Patent GB-191403727-A (GB)
Title: Improvements in Hydraulic Lifts.
Inventor: MELLERSH-JACKSON WILLIAM JOHN
IPC: B66B9/04
Filed: 1914-02-12
Granted: 1915-02-12
Abstract: 3727. Jackson, W. J. Mellersh-, [Ericson, J.]. Feb. 12. Platform lifts.-Balanced hydraulic lifts for canals, roadways, &c. are provided with a series of groups of lifting-plungers so disposed and interconnected hydraulically as to prevent tilting of the lifts even though the lifts may be unevenly loaded or in the event of leakage in any part of the system. Fig. 1 shows one of the two balance lifts 4 as applied to a canal, of which 1 is the top reach and 2 an intermediate reach situated midway between the top and the bottom reach which is not shown. When the lift 4 is level with the reach 1, the other lift (not shown) is level with the bottom reach, and at the end of the travel of both lifts, they are level with the intermediate reach 2. Each lift is supported by a group of plungers at each corner and by a single plunger or group of plungers at the centre, for example Fig. 4 shows, in plan, groups of corner plungers E E<1>, F F<1>, G G<1>, H H<1> and a central group N. Each corner group of cylinders upon each lift is hydraulically interconnected with each corner group of cylinders upon the opposite lift, so that the pressure in said group is distributed equally upon the corresponding cylinders of each group of the other lift; for example the cylinders 1, 2, 3, 4 of group E are connected respectively with one cylinder in each of the corners of the other lift. All the corner cylinders are at the same time connected to a constantly-operating pressure pump as follows. Each of the interconnecting-pipes 54, Fig. 4, is connected through pipes 55 to a trunk pipe 56 communicating with a pump 57, check valves 58 opening outwardly from the pump being placed in the pipes 55. To reduce the travel of the lifts, the water level in the cylinders may be lowered by the simultaneous operation of valves 62, Fig. 5, situated in branch pipes 59 leading from the branch pipes 55 to a common exhaust pipe 61. The central cylinders have a similar valve 62', Fig. 5, and are similarly connected to the pump 57, Fig. 4, through pipes 66<1>, 67<1>, 68, 56 through a check valve 69. The lifts are operated by lowering the water-level in the lower tank but water may also be positively moved from one central group of cylinders to the other by a pump 74. Fig. 4, the delivery of which is connected through pipes 71, 72 to the main pipes 67', 67 respectively, the intake of the cylinder being also connected to the said pipe through branches 75, 76. Cut-off valves 65, 66, 85, 86 are fitted in these pipes and relief valves 79, 80 opening in opposite directions short-circuit the flow when a certain pressure is reached. Referring to Fig. 6, the upper end of each cylinder abuts against shoulders 19 in a bed-plate 18. The plungers 26 are preferably hollow, and in them are fixed plugs 28 connected to struts 27 and supported by sleeves 31. A valved vent pipe 32 extends through the plug. A cap-plate 34 is fixed upon the tops of the plungers and upon this plate is supported by roller bearings 36, a bearing-plate 30 carrying the lift 4. The lift is locked in any position by braking mechanism 40 consisting of gripping-jaws 41, 42, Fig. 7, extending round the plunger and opened pneumatically through toggle-links 44, 44<1>. The plungers are guided by superimposed guide-bars 47. Fig.1, extending transversely of the lock and seated in guideways 48, Fig. 4; they are connected together and to the cap-plates 34 by chains 50, 51. The central plungers may be connected directly to the lift. The cylinders of very long lifts will be made in sections connected together by sleeves 17, Fig. 1. Wicket gates 6, 8, Fig. 1, are provided to isolate the water in the lift and canal reaches respectively, the spaces between adjacent gates being drained by valved conduits 10. These conduits are also employed to lighten the lower lift by running water therefrom.