US2302958A - Bending brake - Google Patents

Description

Patented Nov. 24', 1942 BENDING BRAKE John Jensen, Rockford, 111., assignor to Whitney Metal Tool Company, Rockford, 111., a corporation of Illinois Application July 13, 194.0,- Serial'No; 34.5.2247;

2 Claims.

The invention relates to sheet metal bending brakes generally and is concerned more particularly with an improved platen structure for use in such brakes.

One object of the invention is to provide an improved platen structure for brakes of the above general character which materially increases their range of utility by adapting them for the performance of a wider variety of operations than has heretofore been practicable.

Another object is to provide a general purpose brake of simple, inexpensive construction particularly suitable for transportation from one job to another and which is capable of performing all of the operations usually encountered under such conditions, the brake also being suitable for small shops or the like which require facilities for numerous sheet metal bending and forming operations but where the volume of work is insufficient to warrant the installation of separate machines such as have heretofore been used for the different operations.

' Still another object is to provide a sectional platen structure for bending brakes embodying one section capable of operating on sheets of heavier gauge than can ordinarily be handled by finger equipped box brakes and another section equipped with fingers for box bending whereby either type of work may be performed without requiring changes in or adjustment of z the brake.

Other objects and advantages of the invention .will become apparent from the following detailed description of the preferred embodiment illustrated in the accompanying drawing in which:

Figure 1 is a fragmentary perspective view of a bending brake platen and cooperating elements embodying the features of the invention.

Fig. 2 is a vertical sectional view showing details of the bed, platen, apron, and other elements of the brake. v

Figs. 3 to 6, inclusive, are digrammatic views showing a number of different set-ups for enabling the brake to perform various types of op erations.

By way of illustration, the invention has been shown and will be described herein as embodied in a bending brake of the general type shown in the Jensen Patent No. 2,028,869 granted J anuary 28, 1936. It will be understood, however, that the invention may be readily applied to other types of bending brakes. It will also be understood that various changes in the form, construction and arrangement of the parts may parting from the spirit and scope of;the invention as expressed in the appended claims.

. Referring now to the drawing, the brake selected to illustrate the invention comprises the usual frame including upright end members iii between which is fixedly supported a platen I l of novel and advantageous construction adapted .to cooperate with a bed l2 in clamping a metal sheet in place for a bending operation and to define a bending edge of variable length for the sheet. In the exemplary machine, the sheet to be operated on is supported by and clamped against the under side of the platen by the bed 12 which is disposed below the platen and uided for movement toward and from the same. The bed as herein shown comprises a rigid I beam l3 bolted or otherwise suitably secured at its ends to box-like brackets M (Fig, .2) slidable on the frame members It. A bed plate It is removably attached to the top of the I-beam so as to project forwardly therefrom. This plate constitutes the portion of the bed which cooperates with the platen to clamp the sheet in place during the bending operation.

Movement of the bed to and from clamping position may be efiected in any preferred man ner as by separate actuating mechanisms, similar to those disclosed in the above mentioned pat ent, associated with each end of the bed structure. One such mechanism is shown in Fig. 2 and comprises a hand lever I6 pivoted at one end on a head block I! rigid with the frame member In. This lever is connected by a link It with the head guiding bracket M, the link being arranged to shift-to an over-center position for holdingthe bed in its raised or clamping position. To facilitate its movement, the bed is desirably counterbalanced by a coiled compression spring l9 acting on the under side of each of the brackets l4.

Forbending a sheet clamped between the bed and platen, a swinging apron 20 is hingedly connected to the bed [2; The apron in its preferred form comprises a normally depending leaf 2| supported with its upper edge in the same plane as the upper surface of the bed plate I5 and as closely adjacent the front edge of the plate as is practicable. The upper edge of the leaf thus constitutes the active or bending surface of the apron. Toadapt the brake for making reverse bends spaced apart a distance less than the overall thickness of. the leaf 2|, the bending surface 7 is formed in part by a removable strip 22 conbe made by those skilled in the art without de- 55 stituting-approximately one half the thickness of the apron. The rigidity of the leaf is insured by a channel 23 welded to the back thereof.

