Riding O'er the Waves (of grain)

by Richard Mandel

When you're a custom manufacturer, inspiration sometimes just walks in the door. Of course, it helps when the company is small and flexible enough to respond in kind.

GK Machine, Inc., Donald, OR (a suburb of Portland), is a fabrication job shop for the agricultural market. Started in 1976 by brothers Gary and Keith Grossen, the company has developed and manufactured a variety of heavy-duty farm, nursery and vineyard equipment, alongside their service and repair department for equipment from other OEM manufacturers. Although the two brothers originally worked from their own designs or modified existing machines to meet the needs of a customer, they began putting together a design team in 1989, starting with cousin Dave Grossen.

Farming without a tractor

It was in 1992 that a local nursery operator approached the company for a vehicle that would have the flexibility and ruggedness of a tractor, but wouldn't impact and compress the soil under its wheels. The solution was to use a rubber track drive, which would distribute the weight of the vehicle over a larger area and, as a bonus, would be more maneuverable, since tracked-drive vehicles traditionally can turn in a smaller radius than wheeled vehicles. Thus was the TR2 Tracker born.

TR2 Tracker

The machine sported two 10-in. wide tracks mounted to a mechanism that could change the distance between the tracks while the vehicle was in motion. This gave the vehicle needed flexibility when traversing between fields where crops are planted with larger or smaller spacing between rows. The cab and main drive systems were suspended 36 in. above the ground, similar to the ground clearance of standard field equipment and completely suited to working with row crops and cranberry fields. The TR2's design allowed the machine to turn on its own axis, and the vehicle was offered in two frame widths. Options included systems for crop spraying and distribution of liquid or granular fertilizers. Power for the machine came from a John Deere 115 hp diesel engine, which also drove the power take-off option. When carrying the spray system apparatus, the weight of the TR2 would be about 9,000 lbs, giving the vehicle a solid mass on its center of gravity, while the tracks kept the vehicle's ground pressure down to just
4.4 psi.

TR4 Tracker

The TR2 proved to be a popular design, and is still being manufactured today. However, within a few years of the original production, someone approached the GK staff and asked for a similar machine with a higher ground clearance. This was to be the TR4.

Taller in the saddle

Like its predecessor, the TR4 used a rubber-track drive that could be varied in width while on the go. The tracks were now 12-in. wide, and the two frame widths could allow a maximum track width of 136 in., after maximum adjustment. There was also three choices for ground clearance that with hydraulically-powered variable adjustments gave buyers a selection that ranged from 65- to 97-in. While the TR2 mounted the engine ahead of the operator, the TR4 had a reversed configuration, giving the operator a full view of the work zone ahead. A second John Deere engine, providing 125 hp, was also offered. The sprayer system for the TR4 used two 200 gallon tanks that were mounted like saddlebags above the tracks and below the level of the cab, providing a solid, steady platform. Again, since contact with the ground was entirely through the rubber tracks, the TR4 could rotate on its own axis like the TR2. Weight of the TR4 was 13,000 lbs in the sprayer version. Another version, lighter by 3,500 lbs and with a fixed 78 in. ground clearance, was made for use in vineyards. Implements now ran to include mowers and pruners.

In 1997, GK Machine received an award for design of the TR2 from the American Society for Agricultural Engineering. The same award was presented in 1999 for the TR4 and in 2000 for the vineyard application version of the TR4. The Trackers have successfully moved the company from being a custom job shop to a full-time manufacturer of a product that is internationally marketable.

New drive for GK

Earlier this year, a partnership between Auburn Gear, Auburn, IN, and Denison Hydraulics, Marysville, OH, resulted in the introduction of a family of fully integrated, hydraulically-powered planetary-gear wheel drives for agricultural equipment, as well as aerial lifts and other construction equipment. One of the first to incorporate the drive was GK Machine in their TR2 and TR4 vehicles.

The Model 43 Power Wheel Plus drive uses a Denison 43cc maximum displacement axial piston motor that is installed inside the spindle of the Auburn planetary gearbox. The entire package is less than 15 in. long, as compared to around 24 in. for a conventional bolt-together drive arrangement.

Model 43 Power Wheel Plus

At full displacement the motor delivers its maximum torque. Power varies directly with speed over this part of the operating range. If motor displacement is reduced while the pump volume is kept constant, motor speed is increased. In this operating range, power is constant while speed and torque vary inversely with motor displacement. GK Machine is currently using a two-speed motor version that is offered for the Model 43.

The planetary gearing for the Power Wheel Plus drives were designed to deliver 100,000 lb-in. of intermittent torque, with ratios ranging from 16:1 to 55:1, yielding effective displacements between 692 and 2370cc. Also suited for the needs of machines like the TR2 and TR4 was the use of bearings in the drives that could manage up to a 27,000 lb load, a large diameter heat-treated spindle and ductile iron housing. An Auburn-designed Cone-Loc parking brake built into the drive, which occupies less space than clutch plate-type brakes, has an output torque greater than the output torque of the drive. This would prevent an operator from accidentally "driving through" the brake when it is set.

Use of the Model 43 drive on the Tracker machines has allowed a much narrower line to the design of the tracks. There is also reduced chance for impact damage to the drive, since the motor is safely housed within the gearbox.

For more information:

Circle 430 - GK Machine, Inc. or connect directly to their website via the Online Reader Service Program at http://www.1rs.com/010df-430

Circle 431 - Auburn Gear or http://www.1rs.com/010df-431

Circle 432- Denison Hydraulics or http://www.1rs.com/010df-432