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).
Page discussing irreversible steering systems, including a graph on screw and nut efficiency.
| Identifier | ExFiles\Box 178\1\ img105 | |
| Date | 13th July 1926 guessed | |
| - 6 - nut becomes self-locking with a helix angle of 6°. This clearly demonstrates the difficulty of protecting a driver from road shocks and at the same time giving him finger-light steering on a large car. GRAPH II EFFICIENCY % SCREW f = 0.10 HELIX ANGLE DEG. TYPICAL CURVE INDICATING POINT OF IRREVERSIBILITY OF SCREW & NUT. (3) Irreversible. These are usually worm wheel and segments or screw and nuts where helix angle is carried beyond the semi-reversible stage. They allow no shock to be transmitted to the driver. On the other hand they allow no self-centering so that the driver must always be steering the car. They are not selective. As all the road shocks have to be taken up in the steering gear, there is a risk of breakage. Longitudinal buffer springs cannot be fitted in the side steering tube because of low speed wobbles, thus wear is likely to take place in the reduction gear under the constant hammering which occurs. Being irreversible, the steering is necessarily somewhat inefficient. contd. | ||