Forest Renewal BC
By John Dietz
The single-grip Rocan-T thinning harvester used in the Avenor show, manufactured by Rocan in New Brunswick weighs just 12,000 lbs. and is just 2.2 m wide. The machine utilizes the sub-frame of a New Holland 9030 bidirectional tractor, originally produced at Winnipeg under the Versatile name.
The chassis-short, narrow and robust - "makes a fairly good little woods machine," says Rocan president Allan Anderson. Twenty of the machines have been built since the prototype was developed in 1993. Power is supplied by a 100-hp, turbo-charged engine. A three-speed hydrostatic drive transmission offers a top speed of 30 km/h.
Says Anderson, In small trees, these machines are much faster and productive than counterparts that are three times bigger." The frames, with fixed axles, are intended for good to medium terrain. Tires have very aggressive tread patterns, be added for more traction. A Mowi 465 parallel loader, made in Sweden, is mounted on the 9030 chasis. "It looks like a knuckle boom, but it acts like a telescope," says Anderson. The self-leveling loader is able to move the head straight ahead, parallel to the ground, while the operator works a single function.
"You can work very, very close to the machine. For example, you can cut a tree just three feet from the front tire."
The loader has a 6.6-meter reach, with a lift torque of 575 kg at full extension. A Pan 828 head, made in Sweden by Grangarde Maskin Ltd., does the CTL work. It's built for trees in the 6" to 12" range. Full 360' swivels are routine for the head rotator.
Another Swedish component, the Voac L90 load-sensing hydraulic valve, was chosen for reliability and sensitivity. Sensitivity can be adjusted for individual operators. Anderson says, "It's one of the newest valves on the market, with very good operating characteristics. It's very smooth, operates at low temperatures, and doesn't create any heating in the system."
Rocan installs a simple, easy-to-use computer for the CTL system, The Omron C-40 offers four length pre-selections, which have been adequate for the thinning work done by the machines.
The electric-over-hydraulic aspect is popular with Storkson's operators, who were specially trained on these machines. He says, "All our switches feel like they're hydraulic but they're not. You can set the sensitivity, like a joystick for a computer game." The machine's onboard computer can store different operating preferences for up to four operators, another popular feature. says Storkson.
The re-set button is another feature that makes life easier for the operator. "By hitting one button, the computer re-sets the head. It stands the head up, opens the knives, opens the rollers and gets everything ready for the next tree."
Rocan also imports the Rottne line of forwarders and 'cut-to-length' (CTL) harvesters from Sweden. Rottne forwarders and CTL harvesters are made in Rottne, Sweden. Rocan began importing the machines in 1984, introducing the CTL concept to North America. Approximately 265 Rottne machines have been imported by Rocan since then.
The Rottne-G is classed as a 10-ton, eight-wheel-drive forwarder with a bunk capacity of 10 M3. It's built on a 12-ton subframe, only 2.6 metres wide. The nine-gear bogies on the machine are from a 12-ton forwarder but the cast boxes are narower so the machine can work inside narrow, thinning trails. Anderson says despite that profile, the machine is heavy- enough to stand up in rugged conditions.
The 120-hp machine has a hydrostatic, computer-controlled transmission. Transmission speed and engine speed are governed by the computer. To reduce oil contamination problems, the Rottne-G has separate hydraulic and hydrostatic systems. Oils stay separate, preventing contamination that can happen in a conventional pump-and-motor hydrostatic system. Outboard planetary systems are sealed away from the differential, so contam- ination at one point won't get into the whole system.
Other Rottne forwarders include 12- and 16-ton models, with six or eight-wheel-drives. A nine-ton, eight-wheel-drive thinning forwarder, suited for exclusive use in small thinning operations, will be arriving in March, 1998. On the harvester side, Rottne make four-cylinder and six-cylinder models with either single or double grips. Rocan does some modifications for specific regions in North America.
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