Patent Publication Number: US-3877279-A

Title: Sheet metal brake

Description:
United States Patent Van Cleave Apr. 15, 1975 1 SHEET METAL BRAKE [75] Inventor: Eugene H. Van Cleave, Redford,  
 Mich.  
 [73] Assignee: Van Mark Products Corporation,  
 Detroit, Mich.  
 [22] Filed: May 13, 1974 [21] Appl. No.: 469,506  
 abandoned.  
 [52] U.S. Cl 72/319; 72/465 [51] Int. Cl B2ld 5/04 [58] Field of Search 72/465, 466, 310, 319,  
 [56] References Cited UNITED STATES PATENTS 2,980,046 4/1961 McGregor 72/465 3,147,791 9/1964 Rauen et a1... 72/319 3,161,223 12/1964 Marsh 72/319 3,359,771 12/1967 Meyerchick 72/319 3,380,280 4/1968 Wise 72/319 3,481,174 12/1969 Barnack 72/319 3,559,444 2/1971 Blazey et a1. 72/319 3,592,037 7/1971 Van Cleave 72/319 Primary Examiner-C. W. Lanham Assistant Examiner-M. .1. Keenan Attorney, Agent, or FirmCullen, Settle, Sloman &amp; Cantor 57 ABSTRACT A brake for bending sheet metal including a frame, a fixed member secured thereto, a clamp to secure the sheet metal thereto and a bending member. The fixed member and the bending member have integral hinge projections which are pin connected for relative movement. The projections are contoured to avoid substantial contact with the sheet metal. A nonscratching resilient, member is secured on the lateral surface of the bending member. A wear-compensating bearing member in the frame aids in clamping the sheet metal to the fixed member.  
 3 Claims, 6 Drawing Figures PATENTEDAPmsms 3 87? 279 suzzraqg 58 FIG. 3  
  SHEET METAL BRAKE This is a continuation of application Ser. No. 302,141. filed Oct. 30. 1972 now abandoned.  
 BACKGROU ND OF INVENTION This invention relates to metal deforming in general. and. more particularly. to an improved brake for forming sheet metal and the like.  
  A sheet metal brake comprises. generally. a supporting surface. means to clamp a workpiece to the supporting surface. and a bending member pivotally mounted to said supporting surface, all shown. for example. in U.S. Pat. No. 3.161.223. issued to W. G. Marsh. Pivotally moving the bending member against the workpiece operates to bend the workpiece to the desired angle.  
  Various problems have been encountered with the prior art sheet metal brakes. For example. if a painted or otherwise finished metal is being formed. the means pivotally mounting the bending member to the support member. which typically is a hinge. may scratch or mar the finished surface of the metal.  
  A second problem arises from the relative movement of the bending member against the surface of the sheet metal. To understand this problem. it must be appreciated that the bending member pivots about the hinge while the sheet metal is being bent around the clamping means. Since these are different elements. there are two distinct axes of rotation. Thus the bending member slides against the surface of the sheet metal during the bending operation which also tends to mar the metal surface.  
 A third type of problem often arises with respect tothe clamping means for securing the workpiece to the support member. When a slidable ramp is utilized. the interaction between the various parts creates a great deal of friction and wear. Lubrication is unsatisfactory because the lubricating oils may stain the finish of the sheet metal. Furthermore. as the materials wear. compensation for the clamping means have not been provided prior to this invention.  
  Therefore. it is an object of the present invention to provide a new and improved sheet metal brake.  
  It is another object of the present invention to provide a sheet metal brake wherein the means for pivotally fastening the bending member to the support member are disposed away from and do not mar the workpiece.  
  It is a further object of the present invention to protect the finish of the workpiece by providing an improved bending member.  
  Yet another object of the present invention is to provide an improved clamping means which compensates for wear and which eliminates the need fora lubricant.  
