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).
Letter from Smith's Jacking Systems Ltd. regarding the design of Hydrolift jacks, specifically the issue of air expansion.
| Identifier | ExFiles\Box 140\2\ scan0201 | |
| Date | 13th May 1939 | |
| 116b. SMITH'S JACKING SYSTEMS LTD TELEPHONE GLADSTONE 6671 & 6672 TELEGRAMS: TOGGLE, GOLD CABLEGRAMS: TOGGLE, LONDON JACKALL-D-W-S-STEVENSON JACKALL WORKS EDGWARE ROAD LONDON. N.W.2 SJS DIRECTORS A.{Mr Adams} GORDON SMITH, CHAIRMAN DONALD W. SESSIONS GEN. MGR. C. W. NICHOLS, R.{Sir Henry Royce} GORDON SMITH Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls}6/MH{M. Huckerby} 13th May, 1939 Messrs.Rolls-Royce Ltd., D E R B Y. Dear Sirs, For the attention of S.H.Grylls, Esq. We thank you for your letter of the 12th inst. and note that you have despatched the aluminium bronze jack brackets for the six special Hydrolift jacks we are making for you which, incidentally, are progressing favourably. With regard to the last paragraph of your letter concerning the expansion of air in the jack, we are afraid the addition of a filler in the top of the container would not overcome this difficulty. For the proper working of the jack, it is necessary to have an air space in the top of the container, otherwise an air relief valve would have to be introduced which fitting always ends in leakage, and has been responsible for giving portable hydraulic jacks of the older type, a bad name. If the extra air pressure expanding in the container gives trouble, a longer container is a solution but so far we have been able to cater for this in the space allowed. Yours faithfully, For SMITH'S JACKING SYSTEMS LIMITED. Donald W. Sessions Director & General Manager. DWS/IKS | ||