US3845654A

US3845654A - Die forming apparatus

Info

Publication number: US3845654A
Application number: US00379402A
Authority: US
Inventors: F Fuller; S Melvin; P Merritt
Original assignee: Caterpillar Tractor Co
Current assignee: Caterpillar Inc
Priority date: 1973-07-13
Filing date: 1973-07-13
Publication date: 1974-11-05
Anticipated expiration: 1991-11-05
Also published as: BE816251A; JPS5038872A; GB1424979A

Abstract

A die forming apparatus for forming a workpiece of substantially flat sheet material into a corrugated configuration including a pair of opposing dies one of which has a plurality of die members that are powerably moved individually successively toward the other die so that the workpiece is positively and fully formed in each area of engagement by each of the die members progressively from one end of the workpiece to the other unformed end to permit substantially unrestrained gathering of the workpiece from the unformed end.

Description

llnited States Patent [1 1 Fuller et a1.

[ DIE FORMING APPARATUS [75] Inventors: Francis W. Fuller, Peoria; Samuel L.

Melvin, Morton; Paul H. Merritt, East Peoria, all of 111. [73] Assignee: Caterpillar Tractor Co., Peoria, 111.

[22] Filed: July 13, 1973 [21] Appl. No.: 379,402

[52] 11.8. CI 72/381, 72/385, 72/403, 113/1 G [51] lnt. C1 321d 5/02 [58] Field of Search 72/381, 385, 403, 452; 113/1 G, 116 Y [56] References Cited UNITED STATES PATENTS 24,689 7/1859 Worthen et al 72/403 1,939,065 12/1933 113/1 G 2,378,742 6/1945 72/381 2,397,582 4/1946 72/403 2,510,024 5/1950 72/397 2,960,141 11/1960' 72/62 3,307,387 3/1967 Lacey et a1. 72/385 [451 Nov. 5, 1974 3,340,719 9/1967 Kandle ct a1 72/385 3,439,521 4/1969 Tetart 72/403 3,748,889 7/1973 Miller et' a1. 72/385 FOREIGN PATENTS OR APPLICATIONS 454,229 9/1936 Great Britain Primary Examiner C. W. Lanham Assistant Examiner.lames R. Duzan Attorney, Agent, or Firm-Ralph E. Walters 57 ABSTRACT A die forming apparatus for forming aworkpiece of substantially flat sheet material into a corrugated configuration including ,a pair of opposing dies one of which has a plurality of die members that are powerably moved individually successively toward the other die so that the workpiece is positively and fully formed in each area of engagement by eachof the die members progressively from one end of the workpiece to the other unformed end to permit substantially unrestrained gathering of the workpiece from the unformed end.

18 Claims, 6 Drawing Figures BACKGROUND OF THE INVENTION Prior attempts to overcome the problem of stretching and tearing relatively thin sheet material while being formed into a corrugated configuration between a pair of movable dies have included utilizing segmented dies in order to reduce the area of the sheet that is being formed at a particular time. Heretofore, the die segments of such mechanisms have been arranged with the center segment extending below the adjacent segments with the remaining segments arranged in stairstep fashion laterally outwardly therefrom. When the center segment initially contacts the sheet material and forms the center groove therein, the other segments are spaced above the sheet material and do not provide any appreciable control of the deflection of the unformed portion of the sheet material.

A typical example of such arrangements is taught by the US. Pat. No. 2,954,068. Although the die segments thereof individually engage and fully form the grooves sequentially, such forming occurs only in conjunction with and as a result of movement of the platen on which the die segments are supported. Each die segment is individually connected to their supporting platen through a hydraulic cylinder of a hydraulic cushioning system which maintains the hydraulic fluid in the cylinder until the groove is fully formed. At that time, the fluid is expelled through a relief valve. Subsequently, a control valve opens to direct the fluid to the tank in response to the platen reaching a predetermined position and remains opened during the remaining downward movement of the platen. Since each cylinder or corresponding pair of cylinders requires a separate relief valve and control valve, the hydraulic system is extremely complicated necessitating intricate sequencing of the control valves for proper operation. Also, since each die segment is connected to its supporting platen through a separate cylinder, the minimum size of each groove that can be formed, without having a plurality of relatively small groove forming ridges on each die segment, is limited by the size of the cylinder. Thus, it is virtually impossible to form a corrugated sheet having relatively narrow individually formable grooves with such arrangement.

