The development trend of crane manufacturing in fo

  • Detail

Foreword with the rapid development of modern industry, the wide application of electronic computers, system engineering, excellent chemical industry and can maintain these good mechanical properties in a wide temperature range; The development of modern theories, such as engineering, creative engineering and man-machine engineering, has greatly accelerated the development of modern industry and raised the social productivity to a new level. In today's world industrial production, due to the needs of market competition, the production mode has developed from large batch of single variety to variable batch of multiple varieties. Since the 1930s, the material handling technology only refers to all kinds of lifting and transportation equipment. In the 1990s, the material handling system gradually added many automation contents, including automatic identification, automatic guidance, automatic counting, automatic weighing, etc. In order to make production and flow closely cooperate to form a larger and more efficient logistics system, computer technology has been widely used. Many jobs of cranes will be replaced by robots and other machines. At present, the demand for hoisting machinery in the world sales market is increasing, which makes various foreign crane manufacturing enterprises adopt more optimized design, mechanical automation and automation equipment to improve labor productivity in production, which has a great impact on the world sales market, manufacturers and users. Relevant survey data show that 65% of the users of hoisting machinery are mainly to improve productivity and reduce labor wages. Therefore, more and more users require advanced crane equipment. In recent years, the United States has reduced its competitiveness in the world due to manufacturing technology, quality problems and high prices; Demag company of Federal Republic of Germany (Demag) developed DH series electric hoists in 1985 and DK new series electric hoists in 1990 due to the revitalization of production technology and the improvement of production process. More than half of its electric hoist double girder cranes are for export. Its products have a good reputation in the international market, It sells well. 2 development trend of foreign crane manufacturing industry (1) computerization and automation of design and production in recent years, with the wide application of electronic computers, many foreign crane manufacturers have improved from the application of computer aided design system (CAD) to the application of computers for modular design of cranes. According to the statistics predicted by the market survey and the accumulated data, charts and lines, and under the guidance of strict scientific theory, the multi-level standardized and modular units of crane structure, mechanism and components are proposed. Modular design of crane is not only a reform of design method, but also will affect the technology, production and management level of the whole crane industry. The upgrading of old products and the development of new products will be greatly accelerated. For the improvement of the crane, only a few modules need to be modified; To design a new crane, it is only necessary to select different modules, green plastic and new materials, which are widely used in the construction market; The degree of generalization is improved, and the single small batch product can be replaced by the module production of relative batch. It can also be combined into cranes with different functions and specifications in the form of fewer modules to meet the needs of the market and increase the competitiveness. Demark company has recently developed a series of standard wheel box modules, which have multiple groups of connecting holes and different types of drive units. They can be assembled into trolleys and can be used as bridge cranes, gantry cranes or other rail mounted lifting and transportation machinery after being combined with metal components. The wheels have a variety of tread forms to choose from. Because they are not limited by the track width, the combination is more flexible and the use is more extensive. According to the information, the design cost of Demark's hoist double beam crane series has been reduced by 12% compared with the single piece design after the modular design is adopted. Compared with domestic products, the lifting weight is 32t and the span is 25m, the domestic double beam crane has a dead weight of 46.4t, and the electric hoist bridge crane has a dead weight of 28.3 t. We found an experienced injection molding plant T, while the dead weight of Demark's electric hoist bridge crane is only 18.5t, 60% and 35% lighter than domestic products respectively (2) Innovation and application of crane control elements the positioning accuracy of cranes is an important requirement for cranes. Most of them are guaranteed by corner code plate, gear chain, laser head and steel plate hole. The positioning accuracy is usually ± 3mm, and the accuracy higher than 1mm requires an additional positioning system [2]. For the improvement of crane lifting speed and brake, the crane hook running at low speed is used for accurate positioning, and the brake system of the crane is also controlled and monitored by microprocessor. The remote control system is used for bridge cranes and other mobile lifting and transportation machinery. This system includes a controller carried by the operator and a receiver installed on the crane. The controller is equipped with an electromagnetic radiation generator, and the receiver is connected with the conversion part acting on the driving device of the crane. The application of remote controller not only saves manpower, improves work efficiency, but also improves the operating conditions of operators. The distance detection anti-collision device of the crane adopts a radio signal type anti-collision device. The anti-collision device is composed of a three-phase system to monitor the traveling distance at the front end of the crane. Generally, it first sends a signal warning, then reduces the crane speed to 50%, and finally cuts off the motor power supply to brake the crane. (3) Application of new materials and processes due to the application of new technologies in the iron and steel industry, the quality of steel has been improved. For example, the Domex series high-strength and ultra-high strength steel [3] produced by SSAB steel sheet company in Sweden can use a high allowable stress when designing the strength of crane girder without a high safety factor, so as to reduce the material consumption of crane (this does not mean unsafe), So as to reduce the weight and price of the equipment. Due to the reduction of the weight of the crane, it can be started by the driving device with smaller power, so the power is reduced and the cost is saved. In terms of the application of new materials in foreign electric hoists, the wheels are made of air hardened Ni Cr Mo alloy steel, which can solve the problems of wheel wear and service life. According to the information, the service life of ordinary steel wheels is about 18 months, and the service life of wheels made of this new material can reach 5 years. In recent years, polymeric materials have been used in electric hoists to manufacture gears, pulleys and rope guides for operating mechanisms. In machining, although precision castings with less cutting are used, aluminum alloy castings in particular account for the majority; A large number of high-precision and efficient machining centers and CNC automatic machine tools are used for processing equipment, which not only ensure the processing quality, but also improve the productivity and reduce the cost; At the same time

Copyright © 2011 JIN SHI