Geneva drive

Abstract

A mechanism for prepositioning the input shaft of a bidirectional Geneva drive to effect incremental rotation of the output shaft of the Geneva drive, upon rotation of the input shaft, at a predictable time. The Geneva drive has an input shaft rotatable in opposite directions through active angles which respectively effect rotation of the output shaft. The prepositioning mechanism comprises a member, coupled to the input shaft, and having a pair of spaced, oppositely directed abutment surfaces. A locating pawl is selectively moved to a position to be engaged by one abutment surface when the input shaft is rotated in one direction and the other abutment surface when the input shaft is rotated in the opposite direction to angularly preposition the input shaft at a location from which rotation of such input shaft one of through its respective active angles is accurately predictable. The locating pawl is thereafter moved to disengage the engaged abutment surface so that the input shaft is rotatable through such respective active angle to incrementally rotate the output shaft at a predictable time based on movement of the pawl.

Dependencies are inferred from the claim text.