I obtained a tripod awhile ago, but have only recently begun to use it. My problem with it is that the camera top is, as the title says, loose and floppy. The base legs, and such adjustments, work perfectly fine. It's just that I cannot seem to prevent the top component from flailing over at a minimal bump of force. How can I resolve this?

This is the part in question. Here are photos of the entire tripod at a few different angles. (I've no clue what code to use to downsize and/or hide the images, sorry.)