US3686920A

US3686920A - Apparatus for producing corrugated dihedral blanks

Info

Publication number: US3686920A
Application number: US842482A
Authority: US
Inventors: Jean H Alleaume; Gilbert C F Fournier
Original assignee: Technigaz
Current assignee: Technigaz
Priority date: 1968-12-31
Filing date: 1969-07-17
Publication date: 1972-08-29
Anticipated expiration: 1989-08-29
Also published as: SE383692B; ES171399U; NL6911341A; FR1601215A; GB1245334A; ES393829A1; DE1935355C3; DE1935355B2; ES171399Y; ES369893A1; BE735918A; DE1935355A1; NO125548B

Abstract

Apparatus for producing a dihedral element with inwardly projecting corrugations. The uncorrugated dihedral or sheet metal blank is worked by punch and die members including a pair of lateral punches, having shaping edges in a common plane at an angle to each other and provided with adjacent sunk ends; a central punch between said ends; a die of complimentary configuration together with holding and retaining means; and means for relative synchronized and coordinate motions of the several tools.

Description

United States Patent Alleaume et al.

[4 1 Aug. 29, 1972 [54] APPARATUS FOR PRODUCING CORRUGATED DIHEDRAL BLANKS [72] Inventors: Jean H. Alleaume, Saint-Cloud; Gilbert C. F. Fournier, Le Havre, both of France [73] Assignee: Technigaz, Paris, France; by said Alleaume [22] Filed: July 17, 1969 [21] Appl. No.2 842,482

[30] Foreign Application Priority Data Dec. 31, 196 8 France ..68182929 [52] 0.8. CI ..72/399, 72/452 [51] Int. Cl. ..B2lj 13/02 [58] Field of Search ..72/399, 379, 395, 452, 381, 72/380, 385, 313, 305, 297, 356

[56] References Cited UNITED STATES PATENTS 1,561,556 11/1925 McMahoh ..72/399 2,010,996 8/1935 Junkers ..72/395 2,272,547 2/ 1942 COOrdCS ..72/ 399 2,798,388 7/1957 ECkOld ..72/395 3,025,905 3/1962 Haen' ..72/379 3 144,069 8/ 1964 Rutter ..72/ 379 3,425,260 2/ 1969 Anderson ..72/452 3,499,308 3/ 1970 Ford ..72/452 Primary ExaminerCharles W. Lanham Assistant ExaminerGene P. Crosby Att0rneyNolte and Nolte [57] 9 ABSTRACT Apparatus for producing a dihedral element with inwardly projecting corrugations. The uncorrugated dihedral or sheet metal blank is worked by punch and die members including a pair of lateral punches, having shaping edges in a common plane at an angle to each other and provided with adjacent sunk ends; a central punch between said ends; a die of complimentary configuration together with holding and retaining means; and means for relative synchronized and coordinate motions of the several tools.

14 Claims, 6 Drawing Figures mimmausgslsrz 31586320 sum 2 0F 5 INVENTORS JEAN H. ALLEAUME BYGILBERT C.F. FOURNIER ATTORNEYS PATENTEDauszs I972 Mi 3 OF 5 INVENTORS JEAN H. ALLEAUME GILBERT C.F. FOURNIER BY 7 m 17m ATTORNEYS PATENTED M1829 I972 SHEET U 0F 5 INVENTORS JEAN H. ALLEAUME GlLBE RT C. F. FOURNIER ATTORNEYS PATENTEmuszs 1912 I 3.686, 920

sum 5 or s 1 I I x ,116

INVENTORS JEAN H. ALLEAUME GILBERT C F. FOURNIER BY 7 m A 7 W ATTORNEYS APPARATUS FOR PRODUCING CORRUGATED DIHEDRAL BLANKS The present invention relates to apparatus for producing corrugated corner pieces (dihedral) for contamers.

Corrugated corner pieces are already known, which are made for instance of sheet metal, and are provided with at least one corrugation projecting from the inner side and on each face of the dihedral angle. Such a corrugation has two corrugation portions, one on each of the two adjacent faces of the dihedron. Such pieces which may be provided with several of the said parallel corrugations, for instance in spaced relationship, and which may have any desired length in a direction parallel to the crest of their dihedron, are used in particular as connecting or corner elements between two walls of an enclosure.

