US3709024A

US3709024A - Forming press fixture

Info

Publication number: US3709024A
Application number: US00138126A
Authority: US
Inventors: R Grimoldi
Original assignee: Kaiser Steel Corp
Current assignee: PACIFIC TRANSCONTINENTAL Corp A CORP OF; Kaiser Steel Delaware Inc
Priority date: 1971-04-28
Filing date: 1971-04-28
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09

Abstract

An improved forming press fixture for selectively engaging, centering and balancing a workpiece upon and relative to the bed of the press during certain sequential press operations in order to effect selected folding or creasing of a workpiece.

Description

United States Patent [191 Grimoldi Jan. 9, 1973 [54] FORMING PRESS FIXTURE [56] References Cited [75] Inventor: Ranoldo H. Grimoldi, Napa, Calif. UNITED STATES PATENTS Assigneez Kaiser Steel Corporation Oakland Evans..... C l'f.

a Primary Examiner-Milton S. Mehr [22] Filed: April 1971 Assistant Examiner-R. M. Rogers Attorney-James E. Toomey, Paul E. Calrow and [2]] App! l38l26 Harold L. Jenkins [57] ABSTRACT [52] U.S. Cl .....72/420, 72/389 An improved forming press fixture for selectively [5 gaging centering and balancing a workpiece upon and Fleld of Search DIG. 1 relative to the bed of the press during certain sequen- 72/361, 389 tial press operations in order to effect selected folding or creasing of a workpiece.

9 Claims, 8 Drawing Figures !i Hi. [I /24' l h 53% 46 82 45 54 74 v .l W "I! z": L f1. "1 5- I l 25 58' 'l L7 15" a r" 5 23mm "is il si l rgst mw u "A 1" l"- 26a 4 4 g i; 1 I. h i r z I -n e e l |5 3 56 1] I6| I8. 26 I2 I20 I 1 1 l2 u I t i w/ n. l l. l

PATENTEDJAN- 9 197a SHEET 1 OF 3 INVENTOR. RANOLDO H. GRIMOLDI BY 7 W e. M

4 /L 4 4 1 n 1;. m m N. A bi ATTORNEY PATENTEDJAH ems 3.709.024

SHEEI 3 BF 3 46 FIG. 8

INVENTOR. RANOLDO H. GRIMOLDI gameim ATTORNEY- FIG. 5

FORMING PRESS FIXTURE BACKGROUND OF THE INVENTION This invention relates to a fixture for a metal forming press. More particularly it relates to an improved fixture for a press brake and the like which is useful in adapting the press to receive and hold the workpiece in the proper position during the selected creasing and folding of a metal workpiece and in particular a nonuniformly dimensioned workpiece.

Prior art presses such as press brakes were limited in their ability to crease and fold heavy gauge steel plates from plate sections of nonuniform dimensions such as plates having in a flat condition a somewhat truncated cone shape. Considerable difficulty has been experienced in mass producing tapered metal sections on such presses because of the delays and work stoppages occasioned in manipulating, arranging and rearranging the metal sections on the presses during the successive metal bending or folding operations. Examples of such slow acting prior art equipment having the aforesaid deficiencies are illustrated in US. Pat. No. 1,750,521 issued Mar. Il, 1930, and US. Pat. No. 2,825,431 issued Mar. 4, 1958.

The present invention represents an improved press brake fixture for use particularly in creasing or folding nonuniformly dimensioned heavy metal plate sections and the like to produce elongated taper poles or columns.

SUMMARY OF THE INVENTION The invention in general is directed to an improved press brake fixture that is readily attachable to a press brake bed and is operable to position, balance and center an irregularly shaped workpiece while it is folded at preselected spaced intervals along its length to form a symmetrically tapered polyhedral structural member or the like.

This fixture can include a box-shaped base element upon which are mounted adjustable guide plates that engage selected portions of the workpiece in order to balance, position and orient the workpiece relative to the press brake ram during various folding or creasing operations. The workpiece can be advantageously precisely centered relative to a press ram by means of these guide plates.

