US 3760624 A
Disclosed is a device for continuously forming a metal sheet into sinuous or corrugated configuration by using two opposed, metal-engaging dies, each movable toward and away from the other in a vertical forming stroke, and one of the dies also being movable in a limited stroke transverse to its vertical forming stroke. Slides, moving horizontally in reciprocating fashion, have inclined surfaces which cause the vertical motion of the dies. A latching and latch-releasing means, actuated by the slides during the terminal increment of their horizontal motion at each end of their stroke, provide the horizontal die stroke only when the dies have completed their vertical stroke.
Description (OCR text may contain errors)
United States Patent 1 Robinson 1 51 Sept. 25, 1973 SELF FEEDING CONTINUOUS FORMING DEVICE  Inventor: James J. Robinson, 5305 Bevedere Related U.S. Application Data  Continuation-impart of Ser. No. 111,375, Feb. 1,
FOREIGN PATENTS OR APPLICATIONS 17,219 2/1905 Great Britain 72/381 Primary Examiner-Lowell A. Larson AttorneyMaurice A. Weikart [5 7] ABSTRACT Disclosed is a device for continuously forming a metal sheet into sinuous or corrugated configuration by using two opposed, metal-engaging dies, each movable toward and away from the other in a vertical forming  U.S. Cl 72/385, 72/407, 72/452 Stroke, and one of the dies also being movable in a1im [5 e stroke transverse o its ca orming Stroke' Fleld of Search Slides moving o t y in c p ocating fashion, 72/407 452 have inclined surfaces which cause the vertical motion v of the dies. A latching and latch-releasing means, actu  Rekrences ated by the slides during the terminal increment of their UNITED STATES PATENTS horizontal motion at each end of their stroke, provide 2,489,125 11/1949 Dyson 72/452 the horizontal die stroke only when the dies have com- 3,009,510 11/1961 Meshulam 72/385 pleted their vertical stroke. 3,2l3,665 10/1965 Robinson... 72/385 3,430,476 3/1969 Duda 72/385 12 Clalms. 16 Drawing Flgures n 58 61 eg v69- 22 I 'liu PAIENTEU8EP25I975 3.760.624
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INVENTOR. JAMES J. ROBINSON BY MUM,MM,MW
ATTORNEYS SELF FEEDING CONTINUOUS FORMINGDEVICE This is a continuation, of application Ser. No.
1l1,375, filed Feb. 1, 1971, now abandoned.
BACKGROUND OF THE INVENTION Various types of apparatus-are known in theprior art for processing (forming, crimping, folding, perforating, etc.) sheet or strip material such as sheet metal. Examples of such prior art structures are disclosedin my US. Pat. Nos. 2,983,302, 3,003,540 and 3,213,665.
When the material being processed has unusual physical characteristics, such as exotic metal alloys used in heat exchanger fabrication, the problems in attaining high production speeds can be formidable. A satisfactory machine, designed to meet theseproblems must be relatively simple to set-up accurately, be capable of ac curate and convenient adjustmentandoperate troublefree at relatively high speed.
The present invention has the features mentioned above, these being primarily the result: of the arrangement for obtaining'the'vertical stroke. of both diesand providing a stationary, or dwell period for the dies-during which one die is movedfin atransverse,,or horizontal, direction. The transverse stroke in material-feeding; direction of the single die. so moved occurs while it is in extendedp osition so that it carries the. stockmaterial with it. This provides a self feedingfeature which accounts, in part, for the capability of'the machine for rapid, continuous operation. The. machinedraws in the necessary amount of stock to form the. desired configuration even though the gageof the material (thickness). varies somewhat. The forming; operation performed does not draw, stretch or thin the'material being processed. Entry of the sheet stock into the die area issuch that the stock can. be guided into the machine at an. angle so as to form the material into corrugations or broken away to preventobscuring. of the partsshown, illustrating the mounting and adjustment of the lower die.
FIG. 10 isa schematic illustration of the die position and corresponding die driver position at one portion of the stroke of the dies.
FIG. 11 is a schematic illustration of a. further point in the die stroke.
FIG. 12 is a schematic illustration. of a further point in the die stroke.
FIG. 13 is a schematic illustration of a further point in the die stroke.
FIG. 14- is a. schematic. illustration of a further point in the die stroke.
FIG. 15 is a schematic illustration of a still further point in the die stroke.
FIG. 16. is a schematic illustration-of the positions assumed by the. dies and the die driver as the cycle of motion. is completed.
