Apparatus and method for screen tensioning

Abstract

A screen fabric frame is disclosed including a locking strip and a frame member. The frame member includes a locking strip groove extending at least a portion of a length of the frame member. The locking strip groove includes a central groove configured to receive the locking strip, a minor side groove having a minor depth, and a major side groove distal the central groove, the major side groove having a major depth greater than minor depth of the minor side groove.

1 . A frame for stretching screen fabric, the frame comprising:
 a frame member including a locking strip groove extending at least a portion of a length of the frame member, the locking strip groove including
 a first upper edge, a first groove wall, and a first upper surface between the first upper edge and the first groove wall, 
 a second upper edge, a second groove wall, and a second upper surface between the second upper edge and the second groove wall, 
 a base surface between the first groove wall and the second groove wall, and 
 a side chamber formed between the second upper surface and a portion of the base surface; and 
   a locking strip having a first edge and a second edge, the screen fabric folded around the locking strip, the locking strip sized for
 insertion of the second edge of the locking strip into the side groove, 
 rotation of the first edge of the locking strip past the first upper edge into the groove, and 
 formation of an interference fit of the locking strip between the first upper surface and the base surface of the locking strip groove such that the screen fabric binds between the first upper surface and the base surface. 
   
     
     
         2 . The frame of  claim 1 , wherein a width of the locking strip is less than a distance between the second groove wall and the first upper edge. 
     
     
         3 . The frame of  claim 1 , wherein the locking strip has a triangular cross section. 
     
     
         4 . The frame of  claim 3 , wherein a thickness of the first edge of the locking strip is greater than the height of the first groove wall. 
     
     
         5 . The frame of  claim 1  wherein the locking strip includes one or more longitudinal ridges. 
     
     
         6 . The frame of  claim 1 , wherein a distance between the second groove wall and the first upper edge is greater than a distance between the first groove wall and the second upper edge. 
     
     
         7 . The frame of  claim 1  wherein a width of the locking strip is greater than a distance between the first groove wall and the second upper edge. 
     
     
         8 . A system for tensioning a silkscreen panel on a silkscreen frame having a locking strip groove, the system comprising:
 an elongated locking strip of stiff material configured to flex and having a triangular cross section, the locking strip having a first edge and a second edge;   a screen fabric folded around the first edge of the locking strip, the locking strip and folded screen fabric configured for insertion of the second edge into the locking strip groove, the locking strip sized to form an interference fit between an upper edge and a base surface of the locking strip groove such that the first edge of the locking strip bears against the upper edge of the locking strip groove.   
     
     
         9 . The system of  claim 8  wherein the locking strip is sized to bind the screen fabric between a base surface and a sloping upper surface of the locking strip groove. 
     
     
         10 . The system of  claim 8 , wherein the locking strip includes one or more longitudinal ridges. 
     
     
         11 . The system of  claim 8 , wherein the cross section of the locking strip includes a complex curve. 
     
     
         12 . The system of  claim 8 , wherein a width between the first edge and the second edge of the locking strip is less than a distance between the upper edge and a side groove depth of a locking strip groove disposed in the silkscreen frame. 
     
     
         13 . The system of  claim 8  wherein a height of the first edge of the locking strip is greater than a height of the second edge of the locking strip. 
     
     
         14 . The system of  claim 8  wherein the flex of the locking strip provides for a twist about a roll axis along a longitudinal dimension during insertion into the locking strip groove, the twist permitting short portions of the locking strip to be progressively inserted into the locking strip groove along the length of the locking strip. 
     
     
         15 . A method for tensioning a screen fabric on a frame, the method comprising:
 folding the screen fabric around a locking strip having a triangular cross section, the triangular locking strip configured to twist about a roll axis and flex along a longitudinal dimension;   inserting a first edge of the triangular locking strip and folded screen fabric into a locking strip groove disposed longitudinally along a frame member;   twisting the triangular locking strip and folded screen fabric about the longitudinal dimension to rotate a portion of a second edge of the triangular locking strip and folded screen fabric into the locking strip groove;   rotating the remaining length of the triangular locking strip and folded screen fabric into the locking strip groove to orient a surface of the triangular locking strip about parallel to a base surface of the locking strip groove;   applying a tension to the screen fabric;   urging the second edge of the triangular locking strip to bear against an upper edge of the locking strip groove using the applied tension.   
     
     
         16 . The method of  claim 15 , wherein applying a tension to the screen fabric comprises rotating the frame member. 
     
     
         17 . The method of  claim 15 , wherein applying a tension to the screen fabric comprises translating the frame member. 
     
     
         18 . The method of  claim 15 , further comprising binding the screen fabric between triangular locking strip and the base surface and an upper surface of the locking strip groove. 
     
     
         19 . The method of  claim 15 , wherein twisting the triangular locking strip and folded screen fabric further comprises progressively working along the length of the triangular locking strip to rotate portions of the second edge into the locking strip groove a little at a time. 
     
     
         20 . The method of  claim 15 , further comprising wedging the second edge of the triangular locking strip between an upper surface and the base surface of the locking strip groove, providing pinching of the screen fabric.