How does a mousetrap work?

BassMaster

I know this may sound like a stupid question but I am the WORST when it comes to any of these mechanisms.

How does a mousetrap work? I tried searching this on the Internet but they just say that it is 'spring-loaded'. What does that mean? And most sites simply say that a mousetrap is a device for catching mice, while some others assume that on already knows what it is.

If someone can give me a reasonably detailed explanation of its mechanism, that would be helpful. Thanks!

berkeman

Here you go. Be advised that there are some dead mice in the pictures....

http://en.wikipedia.org/wiki/Mousetrap

BassMaster

I already read that and here's what I'm confused about:

"It is a simple device with a heavily springloaded bar and a trip to release it."

What is a heavily springloaded bar and a trip?

berkeman

Fair enough. The object of the basic mousetrap is to get the mouse/rat to stick its head in a position where it can get hit hard with something (like a metal bar which has been pulled back against a strong spring), and then the mouse sets off the release for the bar hold-back mechanism by trying to get a piece of food on the release mechanism.

The picture of the mouse at wiki in the first photo shows how the bar has swung from one end of the wood block to the other, and broken the mouse's neck by hitting it hard at the mouse's end.

It's similar to the "Figure-4" traps that we used to make back when I was a kid. In these kinds of traps, you need to store a lot of energy, and then have a hair-trigger release mechanism that lets that energy go (to close a bar hard on a mouse, or in the case of the Figure-4 trap, to release a heavy box cage that falls on the prey).

BassMaster

Okay, I KNOW what a mousetrap is used for. I also know that the hammer slams down on the side of the bait and - most of the time - kills the mouse. What I'm still confused about, though, is the actual mechanism. How does stepping on the area of the bait cause the spring to release? And why, when the spring releases, does the hammer flip?

berkeman

Have you ever seen one? They're only a few cents each at the hardware store, and seeing one work live in front of you will probably make it a lot easier to understand. Just use a stick or something to see how little pressure it takes to set it off.

Here's a nice picture from google images:

http://matcmadison.edu/ald/ILS/pix/mousetrap.jpg

In the loaded position like it shows, the copper bar that goes over the spring is fixed at the far end of the board, and free to slip out of the little hook thing on the cheese lever arm. As the mouse pushes down slightly on the cheese end of that arm, that raises the other end of the arm (or tilts it slightly or does something else....), which angles the little hook thing back just slightly and the low-friction release lets go. The copper bar flips back and to the left, and the "heavily spring loaded bar" flips from back to front.

berkeman

BTW, there are some really humerous shots at google images if you google mousetrap. Like the little guy wearing a helmet as he sneaks up on the cheese, or the computer mouse caught in a trap... LOL.

berkeman

Dah, dah-dah-dah, dah, dah-dah-dah....

http://usera.imagecave.com/auction/other/mousetrap.JPG

BassMaster

I think you' ve explained it the best you can, and although I can say that I'm starting to understand the mechanism... it would be a LOT better if I see it in action.

Thanks for your help. I'll buy one and see how it works.