Unidirectional gear transmission
AssigneeSociete Suisse pour l'Industrie Horlogere Management Services S.A.
InventorCyril Vuilleumier
Life of this patent
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Abstract
A unidirectional gear transmission of reduced axial thickness advantageou 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.
Claims7
A unidirectional gear transmission comprising a driving gear and a driven gear, the driving gear being rotated in predetermined fixed steps and being provided with at least one first set of driving teeth of a first thickness separated by a first tooth space and at least one second set of two driving teeth of a second and greater thickness separated by a second and greater tooth space, said first and second sets being alternately arranged about the driving gear, and the driven gear being provided with teeth separated by an appropriate space adapted to mesh with, and be driven by, said driving gear teeth of said first thickness, but having at least one set of two greater tooth spaces on said driven gear, greater in size than said appropriate space, adapted to mesh with, and be driven by, said teeth of greater thickness whereby stepwise transmission of rotation from said driving gear to said driven gear may be realised in both rotation senses and transmission of rotation from said driven gear to said driving gear between steps is prevented by butting of teeth of said driven gear against teeth of greater thickness of said driving gear.
Dependencies are inferred from the claim text.