Metal bending with an anti-galling bend fixture

Abstract

A bend fixture for bending metal sheet includes a stationary platen, a hinged platen, and a hinge associated with the hinged platen. Each platen includes an exterior surface portion for supporting a metal sheet; an interior surface portion spaced from the exterior surface portion; and a slanted surface portion between the interior and exterior surface portion. The exterior surface portions of the platens are initially separated by a gap. Rotating the hinged platen about the hinge narrows the gap and causes the slanted surface portions to approach each other. A clamp above each platen supports the metal sheet adjacent the platens as the hinged platen is rotated. Bending metal sheet with the claimed bend fixture avoids surface galling associated with prior art sheet bending techniques relying upon interaction between a punch and a die.

1 . A method for bending a metal sheet comprising: 
 (a) providing a bend fixture comprising a first platen and a second platen separated from the first platen by a gap, at least one of said platens being connected with at least one hinge,    said first platen and said second platen each having an exterior surface portion, an interior surface portion spaced from the exterior surface portion, and a slanted surface portion extending angularly between an inner edge of the exterior surface portion adjacent said gap and an inner edge of the interior surface portion spaced from said gap, said exterior surface portion including a generally planar principal portion spaced from the gap and a convexly curved end portion between the principal portion and the inner edge of the exterior surface portion,    (b) supporting a metal sheet adjacent said principal portions of the first and second platens, said metal sheet being spaced exteriorly of the inner edges of the exterior surface portions of the first and second platens, and    (c) rotating at least one of said first and second platens about said hinge while retaining said metal sheet adjacent exterior surface portions of the first and second platens so that said slanted portions of the first and second platens approach each other, portions of the metal sheet adjacent the gap approach the curved end portions of the platens, and said metal sheet bends in a bend zone extending transversely across said sheet adjacent said curved end portions.    
   
   
       2 . The method of  claim 1  wherein step (b) includes clamping said metal sheet to said principal portion of the first platen with a first clamp and clamping said metal sheet to said principal portion of the second platen with a second clamp spaced from said first clamp.  
   
   
       3 . The method of  claim 1  wherein said metal sheet includes at least one vane extending laterally outwardly and step (b) includes positioning at least one pilot pin adjacent said vane.  
   
   
       4 . The method of  claim 1  wherein said principal portions of the first and second platens are generally coplanar.  
   
   
       5 . The method of  claim 1  wherein the first platen is stationary and the second platen is hinged.  
   
   
       6 . The method of  claim 5  wherein the second platen is connected with hinge pins located on opposite lateral sides of the second platen.  
   
   
       7 . The method of  claim 1  wherein said exterior surface portions of the first and second platens are generally parallel to the interior surface portions.  
   
   
       8 . The method of  claim 1  wherein said bend zone extends linearly across an entire width of said metal sheet.  
   
   
       9 . The method of  claim 1  wherein step (c) includes bending said metal sheet at an angle of about 90°.  
   
   
       10 . The method of  claim 1  wherein in step (c) said slanted portions of the first and second platens approach each other.  
   
   
       11 . The method of  claim 1  wherein said metal sheet comprises a metal selected from the group consisting of zirconium alloys, steel, aluminum alloys, and copper alloys.  
   
   
       12 . The method of  claim 1  wherein said metal sheet comprises a zirconium alloy.  
   
   
       13 . A method for bending a metal sheet comprising: 
 (a) providing a bend fixture comprising a stationary platen and a hinged platen separated from the stationary platen by a gap, said hinged platen including hinges on opposite lateral sides thereof,    said stationary platen and said hinged platen each having an exterior surface portion and an interior surface portion spaced from the exterior surface portion, said exterior surface portion including a generally planar principal portion spaced from the gap and a convexly curved end portion between the principal portion and an inner edge of the exterior surface portion adjacent said gap,    (b) clamping a metal sheet to the stationary platen with a first clamp and clamping said metal sheet to the hinged platen with a second clamp spaced from said first clamp, and    (c) rotating said hinged platen about said hinges while retaining said metal sheet adjacent exterior surface portions of the first and second platens so that said metal sheet bends in a bend zone extending transversely across said sheet.    
   
   
       14 . The method of  claim 13  wherein said metal sheet bends at an angle of about 90°.  
   
   
       15 . A bend fixture for bending metal sheet, comprising: 
 (a) a stationary platen,    (b) a hinged platen separated longitudinally from the stationary platen by a gap, said stationary platen and said hinged platen each including an exterior surface portion for supporting a metal sheet, an interior surface portion spaced from the exterior surface portion, and a slanted surface portion extending angularly between an inner edge of the exterior surface portion adjacent said gap and an inner edge of the interior surface portion, each said exterior surface portion including a generally planar principal portion spaced longitudinally from the gap and a convexly curved end portion between the principal portion and an inner edge adjacent the gap,    (c) at least one hinge attached to the hinged platen, and    (d) a first clamp for holding a metal sheet adjacent said exterior surface portion of the stationary platen and a second clamp for holding the metal sheet adjacent said exterior surface portion of the hinged platen when the hinged platen is rotated about the hinge to bend the metal sheet.    
   
   
       16 . The bend fixture of  claim 15  wherein the inner edge of the interior surface portion of each said platen is spaced longitudinally from the gap.  
   
   
       17 . The bend fixture of  claim 15  further comprising at least one pilot pin extending exteriorly of the stationary platen, said pilot pin stabilizing the metal sheet adjacent the stationary platen.  
   
   
       18 . The bend fixture of  claim 15  wherein the first clamp includes a surface extending generally parallel to the principal portion of the stationary platen and the second clamp includes a surface extending generally parallel to the principal portion of the hinged platen.  
   
   
       19 . The bend fixture of  claim 15  wherein the first clamp is spaced from the second clamp.