# Help making a head pivot



## Mav9709 (Oct 18, 2013)

I am building a headless horseman prop but I am having trouble automating the neck pivot mech. I would like to use pneumatics and not a stepper motor. Any ideas?


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## bfjou812 (Aug 15, 2008)

How much space do you have to work with? How much do you want the head to pivot? You could do it with another cylinder by mounting the head on a pipe that runs from top to bottom and use some one hole conduit clamps or use a linear actuator and a gear rack.


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## Mav9709 (Oct 18, 2013)

Bfjou812 thanks for responding, the sketch in the lower left shows the movement I'm looking for. I used some wisdom from another post I read some time back about using cardboard and brass clips so I started experimenting and came up with a possible scenario using a double ended cylinder. I will have about 12" to work with. Attached is the pic, do you think this might work?


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## bfjou812 (Aug 15, 2008)

I don't think that will work, I think it will jam. Does it work with your mock up? It seems like it is going to be in a constant bind. If you have a way to get feedback from the cylinder then you could use a single cylinder where fully extended is left ,fully retracted is right and half extended is straight by using something like you have set up there .you could mount the cylinder several ways.


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## fontgeek (Jul 24, 2006)

You might consider cheating a bit.
With the head and neck on a fixed hinge, you could use a cylinder to push the head/neck to one side, a spring to pull it back as the pressure is released on the cylinder. I don't know how noisy your scene will be but even one cylinder "Gasping"/releasing it's air, may be more than you want to deal with.
How much do you see the head and neck weighing? That load is something you need to consider, regardless of how you plan on moving it.
Just thoughts from the cheap seats.


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## Mav9709 (Oct 18, 2013)

Bfjou812-I like the thought of using the cylinder with different positions but after researching I believe I will need a magnetic position sensor or a reed switch and I am not sure how to control those.
Fontgeek-Thanks for chiming in, any comments are appreciated. I am not sure of weight yet, I plan on using 3/4" square stock for head, neck, front legs, and maybe spine. I plan on using PVC and chicken wire for the form. Not sure on how to "flesh" it out yet. I will need access to the inside. I'm sure it will be heavy.


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## heresjohnny (Feb 15, 2006)

I don't know much about pneumatics, but I do okay with mechanical stuff. I use cardboard and tacks to figure out linkages myself, and described the technique in my cloaked ghost build.

It looks like you have the neck hinged at 2 points, which will take a lot of stress off of the hinges, and which means the weight of the head will have less impact as long as the neck swings back and forth in a horizontal plane. To move the head back and forth I would extend a control arm back into the body of the horse, swinging this side to side will move the head back and forth, and looking at your drawing you should have room. I would make the extension longer than you think you will need, then try connecting whatever actuator you use at different points to get the range of movement you are looking for.

Hope this helps!


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## master of disaster (Aug 2, 2014)

*3 point*

A typical 3 point system works best for necks to mimic all movements. The back is just a ball joint stand and the front two are operational for left and right lean and up and down when both move together. A superior system that works for many other joints too. The down fall is you will need ball joint for all locations. I have made many out of wood corion and steel. Do leave me a message if you need more info, I check back every now and again. Steve.


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