Other examples of such mechanisms are taught by the constructions disclosed in US. patent application Ser. No. 202,948 filed on Nov. 29, 1971 by Miller et al.

and assigned to the assignee of the present application; in US. Pat. No. 2,5l0,024; and in British Pat. No. 454,229.

OBJECTS OF THE INVENTION Accordingly, an object of this invention is to provide an improved die forming apparatus for forming a workpiece of substantially flat sheet material into a predetermined relatively narrowly grooved corrugated configuration.

Another object of this invention is to provide such a die forming apparatus which will permit substantially unrestrained gathering of the sheet material during the formation thereof to virtually eliminate any stretching and possible tearing of the material.

Another object of this invention is to provide an improved die forming apparatus of the character described with which the grooves of a corrugated sheet LII are individually and progressively formed from one end of the sheet to the other while limiting uncontrolled deflection of the unformed portion of the sheet by utilizing a plurality of individually power actuated die members which are initially positionable in relatively lightly material engaging relation prior to forming the grooves without any appreciable stretching of the sheet material.

Other objects and advantages of the present invention will become more readily apparent upon reference to the accompanying drawings and following description.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a die forming apparatus embodying the principles of the present invention associated with a die forming machine.

FIG. 2 is a sectional view through the die forming apparatus taken generally along the line Il-Il of FIG. 1 illustrating an open position for receiving a workpiece of substantially flat sheet material.

FIG. 3 is a schematic illustration of the hydraulic and electrical circuits for operating the die forming apparatus.

FIG. 4 is a somewhat enlarged sectional view taken generally along the line lV-IV of FIG. 2 of the die forming apparatus showing a plurality of die members in a workpiece forming position.

FIG. 5 is an enlarged fragmentary sectional view of the die members of FIG. 4.

FIG. 6 is a vertical sectional view through the die members taken generally along the line VIVl of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to the drawings, a die forming apparatus embodying the principles of the present invention is generally indicated at 10 mounted on a die forming machine 11 having a front face 12. The die forming machine includes a base 13, a pair of spaced vertical supports 14 extending upwardly therefrom, and an upper member 16 secured to the upper end of the supports. A vertically disposed hydraulic jack 17 is mounted to the upper member and has a downwardly directed rod 18 extending below the upper member. A hydraulic system 19 employed for actuation of the hydraulic jack includes a sump 21 disposed adjacent to the rear of the die forming machine.

A substantially rectangular lower platen 22 is suitably secured to the base 13. A pair of guide pins 23 extend upwardly from the lower platen and are individually disposed in the corners adjacent to the front face 12. A rectangular upper platen 24 is secured to the distal end of the rod 18 of the hydraulic jack 17 and is disposed for vertical movement toward and away from the lower platen in the usual manner. A pair of bores 25 extend through the upper platen and are adapted to receive the guide pins to align the upper and lower platens. A stop block 26 is fastened to the lower platen sub stantially between the guide pins. A plurality of adjustment shims 27 are removably disposed between the stop block and lower platen and cooperate with the stop block for adjustably limiting the downward movement of the upper platen.

The die forming apparatus 10 of the present invention includes a lower substantially planar die member 28 presenting a substantially unitary profile secured to the lower platen 22. As more clearly shown in FIGS. 4 and 5, an upper surface 29 of the die member has a plurality of spaced parallel grooves 31 formed therein with the grooves being disposed substantially parallel to the front face 12 of the machine 11. A pair of locator blocks 32, as shown in FIG. 2, are secured in laterally spaced relation to a rear surface 33 of the die member.

