Abstract: A sewing machine includes upper and lower beams. A thread hooking mechanism is mounted in the lower beam. A needle plate base is mounted to an end of the lower beam. A transmission shaft rotatably extends in the lower beam and has an end extending into the needle plate base. The transmission shaft can be driven by a power source. A driving device is mounted to the end of the lower beam and includes a transmission gear fixed on the end of the transmission shaft, a driven shaft rotatably received in the needle plate base and having an end coupled to the thread hooking mechanism, and a driven gear fixed on the driven shaft and connected to the transmission gear, with the driven shaft and the thread hooking mechanism rotating at a speed higher than the transmission shaft.

Abstract: A sewing machine includes a main frame including a needle seat, a beam, and a head supported by the beam. The head includes elements for sewing operation in association with the needle seat. A fixed seat is fixed to the beam and a rotational seat is fixed to the head to turn therewith. The rotational seat and the fixed seats include aligned axial holes. A shaft sleeve extends from the rotational seat and rotatably extends through the axial hole of the fixed seat. The head and the rotational seat are movable relative to the fixed seat between an operative position allowing sewing operation and an inoperative position angularly spaced from the operative position. A distance between the head and the needle seat is increased when the head is moved from the operative position to the inoperative position, allowing easy insertion and removal of thick materials during a sewing operation.