Patent GB-584058-A (GB)
Title: Variable speed rail car mover
IPC: B61J3/00
Filed: 1944-12-12
Abstract: 584,058. Rail-car movers. PIERCE, H. C. Dec. 12, 1944, No. 24926. [Class 103 (ii)] [Also in Group XXIX] A rail-car mover comprises a carriage 10 slidable on a rail 11, Fig. 1, and having a spring- pressed toe 23 which wedges itself between the rail and wheel and a lever 29 mounted on links 30 and oscillated about a movable fulcrum 39 by a piston rod 52 of a fluid pressure engine to lever the wheel by a pivoted pad 34 engaging the wheel rim. The movable fulcrum forms part of the piston of a hydraulic cylinder and is gradually drawn back to increase the travel of the free end of the lever when the rail wheel has started to move. The carriage is transportable on road wheels 106, shown in the transportable position in Fig. 1 but which are retracted when the carriage is in use by means' of a lever 109. The links 30 are pivoted to the lever 29 at 31 and to the sidemembers 21 of the carriage 10 at 32, and the piston rod 52 is connected to the end of the lever 29 by links 53. The base of the carriage 10 and the pivoted pad 34 are faced with friction material. The carriage 10 is pulled along the track by the rotation of the wheel 12 by a connection comprising a wheel 93 engaging the inside of the rim .and removably fastened to a tie bar 92 and a similar wheeled connection bears on the outside of the rim, the tie bar being connected to a pair of leaf springs 89 pivoted at 91 to the carriage and at 105 to a link which adjusts the spring pressure by a hand lever 101. The movable fulcrum 39 bears on a flat surface 29<1>, Fig. 5, on the lever 29 and is fixed to a piston rod 44 working in a fluid pressure cylinder 46 against the tension of springs 48, a pipe 85a being connected through a valve 86 to.pressure or exhaust. The fulcrum 39 at starting is forced out against stops 42 and as the lever 29 starts moving the wheel the valve 86 is opened to exhaust and the fulcrum is retracted by the springs 48. The lever 29 is oscillated by a fluid pressure engine comprising the piston rod 52 connected to a piston 50, Fig. 2, and having a tail rod 58<1> acting as a pilot valve govering the admission of pressure and exhaust through ports 66, 67 to the top end of a shuttle valve comprising a piston 72 and slide valve 59, the bottom of the slide valve being subject to fluid pressure which is overcome when pressure is admitted to the top of piston 72 owing to the difference in areas. A pump 16 mounted on a reservoir 57 and driven by a motor 17 supplies pressure fluid through pipes 58, the exhaust fluid returning to the reservoir through pipes 73. When the piston 50 reaches the bottom of its stroke the shuttle valve is forced upwards due to the space-above the piston 72 of the shuttle valve being placed to exhaust through port 62, passage 68 in the pilot valve, port 67 and exhaust pipe 73. An annular ring 68' in the pilot valve admits pressure from pipe 58, port 66, and pipe 66' to the bottom of the shuttle valve 59 and also through the leak off 83 at the bottom of the valve to force the valve to the top of its stroke. In this position of the valve the space above the piston 50 is placed to exhaust through ports 69, 76, 77, and the space under the piston is open to fluid pressure through pipe 58 and ports 80 and 70. When the piston reaches the top of its stroke the port 66 registers with the port in the tail rod to admit pressure to the top of the shuttle valve which is driven downwards thus putting the top of the piston 50 to pressure through port 75, annular ring 74 in the shuttle, and port 69, the underside of the piston being exhausted through ports 70, 76.