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 redesign of a pivot, including stress calculations and instructions for new parts.
| Identifier | ExFiles\Box 80\1\ scan0044 | |
| Date | 15th February 1916 | |
| -2- E8/C30718. section between the pin and the pivot. we have removed the feature which formerly spigoted the tin guard. This must now be correctly placed by means of a jig, and dowelled with the aid of the pins shewn. The guard is now secured by four countersunk screws which drag the material into the countersinks. The countersunk screws should be made from square material with a neck which is twisted off. This will give us a more secure job than we should otherwise obtain with screw driver slots. The drawing shews stress curves based on a bending moment due to a load of 12½ cwts. applied vertically on the front wheel, and a slurring load equivalent to a coefficient friction of one between the wheel and the road, which imposes a lateral load at the edge of the tyre of 12½ cwts. We have neglected the shear and tension due to this load, and the tension due to the tightening up nut, since we think the amount of calculation done sufficiently demonstrates the alteration we have made. Mr. Royce wishes you to put in hand a pair of these pivots for the Duke of Westminster's car, and to put in hand a further pair for a destruction test, which will tell us quantitatively how much better the new pivots are. Referring further to the Duke of Westminster's car it should be arranged that the cross tube should be altered to have the latest fitting recommended for use, if this has not already been carried out. The new pivots, so far as we know, will be applicable to this car, and will bestow on it the Contd. | ||