Patent GB-816862-A (GB)
Title: Improvements relating to railway track ballast tamping apparatus
IPC: E01B27/17
Filed: 1955-12-21
Abstract: 816,862. Railway tamping machines. HURSH, S. R., and McWILLIAMS, J. B. Dec. 21, 1955, No. 36686/55. Class 104 (2). A railway ballast tamping machine movable along the rail track and provided with at least one support to which a plurality of tampers are connected has the support guided for vertical movement and the tampers comprise pneumatically-actuated percussion tampers individually connected by connecting-means, embodying spring cushioning, to the support so that when the tampers are lowered to the operative position they will yield individually in the event of abnormal resistance of the ballast to being compacted beneath the sleepers. The track is first raised at one end to the new level by hand jacks J and the vehicle is then run into position so that the rear wheels 4 rest on the hump formed by the raised track, in which position the vehicle is held by a band-brake associated with the axle of the rear wheels 4 and actuated on the operation of either of the hand valves 40, 41, Figs. 4, 30. The brake can, for safety purposes, be actuated by a hand lever 28, Fig. 16 (not shown). A valve 64, Fig. 30, is now actuated to admit compressed air into a cylinder 55 of a rail gripping device 51 to pivot track gripping hooks 52 into engagement with the underside of the rail heads R (Fig. 18). One of the sets of valves 108, 113, Figs. 1 and 3, arranged overhead, in each corner of the rear end of the vehicle, are operated to admit compressed air to the tops of hydraulic lift cylinders 89a, 90a to press a foot 82 of the jack 81 on to the track bed between a pair of sleepers T. The cylinders 89a, 90a can adjust the foot 82 to suit any transverse tilt that may be required to be given to the track, such tilt being measured on gauges 122, 123, Fig. 4, provided on the vehicle. A valve 63, Fig. 3, at the front end of the vehicle, is operated to effect operation of a rail gripping means 50, similar to that previously described, at the front end of the vehicle, and either of a pair of valves 98, 103, arranged overhead in each forward corner of the vehicle, is actuated to operate a lifting jack 80, similar to jack 81, at the front end of the vehicle. The extent to which the track is raised by the jack 80 is determined by a telescope 120, fixed to the vehicle, sighting on a pre-set level-rod P, Fig. 1. A similar telescope 121, Fig. 3, is also provided at the rear of the vehicle. The tamping carriages 150, 151 can now be moved on wheels 153, 154 along vehicle side-frames 2 by air motors 157, Fig. 4, driving axles 155 through reduction gears 156 on operation of a valve 211, Figs. 6 and 7. The air supply to each tamping carriage is through articulated pipes 205, 206, Fig. 4. A cord 196, Fig. 6, is pulled to release spring- loaded dogs 190 engaging a bridge-piece 192 connected to a cross-head 162 from which the tampers 167 are suspended. A handle of a valve 212 associated with one or the other of tamping carriages 150 or 151 is moved in one direction to allow compressed air to enter the upper end of a cylinder 164 to lower, for a time, together upper and lower crossheads 162, 161. On reaching the position shown in Fig. 12 the downward movement of the crosshead 161 is stopped by stops 183 attached to rods 182 suspended from vehicle frame members 159. The stops 183 engage collars 184 attached to tubes 160 connected to the lower crosshead 161, the crosshead 162 however continues its downward movement, Fig. 13, so that the tamping tools are pivoted inwardly towards the rail support by studs 176 engaging arcuate slots 177 in wire members 178 attached to the lower crosshead 161. Repeated raising and lowering of the tamping tools 167 will compact the ballast beneath the sleeper T. Springs 174 acting between the telescopic components of the links 170 yield if excessive resistance is encountered to prevent tamper bar breakages. After compacting the ballast the handle of the valve 212 is moved in the opposite direction to raise initially the crosshead 162 until the tampers 167 are vertical in which position the crosshead 161 is moved upwards. The tamper carriages 150,151 are now moved to positions above other sleepers and the operation is repeated. Each pneumatic percussion type tamping tool 167 is actuated by compressed air supplied through a flexible hose 227, Fig. 7, fed from a manifold 225 from a main 219, a relay valve 229 and pipes 220, 221, 223 and 224, Fig. 28. A disc 233, Fig. 29, in the relay valve 229 is moved to the left by compressed air fed from the upper end of the cylinder 164 through a pipe 239, during the tamping operation, to close a port 236 and to open a port 235 to allow compressed air to operate the tools 167. When the tamping operation is finished and the valve 212 is moved to supply compressed air to the lower end of the cylinder 164 to raise the tools 167 the compressed air supply to the upper end of the cylinder 164 and hence pipe 239 is cut off and the port 235 closed to stop the supply of compressed air to the tampers 167. In a modification, not shown, for tamping only, two groups of tamping tools are arranged one group above each rail and independently operable and mounted overhanging the front end of the vehicle.