Patent GB-802113-A (GB)
Title: Improvements in and relating to rail grinders
IPC: E01B31/17
Filed: 1956-11-07
Abstract: 802,113. Rail grinders. SPENO RAILROAD BALLAST CLEANING CO., F. Nov. 7, 1956 [Nov. 15, 1955], No. 34071/56. Class 60. A rail grinder comprises a truck movable along the rail R, Fig. 1, to be ground, a set of grinding heads 5 disposed on the truck for vertical movement into and out of engagement with the rail, separate pressureresponsive devices 18 associated with each grinding head for vertically adjusting and partially counterbalancing it, and a source of fluid pressure communicating with the pressureresponsive devices at a regulatable pressure whereby each head is counterbalanced to an extent less than its weight. As shown in Fig. 1, a rail car 1 is fitted with two trucks 2, 2a, each of which carries six grinder heads 5 arranged in two sets of three on each side. Each head comprises a grinding wheel 6, Fig. 2, on the shaft 7 of an electric motor 8 arranged to be moved vertically in a frame 9, 10, 11 by two hydraulic piston-and-cylinder devices 13. Each pair of devices 13 is connected with a reservoir 18, Fig. 5, which is subjected at its upper part to air pressure from a differential-pressure shuttle valve 29. Air at relatively high pressure is supplied from a manifold 43 to the shuttle valves 29 through a valve 33. According to the setting of this valve, air passes through one or other of two manifolds 26, 36 which communicate with the opposite ends of the shuttle valves ; when the valve is set to supply one manifold, the other manifold is connected by the valve to a common exhaust line 41. Each of the connections from the manifold 26 includes in it an adjustable pressure-reducing valve 21. In normal operation, the valve 33 is set for supply through the manifold 26 so that relatively low pressure air as determined by the valves 21 passes through the shuttle valves and acts on the reservoir 18 to cause the devices 13 to partially counterbalance the weight of the grinding heads. When it is desired to raise the gang of grinders out of engagement with the rail (as, for example, to clear a crossing or obstruction), the control valve 33 is reversed to divert the air supply to the manifold 36 and so set the shuttle valves for the supply of air at high pressure to the reservoirs 18. The sets of grinding heads employ a common air supply manifold 43 and a common exhaust line 41. To ensure that grooves are not cut into the rails when the car nearly stops, a speed-responsive master control valve 46 is connected between the supply manifold 43 and the exhaust line 41. When the speed drops to a pre-determined value, a governor-controlled switch 49, Fig. 1, which is driven by a chain 50 from the adjacent axle of the truck 2, operates the solenoid 48, Fig. 5, of the valve 46 to cause air at the higher pressure to be supplied through the line 41 and control valve 33 to raise the pressure in the reservoirs 18 sufficiently to lift the heads. Each of the adjustable pressure-reducing valves 21 is mounted on a console 23 which is also fitted with pressure gauges indicative of the pressure on the outlet side of each such valve and ammeters arranged in series with the respective drive motors 8 of the heads 5.