Patent ID: 7780042

Claim:
A fluid dispenser pump comprising: a pump body; a pump chamber; at least a first piston that slides in said pump chamber between a rest position and an actuated position so as to dispense the fluid; and a dispenser orifice; said pump chamber including an inlet valve that separates the pump chamber from a channel that extends towards a fluid reservoir, a bypass being provided between said channel and said pump chamber, said bypass being disposed upstream from said inlet valve, wherein said bypass connects the pump chamber to the reservoir when the piston is in its actuated position, each time the pump is actuated; wherein said first piston is secured to a hollow rod that forms, at least in part, said channel, said inlet valve, and said bypass; wherein said hollow rod includes, in or on its outside surface, between said bypass and said first piston, a passage that connects the pump chamber and the bypass when the first piston is in its actuated position, regardless of the deformation of the components of the pump under the effect of the suction generated on each actuation; and wherein the bypass is a lateral borehole formed in a valve seat upstream of the valve inlet.