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).
Comparison of the Universal 'Scissor' Type Jack and the Dunlop Standard Bentley Jack.
| Identifier | ExFiles\Box 139\2\ scan0144 | |
| Date | 9th November 1934 | |
| To Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} +3117 Hs{Lord Ernest Hives - Chair}/Bwg.{J. C. Bowring}16/KW.9.11.34. Comparison of Universal Jack & Dunlop (Std. Bentley). "Scissor" Type Dunlop Universal Jack Std. Bentley Jack Weight. 8 lbs. 10 ozs. 6 lbs. 12 ozs. Handle Weight. 2 lbs. 3 ozs. 2 lbs. 13 ozs. Min. Height. 4.250" 5.500" Max. Height. 12.500" 12.500" Min. Length. 9.500" 7.250" Max. Length. 12.00" 7.250" Max. Lift. 8.850" 7.00" Tyre Ground 1.375" 1.375" Clearance The Universal Jack has very quick operation, probably faster than any portable Jack on the market. Operation is easy, raising and lowering a wheel which is inflated, but becomes extremely stiff raising a deflated wheel, this is due mainly to the friction on the operating thread caused by the angle taken up by the 'scissor' arms. This could be practically overcome by fitting a right and left handed square threaded shaft, such as that fitted by the D.W.S. Co. The Jack mechanism is very exposed to grit and other foreign matter which would soon tend to seize. Comparatively, the Dunlop Jack is more compact, and its easiness of operation remains constant and complete weighs 1 lb. 4 ozs. less than the Universal. | ||