GB2071541A - Improvements in bending brakes - Google Patents

Abstract

In a sheet bending brake in which a workpiece (S) is clamped between an anvil surface on a rail portion (20) and a clamping member (21), an extension member (40) is secured to the clamping member and has a forward extension (43) so that the workpiece can be bent through more than 90 DEG and approaching 180 DEG by swining a bending member (18). A spring-loaded floatable compensator (22) is pivoted to the bending member and is adapted to engage the workpiece being bent. <IMAGE>

Description

SPECIFICATION Improvements in bending brakes This invention relates to sheet bending brakes.

In United States Patents Nos. 3,161,223, 3,481,174, 3,482,427, 3,559,444,3,817,075 and 3,872,755, there are described sheet bending brakes for bending metal or plastics sheets as are used in sliding or cladding on homes and buildings.

An object of this invention is to provide an improved sheet bending brake which permits the forming of a bend through substantially greater than ninety degrees.

In accordance with the invention, a sheet bending brake has a fixed jaw a movable jaw, said fixed jaw having an anvil surface thereon and said movable jaw having a clamping surface movable between workpiece clamping and non-clamping positions relative to the anvil surface, means for releasably locking the movable jaw in work piece clamping position, a bending member hingedly connected to the fixed jaw, said movable jaw having its front edge spaced rearwardly of the front edge of said anvil surface when in clamping position, an extension member mounted on said front edge of said movable jaw and having a portion extending forwardly and forming an extension of the clamping surface, the region above said portion of said extension member being free and unobstructed such that the workpiece can be bent substantially beyond 900.

The invention is further described, by way of example, with reference to the drawings, in which: Fig. 1 is a fragmentary part sectional side elevational view of a sheet bending brake embodying the invention; Fig. 2 is a larger scale fragmentary part sectional view similar to Fig. 1 showing the parts in a different operative position; Figs. 3 and 4 are diagrams of the types of bent shapes that can be made utilizing the sheet bending brake embodying the invention; Fig. 5 is a fragmentary end elevational view of a modified form of sheet bending brake; and Figs. 6 and 7 are fragmentary views showing the action of the several components during bending of a workpiece.

The brake embodying the inventin comprises longitudinally spaced C-shaped frame members 10 interconnected by a front rail 11 and a rear rail 12. Each frame member 10 includes a lower arm 13a which is designed to define a front side face recess 14 to which rail 11 is bolted as by bolts 1 5 and a rear side face recess 16 to which shaped rail 12 is bolted as by bolts 17. Each C-frame member 10 also includes an upper arm 13b which overlies the lower arm 13a in spaced relation thereto. Tubular legs L extend into integral sockets in some of frames 10 to support the brake above the floor. A bending member 18 in the form of an aluminum extrusion having generally the shape of the numeral 6 is hinged to front rail 11 and one or more bending bar handle members 19 are fixed to the bending bar 18 for facilitating movement thereof.The upper portion 20 of front rail 11 is formed with a flat anvil surface.

Portion 20 and bending member 18 are formed with mating integral projections along their longitudinal edges, which projections are provided with openings coaxially aligned when the projections are intermeshed and a pin extends through the openings to complete the hinge between bending member 18 and portion 20.

A clamping member 21 is provided in overlying relation to the upper planar an#vil surface of portion 20.

A generally L-shaped floating hinge compensator 22 is provided in overlying relation to the upper planar surface of bending member 18 and is pivotally secured thereto by engagement with a groove in bending member 18. Springs 23 are interposed between a lip 24 and compensator 22.

Hinge compensator 22 is provided along its or outermost longitudinal edge with a foot portion 25 which normally overlies and rests against the outwardly facing surface defined by the hinge connection between the bending member 18 and the portion 20.

As shown in Fig. 1, when the bending member 1 8 is out of bending position, the foot portion 25 of the hinge compensator 22 overlies the hinge connection and is disposed in a horizontal plane below that of the clamping member 21.

