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).
Auxiliary springs, specifically the J.M. and Thompson types, and the development of fabric and rubber shackles.
| Identifier | ExFiles\Box 178\1\ img187 | |
| Date | 28th August 1926 guessed | |
| - 15 - As the inter-leaf friction still remains with this device it is not very satisfactory for increasing low speed riding comfort. The other type of auxiliary spring is represented by the J.M. and Thompson. These reduce the rating of the main spring for small deflections. Unfortunately if the main load is increased above normal they are likely to come choc a-bloc. They also promote side sway and axle bouncing when braking. There is no doubt, however that for slow speed work on fairly good roads this type of accessory undoubtedly improves the riding of the majority of cars fitted with leaf springs. (c) Fabric and rubber shackles. The normal type of spring shackles is not a very satisfactory arrangement. It requires constant attention for lubrication, wears rapidly and becomes a source of squeaks and rattles if neglected. Experiments have been going on for about 5 years to find a substitute for the conventional shackle. The 'rubber' shackle was the first to be marketed and consisted of a large mass of rubber constrained in a casing, in which was embedded the end of the spring. This has now been used on Mack trucks for over four years. contd. | ||