Pneumatic engine reversal switch

[Electricsteam]

I have been building another pneumatic locomotive for my railway but I want it to go forwards and backwards and I am going to have the Vavle Gear in the tender. So could you please check my blueprints and see if I have it down to where it will work?

The evolution of the ES co. Behemoth locomoive.

Edited March 12, 2013 by Electricsteam

[Bzroom]

I think the problem is that:

since the two switches on the left are connected in parallel, but reversed, as air flows through one, it will flow out the other's vent, and not into the cylinder.

With electronics you could solve this with back-flow diodes. But i think the problem may be even easier to solve.

What do you think of this configuration?

It uses a "DPDT" switch as the pole reverser, and the cycle valve stays the same as with no reverser.

Actually, i think my reversion would have the same "blowing air out the vent" problem. :/

Edited March 12, 2013 by Bzroom

[Boxerlego]

A one way air valve for a fish tank would solve the problem with the air escaping from the other valve but you would need 4 one way valves for it to work

.

Edited March 12, 2013 by Boxerlego

[Electricsteam]

A one way air valve for a fish tank would solve the problem with the air escaping from the other valve but you would need 4 one way valves for it to work

.

I was going to have the robot claw on the other end of the tubes to stop the air from escaping. I forgot to mention that reverser is only for one side of the Locomotive there is the same setup on the oposite side of the locomotives tender. Edited March 12, 2013 by Electricsteam

[Nazgarot]

Hi,

I can't see exactly how you intend this to work, but maybe this part could help you. I've used it several times to make suction pumps, and avoid water getting into the pump. It works as a one way vent where you have input on one side linked to input/output in the middle, and output on the other side. (In short, air only flows from left to right)

-ED-

[Electricsteam]

As the vavle gear turns it runs the air current to the piston. The reversal switch is suppose to flip the sides of where the piston intakes air ,thus reversing the direction the Locomotive moves. One of my problems is I need to keep the drive shaft in the tender to keep turning the same direction for this to work I believe.

[Saberwing40k]

How about you just include a little reverse gearbox, such as this one:

It's by ErikLeppen, and I think it would be easier to implement than actually reversing the engine, which I think is actually not possible, or at least I have never seen it done.

[Boxerlego]

I was going to have the robot claw on the other end of the tubes to stop the air from escaping. I forgot to mention that reverser is only for one side of the Locomotive there is the same setup on the oposite side of the locomotives tender.

I dont know if this will work with your pneumatic reversal switch idea but you could control the pneumatic piston off four valves with each valve combining the exhaust and intake. You would have two sets of valves, one for forward drive and the other set for backward drive.

[Electricsteam]

How about you just include a little reverse gearbox, such as this one:

It's by ErikLeppen, and I think it would be easier to implement than actually reversing the engine, which I think is actually not possible, or at least I have never seen it done.

It has to be possible! And the Idea you had will not work because the pistons are moving the train wheels directly!

[Bzroom]

Your comment about the drive shafts gave me an idea.

You can have two complete sets of drive shaft vales, configured to run the piston in each direction.

Then you can select between the two systems to choose a direction.

edit: I just noticed BoxerLego beat me to it!

Edited March 12, 2013 by Bzroom

[Electricsteam]

Your comment about the drive shafts gave me an idea.

You can have two complete sets of drive shaft vales, configured to run the piston in each direction.

Then you can select between the two systems to choose a direction.

edit: I just noticed BoxerLego beat me to it!

I didnt understand what he was getting at becuase he didn't have charts like you!

[Bzroom]

I think the red split will still pose a problem, because when one drive shaft valve becomes inactive, it will become the path of least resistance. The air will just flow out that valve.

You may need to tie in a 3rd reverser valve on the red fork, to deactivate the valve entirely.

This is becoming quite heavy duty. I hope there is a more elegant way.

