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).
Analysis and description of the Maybach four-speed easy-change gearbox, including operational diagrams.
| Identifier | ExFiles\Box 22\5\ Scan033 | |
| Date | 2nd March 1931 | |
| -2- (6) It is always necessary to release the accelerator pedal on the Maybach cars we have tried, before the dogs can dis-engage and a change down be made. They therefore apparently do not use their patented scheme. (7) All the Maybach changes we have tried have had a vacuum servo to do the actual toggling on the box. They have altered their first arrangement A.{Mr Adams} to a simpler spring operation B. [DIAGRAM A & B] We attach a sectional drawing of the latest Maybach four silent speeds four easy changes gearbox which is self explanatory. In effect it is two Maybach clutched systems with a small single speed gearbox behind and in series with them. The single speed gearbox is controlled by an ordinary hand lever and the car clutch, and gives a neutral position and a dogged up drive position. On the same side of the gate is a third position which is a super low gear for unditching purposes but can actually be combined with any of the other silent three speeds to give unsilent combinations in a lower ratio of 4.5:3 of the normal gears. Actually of course these ratio are not used. Passing through the gate a reverse shaft is brought up and reverse is obtained which is of course used in bottom gear ratio but can equally well be either of the three other forward ratios. [DIAGRAM OF GEAR GATE] R N EXTRA LOW 4.5-1 1-1 DIRECT NORMAL 1ST RUNNING One would naturally expect trouble changing from third to second or from top to bottom but actually the box works quite well and we do not think would be troublesome in the hands of the public. Considering the multiplicity of its ratios it has commendably few parts. The gear lever so seldom used can of course be reduced in size. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} | ||