Title:
Portable bending brake
United States Patent 2181566


Abstract:
The invention relates to a brake for bending sheet metal and more particularly to portable brakes of this type. Most bending brakes for sheet metal heretofore 6 available were very heavy and unwieldy. It has been the general practice to locate them in shops or factories where sheet metal structures...



Inventors:
John, Jensen
Application Number:
US8791936A
Publication Date:
11/28/1939
Filing Date:
06/29/1936
Assignee:
WHITNEY METAL TOOL COMPANY
Primary Class:
International Classes:
B21D5/04
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Description:

The invention relates to a brake for bending sheet metal and more particularly to portable brakes of this type.

Most bending brakes for sheet metal heretofore 6 available were very heavy and unwieldy. It has been the general practice to locate them in shops or factories where sheet metal structures were preformed either as a whole or in sections and then transported to the point of installation. This practice has proved to be particularly unsatisfactory and the source of many vexatious delays in the installation of conduits in houses and office buildings for air conditioning systems, for example, since the sheet metal work required is quite extensive and must be specially formed to fit the particular dimensions and irregularities of the structure in which it is placed.

The principal object of the present invention is to provide a bending brake that is simple and light in construction without sacrifice in ruggedness and rigidity of parts, its parts being arranged in a novel manner such that the complete machine can be readily transported to and operated at various places where the sheet metal articles formed thereon are to be used.

Another object of the invention is to provide a machine of the character described which is readily and accurately adjustable to bend metal sheets of different thickness, and which may be readily adapted to perform a variety of different types of bending operations, thus obviating the necessity of transporting several machines to the place of installation for performing the various bending operations required.

Further objects and advantages of the invention, will become apparent as the following description proceeds and the features of novelty, which characterize the invention, are pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the invention reference may be had to the accompanying drawings, in which: Figure 1 is a perspective view of a bending brake embodying the present invention.

Fig. 2 is an end view of the machine shown in Fig. 1 with certain parts broken away.

Fig. 3 is a transverse section of the bending brake shown in Fig. 1 illustrating particularly the detachable fingers secured to the platen for use in bending box forms and the like, and Fig. 4 is a perspective view of a portion of the machine shown in Figs. 1 to 3, further illustrating the detachable fingers included in Fig. 3. As shown in the drawings, the invention herein disclosed is embodied in a portable bending brake particularly adapted for performing various bending operations on sheets of metal.

The bending brake illustrated includes as its principal working elements a movable pair of jaws formed by the platen 10 and a bed I I adapted to clamp a sheet of metal therebetween and an apron 12 adapted to bend the clamped sheet of metal about the forward edge of the platen when swung toward the same. The bed is as light in construction as is possible in view of the heavy compressive forces which it is required to withstand. In the machine illustrated, the bed is formed by a bar or wear plate 13 extending along the forward edge of a steel 1I beam 14 having a T-shaped cross section. The flat upper portion of the beam forms an ample support for certain parts of the brake such as the wear plate 3 while the vertical portion thereof forms a strengthening web adding rigidity to the structure. The bar 13 is preferably welded as indicated at 15 (Fig. 3), or otherwise rigidly secured to the beam 14 by the fusion of metal, thus eliminating any bolts or the like in the connection. The beam 14 thus forms a rigid light- 2ff weight support for the bar 13. It will be understood that the bar or wear plate 13 may be readily replaced by a duplicate member if it becomes scarred or otherwise injured after continued use.

The beam 14 is supported on a frame work which is of minimum height and weight in order that the bending brake may be supported on a work bench or in any similar place which happens to be convenient at the building in which the sheet metal work is being installed. The frame work illustrated includes a pair of rectangular end members designated by the numeral 16.

Each of the end members 16 includes a generally U-shaped portion 17 made of a continuous piece of angle iron bent to the desired shape. An offset 18 is formed in the forward legs of each of the members 17 so as to accommodate the apron 12 as well as the linkage mechanism for operating the platen 10. At the same time, the elon- 45; gated bottom faces of the members 17 form a base located closely adjacent the bed II and of maximum length from front to rear thus imparting a high degree of stability to the structure.

The upper ends of the legs of the members 11 are joined by transversely extending angle irons or rails 19. The end portions of the beam 14 are rigidly secured to the adjacent upper front corner portions of the end frames 16 by bolts 14a and 14b, while the rear upper corner por- 56ยท tions of the end frames are secured together by a tie-bar 20.

The bending brake is illustrated in Fig. 1 as supported on a light frame work consisting ot rectangular end members 16a made of angle iron and having their lower portions secured together by a tie-rod 16b. The lower sides of the end member 17 of the brake are detachably secured to the horizontal upper rails of the frames 16a by bolts ITa. The brake may be readily removed from the frame work illustrated by detachment of the bolts 17a.

