Spring-loaded camming device

[captnbunny]

For my final term project I am to build a spring-loaded camming device, like those used in rock climbing, that could be fitted inside a horizontal crack and hold as much weight as possible. The device, which must weigh less than 500g and be less than 20cm long in any dimension, will be tested in two ways:

Static test, in which weights are gradually added to the device
Dynamic test, in which weights are attached to the device, raised, and then dropped

The crack itself is 5cm wide, 30 cm deep and 40cm long, and the device must only contact the inside walls of the crack.

This project is due in about three weeks and no one in my class seems to have any idea how to do this. Could someone please tell me where to begin?

Thanks in advance.

 

[Pythagorean]

well, you're designing something that already exists, so why not start with researching existing camming devices?

 

[captnbunny]

What materials should I use?