The apparatus comprises on the one hand at least one pair of movable lateral punching knives or like male forming tools for forming respectively the two corrugation portions in the two walls or faces of the aforesaid dihedron and at least one movable central punching tool for forming the intermediate projecting dihedral portion, and on the other hand at least one movable die or like female forming tool having preferably a deformable or variable configuration, as well as holding or retaining means for preventing any relative sliding displacement of the sheet metal blank being worked with respect to the said tools.

The invention will be better understood and other objects, characteristics, details and advantages thereof will appear as the following explanatory descriptions proceeds with reference to the appended diagrammatic drawings given solely by way of example illustrating one form of embodiment of the invention and wherein FIG. 1 is a perspective view of the corner piece according to the invention, the dihedral angle of which forms substantially a right angle;

FIG. 2 is a diagrammatic profile or side view of a corner piece with an obtuse dihedral angle;

FIG. 3 is a diagrammatic view of the piece of FIG. 2 developed in a single plane showing the various folding lines;

FIG. 4 is an elevational view of a forming device according to the invention seen in vertical section upon the line IV-IV of FIG. 5, at right angles to the crest of the aforesaid dihedron;

FIG. 5 is a vertical axial sectional view taken along the line V-V of FIG. 4; and

FIG. 6 is a fragmentary cross-sectional view of the same device taken along the lines VI-VI of FIG. 4, wherein the movable members are shown in the same position as in FIG. 5.

According to the form of embodiment illustrated in FIG. 1, the corner piece of sheet metal 1 is folded so as to form a dihedron, the angle 0 of which is shown as a substantially right angle. Each face of this dihedron is provided with a substantially dihedral corrugation or wave 2, 2 projecting towards the interior of the dihedron and extending at right angles to the crest 3 of the latter, so as to be symmetrical with respect to a plane extending at right angles to the crest 3 and containing the crest lines of the two waves 4, 4'. The piece 1 may of course be provided with several parallel waves 2, 2' spaced along the crest 3 or ZZ.

Each

crest line

4, 4 terminates near crest 3 at a point B, B where it bifurcates so as to divide into two divergent, inwardly convex folds having crest lines BA, BA and BA, B'A'. The crest ZZ meets these divergent fold lines respectively, at points A, A of intersection between the crest and the fold lines. From each end of the crest lines B, B there also extends a third fold, having crest line BC, and B'C and which is inwardly concave and re-entrant and the ends C and C of which are connected to the said points A, A, respectively by still further concave folds with crest lines CA, CA and C'A, C'A', the points C, C being joined by a convexfold line C C.

FIG. 2 is an elevational view in profile of a folded corner piece similar to the piece 1 of FIG. 1, but having an obtuse dihedral angle, whereas FIG. 3 shows the plane development of the piece of FIG. 2 with reference figures corresponding to those of FIG. 1. The concave-fold lines at the base of the waves are denoted by X A X and Y AY, while the crest lines are denoted by Y, B and Y B. It is seen that the common connecting surface between the two

corrugations

4 and 4 in the angle of the dihedron is a skew polyhedral surface with adjacent triangular facets, comprising two reentrant dihedral portions B C A A and B C A A forming respectively the mutually confronting, terminal surfaces of the two waves and an intermediate projecting dihedral portion C C A A, respectively adjacent to the two re-entrant dihedral portions and interconnecting the latter. In order to avoid any extension of material outside the dihedron, that is projecting on its external faces, it is necessary that the points C and C should not lie outside the plane of the faces of the dihedron 1, that is they may at most occupy the position shown in FIG. 2, and therefore be located in either plane of the dihedron. In FIG. 2 it is assumed that the angle of the corrugations 2 and 2 is zero, i.e. the side or lateral faces of these waves are brought together so as to coincide or be parallel to one another. Assuming,

Since in order to obtain FIG. 3 from FIG. 2 the sheet must be entirely unfolded, the angle CAC' which was coincident with the dihedral angle XAX' 0 is flat and unfolded, so that the angle CAC' may be considered to be the flat unfolded view of the dihedral angle 0. Therefore The following condition must of course be fulfilled:

or again WlIOI'CfIOIIl it. finally follows:

The intermediate projecting dihedral crest portion CC, interconnecting the two waves 2, 2' comprises in its crest a substantially central imprint or depression 4a which is approximately dihedral and extends transversely of the said crest and over at least part of the height of the said portion.

