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).
Failure of ferrules in fabric couplings, proposing rivets and bulged fabrics as solutions.
| Identifier | ExFiles\Box 19\3\ Scan297 | |
| Date | 12th April 1930 | |
| x7772. To Wob. from Oy. c. By.{R.W. Bailey - Chief Engineer} c. Hs.{Lord Ernest Hives - Chair} c. S.M. Oy1/DM.{D. Munro}12.4.30. Fabric Coupling. Sec.6000. In talking about fabric couplings it seems that the principle trouble is breakage of the little screwed ferrules attaching the plates. I am not quite sure whether By.{R.W. Bailey - Chief Engineer} has our latest prints on this, but following Hs{Lord Ernest Hives - Chair}' last report on the matter we went back to rivets for these plates. As we had fabrics already drilled 5/16" for the ferrules, we used a steel bushing to fill the hole and guide the long 3/16" rivet. (Dimensions are from memory). The bushing is about 1/8" shorter than the width of the fabric which we find too variable to allow of a shouldered rivet. The bushing, however, prevents the rivet from bending when rivetted. The fabric is powerfully squeezed between two star shaped plates before rivetting, so that the rivets shall be really tight. The rivets are headed over by machine. I cannot quote exact mileage, since we returned to rivetting without preliminary test as readoption of earlier practice. However, we know that the ferrules were failing under 2000 miles in many cases and the rivets are good for at least 10,000 without breakage. With regard to the use of bulged fabrics, while we agree that they are stiffer than the plain fabric in bending, we should imagine that they might be more flexible in torsion due to the 6 cores of rubber. We feel that the bulged fabrics, which undoubtedly resist breakdown on the compression side, should have a longer life than the plain with any type of driving pin. I think it is correct to say that the bulged fabrics have eliminated complaints on P.I. However, I should agree that the Experimental Dept's. "joggling" test should show up any benefit in the bulged fabrics very quickly. Maurice Oy. Olly | ||