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Patent Searching and Data


Title:
BENDING APPARATUS
Document Type and Number:
WIPO Patent Application WO/1992/011956
Kind Code:
A1
Abstract:
The invention relates to an apparatus for bending an edge flange (4) which projects out at an angle to a surface of a workpiece (3) in towards said workpiece. The apparatus includes a bending tool (5) which is mounted on a tool holder (21) which, by means of a linkage mechanism (13, 17, 18) is moveably connected to a stand (1) which is attached to a foundation surface (2) on which the workpiece (3) is supported. A drive means (30) mounted on the stand is connected to the tool holder (21) in a manner to drive the same and thereby also the tool (5). According to the invention, the linkage mechanism between the tool holder (21) and the stand (1) is comprised of two parallel links (17, 18) and a triangular link (13). One end of each of the parallel links (17, 18) is pivotally connected to the tool holder (21) and the other end of the parallel links is pivotally connected to the triangular link (13), this triangular link also being pivotally connected to the stand (1). The parallel links (17, 18) form together with the tool holder (21) and the triangular link (13) a parallelogram linkage mechanism. A guide means (22-28) is provided for guiding the movement of the parallel links (17, 18) and the triangular link (13). The drive means (30) is connected to one (18) of the parallel links (17, 18) for driving of the tool holder (21) and the tool (5) through the intermediary of this one link.

Inventors:
MALMGREN BO (SE)
DORSETT MICHAEL (GB)
Application Number:
PCT/SE1991/000828
Publication Date:
July 23, 1992
Filing Date:
December 04, 1991
Export Citation:
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Assignee:
VOLVO AB (SE)
International Classes:
B21D19/08; B21D39/02; (IPC1-7): B21D5/16
Domestic Patent References:
WO1989009102A11989-10-05
Foreign References:
US4346579A1982-08-31
Download PDF:
Claims:
Claims
1. An apparatus for bending an edge flange (4) which projects out from a workpiece (3) in towards said work piece, said apparatus including a bending tool (5) which is mounted on a tool holder (21) which is moveably connected to a stand (1) by means of a linkage mechanism (13, 17, 18), said stand being secured to a foundation surface (2) on which the workpiece (3) is supported, said apparatus further including drive means (30) mount¬ ed on the stand and connected to the tool holder (21) such as to drive said tool holder and therewith the tool (5), c h a r a c t e r i z e d in that the linkage mechanism between the tool holder (21) and the stand (1) is comprised of two parallel links (17, 18) and a trian¬ gular link (13) , wherein one end of each of said paral¬ lel links (17, 18) is pivotally connected to the tool holder (21) and the other end of each said parallel links is pivotally connected to the triangular link (13) which is also pivotally connected to the stand (1) ; in that the parallel links (17, 18) together with the tool holder (21) and the triangular link (13) form a paral¬ lelogram linkage mechanism; in that a guide means (22 28) is provided for guiding movement of the parallel links (17, 18) and the triangular link (13); and in that the drive means (30) is connected to one (18) of the i parallel links (17, 18) such as to drive the tool holder (21) and the tool (5) through the intermediary of said one link.
2. An apparatus according to Claim l, c h a r a c t e¬ r i z e d in that the guide means includes a guide roller (22) on one (18) of the parallel links (17, 18) and a guide plate (25) on the stand (1) , said guide plate (25) having a recess (26) with side surfaces (27, 28) for coaction with the guide roller (22) .
3. An apparatus according to Claim 1 or 2, c h a r a c t e r i z e d in that a projection (34) and a coacting stop surface (35) are arranged respectively on the triangular link (13) and the stand (1) such as to restrict movement of the triangular link (13) in relation to the stand (1) .
4. An apparatus according to any one of Claims 13, c h a r a c t e r i z e d in that the drive means is a pressuremedium pistoncylinder device (30) which is pivotally connected to the stand (1) and has a piston rod (31) which is pivotally connected to one (18) of said parallel links (17, 18).
5. An apparatus according to any one of Claims 14, c h a r a c t e r i z e d in that the stand includes a bottom plate (6) which is attached to the foundation surface (2) , and a main part (8) which is pivotally connected to said bottom plate; and in that an exchange able spacer device (10, 36) is mounted between the bottom plate (6) and the main part (8) such as to hold these components in a predetermined mutual angular position.
Description:
Bending Apparatus

The present invention relates to apparatus for bending an edge flange which projects out at an angle to a surface of a workpiece inwardly towards said workpiece, said apparatus comprising a bending tool mounted on a tool holder which is moveably connected by means of a linkage mechanism to a frame which is fixedly mounted to a foundation surface and on which the workpiece is supported, and further comprising drive means mounted on the frame and connected to the tool holder such as to drive said tool holder and therewith the tool.

Apparatus of this kind are known to the art and may have mutually different constructions. Such an apparatus may be used, for example, to bend an edge flange of a plate inwardly around the edge of another plate, such as to provide some form of hem which connects the two plates together. This type of operation is normal, for in¬ stance, in the car industry in the manufacture of dif¬ ferent body parts. In this case, the space around the edge flange to be folded-in is often very restricted. The earlier known apparatus, however, reguires a rela- tively large amount of free space in order to function satisfactorily, which means that these known apparatus can only carry out work of this type with great diffi¬ culty, if at all.

