Sounds like the clamp bolt or the wedge that it screws into could be threaded, which would explain why it's working itself loose. I would check both of those, and if that is the case you can buy a replacement bolt/wedge pretty cheap from bike shops as it's a common replacement part.
Sounds like the clamp bolt or the wedge that it screws into could be threaded, which would explain why it's working itself loose. I would check both of those, and if that is the case you can buy a replacement bolt/wedge pretty cheap from bike shops as it's a common replacement part.