Patent GB-1252156-A (GB)
IPC: B60T7/18
Filed: 1968-10-28
Abstract: 1,252,156. Movements of vehicles utilizing; railway vehicle undercarriages. PULLMAN Inc. 28 Oct., 1968 [29 Dec., 1967], No.51049/68. Headings B7J and B7L. [Also in Divisions F2 and G3] In a fluid pressure operated braking system (see Division F2) for controlling the speed of a rail vehicle, a governor 44 is responsive to the speed of the vehicle and the governor and a trip valve 38 co-operate to control the brake applying means so that the brakes are applied when the vehicle speed is above a predetermined maximum value and the trip valve is set. As shown in Figs. 3 and 4 the governor 44 is driven from a wheel axle 8 by way of a belt drive 39 acting through a gearing arrangement 43a-43d. When the speed of the vehicle is less than 4 miles per hour, an automatic speed control device 28 will be in the position shown in Fig. 4 wherein flyweights 52, 52 are in their inner position in which the intermeshing levers 48, 48 are in a horizontal position to drive the axially movable right hand governor sleeve 47 to the right to allow a bleed valve arrangement 54 to remain closed to close the connection between a line 57 and the connection 58, 58a to the brake applying cylinder 23 (Fig. 6). In the position shown in Fig. 4, the trip mechanism 38 consisting of a valve arrangement adapted to be opened by a trip structure 29 located on the track remains closed under the influence of the spring 38c to allow collar 61m to engage a spool shoulder 61h of a supply valve 61 thus closing off connection between a conduit 63 leading to a reservoir isolating valve 62 (Fig. 6) and the conduit 57 leading to the speed control valve 56. As the car runs over the mechanical trip arrangement 29 the valve arrangement 38 is opened to allow a momentary jet of pressurized air to pass from the line 47a to the line 37 and into the port 61k of the supply valve 61 to move the spool 61c to the left to its open position, Fig. 5 (not shown) wherein the flyweights 52 are moved outwardly when the speed exceeds 4 miles an hour to allow the right hand spindle 47 to move to the left thus permitting the bleed valve 54 to be unseated so that pressurized air can escape from the chamber 55b of the speed control valve 56 and allow communication between the conduits 57 and 58 to the brake cylinder 23 thereby applying the brakes shoes 19 against the wheels 9 to slow the railway vehicle 1 down. When the railway vehicle is uncoupled from a train for sorting in a goods yard, a brake release rod 25 (Fig. 6) is applied on each vehicle to activate a release valve to discharge all of the air pressure from both reservoirs and the entire brake system to release the brakes. When the brake release rod 25 is pulled, the reservoir two-way isolating valve 62 is rotated to isolate the emergency reservoir 21a from the conventional air brake system so as to render the emergency air pressure available to the supply valve 61 such that air cannot get back into the regular brake system because of leaking AB valves 22 and cause the brakes to be re-applied. When the vehicle has been uncoupled and prior to the pulling the brake release rod, an actuator 71 is retracted because there is no brake pipe pressure. The speed control means 28 is thus effective to limit the speed of the railway vehicle 1 to about 4 miles an hour and the brakes of the car are applied only if such a speed is exceeded whereupon the governor spindle 47 moves slightly to the right and the bleed valve 54 closes since its stem 54a does not ride on the protuberance 46b of the governor spindle sleeve 47. This causes the spool valve 56h of the speed control valve 56 to shift to the right in the position showing in Fig. 4 and the air pressure in the brake cylinder 23 is exhausted, thus releasing the brakes. Should the railway vehicle again attain a speed in excess of 4 miles an hour the brakes are re-applied and again released as the speed drops to slightly less than 4 miles an hour. When the railway vehicle is stationary, the governor becomes fully extended shutting off the supply valve as shown in Fig. 4 and the device is automatically reset for another triggering action as some future time when the railway vehicle is again sorted.