Unique pairs of adjustable, opposed and reversely oriented cradle arms cooperate with the guide plates in orienting, manipulating and balancing the workpiece during the creasing or folding operations. The ultimate result is a press that can handle and press form both regularly and irregularly shaped workpieces with equal facility.

The primary purpose of the instant invention is to provide a fixture capable of manipulating and balancing an initially flat tapered plate of trapezoidal shape that is progressively deformed on the press in an efficicnt and simple fashion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an end elevational view ofa press brake and illustrates a preferred embodiment of the forming fixture ofthe invention attached to the press brake;

FIG. 2 is a sectional view taken substantially along the line 2-2 of FIG. I;

FIG. 3 is an enlarged plan view with parts broken away and parts removed as viewed along line 3-3 of FIG. 2;

FIG. 4 is a schematic overall plan view of a typical flat trapezoidal shaped workpiece as held in a centered position relative to a press brake ram by the adjustable guide plates of the fixture of FIGS. 1 and 2 prior to the first creasing of the workpiece along a line coincidental with the center line of the workpiece;

FIG. 5 is a view generally taken along line 55 of FIG. 4 with parts added and other parts removed; and

FIGS. 6, 7 and 8 are schematic and successive crosssectional views of the workpiece shown in FIG. 5 as it is progressively and sequentially folded into a multifaceted and tapered section for a pole or the like by the press brake and fixture of the instant invention.

DETAILED DESCRIPTION With further reference to the drawings, FIGS. 1-8 illustrate a conventional press brake apparatus 10 equipped with a preferred embodiment of a fixture 11 of the instant invention in order to effect centering, balancing and folding of a workpiece W during progressive formation of the workpiece into a polyhedral shaped structural element such as, for example, the four-sided polyhedral element P indicated by dotted lines in FIG. 8. The apparatus 10 generally comprises a hollow rigiditied base 12 of approximately rectangular cross-sectional shape. The base is made up of interconnected plates that extend the full length of the apparatus and is mounted in suitable fashion on floor 14' of a building, all as indicated in FIGS. 1 and 4-5.

A die mount 16' is connected to the upper longitudinally extending ribs or rails 18' at the top of base 12 as depicted in FIGS. 1 and 5. Mount 16 at selected intermediate portions thereof between its ends is cut away so as to define a series of three cross slots 17 of channel shape for receiving a fixture 11, as shown in FIGS. 1 and 4. An elongated forming die 20 of channel shape is preferably affixed along the longitudinal center line of mount 16 at the upper surface of top plate 22 of the mount. The die 20' and mount 16' have individual lengths substantially the same length as base 12'. As shown in FIGS. 1, 4 and 6-8 intermediate portions of die 20 are cut away in the area of a given slot 17 so as to define an upwardly opening channelshaped slot for freely receiving a fixture 11. The rounded upper ends of opposed upstanding flanges or legs 23' of die 20' are adapted to engage the opposed bottom surface portions ofa workpiece W upon folding of the workpiece during operation of the apparatus, as will become more fully apparent hereinafter and as shown in FIGS. 1 and 4-8. An overhead press brake ram 24' is connected to and suitably suspended by a superstructure (not shown) over the press bed. The forming end 26 of ram 24' has a length that substantially corresponds to the length of die 20' and it is disposed in vertical alignment with die 20' as shown in FIG. 1. It is to be observed here that the cut away portions of the die 20' in the area ofa slot 17' are such as not to interfere with the remaining portions of the die during the uniform folding of a workpiece between its ends when the workpiece to be folded is interposed between ram end 26' and the remaining portions'of die 20 during operation of the apparatus.

