Control valve arrangement for combined brake cylinder and air reservoir device

Fluid pressure brake apparatus for a railway vehicle operative in response to variation of fluid under pressure in a brake pipe of said vehicle comprising:

• (a) a brake cylinder device having:
• (i) a power cylinder portion;
• (ii) a power piston operatively disposed in said power cylinder portion and cooperating therewith to form an application chamber on one side of said power piston and a release chamber on the opposite side thereof;
• (iii) a positioning cylinder portion;
• (iv) a positioning piston operatively disposed in said positioning cylinder portion for engagement with said power piston, said positioning piston cooperating with said positioning cylinder portion to form on one side thereof a positioning chamber;
• (v) biasing means for urging said power piston toward a brake release position;
• and
• (b) a control valve device including:
• (i) an exhaust passage;
• (ii) charging valve means having a charging position in which said positioning chamber is vented and said application and release chambers are in fluid pressure communication with said brake pipe, whereby said bias means is effective to move said power piston to said brake release position and having a cut-off position in which said venting of said positioning chamber and said charging of said application and release chambers is interrupted;
• (iii) service valve means operable to an application position in response to a reduction of said brake pipe fluid under pressure for operating said charging valve means to said cut-off position and for conducting flow of fluid under pressure from said release chamber to said position chamber, said positioning piston and accordingly said power piston being movable from said brake release position to a brake application position when the fluid pressure in said positioning chamber reaches a predetermined value;
• and
• (iv) transfer valve means operatively responsive to said positioning chamber fluid under pressure relative to said release chamber fluid pressure for establishing fluid pressure communication between said release chamber and said exhaust passage to thereby establish a pressure differential between said application and release chambers to cause said power piston to provide a braking force.

Fluid pressure brake apparatus for a railway vehicle operative in response to variation of fluid pressure in a brake pipe of said vehicle 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 under pressure is normally stored and a return spring urging said piston toward a brake release position, said piston being operative in response to the exhaust of fluid under pressure from said release chamber to provide a braking force in accordance with the pressure differential between said application and release chambers;
• (b) control valve means operative in response to a reduction of said brake pipe fluid pressure for connecting said fluid under pressure from said release chamber to an exhaust passage;
• (c) check valve means for venting said exhaust passage of said fluid under pressure from said release chamber when the pressure therein exceeds a predetermined amount;
• and
• (d) changeover valve means having first and second positions for connecting said exhaust passage to atmosphere directly when said vehicle is in a load condition and connecting said exhaust passage to atmosphere via said check valve means when said vehicle is in an empty condition.

Fluid pressure brake apparatus for a railway vehicle operative in response to variation of fluid under pressure in a brake pipe of said vehicle comprising:

• (a) a brake cylinder device having:
• (i) a power cylinder portion;
• (ii) a power piston operatively disposed in said power cylinder portion and cooperating therewith to form an application chamber on one side of said power piston and a release chamber on the opposite side thereof;
• (iii) a positioning cylinder portion;
• (iv) a positioning piston operatively disposed in said positioning cylinder portion for engagement with said power piston, said positioning piston cooperating with said positioning cylinder portion to form on one side thereof a positioning chamber;
• (v) biasing means for urging said power piston toward a brake release position;
• and
• (b) a control valve device including:
• (i) charging valve means having a charging position in which said positioning chamber is vented and said application and release chambers are in fluid pressure communication with said brake pipe, and said bias means being effective to move said power piston to said brake release position and having a cut-off position in which said venting of said positioning chamber and said charging of said application and release chambers is interrupted;
• (ii) service valve means operable to an application position in response to a reduction of said brake pipe fluid pressure for operating said charging valve means to said cut-off position and for conducting flow of fluid under pressure from said release chamber to said positioning chamber, said positioning piston and accordingly said power piston being movable from said brake release position to a brake application position when the fluid pressure in said positioning chamber reaches a predetermined value;
• and
• (c) biasing means for providing a force on said service valve means in a direction opposite to movement thereof to said application position, such biasing being variable prior to said actuation of said transfer valve means and constant thereafter.

In a railway vehicle brake cylinder device controlled in accordance with variation of fluid under pressure carried in a brake pipe of the vehicle and having a brake piston, said brake piston including a positioning area, an application area and a release area, said positioning and application areas opposing said release area, wherein braking force is produced in accordance with a reduction of the fluid pressure acting on said release area relative to the fluid pressure acting on said application area, the method of applying said vehicle brake comprising the steps of:

• (a) imposing a fluid pressure generally equal to the pressure of said brake pipe upon said application and release areas;
• (b) upon a reduction of said brake pipe fluid pressure, connecting the fluid under pressure imposed upon said release area to the fluid pressure imposed upon said positioning area to effect movement of said piston from a release position to an application position;
• (c) sensing the pressure imposed upon said positioning area relative to the pressure imposed upon said release area to indicate said movement of said piston to said application position, and
• (d) transferring said connection of said fluid pressure imposed upon said release area from said positioning area to atmosphere when said pressure acting imposed upon said positioning area reaches a predetermined relationship to the pressure imposed upon said release area.

In a railway vehicle brake cylinder device controlled in accordance with variation of fluid under pressure carried in a brake pipe of the vehicle and having a brake piston, said brake piston including a positioning area, an application area and a release area, said positioning and application areas opposing said release area, wherein braking force is produced in accordance with a reduction of the fluid pressure acting on said release area relative to the fluid pressure acting on said application area, the method of applying said vehicle brake comprising the steps of:

• (a) imposing a fluid pressure generally equal to the pressure of said brake pipe upon said application and release areas;
• (b) upon a reduction of said brake pipe fluid pressure, connecting the fluid under pressure imposed upon said release area to the fluid pressure imposed upon said positioning area to effect movement of said piston from a release position to an application position;
• (c) sensing the pressure imposed upon said positioning area relative to the pressure imposed upon said release area to indicate said movement of said piston to said application position, and
• (d) transferring said connection of said fluid pressure imposed upon said release area from said positioning area to atmosphere when said pressure acting imposed upon said positioning area reaches a predetermined relationship to the pressure imposed upon said release area.