Make an unqualified bolt, and your head will bleed on the spot, and you will be horrified to see it!

网站编辑:浙江天开实业有限公司 │ 发布时间:2023-05-10 

In just five minutes, the short video "Luo Si"

It is said that the embankment of thousands of miles collapses in the ant's nest. Don't look at the small size of the screw (relative to the equipment where it is located). If it really starts a fire, the temper is not small. If it is light, it will lead to unplanned downtime and reduce production efficiency, and if it is heavy, it will cause a catastrophe and cause huge losses.

Accidents that require screws to back the pot abound in history。

Case one

On June 10, 1990, during the flight of British Airways flight 5390, a piece of the windshield of the cabin suddenly flew off, and the upper body of the captain was sucked out of the aircraft. Fortunately, with the efforts of the co-pilot, it landed safely at Southampton Airport.

Case two

During the lunch rush in September 2009, a ceiling fan in the cafeteria of Guangzhou University of Technology suddenly fell from the ceiling. The rapidly rotating electric fan injured and scratched two students. The cause of the accident was that the screws fixing the electric fan fell.

Case three

On December 14, 2010, the escalator No. 5 of Guomao Station on Shenzhen Metro Line 1 suddenly reversed from the upstream, causing 25 passengers to be injured.The cause of the accident was the loosening of the fixing bolts of the escalator mainframe, one of which was cut off, causing the mainframe support to shift, and the driving chain to detach from the sprocket. Under the action of the weight of the passengers, the ascending escalator slid down.


Case four

At 16:45 on June 29, 2010, the capsule of the “Space Trek” entertainment facility in OCT, eastern Shenzhen, collapsed, causing 6 deaths and 10 injuries. The cause of the accident was a loose bolt.

Case five

At 18:35 on November 6, 2017, a female worker of Shenzhen Weihongzhi Hardware Products Co., Ltd. was knocked down by another punch that suddenly dumped next to her while operating the punch. She died after being rescued. The reason was that there were no anchor bolts installed on the base of the collapsed punch machine. There should be 2 bolts on the side, but only 1 was installed, and it loosened during long-term operation, and eventually the center of gravity unbalanced and caused the collapse.


There are still many bloody lessons

Every time I see such an accident

We who eat melons will always be angry and courageous.

Isn't it just a matter of screwing a screw?

What do maintenance workers do?

Why does such an accident always happen?

If you go head-to-head, no matter how tight the bolts are, they will loosen.

Let's take a look at the working principle of bolts

They use the circular rotation and friction of the bevel of the object

Gradually tighten the parts of the artifact step by step

Therefore, whether the bolts are fastened or not is to a large extent

It depends on whether it is tightly engaged with the threaded area of the fixture

However, is the bolt really tightened once and for all?

The teeth are hard, it's okay to touch the tongue

It will only ring if you knock on a hard object, and it will break and loosen if you knock hard.

Whether it is a bolt, nut, or a fixed material

Most of the surfaces are hard and will not accommodate each other.

Most of the working state of the machinery is repetitive movement

Some movements are accompanied by severe vibration and shock

Under frequent vibration

The thread that was originally tightly clamped

It will produce tiny gaps and even deformation


Accumulated to a certain extent

It will cause subtle displacement and spin

So the bolts that were originally tightened slowly loosened.

Therefore, sometimes you can't rely on maintenance workers

Machinery must be maintained regularly to avoid accidents

Prevent sudden shutdown due to loose bolts

Sometimes the cost of downtime is also very expensive, okay?


Loose rail bolts, potential derailment factors

The properties of bolt shake M are also used for testing

To detect the fasteners under certain frequency and amplitude conditions

Self-locking performance under applied transverse dynamic load (anti-loosening performance)

This is the Juncker vibration test


Comparison of Juncker vibration tests on different bolts

Servo automatic tightening device is used during the test

Automatically tighten the bolt/nut according to the set initial clamping force or torque

After that, the vibration environment is simulated according to the set test parameters and conditions

Analyze fasteners through recorded technical indicators

Changes in axial force, loosening angle, amplitude, horizontal thrust, etc.

Which is the strongest nut washer?Below is a video of the Junker vibration test of 13 kinds of nut washers.

Video data

Obviously it looks very reliable

I actually shook it a few times and it loosened.

Most of the nuts and washers in the video are still relatively fast.

Oh yeah, it's so scary to think about it

Isn't there no screw in the world that won't loosen?