US Patent 7685795 Grip belt drive system

The present invention describes an improved grip belt drive system for use in sealing machines used to wrap articles in thermoplastic film. Briefly, a timing belt is used in place of the traditional flat or V belt. The presence of teeth on the pulleys, coupled with the use of a timing belt eliminates the possibility of slippage between the belt and the pulleys. To protect the system in the case of a film jam or misplaced article, a torque-limiting mechanism is included, which disengages the drive system if there is excessive counterforce. Furthermore, the outer surface of timing belt contains a pattern, which when mated with a second belt having the same or a complementary pattern, meshes in such a way so that the two belts are positively locked in both the longitudinal and transverse directions.