Discussion on the locking safety of the landing do

2022-08-18
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Discussion on the locking safety of elevator landing doors

elevators, as vertical transportation of materials, are widely used in industrial and mining enterprises, which basically constitute industrial systems such as high-end metal materials, advanced chemical new materials, electronic information materials and new inorganic non-metallic materials. This year, several falling accidents at the landing door of elevators have occurred for the sudden value of plates. From the results of accident investigation and analysis, these accidents are mainly caused by the improper management of the user unit, the undocumented operation of the operators or the illegal maintenance of the maintenance personnel. However, it can not be ignored that the defects in the design, manufacture and installation of the door lock mechanism are also the main reasons for these accidents. Therefore, in order to prevent the occurrence of such accidents, in addition to strengthening the use and management of lifts and improving the quality of maintenance and users, it is also crucial to ensure the reliability of door locks. Therefore, this paper will discuss how to improve the safety of landing door locking

I. several safety problems caused by falling from height at the landing door

on January 19, 2005, a worker of a company in Quanzhou was pinched to death while moving things out in the traction cargo elevator. This accident was mainly caused by the maintenance personnel shorting the door lock contact. On January 29 of the same year, a female worker who had just entered the factory in a company in Fuzhou, when carrying goods, stepped into the shaft without observing whether the lift car was on the floor when opening the landing door, and fell to death. The hammer body and handle were firmly fixed on the tensile testing machine. The main reason was that the mechanical locking device of the third landing door failed, so that the landing door could be opened when the lift car was not on the third landing. On January 25, a worker of a company in Jiangyin Industrial Zone of Fuqing was pinched to death while taking the traction cargo elevator. The cause of the accident was also that the door lock was damaged and the contact was shorted. The causes of these accidents are mainly caused by the damage or unreliability (high failure rate) of the door lock in the daily use process, which is short circuited by the maintenance personnel. However, why the failure rate of the door lock mechanism is high, and the phenomenon that it is not easy to unlock or cannot be locked often occurs in the use process. After on-site investigation and theoretical analysis, it is inseparable from the defects of the door lock mechanism

1. Type of door lock mechanism

as we all know, the landing door locking device of the elevator mainly has two types: the landing door locking device of power unlocking and the landing door locking device of manual unlocking (as shown in Figure 1, unmodified). The floor door locking device of power unlocking can be divided into the unlocking mechanism that uses the motor to drive the door knife to drive the door lock opening roller through the transmission device (referred to as motor unlocking) and the unlocking mechanism that uses the electromagnet to drive the door knife to drive the door lock opening roller (referred to as electromagnet unlocking). The landing door locking device for manual unlocking, that is, when the lift car is in the unlocking area of the landing station, the operator presses the door opening knob, pulls the unlocking lever through the steel wire rope, lifts the locking hook, and pulls the landing door by hand to open the landing door. Most of the landing door locking devices in use before 2005 are manually unlocked. The defects of the landing door locking device that is manually unlocked are analyzed below

1. Safety contact switch 2. Door lock stop 3. Adjusting bolt 4. Roller

5. Compression spring 6. (triangle lock) cable 7. Adjusting bolt 8. (drive contact) locking hook 9. (door buckle) cable 10. Compression spring 11. Stop

2. Working principle of manually unlocking landing door locking device

when the driver rotates the triangle lock, Through cable 6 (or when the car is at this landing, push the roller 4 through the door knife to drive the door lock block 2 to rotate, so that the gap a between the block 2 and the top of the hook 8 is increased. At the same time, press the door buckle at the landing door to drive the cable 9 to rotate the hook 8. At present, the hook head is lifted to disengage from the block 11, and the landing door can be opened. When the car is not at this landing or the triangle lock is not rotated, the door lock block 2 will prevent the hook 8 from rotating, and the block 11 restricts the movement of the hook 8, and the landing door cannot be opened.

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