As shown in FIGS. 1, 2 and 4, an upper die assembly 34 having a segmented profile is secured to the upper platen 24 and includes a pair of spaced parallel U- shaped supports 36 disposed substantially parallel to the front face 12 of the machine 11. Each support has a pair of legs 37 projecting individually upwardly from the outer ends of a crossbar 38 and is secured to the upper platen by a pair of bolts 39. Each crossbar has a pair of horizontally disposed and spaced bores 41 extending therethrough normal to the front face with the bores of the one crossbar individually aligned with the respective bores of the other crossbar.

As more clearly shown in FIGS. 4, and 6, a pair of elongated end die members 42 and 43 and a plurality of intermediate die members 44 are disposed in a stacked side-to-side self guiding relation between the crossbars 38 with each die member being individually slidable toward and away from the upper platen 24. The end die member 42 has a full length projection 46 formed on its bottom surface substantially intermediate its sides. Each of the intermediate die members 44 has a similar projection 47 disposed adjacent to the rearward side while the end die member 43 has a pair of spaced projections 48 individually adjacent to the opposite sides thereof. The projections 46, 47 and 48 are individually aligned with the grooves 31 of the planar die member 28. A beveled ramp 49 is formed on the upper rear edge of each of the die members. Each die member has a pair of apertures 50 extending therethrough individually aligned with the bores 41 of the crossbars. A pair of elongated rods 51, the diameter of which is slightly smaller than the apertures, individually extend loosely through the apertures and have their ends secured within the respective bores 41 of the U- shaped supports 36. A pair of guide blocks 52 are individually disposed at the ends of the die members between the U-shaped supports and are secured to the upper platen by a plurality of bolts 53.

As more clearly shown in FIGS. 2 and 6, a pair of spaced elongated plates 54 are secured to the bottom surface of the upper platen 24 between the legs 37 of the U-shaped supports 36 forming a slot 55 between the plates and an elongated passage 56 between the plates and the crossbars 38 of the supports. The slot and passage are disposed substantially normal to the front face 12.

An actuating slide bar 57 is slidably disposed within the passage 56 and has an upwardly extending guide 58 slidable within the slot 55. A nose portion 59 is disposed at the forward end of the slide bar and has a beveled cam surface 61 provided across the full width thereof.

A hydraulic jack 62 having an extendible-retractable rod 63 is horizontally mounted on a bracket 64. The bracket is secured to the rear edge of the upper platen 24 and has a horizontally disposed bore 66 through which the rod extends. A groove 67 is formed in the lower surface of the upper platen substantially parallel to the rod to provide sufficient clearance for the rod as it is extended and retracted. The distal end of the rod is screw threadably secured to the actuating slide bar 57 so that actuation of the jack causes the slide bar to be reciprocated through the passage 56.

As more clearly shown in FIG. 3, the hydraulic system 19 includes a pump 68 which is driven by a motor 69 disposed adjacent to the sump 21 as shown in FIG. 1. The pump draws fluid from the sump and delivers such fluid through a conduit 70 to a control valve 71. The control valve has a pair of

solenoids

72 and 73 individually disposed on its end for selectively shifting the control valve. The control valve is spring returned to its neutral position when the solenoids are deactivated. A pair of

conduits

74 and 76 connect the control valve to the head end and rod end, respectively, of the hydraulic jack 17. A conduit 77 connects the rod end of the hydraulic jack 62 with the conduit 76. A conduit 78 having a check valve 79 interposed therein connects the head end of the hydraulic jack 62 with the conduit 74. The check valve permits unrestricted fluid flow from the hydraulic jack 62 to the conduit 74 while blocking reverse flow therethrough. A bypass conduit 81 having a sequence valve 82 interposed therein is interconnected to the conduit 78 on opposite sides of the check valve. A relief valve 83 communicates between the conduit 70 and the sump to relieve excess pressure in the hydraulic system.

The

solenoids

72 and 73 of the control valve 71 are actuated by an electrical circuit 84 which includes a source of power 86 connected to a manually actuatable switch 87. The switch has a pair of

output terminals

88 and 89 with terminal 88 being connected to the solenoid 72 through a lead line 91. The terminal 89 is connected to the solenoid 73 through a lead line 92 which has a switch 93 interposed therein. The switch 93 is normally closed and is mechanically actuated to the open position when the rod 18 of the hydraulic jack 17 is retracted to a predetermined position.

