Shear blade having a positive camber and method of adding a positive camber to a shear blade

Abstract

A hydraulically activated shear is provided. The shear includes: a first jaw; a second jaw configured to slide past the first jaw in a shearing motion; and a first cutting plate attached to at least one side of the first and second jaws, the first cutting plate defining a shear edge and a shear surface, the shear surface having a positive camber with respect to a plane perpendicular to the jaws, wherein at least one of the first and second jaws is actuated by a hydraulic cylinder.

We claim: 
     
         1 . A hydraulically activated shear comprising:
 a first jaw;   a second jaw configured to slide past the first jaw in a shearing motion; and   a first cutting plate attached to at least one side of the first and second jaws, the first cutting plate defining a shear edge and a shear surface, the shear surface having a positive camber with respect to a plane perpendicular to the jaws,   wherein at least one of the first and second jaws is actuated by a hydraulic cylinder.   
     
     
         2 . The shear of  claim 1 , wherein the first and second jaw pivot with respect to each other. 
     
     
         3 . The shear of  claim 1 , wherein the positive camber is within the range of 0.2 to 2 degrees. 
     
     
         4 . The shear of  claim 3 , wherein the positive camber is within the range of 0.45 to 1 degree. 
     
     
         5 . The shear of  claim 1 , wherein the first cutting plate is set within a cutting plate pocket defined within at least one of the jaws. 
     
     
         6 . The shear of  claim 5 , further comprising a shim located between the first cutting plate and the cutting plate pocket, the shim dimensioned to provide, at least in part, the positive camber. 
     
     
         7 . The shear of  claim 6 , wherein the first cutting plate is generally rectangular in cross-section. 
     
     
         8 . The shear of  claim 5 , wherein the cutting plate pocket is dimensioned to provide the positive camber. 
     
     
         9 . The shear of  claim 8 , wherein the first cutting plate is generally rectangular in cross-section. 
     
     
         10 . The shear of  claim 1 , wherein the first cutting plate is tapered and is thereby thicker at the portion of the first cutting plate that defines the shear edge than at the opposite side of the first cutting plate. 
     
     
         11 . The shear of  claim 1 , wherein the first cutting plate is removable from the jaw and can be moved, reoriented and reattached to the jaw to expose a different edge to be the cutting edge. 
     
     
         12 . The shear of  claim 1 , wherein the cutting edge is located furthest from the jaw to which the first cutting plate is attached than any other portion of the shear surface. 
     
     
         13 . The shear of  claim 1 , further comprising a second cutting plate located on the opposite jaw than the first cutting plate wherein the second cutting plate also has a positive camber. 
     
     
         14 . The shear of  claim 1 , wherein the first jaw is fixed and the second jaw pivots about the first jaw. 
     
     
         15 . A hydraulically activated shear comprising:
 a first means for shearing;   a second means for shearing configured to slide past the first means for shearing in a shearing motion; and   a means for providing a cutting edge attached to at least one side of the first and second means for shearing, the first cutting means defining a shear edge and a shear surface the shear surface having a positive camber with respect to a plane perpendicular to the jaws,   wherein at least one of the first and second jaws is actuated by a hydraulic cylinder.   
     
     
         16 . A shear comprising:
 a first jaw having a first side shear surface;   a second jaw having a second shear surface wherein the first and second jaws are configured to slide past each other and the first and second shear surfaces are nearly but not parallel, the first shear surface has a positive camber and is cambered toward the second shear surface.   
     
     
         17 . The shear of  claim 16 , wherein the angle of the camber is between 0.45 to 1 degree. 
     
     
         18 . The shear of  claim 16 , wherein the first and second jaws are pivotally connected and pivot with respect to each other. 
     
     
         19 . The shear of  claim 16 , wherein the shear surfaces are located on cutting plates that are removable from the jaws. 
     
     
         20 . The shear of  claim 19 , wherein the camber is caused by at least one feature from the following features: a shim located between the jaw and the cutting plate; a cutting plate pocket housing the cutting plate has a tapered surface; and the cutting plate itself is tapered.