Fangs and eye mechanism for a muppet style puppet:

Christopher Addolorato

So I'm working on a proof of concept build of a puppet that has a mechanism in the head that can make the eyeballs roll back into the head while also at the same time extending the 2 front fangs. This way The character has a normal look and a possessed by demons look. Here's concept art:

I started designing the head in 3D to 3d print it so its strong and holds the eyes:

And I started to prototype the mouthplate:

Unfortunately I can't hold the teeth down unlessthe mouth is closed. I'd like for there to be a way to keep the teeth in the down position (And also the eyeballs rolled back) until I want him to "change back"

Any ideas on how I can achieve this? Any help would be appreciated.

Chris Ellerby

Very cool character design!

I think having the fang mechanism being a toggle, rather than having to continuously activate it, would help here.

The simplest way to mock that up might be to remove the spring and attach some bendable wire (armature wire or steel wire would work) to the hinge so it holds whatever position you place it in.   Then you could add a finger loop so it could be pulled up, or pushed down easily.

The challenge there is the wire would eventually fatigue, but it will help you see if that style of mechanism would work from a performance perspective.   Then you could look into modifying the hinge or replacing it with an alternative that can easily hold its position.

/Chris

Christopher Addolorato

Thats actually a good idea! Any idea if they make hinges that hold thier position? I'm thinking of using a cable to control it and that could work too.

Chris Ellerby

I have seen some multi-position hinges that are designed to hold set positions, but from what I understand they take a bit of force to snap out of their fixed positions.    Another option would be a torque hinge, which will hold any position it is left in.  Though they may also be difficult to move depending on the model.

You may be able to modify your existing hinge to get it to hold its position.  The ways that come to mind at first, like crimping the knuckles of the hinge so they create friction with the hinge pin, would work well initially but over time would loosen up.  This basically creates a torque hinge.  That is why I suggested a test with flexible wire first, as that would be non-destructive.

Cable control is also a good option as long as it meets your performance needs and you have the extra hand free to push/pull the cable.  

/Chris