OPERATION While the operation of the present invention is believed clearly apparent from the foregoing description, further amplification will subsequently be made in the following brief summary of such operation. The forming cycle commences with the upper platen 24 and die assembly 34 elevated above the lower platen 22 and planar die member 28 as shown in FIGS. 1 and 2. With the die assembly elevated, the

die members

42, 43 and 44 are supported by the rods 51.

A workpiece 94 of substantially flat sheet material is positioned on the planar die member 28 with its rear edge in abutment with the locator blocks 32. The switch 87 is manually actuated to connect the source of power 86 with the terminal 88 for activating the solenoid 72 which shifts the control valve 71 to the right. This directs hydraulic fluid from the pump 68 to the head end of the hydraulic jack 17 causing the rod 18 to extend thereby lowering the upper platen 24. The check valve 79 and sequence valve 82 are effective in blocking fluid flow through the

conduits

78 and 81 to the hydraulic jack 62.

As the upper platen 24 approaches the stop block 26, the

die members

42, 43 and 44 contact and are supported by the workpiece while the remaining components of the die assembly 34 continue to move downwardly until the upper platen contacts the stop block establishing a preforming position. Thereafter the pressure in the hydraulic jack 17 increases sufficiently to open the sequence valve 82 permitting hydraulic fluid to be transmitted to the head end of the hydraulic jack 62 causing its rod 63 to extend therefrom.

Extension of the rod 63 causes the actuating slide bar 57 to be translated through the passage 56. In so doing, the beveled cam surface 61 of the cam first engages the beveled ramp 49 of the end die member 42 forcing it downwardly toward the planar die member 28. The projection 46 of the die member positively forces the workpiece into the matching groove 31 such that a groove is fully and permanently formed in the workpiece as shown in FIGS. 4 and 5. As the slide bar progresses through the passage, the beveled cam surface of the slide bar successively engages the beveled ramp of the intermediate die members 44 and end die member 43 individually successively forcing them toward the planar die member.

As the

die members

42, 43 and 44 are actuated they are effective to positively and fully form each of the grooves in the workpiece progressively from the end adjacent to the locator block to the opposite end thereof aseach engagement by the die members occurs. The unactuated die members ahead of the slide bar 57 remain in lightly constraining engagement with the workpiece for limiting uncontrolled deflection in the unformed portion of the workpiece and maintain it in a substantially flat condition. The unformed material is permitted readily to slide between the planar die member 28 and the movable die members freely allowing the sheet material to gather substantially unrestrained from the free end as the grooves are individually formed thus effectively minimizing stretching and- /or tearing of the thin sheet material. Such gathering of the material allows forming of grooves of greater depth; i.e., greater aspect ratio than heretofore possible and also permits forming of extremely thin sheet material having a thickness on the order of 0.002 or 0.003 inches.

The distance between the upper platen 24 and the lower platen 22 in the preforming position in combination with the rise of the camming surface 61 of the slide bar 57 determines the depth of the corrugations formed in the workpiece 94 by establishing the depth to which the projections 46, 47 and 48 of the

die members

42, 44 and 43, respectively, extend into the grooves 31 of the planar die member 28. The preforming position is adjustable over a predetermined range by adding or removing o'ne or more of the shims 27 between the stop block 26 and the lower platen. For example, removing all the shims would permit the projections to extend into the grooves a greater distance forcing the workpiece farther into the grooves thereby forming deeper grooves in the workpiece. Conversely, adding more or thicker shims would result in the forming of shallower grooves in the workpiece. Thus, the same combination of planar die member and upper die assembly may be employed for progressively fully forming grooves or corrugations of different depths within a predetermined range.

