Trends and research status of cranes

( 1 ) large-scale and specialization

As the industry continues to expand the scale of production , increasing productivity , and product loading and unloading of materials during production gradually increased the proportion of costs , prompting a large or growing demand for high-speed crane . From the weight of growing, increasingly high operating speed , and reliability of energy consumption and higher requirements . Crane has become automated production processes is an important part . Crane not only easy to operate , easy to maintain, and better security , higher reliability , excellent durability requirements , trouble-free nature , maintenance and use of economy. Currently the world's largest floating crane lifting capacity of 6500t, the largest crawler crane lifting capacity of 3000t, the largest crane on weight of 1200t, the maximum operating speed of container shore crane trolley reached 350m/min, stacker cranes the maximum operating speed is 240m/min, garbage crane lifting speed up to 100m/min.

Industrial production and diversity of user requirements , so special crane market continues to expand, varieties are constantly updated to meet the unique features of special needs , to play the best effect. Such as metallurgy , nuclear power , paper, waste disposal special cranes , explosion-proof, anti-corrosion, insulation crane and rail , ship , container cranes function increasing continuously improve performance, adaptability stronger than ever . Demag Cranes company developed a dedicated aircraft maintenance , opened the market in the international market . This crane is mounted on the housing structure, span , lifting height and large , you can cross over , high precision parking . How to install telescopic catheter , connected with aircraft maintenance platforms following the lifting trolley , and 360 -degree rotation . By displacement carts and car , lift and rotate the catheter can repair platform to reach any part of the aircraft , aircraft maintenance and repair carried out extremely quickly and conveniently.

( 2 ) a combination of modularity and

Instead of the traditional method of modular machine design , the basic functions of the crane on the same member , parts and components made ​​of a variety of purposes , with the same standard coupling elements and interchangeable modules , each with different combinations of modules , the formation of different types and sizes of cranes. Improved crane , just for a few modules. Design of new cranes , simply choose different modules re- mix. Single and small batch production can switch from the crane has a considerable volume module production to achieve high efficiency of specialized production , the production organization can also be changed product management module management . Achieve improved overall performance , reduce manufacturing costs and improve the general level , the composition of many varieties with less number of parts specifications , multi- standard products to fully meet user needs.

Currently , Germany, Britain, France, the United States and Japan have adopted the famous Crane Crane modular design, and achieved remarkable results. German Demag standard cranes series switch modular design , the design than the one-piece design expenses decreased 12% to 45% decrease in production costs , economic benefits are substantial . Demag KBK company has also developed a flexible modular overhead crane , crane from cold-rolled steel rail type combination , the crane can be arbitrarily arranged along a line running production process , may have cross road, turn, cross- over , variable gauge . All parts can achieve mass production , according to the different needs of users and the specific material handling course in a short time will mix and match various components Serve. This crane combination is very good, easy to operate, can make full use of space , low running costs. There are manual and automatic forms, but also the composition of the suspension system , single-girder overhead cranes, double girder overhead cranes, jib cranes, gantry cranes and lightweight manual stacker cranes , and even the composition of large automated material handling systems.

( 3 ) Light and diversification

There are considerable quantities of cranes are used in the general case, the work is not very heavy. Such cranes large quantities , versatile, considering the overall efficiency , requiring a crane to minimize the appearance height, simplify the structure, reducing the weight and wheel pressure , but also make the whole building height decrease , structural lightweight , lower cost . So there will be a faster development of electric hoist bridge crane and beam cranes, and most small and medium tonnage to replace general purpose bridge crane . Demag in Germany after decades of development and innovation , has formed a lightweight modular standard crane series. From the weight of 1-63 tons , working level A1-A7, the entire series from the I-shaped and box -type single girder , single girder suspension box , triangle -shaped single varieties of small trunk and box girder double girder and other components. Main beam and end beam lifting trolley layout phase and a variety of types , can be suitable for different buildings and different lifting height requirements. Each crane specifications according to user needs has three single-speed and two-speed for any of the three choices, you can also choose inverter . There are ways to manipulate the door to move on their own ground flashlight , flashlight door with the car moving , flashlight door fixed, wireless remote control, fixed cab , the cab with the car moving , moving on their own cab and other seven choices. Powered carts and car cable car , there are two ways conductivity , DVS system . So many options, through different combinations, with hundreds of cranes, fully meet the needs of different users . Another biggest advantage of this crane is lighter , light weight, light wheel pressure , dimensions height is small, can greatly reduce the construction cost of the plant buildings , but also to reduce the cost of running power and run the crane . Compared with generic products, from the weight of 10t, span 22.5m, Universal double girder overhead crane weight is 24t, crane rail surface height above 1876mm, crane width 5980mm; Demag Cranes weight only 8.7t, light weight 176 % , more than the height of the crane rail surface 920mm, reducing the 104% crane width 2980mm, dimension reduction of 100%.

