Installing underground utilities is much less labor-intensive than it once was. Prior to the late 1940s, the task of digging a trench was back-breaking work involving shovels and picks and a lot of manual labor. It was slow, too. Then, in 1949, the first compact trencher was manufactured. It was a mechanical, labor-saving tool intended to cut trenches for the installation of underground water lines. What it did was launch the compact trencher industry.
Today, compact trenchers are used in a variety of applications from construction to landscaping. They are ideal tools for quickly and efficiently installing gas, sewer and water lines, telecommunication and fiber-optic cables and irrigations systems. Compact trenchers step in and tackle jobs that are considered too small for a compact excavator.
Skid steer or track loader trencher attachments are fairly straight-forward tools. They consist of a boom, chain, spoil auger and hydraulic motor. Wear items include chain teeth, crumber and drive sprockets. They are operated using the hydraulics from the skid steer. The angle of operation is controlled by the skid steer’s mounting plate – rotate the top of the plate forward to increase the depth and back to decrease. The spoil auger carries dirt away from the trench to prevent it from falling back in. The crumber creates a clean trench floor by returning residual dirt to the chain to be removed.
Skid steer and trencher operation, no matter if you’re a contractor, landscaper or weekend warrior, can be tricky. Make safety job one. Know your equipment, utilize all of their safety features. And first and foremost, know your area. Underground work requires lead time and proper site prep. Buried obstacles, especially gas and electric lines, pose a hazard for operators and bystanders. Before any trenching is done, always call Dig Safe at 811, or reach out to your local utilities if they are not participating members of the program. In most locations, state law requires this call as a first step.
Second, you need to know the power unit. A good operator will be well-versed in the skid steer or track loader controls. Familiarize yourself with all of the controls and in-cab adjustments. Be aware of skid steer safety measures: Read your operator’s manual, always wear your seat belt, keep the loader arms on the ground when parked — never lower the arms from outside the cab and do not leave the operator’s seat while the engine is on. You should also know how to adjust the trencher and make sure all of the moving parts are in good working order. Consult your operator’s manual for a pre-operation check list.
Next, educate yourself about your digging conditions. Is the soil rocky? Sandy? How compacted is it? How wet is it? Once you determine the ground conditions, you can determine a safe operating speed. Damp or clay-based soils require slower speeds, while sandy or loose soil can accommodate faster speeds. Generally, a good ground speed is 1 to 3 mph. Trenching with a skid steer or track loader is done in reverse. Make certain that the area is free of obstacles and that by-standers are not in harms way.
Selecting the proper chain to match your conditions is important. Improper selection can lengthen the job, damage the chain and cause downtime. There are four primary chain designs to consider: 2-pitch, 4-pitch, alligator or scorpion. A 2-pitch cup chain is best for moderately compacted or sandy soil. It offers smooth cutting but will require more horsepower as there is a tooth on every station. A 4-pitch chain has a tooth on every other station and performs well is loamy soil and general every day trenching. Alligator or frost-style chains have bullet shaped teeth and are at home in soils that are highly compacted, frozen or mixes of clay and shale or other easily fractured stone. Scorpion or shark-style chains feature fin-shaped carbide cutters for compacted and rocky conditions; they do not perform as well in softer soils. Whichever chain is selected, make sure it is properly tensioned — in most cases review the operator’s manual for this information.
Ensure that your power unit is up to the task too. Skid steers and track loaders, like tractors, are rated for horsepower and hydraulic flow. Your dealer or rental company should be able to assist in selecting the right attachment for the power unit. For optimum performance, match the power unit to the attachment for flow rate, horsepower and weight.
Before you begin trenching, know that the speed and power for the trencher are supplied by the power unit’s auxiliary hydraulics. For optimum performance, match the maximum gallons-per-minute of the trencher to the maximum flow of the power unit.
Once you are ready to trench, set the skid steer over the area, straddling the imaginary line to be trenched. It will take 3 to 5 ft for the trencher to reach the required depth depending on boom length. Lower the boom into the soil and slowly drive backwards as you continue to rotate the chain deeper in the soil. At this point, the operator should be regularly checking behind the skid steer for obstacles, people or animals that may have entered the area.
Some trenchers have depth guides on them that estimate the depth of the trench. A good rule of thumb is that the trench depth will equal the boom length when the trencher has its skid shoes resting on the ground and the boom is at a 60-degree angle. The spoil auger will keep the soil pushed away from the trench to help keep the trench clean and eliminate extra weight that could cause a cave in.
Caution should be exercised when the trench requires a turn; plan ahead and make a wide radiused turn if possible. If the trench requires a sharp or 90-degree turn, dig two trenches. The reason for avoiding tight turns is that it will add side load to the trencher, possibly damaging the frame or boom and will cause wear excessive wear on the drive sprockets and chain teeth.
When the trench is complete, remove the boom from the trench like it went in. Rotate the skid loader plate back toward the skid steer bringing the boom to level to free it from the trench and raise the loader arms to life the skid shoes off the ground. Reduce the engine speed and to slow the chain to a stop. Never leave the skid steer until the attachment is on the ground and the chain has come to a complete stop.
No attachment tips article would be complete without maintenance tips. The surest way to guarantee that your trencher will be a useful tool for years to come is to properly maintain it. Proper maintenance equals optimum performance. Replace wear items as needed. Chains are in abrasive conditions — keep the chain teeth sharp, replace broken teeth and lubricate according to the operator’s manual. Skid shoes and the crumber should be regularly inspected and replaced at the end of their service life.
With patience, practice and maintenance your trencher will be a valuable and profitable tool in your fleet.
Dee Warren is the marketing manager for Land Pride. Click here for more info!Tags: Land Pride, Your Utility Construction Connection