I've always thought these clamps are cool for some reason, and I'm also working on a customizable version.
The design is a little tricky though since the circles are all
"unwrapped" when in the neutral position.
Anyway, have fun with my scan if you want. Works with about 3/4 to 5/8 tubing. Or you could also try scaling it and see what happens.
Scanned and vectorized. You'll need to (optionally scale) the svg and extrude it to approx 1/4 inch thick.
To use it, insert it over some tubing and pinch closed with pliers. To open, slide the jaws to the side.