Patent ID: 8430274

Claim:
A dispensing assembly mountable on a container for dispensing a foam, comprising: a liquid piston pump, comprising a liquid cylinder and a liquid piston delimiting a liquid pump chamber, and a liquid inlet and a liquid outlet, an air piston pump comprising an air cylinder and an air piston delimiting an air pump chamber, and an air inlet and an air outlet, a common actuation button for actuation of said liquid pump and said air pump, a dispensing channel for mixing and dispensing liquid and air pumped by said liquid and air pump, respectively, and a securing collar for attachment of said dispensing assembly to a container, wherein said air cylinder is formed by a cylindrical skirt of said actuation button, and said air piston is formed by a cylindrical extension of said securing collar, wherein the cylindrical skirt at least partially surrounds the cylindrical extension, and wherein a piston seal is arranged between the cylindrical extension and the skirt, wherein said piston seal is displaceable with respect to said cylindrical extension in by an actuation movement of the common actuation button with respect to the cylindrical extension between at least a closed position in which the piston seal provides an air tight seal between environmental air and said air pump chamber, and an open position in which introduction of air into the air pump chamber between the cylindrical extension and the skirt is possible.