| 摘要 |
A two-circuit brake system, operable either pneumatically or hydraulically, for motor vehicles including an operator-controlled brake valve for effecting supply of brake-operating pressure via a vehicle load-responsive device for regulating brake-operating pressure to the rear axle according to vehicle load, and a relay valve responsive to such regulated pressure for effecting supply of brake-operating pressure to the front axle according to a predetermined ratio. The relay valve includes certain pressure area members which may be replaced by others for varying the rear axle to front axle braking-pressure ratio to suit the particular vehicle on which it is used, and the operator-controlled brake valve is operable for maintaining effectiveness of at least one of the brake circuits, either front or rear, in the event of failure of the other. |
