Cam transmission mechanism of quilt sewing machine

The invention discloses a cam transmission mechanism of a quilt sewing machine. The cam transmission mechanism comprises a rack, a lifting crossbeam and a first rotating shaft, the first rotating shaft is connected with the upper portion of the rack, guide shafts are correspondingly arranged on two sidewalls of the rack, the lifting crossbeam moves vertically along the guide shafts, the end of the lifting crossbeam is connected with a cam through a connecting rod, the cam is arranged on at the position, below the lifting crossbeam, of the corresponding sidewall of the rack, the cam drives a second connecting plate to move vertically through a first connecting plate, one end of the first connecting plate is rotationally connected with the corresponding sidewall of the rack, the other end of the first connecting plate is connected with one end of the second connecting plate, the other end of the second connecting plate is connected with a chain, and the chain is wound around a first chain wheel connected with the first rotating shaft and is fixedly connected with the corresponding sidewall of the rack through an elastic device. The lifting crossbeam drives the first rotating shaft to work while completing work, a thread on a needle head is picked up through a support on the first rotating shaft, and the automation degree of the quilt sewing machine is effectively improved.