FIGS. 4 to 6 illustrate the forming or shaping device for obtaining a complete corrugation 2, 2 in a sheetmetal element 1 previously folded to form a dihedron, the principle upon which this device is based being of course applicable to simultaneous shaping of several such corrugations, parallel spaced on one and the same sheet previously folded to form a dihedron. The device is for instance adapted to be mounted on a folding press, the stationary clamping table of which is denoted by the reference numeral 5, while the movable plate of the press is shown at 6 and is rigid with the vertical slide 7 of the press. The table 5, which is for instance substantially horizontal, carries a stationary structure 8 forming a clamping pad or the like which itself carries a die 9 whose upper surface has a configuration corresponding to the internal finished shape of the sheetmetal blank 10 folded to form a dihedron and corrugated to provide the raised and sunk portions of the finished corner piece 10.

The device as a whole is preferably substantially symmetrical with respect to the bisecting plane of the dihedron of the finished corner piece placed in the device and with respect to the normal medial longitudinal plane of the said corrugations.

The die 9 is composed of two elements or half-

dies

9a, 9b arranged substantially symmetrically with the plane extending at right angles to the crest of the said dihedron and passing through the crest lines of the said corrugations, the said half-dies being symmetrically movable in opposite directions with respect to one another, so as to be capable of simultaneously moving towards or apart from one another in a direction at right angles to the said plane. The hollow form or mould for forming each wave 2, 2' is therefore divided into two symmetrical half-forms 11a and 11b as shown in FIG. 6. Similarly, the hollow form for forming the intermediate projecting dihedral crest portion C C is also separated into two symmetrical portions 12a, 12b as shown in FIG. 5. Each half-

die

9a, 9b is movable in circular translation and is connected to the stationary base structure 8 through the medium of a plane articulated control system forming preferably an articulated parallelogram or like guiding mechanism. Such mechanism for each half-die is shown as comprising a pair of links, journalled pins or like rigid members 13, each having two ends, articulated respectivelyon the half-die and on the stationary structure 8 by means of pivot pins l4, 14. In the form of embodiment illustrated in FIGS. 4 and 5, each articulated connection is obtained through the medium of, e.g., two sets of three substantially co-axial or aligned crank-shafts 15, the crankpins or journals of which are rotatably mounted in suitable bearings in the stationarystructure 8 and the pivot pins 14 of which are rotatably mounted in suitable bearings rigid with the relevant half-

die

9a, 9b.

The maximum horizontal clearance position of the two half-

dies

9a, 9b, as shown in FIG. 5, is ad vantageously determined or defined respectively by two stationary stops 16, 16', which may be solid with the stationary structure 8 and each constituted preferably by an inclined plane wall surface cooperating with a corresponding plane wall surface of the respective associated half-

die

9a, 9b. In this position of maximum clearance between the two half-dies each plane containing the axes of the two

pivot pins

14, 14 of an articulated connecting member 13 of a half-die is preferably inclined to the other half-die, that is in the direction of initiation or starting of the motion of the two half-dies towards one another, in order to promote the starting of this motion.

The two mutually confronting waves of each corrugation of the dihedral corner piece 10 are pressformed, respectively, by lateral punching members 17a and 17b, while the intermediate connecting portion is pressed-formed by a central punch-member 18.

Return means, eventually automatic, such as springs or compressed-fluid actuating devices are advantageously provided to preferably simultaneously move the said half-dies back to their initial position of maximum clearance. In FIG. 5 such a return spring 33 is shown to be placed between the two half-dies so as to bear against each of the latter in a suitable embedment recess 34, 34'. In a modified embodiment, the return mechanisms may also act upon the elements 13 or upon their pivot pins.

