A James and Browne Five-ton Model.
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The Latest Designs by this Maker are Characterized by Simplicity and Compactness : the Comfort of the Driver is also Considered.
In our last issue, we were enabled to publish a description of the principal characteristics of the new " electric-trolley motorbus." It will be remembered that, on that occasion, we drew attention to the fact that the whole of the undercarriage had been designed and manufactured to suit the requirements of the Railless Electric Traction Co., Ltd., by James and Browne, Ltd., at its Westeroft works, Ring Street, Hammersmith, W. We have, since the publication of the above article, been afforded an opportunity to secure particulars of a new type of heavy commercial-motor vehicle, of which this maker has recently despatched the first example to Canada.
The "Trolleybus" Chassis.
As many of the parts embodied in the chassis of the demonstration " trolleybus " had previously been standardised on the new-nee-lel petrolpropelled machine, we make no apologies for reproducing, at the foot of the next page, a plan drawing of the complete " trolleybus " chassis. From this, it will be seen that the special form of gearbox is situated midway on the chassis frame, and that the two tramway motors are placed one on each side of the box. As we mentioned last week, this gearbox contains two separate bevel drives, one for each of the motors, and no connection between the two is normally provided ; the two cross-shafts are, however, in line and are so arranged that, in the event of failure of one motor, they can be coupled so that the drive is transmitted equally to the two chaindriven road wheels. The deep fitch plates, whirl form practically the whole of the bottom sides of the body work, and which are built on to the
outside of the channel frame, can be seen in position in the illustration at the foot of page 114.
A Short Wheelbase.
The new machine, of which we reproduce two photographs, is modelled largely on the lines of this maker's earlier three-ton model, with which a considerable measure of success has been achieved. The present example
is primarily intended for loads up to five tens, but three-ton and two-ton adaptations of the same scheme are in hand. The Jamee and Browne designers have, in this, their latest production, kept before them the necessity of securing great simplicity and accessibility for the service in view. In order that these vehicles should he capable of easy manoeuvring in confined spaces, special arrangements have been made to secure a. short wheelbase and large turning lock. As will be seen from the photographs to which we have already referred, the engine, as in previous models, is placed well forward over the front axle, the position of the driver being at the side of this unit. What is known as a "tram " front, which is hinged to the end of the chassis frame, gives a distinctive and comfortable appearance to the whole design. Efforts have been made by other makers to secure compactness of arrangement by the seating of the driver in a similar forward position, but in only one or two cases has the driver been satisfactorily placed at, the side of the engine; the more usual practice is to build a control platform over the top of this part of the mechanism. The latest James and Browne disposition, however, has resuited in the arrangement of convenient and, withal, comfortable beating accommodation for the driver, and the provision of the maximum platform space on a moderate wheelbase without undne overhang. It is claimed that this arrangement saves no less than 2 ft. in total length of wheelbase—a factor which should constitute a valuable selling point in certain circumstances.
A New Engine.
The new engine is a modified edition of the James and Browne standard practice, such as that which has always been known as the " J. and B." Vertex. The five-ton machine is equipped with a four-cylinder "5 by 5" engine, which gives -15 h.p. at LOGO r.P.m. Overhead inlet valves have now been fitted, and this has resulted in the reduction of the overall width of the engine, and has, therefore, allowed more space to be allotted to the driver. High-tension magneto ignition is provided in place of the low-tension system with which the earlier models ran so satisfactorily.
In this connection, the writer has noticed that, although many users and makers profess to a lingering affection for the reliability of the low tension system, they are inclined to come into line, with a high-tension magneto, largely on the score that its use is now becoming more customary. If it were not for this question of fashion, it is reasonable to suppose that many makers would he loath to forsake a system from which they have had very reliable results in the past.
An Accessible Clutch.
A special form of control has been devised, in which the throttle is operated by means of a foot-pedal. This latter, which controls the governor, renders it impossible for the Clutch to be removed when the throttle is fully open; the driver has to use the same foot for the throttle and the clutch pedals.
We illustrate, by reproductions of drawings, the special forms of clutch and of spring drive which are characteristic features of this maker's machines. It will he noticed that, with regard to the former detail, a large leather-faced cone clutch has been embodied, and this in preference to any of the more-modern forms of plate clutch for commercial-vehicle purposes. An examination of the drawing shows that the clutch is controlled by three strong helical springs mounted on pillars which are carried by a large-diameter flange. This arrangement has been adopted in order to obviate the necessity of employing the more-usual central spring, which is often very inaccessible. The clutch spindle is mounted on large hall bearings. and the male member of the clutch is withdrawn, by means of the isual grooved collar, through cotters, which protrude through a slot in the main shaft. The outer ball race is held by a form of spider cage, which is bolted to the edge of the flywheel.
An Efficient Spring Drive.
The form adopted for the spring drive is clearly shown in one of the drawings to which we have already referred. Cast-steel arms bear, on
their extremities, spherical sockets, which carry adjustable spindles, and these, by means of strong squaresection helical springs, serve to keep the arms apart at a definite distance until such time as shrieks, through unreasonable use of the clutch sir brakes, are to be transmitted through the driving gear.
All the different models of chassis are fitted with four speeds forward and one reverse, the top speed being direct drive; the five-ton chassis has a gearbox which gives speed-ratios of 3, 51, 91 and 13i m.p.h. on the road, The differential gearbox is separated from the change-speed box by double universal joints, and is constructed in exactly the same manner as is customary with modern designs of live hack axles. The silent type of chain is fitted for the final drive to the 40 in. hind road-wheels. The general appearance of the other details may be well ascertained from the photographs of the complete machine. The tare weight of this model is well under three tons.