January 2001 - Logging and Sawmilling Journal -

Custom ordered for the application, the first two Caterpillar 966G high lift log loaders delivered in BC are working away now at Riverside Forest Products mills in Kelowna and Armstrong. Both loaders are specially equipped for handling the short, eight-foot wood lengths processed at the two plants, each of which has separate plywood and sawmill operations. Referred to as "clam Cats", the 966G units feature a clam style grapple with a 1.25 cubic yard capacity and a highlift boom.

Jack Kotowsky, central shops supervisor at the Kelowna plywood operation, notes that a succession of similarly configured 966 units have been in use at the two plants for some years, with Riverside personnel closely involved with BC Cat dealer Finning in developing and then refining the machine for the application. "These two latest machines are actually the culmination of what has been an ongoing process through the years in terms of modifying the loader for our use. The clam Cat idea started back in the mid 1970s when we began processing blocks instead of logs. We got our first 966 clam Cat in 1975, with a Finning boom and grapple designed to our working specs and have been using them ever since.

The application hasn't changed much at all over the years, but the machine has changed quite a bit." Kotowsky says the biggest changes through the years have involved the boom and grapple, both modified in tandem with the design changes Cat made to the 966 in succeeding models. "The 966 has gradually gotten bigger and more powerful," explains Kotowsky. "Among other things, that has enabled us to go to a heavier, stronger boom and a bigger capacity grapple. This has been a gradual process, usually as we replaced older machines. I think with these two new machines that we're now getting close to the ideal design for this application.

The main job of the 966G "clam Cats" is to work the log collection bins at the Riverside mills. "The loaders keep the bins tanglefree and keep moving the blocks to the surge pile or directly into the mill," says Kelowna log yard supervisor Chris Kushner.

Certainly they are a lot more productive now than the loaders we started with." Although differing in some respects, the log processing and optimization systems in use at the two plants are essentially the same. Sawlogs go to a debarker, then through a slasher deck where they are cut into the eight-foot lengths (with some trim allowance). After trimming, the blocks are scanned for diameter, then sent down a belt to the sorting bins where they are swept into the appropriate bin. "The main job of the clam Cats is to work the log collection bins," says Lou Bouwmeester, maintenance superintendent at the Armstrong complex. "Cut blocks either go directly into the sawmill or to the bins. The loaders remove excess blocks from the bins and carry them to the surge decks.

They also feed the mills from the surge decks as required." Bouwmeester explains that while the slashing station produces about 16,000 blocks per shift, the mill generally consumes about 18,000 blocks per shift. "The log cutup operation runs three shifts a day while the mill operates two shifts a day. The clam Cats are really pivotal to the operation, because if one of them goes down, the sawmill quickly finds itself without an adequate wood supply." At Kelowna, log yard supervisor Chris Kushner says the mill uses essentially the same system, and processes similar volumes as Armstrong. "We have three clam Cats moving blocks from the sort bins to the surge decks and from the surge decks into the mill." Kushner says with the loaders' high lift boom and clam grapple, bin servicing is quick and there is minimal fibre loss through handling. "The loaders keep the bins tangle free and keep moving the blocks to the surge pile or directly into the mill. These loaders are designed specifically for this and they are a very efficient machine in this application."

Although the G series 966 features a number of Cat improvements, Kotowsky says the most significant change involves a custom modification to the lift cylinders, done by Finning's engineering department. "With our old machines, we kept breaking the trunions, partly because they weren't heavy enough for the torquing and twisting involved and partly because the loaders are running on rough ground out in the log yard. "One of our people at Armstrong, Warren Gould, suggested repositioning the trunion lift cylinders. We talked it over with the Finning engineering people and they redesigned the front end with the new machines to address the problem." These units have long been considered an "operator's machine'' at both plants. Changes with the 966G include a tighter turning radius, improved stability and better all-round visibility. Command control steering (with a tilt and telescoping steering wheel) significantly reduces operator fatigue.

Other new features include optional automatic or manual shifting; all hydraulic controls; an air support seat; and changes to the braking system. The 966G is available with two operator control configurations: conventional steering and Command Control steering. Conventional steering provides low effort steering by producing pilot hydraulic flow when the operator rotates the steering wheel. The system uses pilot hydraulic attachment (grapple, bucket, forks) controls. Command Control steering incorporates hydraulics and a mechanical feedback system to directly link steering wheel position to articulation angle. Command Control steering features nearly half turn steering for fast response, precise control, low steering efforts, and reduced steering "busyness". The result is less operator fatigue and increased productivity.

The command control steering on the 966G received praise from operators, who liked its more responsive turning which requires less steering effort. The difference in arm, shoulder and neck strain at the end of a shift is considerable.

Transmission controls are integrated into the Command Control steering wheel for one hand operation. The operator can keep one hand on the transmission controls in all steering positions. This configuration includes electrohydraulic bucket controls which provide precise fingertip lift and tilt control. Controls are mounted on the end of the adjustable right armrest for comfortable operation. Lift and lower bucket kick outs are adjustable and programmable from the operator's seat. The electronically controlled bucket stops are cushioned, reducing bounce and operator fatigue. Other in cab changes with the G series loader include more room and 50 per cent more glass for added visibility. Bonded front windshield glass eliminates the old metal window frames, improving front visibility. A sloping engine hood improves rear visibility.

The 966G also has more power and torque rise, with a Cat 3306 DITA direct injection, turbocharged, after cooled diesel producing 235 hp. Dramatically increased torque rise (60 per cent) means the engine actually develops more than its rated hp it produces 253 maximum flywheel hp as it is lugged back in the working range. The result is added lift and breakout power and better rim pull. Armstrong operator machine Mike Richoux describes the new loader as smoother riding, more responsive and easier to operate. "One of the things I like most about it is the command control steering.

The old 966s had a suicide knob on the steering wheel and it took several turns to go from full left to full right. With command control, I can move full left to full right with a 70 degree turn of the steering wheel." At the end of a shift, the difference in arm, shoulder and neck strain is considerable, he notes. "There is a lot more control system computerization with this loader you expect that with a new machine and it makes them easier to operate. One change I particularly like is that if you hit the reverse switch by accident, the machine doesn't immediately change direction. Instead it slows down and gently shifts into reverse on its own. That's a lot easier on both the operator and the machine. "The loader is also a lot more responsive," he adds, "and Cat has made some changes in the suspension system, so you don't get shaken and jolted around like you used to in the log yard, which is unpaved. From an operator's point of view, this machine is a dream to run, really, especially compared to older models.''

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Refining the Loader

BC's Riverside Forest Products has been refining the "clam Cat" loader concept for 25 years and the company says the new 966G is the best one yet