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).
Fixing front springs to the front axle, identifying loose spring clips as the cause for broken bolts.
| Identifier | ExFiles\Box 54\3\ Scan006 | |
| Date | 1st April 1921 | |
| x2628 EP. {G. Eric Platford - Chief Quality Engineer} from BY. {R.W. Bailey - Chief Engineer} C. Da. {Bernard Day - Chassis Design} C. Hs. {Lord Ernest Hives - Chair} EY9-P1.4.21. x2628? FIXING OF FRONT SPRINGS TO FRONT AXLE. --------------------------------- Referring to EP {G. Eric Platford - Chief Quality Engineer} 17/F31321, the trouble is unquestionably due to the spring clips not being tight. Chassis 27-EW, from which the broken bolt was returned for my inspection, was an early chassis, and from what I can gather the Works were not tightening down the clips so that there was no gap at the front and rear end of the spring seating when this chassis was delivered. We brought this matter to the Works attention, and from an examination of recent chassis we feel certain that the clips are tight and that there is no gap at the point indicated before they are handed over to test, and this being so we cannot imagine the trouble recurring. If the spring clips were not tightened up in such a manner as to bring the bottom plate of the spring in contact with the extreme edge of the seating, both at the front and back edges of same, then under negative camber effects the spring would be loose and moving about - the plates would tend to slide over one another and it is precisely this sliding of the plates (which almost amount to the insertion of a powerful taper wedge) which breaks the bolt where the screw thread runs out, the break being in tension one in every case and not shear. From what I can gather we have only had a few instances of this fault, and I am inclined to think that they will be confined to earlier chassis, and therefore I do not think at the moment there is any need for us to set up a panic on this particular point, as in any case it does not represent an actual danger to life or limb. Our practice at the present is exactly similar to our prewar practice - there has been no change in the design of the spring seating, the packing which rests on same, or the bottom of the spring, and therefore since the trouble was non-existent in prewar days, and since also the postwar front spring is precisely the same, as the prewar front spring, I cannot see the slightest reason we should break bolts now when we did not break them in prewar days. BY. {R.W. Bailey - Chief Engineer} R. {Sir Henry Royce} - | ||