RECENT ADVANCES IN ELECTRIC VEHICLES.
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Contrary to the Opinion Prevailing amongst the Advocates of the Internal Combustion Engine, the Electric Vehicle has been Making Steady Progress towards Efficiency.
By Raymond J. Mitchell, M.LE.E., M.LA.E., etc.
OMPARED with the spectacular advances now taking place in the internal-combustion-engined vehicle branches of the automotive industries, progress in the field of the accumulator-electric vehicle may seem negligible. These notes—for the information concerned in which the writer is indebted to the firms mentioned —should, however, serve to show that the quiet perseverance which has kept alive the electric vehicle idea has, by no means, permitted apathy or discouragement to deflect its aim, which is that eventually all town transport shall be brought within its scope. Although this ideal is not yet within even distant sight, yet, with the ever-increasing spread of the electrical method, both in industry and domestic affairs, it seems,to the writer inevitable that the natural trend of evolution will, in the long run, favour electric vehicles as being the perfect type of utility transport machine on roads.
New Light Electrics.
It has been assumed that accumulator vehicles can only be of use for heavy loads at low speeds, say around 10 m.p.h., and that light delivery service is, consequently, outside their scope. This fallacy arises from several misconceptions, chief of which is that touring car speeds are of commercial use in light delivery work—which, of course, they are not. A light delivery van which can travel at a top (average) speed of from 18 m.p.h. to 20 m.p.h., coupled with the very high acceleration inherent in the electric, will answer all c38 speed requirements for town deliveries, a range which is well within the gamut of this type of car.
Preliminary details of a specially designed light electric van (Fig. 1) show that in the Auto-Electric a considerable advance has been made underseveral headings which conduce to better performance both mechanically and in an economic sense. The delivery van shown is designed for normal loads of 7i cwt and maintains a speed of from 18 m.p.h. to 20 m.p.h. on hard, level roads. Regarding Its design, there are several points of novelty and decided improvement over previous practice. The chassis frame and battery compartment form a combined unit structure, giving the effect of a frame side member 13 ins. deep. This unit is combined with front and rear frame-member extensions of channel section braced by tubular crossmembers and stiffened by tie-rods passing right under the battery box from front dumb-iron to the rear end of the chassis, thus forming a very light but stiff frame and battery box combined.
Long semi-elliptic springs are employed mounted inside the frame yet with an exceptionally wide tread giving great sideways stability and allowing mudguards to be mounted directly on the frame members, thus eliminating forged stays and reducing the projection of the mudguards into the body space.
The steering gear is operated by a tiller. on . which is mounted t h e controller, giving, by a twisting motion of the hand, three forward a n d two revere speeds, in addition to a powerful electric brake in two stages. The tiller may be swung out-. board, thus allowing the driver to control and steer the van by walking alongside it when it is required to move only a few yards during a delivery round.
Worm final transmission through a cardan shaft is used, the motor being of specially light design, shunt wound, with provision for warning the driver to work on a lower speed controller notch should the current in the armature circuit exceed a certain permissible maximum value. This condition would only occur up extremely severe gradients which would rarely be met with, such as some of the short freak hills to be found in some northern cities. The battery is a 20-cell D.P. of 160 á.h. capacity.
The net weight of this little chassis is surprisingly low—only 7i cwt. for the complete machine, less battery and bodywork. An ample body space is available7 ft. 6 ins, behind the driver's seat, with a width of 4 ft. and an inside height of 4 ft. 4 ins. A further space alongside the driver's seat enables articles up to 11 ft. in length to be carried inside the body without projection.
A very light but strong body includes a number of novel features Which will appeal to any user needing to distribute parcels and consignments of light goods, Fig. 3.—Showing double reduction system in rear axle of accumulator electric delivery van. such as drapery, grocery and domestic deliveries generally.
Au interesting example of an American design of light delivery van chassis is shown in Fig. 2, in which the general design is very clearly shown.. This chassis follows conventional practice, excepting that the transmission unit represents a break away from routine in that not only is the motor attached to a flange forming an extension of the rear-axle casing but the speed reduction to the drive shafts is carried out in two stages, first by double helical gears, then by spiral bevel (Fig, 3). 'A light high-speed motor is thus made possible, the motor weight being taken by suspending it in a yoke which gives it freedom to move as required by the flexing of the road springs. Nothing other than this example could better illustrate the clean mechanical design which is possible in an accumulator vehicle.
That Great Britain is well to the fore in this field is sufficiently shown by the illustration of Garrett's latest design of electric vehicle chassis (Fig. 4), incorporating every feature of proved value by which performance may be enhanced, including worm gear final axle drive, twin brake system interlocked with controlling gear, and a controller giving eight speeds either forward or in reverse. The very robust design, coupled with lightness, which characterizes the chassis offers an immense contrast to the chain-driven and extremely heavy designs which used to be practically standard practice in the electric vehicle field.
