Cranes Build New 32-wheeled Trailer
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TO meet the special requirements of the Department of Irrigation of South Africa, Cranes (Dereham), Ltd., Dcreham, Norfolk, have built three trailers, each using two 16-wheeled bogies, the wheel assemblies of which embody the Cranes hydraulic suspension system.
The estimated load of the excavators to be carried is 45 tons, and in view of the rough nature of the ground to be traversed, the loading on each row of four wheels has been limited to 8 tons. The 32 wheels therefore provide a safe margin. Similar bogies, if employed in this country, would be used for 90-ton loads.
The bogies will be supplied to the Trailer Manufacturing Co., Ltd., Denver, Johannesburg, who will maim
facture the load-carrying portion to Cranes design.
This will have an effective load area of 14 ft. by 10 ft. 6 in. The turntable runs on a double row of balls on a circle approximately 70 in. in diameter. The load is carried by 11-in.-diameter balls spaced apart by 1-in.-diameter balls. By this means grinding action is eliminated during rotation.
From centre to centre of the turntables the span is 33 ft. and the overall length, not including the drawbar, is 47 ft. 2 in.
Cranes also have in production the F12/01 all-purpose semi-trailer for 10-12-ton loads, with a maximum gross rear-axle loading of 9 tons. The standard chassis length is 24 ft., the overall width, being within 7 ft. 6 in. Pins, shackles and spring eyes are eliminated in the semi-elliptic springs, which are mounted on the Cranes buffer principle. As the chassis is built up by the use of bolts fitting in reamed holes, it can be easily broken down for shipping overseas, and parts can quickly be replaced by unskilled labour.
This semi-trailer is normally fitted with the S.A.E.-S.M.M.T. standard king-pin so that it can operate with any tractor fitted with a fifth wheel that takes this pin. The Cranes automatic fifth wheel, which incorporates a rubber mounting at its centre, is available to suit this standard king-pin.