The bulk of the mechanism is made out of 1/2 inch pvc tubing. The spring is a section I cut from a old fashion screen door spring. this spring is secured by forcing it into the top of the pvc tubing. The bottom jaw is made out of a wood dowel whittled down so that it would fit snugly into the spring. The trigger is made from a 1 inch dowel. I drilled a 3/4 inch hole through the dowel and then carved the dowel down to prevent finger pinching and cut a grove to prevent pressure points on the fingers. 14 gauge wire secures the trigger to the bottom jaw.
The mechanism works great. I think I'll probably use this design for all my new rod puppets.