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).
Patent specification for improvements in change speed gears.
Identifier | ExFiles\Box 136\4\ scan0193 | |
Date | 27th December 1934 | |
RM{William Robotham - Chief Engineer}/GRY{Shadwell Grylls} + Fearbox General 1153 PATENT SPECIFICATION 449,540 Convention Date (Germany): Dec. 27, 1933. Application Date (in United Kingdom): Dec. 27, 1934. No. 37057/34. Complete Specification Accepted: June 29, 1936. COMPLETE SPECIFICATION Improvements in and relating to Change Speed Gears We, DAIMLER-BENZ AKTIENGESELL-SCHAFT, of Stuttgart-Untertürkheim, Germany, a German company, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:— This invention relates to a change speed gear and has for its main object to make the gear changing operation considerably easier and the gear as noiseless as possible. The invention further relates to a particularly suitable construction and arrangement of the means for facilitating the change of gear and of the whole gear itself. Gears with several noiseless speeds are for instance known, in which the speeds are formed by three pairs of toothed wheels which are always in mesh and are operated by means of two change-over clutches which are provided with dogs having inclined end surfaces and are changed over without a middle position of rest. This arrangement cannot, however, be used in all cases, since, when both change-over clutches are operated simultaneously, the re-engagment of the dogs which are inclined on one side may in some circumstances cause difficulties. For this reason auxiliary clutches have already been proposed, by means of which the disengaged parts of the gear can be reconnected with the engine or the vehicle. The invention overcomes this disadvantage, and consists in change speed gear, more particularly for motor vehicles, with means for facilitating the operation when changing speeds, in which the said means on movement of a control member in one speed-changing direction acts as a synchronising coupling (p₂) to bring rotary toothed members to like speeds prior to mutual engagement, and on movement in another speed-changing direction, the said means acts as a synchronising brake (p₁) to bring other rotary toothed members to like speeds prior to their mutual engagement. The invention also provides for a particularly suitable mode of operation. As the synchronising coupling a disc or cone coupling is preferably used, which is disposed at one end of the gear. This arrangement has the advantage that the coupling can be made as large as to make a really sufficient and effective synchronisation possible. The invention provides the further advantage that the arrangement for facilitating the operation of the gear is actuated by the gear lever through a lever linkage, while the dog clutch coupling coacting with it is moved by means of the gear lever without any interposed lever linkage. Owing to this the operative pressure produced on the means for facilitating the change of speeds can be considerably increased, without however, in spite of the increase in the effective operative motion necessitated thereby, the total operative motion becoming too great owing to the direct actuation of the dog clutch. The arrangement is preferably made such that at a certain resistance in the change-facilitating device, that is for instance after synchronisation has been effected, this device becomes automatically disengaged during the further operative motion and the new speed can be thrown in. In the accompanying drawing a constructional example of the invention is shown, Fig. 1 being a longitudinal section through the gear, Fig. 2 a cross-section on the line A—B of Fig. 1, which shows the arrangement for facilitating the change in elevation, Fig. 3 a cross-section on the line C—D of Fig. 2, Fig. 4 an elevation of the mechanism for actuating the front change-over coupling, Fig. 5 diagram of the mode of operation for the different speeds. In Fig. 1 a is the engine coupling shaft, b the Cardan shaft and c the lay shaft. On the shaft a is mounted loosely the toothed wheel d¹ which is in constant engagement with the toothed wheel d₂ which is fixed on the lay shaft. The same applies to the pairs of toothed wheels e₁—e₂ and f₁ and f₂, the toothed [Price 1/-] | ||