In one embodiment of the invention a relatively flat workpiece W, preferably of trapezoidal shape in longitudinal section, is fed into apparatus 10from left to right, as viewedin FIG. 4 by way of an inlet conveyor (not shown). In order to facilitate advancement of the workpiece from the inlet conveyor (not shown) into apparatus 10 the apparatus can include a conveyor 28'. Conveyor 28 extends between the opposed ends of die mount 16' and is made up of two lines of rolls 30'. Each roll in a line of rolls 30 (only one roll ofa line of rolls is shown for the sake of brevity in FIG. 5) is disposed on either side of die 23 and mounted on the upper surface of plate 22' in such a fashion that the rolls of a given line of rolls 30' are disposed in longitudinal alignment on the upper surface of plate 22 between its ends on one side of'die 20'. As with die 20', the intermediate portion of a line of rolls 30 is cut away in the area of a slot 17'. The roll 30' of a series of rolls of conveyor 28 has a diameter such that the distance between the top of a roll 30' andthe top of plate 22' is greater than the distance between the top of the upper end of the flange 23' of a die 20 and the top of plate 22. By reason of the top of a roll being at greater distance above the top of plate 22' than the distance of the top of the leg 23' of die 20 above the top of plate 22, a workpiece W can be moved along conveyor 28 when the workpiece is manipulated within apparatus and/or advanced into and outof the apparatus during formation of a workpiece into element P without causing excessive wear to die It is to be understood, of course, that the diameters of the conveyor rolls 30 are such as not to adversely affect the folding of the intermediate part of a workpiece W within the recess 24 of die, 20' during apparatus operation, as will be more fully specified below. Upon forming ofa workpiece into an element P of polyhedral shape the element can be transferred from the press apparatus by conveyor 28' to other equipment for further processing, if desired.

A workpiece W is usually ofa length no greater than the length of apparatus 10. Depending upon the length of the apparatus, one or more fixtures ll of the instant invention can be disposed within the base or bed of apparatus 10 and operatively associated with opposite sides of plate W in the manner shown in FIGS. 1-8. Since each fixture 11 and the arrangement used for mounting each fixture in apparatus 10 are the same for all fixtures, a description of one fixture 11 and its mounting arrangement will suffice for all fixtures.

In an advantageous embodiment ofthe instant invention a fixture 11. is generally comprised of opposed support plates 12 disposed on opposite sides of mount 16 in a direction generally transverse of the longitudinal center line..C of apparatus 10. The inner end of a support plate 12 is affixed to the top surface portion of an intermediate part of rail 18' of mount 16' within the area of a cross slot 17', as best shown in FIG. I. The outer end is connected to the topof an upstanding floor mounted pier-type support 12a. A pair of support rails 13 are disposed upon and welded to a given plate 12 and are arranged in parallel and spaced relation to each other on the given plate crosswise of the centerline C of the press, as-indicated in FIGS. 1-3. The upper surfaces of supports 13 disposed on opposite sides of die mount 16 form ways for the bottom of the opposed ends ofa box beam 17 of fixture 11.

The fixture beam 17 is generally made up of top and side plates 18 and a bottom or platform 14 suitably interconnected together. The beam 17 has a length greater than the width of mount l6.so that the opposite ends of the beam 17 are connected to the. rails 13 on opposite sides of mount 16' throughout operation of apparatus 10 and fixture 11 during progressive formation of workpiece W into a polyhedral shaped element P. The platform .of beam 17 has a width substantially equal to the median distance between opposed rails 13 of a given pair of rails on either side of mount 16'. The platform width, however, is less than the width ofa slot 17. Upon disposition of an intermediate part of a platform of a beam 17 in the slot 17' opposed side edgesof platform 14 at opposite ends of the beam are disposed between and in nesting engagement with the uppermost surfaces of the opposed pairs of support rails 13, as shown in FIGS. 1-2. One ofa plurality of lock bars 15 is connected in conventional fashion by way of a series of cap screws 16 to its respective side edge portion of platform 14 at the opposite end of a beam 17 and to the upper stepped surface at the top of its associated rail 13, as illustrated in FIGS. l-2. Upon connecting each lock bar 15 to its respective rail 13, an opposed side edge of platform 14 at either end of beam 17 isslidably connected between its associated bar 15 and its respective rail 13. The height of beam 17 when the beam is fully inserted in a slot 17' of mount 16' is such that the upper surface of top plate 18 is not disposed above the bottom of the channel-shaped recess 24' of die 20', as shown in FIG. 1.

