Built-in check on laden weights
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by Ashley Taylor
• Demonstrations are now taking place of a rapidly operated device that provides a clear indication of exact axle loadings at any time. Cost of fitting is expected to range from about £125, according to size of vehicle.
This equipment, designed by Mr. P. Hanson, a director of Comberhill (Yorkshire) Garages Ltd., Ings Road, Wakefield, Yorkshire, is at present still in the prototype stage but it is expected that manufacturing arrangements will soon be concluded. The unit is applicable to the full range of vehicles from light tippers up to maximum capacity artics.
A dial is incorporated in the dashboard and in order to obtain a reading showing the total weight of the load it is only necessary for the driver to engage a lever in the cab which operates a hydraulic circuit. A multiple dial panel can be employed to indicate separate axle loadings or, instead of the dial, coloured warning lights can be used to show that a pre-determined figure has been exceeded. The reading comes up within seconds of the lever being actuated.
Since the system is hydraulically operated it is necessary for a power take-off to be introduced if not already available on the vehicle. The main circuit feeds pairs of small hydraulic rams attached to the frame, these operating in contact with hydrostatic sensing pads, a pair of which are mounted on each axle. Bringing the hydraulic system into action by operating the control actuates the rams which bear down an the pads this resulting in the loading being carried on the pads, which in turn, cause the dials in the cab to register the payload weight carried by each axle. The whole movement occupies perhaps 30sec, so that in the case of dispute regarding the weight distribution of, say, containers the driver can check with negligible delay whether he is complying with the regulations. Equally, in the case of hopper loading or intermediate deliveries and collections the minimum time is occupied in deciding the position.
Operation of the actual rams has the effect of transferring the weight from the springs to the sensing pads which are linked by their own sealed circuit to the gauge. The jacks as fitted to the prototype are of 6in.-stroke, so arranged that they are fully extended before there is fear of them pulling against the springs.
To ensure that rebound spring reaction does not affect precise weights being registered it is advised that either a double rear shackle or a slipper rear end should be fitted. For use with semi-trailers the sealed circuit would be provided with flexible pipes and a detachable gauge.