A NEW HALF-TRACK VULCAN LORRY.
If you've noticed an error in this article please click here to report it so we can fix it.
Another British Manufacturing Concern Produces a 2-ton Lorry Equipped with Creeper-track Transmission Interchangeable with Wheel Drive.
THEprogress of the creeper-track vehicle is being generally watched with much interest, although we must say that, in our opinion, there is not much evidence of enterprise on the part of userS in this country, Who should find the type of advantage in the conduct of their transport work serving to enable them to accomplish part of it with greater ease than is affOrded by wheeled machines, and even enabling them to undertake work for which the wheeled machine is quite unsuited. On the Score of reliability, ecOnconical running and utility,' they need have no fear for the creeper-track. It is now well beyond the experimental stage, and long ago entered the category of practical propositions. In military work, which requires that at least a section—and a very large one—of the transport shall be able to traverse broken ground and be independent of hard roads, the creeper-track will have a very useful sphere, whilst overseas in new countries it will definitely replace branch railway lines or render . new
Ii nes unnecessary wherever the population is so sparse as not to justify the construction of a main line. The latest creeper-track production has been carried out by the Vulcan Motor and Engineering Co., Ltd., of Southport, and th, other day the first completed chassis, eqUipped with a 22.4 h.p. engine transmitting its power through a Ruadless Traction Co.'s unit, was to be seen careering over the sandhills close to the Birkdale shore in Lancashire. It plunged at an acute angle into a deep cavity,. climbed out with apparent ease at the other side, was driven along the top of a high ridge and down a sharp declivity, and then, at a rapid pace, negotiated a region of sand-dunes that set the axles at almost every conceivable Angle to each other.
The lorry has been entirely produced by the Vulcan Co„ the creeper-track unit having been manufacttired under
licence for the Roadless Traction Co:, Ltd. It is designed to carry a 2-ton load, and is equipped with a towing bar for the hauling of trailers.
The engine is four-cylindered, 05 ono. in the bore and 130 mm. in the stroke. The crankshaft is hollow, oil being forced to the journal and connecting bearings by means of an efficient-get* pump. This is a very important point, because a vehicle of this character, being intended to go over uneven ground, may often be stopped with the engine at a steep angle, a circumstance which would make trough lubrication quite unsuitable, because of the troughs at the higher level being drained of their supply of oil.
Another important feature of the engine is the double-thrust washer which is arranged at the front end of the crankshaft to take end thrust.
A radiator of the gilled-tube type with tanks of large capacity, the water being circulated by pump, provides for efficient cooling.
The power is taken through a Ferodo-faced cone clutch fitted with adjustable springs, and between the clutch and the gearbox is a flexible-disc universal joint.
. The gearbox, which has central gate change, gives four forward speeds, the final ratios between engine and driving wheels being as follow :—Top speed, 10.2 to 1; third speed, 15.9 to 1; second speed, 26.3 to 1; first speed, 69 to 1; whilst the reverse gear has a ratio of 115 to 1. It will be seen that very low gearing is provided on first speed and on reverse.
Power is transmitted through an open tubular propeller shaft, fitted with a cross-pin type of universal joint, efficiently lubricated, to an overhead worm and wheel, which transmit the tithe through high-tensile steel shafts to the driving sprocket wheels, which run on removable bronze floating bushes.
The spring seats and bogie brackets of the rear axle are carried on bestquality drawn-steel tube. The two fourwheel rubber-tyred bogies run on the inside of the endless tracks, and are fixed to the bogie brackets by largediameter spherical joints, so that universal motion is amply provided for. At the forward end of the bogie frame, on each side, is carried the idler wheel on an arm which Is adjustable, so that the stretch in the chain track can, when necessary, be taken up. The idler wheeli are faced with rubber tyres so as to ensure quiet running of the endless track.
This latter, by the way, consists of stamped-steel links having automatically lubricated spherical joints, designed to permit cornering without drag on the road surface, it being possible for a radius of 17 ft. to be easily struck.
The large driving wheels at the back have sprockets engaging with the teeth on the inner side of the endless tracks. All the weight is carried by the four small wheels on each aide, the driving sprocket and the idler not carrying any weight at all.
The frame is constructed of pressed. sheet nickel-steel, and has very substantial cross-members, whilst it is sup-. Ported by semi-elliptic springs at the front and rear, ample strength being provided in these components.
There are two independent braking systems, a pedal operating largediameter contracting-type shoes on drums mounted behind the gearbox, whilst the side lever operates through compensating-gear, expanding shoes which act on drums 18 ins, in diameter attached to the rear wheels.
The front wheels are keel discs, arranged to take 34-iu, by 7-in, straightsided pneumatic tyres.
The front axle is of heavy I-section 40-ton steel forged in one piece.; in fact, it may be said that throughout the vehicle there is ample strength.
The steering is accomplished through wheel and worm and complete bronze wheel, the latter allowing four positions and being enclosed and working in oil.
The petrol tank is carried on the dash, thus ensuring gravity feed to the carburetter whatever may be the attitude of the vehicle, and it has a capacity of no less than 22 gallons.
The following are a few essential dimensions :—Overall length, 19 ft. 21 ins.; overall width, 6 ft. 51 ins.; wheelbase, 9 ft. 71 ins.; wheel track, 4 ft. 111 ins.; length of loading platform behind driver's seat, 10 ft. 8 ins.; whilst its weights, unladen, are as follow :—Front axle, 17 cwt.; rear axle, 44i cwt., the total unladen weight, therefore, being 3 tons 1 cwt.
It is claimed for the chassis that it can carry a net load of 2 tons, or, in addition to a 2-ton net load, can haul a 2-ton trailer and can climb with such load a gradient of 1 in 4.
This train and load can, it is claimed, be largely augmented if desired by a very small increase in engine power, whilst the new models will be fittedwith a quick-change attachment, enabling the vehicles to be operated with ordinary road wheels.