Fast acting single action cylinder

[nwngunner]

I have been looking at building a post pounder for my track loader. What I am thinking about doing is a falling anvil design. How ever I dont want to use ropes and pullys.

Now, what I am thinking of doing, the out port on my skidloader would go to a 12volt valve. So what I want is the port on the single action cylinder oversized. To say one inch. Allow as much flow in and out as fast as possible. Use as small of a cylinder to lift the anvil as I can. The cylinder goes up, trips a switch, the 12 volt valve switches posistions, the return of the valve goes straight to the tank. The weight pushes the fluids out, anvil drops. Hits another switch, the valve switches again, the cylinder closes.

What valve do I need, and can the single action cylinder work how I want it to? At the top stroke, I would use a rubber bushing to keep the cylinder from slamming on its self or put the dump switch before end of stroke. I think this would work great, as long as I can get the cycle speed I want. The return speed isn't a big deal its the drop speed I need, figuring about 700 pound anvil.

 

[4570Man]

I would be really surprised if you can get the drop speed. How does a commercial built post pounder work?

 

[J_J]

They use springs to help eject the fluid.

http://www.shavermfg.com/media/uploads/HD-10-operator-manual.pdf

 

[BHD]

on my post pounder I use a single action cylinder and enlarged the input port, I have a 400 pound weight and it drops plenty fast, I used 1/2" valves and hose, (I may have used 3/4 on the cylinder and return line),

 

[bcp]

Interesting question. I spend about 20 minutes looking at post pounder videos.

Most post drivers have a cylinder with a bunch of pulleys and cables for speed and distance.

Other Methods
=========================
Big hammer:

https://www.youtube.com/watch?v=IFD2w06staY

https://www.youtube.com/watch?v=UIjZ_ggc0gk
===============
Cable and lever:

https://www.youtube.com/watch?v=TqEQaBiMIUQ

https://www.youtube.com/watch?v=FR-Njtmf4OU

https://www.youtube.com/watch?v=Tgy1gqwWsfM

===================

The other common mechanism was a vibratory pusher.

====================

I found none that used a direct-to-the-weight hydraulic cylinder.

Bruce

 

[nwngunner]

Could get a tall coil spring from a 1ton truck should provide enough force if I doesn't drop fast enough

 

[oldnslo]

I have been looking at building a post pounder for my track loader. What I am thinking about doing is a falling anvil design. How ever I dont want to use ropes and pullys.

Now, what I am thinking of doing, the out port on my skidloader would go to a 12volt valve. So what I want is the port on the single action cylinder oversized. To say one inch. Allow as much flow in and out as fast as possible. Use as small of a cylinder to lift the anvil as I can. The cylinder goes up, trips a switch, the 12 volt valve switches posistions, the return of the valve goes straight to the tank. The weight pushes the fluids out, anvil drops. Hits another switch, the valve switches again, the cylinder closes.

What valve do I need, and can the single action cylinder work how I want it to? At the top stroke, I would use a rubber bushing to keep the cylinder from slamming on its self or put the dump switch before end of stroke. I think this would work great, as long as I can get the cycle speed I want. The return speed isn't a big deal its the drop speed I need, figuring about 700 pound anvil.

I presume that your skid loader is open center auxiliary system.

Depending on the flow rate from your skid loader this could be as simple as a 2-way poppet style valve that dumps both the pump & cylinder exhaust to tank through the same line. Delta Power, Hydra-Force are two companies that make this style of valves. The size -16 can handle 40 GPM with minimal pressure drop.

Can you confirm that theretun flow will be entering the tank below oil level? If not you may have an oil aeration issue after a short run time.

Other option is larger 3-way valve but these are harder to find that will handle higher flow rates.

 

[J_J]

I believe the Shaver units use a Gresen valve.

Tank hose is either 3/4 or 1 in.

Your pump will dictate the speed of operation.

 

[nwngunner]

The pump on my skid loader is 25+ gpm non highflow. I have a snow plow i built that out of a truck plow i had to put restrictions in to keep from blowing the cylinders up. I taped the button and it would slam the cylinders. I dont know about the aeration issue how ever.