After the workpiece has been formed into a grooved, corrugated shape, the switch 87 is manually actuated to disconnect the power source 86 from the solenoid 72. This also connects the power source to the terminal 89 and to the solenoid 73 through the normally closed switch 93. Activating solenoid 73 shifts the control valve to the left simultaneously to direct fluid to the rodends of the

hydraulic jacks

17 and 62. However, since the hydraulic jack 17 must lift the relatively heavy upper platen 24 and die assembly 34, the rod 63 of the hydraulic jack 62 retracts first to return the slide bar 57 to its initial position such that it is not in engagement with any of the

die members

42, 43 or 44. The pressure in the hydraulic system then increases sufficiently to cause the rod 18 of the hydraulic jack 17 to retract and thereby raise the upper platen and die assembly.

When the upper platen 24 reaches a predetermined elevated position, the switch 93 is mechanically actuated to its open position allowing the control valve 71 to be spring returned to its neutral position. This blocks fluid flow from both

conduits

74 and 76 and thereby holds the hydraulic jack 17 in its retracted position while permitting the pump flow to be returned directly to the sump 2 1. The finished workpiece is then removed from the planar die member and the next forming cycle initiated.

In view of the foregoing, it is readily apparent that the structure of the present invention provides a die forming apparatus for individually forming grooves in a workpiece of sheet material progressively from one end thereof to the other while permitting substantially unrestrained gathering of the material from its free unformed end. Thus, stretching and/or tearing of the relatively thin sheet material of the workpiece is effectively minimized and each groove is positively and fully formed prior to the forming of the next groove. The unrestrained gathering of the material allows the forming of grooves of greater aspect ratio than was heretofore possible particularly with extremely thin sheet material. The weight of the die members resting on the unformed portion of the workpiece is sufficient to control the deflection of the unformed portion while permitting the material to slide therebeneath as it is gathered during forming of the grooves.

While the invention has been described and shown with particular reference to the preferred embodiment, it will be apparent that variations might be possible that would fall within the scope of the present invention which is not intended to be limited except as defined in the following claims.

What is claimed is:

l. A die forming apparatus for forming a multiplicity of corrugations in a workpiece of substantially flat sheet material, comprising;

a stationary die;

a movable die disposed in opposing relation to said stationary die and movable toward and away from said stationary die between a workpiece loading and unloading position and a forming position, said movable die having a plurality of die members disposed for individual movement toward said stationary die when said movable die is in said forming position and for unitary movement to said loading and unloading position; and

powered means operatively associated with said movable die for powerably moving said die members individually sucessively toward said other die so that each of such corrugations is positively and fully formed in each area of engagement by each of said die members progressively from one end of the workpiece to the other unformed end to permit substantially unrestrained gathering of the workpiece from the unformed end with all of the corrugations formed in the workpiece in a single cycle of said powered means.

2. The die forming apparatus of claim 1 wherein said powered means includes cam means being operative to individually successively engage and move the plurality of die members toward said stationary die.

3. The die forming apparatus of claim 2 wherein said cam means is an actuating slide bar having a nose portion formed thereon with the slide bar being disposed for movement in a direction substantially normal to the direction of movement of said die members, said slide bar including a beveled cam surface formed on said nose portion thereof, and a beveled ramp formed on each of said die members disposed in the path of movement of said slide bar for engagement by said beveled cam surface.

4. The die forming apparatus of claim 3 including frame means slidably mounting said plurality of die members and having an elongated passage through which said actuating slide bar is slidably received and into which said beveled ramps of the die members are extended.

5. The die forming apparatus of claim 4 wherein each of said die members has a bore extending therethrough, and an elongated rod mounted in said frame means extending through said bores of said die members, said rod being slightly smaller than said bores to permit limited movement of the die members relative to the frame means.

6. The die forming apparatus of claim 5 wherein said die members are disposed in intimately slidable contacting side-by-side self-guiding relation.

7. The die forming apparatus of claim 6 wherein said stationary die defines a plurality of spaced parallel grooves and wherein each of said die members has a projection formed thereon adapted to mesh with a respective one of said grooves.

8. The die forming apparatus of claim 7 including means for positioning said movable die so that said die members are in relatively lightly workpiece engaging position prior to forming the workpiece for limiting uncontrolled deflection of the unformed end of the workpiece as the workpiece is being formed.

