What happens when you have equal force on opposing sides of a 2:1 gear train?

[TaylorTexas]

I have studied how gear trains work for a project I am working on, but can't find an analogous situation where the forces in the gear train oppose each other. Can someone help me?

I have a 2:1 gear ratio on a dual rack and pinion gear train connected to opposing pistons, and there is equal force on both pistons (force = 2). In order to help me understand what will happen, can you tell me in what direction will each piston move and how far?

Force -->|piston1|----------(1:2 gear train)----------|piston2|<-- Force

 

[russ_watters]

If the forces are equal at first, the system will accelerate. What happens then requires more information. How are the forces applied? How big are the gears? How big are the crankshafts?

 

[TaylorTexas]

The device is in an environment with ambient pressure, so the forces are equal on both pistons. The top of the pistons are exposed to the environment and there is a single sealed chamber connecting the pistons and containing the gear train. The opposing pistons are connected to shafts (pinions) attached to a 2:1 gear train. Both gears are on the same axis (like a minute hand and an hour hand but in opposite directions). One piston pinion is connected to the 1 gear, and the other piston pinion is connected to the 2 gear. No crankshaft.

Normally, when the ambient pressure increase, the volume of the piston chamber would decrease. I would like to use a gear system so that when the ambient pressure increases, the volume of the piston chamber increases as well.

However, I think piston 2 will be pushed all the way to the gear train keeping the same volume in the piston chamber. Am I right? Is there any way to accomplish my goal of increasing the volume?

 

[TaylorTexas]

Here is a link to an image of a sketch of some possible designs:

Link to SkyDrive image