Synchronous belt and pulley drive

Abstract

A synchronous belt and pulley drive in which the drive between spaced pulleys is primarily by frictional contact of a belt on the pulley peripheries; synchronization is insured by providing spaced teeth on the belt which teeth are accommodated by tooth gaps in the periphery of the pulleys. The drive is further characterized by matching the pitch of the driveR pulley with the belt pitch under a first tension and matching the pitch of the driveN pulley with the belt pitch under a second tension, wherein the first tension is different and usually greater than the second tension.

I claim: .[.1. A synchronous belt and pulley drive comprising: 
     
        and sides of the tooth gaps. .Iaddend. .Iadd. 13.  A synchronous belt and pulley drive comprising: a driver pulley and a driven pulley;   said pulleys being spaced from one another and each having bearing surfaces separated circumferentially by a plurality of uniformly spaced recesses for accommodating belt teeth, an endless belt engaging the pulleys and having on its inner surface a plurality of spaced teeth, the spacing between adjacent teeth being uniform in the circumferential direction when the belt is free of tension,   the drive between said respective pulleys being primarily by friction between the belt and said bearing surfaces, the relationship of belt teeth and pulley recesses insuring synchronization of the drive,   said pulley recesses being circumferentially wider and radially deeper than said belt teeth,   the circumferential extent of the bearing surfaces being substantially greater than the circumferential width of the recesses,   the circumferential extent of the bearing surfaces on the driver pulley being matched to the spacing between adjacent belt teeth when the belt is stretched under a first tension, and   the circumferential extent of the bearing surfaces on the driven pulley being matched to the spacing between adjacent belt teeth when the belt is under a second and different tension. .Iaddend.