9. A die forming apparatus adapted for use on a die forming machine to form a workpiece of substantially flat sheet material into a relatively narrowly grooved corrugated configuration with the machine having a pair of platens arranged for relative movement toward and away from each other between a workpiece loading and unloading position and a forming position, comprising;

a unitary profile die rigidly mounted on one of such platens;

a segmented profile die having a plurality of die members individually slidably mounted on the other of such platens for extendible meshing engagement with said unitary profile die when said platens are in said forming position, said segmented profile die and said other platen defining an elongated passage oriented substantially normal to the direction of movement of the die members; and

an actuating slide bar disposed for powered rectilinear movement through said elongated passage for individually successively actuating said plurality of 6 die members toward said unitary profile die to fully form a workpiece disposed therebetween progressively toward its unformed end in each area of engagement by each of said die members to permit substantially unrestrained gathering of the workpiece from said unformed end with all of the corrugations formed in the workpiece with a single stroke of the actuating slide bar.

10. The die forming apparatus of claim 9 including motor means attached to said actuating slide bar for power actuating the slide bar through said passage, said actuating slide bar having a camming surface formed thereon, each of said die members having a beveled ramp formed thereon and extendible into said passage for engagement for said cam surface as said actuating slide bar is moved through said passage.

11. The die forming apparatus of claim 10 wherein each of said die members has a bore extending therethrough and wherein said segmented profile die includes frame means having an elongated rod extending through said bores of said die members, said rod being slightly smaller than said bores to permit limited movement of the die members relative to the frame means.

12. The die forming apparatus of claim 11 wherein said unitary profile die defines a plurality of spaced parallel grooves and wherein each of the die members has a projection formed thereon adapted to mesh with a respective one of said grooves.

13. The die forming apparatus of claim 12 wherein the die members are disposed in parallel stack side-byside self-guiding relation.

14. The die forming apparatus of claim 13 including motor means operatively attached to said other platen for moving it vertically toward and away from said one platen between said workpiece loading and unloading position and said forming position and stop means for stopping movement of said platens toward each other in said forming position whereby said die members are positioned in a relatively lightly material engaging position for limiting the uncontrolled deflection of the unformed portion of the workpiece as the workpiece is being formed.

15. The die forming apparatus of claim 14 including means operatively associated with said die members for adjusting the depth to which said projections of said die members are permitted to extend into said grooves of said unitary die so that said die members and said unitary die are adapted for progressively fully forming grooves of different depths within a predetermined range.

16. The die forming apparatus of claim 15 including a stop block fastened to said one platen, and a plurality of shims removably disposable between said stop block and said one platen.

17. A method of forming a workpiece of substantially flat sheet material into a corrugated configuration with a die forming machine having a pair of platens arranged for relative movement toward and away from each other, comprising the steps of;

inserting the workpiece between a unitary profile die rigidly mounted on one of such platens and a segmented profile die having a plurality of die members individually slidably mounted on the other of such platens for extendible meshing engagement with said unitary profile die;

moving the platens and dies to a preforming position with all of the die members in relatively lightly engaging relation with the workpiece;

moving a slide bar having a cam surface in a rectilinear path; and

individually successively engaging said plurality of die members with said cam surface of the slide bar to move them toward said unitary profile die to fully form the workpiece progressively toward one end thereof in each area of engagement by each of said die members to permit substantially unrestrained gathering-of the workpiece.

18. A die forming apparatus for forming a multiplicity of relatively narrow grooves in a workpiece of substantially flat sheet material comprising;

a lower stationary platen;

an upper movable platen disposed in opposing relation vertically above said stationary platen;

motor means attached to said movable platen for moving it towards and away from said stationary platen between a workpiece loading and unloading position and a forming position;

a unitary profile die mounted on said stationary platen having a plurality of parallel grooves formed therein; 1

a segmented profile die mounted on said movable platen having a plurality of die members individually movable toward said unitary profile die individually to mesh with said grooves when said movable platen is in said forming position and movable away from said unitary die in unison when said movable platen is moved to said workpiece loading and unloading position;

means forming an elongated passage between said movable platen and said plurality of segmented dies substantially normal to the direction of movement of said die members; and w an actuating slide bar disposed for powered rectilinear movement through said passage for sequentially engaging and moving said die members individually successively into said grooves of said unitary profile die to fully form each of such grooves in the workpiece prior to the forming of the following adjacent groove to permit substantially unrestrained gathering of the workpiece from the unfonned end with all of the grooves formed in the workpiece in a single rectilinear stroke of the actuating slide bar.

