Patent ID: 8292130

Claim:
A fluid dispenser pump comprising a pump body; a piston that slides in leaktight manner in said pump body between a rest position and an actuated position, said piston secured to an actuator rod that extends axially out from said pump body; a ferrule mounted on a top edge of said pump body, said ferrule defines the rest position of said piston; said ferrule co-operates in leaktight manner with the actuator rod while the actuator rod moves the piston between the rest position and an intermediate position, and said ferrule co-operates in non-leaktight manner with the actuator rod while the actuator rod ( 30 ) moves between said intermediate position and the actuated position, so as to enable the pump to be vented, said piston not being in contact with said ferrule, when in the rest position; and said ferrule comprises a radial flange that bears against the top end edge of the pump body and an axial sleeve that extends inside said pump body, at least in part, and having a bottom end that forms a contact zone that co-operates with said actuator rod.