What Are These Clip Things Called?

[joggerjayne]

Does anyone know what these things are called? I will try to describe them.

You see them on trucks.
They hold down the tarpaulin covers.
They stick out. The tarpaulin has holes in with metal rings.
You put the rings over these sticky out things.
Then you pull them upwards, and they sort of drop down, and lock into place, so that they secure the tarpaulin against the side of the truck.

I've also seen them securing the back of a pick up truck.
You put the back bit up, and the holes in the back bit go over these sticky out things.
Then you lift them up, and they drop down and lock into place, to keep the back of the truck from falling open.

I want some of these things, to secure a tarpaulin at home. But I don't know what they are called (or even if they have a name).
Any ideas??

[teacake44]

:0)