The object of the present invention is to provide an apparatus of the kind described in the introduction with which the described drawbacks of earlier known apparatus are avoided and which can be also used to bend work- pieces in confined spaces with satisfactory results. This object is achieved in accordance with the invention in that the linkage mechanism between the tool holder

and the frame is comprised of two parallel links and a triangular link, wherein one end of each of said paral¬ lel links is pivotally connected to the tool holder and the other ends of respective parallel links are pivotal- ly connected to the triangular link, which is also pivotally connected to the stand,* in that the parallel links together with the tool holder and the triangular link form a parallelogram linkage mechanism; in that guide means are provided for guiding the movement of the parallel links and the triangular link; and in that said drive means is connected to one of the parallel links such as to drive the tool holder and the tool through the intermediary of said one link.

The invention will now be described in more detail with reference to the accompanying drawings, in which

Figure l is a somewhat schematic side view of a bending apparatus according to one embodiment of the invention; Figure 2 is a schematic side view of the apparatus shown in Figure 1, and shows the starting position of the apparatus prior to commencing a working sequence; Figure 3 is a schematic side view of the apparatus shown in Figure 1, and illustrates the apparatus in an inter- mediate position during a working sequence;

Figure 4 is a schematic side view of the apparatus shown in Figure 1, and shows the apparatus in a bend-completed position during a working sequence; and Figure 5 is a schematic side view of an inventive bend- ing apparatus with modified mounting in relation to a supporting foundation.

The inventive bending apparatus illustrated in the drawings includes a stand 1 which is mounted on a foundation surface 2, which is only shown schematically in the drawings. Another part of the foundation surface

2 supports a workpiece 3, which is again only shown schematically and which includes an edge flange 4 which in the starting position shown in Figure 2 projects out at an angle to that part of the workpiece 3 which lies on the foundation surface 2. The edge flange 4 is to be bent inwards to a final state or position with the aid of the bending apparatus, as illustrated in Figure 1, which shows the edge flange 4 generally parallel with the part of the workpiece 3 resting on the foundation surface 2. This inward bending of the edge flange is effected with the aid of a bending tool 5.

The stand 1 includes a bottom plate 6 which is attached to the foundation surface 2 with the aid of screws 7, of which only one is shown in Figure 1, and also a pivotal main part 8 which is pivotally journalled to the bottom plate 6 by means of a pivot shaft 9. Figure 1 shows the main part 8 in abutment with the bottom plate 6 through the intermediary of a spacer plate 10, which is screwed firmly to the bottom plate 6 with screws 11, of which only one is shown in Figure 1, and to which the pivotal main part 8 is firmly screwed with screws 12, of which only one is shown in Figure 1.

A triangular link 13 is pivotally mounted on the main part 8 of the stand 1 by means of a pivot shaft 14. In this case, the fehaft 14 is positioned substantially at one corner of the triangular link 13, whereas a respec¬ tive shaft 15 and 16 is mounted in the vicinity of each of the two remaining corners of the triangular link 13.

One end of a link 17 is pivotally mounted on the shaft 15, while one end of a further link 18 is pivotally mounted on the shaft 16. The opposite end of each of said links 17, 18 is pivotally mounted on a tool holder 21 by means of a respective pivot shaft 19 and 20, said

tool holder 21 carrying the tool 5. The distance be¬ tween the pivot shafts 15 and 16 is equal to the dis¬ tance between the pivot shafts 19 and 20, and the dis¬ tance between the pivot shafts 15 and 19 is equal to the distance between the pivot shafts 16 and 20. Thus, the links 17 and 18 and those parts of the triangular link 13 and the tool holder 21 connected thereto form a parallelogram linkage mechanism which connects the triangular link 13 and the tool holder 21.

A guide roller 22 is rotatably journalled on a shaft 23 on a projection 24 which extends out from the link 18 on the side of the shaft 16 remote from the shaft 20. The guide roller 22 coacts with a guide plate 25 which is attached to the main part 8 of the stand 1 and is pro¬ vided with a recess 26 in which the guide roller 22 is located. The recess 26 is open towards the link 18 and is defined by a generally straight side surface 27 and a contoured side surface 28. The contoured side surface 28 has a first part 28a which is substantially straight and parallel with the straight side surface 27, and a second part 28b which forms part of a cylindrical sur¬ face whose centre coincides with the centre of the pivot shaft 16. The distance between the straight side sur- face 27 and the first part 28a of the contoured side surface 28 is somewhat larger than the diameter of the guide roller 22, and the second part 28b has a radius such that the guide roller 22 is able to roll along said part when the link 18 is pivoted on the pivot shaft 16.

