ES 
EN Bridge crane generally be made up of the trolley, bridge, cart, electric control system.
Trolley
Trolley is a key component of the crane, generally be made up of the hoisting mechanism, operating mechanism and small frame.
A) Lifting mechanism
The hoisting mechanism is the main executive of the crane. In general it is mainly composed of motor, reducer, brake, reel group, wire rope, pulley set, spreader and the compensation shaft and coupling between these parts.
Different cranes and different uses of the lifting mechanism of the different requirements, the main structure also has some changes; general bridge crane hoisting mechanism is generally the most basic composition; for some special requirements of the special crane or its The hoisting mechanism has special requirements, such as the main hoisting mechanism of the casting crane.
In general, the main hoisting mechanism of the casting crane requires two sets of drive devices. When the two sets of drive devices are in the normal operation, the liquid metal containers are lifted at the same time. When one set of two sets of drive devices fails, another set of equipment is required to be lifted A working cycle. Then each drive must have a short-term overload capacity; and if the four rope grab lifting mechanism also has two sets of drive devices, one for the opening and closing agencies, a set of lifting agencies.
The hoisting mechanism is not the same in its form, and its parts are not the same. For example, the general hoisting mechanism and the light structure of the car, with a rotating hook and no lifting hook lifting mechanism. In general, the requirements and arrangement of the hoisting mechanism may vary.
B) Operational organization
Car operating mechanism is the crane’s executive body, which is generally by the motor, reducer, brake, coupling, compensation shaft, active wheels and passive wheels and other components.
The operating mechanism is divided into a centralized drive and a separate drive (including the running mechanism of the cart). The operating mechanism is driven by a set of drive devices, driven by two or more sets of drive devices.
The drive ratio of the operating mechanism (including the large and the car) is the ratio of the number of active wheels and the total number of wheels. If the car running mechanism has eight wheels, of which the number of active wheels two, then we called a quarter drive.
If the motor, brake, reducer are separated, through the coupling, brake wheel and other forms of connection, there are three pieces of integrated three-in-one drive device, a wheel group Bearing box with angular bearing box, the wheel group bearing box also has 45 ° split type, there are also used flange bearing box, etc., with reducer connected with the base, there are three re-use of the reducer type; According to the contract requirements and the use of a reasonable choice of its structural form.
C) Small frame
The small frame is the main bearing structure of the car, which is arranged on the upper part of the lifting mechanism and operating mechanism. The frame consists of a number of beams. The small frame must have good rigidity and strength to ensure the normal operation of each body, the general frame of the stiffness control L / 2000 (L for the calculation of the distance between the beam support point).
Bridge
The bridge is the most important load-bearing component of the universal crane. It is usually composed of the main girder, the end girder, the car track, the tower, the cable, the railing and the cab structure. Generally by the main beam and end beams using box-like structure.
gantry crane metal structure in addition to the above components are beams, legs, under the beam and so on.
