A NEW ACKERMAN-STEERED TRAILER.
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Details of the New Welding Trailer Designed Essentially for Moderately Fast, Heavy Haulage.
THE first points which strike the 1 observer when examining the 5-ton trailer which has recently been designed and built by the New Welding Co., of 26, Ilosebery Avenue, London, E.C.1, are its strength and the neat way in which the frame construction is carried oat. The whole of the exterior portion of the frame is built from two rolledsteel channel members bent at their ends, so that joins are at two corners diagonally opposite. To make these bends, a V is cut out of each web, but here, and at the joins, electric arewelding is resorted to as is the case with the cross-members, spring brackets and other important parts, and as few concerns have had more experience in welding than this company it is only to be expected that a good job has been made of it.
There are three cross-members, and these are welded right into the channels, whilst the drawbar pulls on a fourth member which takes the form of an inverted channel welded below the side members.
The drawbar is provided at its front end with a long coil compression spring to reduce starting shocks. It is divided, end the forward portion is connected to the rear portion by a fork-and-pin joint, so arranged that the front portion can be lifted or lowered in relation to the rear portion, but there is no flexibility in the sideway direction.
The forward end of the rear portion of the drawbar rests in a guide plate, also welded to the frame, whilst on the rear portion of the drawbar is a slide with a downwardly projecting pin connected by two arms to the cross steering connecting rod, which is, in turn, provided with sockets for the ball at the end of each steering :um on the front-wheel stub axles.
Send-elliptic springs are employed for both front and back axle. The front axle itself is an I-beam forging with forked ends, whilst the rear axle is a particularly interesting type, being built up with a central tube into which end tubes are forced under a pressure of 80 tons. These end tubes form the wheel journals and they also pass through the spring anchorages which carry the brake-shoe fulcrum pins. Phosphorbronze floating bushes are supplied for all the wheels and, in the case of the rear axle, these are lubricated from the axle centre, where is provided a special oiler. Phosphor-bronze rings are utilized to take the side pressure of the wheels.
The cross members are so arranged that the spring brackets are in line with them, and underneath extensions of the brackets are actually welded to the Cross-rnembere.
The rear wheels have Y-shaped spokes of cruciform i section and the front
wheels straight spokes of the same section.
The brakes are of the internalexpanding type operated by a lever at the front of the trailer, provision also being made for opetating this brake from the towing vehicle or tractor. Between the lever and the rest of the brakeoperating gear there is a rod with a right and left-hand-threaded adjuster.
In the past a certain amount of trouble has been experienced with trailers equipped with steering on the Ackerman principle, owing to the inclination of some of them to develop an action known as " snaking." In some designs it would mincer that this trouble has been successfully obviated, and we are assured by the maker that tests with this new trailer have shown it to be entirely free from this disconcerting action even when running at high speeds on rough roads.
The main dimensions of the trailer are as follow :—Frame, 13 ft, long, 3 ft. 64 ins,. wide; track (front), 6 ft. 2i ins.' (rear) 6 ft. 41ins. ; wheelbase, 7 ft. ,I ins. It is interesting to note that twin tyres are used on the rear wheels, and singles on the front.