I have been back through lots of patents found 6 for Evans in the 1921 to 1929 range, nothing that comes close to this operating method.
went back through 1913, still could not find anything similar.
Finally found a patent No.681,910 by F. P. Galvin granted on Sept. 30 1901.
This patent shows same teeth on the sides of the top jaw shank, but the spring operated pawls work horizontally not vertically, and the jaws are a shallow v shape.
Bill300d, do you do you have any additional information on the 1913 patent, that you mentioned.