Design and testing of a nonlinear mechanical advantage demonstration mechanism

A four-bar linkage with prescribed nonlinear mechanical advantage has been synthesized and tested. This tool is intended to in1prove cognition of linkage synthesis theory through interactive demonstrations and has both industrial and educational applications. Industrial applications include use as a proof-of-concept demonstrator and sales device. Academic use will focus on interactive classroom instruction.

In accordance with current educational theory, this tool requires active participation on the part of the student, whether in academia or industry. Interactive methods have repeatedly demonstrated increased effectiveness in developing cognition and retention of technological subjects.

Synthesis of the linkage is based on four-precisian-point Burmester theory. Transformation of the given prescribed mechanical advantage problem into classical synthesis forms, i. e., function generation and body guidance, is necessary during the procedure. The precision points are chosen from the flexion/ extension strength curve of the forearm.

Unlike most strength training equipment, this linkage exploits unused muscular capability by allowing variable resistance. Users are capable of dramatic increases in maximum resistance and efficiency over constant mechanical advantage methods. By allowing the full potential of the muscles to be used, the mechanism achieves a work output per repetition that approaches the maximum theoretical work.