UNIDIRECTIONAL GEAR TRANSMISSION

摘要

A unidirectional gear transmission of reduced axial thickness advantageously employed in timepieces is adapted to be driven by a stepping motor. The driving gear is provided with an alternating pattern of teeth having a first thickness and spacing and sets of two teeth having greater thickness and spacing. The driven gear is provided with an alternating pattern of teeth corresponding to the first thickness teeth of the driving gear and two spaces corresponding to the greater thickness teeth of the driving gear separated by a single tooth. Regular stepping rotation in either sense can be transmitted from the driving gear to the driven gear, but transmission of rotation from driven to driving gear is prevented.