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. 29, 1991
Filed:
Jul. 03, 1989
John R Coleman, Dayton, OH (US);
General Motors Corporation, Detroit, MI (US);
Abstract
A dual master cylinder for a vehicle brake system includes a housing having a housing bore with a open end and a closed end. The open end has a piston stop. Two pistons are reciprocably received in the housing bore and define therewith a first pressurizing chamber between the pistons and a second pressurizing chamber between the second piston and the housing bore closed end. Each piston has a piston cavity opening into the respective pressurizing chamber. A first locator member and a second locator member are respectively received in the pressurizing chambers and slidably mounted in the piston cavities of the respective pistons. The first locator member projects into engagement with the rear wall of the second piston and the second locator member projects into engagement with the housing to establish the pistons at respective normal rest positions enabling fluid communication through the port between the fluid reservoir and the respective chambers. A detent associated with each of the locator members permit the collapse of the locator members within the respective piston cavity upon a first occurring forward movement of the pistons forward of the respective normal rest positions, and further acts to retain the locator members in their respective collapsed states. With the locator members remaining in the cavities, the pistons are freed for fore and aft reciprocable movement within the housing during subsequent operation of the master cylinder.