Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
  • B21D39/00—Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating; Tube expanders
  • B21D39/02—Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating; Tube expanders of sheet metal by folding, e.g. connecting edges of a sheet to form a cylinder
  • B21D39/021—Application of procedures in order to connect objects or parts, e.g. coating with sheet metal otherwise than by plating; Tube expanders of sheet metal by folding, e.g. connecting edges of a sheet to form a cylinder for panels, e.g. vehicle doors

Definitions

• the present invention relates to a pre-crimping and crimping unit for the edge of a sheet which is supported by a fixed die.
• It also relates to a tool composed of a set of several units of this kind, juxtaposed.
• a well-known method for joining two sheets is to crimp the edge of one of them against that of the other.
• the edge to be crimped is bent at 90 ° to the rest of the sheet.
• the crimping operation consists, in a first step, in partially folding it down - generally at an angle of 45 ° - in the direction of the other sheet.
• the actual crimping, carried out in a second step corresponds to the complete folding down of the sheet metal edge, which comes to bear against the edge of the other by pinching it.
• This type of operation is traditionally carried out in a press, on an open table with a mobile hydraulic matrix, or on a fixed matrix using tilting blade-holder carriages.
• an objective of the invention is to control the movement of the tools, while minimizing the parasitic forces, and thus to improve the quality and the consistency of the crimping.
• Another objective of the invention is to propose a presetting and crimping unit of simple design, of a low cost price, simple to implement and to maintain while working at high speed.
• the unit which is the subject of the invention is of the same general type as that described in document WO-A-93 05902, since it comprises two movable heads, one used for pre-crimping and the other for crimping, which are moved in synchronism to come one after the other press the edge of the sheet and get free, the movements of the two heads being controlled by a common motor shaft.
• the unit which is the subject of the invention is remarkable in that the crimping head describes, during pressing, a curvilinear trajectory whose instantaneous center of rotation is close to the bending zone of the sheet, and whose tangent at the end of crimping is substantially orthogonal to the plane of the sheet, the active face of the crimping head (which is applied against the sheet) remaining substantially parallel to herself during this move.
• This particular movement of the crimping tool allows working with regular and controlled quality, avoiding the formation of a ripple on the outer panel of the sheet, matrix side.
• the displacement of the presetting head takes place during pressing - and in particular at the end of pressing - in an orthogonal or substantially orthogonal direction to the plane of the sheet.
• the two heads are driven by a common drive shaft.
• the drive shaft of the unit according to the invention always rotates in the Same direction. Its movement is transmitted to the heads via an eccentric mechanism.
• the pre-crimping and crimping cycle corresponds to a full revolution of the motor shaft, and the stop precision at the end of the cycle does not matter, any interference between the movement transmission mechanisms and the heads moving being avoided.
• the motor shaft is rotated by an electric motor with incorporated speed reducer (gearmotor).
• gearmotor speed reducer
• the crimping head is mounted in the upper part of an approximately vertical oscillating arm, the lower end of which carries a first pin, by which it hinges on a link that can pivot freely around a fixed axis, while its middle portion carries a second pin hinged on a control lever.
• the presetting head is carried by an oscillating arm, approximately vertical, the lower end of which carries a first journal by which it is articulated on a rod which can pivot freely around a fixed axis, while its upper part carries a second pin hinged on a control lever.
• the plane of the sheet being substantially horizontal and the arms carrying the pre-crimping and crimping heads being both approximately vertical, the crimping head is located below the pre-crimping head.
• the subject of the invention is also a pre-crimping and crimping assembly for sheet metal, and in particular for very long sheet metal, this assembly being composed of several juxtaposed units such as that described above.
• At least some of said units have an angular positioning offset with respect to that of the others, the arrangement being such that the directions at the end of travel of the different presetting heads and of crimping are in all areas substantially orthogonal to the surface of the sheet.
• FIGS. 1 to 4 the pre-crimping and crimping tools have been given artificially simple shapes, and these two tools have been considered independently of each other, so as to allow a better understanding of their operation.
• the fixed elements are shown hatched.
• the reference 1 designates a piece to be crimped made up of two sheets 10 and 12, only the border zone of this piece which is the subject of the crimping operation having been shown.
• the part 1 is supported by a fixed matrix 14 whose support plane 15 is horizontal.
• This horizontal support plane will be conventionally called in the following description and in the claims "sheet plane".
