"hydraulic " power hammers.

[basher]

are there any ?
I am thinking of at some point running my brooks hammer with a hydraulic motor as that seems to give a very good potential for variable control over the hammers action , this is really only because I have one and want to try it rather than making up some kind of slip clutch....
this got me thinking.
what are the potentials for a hydraulic power hammer ? ie one actually powered with a hydraulic piston ?
either a small gauge piston or slightly larger one working a whipy spring helve?
fast enough to act as a hammer rather than a press?
would the quick changes in direction over heat pipes and cylinders ?
I imagine that hydraulic solenoid valves are pretty xxxxxx quick.
I would imagine the main problem being cost of parts .

[arftist]

You can use a hydraulic motor if you like. Poleframer did, and reports that it works well.

As for piston driven, they also exist. The problem is partialy cost as noted. Think BIG pump, and horsepower.

[Ric Furrer]

How about these at Scot Forge?
http://www.scotforge.com/videos/sf_press320_240.mpg
http://www.scotforge.com/videos.htm

I have seen 24 ton presses that we use in shops with a cycle rate that was very fast...and micro switches which allowed the press to cycle between given distances...much faster than a human could do.
I guess the idea is what are you doing and what tool best gets you there.
I would think a 2" cylinder could work like a 25 little giant off a 2 HP motor and micro switches to a solenoid.....maybe hard on the cylinder over time, but they are cheap. If you set it up to work off a short stroke 1/8" to 1/2" and then set the upper and lower limit would make short work of even small bars.

Actually if you did not need to eat large pieces you could set it all up inside an "I" beam and make it rather portable....the issue as you said is heat...you would need to cool the oil or have a large container.

Ric

[poleframer]

I'm working on my 2nd hydraulic powered hammer now. Doing a "rusty" style, but use a hydraulic motor to a drag link to the leaf springs. I get great control using a flow control valve with linkage to the foot pedal. I'll put up a vid when done. It also has a 60 ton forging press, and a 25 ton punching press in the frame. This one uses springs from a dump truck, 5 foot long, 3/4" thick each at the center, 65 lb hammer.
You can check out some vids of my first one in my JYH and press thread.
I think a 2 stage pump would work, I never see over 500 psi when I'm running the hammer at about 10 to 12 gpm.
Be happy to answer any questions you might have.
Russell

[Nakedanvil - Grant Sarver]

Well, I've given a lot of thought to hydraulic hammers and I'll just list a few things that I've observed, calculated and thought about.

If you've ever seen a Rockford Hydraulic shaper running flat out, you know that a hammer could easily be made.

To move fast you need large ports and plumbing, which means a large cylinder, which means you only need a hundred pounds of pressure or so.

A high-pressure centrifugal pump wold work.

With no elasticity (like air) very little stroke is required for acceleration. So the stroke could be made, say, two-inches or so and use the treadle to control where it runs that two-inches over a 12 to even 20 inch range.

Be interesting, not sure it would have many advantages over air.

[nonjic]

There are lots of hydraluic hammers out there in industry, they tend to be over 1 ton ram weight.

Oil lifts the piston under the cylinder head, this compresses nitrogen above the piston head. The compressed nitrogen provides the energy to the blow when the oil is released from under the piston head.