POSITIVE ENGAGEMENT CLUTCH WITH SOFT ENGAGEMENT MOTION

摘要

ABSTRACT OF THE DISCLOSURETo place a driven shaft in accurate angular alignmentwith respect to a continuously rotating driving shaft or selective-ly, with respect to a fixed reference, the fixed reference isformed as a housing, the driving shaft has a disk with a camtrack attached thereto, and the housing likewise has a diskwith a cam track. The driven shaft has an engagement pin connect-ed thereto, axially slidable and engageable, respectively,with the cam tracks of the driving shaft, or of the housing.The cam tracks are arranged to carry along and gradually acceleratethe pin coupled to the driven shaft until the pin locks at apredetermined position in the cam track to define the relativeangular position of driving shaft and driven shaft; upon differentaxial movement, the engagement pin is permitted to slide out ofengagement with the cam track disk coupled to the driving shaftand engage a similar, and stationary cam track on the housing,again formed with a stop or rest position which again determinesthe angular relationship of the driven shaft with respect tothe housing, and hence with respect to the reference. Axialsliding movement of the engagement pin is controlled by pneumaticpressure acting on spring-loaded pistons. The clutch isparticularly useful in connection with printing machinery,especially rotary screen printing machinery, to provide for accuratealignment of intermittently operating printing stencil cylinderswith respect to the instantaneous angular position of the machinedrive shaft.