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, 1985
Filed:
Nov. 05, 1982
Keith W Langley, Bath, GB;
Jack Washbourn, Frazer, PA (US);
Abstract
A railway vehicle braking system is provided with a 'snow brake' control arrangement which is used in freezing temperatures to apply a small brake force for prolonged periods to engage blocks or shoes on the vehicle wheels to reduce icing. The 'snow brake' control arrangement itself includes an pneumatic valve system that includes a relay valve unit which, in a first mode, provides 'snow brake' operation and, in a second mode, provides for application of brake pressure from the straight air pipe to the brake cylinders. A solenoid valve, actuated responsive to energization of a control solenoid by a snow brake control switch, controls connection of 'snow brake' pressure from a supply reservoir to a control chamber of the relay valve. When the straight air pipe is pressurized responsive to call for service or emergency braking, the solenoid is de-energized and the control chamber vents to atmosphere through the solenoid valve. The relay valve provides a delay in re-energization of the solenoid, and hence in effecting reinstatement of 'snow brake' operation, so that the slack adjusters can make whatever slack adjustment in the brakes that is necessary.