The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 27, 1988
Filed:
Jun. 19, 1987
Robert Nissels, Vallieres, FR;
Berthoud, S.A., Belleville Sur Saone, FR;
Abstract
A piston pump having a flexible rolling membrane which seals the piston from the cylinder wherein the piston is designed to include an upper portion which is spaced inwardly from the cylinder wall so as to form a cavity which communicates through channels and seals carried by the lower portion of the piston in such a manner that the lower portion of the flexible membrane is depressed between the upper portion of the piston face and the cylinder walls during an intake stroke as the cavity is subjected to a decreased pressure and which decreased pressure is removed from the membrane during a discharge stroke of the piston. In the preferred embodiment, the membrane is secured to the upper surface of the piston by a cup-shaped element which protects the membrane from materials within the cylinder.