Stable full of workhorses: 2000 skidder guide

Canadian Forest Industries, Jun/Jul 2000

With new skidder lines introduced by the major manufacturers, and complete new models coming on-stream from the up-and-comers, the timing is right for a look at what's available in industry workhorses. One immediately noticeable trend in one market segment is to larger skidders, capable of larger payloads, much longer skids, and when used properly (i.e. modified planning & roadbuilding) reduced environmental impact. Another trend worth watching is the introduction of six and eight wheel drive grapple skidders, with bogie technology used for reduced impact on both operator and terrain. If coupled with larger payloads and worked in mushier, hard-to-access ground conditions, these units may prove more than able to pay for the extra hardware. Tigercat, Timbco, and Trans-Gesco all have new models of grapple skidders with 6WD or 8WD configurations, and you can find a field report on Trans-Gesco's latest on page 30. Rumours abound of other manufacturers testing their own bogie-clad grapple skidders, but we at CFI are loathe to spread rumours.

Two final notes: All major skidder manufacturers with a market presence in Canada were asked to supply information for this issue, and almost all did. There were a few exceptions, and perhaps we will include them in an upcoming issue. The information included here was supplied by the skidder manufacturers, and has not been verified by CFI, so it's Buyer Beware.

Tigercat 620 Grapple skidder -- Cummins 6BTA5.9-174 hp

The mid-sized 620 hydrostatic skidder is quick and very manoeuvrable; applicable both to thinning and final-fell operations. The 620 is available with the Tigercat 1.1 m[Symbol Not Transcribed] continuous rotation bunching grapple on a single function arch.

The hydrostatic drive combined with Tigercat's single-range transfer case provides infinitely variable speed control from 0-21 km/hr and offers a number of advantages. Maximum horsepower is always available, regardless of wheel speed. Gear shifting is eliminated for reduced operator fatigue. The operator simply applies one pedal to travel forward and the other to reverse. Smooth starts and stops minimize wheel spin and cause less stress on the driveline components.

The isolation mounted tilting cab is quiet and spacious with air conditioning, adjustable suspension seat and one low effort joystick controlling all arch and grapple functions and the independent differential locks. The seat and all controls are rotated 40[Symbol Not Transcribed] to the right for reduced neck strain and a better view of the load.

Service access is enhanced by the tilting cab and the unique engine orientation, which situates the pumps and filters at the front of the machine, easily accessed via the strong front door. The heat exchangers are located in a well-protected position in front of the cab.

Tigercat 630B Grapple skidder -- Cummins 6CTA8.3; 240 hp aftercooled

A high production skidder, the 630B is best suited to rough terrain, slopes, long distance skidding and extreme duty cycles. Choice of grapples include the 1.3 m[Symbol Not Transcribed] and 1.67 m[Symbol Not Transcribed] continuous rotation bunching grapples. Grapple components are oversized and structurally superior. The long wheel base and "pump-forward" engine orientation provides the stability necessary to handle larger loads than competitive skidders.

The 630B is equipped with Tigercat's innovative cross-flow cooling system, also found on the 635 and 640 models. The system orientates the side-by-side radiator and oil cooler perpendicular to conventional arrangements. Air flows sideways, passing unobstructed over the coolers. Airflow is accomplished with a hydrostatically driven reversible fan. The operator-controlled variable speed allows for improved fuel efficiency in cold conditions where full fan rpm is not required and is advantageous for cold weather start-ups. To avoid debris build-up at the air intake area, the operator can reverse the fan -- without leaving the cab -- to quickly purge the coolers.

The hydrostatic drive, combined with Tigercat's single-ratio transfer case, provides infinitely variable speed control from 0-16 km/h and offers similar advantages as with the 620. Similar too is the ergonomic cab design.

A hand-operated lever to adjust maximum speed allows the operator to effectively reduce the maximum speed of the vehicle while maintaining the full range of foot pedal travel. This new feature provides even more precise control of the skidder in extremely rough terrain. The 630B is cost effective because it can pull more wood in fewer trips -- the key to higher productivity. For more info circle reply card no. 6

Tigercat C640 Clambunk -- Cummins 6CTA8.3; 240 hp aftercooled

The C640 clambunk skidder is an extremely efficient transporter for sensitive site applications and long distance skidding. It comes with a Tigercat 2.97 m[Symbol Not Transcribed] clam. The machine can pull two to three times as much wood per load as conventional skidders because the large capacity clam elevates the load for less resistance. Fewer trips result in less time spent travelling empty for improved productivity. Also, because the machine idles during loading, it is fuel efficient.