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).
Modifications to a gearbox and a spring to correct a 'shooting out' gear issue.
| Identifier | ExFiles\Box 66\4\ scan0214 | |
| Date | 28th October 1925 | |
| X8310 To Hs{Lord Ernest Hives - Chair} from RHC.{R. H. Coverley - Production Engineer} C PY RHC{R. H. Coverley - Production Engineer}11/BE. 28.10.25. RE EAC GEAR BOX With reference to the New Gear Boxes with the Improved Change Speed Lever mounted on Gear Box. These boxes are fitted with torsionally free 1st & 2nd speed Pinions. Trouble was experienced on 8.EX. due to the Gear( Shooting out). This was found to be due to in-sufficient clearance in the Acme Threads which meant that under certain conditions the Gears were not torsionally free. The detailed drawings for these pieces have now been modified so that when Gears are in position there is slack in the Acme Threads to the extent of .005 to .010, so that no further trouble should be experienced with Gears coming out providing future parts are manufactured in accordance with the latest drawings. The Spring E.73755 on Change Gear Shaft has also been modified, and since the modified spring has been accepted as satisfactory we suggest that the drawings should be altered. With the new Spring the effort required to move across gate is 6 lbs. Particulars of Spring are:- Free Length 6.375 - 17 SWG Wire - 12 Working Coils. 1 extra coil at each end making a total of 14 complete coils which gives a load of 7 1/2 lbs when compressed to 1.250. RHC.{R. H. Coverley - Production Engineer} | ||