As the bending member 18 is swung upwardly from the position shown in Fig. 1 to the position shown in Fig. 2, the compensator 22 pivots with foot portion 25 thereof riding upwardly relative to the lower planar surface of the workpiece, which is clamped relative to the member 21 by a clamping sub-assembly presently described.

When the workpiece has been bent to the desired angular shape, the bending member 18 is swung downwardly whereupon the foot portion 25 of the compensator 22 rides downwardly to return to its normal position wherein it overlies the hinge connection.

The clamping sub-assembly includes a channelshaped pivot bar 26 on each frame 10 on which anvil 21 is fixed. Bar 26 is pivoted at its opposite innermost end to upper arm 13b of each C-frame l0asbyapivotpin27.

A handle member 28 is pivoted along one of its edges by a pivot pin 29 to the forward end of upper arm 13b of each C-frame 10 and is pivotally connected to pivot bar 26 by a spring member 30 pivoted at its upper end to an edge of the handle member and at its lower end to the pivot bar 26.

A tension spring 31 is connected at one end to upper arm 13b and at its opposite end to pivot bar 26 to yieldingly urge each bar 26 upwardly.

Each spring 30 is made of metal as by extrusion and is generally oval shaped in cross section including a front wall 32, rear wall portions 33 extending toward one another with a space therebetween. A wedge 34 extends into the space and a screw 35 extends through front wall 32 and is threaded into the wedge 34. By threading screw 35 inwardly and outwardly, the spring force of spring member 30 can be varied.

Spring member 30 is formed with an opening 36 at its upper end through which a pin 37 is positioned and extends into an opening in handle member 28 to pivot spring member 30 to the handle member 28. A clip 38 having spaced arms extends through an opening in bar 26 and telescopes over the lower end of spring member 30 to pivot the spring member 30 to bar 26.

Manipulation of handle member 28 clockwise as viewed in Fig. 1 forces member 21 downwardly to clamp a sheet S to be bent on portion 20.

During this movement, the spring member 30 is moved so that its pivot passes under pivot 29 applying a resilient clamping force on member 21.

A bolt 44 is adjustably threaded horizontally into the upper arm forming an adjustable stop which is engaged by spring member 30 to control the locked position of the spring 30.

The clamping member 21 has its forward edge spaced rearwardly of the forward edge of the portion 20 when the member 21 is in clamping position. An extension member 40 is mounted on the member 21. Extension member 40 is made of uniformly thick material and comprises a first portion 41 received in a vertical slot in the inner surface of member 21, a second portion 42 extending along the inclined inner surface of member 21 and a horizontal portion 43 extending along the bottom surface of member 21 to define a free bending edge. Fasteners 43' extend through second portion 42 at longitudinally spaced points and are threaded into the member 21.

In use, a sheet S is properly positioned relative to lower arm 13a so that it rests upon portion 20 and foot portion 25 of hinge compensator 22.

Handle member 28 is then swung downwardly to bring the clamping surface of extension member 40 into contact with the upper planar surface of the sheet S and the handle member 28 is rotated to swing spring member 30 past centre, thereby locking the clamping member 21 on the sheet S.

Bending bar handle member 19 is now swung upwardly to cause the foot portion 25 of the compensator 22 to pivot upwardly relative to bending member 18 thereby causing the workpiece to bend along the forward edges of the extension member.

Since the horizontal portion 43 of extension member 40 extends beyond the forward edge of member 21 and the area above the portion which extends beyond the member 21 is unobstructed, the bending member 18 can be swung substantially beyond ninety degrees producing a bend substantially greater than ninety degrees up to substantially 1 800 (Fig. 2).

When the sheet S has been bent to the desired angle, the handle member is swung downwardly and the compensator 22 returns to its rest position.

The types of sheet shapes that can be formed on the sheet metal brake embodying the invention are shown in Figs. 3 and 4 wherein portions are bent at 1 800 so that hemmed assemblies can be made.

In the form of the invention shown in FIGS.

