Expanding Variety in
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TRAILER DESIGN
Modern Bogie Arrangements, Low-pressure Tyres, Cranked Frames and Improved Brake Gear Allow for Compliance with Axle-weight Regulations, Permitting Higher Road Speeds, Cross-country Work and the Conveyance of
Difficult Loads
APART from the familiar types of trailer, including the four-wheeled turntable kind, the two-wheeled semi-trailer, and extensible twowheeled and four-wheeled pole-type trailers, some new ideas in trailer design which have developed in the past year or two are extremely interesting to those whose haulage tasks are best suited by trailers. The names of Eagle, Dyson, Carrimore, Cranes, Scamme11 Lorries, B r o a house, Taskers, Scammell and Nephew, Harrow, in England, and Industrial and Universal, in Ireland, are familiar, and many of
them have produced egregious types.
Probably the latest important development is that in connection with bogie arrangements, introduced, in many instances, so as to distribute the load in accordance with regulations. Quite an innovation is the type incorporated in the Scammell articulated .eight-wheeler for 17-ton loads., of whi4li a full report appeared in The Commercial. Motor dated May 5th, whilst a bogie-type pipe-carrying semi-trailer was dealt with in our issue for April 28th, both machines having 13.5-in. by 20-in. Goodyear low-pressure tyres and both being products of Seammell Lorries, Ltd., Watford.
The Eagle Engineering Co., Ltd., Warwick, recently produced a fourwheeled bogie-type detachable semitrailer for carrying bottled milk in crates. This particularly interesting 6-tonner is shown in an accompanying illustration, and it will be seen that it allows of a useful super-imposition of load upon the tractor driving axle.
The same company has employed the bogie principle for the suspension of a 1-.10-ton trailer, this having four rockingbeam bogies, each comprising two double-tyred wheels in tandem, which means that each of the 16 solid tyres carries about 4 tons.
As an example of the use of a fourwheeled trailer to form part of an articulated vehicle, a machine, produced by R. A. Dyson and Co., Ltd., Grafton Street, Liverpool, to the order of Pickfords, Ltd., is worth mentioning. The machine has a deeply cranked frame, and may be detached from the motive unit, a Dyson forecarriage being fitted to make it suitable for ordinary duty as a four-wheeler.
The advantages of single-axle suspension for a trailer are sometimes made use of evhen big and heavy loads have to be carried. For example, an Eagle pole-tYpe two-wheeler, in conjunction with an industrial tractor; is used far conveying bY road con:inlet& railway-carriage bodies. Whilst the use.. of the same class of trailing unit with, of course, an extensible pole; in con
junction with a powerful four-wheeldrive chassis has been found most efficacious for handling on rough ground felled trees, pipe lengths, etc.
Even the apparently ordinary four-wheeled trailer of to-day is so differently equipped from earlier types as to give a far better performance in every way. Chassis are produced which withstand most severe usage. An excellent example is that of a timber-carrying extensible four-wheeled trailer produced by Cranes (Dereham), Ltd., Dereham, Norfolk. This machine, which was dealt with in our issue for last week, has orthodox turntable steering but, by reason of its double pneuatic tyres, it is able to negotiate soft ground when carrying extremely heavy tree trunks, whilst the design of, the bOx-sectioned pole, bolsters and suspension _system is such as to accommodate articulation, to withstand severe stresses, and yet to minimize the weight and rolling resistance.
The Eagle overseas type of fourwheeled trailer, which r has a turntable incorporating a spring-loaded king-pin so as to give easy riding over rough ground and to prevent distortion to the trailer frame, i.e also in this class.
The overseas' model produced by .T. Brockhouee end Ga., Ltd., of Victoria Works, .West Bromwich, has reinforced boleter, bars, so, arranged that the bolts securing the holster blocks are, free from sLear stresses, whilst cone-shaped blocks automatically take up weir and re,lieve the king-pin of draught ,stresses. This machine has a frame of the fullwidthe type to obviate the need for crossbearers, thus reducing the floor height.
Carrimore Six Wheelers, Ltd., is renowned foe the reliability of its trailers, every, conceivable kind being made at its works On the Great North Road, Landon, N.12. A useful outfit for transporting a 15-ton steam navvy figures in an accompanying illustration; to obtain a low platform and reduce the rise of the ramps employed for loading and unloading, four small rear wheels, on two short axles, are fitted, the frame being deeply arched to per
Mit larger wheels 'with 24-in. brake drums to be used at the front. This concern also employs a most neat selfcentring cone-type engagement for the hydraulic king-pin of its semi-trailers. Taskers of Andover. Ltd., at Waterloo Ironworks, Andover, produces all types of heavy trailer, tjae forecarriage being -generally of the Ilind having a locking ring of flat mild steel which engages with, a channel-steel locking ring fixed to the main frame. It has semi-spherical centre castings, which relieve the king-pin of shearing stress.
Good reinforcement of trailer framework to resist the loads dealt with when tipping gears are fitted is exemplified by an accompanying illustration of a trailer produced by G. Scammell and Nephew, Ltd., Fashion Street, London,
E.1. Whilst there are no propellershaft complications, the fitting of tipping gear. .:to trailers calls for sturdy erese-membering to distribute the load and when power operation is required the power transmission from the motive 1:n1ft calls for careful design. The Eagle Engineering Co.' Ltd., has had a lot of experience with this .problem, its hydraulic tipping gear with self-sealing detachable coupling to the pump on the
tractor being a highly reliable fitting.
The Harrow Industrial Co., Ltd., Stanley Road, S. Harrow, Middlesex, specializes in electrically welded trailer frames of -great strength.
When it comes to lighter types of trailer which, nevertheless, are expected to travel over rough ground, the design of the De Rouet Trailer Co., Ltd., I, The Causeway, Staines, deserves consideration. In this case a two-wheeled trailer is equipped with a rigid drawbar extending to the rear of its frame, and the drawbar is allowed fore-and-aft movement, as well as oscillation in the vertical plane against springs, Superimposition of part of the load
can be effected even with a four-wheeled type of trailer, a fascinating method of obtaining this requirement. being that employed onBeardmore outfits, marketed by William Beardmore and Co., Ltd., Park Crescent, London, S.W. to the design of the turntable, the front wheels may actually be lifted from the ground. For normal use in conjunction with the Beardmore tractor, however, it is usually necessary to transfer only sufficient load to give the necessary adhesion for the driving wheels of the motive unit, a screw pillar being employed for raising the drawbar and being located some inches in front of the driving axle, so that snaking of the trailer is eliminated. Trailers having Ackerman steering in place of the ordinary turntable forecarriage are, of course, made by such concerns as Carrimore Six Wheelers, Ltd:, whilst one produced by the Kingston Engineering Co., of Danson Lane, Hull, will be described in a subsequent issue. Low-pressure tyres are being tried out by many trailer makers, Industrial Vehicles (Ireland), Ltd., Athy, Co. Kildare, Ireland, being a concern which is experimenting in this direction.