Crane is a kind of hoisting machinery, which is in cyclical and intermittent motion. Crane can move weights vertically and horizontally in a certain scope. An operating cycle of Crane include lifting the items by banging device, moving to the designated place horizontally and lowering the item, reversing the movement to return the banging device in situ for the next cycle.
 
It is mainly used for lifting and moving items; and if it is equipped with appropriate spreader, bulk material and liquid material can also be lifted and moved. Crane's work is characterized by intermittent movement, that is to say corresponding mechanisms controlling the action of fetching, moving and unloading work by turns in one working cycle. Mechanisms are often in the working condition of starting, braking and operating in positive and negative direction.
 
Usually, hoisting machinery is composed of hoisting mechanism that makes items up and down movement, operation mechanism that makes hoisting machinery move, traction mechanism, revolving mechanism that move the items horizontally, metal mechanism, power plant, operation control and necessary auxiliary devices.
 
Hoisting machinery, due to the difference in structure and properties, can be generally divided into four categories - series lifting equipment,

gantry crane, Jib crane, cable crane.
 
Series lifting equipment, including lifting jack, lifting tackle and winch,  characterized by handiness, compact structure and simple actions, which can only make weights up-and-down movement.
 
Gantry crane, composed of hoisting mechanism, big and small operating mechanism, characterizes that it can make the weights on the hook or other fetching devices move vertically or horizontally. It can lift and move the weights in certain area with cooperative actions among these mechanisms. Gantry crane, including goliath crane, loading bridge and overhead crane for metallurgic plants, is widely use for loading and unloading items in Workshop, warehouse, open storage area.
 
Jib crane is similar to Gantry crane, which composed of hoisting mechanism, revolving mechanism and traction mechanism. With the cooperation of these mechanisms, it can lift and move weights in a certain round area. Jib crane is usually installed on vehicles or other types of transportations; and then jib rotary crane will be formed, for example, truck crane, railway crane and wheel crane.
 
Cable crane, also called elevator, mainly refer to crane with hoist, which characterize that the weights or fetching device can only be raised and fallen along the guide rail. Though elevator only has one lifting mechanism, there are many other accessory devices in the elevator. It includes the elevator, goods elevator and ship lift, etc.
 
Given that there are many types of cranes, companies should choose them according to their practical situations.