Sewing machine drive mechanism, has transmission link between upper and looper shafts through connecting control belt with paired chain wheels and cogwheels in compact assembly operating with low noise and vibration

摘要

The drive mechanism for a sewing machine has a chain wheel (38) fitted at the upper shaft (2) and a further chain wheel (52) mounted close to and parallel to the axis of the looper shaft (6). A control belt (56) is around both chain wheels. A cogwheel (54), in one piece with the second chain wheel (52), meshes with a cogwheel (44) keyed to the looper shaft (6). The control belt (56) gives the transmission link between the upper (2) and looper (6) shafts, and they are interconnected through the paired chain wheels (38,52) and cogwheels (44,54). The second chain wheel (52) rotates on an eccentric axis (46) mounted to the machine frame (30), where the direction of eccentricity can be adjusted to vary the gap between the axes of both cogwheels (44,54).