis in the clamp mouth 134. These dowel pins 128 provide a stop for the initial insertion of the workpiece W. A reference edge R of the workpiece W is abutted against the dowel pins 128 for accurate alignment of the workpiece W, as more fully explained below.

Material translation balls 130 are rotatably held within bushing cups (not shown) in a regular pattern about the top surfaces of the support tables. The balls 130 project a sufficient distance above the plane of the support tables so that the workpiece W rests completely on them. The balls 130 act as bearings to facilitate sliding the workpiece W in the horizontal plane.

An improved method of workpiece W rotation is effected by the steps shown in Figs. 7a-7e, which schematically depict the steps of workpiece alignment and clamping, turret clamping, rotation and workpiece reclamping. In all these views, the workpiece W is drawn in phantom lines.

Figure 7a shows a workpiece W held in edge clamp 126 which is located at a home position. The workpiece W is split into four imaginary quadrants by two edge-to-edge lines drawn as centerlines. At the home position, the carriage 9 is at its far left travel limit with the edge clamp 126 centered laterally. The home position is adjustable in either a positive or negative direction in both axes. A reference edge R abuts a line of dowel pins 128 disposed within the mouth 134 of the edge clamp 126. This configuration more accurately

BSTITUTE SHEET aligns the reference edge R laterally than if a flat, continuous abutment was used. The minimal contact area between the reference edge R and the dowel pins 128 decreases the chance of misalignment occurring due to any localized imperfections in the reference edge R.

The edge clamp 126 and carriage 9 maneuver the workpiece W in the X-Y plane in a precisely controlled manner, in sequence with die tool selection in a punch turret 67. A computerized controller schematically indicated at 135 controls the operation. Advantageously, the control software of the punch press 10 provides for rapid movement of the workpiece W under the tool center 136 to punch the holes. The vector from the edge clamp 126, and by extension the reference edge R, to the tool center 136 is known, and thus it is an easy matter to calculate the X-Y translation necessary to position the dies over the proper places for punching. Punching of the workpiece W continues until there is no more available workpiece W to machine. In other words, the workpiece W must now be rotated before the portion proximate the edge clamp 126 can be machined.

A particular pattern is to be punched on the workpiece W using different die tools at a preset hole pattern. The punch press 10 utilizes special software to control the movement of the workpiece W and select the turret 67 position, which determines the die tool used. Movement of the workpiece W is from two sources: X-Y translation with the edge clamp 126 and carriage 9, and rotation with the turret clamp 75. Any workpiece W movement is thus dependent on the corresponding movements of these structures which are tracked with position sensors of various types built into the punch press 10. The control software utilizes the position feedback information to plot and instigate any subsequent workpiece W movements.

The general concept of keeping track of the workpiece W movements necessary before and after one or more rotations is described herewith. This description is given only as an example of the overall logic necessary to design the control software. Those skilled in the art of software design will

SUBSTITUTE SHEET recognize that this in no way limits the structure of the eventual code, and only lays out the preliminary design. Many other design routes might be alternatively taken.

Initially, the reference edge R is abutted with the dowel pins 128 and held rigidly in the edge clamp 126. The center of the line connecting the right side of the dowel pins 128 is considered (0,0) in the principle X-Y coordinate system when the edge clamp 126 and carriage 9 are at the home position. The tool center 136 is fixed relative to the home position and thus retains a ixed coordinate pair location in the principle X-Y system. A vector from the center of the reference edge R to the centerpoint of each hole in the punch pattern is known from operator inputs. As such, the control software is aware of the hole pattern to be punched with reference to the line of dowel pins 128 as well. Since the vector from the center of the line of dowel pins 128 to the fixed tool center 136 is known, this also means that the pattern on the workpiece W is known relative to the tool center 136, after a simple vector subtraction by the operating computer. The software then calculates a sequence of movements of the edge clamp 126 and workpiece W to position the proper hole centerpoints under the tool center 136, and effects punching of that portion available to the tool center 136. Advantageously, the side tables 120a, 120b travel longitudinally with the carriage 9 and none of the workpiece W extends beyond their perimeter. This affords a measure of operator safety as the extended moving portion is more blunt, and less likely to lacerate, than an exposed workpiece W edge. Before workpiece W rotation therefore, the only input parameters needed by the software are dimensions of the workpiece W and the hole locations and corresponding type of die tool needed. The operator ensures that the reference edge R is fully abutted against the dowel pins 128 and that the workpiece W is centered in the edge clamp 126. The software advantageously has built-in safeties to ensure that the edge clamp 126 never hits the turret 67, or alternatively that the workpiece W never contacts the rear support of the punch press j aws J .

