ANIMAL-TRAP
Once closed on a leg, the jaws cannot be reopened.
Two spring-driven toothed jaws are held open by a toggle of two links, each carrying half of the pan. An animal steps on either pan section; the toggle collapses and the jaws snap shut on its leg. As the jaws close, an abutment on a locking arm pivots a dog into a gripping position within its eye. Any attempt to spread the jaws jams the dog against the arm, so the jaws cannot separate.
“My invention relates to an improvement in traps for capturing wild animals, and has for an object the provision, in a trap of this kind, of a locking device for preventing the opening of the trap jaws after they have closed upon the foot or leg of an animal, thereby eliminating the possibility of the release of the animal due to separation of the jaws.”— Albert M. Ahern, from the specification
And the world did not beat a path to his door.