Claims

1. A die forming apparatus for forming a multiplicity of corrugations in a workpiece of substantially flat sheet material, comprising; a stationary die; a movable die disposed in opposing relation to said stationary die and movable toward and away from said stationary die between a workpiece loading and unloading position and a forming position, said movable die having a plurality of die members disposed for individual movement toward said stationary die when said movable die is in said forming position and for unitary movement to said loading and unloading position; and powered means operatively associated with said movable die for powerably moving said die members individually sucessively toward said other die so that each of such corrugations is positively and fully formed in each area of engagement by each of said die members progressively from one end of the workpiece to the other unformed end to permit substantially unrestrained gathering of the workpiece from the unformed end with all of the corrugations formed in the workpiece in a single cycle of said powered means.

9. A die forming apparatus adapted for use on a die forming machine to form a workpiece of substantially flat sheet material into a relatively narrowly grooved corrugated configuration with the machine having a pair of platens arranged for relative movement toward and away from each other between a workpiece loading and unloading position and a forming position, comprising; a unitary profile die rigidly mounted on one of such platens; a segmented profile die havinG a plurality of die members individually slidably mounted on the other of such platens for extendible meshing engagement with said unitary profile die when said platens are in said forming position, said segmented profile die and said other platen defining an elongated passage oriented substantially normal to the direction of movement of the die members; and an actuating slide bar disposed for powered rectilinear movement through said elongated passage for individually successively actuating said plurality of die members toward said unitary profile die to fully form a workpiece disposed therebetween progressively toward its unformed end in each area of engagement by each of said die members to permit substantially unrestrained gathering of the workpiece from said unformed end with all of the corrugations formed in the workpiece with a single stroke of the actuating slide bar.

13. The die forming apparatus of claim 12 wherein the die members are disposed in parallel stack side-by-side self-guiding relation.

17. A method of forming a workpiece of substantially flat sheet material into a corrugated configuration with a die forming machine having a pair of platens arranged for relative movement toward and away from each other, comprising the steps of; inserting the workpiece between a unitary profile die rigidly mounted on one of such platens and a segmented profile die having a plurality of die members individually slidably mounted on the other of such platens for extendible meshing engagement with said unitary profile die; moving the platens and dies to a preforming position with all of the die members in relatively lightly engaging relation with the workpiece; moving a slide bar having a cam surface in a rectilinear path; and individually successively engaging said plurality of die members with said cam surface of the slide baR to move them toward said unitary profile die to fully form the workpiece progressively toward one end thereof in each area of engagement by each of said die members to permit substantially unrestrained gathering of the workpiece.

18. A die forming apparatus for forming a multiplicity of relatively narrow grooves in a workpiece of substantially flat sheet material comprising; a lower stationary platen; an upper movable platen disposed in opposing relation vertically above said stationary platen; motor means attached to said movable platen for moving it towards and away from said stationary platen between a workpiece loading and unloading position and a forming position; a unitary profile die mounted on said stationary platen having a plurality of parallel grooves formed therein; a segmented profile die mounted on said movable platen having a plurality of die members individually movable toward said unitary profile die individually to mesh with said grooves when said movable platen is in said forming position and movable away from said unitary die in unison when said movable platen is moved to said workpiece loading and unloading position; means forming an elongated passage between said movable platen and said plurality of segmented dies substantially normal to the direction of movement of said die members; and an actuating slide bar disposed for powered rectilinear movement through said passage for sequentially engaging and moving said die members individually successively into said grooves of said unitary profile die to fully form each of such grooves in the workpiece prior to the forming of the following adjacent groove to permit substantially unrestrained gathering of the workpiece from the unformed end with all of the grooves formed in the workpiece in a single rectilinear stroke of the actuating slide bar.