After the final hole in that portion of the workpiece W available to the tool center 136 is punched, further punching requires a workpiece W rotation. Rotation of the workpiece W reorients the hole pattern to a different set of axes and thus the control software must adjust accordingly. One method of adjustment is detailed herewith.

As seen in Figure 7b, the workpiece W has been moved to position a particular point Q in quadrant S on its surface under the turret center 144 and concentric turret clamp 75, seen in Figure 5. At this point, the shaft 50 forces the turret clamp 75 down to grip the workpiece W, and edge clamp 126 releases the workpiece W. The location of point Q is arbitrary, with the requirement that rotation about point Q will allow previously unavailable workpiece W surface area to come within reach of the tool center 136. The control software uses a vector addition to calculate the vectors from the point Q to the hole pattern centerpolnts from the following known vectors: the hole centerpoint pattern relative to the reference edge, the current position of the reference edge R and thus the vector from the center of the reference edge to the fixed turret center 144.

After the turret clamp 75 has closed over the point Q, and material clamp 126 has released and retracted to the home position as in Figure 7c, the workpiece W may be rotated. Any angle of rotation may be programmed as long as a portion of workpiece W suitable for clamping is then presented to the edge clamp 126. The carriage 9 automatically homes itself when a workpiece W rotation is imminent. The turret clamp 75 grips the workpiece W, while the tables 120a, 120b, 122, 124 provide support.

In Figure 7d, the turret clamp 75 is in the process of rotating the workpiece W. The direction of rotation is shown with arrows 146. The advantageous feature of clamping and rotating from an arbitrary point is clearly shown. A corner or edge of the workpiece W would contact the rear 150 of jaw J if the workpiece were to be rotated about its center point,

_SU_BSTITUTE SHEET or in the opposite direction.

Figure 7d also illustrates the advantageous feature of the support tables 120a, 120b, 122, 124. Every portion of the workpiece W is supported upon the tables and no portion extends beyond their perimeter. This allows an operator to safely stand next to the punch press 10 during workpiece W rotation without fear of being hit by a corner. The side tables 120a, 120b provide the greatest protection in this respect and the width shown is only representative of one size. Larger sizes to accommodate larger workpieces may be installed.

Finally, in Figure 7e, the workpiece W has been rotated ninety degrees clockwise. The edge clamp 126 and carriage 9 have translated to a position wherein a maximum amount of workpiece W may be gripped. The edge clamp 126 is activated and the turret clamp 75 is released. At this point, previously unavailable quadrant T may be positioned under the tool center 136.

Previous to workpiece W rotation, vectors from the turret center 144 to the hole centerpoint pattern in the principle coordinate axes were known, as described above. Subsequent to workpiece W rotation, these vectors have the same magnitude and direction in a secondary coordinate system determined by the angle of rotation. Feedback from position sensors allows the control software to keep track of the angle of rotation of the turret clamp 75 and workpiece W. The operating computer then processes a transformation involving matrix operations to convert the coordinates of the vectors from the secondary to the principle coordinate system. Thus, new vectors from the turret center 144 to the reoriented hole centerpoint pattern in the principle coordinate system are known. The vector from the turret center 144 to the tool center 136 is fixed, and the operating computer performs a vector subtraction to obtain new vectors from the tool center 136 to the reoriented hole centerpoint pattern. The edge clamp 126 is brought into proximity of the nearest workpiece W edge and activated, while the turret clamp 75 is released allowing workpiece W translation. Further workpiece W translation, therefore, is a sequence of steps relocating the workpiece W under the tool center 136 based on their relative vectors, just calculated. Upon re-clamping, the workpiece W does not contact the dowel pins 128, to avoid possible misalignment from uneven workpiece W edges. Instead, the reference edge R initially establishes a workpiece W orientation with respect to the edge clamp 126 which fixes the orientation of the hole pattern. The rotation of Figures 7d, 7e changes the workpiece W orientation by ninety degrees according to the position sensors. A crooked edge abutted against the dowel pins 128 would disadvantageously alter the orientation of the workpiece W without knowledge of the punch press 10 control mechanism. Subsequent holes punched in the workpiece W would thus be misaligned with any previous holes. Thus, the edge clamp 126 grips the workpiece W without abutting the reference edge R and thus preserves the ninety degree orientation.

