26 March 1999

Check weights on move

By Peter Hill

A TRACTOR-MOUNTED weighing system, based on a top-link with built-in load cell, is designed to perform a host of weight recording tasks, from weighing fruit and vegetables in pallet boxes to the amount of fertiliser in a spreader.

Developed by agricultural weighbridge specialist H&D Engineering, the Parkerfarm Topweigh functions as a conventional adjustable top link, except that the built-in load cell enables the weight of implements and loads carried on the three-point hitch to be displayed on the in-cab monitor.

A position indicator on the monitor ensures that weight recordings are taken with the lift linkage in the same position as when the instrument is calibrated.

"That was the break-through in getting it to work," says H&Ds Mark Spikings, who came up with the idea for the device. "Because of the weight transfer effect and geometry of three-point linkage, you get different readings at different heights, and these can vary by as much as 400kg with a 2t load. But as long as the instrument is calibrated and then used with the hitch at the same height, the system is very accurate."

Other systems use a linkage-mounted "A" frame and up to three load cells with electronics that average the readings. That makes them more versatile, but also more expensive.

The Topweigh is going on sale for £950, and has an "electronic spirit level" which sends signals to indicator lights on the in-cab monitor. These show the operator when the implement is at the calibrated height for an accurate reading to be taken.

The calibration procedure involves adding a known weight to the implement – a 0.5t bag of fertiliser to a spreader, for example – and entering this figure into the monitor. As long as the top link is not altered, calibration need not be repeated for that implement.

Main component of the Top-weigh is a high-tensile steel cylinder with adjustable couplings screwed into each end to suit any category linkage. Design capacity is 10t.

The devices simplicity and versatility make it suitable for a number of applications on farms, says Brian Parker of direct sales agent Parker Weighing Systems, War-borough, near Wallingford, Oxon.

"There are many situations where knowing the weight of the commodity being handled would enable farmers to do things with greater accuracy," he says. "Fertiliser spreading, drilling and dispensing forage or any other feeds are good examples; using the Topweigh would take much of the guess-work out of these jobs, and perhaps save costs." &#42