The main part 8 of the stand 1 also carries, by means of pins 29, a drive means 30 in the form of a pressure medium cylinder, for example a hydraulic piston-cylinder device. This device is pivotal on the shafts 29. The piston-cylinder device 30 has a piston rod 31 which is provided on its free, outer end with an end piece 32

which is pivotally connected to the link 18 by means of a pivot shaft 33.

The triangular link 13 is also provided with a projec¬ tion 34 which is intended to coact with a stop surface 35 on the main part 8 of said stand so as to restrict pivotal movement of the triangular link 13 on the shaft 14 when the piston rod 31 of the piston-cylinder device 30 is extended.

The method of operation of the described apparatus will be best seen from Figures 2-4. Figure 2 illustrates the starting position. In this position, the piston rod 31 of the piston-cylinder device 30 is fully retracted. When the piston rod 31 is retracted, the link 18 will swing clockwise in relation to the triangular link 13 until the guide roller 22 comes into contact with the straight side surface 27. Continued retraction of the piston rod 31 will then cause the triangular link 13 to swing clockwise on the shaft 14, so as to lift the projection 34 on the triangular link 13 away from the abutment surface 35 on the main part 8 of the stand 1. In this stage, the guide roller 22 is located in the lower part of the recess 26, i.e. between the straight side surface 27 and the first straight part 28a of the side surface 28. The tool holder 21 and the bending tool 5 have therewith been moved away from the workpiece 3 to an extent which is sufficient to enable a workpiece exchange to be made unobstructed.

Subsequent to placing a new workpiece 3 correctly on the foundation surface 2 as shown in Figure 2, i.e. with the edge flange 4 upstanding, the drive means, i.e. the piston-cylinder device 30, is activated so as to extend the piston rod 31. As the piston rod 31 is extended, it will act on the link 16 and move said link, and also the

tool holder 21 with bending tool 5, the link 17 and the triangular link 13, to the left as seen in the Figure. The triangular link 13 will then, of course, swing around the shaft 14, whereas movement of the link 18 is guided by coaction between the guide roller 22 and the recess 26 in the guide plate 25.

The guide roller 22 is now located in the lower part of the recess 26, between the straight side wall 27 and the first part 28a of the contoured side wall 28. The roller 22 is now essentially only capable of moving straight upwards. Pivotal movement of the triangular link 13 around the shaft 14 is restricted by contact of the projection 34 on the triangular link 13 with the stop surface 35 on the main part 8 of the stand 1. This is evident from Figure 3, which illustrates an interme¬ diate operational stage in which the guide roller 22 is located at the junction between the parts 28a and 28b on the contoured side surface 28.

Continued extension of the piston rod 31 of the piston- cylinder device 30 causes the links 27 and 18 to swing in an anticlockwise direction around the respective shafts 15 and 16, so as to move the tool holder 21 and the bending tool 5 towards the workpiece 3. The bending tool 5 is therewith moved into engagement with the edge flange 4 which, as the bending tool 5 continues to move, is bent inwardly to the final position shown in Figure 4. With this final movement, the guide roller 22 moves along the second part 28b of the contoured side surface 28 in the recess 26. The projection 34 on the triangu¬ lar link 13 therewith abuts the abutment surface 35 on the main part 8 of the stand 1. The final operational stage shown in Figure 4 is also the stage shown in Figure 1.

Retraction of the piston rod 31 into the cylinder of the device 30 causes the various components to move in directions opposite to those aforedescribed. Thus, the links 17 and 18 will initially swing around respective shafts 15 and 16, the guide roller 22 moving along the second part 28b of the side surface 28. When the guide roller 22 passes the junction between the second part 28b and the first part 28a of the side surface 28, the triangular link 13 will begin to swing clockwise around the shaft 14, whereafter continued retraction of the piston rod 11 will cause the triangular link 13 to swing around the shaft 14. At the same time, the guide roller 22 is moved into the lower part of the recess 26, where said roller is guided between the side surface 27 and the first part 28a of the side surface 28. The movement continues until the various components have been re¬ turned to the starting position shown in Figure 2.

Figure 5 illustrates an inventive bending apparatus which corresponds to the apparatus illustrated in Figure 1 , with the exception that the spacer plate 10 has been replaced with an angled bracket 36. The bracket 36 is secured to the bottom plate 6 by means of screws 11, of which only one is shown in the drawing, and the main part 8 of the stand 1 is secured to the upper end of the bracket 38 by means of screws 12, of which only one is shown in the drawing. As shown in Figure 5, the main part 8 has been swung around the shaft 9 to another vertical position in relation to the bottom plate 6, this angular position being determined by the bracket 36. By exchanging the angled bracket 36 with another angled bracket of different dimensions, it is thus possible to position the main part 8 in a desired angu¬ lar position in relation to the bottom plate 6 so as to adapt the alignment of the bending tool 5 to the pre¬ vailing position of the workpiece 3. The method of

operation, of the bending apparatus shown in Figure 5 fully corresponds with the method of operation of the apparatus described with reference to Figures 1-4.

It will be understood that the invention is not restric¬ ted to the aforedescribed embodiments thereof and that changes and modifications can be made within the scope of the following Claims.