The above description of workpiece W translation, punching, rotation and automatic hole pattern reorientation is particularly suited to smaller workpieces as well. It may not be possible to clamp a smaller workpiece and extend it very far under the punch turret 67 to be machined. Thus, one or more rotations are necessary to finish punching the previously unavailable areas. Because of the small size, the workpiece thus has to be clamped by the turret clamp 75 close to one edge. Advantageously, this may be done automatically as many times as necessary without losing track of hole placement with the improved punch press 10 of the present invention.

Embodiment of Figure 8a Alternatively, punch presses embodying the novel concepts of the present invention may be mounted on other frame configurations. The punch press 10 shown in Figure 6 is a front-loading type. This refers to the edge clamp 126 presenting the workpiece W to the turret 67 from the front of the jaws J of the punch press 10. In the opposite configuration, shown in Figure 8a, an edge clamp 150 is disposed within the jaws J of a rear-loading punch press 148.

_SUBSTITUTE SHEET The edge clamp 150 grips a workpiece W to maneuver it under a turret 152 to be punched. All of the components associated with the clamping and punching functions of punch press 10, shown in Figure 5, are identical in punch press 148. Some elements have been relocated to accommodate the rear-loading configuration.

The rear-loading arrangement of punch press 148, in combination with the advantageous no waste feature of the present invention, allows even larger pieces to be punched. As seen in Figure 6, the limit to the maximum diagonal dimension of workpiece W that can be rotated within the punch press is the distance from the edge clamp 126 to the back of the jaws J. The rear-loading punch press 148 holds the workpiece W from within the jaws and extends the workpiece W out from the jaws J. Thus, the only limit on the workpiece W size is the area of support table 153.

Embodiment of Figure 8b A bridge type configuration is shown in Figure 8b. An edge clamp 160 is disposed within the mouth 162 of a punch press 166. The edge clamp 160 grips a workpiece W to maneuver it under a turret 170 to be punched. All of the components associated with the clamping and punching functions of punch press 10, shown in Figure 5, are identical in punch press 166. Some elements have been relocated to accommodate the bridge configuration.

It is not necessary for the bridge type punch press 166 to be built as sturdily as the front- or rear-loading configurations of Figure 6 and 8a. The added columnar strength associated with the enclosed frame provides an opportunity to reduce the mass and accompanying cost of the punch press 166. This design may not punch large pieces due to structural impediments, but the reduced size advantage gained by the bridge design makes the punch press 166 more affordable and thus admirably suited to more custom punching operations.

While the novel features of the present invention have been described and illustrated with reference to a preferred embodiment, the present invention is not limited thereto. On the contrary, alternatives, changes or modifications may become apparent to those skilled in the art upon reading the foregoing description. Accordingly, such alternatives, changes and modifications are to be considered as forming part of the invention insofar as they fall within the spirit and scope of the appended claims.

SUBSTITUTE SHEET

Claims

CLAIM:

1. A press for punching material comprising: a die tool turret having at least one die; means for rotating said turret to position a die in relation to the material to be punched; die tool driving means for driving said die through said material; means for supporting the material during the punching operation; material clamping means for releasably holding said material against said supporting means; and means for rotating simultaneously said clamping means and said supporting means while said material is held thereagainst.

2. A press of Claim 1, including means for locking said turret to prevent rotational movement thereof while said clamping means and said rotating means are being rotated.

3. A press of Claim 1, including die shoe means for receiving a die shoe during the punching operation.

4. A press of Claim 1, including means for supporting said die shoe means.

5. A press of Claim 1, including means for rotating said supporting means during the punching operation.

6. A press of Claim 1, including means for controlling the rotation of said turret means and of said supporting means so that said turret means and said supporting means rotate simultaneously in the same direction and for substantially the same amount of rotation.

