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).
Technical comparison of different gearbox mechanisms, listing advantages and disadvantages for each.
| Identifier | ExFiles\Box 6\4\ 04-page208 | |
| Date | 25th March 1929 guessed | |
| -2- Of those in Class C, only (12) is being used. Some of the others appear to present possibilities of an original arrangement being arrived at. We attach literature concerning : Salerni coupling, Synchro-mesh, Several arrgts. of internal mesh gears, Panhard helical 3rd. with dogs. The following are comments on the individual schemes : None of our competitors schemes entirely meet our requirements as they stand, but some seem capable of improvement. (2) EASY CHANGE ONLY - FREEWHEEL IN CONSTANT MESH WHEEL. ADVANTAGES. Easiest possible change down into any of the gears without operation of the clutch. The freewheel may be positively cancelled when desired, by a dog clutch. DISADVANTAGES. Change from 3rd. to 4th. is not improved but this is considered to be unimportant. Freewheel action is given on 1st. 2nd. and 3rd. We are uncertain how this will be accepted. (3) SALERNI COUPLING (Description enclosed). ADVANTAGES. Easy change up or down into all gears. Little increased cost and weight. DISADVANTAGES. The clutch control is made heavier owing to the clutch pedal having to operate the coupling after the clutch is free, and then to apply a clutch stop when the coupling is free. There are difficulties in the operation of the device which make us uncertain about the success of the scheme. The servo must be placed behind the coupling. (4) SYNCHRO-MESH. ADVANTAGES. A noiseless change between 3rd. and 4th. with practically no chance of a failure. Orthodox controls and gate, and little difference in manner of contd. | ||