Can anyone suggest an intuitive way of locking a cam lever such as this?
On the backside of the stuff being clamped, add a spacer tube with a spring over it, then a washer and nylok nut. The handle over-centers and is held by the spring.
See PNs 11,53,58,57,16 in the IPB below. The part description is in the link.
The European ball-hitch trailer coupler has a suitable mechanism.
Image source: Edwards Trailers UK.
- The fingers of the hand are inserted in the handle.
- The thumb presses at (1) to opens the safety catch releasing the handle at (3).
- The handle can now be moved up (2).