more stability
Hedge-cutter designed for
more stability
Smithfield saw the unveiling
of a new generation of
hedgecutter/vergers from
Twose. Ian Marshall took
a top-of-the-range 580S out
into the hedgerows
FARMER and contractor demand for more reach from their hedgecutters to match their high horsepower tractors has given designers a headache, insists Twose managing director Richard Burman.
It is the age-old problem of how to combine reach with stability.
Twoses answer to this poser lies in the design of its latest "S" models, the S standing for slimline and referring to the oil reservoirs narrow 250mm (10in) profile.
Effectively, this has been achieved by placing the control valve blocks at the rear of the oil reservoir, behind a protective shield, which has allowed the designers to get away from the more conventional U-shaped tank.
The effect of the redesign is to bring the cutters centre of weight 250m closer to the tractors axle and spread it across nearly the full width of the power unit – all contributing to improved horizontal and lateral stability of the tractor/hedger combination.
A longer term benefit of the design, Twose maintains, is the heat-dissipating property of the tanks large surface area; better oil cooling resulting in reduced pump, motor and valve wear.
Of more immediate interest to operators is the ability to power slew the boom forward by 10deg – giving a fair degree of crash protection – and to the rear by 95deg, which allows the head to be put into awkward corners and the boom to be tucked neatly within the width of the tractor wheels for road transport.
Operators are also less likely to trap their fingers when hitching and parking, as the improved inherent stability of the machine has allowed an integral stand to be incorporated into the basic structure.
Other design improvements include the use of a fabricated – rather than box section – first boom, tapered at both ends for additional strength.
Ground clearance has also been improved by moving the slew ram from the underside to the top of the tank, a position which also takes torsional loads out of the structure.
In the market the S series supplements Twoses current 460, 520 and 580 models.
Other than the addition of an S suffix, designations are unchanged. Reaches, too, remain the same at 4.6m, 5.2m and 5.8m (15ft 1in/17ft/19ft). As do the choice of version – single or twin pump, with either cable, switch electric or joystick electric controls.
FARMERS WEEKLY climbed aboard a cable controlled single pump 580S mounted on a 100hp John Deere 6400 and went to work among the narrow lanes and high hedges of Devon.
Minimalist
First impressions are a of a minimalist design.
The machine is clean lined and uncluttered. Only the control cables are exposed; where the cutting heads hydraulic pipes do not run inside the parallel linkage arm, they are heavily sheathed and do not sag – no pockets of pipe work to snag on posts or branches.
And the valve blocks sit neatly behind their removable protective shield, which should make servicing a lot easier.
Then it is into the tractor.
Engage the cutting head rotor by lifting and turning a knob on the right hand control console; engage the pto and boot the revs up to around the 1500rpm mark and the hedger is ready to go to work.
On the operators left is the five-lever control bank for the boom and cutting head. Direction of cut – anticlockwise in this case – is selected on the inner, red topped, lever. Slew comes next, followed by boom raise and lower, boom extend and retract, and cutting head rotation.
Levers take a bit of pushing and pulling to get them moving. But it does not take long to get the hang of feathering them at the take up point, to control boom and head functions fairly smoothly and precisely with the tractor going up and down on a typical farm track.
Put the boom out to full extension, and the parallel linkage keeps the head virtually horizontal and there is no excessive tractor lean.
When the boom is fully out or retracted into a into a typical topping position another benefit of the slim design becomes apparent; bringing the machine 250mm closer to the tractor has moved the boom and head forward a similar distance, giving the operator clear sight of the cutting head.
Twose believes the S series is the best hedgecutter it has built – its radical tank design could well give it an edge when it comes to catching the customers eye.