DESCRIPTION OF THE PREFERRED EMBODIMENT wardly from whichextends rear side plates 11 and front side plates 12.. Rear end plate 13 and front end plate 14 (FIG. 2) complete the rectangular housing structure. Intermediate the length of the base plate 10, upright members l6serve to support the movable upper die assembly..
ridges which are angular, rather than transverse, with.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of apparatus embodying the present invention, the view being taken generally from the front of the machinev and with the side plates of the machine removed to reveal the underlying parts.
FIG. 2 is a top plan view of a-portion of the apparatus shown in FIG. 1 illustrating the driving mechanism.
FIG. 3 is an end view, with portions broken away, of the apparatus shown in FIG. 1.
FIG. 4 is an enlarged, detail view of the dies and die mounting means of the apparatus shown in FIG. 1.
FIG. 5 is an enlarged" side view of the means-for vertically moving the dies through their stroke.
FIG. 6 is a side view of the apparatus shown in FIG. 1.
FIG. 7 is anenlarged, detail view, taken from the side of the apparatus, illustrating the means for adjusting the horizontal stroke of the lower die.
FIG. 8 is an enlarged, fragmentary view illustrating the means for fine adjusting of theupper die.
Movable longitudinally within the housing formed by plates 11', 12', 13 and 14 isa frame composed of transverse members 19 and 21 and longitudinal slide members 22,.the slide members 22 being identical, inc'onfiguration. One of the identical slide members. 22 is shown schematically inFIGS. 10-16, and the slidemembers are visible in FIG. 1 where, it will be noted, the forward ends of the slides are bifurcated and'carry -roll'ers 23' which facilitate movement of the slides past the station- 5 ary vertical members adjacent to the slides. As may best be seen in FIG. 3 the movable frame moves along the underlying rails 24 which extend upwardly from the base plate 10. The portions of the slide which engage the rails 24 may be provided with wear plates or inserts 26 (FIG. 9') and stationary hold down blocks may be provided in overlying relation to the front portion of the slide to assure that its travel. is retained in a horizontal plane.
While other forms of drive means for the frame formed by the slides 22 might be utilized, the form disclosed includes a power means such as an electric motor (not shown) which drives the vertical stub shaft 27" (FIG. 2), the shaft havingfixed to it an eccentric throw arm 28' which has a pivotal. connection at 29 to a. motion transmission link 31 which is pivotally con nected: at 32. to the transverse member 19 of the frame. As'seen in FIG.'2. the drive means is at the. rear extreme of its-stroke and it will be understood that further rotation of the shaft 2.7 from its position of FIG. 2 will impel the frame and the component. slides 22 forwardly along the rails or ways 24, and further rotation of the shaft 21 will again return the frame to its rearward position of FIG. 2'. As indicated in FIGS. 10-16 each of the slides 22. is provided with an upper flat surface 22a and a lower flat surface 22b. The upper flat surface terminates with an inclined surface 22c and this upper inclined surface terminates at the flat surface of the upper face of the slide identified at 22d. The lower flat surface 22b terminates in the inclined surface 22e and this inclined surface terminates with the lower flat surface 22f. A portion of the length of the slide, adjacent the termination of the inclined surface 22e is identified at A, an additional portion is identified at B and a further portion of the slide is indicated at C in FIG. 10, the function of these surfaces and specified areas of the slides will be explained subsequently.
The metal forming apparatus includes upper and lower dies which move vertically toward and away from each other, the lower die also moving horizontally. The vertical movement of the upper and lower dies occurs as a result of the followers 31 and 32 (FIG. 5) traversing the upper and lower faces, respectively, of the slide 22. It will be understood that while the reference to followers 31 and 32 and slide 22 is made in the singular, there are two identical slides 22 and two identical followers 31 and 32 as will be evident from FIG. 3, the singular case reference, however, being utilized for clarity in describing the actuation vertically of the dies. The followers 32 are carried on the downwardly extending arms 33 of a transverse upper die support member 34 (FIG. 3). The upper surface of the slides 22 is engaged by the followers 31 supported on stub shafts 36 (FIG. 9). The followers or rollers 31 are supported in an lower die support member 37 (FIG. 9).
