In daily life, elevators are increasingly indispensable, but we still do not have enough understanding of their temperament. The Xi'an Municipal Bureau of Quality Supervision and the Sanqin Urban Daily have jointly launched the second series of reports on "Xi'an Quality First" to see what misconceptions people have about elevator safety? A professional has given everyone a reassurance: "Let's put it this way, even if all the steel cables are cut during operation, there will not be a sudden descent of the elevator, because just like the handbrake and foot brake of a car, the safety system of the elevator also has' brain brake, leg brake 'and other powerful brakes. Therefore, many tragic elevator accidents are not caused by elevator quality defects, and many people have misconceptions about it."

Misconception 1: "Squeeze and you can get on."

Sometimes the idea that city residents can get on a vertical elevator by squeezing is incorrect and carries extremely high risks. In general, overloading of an elevator causes it to enter self-protection mode and stop running. When the carrying capacity of the elevator approaches the standard load, the elevator will display full load, but it will still continue to operate. If someone in the car makes a significant movement at this time, the elevator will be symmetrical and unbalanced, immediately displaying overweight, and start self-protection to stop operating. If the elevator happens to stop at a high-rise and continue to overload, it is likely to slide down from the high-rise.

Misconception 2 "The elevator lobby door is open but the elevator car is not on that floor"

Elevators are public tools, and the elevator doors directly affect public safety. In terms of design, the elevator hall door is tightly locked by the elevator door lock. Only when the elevator car runs to the opening area can the hall door be opened through the car door knife. Under normal circumstances, the elevator hall door cannot be opened from the outside. Therefore, the main reason for the occurrence of "elevator hall door open but elevator car not on that floor" is: ① The elevator hall door lock malfunctions, and the elevator management personnel operate in violation of regulations, short circuit the elevator door interlocking circuit, and open the elevator door at the same time; ② The elevator management personnel operated the elevator in violation of regulations during maintenance and repair operations, without observing the actual position of the elevator car. They operated the elevator at will, causing passengers to mistakenly believe that the elevator was opening the door, leading to accidents.

Misconception 3: Easy door or ceiling lifting can "escape"

"The elevator has two doors, one is the hall door and the other is the car door. The hall door is equipped with an automatic locking device. Once locked, unless the elevator car is in place and the hall door and the car door overlap, the mechanical lock hook cannot be opened." The relevant person in charge of Xi'an Special Equipment Inspection and Testing Institute explained that in case of emergency, only professional certified personnel can open the hall door by using a dedicated triangular key to open the lock hook.

"The scene of pushing the ceiling upwards and climbing out of the elevator, which is often portrayed in movies, is quite exaggerated. Although there is an emergency exit on the top of the elevator, it needs to be illuminated by the ceiling and a dedicated key to open it." He explained that the top of the elevator car is where maintenance personnel work, surrounded only by work railings. If unfamiliar passengers accidentally board, they not only cannot escape from the shaft, but also are prone to danger and injury.

Misconception 4: "The elevator lobby door opens as soon as you push it"

The elevator hall door, as a necessary passage for taking an elevator, is hung on the door slot by an upper pulley. It is positioned by meshing with the upper positioning wheel and the lower door slider, continuously opening and closing every day. The main source of horizontal stress on the elevator hall door is the gravity of the door itself. Therefore, the hall door is one of the dangerous components of the elevator, and its daily maintenance is very important.

Based on comprehensive analysis, the main reasons for the phenomenon of "elevator hall doors opening as soon as they are pushed" are: ① dust and sand accumulation in the door groove, reducing the depth of engagement of the upper pulley; ② Dust accumulation in the door slot or malfunction of the positioning wheel hinders the opening and closing of the hall door, and maintenance personnel adjust the positioning wheel arbitrarily, causing the pulley on the hall door to not engage; ③ The lower door groove is covered with dust and sand, and the lower sliding block is severely worn. In addition, the lower sliding block is mostly made of resin material, resulting in lower horizontal stress.

Misconception 5: If an elevator malfunctions, it will suddenly fall off

"Vertical elevators have complete protective devices that are maintained normally and will not suddenly fall," he explained. What passengers refer to as "slides" or "slides" are actually mostly illusions. The elevator has at least three security devices. Firstly, elevators all have brakes. In the event of a malfunction or power outage, the brakes will lock the traction motor and stop rotating, ensuring elevator safety. Secondly, upper and lower limit inspection switches and forced deceleration switches are installed in the shaft where the elevator operates. If the elevator reaches the upper and lower limits, the elevator system will enter a forced deceleration and predetermined state. Thirdly, when the speed limiter detects elevator overspeed, it will interlock with the safety caliper brake to lock the elevator car onto the guide rail. It's like two big pliers, once the elevator goes down at high speed, it will hold tightly to prevent falling. In case the elevator quickly descends to the bottom, there is still a buffer at the bottom of the elevator to slow down the impact force when landing.

He introduced that during the operation of the elevator, if there is a small malfunction that causes problems with the elevator floor detection signal, the elevator will enter a protection restart state, automatically stop the corresponding button command, and reset the floor data by returning to the bottom or top floor. Due to the inability of passengers to control the elevator during this process, and the elevator constantly running, it led to people mistakenly thinking it was a "slide" or "slide" of the elevator.

