Brake control valve

Claim 2

A brake control valve apparatus comprising: a source of fluid pressure; a brake feed passage; a primary brake apply passage; a secondary brake apply passage in fluid communication with the primary brake apply passage; exhaust passage means; brake apply regulator valve means comprising operator input means for establishing a desired braking level, valve means operatively connected with the operator input means for controlling fluid flow from said source of fluid pressure to said primary brake apply passage at a pressure level determined by said operator input means; flow regulator valve means for selectively connecting said source to said secondary brake apply passage comprising a first pressure responsive area; means for urging said flow regulator valve means to a first position connecting said source to said secondary brake apply passage in response to fluid pressure is said primary brake apply passage, and a second pressure responsive area means in fluid communication with said brake feed passage for urging said flow regulator valve means to a second position disconnecting said source from said secondary brake apply passage in response to pressure in said brake feed passage; and flow restriction means and pressure reduction means disposed in parallel fluid flow relation between said primary brake apply passage and said brake feed passage for controlling both the change in pressure level of the fluid in said brake feed passage and the flow of fluid to said brake feed passage for limiting the pressure rise in said brake feed passage while providing a high flow rate until the pressure level in said brake feed passage operating on said secondary pressure responsive area is sufficient to move said flow regulator valve means to said second position.

Claim 3

A brake control valve apparatus comprising: a source of fluid pressure; a brake feed passage; a primary brake apply passage; a secondary brake apply passage in fluid communication with the primary brake apply passage; exhaust passage means; brake apply regulator valve means comprising operator input means for establishing a desired braking level, valve means operatively connected with the operator input means for controlling fluid flow from said source of fluid pressure to said primary brake apply passage at a pressure level determined by said operator input means; flow regulator valve means for selectively connecting said source to said secondary brake apply passage comprising a first pressure responsive area means for urging said flow regulator valve means to a first position connecting said source to said secondary brake apply passage in response to fluid pressure is said primary brake apply passage, and a second pressure responsive area means in fluid communication with said brake feed passage for urging said flow regulator valve means to a second position disconnecting said source from said secondary brake apply passage in response to pressure in said brake feed passage; and flow restriction means and pressure reduction means disposed in parallel fluid flow relation between said primary brake apply passage and said brake feed passage for establishing a pressure differential between said primary brake apply passage and said brake feed passage when the fluid flow therethrough is above a predetermined rate to limit the pressure acting on said second pressure responsive area to a level insufficient to overcome a force imposed on said flow regulator valve by the pressure acting on said first pressure responsive area means, and said pressure acting on said second pressure responsive area means being sufficient to cause said flow regulator valve to move to said second position to disconnect said source of fluid pressure from said secondary brake apply passage when the flow therethrough is below the predetermined rate.

Claim 4

A brake control valve apparatus comprising: a source of fluid pressure; a brake feed passage; a primary brake apply passage; a secondary brake apply passage in fluid communication with the primary brake apply passage; exhaust passage means; brake apply regulator valve means comprising operator input means for establishing a desired braking level, valve means operatively connected with the operator input means for controlling fluid flow from said source of fluid pressure to said primary brake apply passage at a pressure level determined by said operator input means; flow regulator valve means for selectively connecting said source to said secondary brake apply passage comprising a first pressure responsive area means for urging said flow regulator valve means to a first position connecting said source to said secondary brake apply passage in response to fluid pressure is said primary brake apply passage, and a second pressure responsive area means in fluid communication with said brake feed passage for urging said flow regulator valve means to a second position disconnecting said source from said secondary brake apply passage in response to pressure in said brake feed passage; and flow restriction means and pressure reduction means disposed in parallel fluid flow relation between said primary brake apply passage and said brake feed passage for establishing a pressure differential between said primary brake apply passage and said brake feed passage when the fluid flow therethrough is above a predetermined rate to limit the pressure acting on said second pressure responsive area to a level insufficient to overcome a force imposed on said flow regulator valve by the pressure acting on said first pressure responsive area means, and said pressure acting on said second pressure responsive area means being sufficient to cause said flow regulator valve to move to said second position to disconnect said source of fluid pressure from said secondary brake apply passage when the flow therethrough is below the predetermined rate.