ANIMAL-TRAP.
A snap trap that locks itself to protect the setter's fingers.
The operator swings the wire jaw backward against its high-tension springs. The jaw engages a cam on a rear-pivoted latch, which lifts and then depresses the latch's toe beneath a hook on the spring-loaded trigger; the trigger snaps up and locks the latch automatically, without the hands touching it. A mouse stepping on the trigger plate depresses it, releasing the latch toe. The springs drive the jaw forward to strike and clamp the animal against the base.
“The primary object of the invention is to provide a trap of this character with improved means for automatically engaging the jaw as it is being moved to set position and for automatically locking it in set position, to the end that it shall not be necessary to manipulate the trigger or other locking device, thus avoiding the danger of having the fingers snapped by the jaw.”— Samuel Robinson, from the specification
And the world did not beat a path to his door.