With an immense Improve ment in many of our roads which has taken place since the war, there has developed a vastly increased interest in the socalled tracklesstrolley type of electric vehicle. Messrs. Garrett have taken a prominent part in this development, as is indicated in Fig. 5, the illustration showing a type of singledeck trolley omnibus of which 15 are on order for the Ipswich Cor
pora Lion. The vehicles will be of the 30-seater type, and include a special type of step-by-step control, ensuring jerkiess acceleration ; also air brakes of the Westinghouse type. Those who recall the pioneer trackless-trolley efforts in this country will, on comparing them with this machine, realize that an immense progress has taken plaee in this field. The w-riter considers that trackless-trolley progress will 'assist the development of pure battery traction, as the value of smooth, jerkless travel is experienced by more and more people and compared with other types of passenger Vehicle wherein, even to-day, neither smoothness nor absence of jerkiness is by any means apparent! Noise and vibration are also matters on which the public are very likely to become much more critical.
Battery Transport Assists in Mines.
How to replace the pit pony in mines has been a problem for many years. Accumulator vehicle experience has been turned to good account by the recent competition for a battery mine locomotive held near Doncaster. The winning locomotive (Fig. 6) will doubtless prove to be the prototype of many hundreds of such machines in mines during the next few years. The locomotive shown can exert a temporary pull of nearly a ton or a steady working pull of 600 lb. at 3.5 m.p.h., and thus replaces several pit ponies and travels faster. Special provision for every element of safety has been provided for In this design, Including wire gauze battery-box gas valves, totally enclosed motor, wiring and control gear, also means for quickly replacing or removing discharged batteries when required. Durability and high mechanical efficiency are ensured by using Hoffmann anti-friction bearings on motor shaft, worm shaft, axle components, axles, and even in the eyes of the connecting rods. By simple organization battery locomotives can thus be kept at work practically continuously, ensuring not only econo mica in mine working, but greater safety, perfect cleanliness of mine roads, and a speeding up of output without extra exertions on the part of the miner.
Mr. A. J. Makbwer, M.A., M.I.E.E., has recently introduced the very useful machine shown in Fig. 7. This is a low-geared hand-steered two-wheel-driven accumulator tractor, which is operated by a man walking before or after it. It performs jobs of the same character as the very intelligent horses sometimes seen about railway goods sidings, but more quickly, controllably, and with immensely more pulling power when required.
A high-speed series-wound motor transmits its torque through a spur and worm two-stage reduction to the rubber-tyred wheels, on the axles of which the machine is more or less balanced fore and aft. An accumulator of 40 cells 64 a.h. normal rating is housed in the " body " and assists in giving adhesion weight. The machine weighs 33 cwt., gives a normal pull of 550 lb., a maximum of nearly 3,000 lb., and can do an eight-hour-day's ordinary pushing or pulling work on one battery charge. The "tractor barrow" will pull as much as 100 tons of trucks on rails and is fitted with a cable winch to give it the flexibility of a mobile capstan ; it can also carry loads up to 15 cwt.
on its own back. I.
Control is carried out by a small hand-wheel, adjacent to which is a small lever, for applying a powerful brake acting on a drum on the high-speed armature shaft. A pole alongside the control wheel enables the operator to steer the machine. Small castor wheels at the four corners of the body can be lowered for use when the machine is used as a winch, allowing it to haul itself when necessary. This "electric mule" is also made in a larger size, giving pulls of 1,000 lb. normal and 4,000 lb. maximum. No one who has seen it in action could gainsay its important scope.
We are indebted to America for many excellent innovations in mechanism, and vice-versa. The electric truck comes within such a category. British engineers have not been slow to make a good showing in this field, and in particular the names of Ransomes, Sims and 040 Jefferies and Greenwood and Batley—both concerns of world-wide reputation—have produced models which, in design and workmanship could not be excelled.
Illustrations 8, 9, 10 and 11 show three models of British-built industrial truck, which give a clear idea of the versatility of this class of works transport machine. The G. and B. half-tonner (sold by W. Goodyear and Sons, Ltd., of Dudley) is designed specially for 'tight corner" work with light loads. Its turning radius is only 5 ft. 2 ins., its length 5 ft., and its width 2 ft. 6 ins. It can, therefore, be taken from floor to floor in factories where space must be gained by building upwards and can be dealt with by a light and small lift quite safely. The two views of the G. and B. elevating platform truck speak for themselves as an index of careful and robust design, as also applies to the tiering truck (Fig. 8) made by Ransomes. The writer's object in these notes has been to show that we have in being an active, progressive electric vehicle industry in Great Britain engaged in developing every sane application of 'accumulator transport along sound engineering lines.