As may best be seen in FIGS. 4 and 9 the lower margin of the member 37 extends outwardly and seats a gage block 39 (the gage blocks 39 being spaced across the width of the members, only one being shown in FIGS. 4 and 9) which determines the vertical position of the stripper block 41 (carrying lower stripper member 42 (FIG. 4) and die holder block 43), the block 43 and block 41 being retained by the bolts 44 extending through elongated apertures in the blocks'4l and 43 and threaded into the member 37 as will be evident from FIG. 4. Supported on the block or bar 43 is the lower die, indicated generally at 48 FIG. 4) and formed by two plates 48a and 48b spaced from each other by a spacer 51 and held by;the retainer 52, the complete die assembly being attached to the member 41 by means of bolts 53. The lower die bed and stripper member 54 (FIG. 4), one margin of which is formed to provide the stripper 42 and the other margin of which is formed to provide the horizontally extending bed 54a, is spring biased upwardly from the driving block 37 by means of compression springs 56. The member 54 is guided horizontally by means of horizontal guide pins 57 (FIGS. 5 and 9). The rearwardly extending, horizontal bed 54a provides a means for transmitting a horizontal motion impulse to the lower die 48 as will be subsequently described with reference to FIG. 7. It will be understood that the use of interchangeable gage blocks 39 (FIG. 4) and the elongated apertures through which the bolts 44 extend, provide a means for conveniently adjusting or determining the height of the corrugation formed in the metal strip as it moves between the upper and lower dies.
Referring primarily to FIGS. 4 and 5, mounting of the upper die will now be described. The upper die, indicated generally at 58 in FIG. 4, is formed by two parallel die plates 58a, and 58b, spaced by the block 59. A die retainer member 61 serves to clamp the die assembly, by means of bolts 62, to the plate member 63. The plate 63, with the die 58 attached has elongated apertures which register with corresponding elongated apertures in the front plate 68 and these plates are attached by means of bolts 69 to the block 34. A comparison of FIGS. 4 and 1 will indicate the relative location of the bolts 69 and the plate 68. The block 34 has a portion 34a which extends outwardly in overlying relation to the upper edges of the plates 63 and 68. A depending portion of the part 340 (FIG. 8) extends downwardly and accommodates an adjusting screw 71 which engages a bevelled adjustment block 72 whose inclined upper surface is adapted to engage the inclined surface 73 of the part 34a which is adjacent to it. It will be evident that the position of the adjusting screw 71 determines the position of the die 58 and a lock bolt 74 serves to lock the adjustment made by the screw 71. This adjustment is used for accommodating the apparatus to a change in material gage or thickness and for final, minute height correction of the die should such correction be neded. It will be noted thatthis correction by means of the positioning of the block 72 can be made as the apparatus is in operation, this in-operation adjustment being important for precise forming.
Referring primarily to FIG. 5 it will be noted that the die mounting block of member 34 (shown without the die mounted upon it in FIG. 5) is supported on a stationary upright plate 76 attached to the vertical stationary support or way 16. An overlying cap plate 77,rigidly secured to the vertical ways 16 carries an adjustment screw 78 which is threaded through the member 77 and into the vertically extending portion 64a of the block 64. The adjusting screw 78 extends freely through the registering aperture in the flange 77 but is threaded into the die mounting member 64a so that while the upper die driver member 34 always moves through the same length of stroke, established by the roller 32 and its engagement with the under face of the slide members 22, the position of the die mounting member 64 with relation to the die driver block 34 is established by the adjusting screw 78 and therefore establishes the amount of opening between stripper members 42 and 66, FIG. 5, for the stock being formed, and clearance for the upward stroke of the lower die assembly 48, shown in FIG. 11.
The upper and lower dies 48 and 58 move vertically toward and away from each other in opening and closing strokes, however, the lower die 48 moves, additionally, in a horizontal direction in forward (with the flow of stock) and rearward (counter to the flow of the stock) strokes. The horizontal stroke of the lower die 48 and the drive mechanism for this horizontal motion of the lower die will now be described with particular reference to FIGS. 2 and 7. As may best be seen in FIG. 2, a bar 83, rectangular in cross section, extends across the housing and through the side plates 11. A rod 84, circular in cross section, also extends between and through the side plates 11, the apertures in the plates 1 1 through which the rod extends being enlarged as indicated in FIG. 6 where they are identified at 86. As will be evident from FIG. 6, a link member 87 is pivotally supported at 88 on the outer face of the side plates 11 and the links 87 receive the tip ends of the rod 84, it being understood that the structures shown in FIGS. 6 and 7 exteriorly of the side plates 11 is the same on both sides of the apparatus although only one such side plate mounted structure appears in FIGS. 6 and 7. Re-
turning to FIG. 2, the rod 84 carries rigidly attached to it depending lugs 89. Tension springs 91 are attached at their opposite ends to the bar 83 and to the rod 84 thus strongly biasing these two members toward each other. Each of the slides 22 support an upwardly extending roller or abutment 92 which engages the bar 83 at the rearward extreme portion of the stroke of the ac-v tuating member formed by the slides 22 and their connecting frame 19. The abutments 92 carried on the slides also engage thelugs 89 at the forward extreme portion of the stroke of the actuating member provided by the slides 22, this horizontal, reciprocating motion of the slides 22 being imparted by rotation of the shaft tric linkage to the transverse member 19 aspreviously described.
