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 description of the Spontan roller clutch mechanism and its operation.
| Identifier | ExFiles\Box 41\4\ Scan039 | |
| Date | 21th September 1931 guessed | |
| SPONTAN ing surfaces of the inner and outer sleeves being provided with inclined surfaces so as to form wedge-shaped spaces for the rollers to work in. By means of springs the rollers are kept wedged into these intermediate spaces, thus forming an inner and an outer roller clutch of usual type, capable of Fig. 2. Diagram Labels: 3. (pointing to outer assembly) Springs Roller cage Reaction Sleeve Reaction Clutch Rollers 1. (pointing to middle assembly) Main Driving Sleeve Driving Clutch Rollers 2. (pointing to inner assembly) Driven Sleeve on Propeller Shaft transmitting a turning moment in one direction but automatically declutching and freewheeling in the other direction. At low speeds of the car the main driving sleeve receives turning impulses in alternate directions as already mentioned. Half the number of these impulses, acting in the "positive" turning direction of the engine, cause the driving clutch to engage and are thus transferred to the propeller shaft which carries a flywheel in the shape of a brake drum for transforming the intermittent impulses into an even driving torque on the back axle. All turning impulses acting in the other, "negative", direction are "freewheeled" by the driving clutch and, therefore, have no action on the propeller shaft. They must, however, be checked, and for this purpose the "reaction" clutch, engaging the opposite way to the driving clutch, is provided outside the main driving sleeve. This clutch transfers all negative turning moment impulses to the reaction sleeve but freewheels all positive impulses. The tendency of the reaction sleeve to turn in a negative direction is checked by a number of tension springs which form a flexible anchorage for this sleeve to the gear casing, thus preventing vibrations being transmitted to the car frame. In order to make the action of the intermittent impulses from the clutch smooth the reaction sleeve is provided with a flywheel, called the pendulum wheel, on account of its oscillatory movement. It will hardly be necessary to mention that the negative turning moment impulses do not represent any lost engine work as they act on the stationary reaction sleeve, and therefore cannot produce any mechanical work. It should be noticed that this action of the clutches takes place only when the propeller shaft cannot turn at the same rate as the engine due to heavy resistance (i. e.{Mr Elliott - Chief Engineer} starting, accelerating, climbing). During normal running "on direct drive", when the propeller shaft speed is equal to the engine speed, we have seen that an even turning force is produced by the rotating bob weights and is then transferred to the propeller shaft by the inner clutch, the outer clutch freewheeling all the time. There is nothing to prevent the propeller shaft from turning at a higher rate than the engine, freewheeling then taking place in the inner clutch. This is what happens when the car is coasting. If the car is stopped while going uphill, the tendency of the propeller shaft to turn backwards is transferred through both clutches to the pendulum wheel which is prevented from turning by the tension springs. Hence there is no need to apply any brakes to keep the car from running backwards. It will be seen from Fig. 2 that the inner and outer sleeves are provided with two sets of inclined surfaces facing in opposite directions. By bringing the rollers into contact with the other set of surfaces the driver changes the engaging direction of the clutches and the oscillatory tendency of the | ||