GB2081626A

GB2081626A - Edge bending of sheet metal workpieces

Info

Publication number: GB2081626A
Application number: GB8121354A
Authority: GB
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 1980-07-11
Filing date: 1981-07-10
Publication date: 1982-02-24
Also published as: JPS637381Y2; JPS5721427U; GB2081626B

Abstract

An edge bending machine for folding a pre-bent edge portion of a sheet metal workpiece a, around the edge of a metallic sheet b includes a workpiece receiving block 1, on which the sheets a and b are positioned with the surface which in the finished article is to be the outer surface facing upward and the prebent portion directed downwards. A clamp 2 is brought into contact with the upper surface of the sheet a adjacent the prebent portion and a bending punch 3 is brought into contact with the prebent portion exerting an upward and inward force on it thus bending it parallel to the upper surface of the sheet a. It is not necessary to turn the sheets a and b upside down between being conveyed to and from the bending machine and being bent by the bending machine to avoid damage to the outer surface of the sheet a. <IMAGE>

Description

SPECIFICATION Edge bending of sheet metal workpieces This invention relates to edge bending of sheet metal workpieces and is particularly concerned with a machine and a method for bending an edge portion of a sheet metal workpiece which has been prebent by a press machine into a certain required configuration. The invention is also particularly concerned with the case where the workpiece comprises two sheet metal portions one above the other which are to be connected by bending the edge of the upper outer portion around and edge of the lower portion.

It has been the usual practice in manufacturing large component parts of an automobile such as, for example, doors that, as shown in Figure 4 of the accompanying drawings, when an edge portion al of a sheet metal workpiece a which will constitute the outer surface of the part is to be folded inward to clamp the edge of an inner member b in the fold, the workpiece a is placed on a material positioning block 1 with its outer surface facing downward and its edge portion prebent upwardly, and then the inner member b is registered with the inner surface of the workpiece, after which the edge al of the workpiece a is folded inward to clamp the inner member 6.

When conveying the workpiece, before and after the edge is bent to its designated position on the bending machine, the workpiece is generally placed on a transfer device such as a belt conveyor, with its outer surface facing upwards to avoid any possible damage to its surface during conveying. It is therefore necessary that, before and after the bending operation in the bending machine, the workpiece be turned so that its upwardly facing outer surface be directed downwards to enable the bending operation to be effected properly. This additional operation of turning the workpiece upside down once and then again is not only troublesome, but may also cause damage to the external surface of the workpiece, should there be metal dust or the like on the workpiece receiving and mounting block.

It is thus an object of the present invention to provide a bending machine for a sheet metal workpiece which makes it possible to convey the workpiece to the bending machine with its outer surface facing upward, to fold the edge of the material at the working station in the bending machine in the orientation in which it was conveyed, and, after completion of the bending process, to convey it away in the same orientation, thereby avoiding any wasteful operation in turning the workpiece upside down before and after every bending operation and preventing the occurrence of damage to its outer surface.

According to the present invention there is provided an edge bending machine for bending the edge of a sheet metal workpiece, which includes a receiving block to receive and support a sheet metal workpiece conveyed thereonto with its outer surface facing upwards, and with the edge portion partly bent and extending downwards, a bending die movably mounted to contact the outer surface of the workpiece adjacent the edge portion to be bent of the sheet metal workpiece on the receiving block and a bending punch movably mounted to engage the partly bent edge portion of the workpiece to exert an upward and inward force thereon to bend it substantially parallel to the outer surface of the sheet metal workpiece.

Thus the workpiece may be conveyed with its outer surface upwards as before and then placed on the receiving block in the same orientation with the prebent edge of the workpiece, which is preferably prebent through about 900, beyond the edge of the receiving block and extending downwards. This in then bent through the further 900, either into contact with the undersurface of the sheet metal portion of which it forms part or into contact with a second sheet metal portion thus gripping the latter, and the workpiece is then conveyed away in the same orientation.

In one embodiment the bending die, which exerts a reactive force against that exerted by the bending punch, is carried on a first pivotally mounted arm which is connected to a fixed member situated adjacent the receiving block and which may be rotated to bring the bending die into contact with the outer surface of the workpiece from above. A further embodiment includes a movable block which carries the bending die and is mounted on a fixed table having an upper surface which is downwardly inclined towards the receiving block, whereby when the movable block is moved on the inclined surface towards the receiving block the bending die is brought into contact with the outer surface of the workpiece.

Preferably the bending punch is carried on a second pivotally mounted arm which may be rotated to bring the bending punch into contact with the edge portion of the workpiece from below to bend it. The second pivotally mounted arm may be mounted to rotate about a fixed axis situated below the receiving block or it may be mounted on the movable block.

