Transatorque equals 25-man trailer shove
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• To provide a means of improving the traction of articulated vehicles, Neville Truck Equipment Ltd has developed a sys tem of driving the wheels of a semi-trailer. Known as the Transatorque, the equipment is intended for use on any tractor-trailer combination which is called on from time to time to negotiate difficult going.
At the heart of the Transatorque system are two 9.5 hp Edbro HMA2 hydraulic motors, each one forming part of a drive assembly mounted immediately ahead of one trailer wheel. Through a 7.5 to 1 reduction gearbox the motor drives an 8in.dia 6in.-wide roller which takes the form of a "treadmill cage". The open construction of the roller prevents'intid becoming clogged between the bars. The 0.44in.-wide cross bars of the cage engage with the tread of the inner tyre on a normal twin-wheel installation.
Each motor and roller assembly is pivoted horizontally on bracket flanges forming part of a fabricated outrigger ahead of the wheel.
A type 16 single diaphragm air chamber installed on the outrigger acts through an arrangement of bell-crank levers to bring the roller into contact with the tyre tread when required. Normally the roller is spring loaded about 1.5in. -away from the tyre.
A heavy-duty nine-cylinder Edbro pump is pto mounted on to the tractor unit gear box and supplied from a 15 gall hydraulic reservoir behind the cab. It delivers fluid at about 1500 psi through flexible high pressure hoses and swivelling couplings on the trailer headboard. The feed to the hydraulic motors is carried via a flow equalizer valve mounted below the trailer frame, so that both wheels are positively driven at equal speed—the effect being equivalent to a differential lock.
In the tractor cab a normal pto control regulates the flow of fluid to drive the hydraulic traction motors. .A second lever selects air to the actuators which bring the drive assemblies into effect. Both are on-off controls and not graduated.
In terms of driven speed the trailer wheels match the tractor driving wheels when first gear is engaged—the gear normally selected when a driver is starting from rest. Driver roller torque on each side is 3300 lb-in, so that the total tangential tractive effort on the two trailer wheels is 17601b—equivalent to that exerted by the driving wheels on a typical five-speed tractor when in 3rd or 4th gear.
It has been calculated that the assistance provided by the trailer drive motors is equi
valent to the effort of about 25 men pushing the vehicle.
Neville Truck Equipment's first Transatorque installation has been carried out on a combination hauled by a Bedford KGA tractive unit—one of the non-standard 8ft-wheelbase chassis operated by Bass Charrington Ltd. The Bedford 381 cu.in. engine drives through aTurner T5A five-speed
gearbox. The 17ft. Crane Fruehauf singleaxle platform trailer is rated at eight tons gross trailer weight.
Bass Charrington required added traction on its small artics to enable them to get on and off agricultural show sites where double-drive would normally be necessary.
As fitted to the brewery vehicle each Continuedon page 20