A piston and cylinder assembly 22 includes a cylinder 24. and a piston 23 disposed therewithin. The cylinder is affixed at its left end to an upstanding righthand plate 22a and is disposedin alignment with the right end of'platform 14 of beam 17. The lower end of righthand plate 22a is affixed to the outer end of right support plate 12 in FIG. 1. Similarly, a Iefthand plate 22a is affixed to the outer end of lefthand support plate 12 in FIG. 1 for a purpose that will become more apparent hereinafter. If desired, a plate 22a can be reinforced by angle-shaped elements 23a, as illustrated in FIG. I. The piston 23 of assembly 22 includes a piston rod 25 the outer forked end of which'projects through the left end of cylinder 24 and is connected by a pin 26 to an upstanding block 26a, as depicted in FIGS. l-2. The block 26a is connected to the right end of platform 14 in the manner illustrated in FIGS. l-2. Certain ends of

branch lines

28 and 30 are connected to opposite .ends of cylinder 24. A solenoid-operated control valve 32 is affixed to righthand plate 22a and is connected to the opposite ends of

lines

28 and 30. Input conduit 34 in FIG. 2 is connected to a fluid pressure source (not shown) and to valve 32. The valve 32 selectively directs fluid under pressure during operation of fixture 11 from input conduit 34 through either

conduit

28 or 30. Upon actuation of valve 32 and the directing of fluid under pressure from input 34 through either

line

28 or 30 the piston is advanced rightwardly or leftwardly in cylinder 24, thereby exhausting fluid through either

line

30 or 28, respectively, to valve 32, fluid return line 36, and a sump (not shown). When valve 32 is actuated, piston 23 is moved leftwardly or rightwardly, thereby causing corresponding leftward or rightward movement of rod 25 together with beam 17 in a direction generally transverse of mount 16 of apparatus l0.

Opposed and longitudinally aligned workpiece guide plates 38, each of right angular shape, are affixed to the upper surface portions of top plate 18 of beam 17 at opposite ends of the top plate.

Each guide plate is provided with slots 40 and is adjustably affixed to the upper surface of beam top plate 18 by cap screws 42 inserted in the slots 40 and anchored in threaded openings 44 in plate 18. In affixing guide plates 38 to opposite ends of beam 17, the op posed inner ends of the guide plates are spaced apart a distance somewhat greater than the maximum width of a workpiece in order to prevent jamming of the workpiece between the guide 38 as the workpiece is fed into the apparatus.

In another advantageous embodiment of the instant invention a fixture 11 includes a pair of J-shaped arms or fingers 46 disposed on opposed sides of beam 17 in reverse and opposed relation to each other. Since each finger 46 of the pair is mounted in the same fashion on opposite sides of beam 17 in reverse and opposed relation, a description of the mounting of one finger 46 will suffice for all such fingers. Opposed beam ends 18 are provided with transversely aligned openings 48.

Finger 46 is disposed against one of the beam side plates 18 such that the opening 50 in the outer end of finger 46 is aligned with openings 48 at one end of the beam, while the upwardly curved inner end of the finger extends in a direction towards the opposite end of the beam. A stub shaft 52 having an enlarged head 54 at one end is inserted through the finger opening 50 and through the aligned openings 48 of the opposed sides of beam 17 at one end of the beam, thereby pivotally connecting the finger to the beam. A cap screw and washer assembly 56 is suitably connected to the shank end of shaft 52, thereby securing the pivotally connected finger to beam 17 on one side thereof. If desired, either side 18 of beam 17 can be reinforced by an apertured washer l7 suitably affixed against an inside surface area ofa given side 18 of beam I7 and with the aperture of washer 47 disposed in alignment with beam opening 48 all as depicted in FIG. 2.

An actuating piston and cylinder assembly 58 is connected to the outer, straight end of the pivotally mounted finger 46, and an upstanding bracket plate 60 reinforced by a gusset plate 62 is connected to the top beam plate in offset relation to guide 38, as indicated in FIG. 2. The upper end of cylinder 64 of piston and cylinder assembly 58 is pivotally connected to and suspended from the upper end of bracket 60. The piston 66 disposed within cylinder 64 of assembly 58 includes a rod 68, the forked end of which projects outwardly of and through the lower end ofcylinder 64 and is pivotally connected to the outer or straight end of a finger 46.

