Critique Solicited

[Mr.Entropy]

I have 3 concepts that I would like to present for your consideration. I'm specifically looking for constructive criticism.
This is the first concept. Hopefully, self-explanatory but I can describe the action in a follow-up response.

I see what you're trying to do, but if your pivots are free to pivot, then moving the balls to the other side of the trays does NOT alter the balance and tip the contraption in the other direction.

On the other hand, if you glue the pivots so that they can't pivot, then moving the balls DOES alter the balance and tip the machine, but then the trays will tip, and moving the balls back will require energy.

[noonespecial]

I have 3 concepts that I would like to present for your consideration. I'm specifically looking for constructive criticism.
This is the first concept. Hopefully, self-explanatory but I can describe the action in a follow-up response.

I see what you're trying to do, but if your pivots are free to pivot, then moving the balls to the other side of the trays does NOT alter the balance and tip the contraption in the other direction.

On the other hand, if you glue the pivots so that they can't pivot, then moving the balls DOES alter the balance and tip the machine, but then the trays will tip, and moving the balls back will require energy.

That's correct. I think you responded just before my last post.
Think of the tray and counterweight arm as one assembly. The counterweight is sized so that when weight "A" is at its furthest point either left or right, the tray (and arm) maintains a 5 degree angle throughout the arc of motion.

[fletcher]

IMO, both A & B  'T' bar pendulums will move to their respective balance points i.e. where their individual CoM/CoG is beneath their pivot - because they are linked via a parallelogram arrangement they will find a position of equilibrium between them - there will be some movement of the main teeter-totter from inertia re: action & reaction, & the T bars will continually adjust their balancing points below their pivots - the CoG of the whole arrangement will seek & find its lowest Potential Energy [it only initially moves because you have arranged it in a favourable position, to start with more PE than it would otherwise have] - when the momentum of seeking the lowest PE is used up by friction & windage etc the apparatus will stop its dampened swing & stand stationary with its CoG directly beneath the center pivot.

As far as I can tell the arrangement will act as an dampener of movement [leading to stability] rather than creating a constantly unstable device [leading to instability - an un-natural state].

[rlortie]

I  agree with Fletcher's  opinion (as usual :--) , although I would have stated it some what different.

The two pendulums are symmetrical pinned to the cross arm. I recommend you study the principles and effects of the:
http://en.wikipedia.org/wiki/Roberval_Balance  http://www.lhup.edu/~dsimanek/museum/roberval.htm

Ralph

[noonespecial]

I  agree with Fletcher's  opinion (as usual :--) , although I would have stated it some what different.

The two pendulums are symmetrical pinned to the cross arm. I recommend you study the principles and effects of the:
http://en.wikipedia.org/wiki/Roberval_Balance  http://www.lhup.edu/~dsimanek/museum/roberval.htm

Ralph

Hi Ralph,
Thanks for the reference. However, unless I'm missing your point my mechanism CAN tilt whereas the balances in the reference article cannot. The traditional balances shown are pinned in the center of both arms but mine only on the main beam. So I don't see the similarity.