US Patent 8430274 Foam dispensing assembly

The present invention provides a foam dispensing assembly comprising a liquid piston pump, comprising a liquid cylinder and a liquid piston delimiting a liquid pump chamber, and a liquid inlet and outlet, an air piston pump comprising an air cylinder and an air piston delimiting an air pump chamber, and an air inlet and 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. The invention is characterized in that said air cylinder is formed by a cylindrical skirt of said actuation button, and said air piston is at least partially formed by a cylindrical extension of said securing collar and in that said air chamber at least partially surrounds said liquid chamber.