Saw this on diginfonews a while back, it's a neat concept.
There's one thing that might be problematic with this design. The nut has a threaded c-shape insert. Due to the threading, when it is in the "wedged" position, it doesn't just have to close the gap between the tips of the "C" (let's suppose that this deformation is in the horizontal plane), it also has to deform vertically due to the threading.
This vertical plus horizontal deformation must be either harsh on the material, require a relatively small amount of "wedge" (reducing the usefulness), or have a complex initial shape in anticipation of this type of deformation.
There's one thing that might be problematic with this design. The nut has a threaded c-shape insert. Due to the threading, when it is in the "wedged" position, it doesn't just have to close the gap between the tips of the "C" (let's suppose that this deformation is in the horizontal plane), it also has to deform vertically due to the threading.
This vertical plus horizontal deformation must be either harsh on the material, require a relatively small amount of "wedge" (reducing the usefulness), or have a complex initial shape in anticipation of this type of deformation.