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).
Assessment of a large screw jack and a hydraulic jack, finding the hydraulic jack unsuitable due to its dimensions and oil leaks.
| Identifier | ExFiles\Box 52\4\ Scan043 | |
| Date | 4th March 1931 | |
| - 2x - Hs {Lord Ernest Hives - Chair} /Lid. {A. J. Lidsey} 8/KT.4.3.31.cont Large Screw (1st lift) Appears O.K. The jack certainly is not as easy to use as the average present standard Dunlop jack; we see no reason why we should change. Hydraulic Jack. This has the following dimensions, it is unsuitable for either of our cars; the minimum height is too great and the hydraulic lift not sufficient. Minimum height 7.375" Initial hand adjustment 3.812" Hydraulic lift 5.125" Maximum extended height 16.312" This jack was tested in the same manner as the screw jack and gave fairly satisfactory results. It is quite easy to operate, the only criticism being that it is necessary for the handle to be completely at the bottom of its stroke before the release can be used; if it is not at the bottom and effort is made to push the handle through to operate the release valve, the release valve is opened by the action of pushing the handle through into position and not as intended by the design. Oil leaks both from the top gland and from the release valve operating plunger. We have not dismantled this jack for examination as its dimensions rule it out for use on either of our models. Hs {Lord Ernest Hives - Chair} /Lid. {A. J. Lidsey} | ||