J. and E. Hall, Limited.
Page 26
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Exhibit:—The " S.B. and S." Petrol-Electric Bus Chassis.
The " Hanford ". petrol-electric bus, Which has been running in the service of Thos. Tilling, Limited, of Peckham, has run upwards of 6,000 miles since it left the works of J. and E. Hall, Limited, of Dartford; during the time that it has taken to cover this distance, the vehicle has run completely to the satisfaction of its users. The machine in question was the subject of a paper which was read before the Society of Road Traction Engineers, on Monday evening last, by Messrs. Percy Frost;1-nith and W. A. Stevens, two of the gentlemen who were responsible for the design of the vehicle's transmission gear. A precisely similar chassis to the one to which we refer above is being shown by its makers.
The engine, and the genera/ details of the chassis, are made to the standard designs of the excellent " Hallford " petrol chassis, which gained a gold medal in the R.A.C. trials on account of its fine performance. The electrical transmission is, however, based on the " S.B. and S." patents. The dynamo is of the inter-polar type, and is directcoupled to the engine, by means of a special form of coupling which permits of a slight amount of errors in aligninent of the crankshaft and the armature shaft. The current from the dynamo is carried through a main switch, which is controlled by a pedal, to the series-parallel controller, and this is operated by a lever which takes the place of the change-speed lever of a vehicle with mechanical transmission. The controller lever is interlocked with the pedal, in such a manner that it is impossible to move the lever without depressing the pedal ; this action first throttles down the engine, and then breaks the connection between the Avnamo and the controller. From the controller, the current is taken to two series-wound motors, which are mounted at the opposite ends of a couple of transverse bridges, so that the motors stand clear outside of the frame, and are, therefore, in most accessible positions for cleaning and for adjustments. Brake drums are fitted to the armature shafts of the motors, and one of these is shown in our illustration, which also shows the simple and effective brake blocks and the actuating levers.
Each of the rear road wheels is driven, by its motor, through the medium of a worm gear, all the parts of which are completely enclosed and run in an oil bath, and the worm and wormwheel shafts are mounted on ball thrust and journal bearings. The inner wall of each of the worm-gear casings is formed of a -flange, which is forged solid with the " dead " axle; the remaining portions of the casings are bolted to these flanges, and thus form very stiff cases, which are well up to the requirements of the worm gears.