• the lower sheet, which rests on the matrix 14, has a greater width than that of the other sheet 12; it has a flange 11 folded at right angles to the rest of the sheet, and therefore disposed vertically.
• the initial folding of the rim 11 was carried out using a separate tool, for example in a press. It is this rim 11 which must be folded back against the border zone 13 of the other sheet 12 in order to assemble the two sheets by crimping.
• the pre-crimping tool comprises a head 2 having a planar working face - or active face - 20, carried by a movable part formed by an arm 22 and an upper intermediate part 21.
• the arm 22 stands in a position near the vertical, slightly tilted outwards with respect to this vertical direction.
• the arm 21 carries a first pin 24, by which it is articulated to a link 4 articulated on a fixed axis 40, that is to say carried by the frame of the unit (not shown in Figures 1 to 4).
• the part 21 carries a second pin 23 by which it is articulated on a control lever 5, of approximately triangular shape.
• the latter pivots freely around a fixed axis 50, and carries a pin 51 by which it is articulated on a control rod 52.
• the rod 52 is curved, and its opposite end carries a pin 53 by which it is connected to the eccentric and connecting rod control mechanism, which will be described later.
• the pin 53 is subjected to a back-and-forth movement along an arc-of-circle trajectory, with center 530.
• the lower 4 and upper 52 links are arranged towards the outside (relative to the matrix 14).
• the points corresponding to the axes 23, 50, 40 and 24 constitute the angles of a fictitious deformable quadrilateral of which one of the sides is materialized by the part 21, 22 carrying the presetting head 2.
• the different axes are positioned, and the lever arms chosen, so that the movement of the active face 20 during the operation takes place in a substantially vertical direction, perpendicular to the plane 15.
• This face 20 is in a plane inclined at 45 ° relative to the plane 15, when it is at the end of the working stroke (FIG. 2).
• the preserting operation results from the upward movement of the pin 53 around the point 530 (arrow l 1 , figure 2), which causes the lever 5 to tilt downwards, around the point 50 (arrow I 2 ), and the deformation of the quadrilateral mentioned above.
• the lines L1 and L2 which respectively connect the points 23 and 50 on the one hand, and 24 and 40 on the other hand, are both parallel to the bearing face 15 (sheet metal plane), c 'that is to say horizontal ( Figure 2).
• the flange 11 once folded at 45 °, is referenced 11 '.
• FIG. 5A illustrates a presetting operation using a working head similar to that which has just been described, but whose working direction is not perpendicular to the plane of the sheet.
• This direction symbolized by the arrow E , is oblique with respect to the vertical, and breaks down into a vertical direction E 1 (orthogonal to the sheet metal plane) and horizontal E 2 (tangent to the sheet metal plane).
• the component E 2 has a parasitic effect, since it tends to excessively wind the rim 11 during its folding, the amplitude of the total winding being referenced i in FIG. 5A.
• the displacement of the head 2 takes place on the contrary in a purely vertical direction, perpendicular to the plane of the sheet, which reduces the winding amplitude, the latter corresponding to a value j very substantially less than i .
• the crimping tool shown schematically in Figures 3 and 4 includes a working head 3 which is carried by an approximately vertical arm 31 and has an active lower face - working face - 30 whose function is to press the edge partially folded 11 'to fold it completely and bring it into contact with the edge zone 13 of the sheet 12, so as to ensure complete crimping of the part 1.
• the arm 31 has, on the inner side, a middle portion 32 lying in overhang below the active face 30, substantially in line with the latter.
• the arm 31 is provided at its lower end with a first pin 33, by which it is articulated on a link 6 which can pivot freely around a fixed axis 60.
• the part 32 carries a second pin 34 by which it is articulated at the end of a lever 7. It is a slightly bent lever, the opposite end (outer side) of which carries a pin 70. This the latter is articulated on two rods 73, 74.
• the rod 73 approximately horizontal, can pivot freely around a fixed axis 730.
• the rod - or tie rod - 74 approximately vertical, extends upwards, and its end opposite (upper end) carries a pin 75.
• the pin 75 can follow a back-and-forth trajectory in an arc around the point 530 already mentioned with reference to FIGS. 1 and 2.
• the lever 7 In its central (angled) zone, the lever 7 carries a pin 71 articulated on a link 72 able to pivot freely around a fixed axis 720.
• the lever 7 and the link 6 are more or less horizontal, directed outwards.
• the rod 72 extends downward (relative to the lever 7), and it has an approximately vertical direction.
• the crimping tool 3 describes a complex movement, the trajectory of which is imposed by the semi-circular trajectories of the pins 70, 71 and 33 around the axes 730 , 720 and 60 respectively.
• the pin 75 is in the low position, which has the effect of keeping the head 3 tilted towards the outside, released relative to the part 1 (FIG. 3).
