Gate type crane gate crane bridge on both sides by supporting leg on the ground track or foundation of bridge type crane.Orbits along the ground, below but by rail vehicles or other ground vehicles.Rotating lifting device is installed on the door form mounts a boom type of crane.Portal of mount 4 legs 4 "the gate", for rail cars and other vehicles pass.Mostly along the floor or building a door crane orbit, crane loading and unloading operations.Portal is "" glyph of half door crane, crane said one side of its orbit in the ground, on the other side is located in the top of a building above the ground.
It can be divided into three categories by appllication: (1) : a cargo door crane is mainly used for the port and the stocking yard in the open air, grab or hook load and unload.Lifting weight is generally not more than 25 tons, not changing with amplitude.Working speed is higher, so the productivity is often important index.(2) ship gate crane: mainly used in building berth, dock and fitting-out scene, carries on the hull splicing, equipment fitting-out, such as lifting work, with hook as a spreader.Maximum weight of 300 tons, at the time of the large range of weight reduced accordingly.How file hoisting speed, hoisting light lifting speed can be improved.Some work institutions also have micro devices, in order to meet the installation requirements.Door head high, can adapt to the requirement of large hoisting height and large assignments, but the work speed is low, work productivity is not high.(3) building installation with door crane: mainly used in hydropower station dam water, lifting equipment and fabrication, generally with the hook.Lifting weight and speed of work general interfaces between the former two types of crane.It has a good transport installation, hook down deep, can well adapt to the characteristics of temporary work and work on pier.
Door crane hoisting, slewing, luffing and run institutions, three kinds of institutions on the rotating part, before every week period to participate in the work.The rotating part is also equipped with longitudinal tilting one-armed or combination of arm and the driver room.Line agencies, installed at the lower part of the door, in order to adjust the working position of crane with doumen crane (figure 2 [with doumen crane]) also equipped with a telescopic funnel, additional equipment such as belt conveyor, in order to improve the door crane grab when loading and unloading material productivity.In addition to electrical protection device, equipped with lifting weight or crane moment limiter, crane rail safety device.
Door crane is mostly adopt level luffing system.(1) the weight and their center of gravity in the process of the luffing boom system almost no vertical displacement.One of these methods is to rely on additional activities balance weight to balance the luffing boom system changes in the synthesis of center of gravity when it's convenient to make this approach to decorate, work more reliable, also widely used.Another approach is to rely on institutional characteristics of the boom system to ensure that the synthesis of center of gravity when the luffing movement closer to the horizon, no activities balance weight.(2) the lifting weights in luffing process along close to the trajectory of horizontal movement, can adopt compensation method and combination method of boom.Compensation method is automatically by the special ChuSheng system in luffing process and corresponding hoisting rope, to compensate for boom lifting sling caused by vertical displacement.Combination method of boom is relying on the combination of the boom structure features ensure arms end in luffing process close to horizontal direction.Two methods are widely used.