29 September 2000

VARIABLE-WIDTH UNIT

SORTS THE MUCK OUT

This mighty variable-width scraper just missed

out on the prizes in last years

farmers weekly/Barclays Bank inventions

competition. Andrew Pearce travels

to Cheshire to see how it works

THE icy blast of winter can be a keen spur to a mans thought processes. As Alan Winstanley scraped out cattle yards with a doorless Ford 4000, the many attractions of a cosy materials handler cab set him scheming – especially as several of the five passageways at Highfields Farm, Audlem, Cheshire, needed two chilly passes to clear.

But he couldnt just adapt his existing scraper to fit the farms Sanderson TL6. It wouldnt put up with the work, let alone the boom downforce he had in mind for shifting dry muck. Which left only one solution – build something that could. And while he was at it, add width adjustability so all passageways could be scraped in a single pass. The result, conjured up last autumn for around £700, is a unit built like a brick convenience and hydraulically variable from 2.1m (7ft) to 4.2m (14ft).

&#42 Three-part harmony

Highfields Farms 132ha (325 acres) are set in Englands prime milk producing belt. With 180 cows plus followers, theres plenty of muck to shift. Mr Winstanleys long-standing machinery interest may be unusual for a dairyman but over time its certainly produced the goods, including a neat set of self-steering flat rolls. As with most other farmer-inventors, he laid no formal plans for the scraper, working instead from a mental layout and sorting details as he went.

The unit is in three parts – a floating headstock, the width-adjusting system and the scraping rubber. The headstock mimics a tractors three-point linkage, picking up on the Sanderson carriage and locking into place hydraulically. Its upper section is braced to take boom downforce and carries pivots so the scraping section can follow contours, with short check chains limiting travel and allowing lifting. Lower down, heavy duty bushed pivots based on trailer drawbar rings let the rubber flip over for reverse operation – though Mr Winstanley prefers to work the unit forwards.

The rubber itself came from a specialist company in nearby Sandbach. Costing £250 and measuring 5m long x 380mm deep x 50mm wide (16ft 4in x 15in x 2in), the limited maximum lengths available forced Mr Winstanley into linking two strips at the rear by sandwich plates. "I was worried that the central joint might leave a stripe, but it doesnt," he says.

A potential headache was devising pivots for the scraper wings, as these would need to move in an arc as the wings opened. But potential pain evaporated when Mr Winstanley spotted that the rubber itself was strong enough and stiff from its own pivots, letting him simply clamp the wing sections between sandwich plates and attach these directly to the central width-adjusting system.

&#42 Clever thinking

This set-up shows clever thinking. A length of 180mm x 180mm (7in x 7in) box set horizontally forms the main member, with two smaller wing-controlling sections telescoping out from it. Early on, Mr Winstanley realised that it wouldnt do to use a pair of same-diameter rams to slide the wing sections in and out: if he did, then different ground resistances would often make one side open before the other and the whole wing assembly could "lozenge" sideways if one wing squeezed into a passage wall. So he took some advice and settled on the arrangement shown in Fig 1.

Double-acting rams of different sizes are used. Diameters are calculated so that the surface area and volume on the rod side of ram (1) is as close as possible to the area/volume on the face side of ram (2). These chambers (A) are then piped together in a closed circuit. Oil from the Sanderson arriving in chamber (B) pushes ram 1s piston towards the scrapers centreline, closing one wing and simultaneously moving ram 2s piston a similar distance to close the other wing. Reversing flow sends oil to chamber (C), opening the scraper. When the Sandersons spool is closed, oil is locked in the supply circuit so the wings cant "lozenge" when one side touches a wall.

Building took around £700 in materials and plenty of Mr Winstanleys spare time. Finished before the cows came in, the scraper has weathered a winters graft with little wear showing on its reversible rubber. "I like to build things strong, and so far have never had the welder on it," he smiles. "By varying width on the move I can scrape all our different passages, and by weighing down with the boom it scrapes everything clean on drying days."

Alan Winstanleys scraper clears passageways from 2.1m to 4.2m in a single pass, accepting boom downforce as necessary to shift dry muck.

One of the great things about farmer-inventors is that they can be bold and uncompromising in a way thats often difficult for companies that have to keep accountants and shareholders happy.

The variable-width

muck-spreader featured this month is a good

example of what can be achieved through a

combination of necessity and single-mindedness.

Its built like the proverbial brick convenience and does its job with

efficiency and aplomb.

Were also celebrating other old-fashioned-sounding values this month.

A stack of 1960s issues

of Farm Mechanisation

(the precursor to Power Farming) recently came into our possession and a flick through their dusty pages revealed a real insight into the machinery of the time.

So weve picked out a selection of machines that were then ahead of their time or seemed to offer a useful avenue to future gains in productivity or

efficiency. Of course, some are still with us today, while others disappeared without trace.

One way or another, its a chance to hark back to a gentler agricultural age, when mobile phones,

Spice Girls and IACS forms werent even a twinkle in their inventors eyes.

Fig 1: Working width is controlled by different-size rams (1 and 2). Diameters are set such that chambers (A) have the same volumes and piston areas. Oil coming into chamber (B) shunts trapped fluid between chambers (A), forcing both rams pistons inwards and closing the scraper wings,

while oil in (C) free-returns to the reservoir. Reversing supply flow reverses the process, increasing working width.

Above: Scraping starts with wings pushed out to suit passage width…

Right: …As the scraper leaves the passage, a touch on the Sandersons spool lever opens wings to full width…

Below: …Then with muck pushed over the slats, the wings are folded back to 2.1m while the Sanderson travels to the next passage.

Above: Solid build lets Alan Winstanleys unit handle plenty of downforce.

Below:Sliding box sections and rams look after width adjustment, with reversible rubber forming its own pivots. Lower pins are modified trailer drawbars, letting rubber swing over. Steel strip on inner sliding box takes up clearance.

Above: A full 4.2m, confirms Alan Winstanleys tape. Flexible tips allow intimate contact with walls and act as shock-absorbing buffers in case of overshoot. Two separate rubber lengths join at centreline.

Left: Strong headstock carries wide bottom pivots and check chains so rubber and width-adjusting sections can float. All pivots are bushed and greaseable.