Each lateral punching member 17a, 17b is rigid with a driven punch-carrying

block

19a, 19b resting in guided sliding or rolling contact upon a corresponding guiding

wall

20a, 20b of the die 9, i.e. of the respective half-

die

9a, 9b. Each of these guiding walls has a preferably substantially planar surface at right angles to the die wall 21a or 21b carrying an associated face of the dihedron of the corner piece 10 and parallel to the crest of the latter. The corresponding surface of each

block

19a, 19b which is in contact with the associated

plane face

20a, 20b of the die is also preferably plane.

Central punching member 18 is rigid with a driving punch-carrying block 22. This block is movable in a direction parallel to the bisecting plane of the dihedron of the corner piece 10, i.e., in this case, substantially vertically, be resting in sliding or rolling contact simultaneously upon the two lateral punch-carrying

blocks

19a and 19b, respectively along a contact interface or separating

surface

23a, 23b which is substantially planar, parallel to the crest of the said dihedron and inclined to each associated corresponding guiding wall of the die 9, so that the combined motions of the three

tools

17a, 17b and 18 are geometrically and kinematically compatible with the configuration of the portions to be shaped. The central punch-carrying block 22 is made rigid with the press upper plate 6 which during its downward motion moves nearer to the table 5 and during its upward motion moves apart therefrom.

Guiding means are provided respectively between .t ,e sh-si ymk skal a19 1 the one hand and the die 9 and the central punch-carrying block on the other hand. These guiding means are advantageously constituted by at least one slideway or like sliding or rolling path 24, e.g. of the slot-and-tongue type, such as illustrated in FIG. 6 which shows the guiding of the lateral punch-carrying block 19a on the central punchgcarrying block 22.

Each die 9 may of course comprise of a die-carrying block supporting the die proper.

The combined motions of the three punches or

tools

17a, 17b, 18 and of the two half-dies or die-carrying blocks 9 must ensure, without relative sliding or mutual displacement of the sheet-metal element with respect to these half-dies, the application of the sheet on the one hand against the punches and on the other hand against the half-dies, so that upon completion of the motions the punches and the half-dies perfectly confine the sheet. Holding or retaining means are provided to prevent any general or total slipping or displacement of the sheet with respect to the punches and the half-dies for the whole duration of the shaping operation. These means are advantageously constituted by at least two pairs of blank or sheet hold-down

clamps

25a, 25b and 25'a, 25'b placed respectively on either side of each lateral punch-

member

19a, 19b and ensuring the clamping of the sheet against the die 9 during the approaching motion of the punch-members towards the said die by bearing on the one hand upon the said sheet and on the other hand against the

lateral punchcarrying blocks

19a, 19b, preferably through the medium of resilient elements or pads such as springs 26 or of hydraulic or pneumatic actuating devices.

Since each lateral punch-carrying

block

19a, 19b extends substantially over the whole width of the central punch-carrying block 22 (see FIG. 6), it cannot follow the motion of the half-dies 9a, 9b towards each other, the said motion being automatic and caused solely by the vertical downward pressing force exerted by the press plate 6. It is therefore necessary to interpose between each blank hold-down clamp and the sheet 10 to be worked an

intercalated plate

27, 27 in sliding or rolling contact with the said blank hold-down clamp, the two plates located on one and the same side of the lateral punch-members 17a, 17b being preferably rigid with one another and forming a bent or

angle element

27, 27 forming a dihedron corresponding in shape to that of the sheet 10. In case of sliding contact between the

element

27, 27 and the said blank hold-down clamps, this contact may take place through the medium of lubricated plane surfaces, whereas in case of rolling contact the latter can be obtained by interposing rolling members such as balls, rollers or the like.

In order to enable, upon completion of the shaping operation, the freeing of the finished corner piece 10 from the device and the placing of a new blank to begin a new operating cycle, means are provided for automatically moving off the lateral punch-members and the associated blank hold-down clamps of the aforesaid die, during the off motion of the central punchmember, the control of these means being preferably interdependent with the off motion of said central punch-member. These means are preferably constituted by the bearing plates of the said blank hold-down clamps which are made rigid with one another in pairs a, 25b and 25'a, 25'b so as to form two one-piece or solid bearing plates 25, 25' bent respectively to form a dihedron corresponding .in shape to that of the sheet 10 stem.

