The crane provides a series of operations: capturing a single piece of cargo (or package), lifting and moving it to its destination, lowering and uncoupling cargo lifting and moving lifting device or devices to the starting position for gripping, lifting and moving the next cargo. These operations are alternated in sequence, repeating at certain time intervals (cycles). Therefore, the cranes represent lifting machines of continuous or cyclical operation, in contrast to the action of continuous conveying action (e.g. pipelines) that move loads in a continuous flow.
Jib cranes are divided into several groups, the most numerous of which is a mobile cranes group. Granada Material Handling, also known as GMH, a reputed UK-based business concentrating its efforts on manufacturing, lifting equipment inspection and lifting equipment services, admits the share of sales of general purpose equipment accounts to 63% (statistics are actual for the year of 2012).
Other cranes of jib type (e.g., tower ones) mobile cranes differ in that they have a special device for the escape of an independent movement to the area and are equipped with various types of removable boom equipment that allows the use of cranes on a variety of works and relatively quickly adjustment of their operating parameters. These devices offer high maneuverability within the construction site. Mounting and dismounting of mobile cranes, site preparation for their operation and movement, as well as the relocation of the crane from object to object has become easier, faster and cheaper.
Jib mobile cranes also include truck (the escape device includes a chassis of the car, engine, transmission and control system), pneumatic and tracked (the device comprises a pneumatic wheel or tracked chassis propelled by the power plant, which is located on the rotating part of the crane), as well as special (road type, specially adapted for cranes working conditions) and short base (specially adapted for use on unprepared sites and cramped conditions) chassis machines.
Car boom mobile cranes are used for general purpose lifting and lowering loads and moving them over short distances in the horizontal axis in the production of construction and loading and unloading operations on distributed objects. Truck mounted cranes are distinguished by carrying capacity, type of drive and type of the basic mechanisms of basic truck chassis.
Truck machines typically consist of nonslewing and turning parts, interconnected by supporting-turning device, which transmits the load (load moment, vertical and horizontal forces) of the rotating part of the crane on the immovable part, and also allows the rotation of the rotatable relative nonslewing part.
Undercarriage is represented by truck chassis. The need to host the mechanisms and sites of crane chassis design makes a number of changes: instead of a body on the frame of the car fixed chassis frame features an additionally installed PTO, support bracket arrows, as well as stabilizers or switches with elastic suspensions. Cranes with mechanical drive can additionally feature intermediate gear and cranes with hydraulic drive.