The Knoble in .45 caliber was one of the pistols in the US pistol trials of 1907. Unfortunately for Mr. Knoble, his pistol was deemed to crude for the Ordnance Board to consider even test firing, and it was dropped from the trial like a hot potato.
Knoble only made a handful of pistols in total, and this is an example in .30 Luger caliber which is essentially identical in function to the .45 trials gun. it uses a short recoil, toggle locking system to operate, and is definitely a pretty crude piece of workmanship. Cool to take a closer look at, though!