Screen printing machine and drive system therefor

摘要

A screen printing machine has a carousel rotatable about a central support and carrying a circular arrangement of work-receiving tables. A framework interconnected with the central support carries corresponding screen printing units. Rotation of the carousel causes the work-receiving tables to come into registry with corresponding printing units for screen printing of work carried by the work-receiving tables. Each such unit includes a squeegee support frame pivotal relative to the framework for movement between raised and lowered positions. A screen frame is carried by the squeegee support frame. A squeegee and a scraper blade are supported by a carriage traveling over the squeegee support frame for reciprocal movement over the stencil frame for screen printing of work pieces carried by a corresponding work-receiving table. A cam carried by the framework includes first and second planar surfaces forming an angle <180 DEG between them. A vertical drive shaft, turned by an electric motor, carries at its lower end a drive roller for rolling alternate engagement of the cam surfaces, there being springs for urging the squeegee frame toward its raised position, from which it is driven to the lowered, printing position by drive roller engagement with the cam surfaces. A crank is carried by the upper end of the drive shaft. A connecting rod interconnects the carriage and crank for causing reciprocating movement of the squeegee and the scraper blade upon rotation of the drive shaft.