Emergency portion for brake control valve

For use in a brake apparatus including a brake pipe, an auxiliary reservoir and an emergency reservoir each normally charged to a certain chosen pressure, a brake cylinder and a fluid-pressure-operated service valve device, a fluid-pressure-operated emergency valve device operative in conjunction with said service valve device in response to a reduction of the pressure in the brake pipe at an emergency rate to effect the supply of fluid under pressure from said reservoirs to said brake cylinder to cause an emergency brake application and comprising:

• a. a casing having therein a plurality of chambers, bores and passageways, one of said bores and one of said passageways cooperating to provide a communication through which fluid under pressure may be released from another chamber other than said plurality of chambers to atmosphere via one of said plurality of chambers, said one bore having at one end an annular valve seat, and one end of said passageways opening into said chambers and bores and the other end being connected respectively to the brake pipe, the emergency reservoir and said another chamber,
• b. a plurality of poppet-type valves for controlling flow between said chambers and passageways, a first one of said poppet-type valves cooperating with said annular valve seat to control flow between said another chamber and said one of said plurality of chambers,
• c. movable abutment means subject respectively to pressure in the brake pipe and in said another chamber, the deflection of said abutment means in one direction responsive to a reduction of the pressure in the brake pipe being effective to cause said abutment means to operate said first one of said plurality of poppet-type valves to release fluid under pressure from said another chamber to atmosphere and a second one of said poppet-type valves to effect the supply of fluid under pressure from the emergency reservoir to the brake cylinder, and the deflection of said abutment means in an opposite direction responsive to a subsequent increase of the pressure in the brake pipe being effective to cause said abutment means to operate a third one of said poppet-type valves to effect the supply of fluid under pressure from the brake cylinder to the brake pipe,
• d. resilient means effective to yieldingly resist deflection of said abutment means in said opposite direction, said resilient means being effective to subsequently deflect said abutment means in said one direction responsive to the pressure in said another chamber increasing to that in the brake pipe,
• e. a first means enabling said first one of said plurality of poppet-type valves to release fluid under pressure from said another chamber to atmosphere at a chosen rate in response to the release of fluid under pressure from the brake pipe at said chosen rate,
• f. a first fluid-pressure-operated means for rendering said first enabling means ineffective to release fluid under pressure from said another chamber at said chosen rate,
• g. a second means enabling a fourth one of said plurality of poppet-type valves to effect the supply of fluid under pressure from said another chamber to said first fluid-pressure-operated means in response to the release of fluid under pressure from the brake pipe at a rate in excess of said chosen rate, and
• h. a third means enabling the release of fluid under pressure from said first fluid-pressure-operated means to atmosphere at a rate different than said chosen rate.