Periaktoi Detent?

bobgaggle

Well-Known Member
Doing some preplanning for a tv set with 5 small (16" side) periaktoi nestled in a little cove in the wall. I wonder what you guys have done when it comes to locking them in place. They would be preset before shooting, so no live movement. I want to make sure they can be fixed in place, I'm leaning toward a linkage for all 5 for ease of transitions and it seems like it would make locking them easier. Any ideas? Ball catch, pin through the link arm into something, maybe just more friction in the pivot?
 
Doing some preplanning for a tv set with 5 small (16" side) periaktoi nestled in a little cove in the wall. I wonder what you guys have done when it comes to locking them in place. They would be preset before shooting, so no live movement. I want to make sure they can be fixed in place, I'm leaning toward a linkage for all 5 for ease of transitions and it seems like it would make locking them easier. Any ideas? Ball catch, pin through the link arm into something, maybe just more friction in the pivot?
Economy / Cheap / Disposable paint brushes dragging hard on the floor underneath; similar to holding a hinged door ajar.
Toodleoo!
Ron Hebbard
 
Periaktoi Detent - that would be a good band name.

Wooden gears might work well to connect them together. You could use Matthias Wandel's gear generator: https://woodgears.ca/gear_cutting/template.html

I wonder how the advertising signs handled this issue?
Here are a couple of clips showing the mechanism in a trivision display:
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Here is a fun theoretical design:
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the geneva wheel makes sense for holding position. I can't figure out how they did it in the first video
 
I can't figure out how they did it in the first video
It looks like there is a hexagonal profile below the bevel gear at the bottom of each piece of the display. The actuation shaft has a narrow channel that prevents the hexagon from turning for the majority of the shaft's rotation, but when the partial gear meshes with the piece to turn it, the channel widens to allow for rotation.
 
With no live movement, why bother with any linkage?
In the past I've used ball catches on a Delrin disc but three strong magnets on the bottom (or top) of each periaktos and another on the static structure should do the job without needing any other fabrication.
Doing some preplanning for a tv set with 5 small (16" side) periaktoi nestled in a little cove in the wall. I wonder what you guys have done when it comes to locking them in place. They would be preset before shooting, so no live movement. I want to make sure they can be fixed in place, I'm leaning toward a linkage for all 5 for ease of transitions and it seems like it would make locking them easier. Any ideas? Ball catch, pin through the link arm into something, maybe just more friction in the pivot?
 

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