They are linked by chains: every cart has a coin-operated lock accepting a chain and a chain for the next cart to connect.

https://upload.wikimedia.org/wikipedia/commons/thumb/b/b1/Pf...

Put a coin in the drawer and close it, the chain of the next cart pops out the back and you can take it. On return, you push the chain back in, the drawer pops open and you get your coin back.

Store employees just occasionally balance cart numbers between the corrals, if there's multiple.

No, it's much simpler than you are probably imagining. The cart locks to the one in front using a short chain with a plug between a device attached to the handlebars of each cart. It comes out of the back of one and locks into the front of the other.

Put a coin(or any coin shaped object) in and a simple mechanic latch releases the chain, plug it back in and you get your coin back.

Theres a coin activated mechanical lock on each cart, carts are stacked and chained together by these locks.

To get one, you insert a coin (or a plastic token - these are usually given away as freebies by many companies if not the stores themselves) and that unlocks the chain.

It's not about the money, no one earns anything from this. It's about putting something that you own (can be worthless, the emotion counts) in the cart which you can only possibly get back if you return the cart to any number of bays on the parking lot or next to the entrance.

The handle of each cart has a lock and a small chain. Initially the carts are stacked inside each other, with the chain locked in the lock of the next cart. If you put a coin (or other round flat object like the handle of a key) into the lock you can remove the chain and use the cart. When you return the cart you insert the chain from another cart and get your coin back. It's a very simple and robust mechanism.

You insert a coin into a slot in the cart, and a chained key releases the cart from the next cart it's chained to. When you want your coin back, you return it to the line of carts, stack it and then insert the key from the next cart into yours. Your coin is released and the store doesn't have to pay someone to collect them.

It's similar to the "SmartECart" luggage cart kiosks you may have seen at airports. Sliding a cart in locks it in place on a set of rails, depositing the money releases a mechanical catch on the end, allowing you to pull one cart out.

You might be thinking of this system used by Ikea. https://youtu.be/JRXdlgBe8wg

https://en.wikipedia.org/wiki/Smarte_Carte looks like it might be the airport system you have in mind.

The usual European shopping cart system works with a coin deposit, chains and mechanical locks on each cart, as described in several other comments.

not sure why 10 people needed to answer your question lol