Engaging Gears Perpendicular to Shaft Direction?

[Matt Adams]

Originally Posted by Joe Johnson

Have to done a careful sum of the moments calculation about the axis of rotation of the input shaft?

I am suspicious that the drive link can stay engaged with just the aircylinder.

eeek... I gotta say I didn't do that! (Though admittedly, small things like how much those shafts would deflect when they had a pneumatic on them were definitely calculated (.00045 inches))

To do so real quick:

Maybe 250 in-lbs on that center gear, 1 in diameter, moment arm of a half inch off center... the pneumatic is about 3.4 inches away from the pivot point, at around a 15 degree angle, providing a max moment arm in the opposite direction of around 95 lbs * 3.4 inches with a 1.5 inch bore... There's also the force on the gears through the shaft centers, sin(20)*250 is around 85, times it's moment arm of 1.5.... So we've got around 70 in lbs to spare with the half inch. whew! Thanks for the reminder...

Originally Posted by Joe Johnson

#1 I alot of careful thought has gone into this. Careful thought is never wasted.

I appreciate you noticing, and while this is true... sometimes outsiders see something obvious that the "careful thought" folks have missed which will make a device infinitely better... which is why it's out here.

Originally Posted by Joe Johnson

#2 My brain keeps coming back to, why have the engage/disengage gears at all? You have the chain sprockets. Why not just mount the gears and their shafts on the pivoting link, keep the gears engaged 100% of the time and just pivot the whole mechanism to allow the "high gear" sprocket or the "low gear" sprocket to engage the chain? I think your mechanism gets simpler, your gear loads and forces are more easily managed, and the chain takes all the abuse.

I've reread this about 10 times now.. I just can't visualize what you're saying. Are you suggesting having some loose chaing that is engaged and disengaged with sprockets? If you keep the gears engaged constantly.. how would you shift?

I've already thought of some nice ideas about changing the sizes of the blue connecting sprockets to let them affect the gear ratio, and keep the gears a (larger to reduce load) constant size... but I'm certain this is not what you're proposing. If you could clarify, I'd truly appreciate it!

Thanks,

Matt