Patent ID: 7735693

Claim:
Precompression pump comprising: a cylinder which defines a pump body and in whose interior there is a pump chamber, an inlet valve arranged at the bottom of said cylinder, a piston presenting a lower outwardly flaring lip seal for sliding engagement within said cylinder, and an inwardly flaring lip seal which rims a central aperture of said piston, a pump plunger rod for sliding engagement in said central aperture and which is hollow and has an interior communication passage for communicating said pump chamber with the outside, a securement device for attaching said cylinder to a container and defining an upper retention cover, a first elastic member housed in said cylinder and a second elastic member, said second elastic member defining a first height, measured according to a longitudinal axis of the pump, wherein said piston has an upper cylindrical wall partially surrounding an upper part of said pump plunger rod, said upper cylindrical wall guiding said upper part and defining a guiding height, measured according to the longitudinal axis, wherein said second elastic member has an upper bearing point directly applied on said plunger rod, in which said upper bearing point is above said upper retention cover, and in that said first height and said guiding height are at least partially overlapped.