Remote control for Swedish loaders
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• A Scania normal-control LS 140 6x2, specially fitted as a logging vehicle, is in the UK this week to demonstrate a new Swedish-developed control system for lorry loaders and similar hydraulic equipment.
The system using operator-carried remote controls is the result of a project carried out by the Computer and Electronics Division of Saab-Scania (DATASAAB) in collaboration with Monsun-Tison, leading Swedish makers of mobile hydraulics.
The use of electro-hydraulics in a portable two-lever, multi-function, control console allows the operator of a vehicle-mounted crane free movement within the handling area. He can check the load from all sides while actually lifting, he can position himself, for his own safety, outside the radius of the swinging jib.
The system, using only two manipulators to transmit signals to the servo-valves on the crane, also allows more accurate control of the various directional functions and to apply braking forces more gently.
In the Monsun-Tison-DATASAAB system the loader functions are exemplified by their smooth continuous movements with proportionate response to finger-tip pressure on the control levers.
Operator-safety requirements are being tightened in many countries: in West Germany recently the Industrial Safety Board drafted legislation which, in effect, will severely restrict conventional operating methods of vehicle-mounted equipment, thus making remote control a necessity.
The vehicle being shown in the UK — Monsun-Tison is represented here by ASH Components Ltd, of Ossett, Yorks — is fitted with a Jonsered knuckle boom loader with a reach of seven metres. The Monsun-Tison-DATASAAB portable manipulator — carried by an operator's belt
is connected to the crane by a 12mlong wander lead. The operator can thus place himself in the most suitable position to perform the loading and unloading work. The vehicle's 24V supply is used for the electric control circuits while the main hydraulic system has a pto-driven twopump lay-out for optimum performance.
Another unusual feature of the demonstration unit is the trailing axle drive used for extra traction when extracting timber over unmade roads. Made by AB Zetterbcrg, of Ostervala, the Robson-Drive consists of a "paddle wheel" brought into contact with the tyres of the driven and trailing axle by means of a power-operated ram.