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).
The difficulty of standardising a lifting jack and comparing permanent jacking systems with a simpler alternative.
| Identifier | ExFiles\Box 26\3\ Scan048 | |
| Date | 14th February 1929 | |
| Y 3117 S/W for (Hs{Lord Ernest Hives - Chair}) CWB/1/GD14.2.29. LIFTING JACKS. We appear to have considerable trouble in standardising a lifting jack, and as soon as we succeed in finding a suitable one, the makers appear to cease manufacturing it and we have to begin the search over again. Many attempts are also made to influence us fitting permanent jacking systems to the car, such as the "Stevenson" and more recently the "Mayfair" hydraulic jacks, in which system a permanent jack is fitted at each extremity of each axle worked by hydraulic means from a pump which is worked by a four way cock which is fitted on one of the running boards. We find that in practice it is almost impossible to fit these four jacks in these positions without interfering with some other portion of the car's mechanism, and from this point of view are against them as we presume you are also, from general technical considerations. It would seem in these days quite unnecessary to carry about such a weight of material for the very occasional use to which it is put. At the same time, on the few occasions when it is necessary to use a jack, it is far from easy to place this correctly under the car, and in this connection, I remember a jack, which I think Rapson introduced 10 or more years ago, in which the head was fitted with two pins, one on each side, which were hooked on to lugs fixed to the axle so that the placing of the jack in position was a very simple matter. Once hooked on as the inner member of the jack ran out freely until the jack reached the road surface, and all remained to do was to wind it up and so lift the car. This system appears to meet all the demands of the case. Is there any reason why we should not fit it as a standard, presuming that these special jacks are still obtainable? It appears to combine all the essential advantages of a permanently fitting jacking system without their disadvantages, and reduces the amount of tools and material carried for jacking purposes to a minimum. What are your views on this subject? CWB. | ||