In 1918, Captain Rupert Hughes of the U.S. Army submitted a patent application for a specialized automatic-opening trench knife of his own design, the "Hughes Trench Knife". This was a curious device consisting of a folding spring-loaded knife blade attached to a handle which fastened to the back of the hand and was secured by a leather strap, leaving the palm and fingers free for grasping other objects. Pressing a button on the handle automatically extended the blade into an open and locked position, allowing the knife to be used as a stabbing weapon. The "Hughes Trench Knife" was evaluated as a potential military arm by a panel of U.S. Army officers from the American Expeditionary Force (AEF) in June 1918. After testing the board found the "Hughes" design to be of no value, and it was never adopted. Hughes went on to patent his automatic trench knife in 1919, though it appears to have never interested any civilian manufacturers.