Certain ends of

branch lines

70 and 72 for supplying fluid under pressure to either side of piston 66 within cylinder 64 are connected to opposite ends of the cylinder. A solenoid-operated control valve 74 is mounted on a given plate 22a and connected to the other ends of

lines

70 and 72. An input line 76 is connected to valve 74 and to a source of fluid under pressure (not shown). Thus, when righthand valve 74 is actuated and fluid under pressure is directed from input 76 through either line or 72 to either side of righthand piston 66 in FIG. 1, the righthand piston is moved upwardly or downwardly, thereby correspondingly moving its respective rod 68 in an upward or downward direction. This upward or downward movement of righthand rod 68 is translated into a pivotal movement of righthand finger 46 in a counterclockwise or clockwise direction about the shaft 52 of righthand finger 46 as viewed in FIG. 1. When fluid is directed from input 76 to righthand valve 74 and

line

70 or 72 to either side of righthand piston 66, fluid is exhausted from the opposite side of righthand piston 66 through

lines

72 or 70, valve 74, to outlet 78 and to sump (not shown) in the manner illustrated in FIGS. 1-2.

Either finger 46 has an overall length such that when, for example, a righthand finger is pivotally connected at its outer end to the right end of beam 17, the inner end of the finger is disposed on the lefthand side of the vertical center line 80 of apparatus 10 when the beam is disposed in a centered position relative to base 12 of apparatus 10 and within a cross slot 17' as indicated in FIG. 1. The upper edge or fingertip 82 of a fixture finger 46 is adapted to tangentially engage the bottom surface portion of a workpiece W when the workpiece is disposed within the apparatus 10 and between opposed guide plates 38 ofa given fixture. By reason of a pair of fingers 46 being pivotally connected to opposite ends of beam 17 of a fixture 11 in opposed and reversed relation to each other, each finger 46 can be selectively and independently pivoted relative to another finger and about its respective end of the fixture beam so as to selectively engage a bottom surface portion of a workpiece on either side of the vertical centerline 80 of apparatus 10.

An operative embodiment of a fixture 11 together with an apparatus 10, with which the fixture is associated, will now be described. A trapezoidally-shaped and relatively flat workpiece W is fed from left to right by a conveyor (not shown) onto the two series of rolls 30' of conveyor 28 of apparatus 10 until the ends of the fed-in workpiece are positioned between opposed and endmost fixtures ll of the apparatus 10 in the manner illustrated in FIG. 1. It is to be understood, of course, when a workpiece is fed into apparatus 10 that the beam of a fixture 11 will have been positioned within a slot 17' such that the inner ends of the opposed guides have been preferably preset at a distance apart somewhat greater than the maximum width of the workpiece as well as at a distance equidistant from either side of the longitudinal centerline C of apparatus 10 as shown in FIGS. I, 4 and 6-8.

Assuming that a workpiece is slightly off center, e.g., to the left in FIGS. 1, 4 and 6, the inner ends of opposed guides 38 ofa fixture 11 will be advanced to the right upon actuation of actuator 22 for advancement of piston 23 to the right whereby the inner end of left guide 38 eventually abuts the left edge of the workpiece so as to move workpiece W with respect to rolls 30 of conveyor 28 and forming die 23' until the center line of the workpiece is coincidental with the overall centerline C of apparatus 10, all as illustrated in FIGS. 1, 4 and 6. If the inner end of left guide 38 is advanced too far to the right thereby causing the workpiece to be slightly off center to the right in FIGS. 1, 4 and 6, the guides can be advanced in the opposite direction or to the left upon reverse actuation of actuator 22 for leftward movement of piston 23 until the inner end of righthand guide 38 abuts the right end of workpiece W and centers the workpiece and apparatus 10 between opposed guides 38 ofa fixture 11. Thus the opposed guides 38 of fixture 11 can be selectively manipulated in either direction transversely of the workpiece in apparatus 10 until the workpiece is properly centered between the apparatus and between the fixture.

