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:
Jan. 12, 1993
Filed:
May. 07, 1991
Takayoshi Shinohara, Nagano, JP;
Toshiyuki Suwa, Nagano, JP;
Nissin Kogyo Kabushiki Kaisha, Nagano, JP;
Abstract
A vacuum booster includes a booster piston having a front surface facing a vacuum chamber, a diaphragm superposed on the rear surface of the booster piston and having a rear surface facing a working chamber adapted to be selectively put into communication with the vacuum chamber or the atmosphere, a piston boss carried on a central portion of the rear wall of the booster shell for a longitudinal reciprocal movement and provided with an annular step with which an inner peripheral bead of the diaphragm engages from the rear, and an annular stopper retained on the piston boss to abut against the inner peripheral bead from the rear. The stopper includes an annular retaining portion at an outer periphery thereof to project forwardly which has a curved front end, and the inner peripheral bead of the diaphragm is formed into a ring shape projecting rearwardly to have its outer periphery engaged with the stopper retaining portion. The curved front end of the retaining portion serves as a center about which the diaphragm is deflected toward the working chamber and thus avoids any damage to the diaphragm. When the diaphragm is deflected toward the working chamber, its inner peripheral bead can be urged radially inwardly by the retaining portion, thus reducing a load imposed on the bead to separate it away from the step of the piston boss, thereby improving the reliability of the stopper.