The platen 10 is preferably of fabricated construction in order to minimize its weight. In the machine illustrated, the platen is of generally box-like construction and includes an angularly disposed face plate 21 reinforced by a supporting structure which is triangularly shaped in cross section, being formed by plates 22 and 23 welded to each other and to the edge portions of the face plate 21. The lower forward edge of the face plate 21 carries a blade 24 constituting the bending edge proper of the platen. It will be noted that the blade 24 forms a continuous bending edge extending substantially throughout the longitudinal length of the platen 10. The blade 24 thus cooperates with the bar 13 to clamp and support a sheet of metal therebetween.

The platen 10 is movably supported and is op30. erable by a simple form of linkage mechanism to move the same toward and away from the bed S1 in a substantially vertical direction. The supporting arrangement for the platen 10 includes a pair of levers 25 welded to the opposite ends thereof as indicated at 26. As shown in Figs. 1 and 2, the rear ends of the levers 25 are connected to brackets 27 by pivot pins 28 when the bending brake is conditioned for forming continuous bends in plane sheets of metal. An arrangement hereinafter described is also provided for shifting the points of pivotal connection between the levers 25 and brackets 27 when detachable bending fingers are secured to the platen 10 in order to effect box bending operations and the like. As shown in Fig. 2 the brackets 27 are adjustably secured to the rails or angle irons 19 by bolts 29 passing through suitable slots formed in the horizontal portions of the rails 19. Adjusting screws 30 and 31 threaded in brackets 32 0. and 33, respectively, bear against the opposite ends of the bracket 27 and may be utilized to adjust the same to the exact position desired for bringing the forward edge of the blade 24 into alinement with the forward edge of the bar 13. 56 The platen 10 is moved into and out of clamping engagement with a sheet of metal interposed between the bed and the platen by a linkage mechanism including independent manual operating levers 34 positioned at opposite ends of the bending brake. The lower U-shaped ends of the levers 34 are pivotally supported by a shaft 35 extending therebetween and journaled in suitable forwardly extending brackets 36 secured to the forward legs of the U-shaped frame member 17. The forward ends of the levers 25 are connected to the operating levers 34 by links 37. It will be noted that the upper ends of the links 37 are pivotally connected to the levers 25, while the lower ends thereof are pivotally connected to the Ushaped lower end portions of the manual operating levers 34 at points eccentric wtih respect to the shaft 35. It will thus be seen that when the manual operating levers are rotated from the position shown in Figs. 1 and 2 that the links 37 76 will be moved upwardly, consequently swinging the levers 25 in a clockwise direction about their pivots 28 and thus moving the platen 10 away from the bed II. The pivots 28 are preferably located above the plane of the bed 11 and at a maximum distance laterally therefrom so that the horizontal component of the movement of the platen 10, during its swinging motion about the pivots, will be minimized. It will be noted that the shaft 35 interconnects the operating mechanisms at the two ends of the brake so that it may be operated at will from either end. Moreover the position of the shaft 35 in the offsets in the front frame work legs prevents its interference with the rest of the machine.

The apron 12, hingedly connected to the bed and operable to bend a sheet of metal secured between the bed and platen, consists in general of: a normally depending leaf 40 supported with its upper rear edge as nearly as possible coincident with the upper front edge of the bar 13 on the bed I . Hinge straps 41 are bolted to the opposite ends of the leaf 40. These hinge straps are provided with enlarged forked upper ends 43 journaled on pins 44 mounted in hinge brackets 45 bolted to the opposite ends of the beam 14. Bars 46 are secured to the inner face of the leaf 46 adjacent the ends thereof and form handles for swinging the same upwardly into operative relation with a sheet of metal clamped between the platen and the bed. The apron 12 and platen 10 are provided with reinforcing trusses 12a and 10a, respectively. From the foregoing it will be seen that the operating mechanism of the bending brake is sufficiently compact that it is located entirely above the lower surfaces of the supports :5 S7 and may consequently be operated free of interference when placed on a work table or the like.

When the machine is arranged, as shown in Pig. 1, it is adapted to form continuous bends in plane sheets of metal about the elongated edge of the blade 24 on the platen 10. In many instances, however, it is desirable to form discontinuous bends in a sheet of metal as, for example, when box forms are being made. Consequently, an arrangement has been provided by means of which the machine illustrated may be adapted for performing this latter type of bending operation. As a result, the utility of the machine is greatly enhanced as well as the practicability of 50: its use at the site on which the sheet metal work is to be erected, since the necessity of providing separate machines for various types of bending operations would greatly handicap the workmen in this latter type of operation. The arrange- .ri ment for converting the machine to a box bending brake includes, in general, a plurality of bending fingers which may be detachably secured to the platen 10.