and both connected unilaterally to the central punchcarrying block 22, so as to be raised and suspended by the latter in its maximum clearance position from the die, but enabling them to freely move towards the central punchcarrying block. According to one form of embodiment, each bent bearing plate 25, 25' is made rigid through the medium of its projecting bend with a stem or the like 28, 28' normal to the surface of the said plate and parallel to the bisecting plane of the said dihedron, i.e. substantially vertical. Two such stems are shown, one on either side of the central punch-member 18. Each stem is mounted so as to be freely slidable in the central punch-carrying block 22 and is provided with means for stopping its outward, i.e. downward, motion, the said means consisting of a head, a collar, a shoulder, a flange or a pin projecting radially and adapted to make contact with a similar stop or shoulder rigid with the central punch-carrying block. According to the form of embodiment illustrated, each stem 28, 28' freely slides in a substantially

vertical bore

29, 29 provided in the punch-carrying block 22, the said bore opening at its lower end on the outside and at its upper end into a cylindrical or prismatic cavity 30, 30' (FIG. 5) of the punch-carrying block 22. The upper end of each said stern engages into the associated cavity and is advantageously provided at its end with a head or the like 31, 31' protruding laterally and mounted with clearance so as to be freely movable inside the associated cavity. Each head is adapted to engage, at the end of the downward travel of the associated stem, the lower bottom 32, 32 of the corresponding cavity, thus limiting the magnitude of the outward motion of the Bach intercalated

plate

27, 27 is advantageously connected to the corresponding bearing

plate

25, 25 of the associated blank hold-down clamps so as to automatically move away from the die during the off motion or withdrawal of the said hold-down clamps while at the same time being freely movable in a direction parallel to the said bearing plate. To this end, each intercalated plate is connected to the associated bearing plate by means of, for instance, a sliding articulation constituted by at least one pin 35 provided with a head rigid with the intercalated plate and traversing a longshaped opening 36 provided in the bearing plate in which it is movable.

This device operates as follows initially, the slide 7 of the press and the associated press plate 6 are raised to their maximum upper position, so that the central punch-carrying block 22 occupies itsmaximum upper position in which the blank hold-down clamps 25, 25 are suspended by means of the stems 28, 28' from the central punch-carrying block 22 away from the die 9, while the intercalated plates 27, 27' are suspended from the hold-down clamps by means of their pins 35 away from the die 9. As a result, the lateral punch-carrying

blocks

19a, 19b which normally rest at least partially upon the said hold-down clamps are also raised by the latter away from the die 9 by sliding along the plane surfaces 20a, 20b of the latter. On the other hand, the two half-dies 9a, 9b are moved away from one another by spring 33 until they abut against the surfaces 16, 16' of the base 8. A sheet-metal blank 10 previously folded in the shape of a dihedron is then arranged on the die 9. The press plate 6 and, therefore, the central punch-carrying block 22 is caused to move downwards, whereby the block 22 acts simultaneously upon the lateral punch-carrying

blocks

19a, 19b, compelling them to move towards the die and perform the shaping of the sheet 10. At the same time, under the action of the pressure exerted by the central punch-carrying block 22 upon the die 9 through the medium of the lateral punch-carrying

blocks

19a, 19b, the two half-dies 9a and 9b are compelledto move progressively towards one another during the shaping operation, for instance until they engage with one another and/or with the base 8. As soon as the blank hold-down clamps 25, 25' guided by the stems 28, 28' engage respectively the bent

intercalated plates

27, 27 which themselves are in contact with the sheet 10, the stems 28, 28' are immobilized but the downward motion of the central punchcarrying block 22 is not stopped owing to the fact that the cavities 30, 30' have sufiicient free height to allow the necessary upward relative displacement of the slums 28 while central punch-member 18 moves in downward direction. During this downward motion, the blank hold-down clamps are compressed and eventually resiliently collapse while they enable the lateral punch-carrying blocks to continue to move downward.

The inclination of the two sliding

planes

23a, 23b is selected so that the driving-in motions of the three punch-members, directed at right angles to the base plane of the sheet to be shaped, take place according to a suitably selected ratio which is compatible with the desired shapes. On the other hand, the tilting guiding mechanism 13-15 of the two half-dies 9a, 9b imparts to the latter the necessary degree of freedom to enable them, through the medium of the sheet pressed by the hold-down clamps, to conveniently combine their motions with the downward motions of the three punchmembers.

