Not sure how to post a picture, but I cut curved ends on 4x4's to match the wheels and then a 1" hole through the middle that I have a pipe clamp through (tow on each side, top/bottom). They have an easy screw handle, and after loosening a kick with my heal frees them. I have noticed I need to re-tighten a couple times if I put them on while the tires are hot.
It did reduce my stock of woodworking clamps by two, but still having >100 I'm OK. The two used on the trailer chocks are the two that are used the most often.