Patent GB-284229-A (GB)
Title: Improvement in brake mechanism for automotive vehicles
IPC: B60T13/24
Filed: 1927-11-24
Abstract: 284,229. Bragg, C. S., and Kliesrath, V. W. Jan. 25, 1927, [Convention date]. Fluid-pressure.-Brake operated mechanism comprises main and auxiliary actuators respectively connected to the brakes on a tractor and a trailer vehicle and operated by exhausting the chambers on the one side uf the pistons, main valve mechanism whereby both actuators may be simultaneously operated and an auxiliary valve which permits of the independent operation of either actuator. The apparatus shown in Fig. 2 includes main and auxiliary single-acting actuators P, P' mounted respectively on the tractor and trailer vehicles. The actuator P is of the kind described in Specification 250,195 and comprises valves 40, 41 disposed in the hub of the piston 3 and slidably mounted upon the tubular rod 20 which is connected to the induction pipe of the tractor engine by the pipe 62. A non-return valve 62b and a restricting valve are arranged in the pipe 62. The valves 40, 41 are pressed apart by a cushioning device 50 and are operated by projections on the rod 20. The brakes of the traction vehicle are connected to the piston rod 5. A tubular rod 5<a> also secured to the piston is open to the atmosphere at its outer end. A spring 46 acting between the rods 5, 20 normally unseats the valve 40 so that the piston chamber is open to atmosphere by way of the piston rod 5a and the port 34. Upon moving the valve rod 20 towards the left hand by depressing the operating pedal, the valves 40, 41 are seated and unseated respectively and the piston chamber is thus opened to the suction pipe through apertures 21 in the rod 20 and the port 34, thereby applying the brakes. If the pedal is held in an intermediate position the suction valve becomes seated by the movement of the piston. The brakes may be gradually released by permitting the pedal to return so that the valve 40 is opened by the spring 46. A head 26 on the rod 20 is arranged to engage a shoulder on the piston rod 5 after sufficient lost motion to allow of the opening of the valve 41 so that the direct effort of the operator may be applied to the piston and the tractor brakes. A pipe 90 extends between the piston chambers of the trailer and tractor acuators P, P' and a valve 94 disposed in this pipe is normally in the position shown so that these chambers are connected and the trailer brakes are thus operated simultaneously with the tractor brakes. The valve can be moved into a position, Fig. 5; in which the chamber of the actuator P<1> is cut off from that of the actuator P and is connected to a pipe 92 connected to the suction pipe 62 so as to effect the independent application of the trailer brakes. The valve 94 may also be turned to an intermediate position in which it closes hoth the pipes 90 and 92 so that the tractor brakes only are operated by the valves 40, 41. The valve 94 is actuated by a cable 98 connected to a hand lever disposed adjacent the driver's seat. The valve 94 is arranged in that part of the pipe 90 which is carried by the tractor so that it may be used to close this pipe and the pipe 92 when it is desired to run the tractor detached from the trailer. Fig. 8 shows alternative apparatus in which double-acting actuators P<2>, P<3> are provided. The actuator P<2> comprises a chamber 217 connected to the suction pipe 262 by the valve rod 220 and ports 221 and a chamber 218 connected to the atmosphere by ports 224 the valve rod and the passage 229. The valve rod 220 actuates suction valves 241, 242 and air inlet valves 240, 243 adapted to connect the two piston chambers to the chambers 217, 218 by way of ports 234, 235 and passage 219. Normally the valve rod 220 abuts against a stop 223 and the valves 240, 243 are unseated so that the two piston chambers are open to atmosphere. Pipes 290, 291 extend between the respective piston chambrs of the actuators and a valve 294 is normally in the position shown to connect the two parts of the pipe 290 so that both actuators are simultaneously operated by the valves 240 - - 243. The valve 294 can be actuated in a similar manner to the valve 94, Fig. 2 to operate the actuator P<3> alone by connecting the suction pipe 292 thereto or to permit of the actuation of the actuator P<2> alone. The pipe 291 may be closed by a valve 291<a> when the trailer is uncoupled.