What Is a Construction Bulldozer?
A construction bulldozer is a piece of construction equipment used mainly in construction work to remove, transport, and level the ground.
A bulldozer is a heavy machine with an earth removal plate called a blade attached to the front of its body. Its main role is to push earth and sand in the direction of travel to level the ground. By changing attachments, the bulldozer can perform various types of work. There are two types of drive systems: crawler (infinite track) type and wheel type.
Uses of Construction Bulldozers
Bulldozers are used for earth removal, pushing, and leveling in construction work. These include civil engineering, dam construction, building construction, and site development. They are also used for snow removal and wetland work. By changing attachments, bulldozers are used for digging up and moving large rocks, root cutting, etc.
Bulldozers are available for special work. At disaster sites, they are operated by radio control. Amphibious bulldozers work by radio control and are used in places where dredgers cannot enter or leave. Underwater bulldozers can travel on the seabed and are remotely controlled by divers.
Principle of Construction Bulldozer
Pushing earth and sand out of the ground requires a great deal of force and driving power. Crawler type bulldozers are often used because of their high driving force. The gears are reduced along with the engine speed to produce powerful propulsive torque.
To dig up and crush large rocks, a jaw called a ripper is used. The ripper helps break up rocks and separate rocks from sediment. Bucket-type blades can efficiently transport sediment.
Operations using blades require the blade to be tilted from the vertical or oriented to the left or right relative to the direction of travel. Hydraulic pressure is used to change the angle of inclination.
Features of Construction Bulldozers
1. A wide variety of attachments
By changing attachments, various types of work can be performed. There are various types of attachments such as blade shape, jaw type ripper, bucket type, radio remote control, snow removal type, winch type, etc.
2. Various types of crawler shoes
There are various types of crawler shoes for wetland work, including standard types, which can be selected according to the application. The cross section of the shoe is triangular and wide. Shoes for snow and rock are also available.
Types of Construction Bulldozers
There are many types of bulldozer blades and rippers.
1. Classification by Blade
- Straight-type
This is a standard type of blade. It can be tilted to the vertical direction when viewed from the side by a hydraulic cylinder, and has a large capacity to push out a large amount of material at one time.
- U-type
This type of bulldozer has a U-shaped blade with both ends bent forward to push out a large amount of earth and sand. This type is used for super-large bulldozers.
- Angle-type
The blade is angled to the left or right in the direction of travel. It is used for one-sided cutting work and heaping and spilling work. In power angle dozers, the blade angle can be changed hydraulically from the operator’s seat.
2. Classification by Ripper
- Multi-shank type
This is a standard 3-jaw ripper. It crushes large rocks. The number of shanks can be changed according to the hardness of the rock.
- Giant-type
Long shanks for deep drilling.
- Parallel link
Equipped with a parallel link mechanism to maintain a constant penetration angle even if the penetration depth is changed.
3. Classification of bulldozers
The standard classification of bulldozers by weight is as follows: small size: 3 to 12 tons, medium size: 13 to 24 tons, large size: 28 to 42 tons, and super large size: 44 tons or more. Another classification by the location where they are used is dry-land bulldozers and wet-land bulldozers. Wetland bulldozers are designed to work in soft ground.
Other Information on Construction Bulldozers
1. Characteristics of Bulldozers in Japan
In Japan, many bulldozers for wetlands can be used at construction sites on soft ground. The ground contact area of the crawler is widened to reduce ground pressure, and a specially shaped shoe is used. It has better lateral sliding characteristics and excellent rolling pressure effect.
2. Qualifications Required
To handle a bulldozer, a qualification is required: to drive and operate a vehicle of 3 tons or more, it is necessary to obtain a national qualification in vehicle-based construction machinery operation skills. The course consists of a classroom lecture and practical skills training at a designated training institute. The content of the course includes the structure and handling of traveling equipment, structure, handling, and working methods of work equipment, driving knowledge, and laws and regulations. Practical skills include driving operation, operation of work equipment, and signaling.
3. Manufacturers of Construction Bulldozers
There are very few manufacturers of bulldozers, with Caterpillar of the U.S. and Komatsu of Japan almost monopolizing the world market. Komatsu has developed radio-controlled bulldozers for use at disaster sites or to improve work efficiency. And in recent years, Komatsu has introduced bulldozers that use GPS satellite positioning systems and 3D CAD design data to assist operators and automatically control blades.
Caterpillar also developed a bulldozer in 2009 that is powered by an engine and driven by an electric motor. This product can be said to be environmentally friendly.