D7E Track-Type Tractor Operating Technique Information Caterpillar

Angle Blade

Illustration 1	g00522781

Angle bulldozers are excellent for widening fills, backfilling ditches, or windrowing material in one direction and maintaining forward motion at the same time.

Straight Dozing

Illustration 2	g03712059

Straight Dozing - Maintain a level cut for the best performance. Fill the bulldozer blade. Carry the load to the dump.

• Avoid lugging or stalling the machine.

• Avoid excessive spinning of the track.

• If turning the machine with a loaded blade is necessary, use the bulldozer tilt cylinders instead of the steering lever to steer the machine.

When you are performing leveling work, a full bulldozer blade manages better than a partially loaded bulldozer blade.

Slot Dozing

Illustration 3	g03712074

Slot Dozing - When you trap material in a slot, you can carry larger loads in front of the bulldozer blade.

The depth of the slot should not be deeper than the top corner of the bulldozer blade.

Illustration 4	g03712581

Start the slot at the dump or the spoil end and work rearward. See Figure (A) in Illustration 4. You can load the blade as you are moving downhill. Also, you can then carry the load on a level surface. The technique that is shown in Figure (B) is not as efficient as the technique that is shown in Figure (A). In figure (B), the machine is pushing a load uphill and the operator does not utilize the slot. Dozing level through the entire pit is inefficient because the average distance for pushing the material to the dump will be greater.

Illustration 5	g00040628

When you are digging parallel slots, the center should be removed from the rear. This procedure permits the operator to maintain a slot until the center is removed. The center berm should be wide enough to stand up without collapsing. Maximum width should be 1/3 of the bulldozer blade.

Machine on a Slope

Machine on a Side Slope

Illustration 6	g00040630

When possible, work on a slope vertically. This method is better than working horizontally.

When you are working on banks, use caution. When you are working on slopes, use caution. Avoid tipping the machine.

If the machine starts to sideslip on a slope, lighten the load and turn the machine downhill.

If you are working horizontally on a slope, start at the top of the slope. Work downhill. Maintain a windrow of material on the low side of the machine in order to provide stability.

Use caution in order not to undercut the slope. Undercutting the slope will increase the slope.

Machine on an Up Slope or Down Slope

Illustration 7	g03712093

Reduce ground speed of the machine to an acceptable level by using the service brake prior to initiating a steering correction.

Do not allow the engine to overspeed when you are unloaded and moving down a slope. Watch the tachometer and use the service brakes. Use the service brakes near the top of the slope to prevent excessive engine speed.

Note: When you approach engine overspeed, the action lamp will flash. If the engine overspeeds, the action lamp will flash and the warning alarm will sound.

V-Ditching

Illustration 8	g00040633

V-Ditching - Tilt the bulldozer blade in order to start the desired slope. Position the corner of the bulldozer blade in the center of the ditch. Cut to the desired depth.

Backfilling

Illustration 9	g03712102

Backfilling - Push the material at a 90 degree angle in order to fill a trench. When you are cutting material with the side of the blade, use caution so that the remaining material does not fall on the machine.

Land Clearing

Illustration 10	g03712109

• Beware of all dead limbs. Beware of all limbs that are hanging overhead.

• Cut the roots of the tree in order to fell a large tree.

Illustration 11	g03712115

• If additional leverage is needed, you can doze a small ramp near the base of the tree. The ramp allows the machine to make higher contact on the tree. Push the tree in the direction of the intended fall. Advance cautiously. The ball of the root may hang up under the bulldozer blade. This movement could drag the machine off the ramp.

Stump Removal

Illustration 12	g03712275

Stump Removal - Make sure that roots are cut or loosened. Remove the stump by pushing or digging.

Ripping

Use FIRST speed range for ripping operations. Use additional shanks instead of increasing the speed or higher speed ranges.

Use the decelerator in order to match the drawbar pull. Also, use the decelerator in order to prevent spinning the track.

Rip the ground as deep as possible. Sometimes, you may rip at partial depth. You can remove the material in natural layers.

The sizing of the material is controlled by the depth of the pass and by the width of the pass. If the material is loaded with a wheel dozer, the size of the material should be smaller. Finally, the material should be smaller if the material is loaded into a scraper.

The multishank ripper is intended for high production. Use the multishank ripper in hard, packed soil and loosened, embedded rock. The multishank ripper is for use in material that can be ripped with AT LEAST two shanks. Use the multishank ripper with a single center shank less than 20 percent of the time.

The multishank ripper is NOT intended for high production in rock with a single center shank.

A single ripper shank in an outside pocket of the ripper is NOT recommended. If necessary, locate the shank in the highest position. Operate the machine at reduced speed. The frame of the ripper is not designed for ripping with a single outside shank at full horsepower.

The multishank ripper is NOT intended for ripping in deep applications. Only use shanks of the specified length.

Use a single shank ripper when deep ripping is required.

Packed Soil, Hardpan, Clay, Shale, or Cemented Gravel

Illustration 13	g03712304
Multishank ripper with three shanks

Three shanks work well in these materials. Use the greatest possible number of shanks to break the material to the desired size. However, the number of shanks that are used should not cause the machine to stall.

Rock with Fractures, Faults, and Planes of Weakness

Illustration 14	g03712355
Multishank ripper with two shanks

The use of two shanks will cause the rocks to break out in smaller pieces. Then, the machine can manage the job easily. When the machine begins to stall, use only the center shank. If the tracks spin, use only the center shank.

Single Shank Ripper (Solid Rock, Granite, or Hard Spots)

Illustration 15	g03712399

Use one shank in material that tends to break out in large slabs or in large pieces.

Ripper Shank Adjustment

The length or height of the shank on the ripper is adjustable.

Illustration 16	g03712437

Adjust the length of the shank according to the following procedure.

1. Maintain a length of the shank so that the machine can efficiently pull the shank through the material.

2. Maintain sufficient clearance under the lower ripper frame. This clearance will prevent the machine from catching on large slabs or on large rocks that are brought to the surface.

3. Keep the lower frame assembly as parallel to the ground as possible. This action will evenly distribute the stress.

4. When you remove material with a scraper or with a loader, shallow ripping is recommended.

5. When you are ripping for a scraper, rip in the same direction as the scraper that is being loaded.

6. Never rip to a deeper depth than the depth of the material that is being removed.

7. When you are removing material with an excavator or with a bulldozer, deep ripping is recommended.

Push Loading

Illustration 17	g03712516

1. Contact the push block squarely.

2. The machine should not be moving more than 5 km/h (3 mph).

3. When possible, maintain a straight push.

4. Do not allow the rear of the scraper to come off the ground.

5. When the cut is complete, upshift the machine in order to help the scraper get out of the cut.