Referring primarily to FIGS. 6 and 7, it will be noted that the free end of the link 87 is bifurcated and pivotally connects the rod 93 to the link 87, the other end of the rod being pivotally connected at 94 to an L shaped member 96 which is pivotally connected at 97 to the side plate 11. The member 96 is formed by two identically shaped plates and between the plates is supported for rotation a roller 98, the roller 98 serving to reduce the friction between its surface and that of the link 99 which it engages. The link 99 is pivotally attached at 101 to the adjacent side plate 11 and is rigidly attached to the extending tip of the bar 83 at its free lower end. The link 99 carries a roller 102 the roller 102 engages the spanner wrench adjustable abutment 103 which can be adjusted with relation to the member 104 which is rigidly attached to and depends from the bed plate 54a, the locknut 105 serving to fix the adjusted position of the abutment 103.
The depending member 104 is split longitudinally and in the space thus provided carries a wedge shaped abutment element 106. A lock bolt 107 extends through an elongated aperture in the abutment member 106 and serves to lock the adjusted position of the abutment member 106 with respect to the depending in FIG. 2) and the abutments 92 will have engaged the lugs 89 carrying shaft 84 forwardly somewhat and pivoting the link 87 about its pivot 88 in a counter clock- I 27 and transmission of this motion through the eccen- I wise direction as viewed in F IGS'. 6 and 7. This angular movement of the link 87 will, by means of rod 93, move the latching member 96 into its position shown in FIG. 6 in which the latching action of the member 96 on the arm 99 is relieved and arm 99 assumes its position of FIG. 6 in which it is inclined rearwardly, the roller 102 thus permitting the abutment 103, block 104 and consequently lower die table 54a to be in their maximum rearward or lefthand (as viewed in. FIG. 6) position. The lower die table member 54a is spring biased rearwardly into its position of FIG. 6 by means of a series of compression springs 20 (FIG. 6) which extend 'between a depending flange 20a rigidly attached to the table 540 and the head of a spring retainer bolt 20d which extends freely through an aperture in the flange 20a and is threaded into the end plate 13. Thus, as soon as the lugs 89 are actuated by the abutments 92 so as to move shaft 84 into its position of FIG. 6, the consequent unlatching of the'member 99 permits the lower member 104, the relative position being first fixed by the adjusting screw 108 which may take the form of the two-way jack screw shown in FIG. 6. The lower inclined portion of the wedge shaped abutment is accommodated within a wedge shaped cavity 110 formed in a block element 111. The block element is held by lock bolts 112 which pass through horizontally elongated apertures in the block element. The inner ends of four set screws 113 engage the side margins of the block element 111. The set screws being threaded through a generally rectangular frame member 114 which is rigidly attached to the side frame plate 11.
In operation, a sheet of metal stock to be formed, identified at 121 in FIG. 10 is fed into the area between the dies from the rear of the apparatus, that is, over the surface directly above the shaft 27 and motion trans-- mitting link 31. Assuming the start of a forming cycle to be that in which the parts are in the positions shown in FIG. 10, the followers 31 and 32 will be in the positions shown with respect to the slides 22 and the upper die 58 will be in closed or lower position and lower die 48 will be in its lower or open position and at the rearward extreme of its horizontal travel. Under these conditions the stock 121 is fed between the dies to its initial position of FIG. 10. Under these conditions, the slides 22' will be near the forward end of their horizontal stroke the opposite extreme position from that shown die to'be driven by the spring 20 into its extreme rearward position illustrated in FIG. 10, and this position is retained even after the abutments 92 leave the lugs 89 in the progression of the slides 22 from their position of FIG. 10 toward the position of FIG. 11. As the motion of the slides 22 continues from its position of F IG. 10 into its position of FIG. 11 the lower die will vbe moved vertically upwardly by the traverse of the follower3l up the inclined surface 220. The upper die will remain in its position of .FIG. 10 since the follower 32 traverses only a horizontal area of. the lower side of the slide 22. This upward movement of the lower die 48 serves to form the stock as shown in FIG. 11.
