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:
Feb. 12, 1980
Filed:
Apr. 24, 1978
Michel Grenier, Dampmart, FR;
WABCO Westinghouse, Freinville-Sevran, FR;
Abstract
A dynamic/friction brake blending valve device having a piston assembly arranged to operate a pressure regulator via which brake cylinder pressure is controlled. Associated with the relay valve device is an electrical circuit comprising a differential amplifier subject in a first mode of operation to a brake command signal and a dynamic brake signal representing the degree of dynamic brake effort being provided in response to the brake command. An error signal resulting from comparison of the brake command and dynamic brake signals is converted by a transducer to a corresponding fluid pressure that is supplied to a chamber formed between first and second differential pistons of the piston assembly to actuate the pressure regulator and thereby produce brake cylinder pressure corresponding to the deficiency of the dynamic brake. Another chamber formed between the second piston and a third differential piston of the piston assembly may be connected to a pneumatic control valve device that operates in response to brake pipe pressure variations, which may be made independently of the brake command signal, to provide apparatus for obtaining a back-up or emergency brake application in the event an electrical malfunction renders the differential amplifier inoperative. In a second mode of operation, the differential amplifier error signal is replaced by the dynamic brake signal and the brake pipe pressure is adjusted simultaneously with the brake command so as to correspond thereto. In this respect, the brake blending valve device itself accomplishes the comparison function provided by the differential amplifier in the first mode of operation, in order to supplement the dynamic brake with friction brake effort corresponding to any deficiency of the dynamic brake which may arise.