Crane classification, basic mechanism, performance parameters

Lifting Machinery Classification Cranes can be classified into light and small lifting equipment, elevators, cranes, and overhead monorail systems according to different structures. The light and small lifting equipment mainly includes lifting pulleys, spreaders, jacks, manual hoists, electric hoists and ordinary winches. Most of them are small in size, light in weight and easy to use. In addition to electric hoists and winches, the vast majority of human-driven, suitable for work is not heavy occasions. They can be used alone, and some can also be used as crane lifting mechanism. Some light and small lifting equipment have a large lifting capacity. For example, the hydraulic jack has a lifting capacity of 750 tons. The lifts are mainly used for vertical or near-vertical lifting movements and have fixed lifting routes, including elevators, lift tables, mine hoists and hopper elevators. A crane is a multi-acting lifting appliance that vertically lifts and lifts a heavy object horizontally within a certain range. The overhead monorail system has a rigidly formed track that can transport material to various parts of the plant, as well as to the exterior of the plant.

The basic mechanism of the lifting mechanism The various lifting mechanisms have different uses and different structures. However, they all have a lifting mechanism that performs the basic operation of lifting and lowering. Some lifting appliances also have operating mechanisms, luffing mechanisms, slewing mechanisms, or other specialized working mechanisms. The material may be lifted and lowered by a flexible member such as a wire rope or a lifting chain, or may be lifted by a screw or other rigid member.

Lifting machine performance parameters The most important performance parameters that characterize the basic working capacity of lifting appliances are the lifting weight and the working level. 1 weight refers to the maximum weight of a heavy object that is allowed to be lifted under the specified working conditions, that is, the rated weight. In general, cranes with electromagnetic chucks (see lifting suction cups) or grabs should also include the weight of an electromagnetic chuck or grapple. The weight of the boom type crane also includes the weight of the hook group. 2 The working level is a performance parameter that reflects the overall working condition of the crane, and is an important basis for the design and selection of lifting appliances. It is determined by the total number of work cycles and load conditions that the lifting appliance needs to complete during the required use period. The International Organization for Standardization (ISO) stipulates that the lifting machinery work level be divided into 8 levels. China only stipulates that the cranes be divided into 8 levels. The light and small lifting equipment, lifts, and overhead monorail systems have not yet been classified. For cranes with strong regularity and repeatability of operating procedures, such as cranes for loading and unloading ship cargo at docks, stacker cranes for overhead warehouses, and hopper elevators for feeding blast furnaces, the working cycle is also an important parameter. Work cycle refers to the time required to complete a work cycle, which depends on the working speed of the organization and is related to the carrying distance. The above cranes sometimes use productivity as an important parameter, which is usually expressed in terms of the amount of lift performed per hour.