Case 2050M Operator's Manual page 151

6 - WORKING OPERATIONS
Low Impact
Track shoe grousers will completely penetrate the ground surface with little or no rock or other irregularities.
High Impact
Track shoe grousers will not penetrate the ground surface. Large rock or large irregularities cause high impact on
the undercarriage system. Rocky terrain causes bending, breaking, and chipping of the components. Reduce the
machine speed, and use the smallest track shoes possible.
Packing
Packing materials are materials that stick to or pack around the moving components. Tracks must be adjusted as
often as required when working in this type of soil condition.
Packing materials cause a mismatch between components, particularly between the chain and sprocket. The packing
materials tighten the chain causing increased stress and strain on links, pins, bushings, and the contact surfaces
between mating parts. As mismatch occurs due to packing in the sprocket root, each track bushing rides higher in
the sprocket. This condition causes rapid and severe forward and reverse wear, and a chain to sprocket "jumping"
that is indicated by a loud "banging" and/or "popping" noise. This results in high impact loads that cause additional
wear and cracking.
Packing conditions can also stop rollers from turning. When this happens, the track chain slides over that spot on the
roller causing a flat spot. Packing materials increase the abrasive effect of most material by not allowing the material
to escape. Wear will be accelerated.
When a packing problem continues, install relieved track sprockets.
Intermittent packing can also occur between some of the sprocket teeth. Intermittent packing can cause the track to
tightened and release rapidly. This will cause the recoil spring to compress and release. A loud "banging" noise will
result.
Extreme reverse loading
Extreme reverse loading occurs when the machine backs uphill. The top of both track chains become tight, com-
pressing the recoil springs. When the machine is driven forward, a loud "banging" noise may occur as one or both
recoil springs release.
Track Shoes
The shoes must provide adequate traction and flotation, but should be no wider than necessary. Flotation is the ability
to stay on the surface of soft ground or mud. Correct flotation occurs when the grousers penetrate fully into the ground
without letting the track shoes go below the surface.
Track shoes that are too wide can have a damaging effect on many of the undercarriage components. The middle of
the track shoe is fastened to the track links, and the links act as a fulcrum and must absorb or transmit any leverage or
twisting forces that occur as the machine moves over uneven or rocky terrain. All of the other components (sprockets,
track rollers and idlers) resist and restrict the twisting forces of the links. This results in wear and damage caused by
the twisting action. The twisting action can also damage the links, pins, bushings, and track plate mounting hardware.
Wide track shoes effects:
1. Resistance to turning - results in wear on the shoe corners and twists the track chain.
2. Bending, cracking or breaking the track shoes, shoe hardware and links.
3. Constant problems with loose shoe hardware that makes the bolt holes larger.
4. Increased wear on links, roller flanges and idler flanges caused by a constant twisting of the track chain.
5. Decreased pin and bushing life or decreased link life due to elongated pin and bushing bores. This is a result of
the twisted links.
6. Possible loss of lubricant in the Lubricated Track pins. This will result in early pin and bushing wear.
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