From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Difficulties of jacking cars and evaluating two permanently fitted four-wheel jacking systems.
| Identifier | ExFiles\Box 179\2\ img168 | |
| Date | 21th January 1932 | |
| ORIGINAL X3117. S. From HS{Lord Ernest Hives - Chair}/Lid.{A. J. Lidsey} c. to Sg.{Arthur F. Sidgreaves - MD} Nor. c. to S. Da.{Bernard Day - Chassis Design} c. to Ry. FOUR WHEEL JACKING. The problem of jacking a car up with the present method of using one mechanical (or hydraulic) jack placed by hand under the front or rear axle has now become very difficult and in many cases almost impossible due to the present trend towards semi-elliptic springs and the complete cowling in of the front and rear of the car. In cases where the body is carried right back to cover the rear spring shackles and a spare wheel is carried on a dummy hub at the rear of the body it is only possible to place a jack securely in position by lying down on the ground. The jacking difficulty has become very pronounced both from our own experience and from the fact that we receive numerous enquiries from customers regarding easier methods of jacking. We must also remember that apart from punctures a car in customers hands is jacked up almost daily for washing purposes. Such as we dislike the idea of adding unsprung weight to the axles in the form of permanently fitted jacks we are forced to admit that there is no other real solution of the problem. At the request of Sales we have obtained and fitted to two of our cars one set of each of the only two systems at present on the market which appear to be at all a reasonable proposition viz., the Jackall Hydraulic System and the D.W.S. Mechanical four wheel jacking system, our impressions of which we give herewith. (1) Jackall Four Wheel Jacking System. This system consists of four vertically mounted cylinders, two on each axle, containing a piston or ram having 3.5" stroke. The cylinders, or jacks are connected up to a distribution box by copper pipes and flexible tubing. The distribution box is, in addition, an oil reservoir and contains a hand operated plunger pump and non return valves; it is mounted on the running board or on any other convenient spot. Operation of the hand pump, pumps Lockheed oil from the reservoir into either one of the jacks or into all four, according to the position of an indicator tap on the distributor box; | ||