Patent ID: 6064829
Filing Date: 2000-05-16
Classification: G03B

Abstract:
A counter device for a sheet photo film pack, said sheet photo film pack including a pack housing for containing a stack of plural sheet photo film units, said counter device comprising:a counter chamber formed in said pack housing;a counter disk, contained in said counter chamber in a rotatable manner, and having first and second faces;a train of counter numerals arranged on said first face in an arc-shaped manner at a predetermined pitch;plural stepping claws, disposed on said first face to project in a thickness direction of said counter disk, arranged in an arc-shaped manner at said predetermined pitch, and rotationally shifted by an external mechanical shift signal in a predetermined stepping direction, for setting each one of said counter numerals in a predetermined index position adapted to indicate a number of one of exposed and unexposed ones of said sheet photo film units;an erect surface, formed on each one of said stepping claws, positioned thereon backwards to said stepping direction, erect in said thickness direction of said counter disk, and pushed in said stepping direction by a portion of an external counter advance mechanism, for receiving said shift signal;a guide inclined surface, formed on each one of said stepping claws, positioned thereon in said stepping direction, and inclined with reference to said thickness direction of said counter disk, for guiding said portion of said counter advance mechanism moved in reverse to said stepping direction, to allow engaging said portion with said erect surface upon passing said stepping claws;wherein said sheet photo film pack is used with a pack holder, and said pack holder includes:a holder housing for containing said sheet photo film pack; andsaid counter advance mechanism, disposed in said holder housing, and actuated in response to an operation associated with use of each one of said sheet photo film units, for generating said shift signal;wherein said portion of said counter advance mechanism is a spring plate, said spring plate includes a bend end engageable with said stepping claws, said bend end has an inclined side extended with an inclination consistent with said guide inclined surface, and said spring plate moves back and forth for one time for rotating said counter disk by said predetermined pitch; anda ratchet mechanism for preventing said counter disk from rotating in reverse to said stepping direction when said counter numerals are set in said index position;wherein said ratchet mechanism includes:plural ratchet claws, disposed on said second face to project from said counter disk, and arranged in an arc-shaped manner at said predetermined pitch; anda push plate, disposed in said counter chamber in a movable manner, confronted with said second face, for blocking rotation of said ratchet claws in reverse to said stepping direction.