Empty/load changeover valve for railway car
First Claim
1. For use in a railway vehicle brake control system including a brake pipe charged to a certain chosen pressure, a brake cylinder device, a brake control valve device via which fluid under pressure is supplied to said brake cylinder device and released therefrom in accordance with variation of the fluid pressure in said brake pipe, and sprung and unsprung members, an empty/load changeover valve device mounted on one of the sprung and unsprung members of said vehicle comprising:
- (a) load sensing means engageable with the other of said sprung and unsprung members for measuring the distance therebetween to provide an empty setting and a load setting of said changeover valve device depending upon said distance being greater or less than a predetermined distance corresponding to the changeover point between said empty and load settings;
(b) an inlet connected to said control valve device and an outlet connected to said brake cylinder device;
(c) supply valve means including a valve member between said inlet and outlet via which fluid under pressure is conducted;
(d) a balance piston to which said valve member is connected having equal opposing pressure areas subject to the fluid pressure effective at said inlet in said load setting of said changeover valve;
(e) an equalizing reservoir;
(f) empty/load valve means operated by said load sensing means for de-pressurizing one of said opposing pressure areas in said empty setting of said changeover valve device to establish a differential pressure across said balance piston in the direction of closure of said valve member, said empty/load valve means in said empty setting further connecting said inlet to said equalizing reservoir; and
(g) regulating valve means for interrupting said fluid pressure communication between said inlet and said equalizing reservoir when the fluid pressure at said inlet is less than a predetermined value.
3 Assignments
0 Petitions
Accused Products
Abstract
An empty/load changeover valve device for a railway car having a proportioning valve including a valve member via which brake cylinder pressure is supplied and released and a balance piston to which the valve member is connected. The balance piston has equal opposing pressure areas both of which are subject to brake pressure in the "load" setting of the changeover valve device, one of the pressure areas being vented in the "empty" setting, thereby establishing either a non-proportioning mode of brake control or a proportioning mode of brake control. In the "empty" setting, brake supply pressure is connected to an equalizing reservoir. A regulating valve is provided to interrupt this connection until the brake supply pressure reaches a predetermined value, thereby preventing the other pressure area of the balance piston from being unloaded sufficiently to cause an inadvertent opening of the check valve member and a consequent drop in brake cylinder pressure.
17 Citations
10 Claims
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1. For use in a railway vehicle brake control system including a brake pipe charged to a certain chosen pressure, a brake cylinder device, a brake control valve device via which fluid under pressure is supplied to said brake cylinder device and released therefrom in accordance with variation of the fluid pressure in said brake pipe, and sprung and unsprung members, an empty/load changeover valve device mounted on one of the sprung and unsprung members of said vehicle comprising:
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(a) load sensing means engageable with the other of said sprung and unsprung members for measuring the distance therebetween to provide an empty setting and a load setting of said changeover valve device depending upon said distance being greater or less than a predetermined distance corresponding to the changeover point between said empty and load settings; (b) an inlet connected to said control valve device and an outlet connected to said brake cylinder device; (c) supply valve means including a valve member between said inlet and outlet via which fluid under pressure is conducted; (d) a balance piston to which said valve member is connected having equal opposing pressure areas subject to the fluid pressure effective at said inlet in said load setting of said changeover valve; (e) an equalizing reservoir; (f) empty/load valve means operated by said load sensing means for de-pressurizing one of said opposing pressure areas in said empty setting of said changeover valve device to establish a differential pressure across said balance piston in the direction of closure of said valve member, said empty/load valve means in said empty setting further connecting said inlet to said equalizing reservoir; and (g) regulating valve means for interrupting said fluid pressure communication between said inlet and said equalizing reservoir when the fluid pressure at said inlet is less than a predetermined value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification