How can we ensure that only one person can pass through the turnstile at the station at a time?

The third type is the somewhat old-fashioned manual three-stick turnstile we are going to talk about today. It can pass a person every time it rotates 120°.

First do a simple disassembly. The maintenance man controlled the circuit in a \”non-locking\” state, that is, it is not locked, so you can see the three sticks spinning like a windmill. ..What is used here is an electromagnetic attraction structure for control.

Change the angle, and control the electromagnetic attraction atIn the \”locked\” state, the stick can stop rotating.

Ratchet mechanism

First of all, let’s introduce what a ratchet is. Literally, it means that there are many “thorns” on the wheel, that is, there are raised teeth on the outer or inner edge of the wheel, which are pushed in one direction by the pawls. Rotate. For example, the following is\”External ratchet mechanism\”, the thing inserted into the tooth slot is called a pawl. Unless the pawl is pulled open, the ratchet can only operate in one direction.

The nylon ties we often use to tie things are actually a variation of the ratchet structure, except that the external teeth are changed intoInternal teeth. This kind of tie gets tighter and tighter in one direction. Usually it is over-tied if you are not careful… When I was a kid, I tied it on my hand and found that I couldn\’t untie it. I was really panicked…

Then let’s take a look at how the ratchet drives the stick to rotate. I\’ll switch to a turnstile demonstration where I can see the internal structure clearly. After you swipe your card, the electronic component recognizes that \”passage is allowed\” and controls the electromagnetic suction device to unlock. You manually pull the stick through the turnstile, and wait for the stick to rotate After passing 120°, it will automatically lock and the ratchet will stop rotating…so the machine can only release one person at a time.

Change the appearance of another ratchet, It remains unchanged and achieves the same gate rotation function

As for the assembly of the mechanical structure, I found a video from a major manufacturer. Just layer by layer

The final assembly is the linkage structure in the picture below.

There are many examples of ratchets being used for lag control in life. One of the more common ones is the revolving fence door that is used at the entrance of many residential communities. This kind of door can also be used in both directions to provide a path in and out of the community. Different, the pawls on different sides are unlocked, and only one person can enter at a time.

Looking at a top view, it still rotates 120° every time It will get stuck in a fixed position

I found an explosion diagram of an animation demonstration. Pay attention to the fact that the two double-layer ratchets are fixed together in opposite directions.

Here is a real picture. The double-layer ratchets are stacked in opposite directions. This is to allow the ratchets to only rotate one position at a time instead of constantly turning in one direction.

Of course, the revolving door at the entrance of this community still uses electromagnetic attraction to control the pawl.

Proofreading: Cast + Jiang Xiaosang

Original title: How is the rotating stick door of the station gate controlled to allow only one person to enter at a time? | Interesting manufacturing

Source: Interesting Manufacturing

Editor: C&C