furniture
There is a component which I've seen most often in car seat headrests which acts as a ratchet. You can pull the headrest forward and it will lock at steps until you pull it too far, and it will reset all the way back.
It's sort of a ratchet mechanism which resets after a certain range of motion.
I don't know what it's called. I've tried "resetting ratchet", "resetting step lock", and many other queries.
Do you know the name of this component?
That would be the cam lock nut and cam screw fastener.
They are commonly found in DIY assembly products sold by various retailers including IKEA. According to a recent post I've read IKEA may be looking to replace this fastener type in its products, but I haven't seen any changes yet so probably best not to hold your breath. However, there are alternatives to this fastener such as TorpedoCSIS.
The "Big Blue Store" calls it a Double 90-degree angle.
Best Answer
I've found them called "Headrest Hinge" on Amazon and Ebay.
https://www.amazon.com/s?k=headrest+hinge