Patent ID: 6899698

Claim:
An automatic one-way clutch mechanism for use in an incrementing mechanism having: a tubular body; a driving member rotatably and slidably mounted within the tubular body; an elongate element mounted within the tubular body and arranged to be advanced in one direction with respect to the tubular body upon operation of the driving member; which one-way clutch mechanism comprises: a channel extending along the elongate element; a generally conical surface formed internally on the driving member and surrounding the elongate element; a blocking clutch member located in the channel and engageable with the conical surface; and a freeing mechanism adapted to disengage the clutch by lifting the clutch member out af engagement with the conical surface so as to disconnect the driving member from said elongate element, which freeing mechanism comprises: a pressure component held against rotation with respect to the elongate element and arranged to engage the clutch member; a spring acting on said component to urge the component away from its clutch disengaging position; and two sets of inter-engageable teeth formed respectively around the driving member and around the pressure component; whereby rotation of the driving member with respect to the pressure component successively lifts said component against the action of the spring and then releases said component, the lifting serving to move the clutch member out of engagement with the conical surface and allows the spring to move the pressure component to a position where the clutch member engages said surface, through the inter-action of the teeth riding over each other.