Overhead cranes are hoisting equipment that is horizontally placed over workshops, warehouses and stockyards for material hoisting. Because its two ends sit on tall concrete columns or metal supports, it is shaped like a bridge. The bridge of the bridge crane runs longitudinally along the track laid on the elevated on both sides, which can make full use of the space under the bridge to lift materials without being hindered by ground equipment. It is the most widely used and the largest number of hoisting machinery.
  A bridge-type crane with a bridge running on an elevated track, also known as a crane. The bridge frame of the bridge crane runs longitudinally along the tracks laid on the elevated bridges on both sides, and the hoisting trolley runs laterally along the tracks laid on the bridge frame, forming a rectangular working range, which can make full use of the space under the bridge frame to lift materials without Obstructed by ground equipment. This kind of crane is widely used in indoor and outdoor warehouses, factories, docks and open storage yards.
ordinary bridge
  Overhead cranes generally consist of bridge frames (also known as carts). It is composed of hoisting mechanism, trolley, cart moving mechanism, control room, trolley conductive device (auxiliary sliding line), crane main power conductive device (main sliding line) and other parts.
bridge
  The bridge frame is the basic component of the bridge crane, which consists of the main beam, end beam, walking platform and other parts. The main beam spans over the span, and there are structural forms such as box-shaped, split-frame, web, round tube and so on. Both ends of the main beam are connected with end beams, and a walking platform is installed on the outside of the two main beams with safety railings. A cart moving mechanism is installed on the platform on one side of the cab, and a device for supplying power to the electrical equipment of the trolley, that is, an auxiliary sliding line, is installed on the other side of the platform. A guide rail is laid above the main beam for the trolley to move. The entire bridge crane moves on the guide rail along the length of the workshop under the drag of the cart moving mechanism.
Cart moving mechanism
  The cart moving mechanism is composed of cart drag motor, transmission shaft, reducer, wheels and brakes, etc. There are two driving modes: centralized driving and separate driving.
Car moving mechanism
  The trolley is placed on the bridge rail and can move along the width of the workshop. The trolley is mainly welded by steel plates, and consists of a trolley frame, a trolley moving mechanism and a lifting mechanism on it.
The trolley moving mechanism is composed of trolley motor, brake, coupling, reducer and wheels. The trolley motor drives the trolley driving wheel through the reducer, and drags the trolley to move along the guide rail. Because the trolley driving wheel is close to each other, it is driven by a motor.
  There are two transmission forms of the trolley moving mechanism: one is that the reduction box is in the middle of the two driving wheels; the other is that the reduction box is installed on one side of the trolley. The reduction box is installed in the middle of the two driving wheels, so that the torque borne by the drive shaft is relatively uniform; the reduction box is installed on one side of the trolley, which makes installation and maintenance more convenient.
Lifting mechanism
The hoisting mechanism consists of a hoisting motor, a reducer, a reel, and a brake. The hoisting motor is connected with the reducer through the coupling and the braking wheel. The output shaft of the reducer is connected with the reel on which the wire rope is wound. The other end of the wire rope is equipped with a hook. When the reel rotates, the hook will roll with the wire rope. Winding or unwinding on the barrel rises or falls. For cranes with a lifting capacity of 15t and above, there are two sets of lifting mechanisms, namely the main hook and the auxiliary hook.
It can be seen from this that the heavy object moves up and down on the hook with the rotation of the reel; as the trolley moves left and right in the width direction of the workshop, and can move forward and backward with the cart in the length direction of the workshop. In this way, the movement of the heavy objects in the vertical, horizontal and vertical directions can be realized, and the heavy objects can be moved to any position in the workshop to complete the lifting and transportation task.
control room
  The cab is the pod that controls the crane, also known as the cab. There are large and small car moving mechanism control devices, lifting mechanism control devices and crane protection devices in the operating room.
The control room is generally fixed at one end of the main beam, and a few are installed under the trolley to move with the trolley. Above the control room, there is a hatch leading to the walking platform for maintenance personnel to get up and down when overhauling the mechanical and electrical equipment of the large and small cars.
There are three types of motion of overhead cranes:
(1) The bridge crane is driven by the cart motor to move longitudinally back and forth along the two sides of the factory workshop.
(2) The trolley and the hoisting mechanism on the main beam of the cart are driven by the trolley motor to move laterally left and right along the main beam track of the bridge.
(3) The lifting motor (main hook, auxiliary hook) drives the heavy object to do vertical lifting.