Patent ID: 9227612
Filing Date: 2016-01-05
CPC Classification: B60T,B64C,F15B

Claim Text:
1. A hydraulic system for an aircraft comprising: a brake operation device; a pressure supply; a reservoir; a brake valve; a shut-off valve in fluid communication with and disposed between the pressure supply and the brake valve, the shut-off valve including a spool, a poppet on the spool, a first piston connected with the spool for movement therewith, a first valve seat, a first spring biasing the first piston and the poppet in a first direction toward the first valve seat, a second piston receiving the first piston, a second spring biasing the second piston in the first direction and a second valve seat each positioned in the shut-off valve, wherein movement of the poppet is controlled by operation of the brake operation device, wherein the poppet is movable between a first position where the poppet acts against the first valve seat and a second position where the poppet acts against the second valve seat, in the first position fluid flow is blocked between the pressure supply and the brake valve through the shut-off valve, in the second position fluid flow is allowed between the pressure supply and the brake valve through the shut-off valve; and a wheel brake in fluid communication with and downstream from the shut-off valve, wherein the wheel brake operates at a maximum fluid pressure and the wheel brake is at x % of the maximum pressure when the poppet is in the second position, where x %<100%; wherein the brake operation device includes a master cylinder and a pedal, wherein the master cylinder is in fluid communication with the shut-off valve; wherein with the poppet in the second position fluid is prevented from flowing between the pressure supply and the master cylinder.