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).
Analysing potential causes of failure in a steering system, focusing on loads, forces and design flaws.
| Identifier | ExFiles\Box 153\4\ scan0147 | |
| Date | 20th May 1943 | |
| [Handwritten]: Chassis [Stamped]: To Mr. Rm.{William Robotham - Chief Engineer} [Stamped]: 1300 By.3/EP.{G. Eric Platford - Chief Quality Engineer}20.5.43. STEERING. I would like to confirm that the only point in regard to the steering I have basically argued is that it as a whole is irreversible, by this I mean there are no road wheel movements and forces which make the steering wheel "joggle". The next point I am now clear upon is that there is a much greater torsional load on the pendulum lever than I had imagined, as in the absence of drawings I decided that the bend in the pendulum lever was to bring the centre of the ball in line with the vertical plane in which the lever enters the boss at right angles to the working axis, this however is not the case, the ball projects on the side of the bent lever away from the bend and so increases the torque on the lever. [Initialed]: Jm{Mr Morley} The third point which arrests attention is that side blows on the near side road wheel behind the centreline of the wheel would result in tension on the pendulum lever at the point where the crack develops, in a similar way on the off-side wheel it would be a blow on the front, but as one is more often near the curb on the left-hand side I think this explains the position of the fault and its persistance in being in one place. The fault is obviously not due to either :- (a) Parking effects as this would stress the levers equally on either hand, there being no particular reason why all the cars should always be parked with excessive loading in one direction from the point of view of mere parking. (b) Normal road shocks - these are generally speaking negligible and again if a car were driven over a very bad road the impacts would be likely to occur on either road wheel, our experience is that impacts of this nature do not cause failure as demonstrated on the Phantom III. The fourth point I wish to settle by having an arrangement of the steering lever system, is are there springs in the system with the object of reducing shock load? and if so where. In this connection Mr.Dodd says there are no springs in the coupling rod from the pendulum lever to the lever mounted across the chassis and from an external view of the coupling I think he is right, but this can be settled beyond question when I get the arrangement referred to above. continued | ||