Patent GB-150908-A (GB)
Title: Improvements in electro-mechanical variable-speed and reversing mechanisms
IPC: H02P5/695
Filed: 1919-10-06
Abstract: 150,908. Anciens Etablissements Barbier, Benard, et Turenne. Oct. 6, 1919. Dynamos and motors combined for transmitting power.-Relates to variable speed transmission mechanism comprising electric motors and generators. The driving-shaft is connected to the driven shaft through differential or epicycloidal gearing, one element of which is actuated by an electric motor through non-reversing gear. The motor is fed from a generator geared to the driving-shaft and is controlled by means such as a rheostat switch so that it runs at any required speed and thereby causes any required transmission ratio. The motor, generator, and system of gear-wheels may form an enclosed unit. When the prime mover is an internalcombustion engine, a battery may be provided to enable the motor to act as an electric starter. Figs. 1 and 6 show an apparatus comprising an electric motor, generator, and starting-battery for use with an internal-combustion engine, where only a unidirectional drive is required. A shaft 2 carrying a mechanical coupling 3 by which it receives power from the engine is geared to a dynamo 4 through a worm and worm wheel. Keyed on the shaft 2 is one wheel 11 of a differential train of which the opposite wheel 10 is geared through a worm and worm wheel to an electric motor 7. The intermediate wheel 12 is keyed on the shaft 15 to which variable speed is to be imparted. Both the generator and the motor are shown as compound wound machines and by means of a rheostat switch a, the shunt field of the motor is varied as desired. By thus increasing the speed of the motor to equal that of the power shaft 2, the intermediate wheel 12 and with it the driven shaft 15 may be reduced to rest. In order to start the engine, a battery 38 or other independent source of current can be switched on to the machines 4 and 7 through a contact 24. The motor, generator, and gearing are enclosed in a case 1. A modification having epicyclic gearing in place of differential gearing is described. A more complete apparatus providing for forward and backward drive, as in motor-car propulsion is shown in Fig. 8. The shaft 50 which receives power directly from the prime mover has keyed on it a double bevel-wheel 52 common to two differential trains. One wheel 53 of the left-hand train is in gear through a worm, worm-wheel, and bevel-wheels 59 with the shaft of a dynamo-electric machine 57 which can work either as a generator or a motor. The intermediate wheels of the left-hand train are mounted in a spur-wheel 69 geared through a countershaft (not shown) and a spur-wheel 74 to a third differential train 77. The right-hand differential train of the two that are in gear with the double bevel-wheel 52 is similarly connected. but without the use of a countershaft, to a machine 58, similar in character to the machine 57, and to the third differential train 77. The intermediate wheels of this train impart movement to the shaft required to be driven, this movement being forward or backward according as one or the other machine is running, and being zero if 'both machines are running at equal speed. The operation is controlled by a hand switch B, Fig. 13. In order to provide for starting the engine, the shafts of the machines 57, 58 are fitted with electro-magnetic clutches 89, 91 which transmit motion through the bevel gear 59 as long as the electro-magnet is energized. When this is deenergized one shaft is automatically clutched to a spur wheel 81 in gear with the wheel 52, and similarly for the other shaft. Before starting up and with the switch B in the mid-position shown in Fig. 13, the electro-magnets of both clutches 89, 91 are out of action. When the switch D is closed for starting the engine the electro-magnets are not affected and both machines receive current from a battery G. so that they operate as motors to drive through the spur-wheels on to the shaft 50 without moving the car-axle. When the engine is started, D is opened and B is moved either to the left or right, causing one or other of the clutches to act so as to couple the corresponding machine through its bevel-gearing. The other machine is simultaneously connected up as a generator and is directly driven by the wheel 52. Subsequent movement of B varies resistance in the motor shunt field and thus varies the transmission ratio as described above. A further modification in which epicyclic gearing is substituted for differential gearing is described. During the time that the machines are functioning as generators, they may be used for lighting purposes. The invention is stated to be applicable for the propulsion of railway-trains, ships, and aircraft, manipulation of lifts, rudders, turrets, and heavy artillery,. control of search-lights, beacons, signal lights, and actuation of machine tools.