Servo linkage headache

Gramps

Senior Member
Watch "March 19, 2020" on YouTube

The problem is connecting the servo to square stock.
This is one way to do it.

Watch "March 19, 2020" on YouTube

We need 120 degrees variation but can only get 90 with this configuration.
We could use a shaft directly connected to the servo hub and a belt drive, however would rather have a linkage connection if possible.
Been scratching my head all afternoon. Perhaps someone has that brilliant simple solution!
Thanks, Gramps
 

papaof2

Senior Member
Why not mount the box directly to the servo? If the servo can't support the weight, use gears to turn the box on whatever mount it needs.

If you need large, inexpensive gears, look for a discarded bicycle. Perhaps use chain drive with bicycle sprockets? The chain drive could also provide up or down gearing of the servo's rotation distance.
 

techElder

Well-known member
We need 120 degrees variation but can only get 90 with this configuration.
Don't know if this helps (or just states something obvious to you), but your servo bracket is traveling on a different radius than your square bracket. You'll never get the two to rotate to the same degree without some gearing or leverage.
 

erco

Senior Member
Much improved, Gramps!

Linkages are awesome, I credit my '67 Corvair with making me an engineer. Four synchronized carburetors were connected via linkages with progressive rates to the two secondary carbs. Good times!
vair140.jpg
 

tmfkam

Senior Member
Lovin' that belt drive! It's a work of art. And the intricacies on the fuel lines. Motive sculpture is the only way to describe that. Beautiful.
 

techElder

Well-known member
@Gramps Now all you need is to get you a "popsicle stick" with a curve in it. :D Just keep the end points in the same place, and you can curve it to the back door and back without changing the motion characteristics. +1
 

Gramps

Senior Member
Oh yes now I have an excuse to buy that CNC machine:cool: perfect for creating curved popsicle sticks!
 

oracacle

Senior Member
ha, just built a CNC, trying to get everything setup correctly now.
Its going to complement the 3D printers nicely once its finished.
 
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