In the preferred arrangement illustrated in 6O Figs. 3 and 4, for example, bending fingers 47 are detachably secured to the platen 10. The detachable securing arrangement includes a rearwardly disposed hooked portion 48 which fits over an undercut plate 49 detachably secured to the 6( lower face of the platen 10. After the rear portion 48 of the fingers 47 has been hooked over the plate 49, the front portion of the fingers is secured to the blade 24 by an undercut plate which is detachably secured to the fingers 47 by 70 bolts 51. As best shown in Fig. 3, when the fingers 47 are thus positioned on the platen 10, the forward edge thereof is arranged substantially in alinement with the forward edge of the bar 13 on the bed I i. To position the fingers in this way 75: it is necessary, however, to shift the platen 10 t to the rear. In order to accomplish this, apertures 52, adapted to receive the pivot pins 28, are preferably formed in the intermediate portions of the supporting levers 25.

The link 37 of the operating mechanism is preferably made in extensible form so as to accommodate the difference in position of the lever 25 when the fingers 4 aresecured in place on the platen 10. In the particular machine illustrated, the links 37 include end members 52 and 53 having their adjacent ends threaded in turn buckles or adjusting collars 54. The lengths of the links 37 may thus be conveniently varied to accommodate the change in position of the platen 10 by threading the members 52 and 53 into or out of the collars 54. This adjustable construction of the links 31 is also advantageous in that the spacing of the blade 24 from the bar 13 on the bed 1 may be conveniently varied by changing the length of the links 37 in order to accommodate sheets of metal of different thicknesses when the blade 24 is being utilized without the fingers 47 to perform plane sheet bending operations. The pivotal supporting brackets 27 may be adjusted along the rails 19 to bring the forward bending edges of the fingers 47 or blade 24, as the case may be, into registry with the forward edge of the bar 13 after the desired changes have been made in the operating and supporting linkages of the platen 10. A sheet of metal 41a is shown in Fig. 4 clamped between fingers'47 and bed 13 prior to bending the same in a box form. The fingers accommodate the upturned edges of the sheet. From the foregoing it will be apparent that a bending brake has been provided which is extremely light in weight without sacrifice in rigidity and ruggedness of construction. The improved form of frame work and mounting arrangement for the parts of the bending brake contribute materially to this reduction in weight as does the fabricated construction of the platen and bed. This improved form of fabricated construction of the platen and bed effects a reduction in weight by the elimination of gusset plates and similar bracing members, as well as a large number of bolts and the like. It should also be noted that the improved bending brake illustrated is constructed largely of standard structural steel parts or forms so that the cost of manufacture is likewise, minimized.

Although a particular embodiment of the invention has been shown and described in detail for purposes of illustration there is no intention to thereby limit the invention to the particular construction illustrated but on the other hand the appended claims are intended to cover all modifications within the spirit and scope of the invention.

I claim as my invention: 1. A portable sheet metal bending brake comprising, in combination, a bed including a rigid horizontal beam, a supporting frame work for said bed including substantially U-shaped members formed from continuous lengths of metal atached to the ends of said beam, the base portions if said U-shaped members being located closely adjacent said beam to minimize the height of the brake and being elongated from front to rear to impart a high degree of stability to the brake, the small height of the brake permitting ready portability thereof and alternative mounting on either a suitable frame work or bench, a platen pivotally mounted on said frame work, means including an operating mechanism located wholly above said bottom portions of said U-shaped members for swinging said platen toward and away from said bed to clamp a sheet of metal therebetween, and an apron hingedly mounted on said beam and swingable toward said platen to bend a sheet of metal clamped between said bed and platen, the front legs of said U-shaped members being provided with inwardly extending offset portions therein adapted to accommodate said apron when in its lowermost position. 2. A portable sheet metal bending brake comprising, in combination, a bed including a rigid horizontal beam, a supporting frame work for said bed including substantially rectangular end members secured to the ends of said beam and adapted to support the same on a table or the like, a platen pivotally mounted on said frame work, said end members being provided with elongated base portions extending from front to rear thereof and located closely adjacent said beam, the front legs of said rectangular end members being disposed rearwardly of the front ends of said base portions, a platen pivotally mounted above said bed for swinging movement toward and away from the same, operating mechanisms located at each end of said beam and operable at will from either end thereof for moving said platen toward and away from said bed, means including a shaft extending along the front of said front legs and supported thereon for interconnecting said operating mechanisms in operative relation, and an apron hingedly mounted on said beam and swingable toward said platen to bend a sheet of metal clamped between said bed and platen. 3. A bending brake comprising, in combination, a frame work, a bed carried by said frame work, brackets mounted for horizontal sliding movement on said frame work, means for detachably securing said brackets in a selected position on said frame work, a platen having a forwardly disposed continuous bending edge and rearwardly extending supporting arms, fingers adapted to be carried by said platen to provide a discontinuous box bending edge located forwardly of said continuous bending edge, means for pivotally connecting said arms to said brackets at either of two selected points along said arms to bring one or the other of said bending edges approximately into alinement with the bed, the adjustment of said brackets serving to effect the exact alinement desired, and a bending apron hingedly supported on said bed.

JOHN JENSEN. 85