Patent GB-276452-A (GB)
Title: Improvements in or relating to fluid pressure brake apparatus for vehicles
IPC: B60T13/40
Filed: 1926-06-07
Abstract: 276,452. Peters & Co., Ltd., G. D., Porter, A. S., and Palmer, B. W. June 7, 1926. Fluid-pressure.-In a fluid pressure brake for a tractor and trailer the driver's valve is constructed to apply the brakes on the trailer in one of its operative positions and the brakes on both vehicles in another of its operative positions and in the latter case the brake application on the trailer commences before that on the tractor. Also, the brake release on the tractor commences before that on the trailer. Quick release valves for accelerating the release of the brakes and emergency valves for applying the brakes in the event of a break-away are provided. The body portion 15, Fig. 2, of the driver's valve is provided with ports 27 - - 29 leading to the valve seat and connected to the tractor brakes, trailer brakes and the atmosphere respectively, and the valve 17 is provided with a cavity 24 adapted to connect these three ports and thus exhaust the brakes, when the handle 19 is in the running position at the end of the notched segment with which it engages by means of a spring plunger. When the handle is moved to the first notch the cavity 24 still connects the tractor brakes to exhaust, but a port through the valve 17 connects the port 28 and the tractor brakes to the passage 21 connected to the main reservoir and applies the brakes. Movement to the next notch closes all ports and holds the trailer brake in lap position. Further movement of the driver's valve connects both the tractor brakes and the tractor brakes by means of ports through the valve 17 to the main reservoir. On reverse movement of the driver's valve the movement of the cavity 24 over the ports will release the tractor brakes before the trailer brakes. The valve 17 is held against its seat by main reservoir pressure and a spring 22 in a plunger 23. The valve spindle 19 is provided with a projecting toe 18a or an irregularly shaped end portion adapted to enter a corresponding recess in the valve 17. The hole in the boss of the handle and the end of the spindle 18 on which it fits are so shaped as to ensure the handle being assembled in correct position. The quick release valve 30 and the emergency valve 44 are shown combined in Fig. 11 and may be fitted on both the tractor and trailer. The brake cylinders are connected to ports 35 and are supplied through a port 62 and a ball valve 41 with fluid under pressure which depresses the diaphragm 33 closing the exhaust valve 37. When the pressure above the diaphragm is reduced when the driver's valve is moved to release position, the pressure in the brake cylinders raises the diaphragm 33 and opens the valve 37 to exhaust the cylinders. In normal operation of the brakes the cylinders are supplied from the driver's valve through a port 55 in the emergency valve, past a valve 52 and by port 62. An auxiliary reservoir connected to port 45a is charged from the main reservoir through a port 48, and a ball valve 56 in a diaphragm 49. On the separation of the pipe from the main reservoir on breaking away of the vehicles, the pressure fluid above the diaphragm 49 is released, the diaphragm 49 rises under auxiliary reservoir pressure and raises valves 51, 52 connected to it. The valve 51 opens communication between the auxiliary reservoir connected to the port 45<a> and the brake cylinder port 62, thus applying the brakes, and the valve 52 cuts off the brake cylinder from the main reservoir port 55 which is open to atmosphere due to the breaking of the connecting pipe. In the event of a break-away, to maintain pressure in the main reservoir pipe in the tractor which normally feeds the auxiliary reservoir a valve is provided comprising a spring-loaded valve 58 carried by a diaphragm 59, the load of the spring being such that full main reservoir pressure acting on the diaphragm forces it up and holds the valve off its seat, but on the pipe 42 being opened at the coupling and the pressure dropping below the value of the spring pressure the valve closes.