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. 14, 1992
Filed:
May. 18, 1990
Nicola Tristano, Matera, IT;
Angelantonio Errico, Giovinazzo, IT;
Bendix Altecna S.p.A., Modugno, IT;
Abstract
The invention relates to a wheel cylinder for a drum brake, comprising a body (2) provided with a longitudinal bore, two pistons (4,6) sliding in opposite directions outwards in the bore under the action of a pressurized fluid introduced between the pistons against the return springs of the shoes of the brake, and a mechanism limiting the return travel of the pistons when the pressure is released. According to the invention, the mechanism limiting the travel consists of two resilient rings (16, 18), at the outer periphery of each of which a friction mechanism (20, 22) is disposed, and which are disposed, respectively, in an annular groove (24, 26) made in each of the pistons so as to provide a specific axial clearance (d) between a radial wall of the groove and the adjacent side of an assembly consisting of the resilient ring and the friction mechanism, this assembly being provided in order to resist the return springs of the brake shoes in a drum brake. The resilient rings (16, 18) are in the form of an open retainer ring with variable thickness about its perimeter so as to effect a substantially uniform pressure over its outer periphery against the inner surface of the cylinder.