Mechanism/Links with Bisecting link? 1

[CPosner]

I've been fiddling with some hand sketches/CAD and going through some references and I'm trying to create a simple mechanism to incorporate around a hand tool. Here's the simplified description:

I have two bars/links pinned together at end points free to rotate around the pin. Now, I want to add another link which will always bisect the two main links. Example, If the angle between the two main links is 175*, then the angle between any one main link and the bisecting link is 87.5*. i.e. always half angle. I've been trying to play with some linkages/levers and possibly some inline gear-reduction but that seems a little clunky. Total range of motion of main links can be something like 120* - 220* angle between the main links.

Any suggestions/references?

Thanks in advance.

 

[EngineerTex]

I started to give a description, but realized that a sketch would be quicker.

Engineering is not the science behind building. It is the science behind not building.

 

[CPosner]

Perfect! I was pretty close to that with some slider, but not quite there. For whatever reason, I was stuck with trying to hold one of the main links fixed and only moving the bisector and other main link.

Thanks!