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).
Page from the 'Engineering' journal describing a single-lever control system for motor-cars.
| Identifier | ExFiles\Box 156\4\ scan0021 | |
| Date | 18th November 1927 | |
| Nov. 18, 1927.] ENGINEERING. 659 SINGLE-LEVER CONTROL FOR MOTOR-CARS. CONSTRUCTED BY MESSRS. AKTIEBOLAGET SPONTAN, STOCKHOLM, SWEDEN. Fig. 2. Fig. 3. Fig. 4. Fig. 5. (376.B.) Fig. 6. GEAR-BOX IN POSITION IN CAR. transmission shaft. Such a motion involves the revolution of the planet wheels about their own axes, the rate of revolution depending upon the required difference in speed between the driving and driven shafts. The actual difference is established by the relation that, frictional losses being neglected, the torque multiplied by the angular velocity must be the same on the two sides. When the planet wheels commence to revolve, the balance weights will be carried towards the common centre, a movement which will be opposed by the centrifugal force on the weights during half a revolution, and assisted by the same force during the second half. In their inward motions, therefore, the weights must be absorbing energy from the engine, this energy being given out again on their outward motion. Since the turning moment on the sun wheel will be alternately positive and negative, according to whether the weights are moving outwards or inwards, means must be provided to transmit the drive to the propeller shaft during the incidence of the positive moment, and to afford an anchorage to a non-rotating element, such as the casing of the gear-box, during the incidence of the negative moment. The method by which the fluctuating impulses are transferred to the propeller shaft can best be elucidated by reference to the gear as actually applied in practice. Various views of the apparatus, as fitted to an 11-h.p. Fiat car, are given in Figs. 2 to 12, on this page and on page 660. Referring first to Fig. 2, it will be observed that the sun and planet wheels are replaced by a system of eccentrics. A sleeve, concentric with the propeller shaft, carries three eccentric discs at the right-hand end, as viewed in the figure, and the weights embrace the discs by means of ball-bearing rings, as shown in Fig. 5. The two outer eccentrics are equivalent to a single eccentric, as the sheaves are coupled together by one of the weights, the arrangement shown being merely adopted to avoid the introduction of a rocking couple. The weights are connected to the flywheel of the engine by pivoted links, which can also be seen in Fig. 9. A photograph of the weights and eccentrics is reproduced in Fig. 11, and other details are shown in Figs. 7 to 10 and 12. Again referring to Fig. 2, it will be seen that, in addition to the sleeve carrying the eccentric discs, there are two shorter inner sleeves, one of which, shown to the right in the illustration, is coupled to the driven shaft, while the other is connected to a second wheel, embracing a spring coupling. A second flywheel is provided, mounted on the driven shaft. Between the outer and each inner sleeve, there is a set of rollers, the inner sleeves being provided with inclined surfaces in such a way as to form a mechanical valve, or one-way clutch, of the usual type. In passing, it is of interest to mention that this type of valve was first patented, about 35 years ago, by the inventor's brother, Mr. Birger Ljungström, who is known internationally as the designer of the Ljungström turbine. The reverse motion for the car is obtained by having two inclined surfaces, facing in opposite directions, on the inner sleeves. The rollers are carried in cages, as shown in Figs. 8 and 9, and these cages can be turned in relation to the sleeves so as to bring one or other of the inclined surfaces into engagement with the rollers. Lugs on the end flanges of the cages engage with slots in a central member, shown immediately surrounding the transmission shaft at the centre in Fig. 2. This member, which can also be seen between the roller cages in Fig. 8, can be moved axially, but is prevented from rotating; it is connected by the pins shown in Fig. 2, passing through slots in the outer sleeve, to an outer member provided with a flanged ring carried on ball bearings. A pin mounted eccentrically on the end of the reversing spindle engages with the flanged ring; the arrangement being shown in Fig. 3. It has been mentioned that the left-hand inner sleeve is attached to a wheel immediately adjacent to the transmission flywheel. This wheel, which acts as a pendulum, is illustrated in the photograph reproduced in Fig. 12, and is shown in section in Fig. 4. It will be observed that it is connected to a central ring by six radial springs. It has an outer and inner rim, as shown in Fig. 12, the inner rim having a ring of teeth with which a pawl, not shown in the illustrations, engages. This pawl normally prevents rotation of the ring and forms part of an operating device which is employed when changing from forward to reverse, or vice versa. By means of a system of levers and cams, terminating in a shaft coupled to the reversing spindle shown in Fig. 3, the pawl is lifted for a short period, and then returned into engagement with the teeth on the ring, when the spindle is moved. The object of the arrangement is momentarily to free the pendulum wheel, and consequently the sleeve to which it is attached, to facilitate the reversal of the locking devices. This is of particular importance when, for example, a car provided with the gear is stopped on a hill. In such circumstances, the contact | ||