Patent ID: 7155941

Claim:
A knitting machine having a variable stitch mechanism comprising a stitch cam, said stitch mechanism comprising: a common retracting cam surface to engage with at least one of butts projecting from a needle bed and set at different levels of full height and half height under a pressing action of a presser arranged in a carriage, so as to retract both a butt of half height of a small stitch forming needle and a butt of full height of a large stitch forming needle, a stitch size determining cam surface for a small-sized stitch which is formed to extend continuously from the common retracting cam surface, a stitch size determining cam surface for a large-sized stitch which is engageable with the butt of full height formed at a trailing side with respect to the stitch size determining cam surface for the small-sized stitch, and a receiving cam to restrict excessive retraction of each of the butts of the different-sized stitches forming needles beyond the stitch size determining cam surface corresponding to the butt of the stitch forming needle, whereby the small-sized stitch and the large-sized stitch are formed in the same course; wherein said stitch cam comprising: a first cam in which a stitch size determining cam surface for a large-sized stitch and a receiving cam surface to engage with a butt of the needle for forming the large-sized stitch are formed in the same phase as the stitch size determining cam surface, and a second cam having a common retracting cam surface and a stitch size determining cam surface for a small-sized stitch extending continuously from the common retracting cam surface, wherein a receiving cam surface engageable with a butt of the needle for forming the small-sized stitch is formed in the same phase as the stitch size determining cam surface for the small-sized stitch, drive means for driving the first cam in a front-and-back direction, and drive means for driving the second cam in the front-and-back direction, and wherein the second cam is supported on the first cam in such a manner that when the first cam is shifted in the front-and-back direction by the drive means of the first cam, the second cam is shifted together in the front-and-back direction and also shifted relative thereto in the front-and-back direction by the drive means of the second cam so that the stitch size determining cam surface provided in the second cam can be displaced with respect to the stitch size determining cam surface provided in the first cam.