( 4 ) automation and intelligent

Updating and development of cranes , depends largely on the improvement of electrical transmission and control . The mechanical technology and electronic technology, advanced computer technology, microelectronics , power electronics, fiber optic technology, hydraulic technology , fuzzy control technique applied to the mechanical drive and control system, the crane automation and intelligent. A new generation of large-scale and efficient crane electrical control device has been developed for all-electronic digital control system . Mainly driven by the digital control unit , programmable logic controllers , fault diagnosis and data management systems, digital manipulation of a given testing equipment. Fuzzy control variable voltage variable frequency speed control , radio data communication , fault diagnosis surveillance, anti-sway spreader , the laser lifting objects to find the center of gravity , near-field inductive anti-collision technology , fieldbus, carrier communication and control , non-contact power supply and three-dimensional bar code technology will be widely applied. So that the crane has a higher flexibility to fit multiple batches of small quantities of flexible production model to improve single integrated automation level. Focuses on the development of high-performance microprocessor core electrical transmission device, so the crane has excellent speed and static and dynamic characteristics , automatic control can be operated automatically display automatic protection and automatic detection and recording , crane operation, special occasions the long-distance remote control , so as to meet the needs of automated production . Such as using a laser device to find the center of gravity position lifting objects , equipped with ultrasonic sensors to guide the device automatically extract extract grab goods on the device . Spreader automatic anti-sway system can run speed 200m/min , the case of acceleration 0.5m2 / s soon make lifting objects swing amplitude is reduced to a few millimeters. Crane precision positioning can be achieved by a magnetic field transducer or laser . Near-field sensing system installed on the crane , the crane can avoid collisions between each other . Crane also installed on the computer self-diagnostic monitoring system that can provide most of the routine maintenance check the contents , such as gearbox oil temperature, oil level, wheel bearing temperature , crane loads, stresses and vibration , the life of the brake linings and temperature conditions.

( 5 ) New technology and practical

Structure of thin-walled steel profiles and profiled to reduce stitching seam structure , improve fatigue resistance . Using a variety of high-strength low-alloy steel of new materials to improve the carrying capacity, improve stress conditions , to reduce weight and increase the aesthetic appearance. Overhead crane bridge structure type mostly used box -shaped four- beam structure, the main beam and side beams of bolt connection , easy to transport and install .

In terms of institutions to further the development of new transmission parts , simplified organization . "Triple play" run organization is the world's light , mainstream institutions intermediate crane operation , the motor , speed reducer and brake into one, with a compact, lightweight and beautiful , easy accessibility , simple adjustment , smooth operation , supporting a large range etc., has been widely used abroad to various crane operating agencies . To enable small and medium- tonnage crane trolley structure as simple as possible , while reducing the size of the crane height decreases wheel pressure abroad has been widely adopted as an electric hoist lifting mechanism . To reduce weight , improve the bearing capacity, improve manufacturing conditions , increase product yield, as far as possible to weld parts on behalf of the cast , such as reducer shell, roll Jane, pulleys and so welded structures. Hardened reducer gears are used to reduce weight , reduce the volume and improve the bearing capacity and increase service life. Hydraulic disc brakes putter range of applications is also growing . In addition, the agencies are used to high- speed development of the electric motor , thereby reducing the number of motor base , reduce weight and reduced dimensions, and can be equipped with a braking torque small brake.

In terms of well developed electronic control performance, low cost , high reliability speed control system and electric control system , the development of semi-automatic and fully automatic manipulation. Electromechanical integration solution using technology to improve performance and reliability , increase the crane functions. The future will be more emphasis on crane safety, the development of new safety devices . Attention to the working conditions of drivers , application ergonomically designed cab , drivers reduce labor intensity . Germany in recent years to solve the crane hook anti- sway control , developed a fuzzy logic control technology with fuzzy neural information and technology to find the best time to start accelerating , the driver would have experienced anti-sway actual operation data input system , to achieve optimal Control . Fuzzy control method can determine the implementation of control commands work automatically and will blur the amount of people subjectively quantified by digitizing the fuzzy set , and then use the computer to achieve the same ease as the skilled driver operation , achieved greater efficiency and safety. Fuzzy Control as a new control method has been noticeable.