Market status of cranes
In October 2011, the overall sales volume of China's construction machinery industry did not change. Among them, sales of excavators dropped by 29.92% compared with the same period last year, and sales of bulldozers dropped by 21.34% compared with the same period last year. In 2011, under the influence of national macroeconomic regulation and control, the credit crunch policy caused some construction projects to slow down and some of the projects that were originally planned to start postponed. At the same time, consumers were affected by the credit crunch policy, and the cost of purchasing machinery reduced, resulting in lower demand for construction machinery. Although the construction machinery market is facing severe challenges, China's economic growth momentum is still strong. In the coming period, China's construction machinery industry is still in a period of rapid development, especially in the field of crawler crane industry. The national development and Reform Commission issued the guidance catalogue of industrial structure adjustment (2011 Edition) clearly pointed out that 400 ton and above crawler cranes are selected as "encouraging products" as new industries, and the prospects of crawler cranes are promising. In the first three quarters of 2011, China's heavy truck industry sold 712 thousand vehicles. Heavy duty card
Use and maintenance of electric hoist
1. electric hoists newly installed or dismantled and installed should be tested first and then several times. But do not turn on the electricity before the installation is completed. 2. normal use should be carried out at a rated load of 125%, lifting about 100 mm from the ground, 10 minutes of static load test to check whether it is normal. 3. the dynamic load test is carried out with the rated load and weight for repeated lifting and moving tests. After the test, check whether the mechanical transmission parts, the electrical parts and the connecting parts are normal and reliable. 4. in use, it is absolutely prohibited to use in an environment that is not allowed, and exceed the rated load and the rated closing times per hour (120 times). 5. during installation, commissioning and maintenance, it is necessary to strictly check whether the limit device is flexible and reliable. When the hook is raised to * * * extreme position, the distance between the hook shell and the drum shell must be greater than 50mm (10t, 16t, 20t must be greater than 120mm). When the hook is lowered to the lower limit, the wire rope safety circle on the drum should be ensured, and the effective safety circle must be placed.
Cautions for electric hoists
(1) check A. before use. No obstacle or floater should be found in the range of operator's walking, sight line and heavy load. B. manual control buttons should be accurate and sensitive to move up and down, and the motor and reducer should have no abnormal noise. C. brakes should be sensitive and reliable. D. electric hoist should have no foreign body on the running track. E. upper and lower limit operators should be accurate and sensitive. The f. hook nut must be firmly fastened. G. hooks should be flexible in horizontal and vertical directions. H. hook pulley should be flexibly rotated. The I. wire rope should have no obvious cracks, arranged neatly on the reel, and has no signs of disengaging pulley grooves, twisting, buckling, etc., and is well lubricated. There is no abnormal phenomenon in J. lifting AIDS. K. electric hoist working environment temperature is - 25 ~ +40 degrees L. electric hoist is not suitable for corrosive gas or relative humidity greater than 85% of the place, can not replace explosion-proof gourds, it is not suitable for lifting molten metal or toxic, flammable and explosive materials. (
Shipbuilding gantry crane
A crane used in the manufacturing of ships and docks, its mission is to transfer all parts (bars, sections, steel plates, etc.) needed to manufacture the hull from the ground conveyance to the manufacturing site. This transportation work must be able to complete the task very quickly in a long journey. Therefore, the decision of the crane number is based on the principle that the foundation area of the whole dock can be reached, and the cranes are not interfering with each other. This kind of crane has been widely used in the past, and now it is also used in small shipyards. The existing fixed position gantry crane is a tower shaped rotary crane with fixed supports, and the sports car runs on the lower edge of the horizontal extension arm. Since the crane is built many times around the dock, its radius of rotation is determined by its ability to work in the entire shipbuilding area. Door shaped, across the track laid along the dock, to transport parts to the hull. The span of the door is 6 meters. Such cranes are sometimes supported by rotatable struts, sometimes with fixed struts.
Structural characteristics of metallurgical electric hoist
Structural characteristics (1) this series of products is made up of several parts which can be separately disassembled. It is mainly composed of four parts, one is the lifting mechanism, the second is the running mechanism, the three is the control device, four is the second brake device, the use, maintenance and inspection are very convenient, and it can shorten the maintenance period. (2) the motor adopts YZD series conical rotor three-phase asynchronous motor, and protects the motor. Class IP44, motor insulation grade H grade, motor conical brake as support brake; lifting mechanism added safety brake; (3) high temperature insulation protection function is set up under electric hoist, effectively avoiding direct heat radiation; (4) steel wire rope adopts steel core steel wire rope, and has high temperature resistance characteristic; (5) lifting mechanism set overload overload * * * device, when lifting weight reaches When the rated load is 95%, the overload alarm signal is sent out. When the lifting weight reaches 105% of the rated load, the lifting control loop is disconnected, the lifting contactor is released, and the motor loses power and stops rotating; (6) the lifting mechanism achieves an ascending limit.
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