Maintenance of overspeed and broken rope protectio

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Elevator overspeed and broken rope protection device maintenance

elevator is a vertical means of transportation carrying people, and safe operation must be put in the first place. In order to ensure the safe operation of the elevator, the prevention of hazards should be fully considered from the aspects of design, manufacturing, installation and other links, and special safety devices should be set for various possible hazards. The governor safety gear system is a safety device that plays a protective role in the event of overspeed and rope breakage of the elevator. Whether the system can work normally depends not only on the design and manufacturing, but also on the introduction of policies at different levels of the market and industrial environment for daily maintenance

article 9.9.1 of the national standard GB7588 1997 "Specification for elevator manufacturing and installation" stipulates that the action speed of the speed governor operating the car safety gear device should occur at 115% of the rated speed. But it should be less than: a) 0.8m/s for instantaneous safety gear devices other than non detachable roller type; b) 1.00m/s for non detachable roller safety gear; c) 1.50M/s for progressive safety gear device with rated speed less than or equal to 1.00m/S; d) For progressive safety gear device with rated speed greater than 1.00m/s, it is 1.25 + 0.25m/s. For elevators with a rated speed of more than 1.00m/s, it is recommended to check the operating speed according to the above upper limit value. Article 9.9.4 stipulates that when the governor acts, the tension of the governor rope shall not be less than the larger of the following two: a) 300N, b) twice the force required for the safety gear device to function. Pull the connecting rod arm of the safety gear with 300N lifting force, the whole mechanism can act flexibly, and the linkage switch can also act at the same time. After releasing the pull arm, the mechanism should be able to be quickly reassembled. After assembly, the main technical parameters of the tensile testing machine should be retested, but the linkage switch should not be reset. With the movement of the connecting rod mechanism, the wedge should be able to slide flexibly in the Tong seat. Under normal circumstances, the clearance between the wedge and the working surface on the guide rail side should be uniform and within 2 ~ 3mm

the above contents fully discuss the necessary conditions and basic requirements for the action of the governor safety gear system. However, in the inspection of the governor safety gear, it was found that due to poor maintenance of some elevators, the safety device could not meet the normal working requirements at all. The main problems are as follows: (1) the rated action speed of the speed governor spring changes due to its long-term fatigue stress state of repeated expansion and contraction; (2) The rotating parts are short of oil for a long time, and the resistance increases, resulting in the inflexible action of the centrifugal swing part; (3) Due to the change and extension of the steel wire rope itself, the tensioning device touches the ground, causing insufficient tension of the steel wire rope and slipping; (4) The driving part of the connecting rod pull arm of the safety gear is lack of oil and rusted, resulting in the lifting force greatly exceeding 300N; (5) The distance between the end of the active lever and the linkage switch of the safety gear is too large. When the pull arm is lifted, the switch cannot act at the same time; (6) The clearance between the wedge and the working surface on the guide rail side is too large. When the connecting rod is lifted, the wedge cannot jam the guide rail; (7) There is too much oil in the wedge, and the wedge cannot be reset after loosening the pull arm, resulting in damage to the guide rail compared with the more traditional composite and metal based solutions. The existence of these problems not only makes the system a decoration, but also easy to cause paralysis, and the potential harm is greater. Therefore, it is necessary to strengthen the maintenance of speed governor and safety gear to prevent major accidents. Specifically, the following two points should be done well:

(1) the speed governor should be checked frequently. Calcium base lubricating oil should be squeezed once a week for the rotating shaft pin, tensioner axle and shaft sleeve. The tension of the tensioning device should be consistent. The rotating shaft pin should be oiled once a week and cleaned once a year. The lead seal should not be removed. The centrifugal swing device should be cleaned and oiled regularly to maintain flexible action. When the rope extension of the speed governor exceeds the specified range, the rope shall be shortened. The operating speed of the speed governor shall be verified by relevant departments every two years to ensure that it is within the range specified in the national standard

(2) the safety gear and connecting rod mechanism should be lubricated with engine oil once a month and tightened at the same time to ensure that the lifting force is quickly transmitted to the safety gear pull rod and does not exceed 300N. Adjust loose springs, screws, pins and other parts. Apply a small amount of Vaseline to the wedge and clamp base once a month. Regularly clean and adjust the wedge block of safety gear, remove the oil deposited inside, and ensure the flexible action of the wedge block

in a word, the safety gear system of speed governor is a very important safety device of elevator. Whether its action is normal or not is not only related to the operation safety of elevator itself, but also related to the safety of human life and property. Therefore, it is necessary for elevator users to strengthen the maintenance of safety devices that show people a new face full of vitality and imagination. At the same time, elevator supervision and inspection institutions must also strengthen the safety management of elevators, especially the inspection and test of elevator safety devices, so as to ensure the safe and efficient operation of elevators

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