7. A press of Claim 6, wherein said controlling means includes a step motor and a plurality of pulleys.

8. A press of Claim 7, wherein one of said pulleys drives said turret for rotational movement.

9. A press of Claim 7, wherein one of said pulleys drives said supporting means for rotational movement.

10. The press of Claim 1, including an edge clamp for gripping an edge of said workpiece, a fixed table for supporting the workpiece extending between the edge clamp and the turret clamp, said edge clamp being movable relative to said table toward and away from said turret.

11. The press of Claim 10, including a pair of side tables for supporting said workpiece, one on each side of said fixed table, said side tables being movable with said edge clamp when said edge clamp is moved forward and away from said turret clamp.

12. The press of Claim 10, including a plurality of dowel pins positioned within said edge clamp to be engaged by an edge of said workpiece and form a reference line for the punching of holes in said workpiece.

13. The press of Claim 12, including a control unit which utilizes the location of said reference line to determine the location of openings to be punched in said workpiece after the workpiece has been rotated from a first position clamped by said edge clamp wherein the workpiece engages said dowels, to a second position wherein said edge clamp grips said workpiece without an edge of the workpiece engaging said dowels.

14. A press for punching material, comprising: a die for cutting said material; means for punching said die through said material; an edge clamp for releasably gripping a first edge of the material during the punching operation; means for translating said clamp and said material transversely to enable a plurality of holes to be formed in the material; a second clamp for releasably gripping said material at a location other than said first edge; and means for rotating simultaneously said second clamp and said material to a position where a second edge of said material may be gripped by said edge clamp so that said first edge of the material may be moved to a position beneath said die.

15. The press of Claim 14, including means associated with said edge clamp defining a reference line to engage a reference edge of said material.

16. The press of Claim 15, wherein said reference line is formed by spaced dowels.

17. The press of Claim 14, including support tables for said material that are connected to move with said edge clamp toward and away from said die.

18. A method of punching holes comprising: clamping a workpiece to be punched, in" relation to a die turret, with rotatable turret clamping means; supporting said workpiece while said workpiece is held in said clamping means; punching a hole in said workpiece with said die turret; locking said turret to prevent rotation thereof; and rotating simultaneously said clamping means and said supporting means to rotate said material.

19. The method of Claim 18, including clamping an edge of said workpiece while said punching is occurring.

20. The method of Claim 18, including clamping an edge of said workpiece with an edge clamp, moving said edge clamp and said workpiece transversely with respect to said turret, and punching a plurality of holes in said workpiece.

21. The method of Claim 20, including: releasing said edge clamp; clamping said workpiece with said turret clamping means; rotating said workpiece; clamping a second edge of said workpiece with said edge clamp; and moving said edge clamp and said workpiece to a position where the edge of said workpiece initially gripped by said edge clamp is beneath said turret die.

22. A method of punching openings in a thin flap workpiece comprising: positioning the workpiece on a support beneath a puncher; gripping one edge of the workpiece with an edge clamp; punching one or more holes in the workpiece at desired locations with said punch press; clamping the workpiece with a second clamp; releasing the grip on said one edge of the workpiece; rotating said second clamp together with the clamped workpiece; gripping a second edge of said workpiece with said edge clamp; unclamping said second clamp; and moving said edge clamp and said workpiece into position whereby openings can be punched in said first edge by said puncher.

23. The method of Claim 22, including the step of positioning one edge of said workpiece against a reference line in said edge clamp when said workpiece is gripped in its first edge position.

24. The method of Claim 23, wherein said second edge is not placed against said reference line when gripped by said edge clamp.

25. The method of Claim 23, wherein said reference line is established by a series of spaced dowels positioned in said edge clamp.

26. The method of Claim 22, including the step of supporting said workpiece with a fixed central table and with a pair of side tables movable with said edge guide when said edge guide is moved toward and away from said puncher.

27. The method of Claim 22, wherein the clamping by said second clamp may at most any location on said workpiece other than the workpiece edge being gripped by said edge clamp.

28. The method of Claim 22, wherein said workpiece is generally rectangular and said clamping by said second clamp occurs in one corner quadrant of the workpiece, and said rotating rotates said workpiece 90°.

29. The method of Claim 22, wherein said workpiece is rotated 180° during said rotating step.

SUBSTITUTE SHEET