ANIMAL TRAP
A snap trap with a two-stage setting sequence to protect the fingers.
The user revolves the spring-loaded bail and secures it under an L-shaped latch engaging the bait carrier; in this position the trap is set but cannot be sprung, as a rest prevents the bait carrier from moving far enough. The user then grasps the latch by an extension beyond the bail and slides it outward along a slot, arming the trap. The mouse presses the bait carrier downward; the latch slips from its nook and the bail snaps down.
“These requirements have produced rodent traps which require a rather steady hand to set to the end that they will be set in a manner that they can be sprung easily and many people are of the temperament that they find considerable difficulty in properly setting one of these traps.”— William R. McCabe, from the specification
And the world did not beat a path to his door.