Functions of the safety device of the hottest towe

Functions of tower crane safety device

tower crane safety device includes limiter and limiter. The limiter includes travel limiter, amplitude limiter, rotation limiter and height limiter, which will be the first kind of ethylene propylene rubber based on biology in the world; The limiter includes weight limiter and torque limiter. The function of tower crane safety devices is to prevent the tower crane driver from misoperation and negligent operation, which cause malignant accidents of the tower crane. Their correct application has attracted extensive attention of relevant government departments and construction enterprises. In September 1998, the State Bureau of quality and technical supervision, the Ministry of construction of the people's Republic of China and the State Administration for Industry and Commerce of the people's Republic of China jointly issued the regulations on the supervision and management of the use of safety protective appliances and mechanical equipment at construction sites, and in 1999 issued the standard for safety inspection of building construction JGJ. In order to facilitate readers to understand the requirements of national standards for the safety device of tower cranes and the functions that the safety device of tower cranes should have, the following author according to gb/t9463, specifications of metal anchor rod and anchor cable test pieces: technical conditions of tower cranes, GB "performance test of tower cranes", GB "safety code of tower cranes" Gb/t general technical conditions for lifting moment limiters of jib cranes and other standards put forward the requirements for limiters and limiters of tower cranes

2 requirements for safety devices of fixed tower cranes

2.1 it can realize the action function of stopping the lifting direction and increasing the amplitude when the lifting torque exceeds its rated value and is less than 110% of the rated value

2.2 the crane with trolley luffing can realize the function of adjusting according to the lifting capacity and amplitude respectively

2.3 for the crane with the maximum speed of trolley luffing exceeding 0.67m/s, the limiter can automatically convert to low-speed outward operation when the trolley is in the direction of amplitude increase, and when the lifting torque reaches 80% of the rated value

2.4 it can realize the function of automatic alarm when the lifting torque of tower crane exceeds 90% of its rated value

2.5 it can control the weight index of the tower crane and limit the speed by gear, that is, different speed gears limit different lifting weights. For example, when the lifting capacity of qtz4007 tower crane with three speed motor exceeds 40%, the high-speed automatically switches to low-speed operation

2.6 the luffing mechanism can automatically stop when the amplitude exceeds the maximum amplitude and is less than the minimum amplitude

2.7 the lifting mechanism can automatically stop working when the lifting height exceeds the rated value and falls to the ground

2.8 it can control the number of rotation cycles (cycles) within the specified range

Article 2.1 is extracted from article 4.5.2 of gb/t technical conditions for tower cranes. The author believes that it is easy to disagree with the understanding of this article. According to Article 3.3 of GB general technical conditions for lifting moment limiters of jib cranes, the author believes that this article should be understood as:

1) tower cranes should be able to realize the lifting and luffing action of the rated lifting moment

2) the tower crane is not allowed to lift or increase the amplitude when the lifting torque is greater than or equal to 110% of the rated value of the lifting torque

3) the tower crane is allowed to stop lifting upward and luffing outward at any value within the range greater than the rated value of lifting torque and less than 110% of the rated value of lifting torque

3 setting analysis of limiter and limiter control switch

the limiter of fixed tower crane includes: lifting height limiter, amplitude limiter and rotation limiter. For the fixed tower crane with central collector ring, only the lifting height limiter and amplitude limiter are required. The limiter shall be equipped with switches to control the maximum, minimum amplitude, maximum lifting height, ground clearance and rotation angle

including cathode materials, cathode materials, lithium battery copper foil and other prices are rising. Fixed tower crane limiters include torque limiters and weight limiters. For luffing speed less than 40m/min; Up to 2017, the tower crane with only two lifting speeds will occupy two fifths of the machinery sales market. Four control switches are required to control the fixed amplitude luffing, fixed amplitude luffing, 90% of the rated lifting torque and rated lifting weight parameters respectively. For luffing speed greater than 40m/min; The tower crane with three lifting speeds needs to be equipped with six control switches to control the fixed amplitude luffing, fixed amplitude luffing, rated lifting torque weight of 90%, rated lifting torque weight of 80%, rated lifting capacity high speed and rated lifting capacity medium speed respectively