① In elevator design, the two ends of the guide wheel are used to suspend the elevator car and counterweight respectively. The elevator car is lighter than the important one, and the lighter elevator car will not fall when the elevator is unloaded At least five steel wire ropes should be used for hanging elevator cars and counterweights, each composed of multiple strands of steel wire, and each wire rope should be able to withstand more than three times the weight of the elevator car. It is impossible to break them all at once, let alone five at the same time When the operating speed of the elevator exceeds the rated speed, the speed limiter is triggered, the operating power is turned off, and the safety gear is pulled to ensure that the elevator car is stopped on the guide rail. On the other hand, the electrical control circuit also stops running due to overcurrent protection Modern elevator control uses odometer coding to automatically calculate the floor level. When the elevator malfunctions or the safety circuit provides protection, the elevator will automatically run to the base station (first floor).

Based on the above analysis, it is impossible for a normally operating elevator to experience a sudden drop.

Misconception: Why did the display screen on the 6th floor turn from the 8th floor to the 6th floor

"When the elevator malfunctioned, it stumbled and the floor display suddenly changed from the 8th floor to the 6th floor." Many passengers asked, "Did the elevator" fall "from the 6th floor to the 4th floor?"? This is too scary.

In fact, when the elevator is running, the displayed numbers do not correspond very accurately to the floor. He explained that during elevator operation, for the comfort of passengers, it starts, accelerates, decelerates, and stops according to a specific operating curve. Especially for high-speed elevators, when reaching the high-speed stage, the running distance per second exceeds 3 meters, which is greater than one floor height. However, in order to maintain the visual habit of passengers riding the elevator, the displayed floor numbers are stacked at a constant speed, so that passengers do not think that the elevator is suddenly fast or slow. When a malfunction occurs, if the elevator happens to be in the process of starting acceleration or deceleration, there is a certain error between the actual position and the number displayed floor. After the elevator self-protection stops, the floor display will automatically switch to the actual position. This actually leads to passengers mistakenly thinking that the elevator has suddenly dropped several floors. In fact, the elevator stops within the normal braking distance and does not slip.

Misconception 7: Elevator malfunction is an accident

Some citizens may hear abnormal noises while taking the elevator, or the elevator car may shake slightly during operation. In such situations, there is no need to panic. It is reported that various situations may occur during the operation of elevators, such as abnormal noises, shaking, emergency stops, and even trapping people. These are just malfunctions that occur during the operation of the elevator, not elevator accidents. Elevator accidents have a strict and clear definition. According to the relevant laws and regulations on special equipment, elevator accidents can only be classified as elevator accidents if a person is stranded in the elevator car for more than 2 hours or if the elevator causes serious injury, death, or significant property damage.

Misconception 8: Elevator shutdown=elevator accident

During elevator operation, when encountering a sudden power outage and being trapped, most people's reaction is "encountering another elevator accident". But professional analysis suggests that closing the elevator is actually a protective measure for passengers.

Elevator shutdown is actually a normal response to protect passengers when the safety detection system detects abnormalities or faults in the elevator during operation. It is a protective measure for passengers, not an elevator accident. If, in the event of an abnormality, the elevator cannot automatically stop running and close the elevator door, it may actually cause accidental injury.

"When the safety detection system detects abnormalities or malfunctions in the elevator during operation, it automatically takes a normal response to protect passengers, which is why people are shut down." Professionals say that power outage shutdown is essentially due to a sudden power outage, causing the elevator to stop operating without electricity and stop the elevator car in the shaft. The passengers who are locked in the elevator are safe at this time, and maintenance personnel only need to manually turn the car to safely release the passengers.

In case of emergency situations such as elevator trapping, first press the emergency alarm button and contact the duty personnel of the property management company; Secondly, you can call the rescue hotline of the maintenance unit to seek assistance from professionals. Remember, under no circumstances should you engage in dangerous behavior such as climbing the top of the car without authorization or forcefully opening the car door.

Misconception: 9 doors cannot be closed, it's because the elevator is broken

Residents have reported that the elevators in their residential units often get stuck or repeatedly open or close without closing the doors. In fact, this situation is caused by foreign objects embedded in the sliding track of the elevator floor door, or by foreign objects blocking the passage of light in the light curtain area of the elevator door. The elevator door has safety contacts, and as soon as the door is opened, the elevator will stop running. If the elevator car door or hall door is not closed for a certain period of time, the door interlock protection device will be activated, and the elevator will automatically stop. In addition, excessive behavior such as forceful door scraping by someone outside the elevator may also cause the door interlock to disconnect and the elevator to stop running.

Misconception 10: Trapped elevators can cause suffocation

Many passengers are worried that if they get stuck in the elevator due to malfunction, they may suffocate in the narrow elevator without timely rescue. In fact, there are strict regulations in the current national standards for elevators, and only when the ventilation meets the required effect can it be put into the market. In addition, there are gaps at the connection positions of some ventilation devices in the elevator car, such as the connection between the car wall and the car roof, which are generally sufficient for people's breathing needs.