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).
Comparison of the advantages and disadvantages of synchro-mesh and internal mesh with dog clutches gearboxes.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan050 | |
| Date | 25th March 1929 guessed | |
| (3) (4) SYNCHRO-MESH. ADVANTAGES. | DISADVANTAGES. ---|--- A noiseless change between 3rd. & 4th. with practically no chance of a failure. | Some doubt as to durability of cone clutch surfaces. Orthodox controls and gate, and little difference in manner of their operation required. | Outer cones are always rotating at engine speed in the stationary control piece although no load is being transferred except during changing gear. Failure of the synchronising mechanism interferes very little with the operation of the car. | Small increase in gearbox length. Increase of cost and weight is small. | (5) INTERNAL MESH WITH DOG CLUTCHES. Quiet 3rd. | Gears cannot be ground, and may vary in quietness. Reports on boxes of this type refer to the changing of gear as particularly easy, but we see no reason why this should be so. | Internal mesh gears are always in mesh. No great amount of extra cost or complication. | Some addition to spinning mass which makes the change into 2nd. more difficult. Orthodox controls and gate, and no difference in manner of operation. | Considerable increase in length of gearbox. There appear to be two main types of this gear - (A) with the internal mesh unit in front of the lower gears, (B) with the constant mesh gears at the front, and a long layshaft reaching across the internal mesh unit to the lower gears at the rear. The Detroit Gear & Machine Co's designs are examples of type (A), and the Warner Gear of type (B). Descriptions of both are enclosed. The Detroit gear has an internal mesh unit mounted as shewn in sketch (on the next page.) The control against rocking appears to be derived from the fit endwise. The forces on the ring gear are in the same direction so that there is no tendency to rock the gear. | ||