Bulldozers and Other Construction Equipment
By Joan Whetzel
Several types of construction equipment fall under the umbrella term "bulldozer." These types of construction equipment include backhoes, compactors, excavators, motor graders, and skid steer loaders which fall generally into one of three categories - excavators, crawlers, and continuous tracked tractors. The front end of the bulldozer is equipped with a metal blade (called a plate) that pushes the dirt and debris around during the clearing and leveling stage of a construction site. The bulldozer's back end will have one of several other implements to help with other jobs on the construction site. The choice of bulldozers to be used for any construction site depends on the jobs that need to be done.
Excavators are heavy construction equipment consisting of a boom, bucket and cab on a rotating platform. The house (where the driver operates the excavator) sits atop an undercarriage with tracks or wheels. All movement and functions of the excavator are accomplished through the use of hydraulic fluid, be it with rams or motors.
A backhoe consists of two appendages, a shovel in the front and a backhoe at the back end of vehicle. They are usually small in size which makes them quite maneuverable and versatile. The backhoes are used for demolition as well as for construction projects. They are seen frequently in use on road construction sites, and can move materials, dig holes, and clear land for landscaping. the bucket on the backhoe can be switched out for a stump grinding attachment, an auger, a grappler or a rock breaker, which further increases its usefulness.
The compactor type of backhoe minimizes the amount of dirt, debris, and trash on a site by crushing it and compressing it. They are manufactured in a wide variety of sizes that can be used for different sized jobs. The type of compactor most commonly seen are those used in landfills. However, there are other types of compactors:
- · road rollers, used to compact the area before a road is laid.
- · jumping jack compactors, used to pack-in the backfill dirt used to fill in and around gas and water line channels
- · plate compactors, used to level land prior to building and housing construction.
Excavators are produced in a variety of sizes from minis to industrial excavators. The mini excavators are generally used for landscaping projects, whereas the industrial size excavators are used for such jobs as river dredging, mining and relocation of heavy materials. In general, excavators are used in demolition, hole digging and plowing jobs for prepping a site for home construction. The excavator's cab is placed on rotating pivot with a bucket attached to an articulated arm. The wheels are either on a track or attached to the undercarriage. Additional excavator attachments include, augers, breakers and grapples.
The terms grader and motor grader are used interchangeably. Graders flatten, or grade, a site once it has been cleared of grass, trees and debris. These pieces of equipment are seen in construction, forestry, public works, and mining jobs.
Front End Loaders
Skid steer loaders, or front end loaders, operate with wheels or with a track. These four-wheel drive vehicles operate with the right and left sides working independently, which makes it easier for the operator to maneuver the speed and direction with which the vehicle moves. This gives the loaders a zero turning radius. The driver's cockpit is situated in front of the pivoting apparatus and the lift arm and bucket appendage are fixed firmly to the front of the vehicle. Being lightweight and having a tight turning radius makes highly maneuverable and great for working in tight spaces. They can even drive into and dig from inside holes (e.g. "Mike Mulligan and His Steam Shovel").
Absolute Astronomy: Bulldozer