Upon centering of the workpiece the ram 24' is advanced downwardly so that the forming end 26 of ram 24' engages and deforms the workpiece by effecting a center fold or crease in the workpiece in the manner indicated in FIG. 6. The depth of the recess 24' in die 20 is such. that it provides ample clearance between the creased or folded workpiece in the area of the crease and the bottom of the recess as indicated in FIGS. 1 and 6-8. By reason of the differencein height between the upper surface of a roll 28 and the upper end of a flange 23' of die 20' the upper ends of opposed flanges 23' of a die 20 will eventually engage opposed bottom portions of a centered workpiece as the forming ram end 26 of apparatus l advances toward die 20-with the workpiece interposed between the die and the forming ram and upon progressive folding of the work.- piece along its centerline during apparatus and fixture operations. When the upper ends of the opposed flanges 23 of die 20' engage inner opposed bottom portions of a centered workpiece upon advancement of ram 26 towards die 20' to form the workpiece between the die and ram, the outer opposed bottom portions of the workpiece become disengaged from the opposed inner ends of the two series of rolls 30' of conveyor-28 as shown in FIG. 6.

When opposed guides 38 of the fixture ll center a flat workpiece disposed therebetween, the pair of fingers 46 are normally disposed in a retracted out-of-theway position as shown by solid lines in FIG. 6. If desired, however, valve 74 operatively associated with the actuator 58 of each finger 46 can be designed to include biasing means (not shown) such that. the arcuate upper edge 82 at the inner end of each finger is biasingly pivoted upwardly. into engagement with its associated side of the workpiece as the workpiece is creased in the center in the manner disclosed by the dotted lines in FIG. 6. The opposed edge 82 of each finger 46 in maintaining a proper biased engagement with its associated side of the workpiece does not adversely affect the forming of the center fold line in the workpiece.

After forming ofthe initial and main center fold line in workpiece W, a further, e.g., left fold line is formed in the workpiece along the line located between the left edge of the workpiece and the main center fold line. all as indicated by the dotted line 82' in FIG. 4, as follows. After disengagement of ram 26' with the workpiece, the workpiece is shifted to the right with respect to die 20' until the fold line 82' of the left side of the single folded workpiece is centered in coincidence with center line C of apparatus 10. Since the left side of the single folded workpiece tends to pivot upwardly and out of contact with the roll 30 of apparatus 28' by reasonof the center of gravity of the single folded workpiece being located at the center fold line of the workpiece when the opposed guides 38 of a fixture are advanced for centering the left side of the single folded workpiece with respect to the line of advancement of ram 26', the lefthand finger 46 is pivoted counterclockwise the requisite amount until its fingertip moves into engagement with the right side of the single folded workpiece so as to maintain and stabilize the left:side thereof in its contact with the opposed rolls 30 of conveyor 28' and forming ram 26'.

During this rightward shifting of the single folded workpiece, the upper curved edge 82 at the left end of right finger 46 is pivoted counterclockwise to an out of-the-way retracted position so as not to interfere with the positioning of the workpiece for forming the left fold therein. When the left side of the single folded workpiece is centered in apparatus 10, ram 26' is advanced into engagement with line 82 of the left side of the workpiece so as to form the second fold therein. As the ram engages the left side of the workpiece the upper curved edge 82 at the right end of left finger 46 is biased in a counterclockwise direction in FIGS. 1 and 7 so as to maintain engagement with the righthand side of the workpiece during formation of the second fold therein. Thus the inner end of left guide 38 of a given fixture 11 and the upper curved edge 82 of left finger 46 of the given fixture cooperate to maintain the workpiece in centered and stabled relation between the left guide 38 and left finger 46 of a given fixture 11 and between ram 26' and die 20' of apparatus 10 upon formation of the second fold in workpiece W.

