Carrimore Flexible Mounting for Semi-trailers
Page 24
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A N entirely new principle of mount
ing a semi-trailer turntable has recently been adopted by Carrimore 5,x Wheelers, Ltd., Great North Road, London, N.12. Instead of the base of the turntable being rigidly mounted en the tractor chassis, it is now suspended on C springs, the arrangement being clearly shown in one of the accompanying illustrations.
Although the springs are short in the leg, a necessary condition to the maintenance of stability, they provide a surprising degree of flexibility in a vertical plane. Each of the three leaves in each assembly is graded in thickness, and, to provide for free movement when flexing, the leaves are " air-spaced," With this new arrangement, which has given perfectly satisfactory results over a long period, one of the ,bugbears of the rigid-pin system, that of weat, has been overcome, Furthermore, the cushioning effect, both in pulling away and in hraking, greatly reduces load shocks to the chassis of the tractive
nit
Two other interesting features incorporated in the Carrimore trailer, which we inspected, concern the braking s}stern and the method of suspending the mudguards. Regarding the former, the vacuum cylinders are now mounted directly between each pair of wheels, the brakes being applied through a system of short levers. Thus, there is practically no lost motion between the brake pedal and the final means for application, spch as is present when the cylinders are mounted remote from the wheels.
The mechanical hand brake is
operated through a lost-motion device. being thus quite independent of the vacuum system.
A weakness in the past has been the comparatively frail stays which have been responsible for supporting the mudguards, the continual movement and jarring ultimately causing fatigue of the metal and fracture. The Carrimore concern has solved this problem by the use of stout channel members, incorporating a cross-bar at the rear, which forms a convenient means for withdrawing the axle and wheel assembly. Incidentally, the trailerwe examined is of the removable-axle type.
Reverting to the• spring-mounted • turntable, two such springs are used on semi-trailers up to 12 tons loading, and four from 12 tons up to 24 tons, In all cases, the springs are of a standard design in respect of the number of leaves and their dimensions. Each spring is held by four in. high-tensile steel bolts, secured by Simmonds fibretype self-locking nuts.