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 notes on rear springs and front shock absorber anchorages for the 40/50 HP chassis.
| Identifier | WestWitteringFiles\D\May1920\ Scan41 | |
| Date | 18th May 1920 | |
| To HS.{Lord Ernest Hives - Chair} DA.{Bernard Day - Chassis Design} & BY.{R.W. Bailey - Chief Engineer} -3A EL/G18/5/20 Contd. This forging should be got in hand at the earliest possible moment. Further, Mr. Royce wishes Mr. Hives to test a 2½" dia-meter pipe between the silencers with a view to replacing the present 3" pipe, which is very difficult to bend to the shape re-quired, and with a view to obtaining more clearance round the cut-out. REAR ROAD SPRINGS (40/50 H.P.) X.2628b. X.4056. The model submitted by Messrs. Firths of the rear road spring for the 4/50 H.P. chassis representing our latest require-ments was shewn. This model still seemed to have, to some extent, the defect of bedding on the leaf points, and Mr. Royce would like this eliminated. Further, it was considered by Mr. Royce that all the subsidiary plates should spring away from the bottom plate in the position of rest, so as to give the leaf which takes the side load an easier duty to do in bending moment. Mr. Royce wishes the springs with square ends to the plates to be pushed through the bumping test as soon as possible, and agrees to early standardisation, and instructs DA.{Bernard Day - Chassis Design} and HS.{Lord Ernest Hives - Chair} to ask Mr. Johnson for his agreement on this point. Each leaf point of the road spring carries a load equal to the load of the spring end, and Mr. Royce does not advise the shearing, but he recommends the square end tapered in thickness, together with what advantage can be obtained by varying the taper. The points of the spring plate require making a little too long, and a little too flexible. It was finally thought that the ends of the leaves should be straight tapered to some proportions, as the straight taper will naturally have a weak spot part of the way along the cantilever, and the effect will be to distribute the load at the end. In connection with this matter of rear springs, Mr. Bailey is to look into the height of the 40/50 H.P. chassis frame from the ground level with standard wheels. Mr. Royce has the impression that this height has grown to about 26", when it should be a little over 24". FRONT SHOCK ABSORBER ANCHORAGE (40/50 H.P.) X.3461a X.3763. The reason for this part coming loose on chassis 1 EX was investigated. The use of a spring washer for locking the nut on this anchorage is unsuitable. It is not easy to apply a split pin lock on account of lack of flexibility in the anchor-age stem, and it is not possible to rivet up as the nut must be removable to allow access to the front spring "U" bolt attachment to the axle. It was therefore decided to slightly modify the design so that the alternating load due to the shock damper will be resisted by two cones, one on the collar of the sphere, and one on the nut, as illustrated in the sketch - | ||