During the upward motion of the plate 6 the various movable parts move according to a sequence reverse to that previously described.

The sheet is pre-formed between the three

punchmembers

17a, 17b and 18, to a shape corresponding to minimum elongation of the material. Uniform shaping of the sheet is facilitated as two half-moulds are provided in the connecting zone at the top of the half-dies 9a, 9b.

The corrugated corner piece 10 thus obtained is not yet the completed piece, i.e. the piece in its finished state. At the end of the shaping operation, the dihedral angle generally exceeds the dihedral angle to be obtained finally. A complementary finishing machine imparts to the top of the small wave C C connecting the two main waves 2, 2 a slight deformation or imprint 4a obtained by means of a punch-member arranged at right angles to the crest of the said small wave and which acts so as to reduce the dihedral angle, thus imparting additional resiliency or suppleness allowing for angular variation of the dihedron.

The corner piece obtained may also be subjected, by means of a complementary tool assembly, to a further deformation in order to modify the shape of the wave obtained on each face or half-plane of the dihedron. This deformation may be the same for both half-planes or faces or alternatively, may be different when it is required to interconnect waves of unequal magnitude located in different planes.

It is to be understood that the invention should not be construed as limited to the embodiments described and shown which have been given by way of illustration only, as many modifications and alterations may be resorted to by those skilled in or conversant with the art without departing from the gist or scope of the invention. In particular it comprises all the means forming technical equivalents to the means described as well as their combinations, if they are carried out or put into practice according to the spirit, principles and teachings of the invention as defined in the appended punch-members each having a substantially straight shaping edge, both punch members being arranged so that said shaping edges are located substantially in a common plane at an angle to each other and being provided with adjacent sunk ends, said lateral punch-members constituting male forming tools, and at least one movable central dihedral punch-member intermediate said adjacent sunk ends, said central dihedral punch member having a substantially straight shaping edge in said common plane and on the other hand at least one movable die constituting a female forming tool having a variable configuration combined with and complementary to that of said punch-members in order to cooperate therewith, as well as blank holding and retaining means and means for interdependent automatic control providing relative synchronized and coordinate motions of said male and female forming tools in forced positive mutual guiding relationship so that said punch-members move together in translation in parallel relation to said common plane.

2. A device according to claim 1, wherein said die is formed with a pair of concave dihedral recesses located in registering relationship with said lateral punch-members and each one comprising a blank supporting side and a punch-member guiding side, said sides extending at right angles to said common plane and wherein each lateral punch-member is rigid with a driven lateral punch-carrying block resting in movable contact-upon the guiding side of the associated recess.

3. A device according to claim 2, wherein said central punch-member is rigid with a driving central punch-carrying block movable in parallel relation to said common plane by resting in movable contact simultaneously against said two lateral punch-carrying blocks, respectively, along a contact interface which is substantially planar, extending in a direction parallel to said common plane and inclined with respect to each aforesaid corresponding associated guiding side of said die.

4. A device according to claim 3, comprising guiding means, between said lateral punch-carrying blocks on the one hand and said die and said central punch-carrying block on the other hand, said guiding means being constituted respectively by at least one slideway of the slot-and-tongue type.

5. A device according to claim 1, wherein each die is composed of two elements forming half-dies substantially symmetrical with respect to said common plane, said half-dies being symmetrically movable in opposite directions with respect to one another.

6. A device according to claim 5, wherein each halfdie is movable in circular translation and connected to a stationary base structure forming a clamping plate through the medium of a plane linkage control system consisting of a hinged parallelogram forming a parallel motion guiding mechanism, comprising two opposite rotatable sides which are constituted by at least two links pivoted respectively to said half-die and stationary structure.

7. A device according to claim 6, comprising a pair of stationary stops rigid with said stationary structure and adapted to set a maximum clearance position of said two half-dies and wherein each one of said links is pivoted through two pivot axes lying in a plane which is inclined in said maximum clearance position towards said plane of symmetry of said die in the direction of initiation of the motion of the two half-dies towards each other.