 BRIEF DESCRIPTION OF THE DRAWINGS The foregoing objects of the present invention. together with other objects and advantages which may be attained by its use. will become more apparent upon reading the following detailed description taken in conjunction with the drawings. In the drawings. wherein line numerals identify corresponding parts:  
  FIG. 1 is a plan view illustrating the sheet metal brake of the present invention.  
  FIG. 2 is a front elevation view illustrating the clamping means ofthe present invention in an open position to permit insertion of the workpiece;  
  FIG. 3 is a front elevation illustrating the clamping means of the present invention securing a workpiece within the sheet metal brake;  
  FIG. 4 is a side elevation of the present invention as illustrated in FIG. 2;  
  FIG. 5 is an enlarged side elevation view of the present invention illustrating a workpiece clamped in position; and  
  FIG. 6 is a partial view of the present invention illustrating the operation of the improved bending member.  
 DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings, the sheet metal brake embodying the principals of the present invention comprises a plurality of rails 10, which may be in the form of] beams formed of metal extrusions. and a plurality of longitudinally spaced C-shape frame members 12 having lower arms 14 secured to rails and upper arms 16 disposed above the lower arm 14 in a spaced relation thereto.  
  Handles 18 may be secured to the rails 10 for convenient carrying of the sheet metal brake.  
  A support member 20 which may be in the form of a channel-shaped extrusion. is secured to the lower arm 14 of the C-shaped member 12. A bending member 22. preferably extruded and having a lateral surface 24. is hinged to the support member 20 as follows. Both the support member and the bending member have a plurality of longitudinally spaced apart projections 26. The projections on the bending member 22 are offset with respect to the projections on the support member 20 such that upon assembly the projections intermesh. Each projection has a longitudinal aperture 28 therethrough and the apertures are aligned such that a hinge pin 30 may be inserted through the alternating projections to form a hinge. Thus the bending member 22 may be swung or pivoted, with respect to the support member 20, with the hinge pin serving as a first axis.  
  The sheet metal brake includes an anvil 32 for securing a workpiece W against the support member 20. The anvil may be generally L-shaped having a lateral portion terminating in an edge 34 against which the workpiece may be bent and having an upright portion 36. An internal flange 37 runs the entire length of the anvil projecting outward from the back portion and downward.  
  The portion of the edge 34 which abuts the workpiece serves as an axis for rotation of the workpiece. It is noted that this axis is spaced apart from the first axis. Because of this non-coincidence of axes. the bending member slides along the surface of the workpiece during bending.  
  Means are provided for lamping the anvil into position to secure the workpiece W. Specifically. a pressure plate 38 has a groove which ispreferably dimensioned to fit receive the flange 37. A plurality of ramps or inclined planes 40 are secured to the pressure plate 38. The ramps each have an inclined upper bearing surface 42.  
  The means to support the pressure plate includes leaf springs 44 secured to the upper arm 16 of the C-shaped frame member and brackets 46 secured to the leaf spring and the back 36 of the anvil.  
  A lever 48 is pivotally secured to one end of a first link 50; the other end of the link is secured to the fixed support member 20. A second link 52 is pivotally connected between the lever arm 48 and one of the ramps 40.  
  Upon movement of the lever 48 from the position shown in FIG. 2 to the position shown in FIG. 3 the bearing surface 42 of the ramp 40 cooperates with the upper arm 16 to force the pressure plate 38 downward against the anvil and the anvil downward against the urging of the leaf springs 44 to clamp a workpiece between the anvil and the support member 20.  
  Means are provided to improve the clamping action as the ramps 40 are slidably engaged and eliminate the need for a lubricant. Specifically. a threaded. vertically disposed aperture 54 is provided in each upper arm 16 and an insert or screw 56 is threaded into the aperture and projects below the bottom of the upper arm 16. This screw, preferably manufactured of a material such as nylon, teflon or the like plastic material, cooperates with the upper or bearing surface 42 of the ramp 40. In this fashion, there is no metal to metal friction between the sliding ramp 40 and the arm 16 during the clamping action. As the clamping means starts to wear, the screw may be threaded further downward. Upon the nylon screw 56 wearing significantly, a replacement screw may be utilized.  