5-7, clamping member 154 has its forward edge spaced rearwardly of the forward edge of anvil plate 138 when the anvil plate 138 is in its forward position and the clamping member 154 is in clamping position. An extension member 158 having an L-shaped cross section is fastened to the front end of clamping member 1 54 by fasteners such as screws along the vertical leg thereof. The horizontal leg 1 59 of the extension member 158 has its lower surface coplanar with the underside of the clamping member 154 to form an extension of the clamping surface. The area above the horizontal leg 159 is unobstructed so that handle member 134 can be swung substantially beyond 900 to bend the workpiece over into lose proximity with the upper surface of the horizontal leg 159 of extension member 158.

In use, a workpiece is properly positioned relative to lower arm 11 6 so that it rests upon anvil member 138 and foot portion 150 of hinge compensator 144, the anvil member first having been positioned according to the presence or absence of a pre-bent portion in the workpiece.

Handle member 166 is now swung downwardly to bring clamping surface 1 56 of clamping member 154 into contact with the upper planar surface of the workpiece and the handle member is rotated to bring the head 1 86 of screw 188 into contact with the head of the locking bolt 184 provided in locking block 178, thereby effectively locking the clamping sub-assembly relative to the workpiece and anvil member.

Bending bar handle member 134 is now swung upwardly to cause the foot portion 1 50 of the compensator 144 to pivot upwardly relative to bending bar 132 thereby causing the workpiece to bend along the forward edges of the anvil plate and clamping member.

When the workpiece has been bent to the desired angle, the handle member is swung downwardly and the compensator 144 returns to its rest position.

Since the horizontal leg 159 of extension member 158 extends beyond the anvil and the area above the free edge is unobstructed, the bending member can be swung substantially beyond 900 causing the compensator 144 to produce a bend substantially greater than 900 and substantially as great as 1 800.

It is possible to produce substantially 1 800 bends along the workpiece permitting great flexibility in shaping the workpiece for use, for example, in trimming windows.

Claims (8)

1. A sheet bending brake comprising a frame having a fixed jaw a movable jaw, said fixed jaw having an anvil surface thereon and said movable jaw having a clamping surface movable between workpiece clamping and non-clamping positions relative to the anvil surface, means for releasably locking the movable jaw in workpiece clamping position, a bending member hingedly connected to the fixed jaw, said movable jaw having its front edge spaced rearwardly of the front edge of said anvil surface when in clamping position, an extension member mounted on said front edge of said movable jaw and having a portion extending forwardly and forming an extension of the clamping surface, the region above said portion of said extension member being free and unobstructed such that the workpiece can be bent substantially beyond 900.

2. A sheet bending brake as claimed in claim 1, in which a spring-loaded floatable compensator is pivoted to said bending member and has a surface adapted to bear on said workpiece such that said compensator bends said workpiece to an angle exceeding 900.

3. A sheet bending brake as claimed in claim 1 or 2, wherein said extension member is generally L-shaped in cross section and said forwardly extending portion thereof is of substantially uniform thickness.

4. A sheet bending brake as claimed in claim 1 or 2, wherein said extension member mounted on said clamping member also has a portion defining the clamping surface, and the portion of said extension member defining said extension to the clamping surface extends beyond the front edge of said clamping member.

5. A sheet bending brake as claimed in claim 4, wherein said clamping member has an inner rear surface and a flat surface, and a slot in said rear surface, and said extension member has a first portion extending along said flat surface to define said clamping surface, a second portion extending along said inner surface and a third portion extending into said slot, said first portion extending beyond the front edge of said flat surface of said clamping member to define said extension to the clamping surface.

6. A sheet bending brake as claimed in any of claims 1 to 5, wherein said extension member is of substantially uniform thickness.

7. A sheet bending brake as claimed in any preceding claims, wherein the workpiece can be bent through an angle approaching 1800.

8. A sheet bending brake constructed substantially as herein described with reference to and as illustrated in the drawings.