Tigercat Adds New Loader Series

Diesel Progress North American Edition, April, 2001 by Brent Haight

Meeting customer demand for greater capacity and increased swing torque, Tigercat has introduced the 250 Series knuckleboom loader. Powered by a Cummins 6CT8.3 diesel engine rated 215 hp at 2200 rpm, the 250 loader is the highest capacity loader in the company's lineup.

According to Kevin Keats, product manager, material handling group, at the Ontario-based manufacturer, the 250 series loader is available in two configurations. "The standard 250 loader is mounted onto a subframe with outriggers that, in turn, is mounted onto a trailer," said Keats. "But we also offer a tracked version. The T250 loader is mounted on a purpose-built, tacked undercarriage with 48,000 lb. tractive effort for moving between decks or traveling infield to retrieve or sort timber."

The 250 and T250 loaders use the same high-pressure hydraulic system that is used in Tigercat's 845B feller buncher.

"The main hydraulic system that operates the boom hoist, stick and swing, as well as the track drives on the tracked version, comprises a Linde HPR 160 high-pressure pump and a modular Linde Synchron Control valve," said Keats. "The maximum pressure is 4300 psi.

"This system is a load-sensing system that delivers power on demand and synchronizes the control of several functions when maximum pump flow is reached. In addition, this system employs an anti-stall system that works as a horsepower limiting control and reduces pump output when the engine speed drops below a set level."

Mounted on the back of the main pump, the auxiliary pump is a Linde HPR75 pressure-compensated pump that operates in an open center system to deliver power to the grapple, stabilizers and an auxiliary circuit. The maximum pressure in the auxiliary circuit is 2600 psi. Oil is directed to the work functions by a Parker Commercial pilot-operated, multispool valve.

The cooling system incorporates an AKG of America aluminum radiator and oil cooler. "We sized it so that people in the southern United States wouldn't have overheating problems," said Keats. "We use a side-by-side layout to ensure the radiator and oil cooler receive cool ambient air." The boom system incorporates high-pressure cylinders that were designed by Tigercat in conjunction with Hydra Dyne of Woodstock, Ont. The main cylinder has a diameter of 7 in., while the stick cylinder has a 6 in. diameter. Each cylinder is cushioned at both ends and contains piston and rod seals.

The swing system is powered by a Linde fixed displacement piston motor that drives through a Linde double-reduction planetary gearbox, giving an output speed of 9 rpm and sufficient torque to meet the demands of pull-through delimbing applications and swinging on slopes, Keats said. The swing system has a heavy-duty slewing ring bearing with a 47 in. ball race diameter and an internal gear.

The 250 series loaders have a maximum reach of 32 ft. At 11 ft. reach, the lift capacity is 35,000 lb. At 25 ft. reach, the lift capacity is 14,000 lb.

The fabricated steel subframe on the 250 loader has a length of 162 in. The support base measures 150 x 183 in. Built-in, bidirectional lock valves are used to hold the 6 in. diameter stabilizer cylinders in place. The electrically controlled stabilizer pads measure 23 x 29 in.

The tracked version of the 250 loader is equipped with a Tigercat designed, purpose-built, forest duty undercarriage. The undercarriage consists of a heavy- duty, high-clearance carbody and track frame with a flat bottom to improve mobility and flotation. The track drives incorporate Bonfiglioli triple-reduction planetary gear boxes driven by Linde piston motors.

Travel speeds for the T250 loader are up to 1.3mph in low gear and 2.5 mph in high. The track rollers, idler, chains and 30 in. triple grouser shoes are from Berco.

Two joysticks control the boom, grapple, slasher and delimber functions. A T-bar type foot pedal is used for swing control. "The operator simply pushes on either side of the foot pedal to swing in that direction," said Keats. "The foot pedal and the joysticks are specifically matched to the requirements of the control valve spools to provide smooth control and operation."

Instrumentation is mounted in a panel above the front window. A warning system monitors engine temperature, engine oil pressure, engine coolant level and hydraulic oil level. If any abnormal conditions are sensed, both audible and visual warnings are given.

"The 250 series loader is a smooth operating machine with more capacity than we've previously offered," said Keats. "It is made for rigorous loading and delimbing applications. The feedback from customers so far has been very positive."