A New Hydraulic Garage Jack
Page 59
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-1VIEW and extensive works, occupying 15,000 sq. ft., have recently, been acquired by Henry Miller and Co., the well-known maker of hydraulic jacks, etc., at Standard Road, Park Royal, London, N.W.10. Manufacturing, assembling and testing arrangements are being organized on more efficient lines than • was possible in the limited accommodation available at the old addrees in West London, and production has, therefore, been improved. The company has recently introduced, in two models, of 21 tons and 5 tons capacity, an hydraulic high-lift manceuvring jack, suitable for garage purposes. Both small and large models have a closed height of 6 ins, and a maximum, lift of 2 ft. 6 ins. The 21-ton jack -sells at £15 10s., whilst the 5-tonner is listed at 118 15s.
Accompanying illustrations explain the general layout of the new appliance. It is easier to operate than either screw or ratchet types of rnanceuvring jack, being free from the effects of heavy frictional loads. Advantage of the hydraulic Principle is taken to give quick action up to the point where the load is met, and slower action, with correspondingly increased leverage, when the load is being raised.
This useful feature is obtained by employing two pumping pistons of different diameters. When there is no
resistance to the rising of the lifting arm, both pistons take effect, but immediately the load is encountered the larger piston is automatically by-passed, the smaller one providing a powerful leverage. A control valve for lifting and releasing is fitted to the handle, convenient for use whether the handle be raised or lowered, and safety devices ' are incorporated which prevent overloading and overlifting.
The length of the larger model is 7 ft. and the overall width 2 ft., the smaller model measuring a few inches less in all dimensions.
A particularly speedy method of assembling the company's big single-ram commercial-vehicle lifts, which have a capacity of up to nine tons, has been adopted at,the new works. The inner member is bolted to a roof-supporting pillar and the outer member is rested in adjustable crutches on a trolley, which is then wheeled 'up to the inner member. The assembly is carried away on the trolley and lowered into a well, it being necessary to subject these massive components to severe tests. In each case the overall height of the jack when extended to the position of maximum lift is 3 ft. 6 ins.