Yarn feeding apparatus for circular knitting machines

Abstract

A yarn feeding apparatus for circular knitting machines includes a yarn feeding body and a transmission shaft driven by the yarn feeding body. The transmission shaft is coupled with at least one yarn feeding wheel freely rotating against the transmission shaft. The yarn feeding body includes at least one guiding unit which is drawn by a yarn to turn and move reciprocally between a yarn supply position and a yarn supply stopped position. The transmission shaft is coupled with at least one transmission mechanism driven by the transmission shaft. The yarn feeding wheel includes at least one wedge member corresponding to the transmission mechanism. The wedge member has a first position to separate from the transmission mechanism and a second position pushed by the guiding unit on a motion track to couple with the transmission mechanism to drive the yarn feeding wheel to rotate synchronously with the transmission shaft.

What is claimed is: 
     
         1 . A yarn feeding apparatus for circular knitting machines, comprising a yarn feeding body and a transmission shaft driven by the yarn feeding body, the yarn feeding body including at least one guiding unit drawn by a yarn to turn and move reciprocally on a motion track relative to the transmission shaft between a yarn supply position and a yarn supply stopped position;
 wherein the transmission shaft is movably coupled with at least one yarn feeding wheel which freely rotates against the transmission shaft, the transmission shaft being coupled with at least one transmission mechanism driven by the transmission shaft, the yarn feeding wheel including at least one wedge member corresponding to the transmission mechanism, the wedge member including a first position to separate from the transmission mechanism and a second position pushed by the guiding unit on the motion track to couple with the transmission mechanism to drive the yarn feeding wheel to rotate synchronously with the transmission shaft.   
     
     
         2 . The yarn feeding apparatus of  claim 1 , wherein the wedge member includes a wedge portion to wedge in the transmission mechanism and an action strut pushed by the guiding unit. 
     
     
         3 . The yarn feeding apparatus of  claim 2 , wherein the guiding unit includes a pressing section to push the action strut, the action strut including a drawing surface drawn by the pressing section to move the wedge member to the second position. 
     
     
         4 . The yarn feeding apparatus of  claim 2 , wherein the guiding unit includes a pushing section to push the action strut, the action strut including a butting surface butted by the pushing section to move the wedge member to the first position. 
     
     
         5 . The yarn feeding apparatus of  claim 1 , wherein the transmission mechanism includes a plurality of ratchets, the wedge portion being a detent corresponding to the plurality of ratchets. 
     
     
         6 . The yarn feeding apparatus of  claim 1 , wherein the yarn feeding body further includes a friction plate in contact with the yarn feeding wheel regularly. 
     
     
         7 . The yarn feeding apparatus of  claim 1 , wherein the yarn feeding wheel includes a mounting surface hinged by the wedge member, a cover plate covering the mounting surface and a gap formed between the cover plate and the mounting surface to receive entry of the guiding unit. 
     
     
         8 . The yarn feeding apparatus of  claim 1 , wherein the yarn feeding wheel includes at least one yarn guiding surface, the guiding unit including at least one yarn guiding ring corresponding to the yarn guiding surface to allow the yarn to thread through and guide the yarn to contact the yarn guiding surface. 
     
     
         9 . The yarn feeding apparatus of  claim 1 , wherein the yarn feeding wheel includes a first yarn guiding surface and a second yarn guiding surface, the guiding unit including a first yarn guiding ring corresponding to the first yarn guiding surface to allow the yarn to thread through and guide the yarn to contact the first yarn guiding surface; the yarn feeding body including an ancillary guiding unit which includes a second yarn guiding ring corresponding to the second yarn guiding surface to allow the yarn to thread through and guide the yarn to contact the second yarn guiding surface.