Tower cranes composition, characteristics, and must have a device which

Tower crane A crane is a tower boom mounted on the upper rotary towering cranes, working space, mainly for housing construction in the vertical and horizontal transport of materials, as well as the installation of building components .That its composition, characteristics, must have a device such knowledge, we all know? If even these do not understand, then it is not a good understanding of towerbridge gantry cranes, so here we come to Intro knowledge.1 compositionTower crane mainly by the metal structure, work organization, and the electrical system which consists of three parts, metal structures, including the tower, boom and base, working bodies including hoisting, luffing, slewing and walking four parts, electrical systems, including motors, controllers, power distribution cabinets, connecting lines, signal and lighting devices.2 Features(1) tower crane boom in the form of horizontal and lever type two, long horizontal boom, but the boom weight greater than horizontal strut-type smooth, but the weight is smaller.(2) from the weight of the crane with the magnitude of change is, from the weight of the product with the magnitude of the load torque.(3) lifting height of tower cranes large, rotating and walking large inertial mass, so the need for good speed performance, light load lifting mechanism to quickly reload slow.(4) In addition to using resistance speed tower cranes, but also can be used eddy current brake, FM, pole, SCR and mechanical and electrical joint, etc. for speed.(5) In order to ensure safety, tower crane has a good safety devices, including some of the stopper, and travel limit switch, walkways and railings.(6) cab comfort, easy operation, good vision, and has excellent communications equipment.3 The device must haveTower crane must have a starting weight limiter, torque limiter, height limiter, stroke limiter, amplitude limiter and so on.Lifting limiter - also called overload limiter, is a way for non-occurrence of crane overload safety device running. When lifting more than nominal weight, the device can automatically cut off the power lifting mechanism, so that theoverhead bridge crane stop or an alarm, it has two types of mechanical and electronic.Torque limiter - Cranes if overweight, there is the danger of tipping over, so there is a torque limiter that protection devices. If the suspended matter beyond its corresponding weight, the circuit will be cut off, the lift can not be, so as to ensure the stability of the crane, which has mechanical, electronic, and three types of compound.Height limiter - also called hook height limiter, are generally mounted on the boom head role is to make the sliding hook does not exceed the limit position.Stroke limiter - to prevent or limit the Steel crane crash occurred within a certain range driving, usually installed inside the active trolley.Amplitude limiter - also called amplitude or amplitude limit indicator. When the amplitude, the pointer indicates the various amplitudes under the nominal weight, when the upper and lower arm runs to two extreme positions, the pressure limit switch, cut off the main control circuit, resulting amplitude motor stop, so as to limit the role of .