After formation of the second fold in the workpiece, the ram 26 is disengaged from the workpiece and the upper edge 82 of lefthand finger 46 is pivoted clockwise to a retracted position out of engagement with the workpiece while the upper edge 82 of righthand finger 46 is pivoted clockwise and into engagement with the workpiece until the righthand side of the workpiece is pivoted into planar contact with the rolls 30 of conveyor 28. As the upper curved edge 82 of right finger 46 is pivoted clockwise into engagement with the inner side of the double folded workpiece, right guide 38 of a fixture 11 is shifted in either direction until the third fold line 84 of a workpiece at the righthand side thereof is centered in coincidence with the longitudinal centerline C of apparatus 10 as indicated in FIGS. 1, 4 and 8. After the righthand side of a double folded workpiece is centered in apparatus 10 between right finger 46 and right guide 38 of a fixture, the upper edge 82 of right finger 46 ofa fixture 11 and the inner end of right guide 38 maintain engagement with the inner side and right edge of the workpiece respectively and cooperate to hold the right side of the double folded workpiece in centered relation between the ram 26' and die 23' as the ram 26' is advanced into forming engagement with the right side of the workpiece as indicated in FIGS. 1, 4 and 8. After the ram 26'forms the right fold in workpiece W the ram is withdrawn from engagement with the right side of the workpiece and the four sided structural element P is withdrawn from apparatus 10 and a fixture 11 prior to introducing another workpiece W to be formed between apparatus 10 and fixture II before another operative cycle of the apparatus and fixture.

From the above description it will be observed that one or more fixtures can be provided in apparatus 10 for effecting one or more desired number of folds in a given workpiece regardless of whether the workpiece is of a regular or irregular shape such as the trapezoidal shape of the workpiece illustrated. Even though a workpiece was formed by first forming the center fold, the left fold, etc., it is to be understood that the folds of a workpiece can be formed in any sequence.

Structural element P after being formed by apparatus 10 and fixture 11 can be placed in juxtaposition with an identical plate P as also formed by apparatus 10 and fixture 11 and welded together whereby the two juxtaposed plates would form a pyramid shaped polyhedral structural member of octagonal shape in cross section. Such a structural member could be used, for example, as a tower for a transmission line system and the like.

Advantageous embodiments of the instant invention been shown and described above, the invention is not to be limited except by the appended claims, wherein:

What is claimed is:

1. In a press brake and the like, comprised of a die move into and out of supporting engagement with selected bottom portions of a workpiece when the workpiece is disposed on said die means in order to fully stabilize the workpiece relative to the ram and said die means during the full advancement of said ram toward and into engagement with the workpiece on said die means.

2. A press brake as set forth in claim 1, including a conveyor means for conveying a workpiece into and out of said press brake and for at least partly supporting a workpiece within said press brake prior to advancement of said ram into engagement with the workpiece.

3. A press brake as set forth in claim 1 in which said die means includes a die of channel-shaped configuration in transverse section.

4. A press brake as set forth in claim 1, including a further fixture provided with a separate and independently mounted finger means.

5. A press brake as set forth in claim 4 in which said first and second fixtures and the finger means thereof are arranged in cooperating paired relationship to each other.

6. A press brake as set forth in claim 1 in which said finger means if of J-shaped configuration.

7. A press brake as set forth in claim 1 including an actuator means for said guide means.

8. A press brake as set forth in claim 1 including a separate actuator means for said finger means.

9. A press brake as set forth in claim 5 including a separate actuator means for each one of said first and second finger means.

Claims

1. In a press brake and the like, comprised of a die means and a ram disposed in an operative relation to said die means, a fixture for said press brake, said fixture being movably mounted adjacent said die means, said fixture including guide means for engaging the side edge of a workpiece disposed on said die means and for initially orienting the workpiece relative to said die means and said fixture further including at least one pivotally mounted finger means mounted in spaced relation to said guide means and adapted to pivotally move into and out of supporting engagement with selected bottom portions of a workpiece when the workpiece is disposed on said die means in order to fully stabilize the workpiece relative to the ram and said die means during the full advancement of said ram toward and into engagement with the workpiece on said die means.