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. 21, 1993
Filed:
Jun. 01, 1992
Frank W Brooks, Sr, Dayton, OH (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A wheel cylinder has a body, pistons, boots and seals. A screw assembly positioned between the two pistons holds the pistons apart to maintain the specified clearance between the brake linings and the brake drum while the brake is released. If a predetermined amount of outward movement of the pistons occurs during brake actuation, the screw rotates with further piston outward movement. When the brake is released, the pistons return inwardly, and the screw is locked against reverse rotation by means of a clutch, preventing the pistons from returning more than the prior predetermined amount of outward movement before screw rotation began. A clutch seal on an extension of one clutch member seals in a piston cylinder section. The other clutch member is formed on that piston next to one end of the cylinder section. The cylinder section axially beyond the seal is vented to atmosphere. A cross pin extends across a cavity in the one clutch member, is mounted in slots formed in the one clutch member and in the screw, and permits limited movements of the pin axially of the wheel cylinder. The space between the closed sides of the one clutch member slots, combined in series with the space between the closed slides of the screw slot, define the allowable amount of axial movement between the two pistons without disengaging the adjuster clutch under excessively high pressure conditions. This allowable amount of axial movement is greater than that occurring in any one cycle of the brake.