Bobbin fixing device

Abstract

In a bobbin fixing device, a collet type chuck having claw members is mounted to the upper portion of a rotary hollow shaft and a bobbin slip-off preventing member 27 which comprises a substantially U-shaped claw expansion portion having arcuate projection portions for expanding the interval between the above claw members is inserted between the claw members of the above collet type chuck to secure a bobbin to the rotary shaft without fail at the time of winding off a wire material and facilitate the exchange of the bobbin. The claw expansion portion of the bobbin slip-off preventing member is fitted in guide grooves formed in the claw members to expand the interval between the claw members so as to press the upper end portions of the bobbin and rotatably hold the bobbin when the bobbin is to be mounted and holding force is not applied to the bobbin by taking out the bobbin slip-off preventing member when the bobbin is to be exchanged.

What is claimed is:  
     
         1 . A bobbin fixing device comprising a rotary hollow shaft, having a positioning plate for restricting the position of the lower flange of a bobbin, for accepting the bobbin and a fixed shaft connected to the rotary shaft by bearings, wherein 
 the device further comprises a collet type chuck which is mounted to the upper portion of the rotary shaft and a bobbin slip-off preventing member which is inserted into the space between the claw members of the collet type chuck to expand the interval between the claw members.    
     
     
         2 . The bobbin fixing device of  claim 1 , wherein the bobbin slip-off preventing member is a spring member composed of a claw expansion portion having tapered portions for expanding the interval between the claw members and securing portions for sandwiching the rotary shaft from both sides.  
     
     
         3 . The bobbin fixing device of  claim 2 , wherein the bobbin slip-off preventing member is a spring member composed of (1) a substantially U-shaped claw expansion portion having arcuate projecting portions projecting outward for expanding the interval between the claw members at the center of each side, (2) substantially ring grip portions, connected to the both ends of the claw expansion portion, for holding the bobbin slip-off preventing member, and (3) securing portions, extending from the grip portions in parallel to the claw expansion portion, for sandwiching the rotary shaft from both sides.  
     
     
         4 . The bobbin fixing device of any one of  claims 1  to  3 , wherein guide grooves for accepting the bobbin slip-off preventing member are formed in the inner wall of the collet type chuck.  
     
     
         5 . The bobbin fixing device of any one of  claims 1  to  4 , wherein cut-out portions are formed in the upper portions of the rotary shaft so that the upper portions of the claw members are exposed from the respective cut-out portions to fix the bobbin.