Derrick Crane refers to the fixed installation of cranes, generally used in port. Derrick Crane, also known as pull rods or rods, are a simple lifting device. This kind of crane has the characteristics of simple fabrication, convenient installation and demolition, heavy weight, and limited construction site. In particular, hoisting large components and the lack of large-scale lifting machinery, this kind of lifting equipment more obvious its advantages. But this kind of cranes need to set more cable wind rope, moving difficult. In addition, its lifting radius is small, the flexibility is poor. Therefore, Derrick Crane are generally used for heavier components, more concentrated hoisting works, narrow construction sites, and lack of other suitable large hoisting machinery.
Derrick Crane according to structural characteristics, can be divided into the following three forms:
(i) One-legged pull rod
Single-foot pull rod is divided into: wooden sole-foot pull rod, steel pipe single foot pull rod and lattice-type single foot pull rod.
The sole-foot pulling rod is composed of pulling rod, hoisting pulley group, hoist, cable wind rope and anchorage. The number of cable wind ropes is generally $number root, at least not less than 4. The pulling lever of lifting is not greater than 10 ° angle. The movement of the sole pull lever is carried out by the bottom of the trailer. (Erection of one-legged pull rod)
The wooden foot pulls the pole to lift the weight within the 100kN, the lifting height generally is the 8~15m, the steel tube pulls the pole to lift the weight to reach the 300kN, the hoisting height is within 20m; the lattice type alone pulls the pole to lift the weight to reach the 1000kN, the lifting height may reach the 70m.
(ii) Human character pulling lever
The herringbone puller is usually made of two round wood or two steel pipe with wire rope lashing or iron piece hinged. Its advantage is that the lateral stability is better than the single foot pulling rod, the number of cables used in the cable is small, but the activity range of the component is smaller. The bottom of the miter rod is provided with a lever or pulling rope to balance the horizontal thrust, and the two-bar angle is usually about 30°. The person pulls the pole to lift the rod to tilt forward, in the rear has two cable wind rope. In order to ensure the stability of the bottom of the lifting rod, a guide pulley is mounted at the bottom of a pulling rod, and the lifting cable is connected to the hoist by means of another wire rope attached to the anchorage.
Round Mook word puller, starting weight 40~140kn, pulling rod long 6~13m, round wood small head diameter 200~340mm; steel pipe herringbone pull rod, starting weight 100kN, pulling rod length 20m, steel pipe od 273mm, wall thickness 10mm; The weight of 200kN, the length of the rod, the wall-thickness 7m.
(iii) Cantilever puller
The cantilever puller is a lifting arm in the middle or 2/3 height of a single foot. It is characterized by high lifting height and large lifting radius, and the swinging angle of the crane arm is also large. However, the crane has a small lifting capacity and is used for hoisting of lightweight components. The lifting arm can also be mounted on the derrick and become a Derrick pull rod.