Office chair assembly and question about parts

I have a new office chair. I assembled it. It functions well. However, I have a few questions about it. The questions are relatively simple:

1.) Office chairs have a part which you rotate/turn. It is usually located under the seat. You can see an example of it in the image below (the link is given right below.) The part is indicated inside the red circle. The office chair in the image is a random choice. I was unable to present you with a picture of mine due to various legitimate constraints of life. I assumed that regardless of the office chair, all of this “turn-able/rotate-able” parts do the same job/function.
What does this part do? I have looked at assembly instruction (the “fine” manual, so to say) but there was not information about it.

2.) The seat can be removed from its place with strong force. Is it supposed to be work in this way? Perhaps, I am doing something wrong or incomplete. I do not think that I skipped a step in the assembly process. I re-winded it and tried various combinations. But, still, if I pull the seat upwards with a strong force, it gets removed its place (from the gas lift).

I hope that I have been able to explain the issues clearly enough.

Thank you! :slight_smile:

Probably sets the tension for leaning back.

The dial sets the distance the chair can travel, some people like to be able to rock the base forward so as to be able to slide forward… basically their enormous buttocks lock them into the chair unless they can use the weight of it to go forward.
Its this moving part which breaks or wears out or jams first, therefore after, its locked closed (no rocker) or fully open (won’t stop rocking), or something.
The chair can be dissassembled, but probably its meant to be very very firm and if yours is coming undone easily, its been buggered… (inserted wrongly… get it.)

It is supposed to be difficult, but not impossible, to remove thr seat from the gas spring, so that part may be okay.

On the chairs I’ve repaired by replacing the lift tube, the seat has a slightly tapered socket that matches the end of the lift cylinder. They kind of lock together but can normally be separated with some wiggling of the lift cylinder in the socket.

Replacement cylinders are available on Amazon and they all seem to be interchangeable, so there must be an industry standard for the connection.

Did you sit on it first? A lot of times the seat won’t fully grip onto the piston until there has been significant weight on it. If your weight didn’t get the seat to lock in ask a heavier person to sit in the chair. (Or sit in the chair and get another person to sit on your lap if you’re not bashful) You can also try bouncing a bit on the seat to get it to grip the piston.

Sadly, over here asking another man to sit on your lap whilst one bounces up and down will merely get one a very old-fashioned look. Explaining it was in order to ‘grip the piston’ would merely make it worse.

Thank you so much for the answers! :slight_smile: