Machining a gear
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I’m trying to visualize such a gear as drawn and I cannot. M.C. Escher might manage it. There are ‘ball gears,’ but the teeth are discreet diamond shapes.
dnalot
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That would be called a crowned ball gear. I have seen those in use on very old aircraft control yokes.
Mark T
Mark T
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The pitch Ø should be the same for the forward as for the aft, if you want the legs to move in sync. I believe this was meant for a kid to ride on.
I would set my indexer on the rotary table to get the correct arc on each gear peak/valley. Kinda hard to explain.
Modulus of 1 (metric) with 20 degree pressure angle would work for your scale. That way you could test with lego gears too before committing.
I think a swash plate would work better but the complexity would make it a fun project!
@dnalot What aircraft were those on? That's pretty interesting.
I would set my indexer on the rotary table to get the correct arc on each gear peak/valley. Kinda hard to explain.
Modulus of 1 (metric) with 20 degree pressure angle would work for your scale. That way you could test with lego gears too before committing.
I think a swash plate would work better but the complexity would make it a fun project!
@dnalot What aircraft were those on? That's pretty interesting.
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dnalot
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I think part of the issue is the patent drawing has an error. The teeth are shown in a mirror image symmetrical to the pivot point. They would all curve in the same direction. Still sort of a hassle to make, but as there is little power being transferred a less than perfect fit will still work as long as it isn't so loose that the gadget works poorly. For a small model I'd be inclined to 3D print at least the "weird" gear and see it the gear outlasts the novelty of seeing it work 
3D printing all of the gears might not be a bad idea, just add enough meat to carry the pins / shafts that couple to the actuating arms/lever. Keeping the legs as light as possible would be important as there is quite a bit of leverage there.
Looks like a fun little gadget, could be a nice project for those who like automata / mechanical toys.
Cheers,
Stan
3D printing all of the gears might not be a bad idea, just add enough meat to carry the pins / shafts that couple to the actuating arms/lever. Keeping the legs as light as possible would be important as there is quite a bit of leverage there.Looks like a fun little gadget, could be a nice project for those who like automata / mechanical toys.
Cheers,
Stan
