Patent GB-1169865-A (GB)
Title: Air Braking System
Inventor: MCKNIGHT JAMES
IPC: B60T13/40
Filed: 1968-07-16
Abstract: 1,169,865. Vehicle air brake systems. FORD MOTOR CO. Ltd. 16 July, 1968, No. 33760/68. Headings F2E and F2F. The system comprises:- (a) First and second service reservoirs 20, 21 respectively, and a control reservoir 14 in which air pressure is maintained by a compressor 13. (b) A first relay valve 26 for supplying air from the first reservoir 20 to a first brake actuator line connected to a first set of actuators. (c) A second relay valve 27 for supplying air from the second reservoir 21 to a second brake actuator line connected to a second set of brake actuators. (d) A service control valve 23 operatively connected to a brake pedal 25 and supplying air, when the pedal is depressed, from the control reservoir 14 to the first and second relay valves 26, 27 to open them for applying the brakes. Preferably the first and second sets of actuators actuate brakes on different axles of the vehicle. Each brake actuator includes separate service and auxiliary chambers to apply the brake when air is supplied to either or both chambers. An auxiliary reservoir 22 may also be provided, and is maintained at pressure by the compressor 13; an auxiliary control valve 24 is connected to the brake pedal 25 and is opened by further depression of the brake pedal beyond that necessary to open the service control valve; this valve establishes communication between the auxiliary reservoir 22 and the auxiliary air chambers of at least some of the brake actuators as shown, the brake actuators 12 of the front wheels 10, via a double check valve 30. All the brake actuators 12 include lock actuators with locking means normally held disengaged by air supplied under pressure from a parking reservoir 18 via a parking brake control valve 31. This valve is also connected to the auxiliary chambers of all the brake actuators to supply air from the parking reservoir thereto for applying the brakes prior to engagement of the locking means for parking; the same operation is performed to relieve the brake pressure before air is admitted to the lock actuators for disengagement of the locking means. It is the double check valve 30 (which is connected to the parking brake control valve 31) which permits the auxiliary chambers of the brake actuators 12 of the front wheels 10 to be pressurized by either the auxiliary reservoir 22 or the parking reservoir 18, as previously described. The auxiliary control valve 24 also supplies air to a trailer auxiliary supply line 36 for connection at 37 to the auxiliary braking system of a trailer. The second relay valve 27 also supplies air to a trailer service supply line 34 for connection at 35 to the trailer service braking system. From the second service reservoir 21 a line 38 is provided for connecting at 39 to the trailer emergency braking system; the line includes a pressure release valve 40. Pressure gauges 41 and a low-pressurewarning buzzer 42 are provided. A warning light 43 indicates when the locking means of the lock actuators are engaged. In the vehicle system a leak or failure in the air lines serving one axle does not affect application of the brakes to the other axle. As shown, the connection between the second service reservoir 21 and the rear wheels 11 via the second relay valve 27 includes a loadapportioning valve 28, mechanically connected to the rear suspension and controlling the relative braking pressures applied to the front and rear wheels.