Patent ID: 6554588
Filing Date: 2003-04-29
Classification: F04B

Abstract:
Composite piston (30, 30a) for a vibration pump with an electromagnetic drive comprising:a core (32, 32a) which is made of ferromagnetic metallic material limited in extension to the piston zone intended to perform the magnetic driving function, a piston (34, 34a) which is made of non-metallic and non-ferromagnetic material and performs the pumping function, the metal core (32, 32a) performing the magnetic moving function being made of stainless steel possessing ferromagnetic properties, characterized in that: the piston (34, 34a) performing the pumping function is made of a plastic material moulded on the metal core (32, 32a) and inserted with a part thereof, consisting of a cylindrical blank (36, 36a) in an axial bore (40, 40a) provided with an upset bottom rim (41) which rests against a bottom side of the metal core (32) and a projecting collar (42) which is housed inside a circumferential cavity (44) of the said metal core (32).