Patent ID: 6375277
Filing Date: 2002-04-23
Classification: B60T

Abstract:
A release valve apparatus for manually releasing pressure from a brake cylinder of a railcar, said railcar also having at least one reservoir and an electropneumatic valve used in controlling the pressure developed within said brake cylinder, said release valve apparatus comprising:(a) an enclosure defining a control valve housing in which a control valve assembly is disposed and a spool valve housing in which a spool valve assembly is disposed, said enclosure also defining (i) at least one supply channel for connecting said reservoir with said control valve housing, (ii) a brake cylinder passage for connecting said brake cylinder with said spool valve housing, (iii) an exhaust passage communicating said spool valve housing to atmosphere, (iv) a brake control passage for connecting said electropneumatic valve with said spool valve housing, (v) a control chamber communicating with one end of said spool valve housing, (vi) a chamber passage further linking said control chamber with said spool valve housing, and (vii) a release passage interconnecting said control and said spool valve housings; (b) said spool valve assembly comprising a reset spring and a spool member the position of which in said spool valve housing dictates communication between said passages, said reset spring biasing said spool member to a deactivated position wherein (I) said brake control and said brake cylinder passages communicate thereby permitting pressure in said brake cylinder to be controlled via said brake control passage and (II) said chamber and said release passages communicate thereby permitting only said control valve assembly to control pressure in said control chamber; said spool member responsive to build up of pressure in said control chamber by moving (I) away from said deactivated position to switch said brake control passage from communication with said brake cylinder passage to communication with said chamber passage thereby enabling pressure to be built in said control chamber via both said brake control passage and said release passage and (II) then to a released position wherein said release passage is cutoff from said chamber passage thereby enabling pressure in said control chamber to be controlled only through said brake control passage and wherein said brake cylinder passage is connected to said exhaust passage thereby enabling said brake cylinder to vent to atmosphere; said spool member being locked in said released position until pressure in said control chamber is vented via said brake control passage upon occurrence of which said reset spring resets said spool member to said deactivated position; and (c) said control valve assembly having a release lever, a lifter assembly and a lifter spring; said lifter spring biasing said lifter assembly into a closed position wherein said supply channel is cut-off from said control valve housing; said release lever when operated forces said lifter assembly into an open position wherein said supply channel communicates with said control valve housing thereby allowing air from said reservoir to flow past said control valve assembly to atmosphere and to said spool valve housing through said release passage.