The present invention relates to a flat knitting machine wherein there is disposed a transfer lock which permits needles to be selectively guided into a loop transfer path or a loop receiving path, in same phase as a knitting lock which permits needles to be selectively guided to three positions, knit, tucking, and welt, so that needles are allowed to knit, tuck, welt or transfer within an operative zone in same phase as the knitting lock in the widthwise direction of a carriage.
A prior art disclosure relevant to such type of machine is found in Published UK Patent Application GB No. 2080344A, which discloses a cam support comprising at least one arrangement of lifting cams comprising two lifting cams arranged immediately one after the other and each comprising two opposed ramps and a third lifting cam disposed between the adjacent ramps of the two first cams, an empty space being provided below the third cam, said space being connected to two channels limited on one side by the adjacent ramps of the two first cams, so that a pin, respectively of a needle, selected before the arrival of an outer end of said first cams, is entrained by one of the said first cams, in the direction of movement of the cam-support and by the third cam and operates for shaping, whereas a pin, respectively of a needle, selected when said empty space arrives approximately opposite said pin, respectively of a needle, is not entrained by the third cam and operates for picking up.
In this prior-art system, however, the cam for pushing a front butt (which is disposed on a needle, while a rear butt is disposed on a pin or jack) to put the needle into a path of transferring operation is movable, and its upper surface constitutes a cam face which will act on the back of the front butt to lift the needle to the transferring path, whereas its underside constitutes a cam face for pushing the front of the front butt to lower the needle into a stitch receiving path. And for the purpose of lowering the needle from the transferring path, there is disposed above said movable cam a guide cam which is fixed. This guide cam acts on the front of the front butt to lower the needle.
Therefore, to the extent that such fixed guide cam for pushing the abutment surface of the front butt to lower the needle from the transfer path is disposed above said movable cam for putting the needle into the transfer path, the prior-art cam system involves larger lengths of cam plate and needle bed in the longitudinal direction of the needle trick, and also an increase in the length of needle tricks.