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).
Clutch design, focusing on asbestos fabric rings, operating levers, and the development of high-friction fabrics.
| Identifier | ExFiles\Box 128\2\ scan0003 | |
| Date | 29th December 1927 guessed | |
| - 2 - The asbestos fabric ring is woven with four pockets fitting the ends of the four spokes. The fabric is impregnated, moulded, and die-pressed in position on the four spokes which are not attached to the fabric in any way but by the fit in the pockets. There are therefore no rivets in the disc. The spokes are attached to the hub without direct metallic contact by means of a ring of non-metallic material as shown. We are not clear whether this ring is supposed to have any flexibility. Its chief function seems to be to keep heat away from the hub. Operating levers are arranged tangentially, as shown. The peculiar construction of the levers requires certain slacks in their pivots etc. By their position all these slacks are taken up in one direction by centrifugal force, and there is no consequent clatter or jingling in the clutch. (4) FABRICS A large range of different fabrics are being developed by the makers with varying coefficients of friction so that a clutch of a given size can be made to cope with various engine-powers without excessive clutching-power such as would tend to give fierce engagement. Development of higher friction fabrics than have hitherto been attempted in single-plate clutches have enabled them to cut down the pedal pressure in most cars tested, from 30% to 50%. Makers quote tests up to 25,000 miles in Reo trucks, Franklin, Chrysler, Buick and others. They are about to manufacture S.A.E. standard clutches in quantity for various makers, and will also lease their royalties to manufacturers. Very truly yours, Maurice Olley MO/R | ||