Three Trailers for Special Duties
Page 43
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THREE more special purpose vehicles—two semi-trailers and a drawbar trailer—have been produced by Carrimore Six-Wheelers, Ltd., North Finchley, London, N.12. The largest is a semi-trailer 50 ft. long and 9 ft 41 in. wide. It has a 14-ton rating and is intended for use with a special insulated body overseas.
With a length of 38 ft. 3 in. in the well, it has four longitudinal members The inner two are constructed from 10-in, by 4-in, channel and braced with trusses built up from 4-in, by 3-in. by 4-in, angle steel. The outer two members are of 7-in. by 3-in. channel. Lateral rigidity is ensured by ii main cross-members.
Tandem rear axles are used, these being carried on two semi-elliptic springs pivoted at their centres and having rubber-bushed eyes. Braking torque is controlled by rubber-bushed radius arms, which, being diagonally disposed, also perform the duties of Panhard rods.
Composite Pivots
In the interests of longevity the spring centre pivots comprise Meehanite bushes clamped endwise on the pivot spindles and running in lead bronze bushes in the hanger brackets. Two-pipeline airpressure operation is employed for the 154-in. • by 44-in, two-leading-shoe brakes, a reservoir and breakaway valve being incorporated in the circuit.
Four levelling jacks with two-speed gears are fitted, two at the front and two at the rear. There are two tinderslung spare-wheel carriers at the forward end of the semi-trailer well.
An S.A.E.-type king-pin is used for the coupling, and the twin rear wheels carry 9.00-20 (12-ply) tyres.
A second semi-trailer, rated at 25 tons, is 10 ft. wide and 17 ft. long in the well. The 2-in.-thick timber floor is carried on four longitudinal members, the inner two of which are 12-in. by 8-in. joists, whilst the outer. members are constructed from 7-in. by 3-in, channel steel. Loading ramps for use at the rear are stowed on brackets at the front: The rear bogie is composed of two balance beams, each carrying two short stub-axles with twin wheels and 8.25-15 (t4-p1y) tyres on each side of the balance beam. The 124-in. by 34-in. two-leadingshoe brakes, fitted to all wheels, arc operated by air pressure through four cylinders, one to each axle, and two pipelines. The hand-operated Oarking brake works on the rear line of axles An S.A.E.-type king-pin and landing gear with simultaneous operation for both units are provided. Bollards on the front cross-member can be used when winching equipment on to the semi-trailer.
The third machine is a six-wheeled trailer for the carriage of special equiptnent connected with the movement of radio-active materials. With an overall length of 22 ft. and a maximum width over the tyres of 7 ft, 10 in., the trailer has trunnions ahead of the rear bogie, in which the load is secured while resting on a detachable bolster at the forward end of the trailer. Load capacity is 20 tons and the wheelbase 13 ft. I in.
Vacuum Brakes
Vacuum braking is employed, two vacuum cylinders operating through independent cross-shafts and compensator linkage to each pair of wheels on • the rear bogie. The hand-operated parking brake works on the same crossshafts through an additional compensator and linkage.
Short overhanging stub-axles mounted. on balance beams pivoted on the ends of a cross-member, which is 5 in: square, carry the rear wheels. Single 20 by 9-in, solid tyres are used on all wheels.
The fore-carriage is supported On a steep-angled tapered-roller bearing and is secured to the turntable by pins and bushes that allow it to pivot laterally. The steering can be locked when the trailer is being towed in a reverse direction.