Heavy duty sheet bending brake

Abstract: A sheet bending brake comprising a first longitudinally extending member (13) having a clamping surface (14), means (17, 18, 19) movable toward and away from the clamping surface (14) for holding a workpiece in position for bending, and a second member (16) extending longitudinally with respect to said first member (13). Each of the first and second members have substantially the entire length of the longitudinal edges thereof formed with longitudinally spaced intermeshing integral projections (23, 27), the projections (27) on the second member (16) having a plurality of aligned openings (28) and the projections (23) on the first member (13) having a plurality of aligned slots (24) extending axially with respect to the longitudinal axis of said member. A hinge pin (29) extends through the openings (28) and the slots (24). The second member (16) has a workpiece contacting portion (31) spaced from the projections. The slots (24) have a configuration such that as the second member (16) is moved relative to said first member (13) to bend a workpiece, the hinge pin (29) is guided along said slots (24) such that the contacting portion (31) of said second member (16) remains substantially in the same position relative to the workpiece. A handle member (19) for manipulating the anvil member (17) is constructed to minimize the stresses thereon. The clamping member is constructed to maximize the strength thereof. A stabilizing assembly (56, 62, 63) is associated with the legs (55) on which the clamping brake is mounted.

Description: This invention relates to sheet bending apparatus according to the preamble of claim 1. In recent years, various structures have been provided to form a portable sheet bending apparatus for bending metal or plastic sheets such as are used in siding on homes and buildings. Typical patents comprise US-A-3,161,223, 3,481,173, 3,482,427, 3,559,444, 3,817,075, 3,872,755 and 4,321,817. Such apparatus comprise a fixed member on which the sheet is clamped and a movable bending member for bending the sheet. A major problem with respect to such sheet bending apparatus is the tendency of the bending member to move relative to the portion of the sheet being bent and thereby mar the surface of the sheet. In US-A-3,161,223, the tendency to mar the surface of the sheet material was minimized by having the intermeshing integral projection between the fixed member and bending member which extend longitudinally and define the hinge that connects the bending member with the fixed member having the clamping surface, positioned so that all portions of the projections do not extend above the plane of the surface of the members when the surfaces are substantially aligned. US-A-3,481,174 and 3,482,427 were directed to an arrangement which included a floatable compensator on the bending member which engages the sheet material and as the bending member is swung to bend the sheet pivots so that the contact with the sheet material is maintained. A portable apparatus according to the preamble to claim 1 is known from US-A-4,557,132. When working with this apparatus, a platform or other supporting structure is needed to fix the apparatus in place. Accordingly among the objectives of the present invention and to provide a sheet metal bending apparatus which is relatively light in weight, portable and less costly, and includes a supporting structure which is also portable. The invention is defined in claim 1. Briefly, each of the fixed and movable bending members have substantially the entire length of the longitudinal edges thereof formed with longitudinally spaced intermeshing integral projections. The projections on the bending member have a plurality of aligned openings and the projections on the fixed member have a plurality of aligned openings in the form of arcuate slots. A hinge pin extends through the openings of said bending member and the slots of the fixed member. As the bending member is moved relative to the fiexed member to bend a workpiece, the hinge pin is guided along said arcuate slots such that the contacting portion of the bending member remains substantially in the same position relative to the workpiece. Locking means includes a clamping anvil member and a handle member for manipulating the clamping or anvil member which is constructed to minimize the stresses thereon and to maximize the strength thereof. A stabilizing assembly is associated with the legs on which the apparatus is mounted. An embodiment of the invention is shown in the drawings in which; Fig. 1 is a perspective view of a sheet bending apparatus; Fig. 2 is a vertical sectional view of a detail; Fig. 3 is a fragmentary vertical section view of a handle member; Fig. 4 is a fragmentary sectional view of the detail in Fig. 2, yet showing the parts in a different operative position; Fig. 5 is a plan view of a stabilizing assembly; Fig. 6 is a fragmentary elevational view thereof; Fig. 7 is a sectional view taken along the line 7-7 in Fig. 6. Referring to Figs. 1-4, the sheet bending apparatus embodying the invention comprises longitudinally spaced C-shaped frame members 10. Each frame member includes a lower arm 11 and an upper arm 12 which overlies the lower arm 11 in spaced relation thereto. A first fixed member 13 is fixed on the ends of the free lower arms 11 and defines a clamping surface 14. A longitudinally spaced base rail 15 is fixed to the rear end of the lower arms 11. A second bending member 16 is hinged to the first member 13, as presently described, to provide a means for bending the sheet material S. Clamping anvil member 17 extends longitudinally in overlying relationship to the clamping surface 14 of the first member 13. Means 18, 19, 19a are provided for moving the anvil member 17 toward and away from the clamping surface 14 to clamp the workpiece S on the clamping surface. These means include bars 18, a handle member 19 and a plurality of links 