BULLDOZERS: ALL YOU SHOULD KNOW ABOUT THEM AND HOW GPS IMPROVED THEM

The person(s) who deserves the credit for inventing the first bulldozer (dozer) remains uncertain. What is clear is the unarguably positive impact that the dozer creation has had on the construction industry, among others such as farming and mining. The dozer also played a significant role in World War II when small dozers were airdropped by parachutes and used to create runways. The track-type tractor dates as far back as the 1920s, when the Caterpillar Tractor Company was founded as a result of a merger between Holt Manufacturing Co. and Best Tractor Co. CAT quickly came to dominate the dozer market while gaining popularity throughout the 1930s. Dozers started being used on large construction job site projects, such as the Hoover Dam and the Golden Gate Bridge. Today, dozers are one of the most powerful earthmoving machines available and are used for construction projects of all sizes and set the standard for moving dirt and materials and clearing sites.

CAT dozer with a multi-shank ripper and semi-universal blade

Dozer Types

Crawlers, also known as tracked bulldozers, are the workhorse of the construction industry. 

They range in weight from 18,000lbs to 230,000lbs and can come in many configurations. Different blade shapes, rear rippers, and winches can be added to a dozer to help it in its roll. A forestry dozer typically has a six-way blade, canopy sweeps, and a winch. The six-way blade allows the blade to go up and down, twist side to side, and angle right or left, which enables the dozer to build roads on the side of mountains. Canopy sweeps protect the exhaust pipe and cab from low-hanging branches by guiding them up and over the cab. A typical grading dozer will likely be equipped with a 6-way blade, GPS, and a multi-shank ripper. The multi-shank ripper helps loosen hard clay over a wide area. A bulking dozer that moves large volumes of dirt for mass earthworks is usually equipped with a Semi-Universal bade, GPS, and a single shank ripper. A Semi-Universal blade is built to carry material and is shaped in a very shallow "U" shape when viewed from above. A single shank ripper breaks up the toughest materials using only one huge ripper shank. These shanks can rip deeper than multi-shank rippers and can rip through solid rock and frost.

Wheeled dozers look more like a wheel loader with a blade than a standard dozer with wheels. They steer by articulating at the center and have top speeds exceeding 20 mph. They have high ground pressure and are typically only found in mining and powerplant operations. They are great for cleaning up behind power shovels in mines and stacking up coal or woodchips at powerplants.

Low ground pressure (LGP) dozers are tracked dozers with extra wide grouser pads (track segments) that spread the weight of the dozer out over a large area. LGP dozers can work in temperate conditions and tend to tear up a surface less than standard tracked dozers. They are also excellent on steep slopes as they have a much wider track base. There are also "super swampers" and have tracks up to 40" wide. These dozers are used for work in peat farms and swamps.

Dozer Safety & Best Practices

John Deere dozer

There are some protocols that, when followed, will reduce the risk of injuries and possible fatalities! Operators should, of course, always wear their seat belt and follow the lockout, blockout, & tagout procedures. Before starting up the dozer each time, the operator should also check the level of oil and coolant and top them off as needed. Not unlike preventative vehicle maintenance, checking the dozer out regularly will increase its lifespan. Operators should always work front to back (aka work in the slot) and should always use short cuts (as opposed to long cuts, which may seem like it would be more productive, but it's not). Staying away from utilities like power, water, and gas is also a necessary safety measure that should be taken. If the track chains feel too tight, they should be loosened. Otherwise, its normal wear will be much faster. When operating a dozer on a hillside, it is recommended that the operator works up and down on the slopes to prevent a rollover. This technique becomes especially important for those working with older machines that don't have hydrostatic transmissions. Finally, at the end of the long day, dozers should always be locked up with their blade lowered and parked at ground level. Following these safety tips and operating guidelines is more than just good practice; it could mean the difference between the operator making it back to work or not the following day.

GPS

Dozer with GPS

Now, let's get to the good part! It seems unbelievable to us, but it has been over twenty years since the inception of GPS machine control for earthwork! Some manufacturers equip their machinery, including dozers, with GPS. GPS machine control allows for better grade control and more precision. Companies like Trimble and Topcon provide retrofit options for any contractor not in the market to buy new heavy equipment. This aftermarket add-on is a popular alternative to investing in new heavy equipment. Operators quickly appreciated the value of working with GPS dozers because it eliminated the need to have someone nearby checking grades. The operator can get the real-time grade levels through the cab technology. There are a couple of different methods, indicate-only and fully automatic. Their names may speak for the differences themselves, but an indicate-only relies on the operator to manually grade according to the site's design while using GPS positioning information. The fully automatic way incorporates GPS automictic hydraulic control allowing the blade of the machine to be controlled by the GPS guidance system with an accuracy of less than 2cm!

For GPS to work successfully and efficiently in earthwork, there must be accurate 3D models loaded into the dozer or other heavy machinery. GPS has become more of the industry standard, and we expect there will not be many site contractors running projects without GPS on their equipment. The benefits are far too great not to make the switch. When you partner with ECI Technologies, we not only create the necessary files you need but also help you troubleshoot problems that come up along the way. We don't ever leave our clients to figure things out on their own. We have the experience necessary to help you get more accurate bids and more projects completed faster.