Draglines are a fairly old type of excavator, and they are still in the steam age, when wire rope excavators were invented shortly after they were invented. It is characterized by a long boom and no stick. The position and inclination of the bucket is controlled by the hoisting rope and the pulling rope. The bucket cuts the soil by gravity, which is suitable for excavating relatively soft materials below the stopping surface.
The basic structural layout of draglines includes tracked chassis, turntables, slewing mechanisms, booms, various hoists, and buckets. A slewing support is installed between the turntable and the chassis. The turntable can be rotated 360 degrees to the left and right. On the turntable, hoisting hoisting, luffing hoisting and traction hoisting are installed. Hoisting hoisting controls the bucket's lifting and Landing, luffing hoist controls the elevation angle of the boom by retracting the wire rope, and traction hoist controls the drag and throw of the bucket by retracting the wire rope. The boom of the dragline is composed of a basic arm and a middle boom section, and the middle boom section can be appropriately connected according to the needs of the operation. The digging characteristics of a dragline shovel are: "backward and downward, cutting by gravity." Its digging radius and digging depth are large, and it can excavate one or two grades of soil below the stopping surface. During work, it uses inertial force to throw the bucket out and digs farther. However, it is not as flexible and accurate as a backhoe, and is suitable for excavating large and deep foundation pits or underwater soil.