19a. The bars 18 are channel shaped and pivoted on each frame member 10 with the clamping member 17 fixed on the free ends thereof. The handle member 19 is pivoted to the upper arm 12 of each C-frame member 10 at 41 and connected to the pivot bars 18 by the plurality of links 19a which are extensible and pivoted at the upper end to the handle member 19 and at the lower end to the pivot bars 18. The first member 13 having the clamping surface 14 is formed as an aluminum extrusion and includes an upper tubular portion 20 and a lower U-shaped portion 21 including spaced flanges 22 engaging the free ends of lower arms 11. A plurality of longitudinally spaced projections 23 are provided as parts of the hinge to the second, bending member 16. Each projection 23 has a slot 24 formed therein and the slots 24 of the various projections 23 are in longitudinal alignment. Each slot 24 has its lower end spaced from the clamping surface 14 and extends outwardly and upwardly so that its upper end is generally near the plane of the clamping surface 14. Each slot 24 is preferably arcuate and preferably extends for substantially 90°, yet the center is spaced from the clamping surface 14. The second, bending member 16 is also in the form of an extrusion including a tubular portion 25 and a longitudinally extending leg 26 with a plurality of longitudinally spaced projections 27 having openings 28 therein. The projections 27 of the bending member 16 mesh with the projections 23 of the fixed member 13 and a pin 29 extends through the openings 28 and slots 24 to hinge the bending member 16 to the fixed member 13. The bending member 16 further includes a tooling portion 30 that extends upwardly and outwardly when the bending member 16 is initially in position for bending. A longitudinally extending plastic strip 31 is fixed in a generally L-shaped recess 32. The strip 31 includes a short leg 33 having an enlarged end portion 34 for engaging the recess 32. The other leg 35 of the strip 31 extends along the tooling portion 30 to define a sheet contacting portion. The strip 31 is preferably made of polyurethane. The fixed member 13 further includes a recess 36 extending longitudinally at the juncture of the clamping surface 14 and the projections 23. Recess 36 functions as a pocket into which any burrs may fall from a knife used for scoring the workpiece. The clamping surface 14 is spaced slightly above the projections 23 in order to minimize marring of the surface of the workpiece when it is inserted and removed. The bending member 16 also includes a recess 37 extending longitudinally between the projections 27 and the plastic strip or contacting portion 31. In use, a workpiece of sheet material S is clamped against the clamping surface 14 by pivoting the handle member 19 and moving the bars 18 and the clamping anvil member 17 towards the first fixed member 13. Then the bending member 16 is moved by swinging the handle H upwardly so as to bring the contacting portion 31 of the bending member 16 in engagement with the sheet material S. As the bending member is swung upwardly, the hinge pin 29 on the bending member 16 moves along the slots 24 and is guided in a fashion such that the contacting portion 31 maintains substantially the same relative position of contact to the sheet material thereby minimizing marring of the surface of the sheet material. As shown in Figs. 2 and 4, the arcuate slots 24 extend generally from below the nose or bending edge of the clamping anvil member 17 upwardly and outwardly toward the user so that the hinge pin 16 moves along the slots 24 as the workpiece is being bent from the position in Fig. 2 to the position in Fig. 4. Then the hinge pin 29 reaches the upper end of the slots 24, which end forms the fulcrum for the further movement of the bending member 16 (shown in phantom in Figure 4) to bend the workpiece into contact with the upper inclined surface of the clamping member 17. In accordance with the invention, in order to provide for bending of thicker sheet metal, certain modifications in the construction have been utilized which cooperate to produce a sheet metal bending apparatus which will effectively bend such sheet metal even though the sheet bending apparatus is not heavy and relatively portable. It has heretofore been thought to be impossible to provide a portable sheet metal bending apparatus that will readily bend sheet metal of increased thickness and hardness. In accordance with the invention, the handle member 19 which is connected to the members 10 by pins 41 and to the links 19a by pins 42 is provided with recesses 43, 44 (Fig. 3) defined by integral portions 45, 46, 47 and 48, respectively, that are positioned so that the recesses 43, 44 lie substantially in the circle of the body of metal of the hollow handle member 19 thereby improving substantially the strength of the handle member. In addition, the anvil or clamping member 17 is formed so that it has a tubular cross section including a heavy upper wall 49 and a lighter lower wall 50 generally parallel to the wall 49 and connected thereto by integral inclined portions 51, 52. The tubular portion extends rearwardly from the clamping portion 53. It has been found that such a construction contributes substantially to the strength of the sheet bending apparatus and the resultant ability to bend relatively thick sheet metal. Further, in accordance with the invention, a stabilizing assembly is added to the legs 55 which may be fixed or folded and attached to the members 13 and 15. The stabilizing assembly comprises spaced tubular transverse rails 56 which are preferably rectangular in cross section having openings 58, 59 for receiving the feet 60, 61 of the legs 55. Longitudinally extending hollow rails 62, 63 are fixed to extend lengthwise of the apparatus between the rails 56. The feet 60, 61 are preferably locked to the rails 56 by a pin 65 extending through the feet 60, 61 and the rails 56, 57. The pin 65 is