At each end the leaf 2| is bolted or otherwise secured to a hinge strap 24 arranged to project upwardly at one side of an arm 25 rigid with the bracket l4. A pin 26 connects each strap and the adjacent arm for pivotal movement. As will be seen by reference to Fig. 2, the pins 26 are located so that the pivotal axis of the apron is substantially coincident with the upper front edge of the bed plate IS. The upper edge or bending surface of the leaf 2| accordingly remains at the same distance from the corner of the bed plate as the apron is rocked about its axis. Such rocking is effected in any convenient manner as by a hand lever 21.

The type of operation a bending brake is adapted to perform is determined to a large extent by the character of the platen installed in the brake. plated by the present invention is constructed and arranged with. a particular view to adapting the brake for the performance of a wide Variety of operations, including ordinary bending of either light or heavy gauge sheets as well as box work,

The improved platen structure contemwithout the necessity ofchanges in the set-up or adjustment of the brake in changing from one operation to the other. To this end the platen is constructed to present a fixed bending edge of substantially one half the length of the bed and is equipped with means providing a bending edge of variable length extending over the other half of the bed. These bending edges are accurately alined so that they may be used together or separately as the character of the operation dictates. Thus, it is possible to obtain a bending edge of any desired length within the capacity of the brake with a minimum of auxiliary apparatus such as is required for providing the variable length edge. Initial cost of the brake is therefore reduced and changes in the set-up for different types of work is facilitated.

In the preferred form illustrated in the drawing, the platen II is constructed in two sections 3| and 32 suitably joined together in end-to-end relation with the section 32 off-set rearwardly and upwardly with respect to the section 3|. The sections are desirably of the same length, each being substantially one half the length of the bed l2. of rigidity without excessive weight, the sections are preferably of generally triangular cross section. As herein shown, the sections, are secured together to form a rigid platen structure by bolts 33 inserted through a platen 34 welded to the innerend of the section 3| and fianges 35 on the adjacent end of the section 32.

The platen structure thus formed is supported in known manner above the bed l2 by slides 38 bolted or otherwise rigidly secured to the outer ends of the respective sections, the slides being grooved to receive a horizontal dovetail way 31 formed on the'adjacent head block I! of the frame. With this arrangement, the platen can be shifted bodily toward or from the front of the bed to accommodate sheets of different thickness. The adjustment of the platen structure is effected in the present instance by means of an adjusting screw 38 rotatably anchored in a lug 39 projecting inwardly from each head block H, the screw threading into the associated slide 36.

The triangular platen sections are mounted on the slides 36 so that their bases lie in planes substantiallyparallel ,to the plane of the bed plate l5'with the apex of the section 3| disposed To obtain ample strength, and a high degree closely adjacent the front edge of the bed plate. A blade-like member 40 extends along the apex of this section and defines the fixed bending edge of the platen. Preferably the blade member is removably secured to the platen structure so that it can be readily removed for repair or replacement when worn or damaged.

Due to the offset relation of the two platensections as hereinbefore explained, the apex of the section 32 is disposed above and substantially rearwardly of the front edge of the bed plate. This provides space for the mounting of the variable length edge forming means which this section of the platen is arranged to support. This means in its preferred form comprises a series of fingers 4| adapted to be detachably secured to the platen section and to project forwardly and downwardly therefrom to define a bending edge alined with the bending edge of the section 3|.

The fingers 4|, as herein shown, are all of the same shape, but preferably vary progressively in width so that they may be assembled in various combinations to provide bending edges of different desired lengths. As will be seen by reference to Fig. 2, each finger comprises a generally flat body portion 42 having at its front end a downwardly and forwardly projecting foot terminating in a triangular bending edge defining tip 43. Therear end portion of the body terminates in a hooked tail 44 adapted to engage in an undercut groove 45 in the under side of the platen section 32.

For holding the finger firmly in place on the platen, a clamping dog 46 is bolted thereto. The dog is arranged to abut at one end against a shoulder 41 upstanding from the surface of the be installed in any desired combination so as to form, either alone or in conjunction with the fixed edge provided by the blade 40, a bending edge of any desired length from that corresponding to the width of the narrowest finger to one substantially as long as the entire platen. Moreover, the fingers 4| can be spaced away from the .section 3|, if desired, to provide an independent bending edge of any desired length up to ap proximately one half the length of the platen. This is particularly advantageous for box work where the accurate adjustment of the length of the bending edges and the spacing of the fingers provides clearance for flanges previously formed on the sheet being operated on.