The invention also embraces a method of bending the edge of a sheet metal workpiece which includes conveying the workpiece with its outer surface upwards onto a receiving block with the edge partly bent and extending downwards, bringing a bending die into contact with the upper surface of the workpiece adjacent the edge portion, bringing a bending punch into engagement with the partly bent edge portion from below and exerting thereby an upward and inward force to bend it substantially parallel to the outer surface of the workpiece. The workpiece may be a single sheet of metal or it may include two sheet metal portions one above the other which are to be connected by bending the edge of the upper outer portion around an edge of the lower portion.

Further features and details of the invention will be apparent from the following description of two specific embodiments which is given by way of example with reference to the accompanying diagrammatic drawings in which Figure 1 is a fragmentary side elevation showing a sheet metal workpiece after having been folded inward to clamp an inner member by an edge bending machine according to the present invention; Figure 2 is a side elevation of one embodiment of an edge bending machine according to the present invention; Figure 3 is a view similar to Figure 2 of a modified embodiment of edge bending machine according to the present invention; and Figure 5 is a fragmentary elevation, partly in section, illustrating the bending of the edge of a sheet metal workpiece by a machine according to the present invention.

The embodiments of both Figures 2 and 3 include a block 1 for receiving and mounting thereon a workpiece. The block 1 is supported on a stand 4 fixedly mounted on a base F, and includes at one end a stopper or abutment 5 for positioning the workpiece (which in the illustrated embodiment is an inner sheet metal member b which is to be connected to an outer sheet metal member a). The block 1 has an irregular upper surface 6 whose shape corresponds to that of the workpiece.

In the embodiment of Figure 2, a fixed stand 7 is disposed adjacent the block 1 on the base F at the upper portion of which an oscillating arm 8 carrying a bending die 2 is pivotally mounted on a shaft 9. The bending die 2 is secured at one end of the oscillating arm 8 so as to cooperate with the workpiece. A telescopic actuating mechanism 10 of hydraulic, pneumatic or electromagnetic type is connected to the lower part of the fixed stand 7 and to the other end of the oscillating arm 8. The connection is effected by means of a pivot 16 which allows the actuator 10 to perform the necessary pivotal motion when being extended or retracted.

A bending punch 3 is connected to one end of a cranked oscillating arm which is mounted on the fixed stand 7 by means of a pivotal shaft 12 situated below the block 1. The bending punch 3 is thus below the sheet metal workpiece to be folded whilst the other end of the oscillating arm 11 is connected to a telescopic actuating mechanism 13 which, in turn, is fixedly secured to the base F by means of a support 14 which is pivotally connected at 15 to the mechanism 13 to permit the latter to perform the necessary pivotal motion when being extended or retracted.

In use, the bending die 2 on the oscillating arm 8 is lifted upward away from the block 1 to the position shown in chain-dotted lines by retracting the piston rod of the actuating mechanism 10. The bending punch 3 and the oscillating arm 11 carrying it are similarly withdrawn from the block 1 to a position shown by hard lines in the drawing by retracting the piston rod of the actuating mechanism 13. Two sheet metal workpieces a and b are then conveyed to the workpiece receiving and mounting block 1 by conveying means (not shown) and positioned thereon. The outer surface of the workpiece a is to be the outer surface of the connected unit and this is directed upwardly.The workpieces a and b are retained in their desired relative positions by means of an edge portion a 1 ' of the workpiece a which is bent at right angles to the remainder of the workpiece a and directed downwardly prior to being placed on the block 1.

Subsequently, the actuating mechanism 10 is extended to move the arm 8 to the position shown in hard lines thus causing the bending die 2 to contact the outer surface of the workpiece a which projects beyond the edge of the block 1. The actuating mechanism 10 may be operated by, foP example, a sequence control apparatus which produces a sequence control signal to initiate each operationai step of the machine. When movement of the arm 8 is finished an operation completion signal from the sequence control apparatus initiates actuation of the actuating mechanism 13, whereby the oscillating arm 1 1 is rotated on the shaft 12 toward the half-bent edge al' of the workpiece a into the position shown by the chaindotted line.The bending punch 3 at one end of the oscillating arm 11 engages the portion al' at an angle to exert a lateral and upward punching force to the edge portion al' to effect folding of that portion from the position shown in dotted lines to that shown by a solid line and designated al in Figure 1 against the reactive force exerted by the die 2. In this case, the workpiece receiving and mounting block 1 is so disposed that the outer surface of the workpiece a placed thereon is in flat, horizontal contact with the die 2. The top surface of the bending punch 3 where it contacts the half-bent edge of the workpiece a is inclined at such an angle that it acts on the edge portion to ultimately fold the same substantially parallel to the outer surface of the workpiece a.

Figure 3 illustrates a modified embodiment in which both the bending die 2 and the bending punch 3 are differently mounted. In this embodiment, the bending die 2 is provided at one end of an obliquely movable block 18 which can slide on one or more inclined guide rails 20 situated on a table 19. The table 19 is secured to the base F and the rails 20 are slightly downwardly inclined towards the block 1. The movable block 18 is connected to the piston rod of a telescopic actuating mechanism 17, actuation of which causes movement of the block 18 on the rails 20 between the position shown in hard lines in which the bending die 2 engages the workpiece a and the position shown in chain-dotted lines in which the bending die is above and to the left (as seen in Figure 3) of the workpiece a but its engagement surface is still parallel to the upper surface of the workpiece a.