retained by a clip 66 that is hinged to the head of the pin 65 and releasably connected to the free end of the pin 65 as shown in Fig. 7. In use, as shown in Fig. 1, a person utilizing the sheet bending apparatus inserts the sheet S and clamps it in position by manipulating the handle 19. The person further places one or both feet on one or both of the rails 62, 63 and simultaneously lifts the bending member 16 by means of one or more handles H. Where the length of the apparatus is on the order of 3 m (ten feet) or more and the sheet being bent is more, two persons of less stature may manipulate the apparatus by each person grasping a handle and placing one or both feet on the rails of the stabilizing assembly. It has been found that by the use of such a stabilizing assembly, the force opposing the movement the bending member 16 is counteracted and the bending is facilitated. It has been found that a sheet bending apparatus embodying the invention is portable and yet permits bending of the sheet material which has a thickness substantially more than that heretofore thought possible. In tests conducted to date it has been found that the sheet material can be readily bent. The results are summarized in the following table:

Claims: A sheet bending apparatus comprising a first longitudinally extending member (13) having a clamping surface (14), means (17, 18, 19) movable toward and away from the clamping surface (14) for holding a workpiece in position for bending, a second member (16) for bending a workpiece clamped on said clamping surface (14) extending longitudinally with respect to said first member (13), means (23, 24, 27, 28, 29) hinging said second member (16) to said first member (13), characterized in that the apparatus comprises a stabilizing assembly comprising longitudinally spaced legs (55) on said sheet bending apparatus, transversely spaced rails (56) receiving the ends (60, 61) of said legs (55), and at least one longitudinally extending rail (62, 63) interconnecting said transverse rails (56) and being arranged in a lateral distance below the second member (16) toward the operator such that the operator may place one or both feet on the longitudinal rail during the movement of the bending member (16) for performing the bending. The sheet bending apparatus set forth in claim 1 including means (65, 66) removably connecting said legs (55) to said transversely spaced rails (56) of said stabilizing assembly. The sheet bending apparatus set forth in claim 1 or 2 wherein said sheet bending apparatus comprises a base, a plurality of C-shaped members (10) positioned on said base at longitudinally spaced points, each said C-shaped member (10) comprising a lower arm (11) fixed to said base and an upper arm (12) spaced from and overlying said lower arm, said first member (13) being fixed to the lower arms (11) of said C-shaped members (10), each of said first (13) and second (16) members having substantially the entire length of the longitudinal edges thereof formed with longitudinally spaced intermeshing integral projections (23, 27), the projections (23) on said first member (13) having a plurality of aligned slots (24) extending axially with respect to the longitudinal axis of said member, the projections (27) on said second member (16) having a plurality of aligned openings (28) extending axially with respect to the longitudinal axis of said member, a hinge pin (29) extending through said openings (28) of said second member (16) and said slots (24) of said first member (13), said second member (16) having a fixed workpiece contacting portion (31) spaced from the projections (27), said workpiece contact portion (31) being fixed relative to said hinge pin (29), said slots (24) having a configuration such that as the second member (16) is moved relative to said first member (13) to bend a workpiece, the hinge pin (29) is guided along said slots (24) such that the contacting portion (31) of said second member (16) remains substantially in the same position relative to the workpiece during the bending operation, said means (17, 18, 19) movable toward and away from the clamping surface (14) includes a handle (19) that is pivoted to said first member (13) and to said second member (16). The sheet bending apparatus set forth in claim 3 wherein said handle member (19) includes spaced recesses (43, 44) for receiving pins (41, 42) on respective members (12, 19a).. The sheet bending apparatus set forth in claim 3 or 4 wherein said movable means (17, 18, 19) include a hollow clamping member (17). The sheet bending apparatus set forth in claim 5 wherein said hollow clamping member (17) comprises spaced generally parallel walls (49, 50), said walls including an upper wall (49) having a greater thickness than said lower wall (50) and integral portions (51, 52) connecting said two walls (49, 50). The sheet bending apparatus set forth in claim 4, 5 or 6 wherein said recesses (43, 44) of said handle member (19) are lying substantially in the main body of the handle member (19). The sheet bending apparatus set forth in claim 3 including pivot bars (18) pivoted to said C-shaped clamping members (10) and said camping member (17) is pivoted on said pivot bars (18), a plurality of links (19a) interposed between said handle member (19) and said pivot bars (18), a first set of pivot pins (41) on the upper arms (12), said tubular handle member (19) having spaced recesses (43, 44) for receiving said pivot pins (41), a second set of pins (42) on each said extensible link (19a), said tubular handle (19) having recesses (44) for receiving said second set of pins (42), said recesses (43, 44) extending radially inwardly and lying substantially with the confines of the tubular body of the handle member (19).

Inventors: CHUBB ARTHUR B, SUYAK JAMES E, CHUBB, ARTHUR B., SUYAK, JAMES E.
Applicants: TAPCO PRODUCTS CO, TAPCO PRODUCTS COMPANY, INC.
Application year: 1992
Main classification: B21D5
IPC codes: B21D5