SELF-SETTING RODENT TRAP
Can be set with one hand, sparing the fingers of the other.
The operator presses a thumb rest on the actuating member, which spreads the spring-loaded piercing arms into open position. As the member descends, a cross-bar guides a latching lever until its end snaps into a port in the trip plate, holding the trap set. A gopher pushing against the trip plate tilts it away from the latching lever, disengaging the latch. The springs then drive the piercing arms closed on the gopher.
“Slipping of either hand may cause a partially set trap to suddenly close with resultant serious injury to one or both of the hands.”— George B. Wilken, from the specification
And the world did not beat a path to his door.