One-way clutch mechanisms and injector devices

An injector device comprising:

• a medicament-containing tube;
• a piston mounted within the tube to eject medicament therefrom;
• and
• an incrementing mechanism for said piston,
• said incrementing mechanism comprising:
• 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, the elongate member engaging with said piston;
• and
• an automatic one-way clutch mechanism arranged to effect coupling between the driving member and the elongate element when the driving member is moved in one direction with respect to the tubular body and arranged not to drive the elongate element when the driving member is moved in the other direction with respect to the tubular body;
• said automatic clutch mechanism comprising:
• a channel extending along the elongate element;
• a generally conical surface formed internally on the driving member and surrounding the elongated 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 of engagement with the conical surface so as to disconnect the driving member from said elongate element;
• said freeing mechanism comprising:
• 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.