The fixed bending edge provided by the platen section 3| can, of course, be used alone for plain bending where the width of the sheet does not exceed one half the length of the platen. In fact this section is particularly suitable for bending metal of heavier gauges than can be formed 1 with the desired degree of accuracy by means of detachable fingers due to their inherent resiliency. Since the bending edge in this 'case' is an integral part of the rigid platen. structure, any possibility of yielding or bending is effectually avoided and sharp accurate bends. are insured.

[The installation of one or more fingers on the off-set section of the platen does not interfere in any way with the functioning of the fixed bending edge, hence, the brake can be set up to perform operations of several different types if desired.

The wide variety of operations that can be performed on a brake equipped with the improved platen herein described, will be readily appreciated from the above remarks. By way of illustration, a number of different set-ups have been shown diagrammatically in Figs. 3 to 6, inclusive, to more clearly indicate the range of utility of the brake. Thus, as shown in Fig. 3, the fingers 4| may be detached from the platen and the fixed bending edge provided by the section 3| used alone for bending a metal sheet S of any Width up to one half the width of the bed.

Alternatively, as shown in Fig. 4, a full complement of the fingers 4| may be installed to provide a continuous bending edge of substantially the same width as the bed for accommodating a wide metal sheet SI combination of the fingers 4! may be installed as shown in Fig. 5. It will be observed that in this case the innermost finger ll is spaced laterally away from the platen section 3!. This is to provide clearance for the fiange F previously formed on the sheet S2. Where the dimensions of the sheet permit, the flanges F may be formed over the bending edge of the section 3!, while the final bending operation is performed with the aid of the fingers assembly on the section 32. Thus, a series of box forming operations may be carried out with a single setting of the brake. Such a set-up also leaves the fixed edge accessible at all times for bending heavy gauge sheets without disturbing the box bending setup of fingers on the off-set section of the platen. This obviously saves time and labor and materially speeds up production.

Fig. 6 illustrates a set-up for box work involving a sheet S3 of somewhat greater width than the fixed edge of the platen section 3|. For this purpose the effective length of the fixed bending edge is extended by the installation of one or more fingers 4| as required. The unused fingers may be removed or, if desired, they may be shifted to the outer end of the section to provide the necessary clearance for the flange F.

A similar setting may be employed for bending heavy gauge sheets, that is, the fixed bending edge may be extended by the installation of one or more fingers 4|. Due to the rigidity of the platen section 3|, the strain imposed upon the fingers under these conditions is minimized so that accurate bending of a heavy gauge sheet is permitted.

For box work any It will be observed from the foregoing that the invention provides an improved platen structure for bending brakes, which materially increases the range of utility of such brakes. Due to the novel and advantageous construction of the platen, the brake in which it is installed is adapted to operate on metal sheets of a wider variety of gauges and to perform numerous operations that have heretofore been performed on separate machines. This extensive range is attained without complicating the brake structure which is simple and sturdy yet light in weight. Moreover, 1e brake may be readily converted for the performance of the various operations with little or no loss of time and with a minimum of effort.

I claim as my invention:

1. A bending rake having, in combination, an elongated bed, an apron mounted to swing about an axis substantially coincident with the front edge of the bed, a rigid platen extending longitudinally of said bed and arranged to cooperate therewith to clamp a metal sheet or the like in position to be bent by the swinging of said apron and to define the line on which the sheet is bent, said platen having two sections, one section presenting a fixed bending edge extending over a substantial length of the platen for direct engagement with the sheet to be bent, the other section of said platen being offset upwardly and rearwardly from said one section, said other section being operative to support a series of detachable fingers each having a projecting end defining a bending edge adapted to aline with the bending edge of said one section.

2. In a bending brake having a bed and a swinging apron arranged to pivot about an axis substantially coincident with the front edge of the bed, the combination of an elongated rigid platen supported above the bed for movement toward and from the same, said platen comprising two sections each extending substantially one-half the length of the bed, one of said sections presenting a bending edge positioned closely adjacent the front edge of the bed and adapted for direct engagement with a metal sheet or the like resting on the bed, the other of said sections having its front edge disposed above and offset rearwardly from the bending edge of said one section and operative to rigidly support one or more detachable fingers in a forwardly and downwardly projecting position with the outer ends of the fingers defining a bending edge alined with the bending edge of said one section.

JOHN JENSEN.

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