Edited March 12, 2013 by Bzroom

[Electricsteam]

I think the red split will still pose a problem, because when one drive shaft valve becomes inactive, it will become the path of least resistance. The air will just flow out that valve.

You may need to tie in a 3rd reverser valve on the red fork, to deactivate the valve entirely.

This is becoming quite heavy duty. I hope there is a more elegant way.

... I only have about a 6-wide space thats why every thing needs to be compact the valve switch will have an 8-wide space.

[Bzroom]

Can you fit 5 switches in there?

3 of their levers linked together, 2 of their levers attached to the drive shaft cam?

what is the total volume you have to work with? can you make a sketch?

[Electricsteam]

Its about a 8x20 space without walls and 6x20 with walls.

[Lipko]

Where does the valve vent?

Is it possible to block that hole with some rubber part?

Maybe that would help.

[Bzroom]

Its about a 8x20 space without walls and 6x20 with walls.

How many bricks tall?

[Electricsteam]

How many bricks tall?

Give me some time I need to build a moc-up tender for that...

[Carsten Svendsen]

I don't know if

Your comment about the drive shafts gave me an idea.

You can have two complete sets of drive shaft vales, configured to run the piston in each direction.

Then you can select between the two systems to choose a direction.

edit: I just noticed BoxerLego beat me to it!

This'll work, you just need a valve placed at the red Y-split that's moving with the drive shaft valves.

Edited March 13, 2013 by Carsten Svendsen

[Boxerlego]

Instead of making a pneumatic reversal switch to switch the engine direction. Go for the mechanical solution to reverse the engine. This way you can still have one pneumatic valve on the engine design. This Stephenson valve gear would solve this challenge very effectively. What do you think?

[Electricsteam]

Instead of making a pneumatic reversal switch to switch the engine direction. Go for the mechanical solution to reverse the engine. This way you can still have one pneumatic valve on the engine design. This Stephenson valve gear would solve this challenge very effectively. What do you think?

... There is no room on the locomotive for it to still look nice that is why I wanted he valve and reverse switches in the tender...

[Bzroom]

Instead of making a pneumatic reversal switch to switch the engine direction. Go for the mechanical solution to reverse the engine. This way you can still have one pneumatic valve on the engine design. This Stephenson valve gear would solve this challenge very effectively. What do you think?

That is an amazing linkage!

Edit:

I was looking for a mechanical solution that would allow me to continuously transition from forward to reverse. Since the travel is not continuous, this seems to be the ticket!

This thing would look very nice on the side of the locomotive, you could use half thick lift arms, attaching the valve just above the cylinder. It appears that this would be the most elegant and effective method, working just like the real thing.

To summarize how the linkage works, the important part is the rocker arm. Each side of the rocker is traveling the opposite direction. If you could variably adjust where the valve attaches to the rocker, you could control both the direction and range of travel of the valve. This gives you continuous adjustment from reverse-full-power to no-power, to forward-full-power, with one adjustment.

You can see that the rod attached to the valve can travel up and down the rocker, based on the angle of the cam.

http://upload.wikimedia.org/wikipedia/commons/1/10/60163_Tornado_motion.jpg

Edited March 13, 2013 by Bzroom

[Electricsteam]

Ok here is the locomotive so far!

http://www.eurobricks.com/forum/index.php?showtopic=80505

[Bzroom]

That is awesome dude! I really hope you can rig up the valve on the outside with the crazy reverse linkage thing.

I really want to buy some of these wheels and give this a shot! Is there a recent set that sells these steam powered wheels? Or are these old school/need to be ordered off brick link?

[Electricsteam]

That is awesome dude! I really hope you can rig up the valve on the outside with the crazy reverse linkage thing.

I really want to buy some of these wheels and give this a shot! Is there a recent set that sells these steam powered wheels? Or are these old school/need to be ordered off brick link?

They are BBB XL drivers. And no I am not going with the linkage mostly becuase I NEED that sliding block and the only valve gear linkage made was for no pneumatic use and has no strength to support the pistons.