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 D.W.S. mechanical jacking system and its fitment.
| Identifier | ExFiles\Box 26\3\ Scan119 | |
| Date | 21th January 1932 | |
| -3- (7) Fitting the jacks to the rear axle necessitates altering the shape of our exhaust swan neck to accomodate them. (8) It is very difficult to let the car down off the jacks slowly. (2) The D.W.S. System. This system is entirely mechanical and consists of three jacks working on the lazytongs principle, two fixed under the rear axle spring clips and one under the centre of the front axle. The car is jacked up by means of a handle which is very easily connected up to the jack. The jacks themselves are very strong, exceedingly well made, do not look unsightly and are designed cleverly to exclude water and mud. We have not been able to damage them by rolling the car about when jacked up. The jacks are so designed that the handle is fixed to them at a position which will always be accessible no matter what type of body is fitted. The front jack is operated by inserting the handle between the wheel and the dumbiron, the rear between the periphery of the wheel and the mudwing, points where there must always be clearance. It is not necessary to assume a bending position when connecting the handle to the jacks or when operating the jacks. The handle itself contains a reduction gear by means of which the effort required to lift the car can be varied; the makers can supply either 6:1 or 9:1 gearing, the latter being more suitable for our heavy cars. Normally only one jack is fitted to the front axle, the makers claiming that two are unnecessary; if the car is resting on a big camber when jacking it is possible that one front wheel will not clear the ground; if however when this happens, the rear jack on the same side is operated, the wheel becomes clear of the ground. The great advantage of only one jack on the front axle is that it is carried exactly in the middle and thus any possible effects to the steering by increase of/weight are at a minimum. axle | ||