The prototype of the crane
The prototype of the crane
Ancient Chinese irrigation farmland with orange is the prototype of the jib cranes.
In the 14th century, maneuvering and animal-driven rotary jib-type cranes were introduced in Western Europe.In the early nineteenth century, the emergence of the bridge crane; crane important wear parts such as shafts, gears and spreader, etc. began to use metal materials, and began to use hydraulic drive. In the late 19th century, hydraulically driven cranes were gradually replaced by steam driven cranes.
In the 1920 s, the electrical industry and the rapid development of the internal combustion engine industry,Various types of cranes, which are driven by a motor or an internal combustion engine, are basically formed.
Crane mainly includes hoisting mechanism, operating mechanism, luffing mechanism, slewing mechanism and metal structure.Hoisting mechanism is the basic working mechanism of the crane, mostly by the hanging system and winch, but also through the hydraulic system lifting heavy objects.The operating mechanism is used to move the weight horizontally in the vertical direction or to adjust the work position of the crane. Generally, it is composed of motor, retarder, brake and wheel.The luffing mechanism is only provided on the jib type crane,When the jib crane the amplitude decreases, the amplitude increases when the bow down, sub-equilibrium amplitude and non-equilibrium amplitude of two.
Rotating mechanism for turning the boom, is driven by the device and slewing support device. Metal structure is the skeleton of the crane, the main carriers such as bridge, boom and mast can be box-shaped structure or truss structure, but also for the web structure, and some can be used as a support beam.