As the slides 22 move from their position of FIG. 11 into their position of FIG. 12, the upper die will move to its upper or raised position because of the'traversing of the follower 32 over the inclined surface 22e. The lower die will remain in its position of FIG. 11 since the follower 31'traverses merely a horizontal surface on the slides. As the slides 22 move from their position of FIG. 12 to their position of FIG. 13, the upper and lower dies retain their vertical position, however, the lower die 48 moves horizontally into its forward position. This occurs because as the slides move into their extreme position of FIG. 13 (illustrated also in FIG. 2), the abutments 92 carried on the slides will engage the bar 83.
This engagement of the bar 83 moves it leftwardly as viewed in FIGS. 2, 6 and 7, causing clockwise angular movement of the member 99 about its pivot 101. As illustrated in FIG. 7, this movement of the member 99 causes the roller 102 carried at its free end to drive the abutment 103 rightwardly as viewed in FIGS. 6 and 7, thus moving the block 104 and the lower die table portion 54a rightwardly or forwardly, placing the lower die in its forward position of FIG. 13. Since the pivotal point of connection of the rod 93 to the member 87 is slightly above the pivotal connection of the rod 93 with the latching member 96 and because of the force exerted by springs 91, the latching member will move into its latching position of FIG. 7 as the member 99 drives the lower die forwardly thereby holding the lower die in this forward position even though the abutments 92 subsequently move out of engagement with the bar 83.
As the slides reverse direction and move from their position of FIG. 13 into their position of FIG. 14, the
lower die remains latched in its horizontal forward position. Since the follower 31 traverses a horizontal portion of the slide the vertical position of the lower die is unchanged. The upper die, however, moves into lowered or closed position because the follower 32 traverses the inclined face of the slide 22c. As the slides move from their position of FIG. 14 into their position of FIG. 15 the upper die retains its lowered position vertically and the lower die moves into open or lowered position while retaining its forward horizontal position. Further movement of the slides 22 from their position of FIG. 15 into their extreme position of FIG. 16 retains the upper and lower dies in their vertical position of FIG. 15, however, since the slides 22 are now in their opposite extreme position from that shown in FIG. 2, the abutments 92 carried by the slides will engage the lugs 89, moving the shaft 84 rightwardly as viewed in FIG. 2 and 6. This, through the rod 93, serves to move the latching member 96 into unlatching position (FIG. 6), releasing the roller 102 from the abutment 103 and permitting the lower die table portion 54a, and consequently the lower die 48 to be moved into its extreme rearward position by the springs 20 which bias the lower die table portion 54a, and consequentially the lower die, rearwardly into the position illustrated schematically in FIG. 16. The position of FIG. 16 marks the completion of a cycle and reversal of direction of the movement of the slide 22 causes the apparatus to pass again through the cycle illustrated in FIG. 10-16.
It will be noted that, as indicated at A, B and C in FIG. 10 there is a dwell or rest area on the slides following each vertical motion of the dies, this insuring that the motions of the dies must occur separately and not simultaneously. It will further be noted that the horizontal motion of the lower die in either direction can only occur after the slides have moved into the terminal increment of their travel in either direction, outboard of the areas A and C, so that this horizontal motion of the lower die also is segregated from the vertical motion of either the upper or lower dies. It should further be noted that the horizontal motion of the lower die occurs only at the terminal increments of the slide strokes, the lower die being driven in one direction horizontally by motion of the slides and spring biased in the other direction and released to follow its spring bias only as the slides move through the terminal increment of their horizontal motion in the opposite direction.
1. Apparatus for continuously processing a sheet of material fed into the apparatus, said apparatus including a first die extensible toward the stock in a closing stroke and retractable away from the stock in an opening stroke, a second die disposed adjacent the opposite side of the stock extensible toward the stock in a closing stroke and retractable therefrom in an opening stroke, the direction of the closing and opening strokes of said dies being parallel and normal to the plane of the stock, mounting means supporting said first die for movement in a direction normal to the direction of the opening and closing strokes of said dies, means for moving said dies through their opening and closing strokes comprising an actuating member having two spaced parallel faces and mounted for reciprocating motion and having an inclined surface on each of said faces, a first follower member adapted to engage one face of said actuating member and to traverse its inclined surface, as said actuating member is moved, a
second follower member adapted to engage the other face of said actuating member and traverse its inclined surface upon movement of the actuating member, means connecting said first and second follower members with said first and second dies respectively, and means for moving said first die transverse to the direction of opening and closing strokes of said dies comprising resilient means urging said first die to one extreme of its transverse motion, a driver element adapted when actuated to move said first die to the other extreme of its transverse motion against the force exerted by said resilient means, a latch member for retaining said first die at said other transverse motion extreme, and means carried by said actuating member for engaging and actuating said driver element during the final increment of the motion of said actuating member in one direction, and said means engaging and releasing said latch member during the final increment of the motion of said actuating member in the other direction, and power means for providing reciprocating motion to said actuating member.
