Elevators are vertical vehicles that carry people, and safety must be given top priority. In order to ensure the safe operation of the elevator, all aspects such as design, manufacture and installation must fully consider preventing the occurrence of danger, and set up special complete devices for various possible dangers. The speed limiter safety gear system is a safety device that protects the elevator in the event of overspeed and rope breakage. Whether the system can work normally depends not only on the design and manufacture, but more importantly on the daily maintenance.
Article 9.9.1 of the national standard GB7588-1997 "Code for Elevator Manufacturing and Installation" stipulates that the operating speed of the speed limiter for operating the safety gear device of the car should occur at 115% of the rated speed. However, it shall be less than: a) 0.8m/s for momentary safety gear units other than non-detachable roller types; b) 1.00m/s for non-detachable roller type safety gear units; c) for rated speed 1.50m/s for progressive safety gear devices less than or equal to 1.00m/s; d) 1.25+0.25/v for progressive safety gear devices with rated speeds greater than 1.00m/s. For elevators whose rated speed exceeds 1.00m/s, it is recommended to check according to the operating speed of the above upper limit. Article 9.9.4 stipulates that when the speed limiter is in action, the tension force of the speed limiter 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 work.
Pull the safety gear link arm with 300N pulling force, the whole mechanism is flexible, and the linkage switch can also act at the same time. After releasing the pull arm, the mechanism should be able to recover quickly, but the linkage switch should not be reset. With the movement of the linkage mechanism, the wedge should be able to slide flexibly in the clamp seat. Under normal circumstances, the gap between the wedge block and the working surface of the guide rail side should be uniform and should be within 2-3mm.
The above content fully discusses the necessary conditions and basic requirements for the operation of the speed limiter safety gear system. However, in the inspection of the speed limiter safety gear, it is found that some elevators are poorly maintained, so that the safety device cannot meet the normal working requirements at all. , the main problems are as follows: (1) The speed limiter spring is in a state of repeated expansion and contraction for a long time, so the speed of its setting action changes; (2) The rotating parts are short of oil for a long time, and the resistance increases, which makes the centrifugal swing part inflexible; (3) Due to the change and extension of the wire rope itself, the tensioning device touches the ground, causing insufficient wire rope tension and slipping; (4) The transmission part of the connecting rod arm of the safety gear lacks oil and corrodes, causing the lifting force to exceed 300N. ;(5) The distance between the end of the active lever and the safety gear linkage switch is too large, when the pull arm is lifted, the switch cannot act at the same time; (6) The clearance between the wedge block and the working surface of the guide rail side is too large, and the wedge block is stuck when the connecting rod is lifted. (7) There is too much oil in the wedge block, and the wedge block cannot be reset after loosening the pull arm, resulting in damage to the guide rail. The existence of these problems not only makes the system a decoration, but also easily causes psychological paralysis, and the potential harm is even greater. Therefore, it is necessary to strengthen the maintenance of the speed limiter and safety gear to prevent the occurrence of major accidents. Specifically, the following two points should be done:
(1) The speed limiter should be checked frequently. Rotary shaft pins, tensioner axles and bushings should be squeezed with calcium-based lubricating oil once a week. The tension of the tensioning device should be consistent, the rotating shaft pin should be oiled once a week and cleaned once a year. When the elongation of the rope of the speed governor exceeds the specified range, the rope shall be shortened. Every 2 years, the speed limiter action speed shall be checked by the relevant departments to ensure that its action speed is within the range specified by the national standard.
(2) The safety gear and connecting rod mechanism should be lubricated with oil once a month, and tightened at the same time to ensure that the pulling force is quickly transmitted to the safety gear rod, and does not exceed 300N. Adjust loose springs, screws, pins and other parts. Apply a small amount of Vaseline once a month to the wedges and clamps. Regularly clean and adjust the safety clamp wedge to remove the oil deposited inside to ensure the flexible action of the clamp block.
In short. The speed limiter safety gear system is a very important safety device in the elevator. Whether its action is normal or not is not only related to the operation safety of the elevator itself, but also to the safety of people's lives and property. Therefore, it is necessary for elevator users to strengthen the maintenance of this safety device. At the same time, elevator supervision and inspection agencies must also strengthen the safety management of elevators, especially the inspection and testing of elevator safety devices, so as to ensure safe and efficient operation of elevators.