• this mechanism is arranged, and the various lever arms determined, in such a way that the active face 30 follows, as soon as it comes into contact with the sheet edge 11 ′, a trajectory curvilinear whose established center of rotation (in mobile position) is very close to the fold-back zone (apex of the bending angle) of the sheet, this face 30 moving further parallel to itself from the moment it came into contact with the sheet metal, until the end of the crimping.
• the tangent to this trajectory is, at the end of the race, normal to the sheet (perpendicular to face 15).
• points 730, 70 and 71 are almost aligned; point 71 progresses less and less quickly, while points 34 and 33 go down.
• the linkage produces a toggle effect which develops a very high pressing force during work.
• FIG. 6A shows a crimping head the pressing direction G of which is straight and oblique with respect to the plane 15 of the sheet; it breaks down into an orthogonal component G 1 and a tangential component G 2 . This generates, during the operation, a parasitic force which tends to move the part, which compromises the quality of the crimping.
• the crimping head 2 follows a curvilinear trajectory H centered at a point C (with variable position) located in the zone Z where the bending angle of prison. At the end of crimping, this trajectory is perpendicular to the surface 15.
• the crimped edge is referenced 11 ".
• the various fixed axes are carried by a frame 8, which also supports a motor shaft 90, driven in rotation - in a single direction symbolized by the arrow R - by means of an electric geared motor 9 .
• the shaft 90 is connected, by means of an eccentric crank pin, to the axis 910 of a connecting rod 91.
• the opposite end of the latter carries a journal 92 by which it is articulated to a lifting beam 93. This is pivotally mounted around the fixed axis 530 already mentioned.
• This lifter carries the pins 53 and 75 for driving the control rod 52 (of the pre-crimping tool) and the tie rod 74 (actuating the crimping tool), respectively.
• the lifter 93 In the cycle start position, favorable for removing the crimped part and for installing a new part, the lifter 93 is in an average angular position ensuring the clearances of the two heads 2 and 3 (FIG. 7 ).
• the lines M1 and M2 which connect, respectively, the points 34 and 71 on the one hand, and 33 and 60 on the other hand, are both parallel to the sheet metal plane 15, that is to say say horizontal (see Figure 4).
• the gearmotor and eccentric control allows pre-crimping and crimping in one complete revolution of the motor shaft. Unlike oscillating shaft systems (such as, in particular, that described in WO-93 05902), the stop precision at the end of the cycle therefore no longer matters, and has no effect on the quality and precision of work.
• the journal 92 which connects the eccentric connecting rod 91 to the lifter 93 is a frangible bar, capable of breaking (by shearing) if the transmission force exceeds a determined threshold. It is therefore calibrated to break if an exaggerated (and abnormal) effort is requested from the crankshaft. This is the case, for example, if a foreign body inadvertently interposed between the working heads and the piece to be crimped. This bar therefore has a safety role.
• backlash systems of a type known per se, are provided for each of the pre-crimping and crimping mechanisms.
• an eccentric backlash system mounted at the pin 53 which connects the lifter to the lever 52.
• a similar system can be provided at the pin 70 for example.
• a mark can be provided on the output shaft of the gearmotor, and two marks on the frame (one for pre-crimping, the other for crimping). Two reference faces are provided on the pre-crimping mechanism, and two reference faces are provided on the crimping mechanism.
• the backlash adjustment system is adjusted so that the distance measured between the reference faces of the pre-tightening mechanism reaches the desired value.
• the procedure is similar for crimping.
• the overhang of the crimping head 3 on its arm 31 is therefore reduced, and its working stroke has a relatively small amplitude, which makes it possible to develop a high compressive force during the crimping operation.
• the presetting head 2 has a higher overhang on its arm 21, and its working stroke is of greater amplitude. It acts on the part with a lower pressure than the crimping head.
• Such a unit can only work on a limited length of sheet metal.
• To treat a sheet of great length, and in particular its entire periphery it is possible to juxtapose a set of units such as that described above, which will be actuated jointly and in synchronism, to ensure crimping over a great length, by example over the entire perimeter of the sheet.
• a set of units such as that described above, which will be actuated jointly and in synchronism, to ensure crimping over a great length, by example over the entire perimeter of the sheet.
• the units are mounted in an adjustable manner on a frame.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Press Drives And Press Lines (AREA)
• Prostheses (AREA)

Applications Claiming Priority (2)

Publications (3)

Family

ID=9480010

Family Applications (1)

Country Status (4)

Cited By (4)

Families Citing this family (3)

Family Cites Families (5)

• 1995
  • 1995-06-09 FR FR9507113A patent/FR2735049B1/fr not_active Expired - Fee Related
• 1996
  • 1996-05-30 DE DE69616876T patent/DE69616876D1/de not_active Expired - Lifetime
  • 1996-05-30 ES ES96460021T patent/ES2166435T3/es not_active Expired - Lifetime
  • 1996-05-30 EP EP19960460021 patent/EP0747148B1/de not_active Expired - Lifetime

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