2. An improved apparatus as claimed in claim 1 in which said inclined surfaces are displaced with relation to each other along the faces of said actuating member and positioned so that neither of said follower members engage said inclined surfaces during the final increments of motion of said actuating member in either direction, whereby no opening or closing motion of either of said dies or the transverse motion of said first die occurs concurrently.
3. An improved apparatus as claimed in claim 1 in which the opening and closing strokes of said dies are in a generally vertical direction with said second die being positioned above said first die and the reciprocating motion of said actuating member is generally horizontal and below said dies, the inclined surface of said actuating member engaged by said first follower member being on the actuating member face adjacent said dies and the inclined surface engaged by said second follower member being on the actuating member face remote from said dies.
4. An improved apparatus as claimed in claim 1 in which said means carried by the actuating member for engaging and actuating said driver element which moves the first die transversely and for engaging said latch member takes the form of a unitary abutment extending from said actuating element.
5. An improved apparatus as claimed in claim 1 in which the length of said transverse motion of said first die is established by adjustable stop means, said stop means including a table member secured to and extending from said first die in the direction of its transverse movement, a wedge-shaped abutment element and a block element having a wedge-shaped cavity therein adapted to receive said abutment element, one of said elements being movable with said table and the other being stationary, one of said elements being adjustably movable with relation to the other to thereby accommodate said wedge-shaped abutment element in the cavity to a depth corresponding to the adjusted relative positions of said elements with the transverse freedom of said abutment element in said cavity of said block element defining the freedom of said table member and hence of said first die for its said transverse motion.
6. An improved apparatus as claimed in claim 1 in which said latch member retains said first die by engaging said driver element.
7. An improved apparatus as claimed in claim 6 in which said driver element which is adapted to transversely move the first die does so by engaging an adjusting abutment rigidly mounted on said first die.
8. An improved apparatus as claimed in claim 7 in which said adjusting abutment is adjustably movable with relation to said first die to thereby vary the point in the travel of said driver element at which motion is transmitted to said first die and hence varying the stroke of the first die toward its said other extreme of transverse motion.
9. An improved apparatus as claimed in claim 7 in which said driver element includes an elongated member pivotally mounted intermediate its ends and adapted at one of its ends to engage said die mounted adjustable abutment and adapted adjacent its opposite end to engage said latch member.
10. Apparatus for continuously processing a sheet of material fed into the apparatus, said apparatus including a first die extensible toward the stock in a closing stroke and retractable away from the stock in an opening stroke, a second die disposed adjacent the opposite side of the stock extensible toward the stock in a closing stroke and retractable therefrom in an opening stroke, the direction of the closing and opening strokes of said dies being parallel and normal to the plane of the stock, mounting means supporting said first die for movement in a direction normal to the direction of the opening and closing strokes of said dies, means for moving said dies through their opening and closing strokes comprising an actuating member having two spaced parallel faces and mounted for reciprocating motion and having an inclined surface on each of said faces, a first follower member adapted to engage one face of said actuating member and to traverse its inclined surface as said actuating member is moved, a second follower member adapted to engage the other face of said actuating member and traverse its inclined surface upon movement of the actuating member, means connecting said first and second follower members with said first and second dies respectively, and means for moving said first die transverse to the direction of opening and closing strokes of said dies.
11. An improved apparatus as claimed in claim 10 in which said inclined surfaces are displaced with relation to each other along the faces of said actuating member and positioned so that neither of said follower members engage said inclined surfaces during the final increments of motion of said actuating member in either direction.
12. An improved apparatus as claimed in claim 10 in which the opening and closing strokes of said dies are in a generally vertical direction with said second die being positioned above said first die and the reciprocating motion of said actuating member is generally horizontal and below said dies; the inclined surface of said actuating member engaged by said first follower member being on the actuating member face adjacent said dies and the inclined surface engaged by said second follower member being on the actuating member face remote from said dies.