8. A device according to claim 2, wherein said blank holding and retaining means are constituted by at least two pairs of blank hold-down clamps arranged respectively on either side of each lateral punch-member and bearing against said lateral punch-carrying blocks through the medium of pushing elements.

9. A device according to claim 8, wherein each one of said blank hold-down clamps is engageable with an intercalated plate in movable contact with said holddown clamp, and interposed between the latter and said die, both plates located on the same side of said lateral punch-members being rigid with one another and forming an element bent to a dihedron.

10. A device according to claim 9, wherein each aforesaid hold-down clamp is provided with a bearing plate, said bearing plates being rigid with one another by pairs so as to form respectively two bearing plates bent in the shape of a dihedron and connected respectively unilaterally to said central punch-carrying block, so as to be raised and suspended from the latter in said position of maximum clearance while at the same time allowing them to freely move towards the latter.

11. A device according to claim 9, wherein each bent bearing plate is made rigid by its projecting bend with a rod normal to its surface and located in the bisecting plane of said dihedron and mounted freely slidable in said central punch-carrying block, said rod comprising means for stopping its outward motion, constituted by a carrying block, both rods being arranged on either side of said central punch-member.

12. A device according to claim 1, said punch-members being substantially symmetricalwith respect to the bisecting plane of said dihedron.

13. A device according to claim 5, wherein automatic return means are provided to simultaneously move said half-dies back to their initial position of max imum clearance.

14. A device according to claim 9, wherein each intercalated plate is connected to the bearing plate of the associated blank hold-down clamps, so as to automatically move away from said die during the withdrawal of said hold-down clamps, while at the same time being freely movable in parallel relation to said bearing plate.

Claims

1. In a manufacturing device for shaping a dihedral sheet metal blank and constituting a folding tool assembly comprising punches and dies and adaptable to a folding press-like shaping machine, the improvement consisting in that said device comprises on the one hand at least one pair of movable lateral dihedral punchmembers each having a substantially straight shaping edge, both punch members being arranged so that said shaping edges are located substantially in a common plane at an angle to each other and being provided with adjacent sunk ends, said lateral punchmembers constituting male forming tools, and at least one movable central dihedral punch-member intermediate said adjacent sunk ends, said central dihedral punch member having a substantially straight shaping edge in said common plane and on the other hand at least one movable die constituting a female forming tool having a variable configuration combined with and complementary to that of said punch-members in order to cooperate therewith, as well as blank holding and retaining means and means for interdependent automatic control providing relative synchronized and coordinate motions of said male and female forming tools in forced positive mutual guiding relationship so that said punchmembers move together in translation in parallel relation to said common plane.

2. A device according to claim 1, wherein said die is formed with a pair of concave dihedral recesses located in registering relationship with said lateral punch-members and each one comprising a blank supporting side and a punch-member guiding side, said sides extending at right angles to said common plane and wherein each lateral punch-member is rigid with a driven lateral punch-carrying block resting in movable contact upon the guiding side of the associated recess.

6. A device according to claim 5, wherein each half-die is movable in circular translation and connected to a stationary base structure forming a clamping plate through the medium of a plane linkage control system consisting of a hinged parallelogram forming a parallel motion guiding mechanism, comprising two opposite rotatable sides which are constituted by at least two links pivoted respectively to said half-die and stationary structure.

9. A device according to claim 8, wherein each one of said blank hold-down clamps is engageable with an intercalated plate in movable contact with said hold-down clamp, and interposed between the latter and said die, both plates located on the same side of said lateral punch-members being rigid with one another and forming an element bent to a dihedron.

11. A device according to claim 9, wherein each bent bearing plate is made rigid by its projecting bend with a rod normal to its surface and located in the bisecting plane of said dihedron and mounted freely slidable in said central punch-carrying block, said rod comprising means for stopping its outward motion, constituted by a flange projecting radially, adapted to make contact with a similar stop means rigid with said central punch-carrying block, both rods being arranged on either side of said central punch-member.

12. A device according to claim 1, said punch-members being substantially symmetrical with respect to the bisecting plane of said dihedron.

13. A device according to claim 5, wherein automatic return means are provided to simultaneously move said half-dies back to their initial position of maximum clearance.