The oscillating arm 21 carrying the bending punch 3 is pivotally connected at one end to the movable table 18 by means of a shaft 22 and is moved by a telescopic actuating mechanism 23 which is connected to another part of the movable block 18 and whose piston rod is connected to an intermediate portion of the arm 21.

In use, the actuating mechanisms 17 and 23 are extended and retracted respectively to move the table 18 and arm 21 to the positions shown in chain-dotted lines. The workpieces a and b are placed in position and the piston rod of the actuating mechanism is retracted so that the movable block 18 slides downward along the guide rail 20 until the bending die 2 engages the outer surface of the sheet metal workpiece a. As soon as the bending die 2 contacts the workpiece a, the telescopic drive mechanism 23 is actuated to extend its piston rod to cause the arm 21 to rotate about the pivotal shaft 22 to raise the arm 21 to engage the half-bent edge a 1' of the workpiece a to exert an upward and inward force against the reactive force exerted by the die 2.

Thus the bending punch 3 at the forward end of the oscillating arm 21 applies a punching force to the edge portion al' to bend that portion in a manner similar to that described in connection with Figures 1 and 2.

In the embodiment shown in Figure 2, the punching force is applied to the edge portion al' which was already bent at right angles by movement of the bending punch 3 which is rotated clockwise by means of the actuating mechanism 13 about the pivot 12 toward the half-bent edge of the workpiece a to contact it from below to exert an upward and inward force.

In the embodiment shown in Figure 3, the punching force is applied to the edge portion al' by movement of the bending punch 3 on the oscillating arm 21 which is rotated counterclockwise about the pivot 22 by the actuating mechanism 23 toward the downwardly bent edge portion al' of the workpiece a to contact it from below to push it upwards and inwards to fold it through the full 1800.

In the apparatus of the present invention the outer surface of the workpiece is kept facing upward during its conveyance and in this orientation it is engaged from above by the bending die, and the oblique punching force is applied to it from below to bend it upwardly and inwardly to a position substantially parallel with the outer surface. The working efficiency is thus extremely high and the occurrence of damage to the outer surface of the workpiece can be effectively prevented since no transfer of the workpiece between the conveying orientation and the bending orientation is required.

Claims

1. An edge bending machine for bending the edge of a sheet metal workpiece, which includes a receiving block to receive and support a sheet metal workpiece conveyed thereonto with its outer surface facing upwards, and with the edge portion partly bent and extending downwards, a bending die movably mounted to contact the outer surface of the workpiece adjacent the edge portion to be bent of the sheet metal workpiece on the receiving block and a bending punch movably mounted to engage the partly bent edge portion of the workpiece to exert an upward and inward force thereon to bend it substantially parallel to the outer surface of the sheet metal workpiece.

2. A machine as claimed in Claim 1 in which the bending die is carried on a first pivotally mounted arm which is connected to a fixed member situated adjacent the receiving block and which may be rotated to bring the bending die into contact with the outer surface of the workpiece from above.

3. A machine as claimed in Claim 1 including a movable block which carries the bending die and is mounted on a fixed table having an upper surface which is downwardly inclined towards the receiving block, whereby when the movable block is moved on the inclined surface towards the receiving block the bending die is brought into contact with the outer surface of the workpiece.

4. A machine as claimed in any one of the preceding claims in which the bending punch is carried on a second pivotally mounted arm which may be rotated to bring the bending punch into contact with the edge portion of the workpiece from below to bend it.

5. A machine as claimed in Claim 4 when dependent on Claim 1 or Claim 2 in which the second pivotally mounted arm is mounted to rotate about a fixed axis situated below the receiving block.

6. A machine as claimed in Claim 4 and Claim 3 in which the second pivotally mounted arm is mounted on the movable block.

7. An edge bending machine for bending the edge of a sheet metal workpiece substantially as specifically described herein with reference to Figures 1 and 2 or Figures 1 and 3 of the accompanying drawings alone or in combination with Figure 5.

8. A method of bending the edge of a sheet metal workpiece which includes conveying the workpiece with its outer surface upwards onto a receiving block with the edge partly bent and extending downwards, bringing a bending die into contact with the upper surface of the workpiece adjacent the edge portion, bringing a bending punch into engagement with the partly bent edge portion from below and exerting thereby an upward and inward force to bend it substantially parallel to the outer surface of the workpiece.

9. A method as claimed in Claim 8 in which the workpiece includes two sheet metal portions one above the other which are to be connected by bending the edge of the upper outer portion around an edge of the lower portion.

10. A method of bending the edge of a sheet metal workpiece substantially as specifically herein described with reference to Figures 1 and 2 or Figures 1 and 3 of the accompanying drawings alone or in combination with Figure 5.