Tanco’s Autocut has turned triple mower design on its head by using a steerable, trailed chassis to carry the two rear cutting beds. Geoff Ashcroft takes a look at development of the outfit.
As triple mower designs go, Tanco’s Autocut system represents a break from tradition. Where most rear mowers used in a triple mower set-up are of the butterfly configuration, carried on the tractor’s rear linkage, the Autocut design sees the rear units carried on a trailed chassis.
The chassis design mimics that of a twin rotor rake. While the front-end of the trailed unit is carried on the tractor’s lower linkage arms, the rear-end follows with an actively steered rear axle. It is a concept that has been in prototype form since 2013 and was the brainchild of County Tipperary contractor John Kennedy.
In addition to his contracting business, Mr Kennedy also owns Stealth Manufacturing and has produced many prototype machines in conjunction with HiSpec Engineering.
“As a silage contractor, I am always looking for ways to do the job more efficiently, or make use of the tractors we have,” he says. “Back then, it was a New Holland T6030 and had we bought a conventional butterfly mower, we would have needed a much bigger tractor, more so for stability than power.
“It seemed logical to get the weight off the tractor, so we could have a triple mower on a smaller, lighter tractor,” he says. “And with horizontal folding for the rear mowers, it is a concept that easily lends itself to using 4m or 5m mower beds.”
The outfit was eventually prototyped by HiSpec, for which Mr Kennedy also provided the Kompactor push-off trailer, with a red liveried, trailed, triple mower revealed at the 2016 Irish Ploughing Match.
With HiSpec not known for its grass machinery products and Tanco looking to add to its bale wrapper portfolio, an agreement was reached for Tanco to build and market the mower. Tanco’s UK and Ireland sales manager Michael Dollard explains: “We took over the design and manufacture in 2017, with a focus on making the unit look more mainstream, to sit alongside our range of bale wrappers.”
As such, the mower gained a restyled frame and a more sophisticated look, with pre-series models now starting to appear, albeit in limited numbers. “With a couple of machines completed for field evaluation last season, we successfully demonstrated models in Ireland, gaining a lot of interest for the 2021 season,” says Mr Dollard.
There are currently two models in the range, offering maximum cutting widths of 8.9m and 9.9m. The wider model uses a nine-disc mower bed, where the smaller model has eight discs. Both mower beds are centrally hung to take full advantage of contour following.
Bed suspension is through a hydro-pneumatic system, offering adjustment of ground pressure. Both units are equipped with semi-swinging steel tine conditioners, with adjustable swath vanes allowing grass deflection and swath width adjustment.
Drive to both mower beds is via T-shaped gearbox, maintaining as level a driveline as possible to save power, while three V-belts run the conditioning rotors at a speed of about 850rpm. The firm says tractors with as little as 180hp could power the smaller 8.9m unit, which means a large-framed, heavy tractor is not required, just to carry the mower.
“In transport, the two beds swing rearwards horizontally, which keeps the overall height well below two metres,” says Mr Dollard. “This also puts some of the weight on the trailed chassis’ rear wheels – again, keeping a lot of implement weight off the tractor.”
He says that in work, weight distribution of the 8.9m machine sees approximately 1,400kg carried on the mower’s rear wheels, leaving a modest 2,000kg to be carried by the tractor’s rear linkage. The 9.9m model weighs 200kg more.
“It is one of the reasons why you do not need such a big tractor to handle this triple mower – the lift capacity is not needed,” he adds.
Operation of the rear steering is by mechanical linkage, which connects the steering headstock to the rear axle. But in a twist of innovation, the rear steering axle also comes with two rates of response for its steering speed. It can be equipped with development called over-steer.
This is achieved through a variable pivot point for the steering linkage. Lifting the mowers when in work automatically moves the pivot point to create the most responsive setting. This affords fast, tight turns on headlands and achieves a 40-degree steering angle, tracking the tractor’s rear wheels.
Folding the mowers for transport reverts the pivot point to its original position, resulting is a slower rate of steering. This is claimed to improve stability when on the road. “The trailed frame follows very well on the road, and does not cut corners,” says Mr Dollard. “If you can get the front of the tractor through a gateway, the rear will simply follow the tractor.
“We also have an option called over-steer, which sees a hydraulic ram used as the rear axle’s steering link,” he says. “Connecting this ram to a spool valve allows you to take control of this function – it is handy on side slopes and to manually steer the unit in very tight spots or extremely sharp headland corners.”
Up front, the matching unit is Tanco’s 7DC, which was developed in 2018. This seven-disc, three metre unit, with pull-type suspension, also includes a semi-swinging steel tine conditioner. A split-drive gearbox sends power to both sides of the mower, where one side runs the disc bed and the other drives the conditioner rotor. Both guards fold up manually for transport.
This front mo-co offers 17 degrees of lateral float and 19 degrees of tilt from front to rear. In addition, 960mm of vertical travel is available. “This unit will cope with some pretty challenging terrain,” explains Mr Dollard. “There is a lot of movement built-in to ensure a clean cut is maintained on uneven surfaces, to match that of the rear mowers.”
When it comes to control systems, the firm says it is currently working on an IsoBus system, though, it is still a couple of years away. It should add extra functionality for those who want plug and play compatibility, but the basic hydraulic version runs off two double-acting spools to manage raise/lower in work, and fold/unfold for transport.
The process of moving between field and transport settings also raises and lowers the guards hydraulically, keeping the overall width to about 2.65m.
A third spool is required for the over-steer function, while a single acting spool valve is needed for the front mower. Prices for UK buyers are still to be announced, and demonstrations are hoped to follow, based on Government travel restrictions being lifted.
Contractor James Fitzpatrick from Cork has invested in the Tanco Autocut to replace a front/rear six metre combination. Used on the same McCormick X7.660 tractor, he says output is up by 50 per cent while using 23-25 per cent less fuel.
“The cost savings are already being felt,” says Mr Fitzpatrick. “We got a demo of the pre-series mower through our local dealer and I was not sure what to expect, but I was impressed from the word go.
“The trailed chassis and axle spreads the weight between the tractor and the mower wheels. And the improved flotation of the mower beds, plus straight drivelines, results in a reduced power requirement and lower fuel consumption.
“It has made a huge difference to my business,” he says. “Upgrading to the 8.9m model was a no brainer.”