Doze More Dirt

Challenge conventional thinking and reevaluate your production dozing. Making every move count calls for working back to front

Construction Equipment - November 1, 2005

Larry Stewart
Executive Editor

Read page 1: Slot dozing and other efficient bulldozer techniques

Van De Veer adds a special reminder to stay alert when finishing.

"When you're finish dozing, you usually have grade checkers or other laborers on the ground, you're working in a confined area with grade stakes, and maybe curb and gutter or drain tile. You can get pretty focused on the blade and the job in front of you, but you have to pay attention behind when backing up."

A crawler dozer's basic design makes the machine a prime candidate for working where other machines fear to tread. They're not immune to danger, though.

"Low center of gravity and power in the tracks make crawler dozers excel in slope work — working in areas that other machines can't or shouldn't touch," says VISTA's Tips videotape. "But know your machine's limits. Rollovers are a leading cause of injuries and fatalities."

Caterpillar's equipment-training program for crawler dozers admonishes operators to work more slowly on slopes, keep attachments low, and work up and down slopes if possible.

"Don't think you can jump clear of a tumbling machine," warns VISTA. "Always wear your safety belt and make sure the ROPS is in good condition.

"When pushing dirt off a high wall or a steep slope, don't push each load over the edge," the Tips video recommends. "Leave one blade load at the edge to act as a stop. Let the second blade-full push the first one over the edge. This keeps your machine back away from danger."

When you're working down a slope, remember that gravity can be your friend.

"Pile several loads at the brink of the hill, then push them down the hill in one pass," VISTA recommends. "You'll be able to move more material.

"Keep the machine under control at all times. Many newer machines have hydrostatic transmissions with automatic holdback. But on machines with torque converters, never coast downhill in neutral, and don't change gears while going downhill. Save the wild rides for the amusement park."

Van De Veer reminds slope workers to check machine manuals for recommended adjustments to oil levels. Working on certain inclines, a sump that's not properly filled can leave the oil-intake high and dry and the engine starved for lubricant.

Clearing trees is another potentially dangerous job for which crawler dozers are remarkably suited. Make sure the dozer's falling-object protective structure (FOPS) is in good condition.

Look for a tree's natural direction of lean. It will be the best direction to push the tree. Adjust the direction of fall to avoid obstacles. Check the tree for dead branches that could fall.

Sever roots with a series of V cuts. VISTA recommends leaving the roots on the intended direction of fall untouched. They should act as a hinge, controlling the tree on its way to the ground.

Push the tree over with the center of the cutting edge, raising it high to improve leverage.

"When the tree starts to fall, reverse the dozer quickly to avoid the rising root mass," says VISTA's Tips video.

Large stumps can be uprooted in similar fashion. Although with no risk of a tree falling on the machine, you can V cut roots all around the stump for easier removal.

One key that operators hold to improving crawler-dozer efficiency has nothing to do with operating technique. It's maintaining track-chain tension, and it can reduce undercarriage wear by 50 percent. Caterpillar field surveys have found 20 percent of tracks too tight.

Operators are crucial to long undercarriage life because chain tension can require more-than-daily maintenance. Chain tension is judged by measuring sag — the amount that the track hangs down between the sprocket and the idler, or the idler and carrier roller. Operator's manuals include the recommended amount of track sag, and describe how to adjust chain tension.

There is no regular interval for checking chain tension. When mud starts packing in the sprockets — whether it rains, or the tractor hits a wet layer of earth, or the haul trucks start dumping wet spoil in the fill — someone has to stop and adjust chain tension.

Conditions may change again before the day's out — the spoil starts coming dry, or the tractor moves to higher ground, or the sun heats up and the wind starts to blow. To keep the loose chain from binding in front of the idler, the tension must be adjusted again.