TRIGGER FOR A SPRING-TYPE MOUSETRAP
Snaps only after the mouse has finished eating the bait.
The bait is impaled on the longer fingers of two wire holders, which fixes their orientation so that their shorter fingers hold the trigger lever in place. The mouse eats the bait off the fingers. As the bait is consumed, the holders lose their fixed orientation and their fingers slip off the lever. The lever trips and the spring-driven clamp swings onto the mouse, which is still at the bait.
“It has often been discovered that baited mousetraps have had the bait eaten off by mice and that the trap failed to trip even though the bait had been consumed by a mouse.”— Russell G. Poff, from the specification
And the world did not beat a path to his door.