US 4,498,712 AGranted

Empty/load brake control arrangement

AssigneeAmerican Standard Inc.

InventorJames E. Hart

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Abstract

Brake apparatus for a railway vehicle including a brake cylinder device of the type having a pair of interconnected pistons of unequal size to which the vehicle brake rigging is connected. The larger power piston forms an application chamber and a release chamber on its opposite sides in which air is stored for use in controlling the vehicle brakes. The release chamber air is vented to atmosphere during a brake application by way of an empty/load brake control valve device including a changeover valve and a pressure sensitive check valve. When the vehicle is empty, the release chamber air is vented by way of the check valve, which limits the maximum reduction of release chamber pressure and accordingly establishes the maximum empty vehicle brake force obtained. A load piston biases the check valve with application chamber air, which is charged from the brake pipe so that the check valve bias and consequently the maximum reduction of release chamber pressure reflects the train charge. The empty/load control is protected against false transitions of the change-over valve due to car jounce and rock by a delay choke and an exhaust shut-off valve in parallel with the foregoing check valve and changeover valve.

Claims11

Dependent claims

Fluid pressure brake apparatus for a railway vehicle operative in response to variation of fluid pressure in a brake pipe of said vehicle normally charged to a certain chosen value comprising:

(a) a brake cylinder device including at least one piston forming an application chamber and a release chamber on opposite sides thereof in which fluid pressure is normally stored at a value corresponding to said certain chosen value;
(b) control valve means including an exhaust passage operative in response to a reduction of said brake pipe fluid pressure for connecting fluid under pressure from said release chamber to atmosphere via said exhaust passage, said at least one piston being operative in response to said exhaust of fluid under pressure from said release chamber to provide a brake application force in accordance with the pressure differential between said application and release chambers;
(c) changeover valve means for sensing an "empty" condition of vehicle loading so as to interrupt said connection of fluid under pressure from said release chamber to atmosphere;
and
(d) check valve means for connecting said exhaust passage to atmosphere in bypass of said changeover valve means so long as the pressure in said exhaust passage exceeds a predetermined value, said predetermined value being different for different values of said normally chosen brake pipe fluid pressure.

2 more elements

Dependencies are inferred from the claim text.