  Referring now to FIGS. and 6, a handle 58 is provided in the bending member 22 for pivoting the bending member about the hinge pin to bend the workpiece W. The lateral surface 24 of the bending member is provided with a re-entrant groove 60, extending longitudinally along the length of the bending member. A resilient, non-scratching strip 62 is inserted in the groove 60. The strip may have a generally L-shaped cross-section and includes a portion 64 which covers the lateral surface 24. Thus, the resilient strip, which may be made of a material such as plastic, nylon, teflon. or the like. provides the support and contact point between the workpiece and the bending member. In this fashion. a soft, non-marring strip is in contact with the workpiece rather than the metallic bearing surface of the prior art.  
  One additional feature to prevent marring the surface of the workpiece is provided in the contour of the projections 26. Specifically, the top surface of each projection 26 is recessed or contoured 66 along an axis parallel to the hinge pin 30. In this fashion, the projections 26 avoid substantial contact with the workpiece; the workpiece is supported by the anvil 32, the support member 20, and the resilient strip 62.  
  The foregoing is a description of the improved sheet metal brake of the present invention providing for an improved clamping member. an improved hinge member and an improved bending member. However, the foregoing is a description of one embodiment of the present invention. and therefore, should not be read in a restrictive sense, but only as describing the underlying concepts thereof. The invention may be further developed within the scope of the following claims.  
 What is claimed is:  
  1. In a brake for bending a workpiece, said brake having a frame, a support member secured thereto. clamping means exerting a force for holding a workpiece to said support member, and a bending member having a lateral working surface, said bending member hinged to said support member. the improvement comprising:  
 an elongated slot extending into said bending member along the length of said bending member, and opening onto said lateral working surface, said slot bounded by parallel side walls; and  
 an elongated resilient member of generally L-shaped cross-section having a first leg disposed in said slot and having a second leg overlying the lateral working surface of said bending member to be interposed between the working surface and said workpiece to prevent damage to the workpiece.  
  2. In a brake for bending a workpiece, said brake having a frame. a support secured thereto, said support member having a working surface, clamping means exerting a force for holding a workpiece to the working surface of said support member, and a bending member having a lateral working surface, said bending member hinged to said support member, the improvements comprising:  
 said support member and said bending member each having a plurality of integral spaced-apart projections, the projections on said support member being offset with respect to the projections of said bending member, and all of said projections having aligned apertures therethrough to receive a pin for defining a hinge, each of said projections on said support member being recessed below the support member working surface and each of said projections on said bending member being recessed inwardly of said bending member, each of said projections bending so recessed for preventing substantial contact between said projections and the workpiece;  
 an elongated slot extending into said bending member along the length of said bending member, and opening onto the lateral working surface. an elongated resilient member of generally L-shaped cross-section having a first leg disposed in said slot and having a second leg overlying the lateral working surface of said bending member to be interposed between the working surface and said workpiece to prevent damage to the workpiece. 3. In a brake for bending a workpiece, said brake having a frame. a support member secured thereto, clamping means exerting a force for holding a workpiece to said support member, and a bending member having a lateral working surface, said bending member hinged to said support member, the improvement comprising:  
 an elongated slot extending into said bending member along the length of said bending member, said slot having parallel side walls and an enlarged bulbous bottom and said slot opening into said lateral working surface; and  
 an elongated resilient bearing member of generally L-shaped cross-section having first and second legs with an enlarged bulbous portion at the distal end of said first leg, said first leg and bulbous leg portion disposed in said slot and slot bottom. respectively, and said second leg overlying the lateral working surface of the bending member and coextensive therewith for contacting said workpiece and isolating said workpiece from said bending member when said bending member is moved relative to said support member.