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).
Efficiency tests of a Steering Nut with Reduced Surfaces compared to a standard nut.
| Identifier | ExFiles\Box 20\2\ Scan119 | |
| Date | 22th November 1933 | |
| X963- To D.B. & Hs.{Lord Ernest Hives - Chair} from RHC.{R. H. Coverley - Production Engineer} C.E. EV.{Ivan Evernden - coachwork} STEERING NUT WITH REDUCED SURFACES. N.SCH.3759. A Worm and Nut has been produced in accordance with the above scheme, and tested on the rig in order to determine the effect on efficiency and general behaviour of nut due to reduction in thread area. Efficiency tests gave the results shewn in the following table, which also gives comparative figures for a standard worm and nut. Generally speaking, the torque required to lift a given load was 50% in excess of that required with a standard worm and nut under similar conditions. APPLIED EFFORT |-------------------------|-----------------------------|---------------------------| | AXIAL LOAD ON NUT (LBS) | NUT WITH RED:SURFACES | STANDARD NUT | |-------------------------|-----------------------------|---------------------------| | | Pull in lbs at 20° rad: | Efficiency | Pull in lbs at 20° rad: | Efficiency | |-------------------------|-------------------------|------------|-------------------------|------------| | 200 | 2.00 | 57.28% | | | | 300 | 3.125 | 54.98% | 2.00 | 85.92% | | 400 | 4.125 | 55.55% | | | | 600 | 6.00 | 57.28% | 4.20 | 81.85% | | 800 | 8.125 | 56.39% | | | | 900 | 9.00 | 57.28% | 6.00 | 85.92% | | 1200 | 12.00 | 57.28% | 9.00 | 76.38% | |-------------------------|-------------------------|------------|-------------------------|------------| It was observed that whatever the load, the nut could be made to stick by fidgeting it backwards and forwards on the worm, but not, however, by just bringing it to rest in the ordinary way. cont'd.{John DeLooze - Company Secretary} | ||