Patent ID: 7108160

Claim:
A manually operable pump comprising: a cup-shaped body defining an intake and compression chamber for a creamy substance, the cup-shaped body having a hole through which the creamy substance enters into the chamber at a first end of the cup-shaped body, the cup-shaped body having a unidirectional valve which intercepts the creamy substance; a hollow stem having a portion which projects from the cup-shaped body and another portion which extends into said chamber; a piston mounted on the hollow stem and sealing both against the hollow stem and against the opposing surface of said chamber, said piston bounding said chamber at a second end and being movable between a position in which said piston sealedly closes a hole provided in the hollow stem and communicating with a cavity of the hollow stem, and a position in which the hollow stem leaves said hole free to enable the creamy substance to flow from said chamber to the outside of the pump through the cavity; a sleeve provided rigid with the cup-shaped body on the outside of the chamber and having an opening through which said hollow stem extends and is axially slidable; and a spring acting between the cup-shaped body and the hollow stem to urge the hollow stem towards the sleeve, wherein said sleeve includes a first tubular lip against which said piston rests and seals when the pump is in a rest position, and a second tubular lip against which a first annular collar projecting from the hollow stem outside the chamber rests and seals when the pump is in the rest position.