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).
Design details and stress considerations for a 40/50 HP chassis front shock absorber ball pin attachment.
| Identifier | ExFiles\Box 78\2\ scan0129 | |
| Date | 4th June 1919 | |
| R.R. 235A (500 T) (S.D. 408. 26-4-17.) Bm. 2/156/13. E6/G4.6.19. To DA.{Bernard Day - Chassis Design} from E.{Mr Elliott - Chief Engineer} c. to CJ. c to Bn.{W.O. Bentley / Mr Barrington} c. to BY.{R.W. Bailey - Chief Engineer} c. to EH. c. to EFC. RE 40/50 H.P. CHASSIS - FRONT SHOCK ABSORBER X.3461. Pt. We send herewith drawing No. LeC.1101 as promised, illustrating the details of the ball pin attachment to the front axle for the above. After much consideration it was decided to provide no locking for the nut securing this pin. It was thought that the load would never reachthe degree of tightness to which the 1/2" nut would attain, and would therefore not be able to loosen it. The number of threads per inch should be 20, in accordance with our No.2 standard for fine threads. If any trouble should be experienced, however, with this but working loose, it should be castellated in the ordinary way, and two holes for the split pin should be provided in the bolt stem at 90°. This arrangement gives 12 positions in the circle, corresponding to an endway movement of the nut of .004" steps, which is too coarse to be satisfactory. Would you kindly compare the strength of the bending moment section along the stem of the ball pin with the strength of the screwed stem in tension, assuming, however, that the latter streess is not a symmetrical one, but is distorted by heeling off the edge of the ball pin flange. This commanication should complete the information required by you on this matter. E.{Mr Elliott - Chief Engineer} | ||