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:
Nov. 03, 1987
Filed:
Oct. 11, 1985
WABCO Westinghouse Equipements Ferroviaires S.A., Freinville-Sevran, FR;
Abstract
A dual-piston hydraulic brake master cylinder includes a large hydraulic piston which supplies an initial large brake fluid volume and a small hydraulic piston which continues to supply brake fluid to the brakes when the large piston stops moving forward in its cylinder at higher brake pressures. The small, central hydraulic piston is connected to the end of a piston rod extension of a pneumatic booster piston. The large piston surrounds the small piston and opens a reservoir line tilt-valve in the piston retracted position. A passageway between the large and small hydraulic chambers is open in the retracted position to allow communication of braking fluid therebetween. During brake actuation a seal arrangement interrupts this communication. The large and small hydraulic chambers supply the brake circuits through delivery passages.