Crank opperated hydraulic?

Interesting task (having read your answers to others). Me just knowing the basics of hydraulic, I would do:

• calculate the volume you are pumping back and forth.
• check mfgs wether their tubes can handle that volume in time (l / sec; or gallons per second). Dimension the tube to handle it easily.
• check for heat generated (flow resistance in tubes / cyls.). Does it require a cooler?
• Do you need valves that are electrically controlled?
• consider having an air trap / refill valve.
• select pistons that can handle that speed over a long time (contact mfgs)

HTH, Nick

Don Foreman wrote in news: snipped-for-privacy@4ax.com:

Yup, but they are only pulsed for short periods of time. Not a 24/5 operation, nor even an 8/5 operation. The other thing is...anti-lock brakes are mostly relieving pressure that has already been applied.

You and your voice of reason...buzzkill!

Air already does a bunch like clamps, wire advance, lock-outs and such. Actually, I think now after airing it out that we have the mechanical sollution perfected to the point of maturity. I'll know better after this second machine gets some experience and shows it's weeknesses. Number one went through some retrofits at the 6 month mark and has a

Lookin' like I'll stay with the mechanical!

Hi Tom

I've seen some hydraulic hammers and chisles that dont leak noticably after a year of hard use. I think Don's idea is worth trying, unless there is a better method available. I'd expect a routine maintenance schedule could provide a high degree of functioning time on Don's type system.

Jerry

I'm sure it could be done. Look at diesel injector pumps, they work at over 10000 Psi and run for years at over 1200 RPM without leaking.

Not necessarily. I said I don't know -- they may be good for millions of operations between rebuilds. They might well outlast mechanical bushings,bearings and cams for all I know. It's certainly worth checking. Someone mentioned diesel injectors as one example.

You have an elegant solution that works Just Fine.

--Winston

The pistons have nearly no travel, but only transmit force.

Nick

He's talking about delivered power on the order of 130 watts or so. (Do the math.) Even if the system is only 50% efficient, which would be rather poor for hydraulics, that's less than 70 watts of heat to deal with. That should be a yawner.

Solenoids are terrible prime movers except in bang-bang apps, and even then they are very inefficient at producing significant motion. Tawk about heat! (Do the math)

Usual hydraulic experience is at much higher power levels -- tons of force, feet of motion, many horsepower. That's a whole different ballpark. Even a little inefficiency produces a lot of heat at those power levels. Experience is helpful only if it's relevant and applicable.

The cycle rate has nothing to do with wear rate or production of heat by friction. Those are functions of velocity, whether or not it's cyclic. 3/8" in 0.1 second is a velocity of 3.75 inches/sec, not exactly blinding speed.

Roller chains, sprockets, cams, bushings and bearings also wear. It is not at all obvious that a hydraulic system would wear any faster or even as fast as these components. That would have to be investigated to reach an informed opinion or conclusion.

Even if the desired motion is produced by cams, levers, chains and sprockets with bushings and bearings yada yada, long-lived reliable hydraulics might have a lot of value if it made those mechanical wear items more accessable and thus more easily maintained. That would certainly depend a lot on the application.

All that said, I sure don't argue with "if it ain't broke, don't fix it." One could surely learn a lot about hydraulics by trying it here, and that knowledge would very likely spawn viable new ideas for other applications even if it didn't work out here for some reason. But, at the end of the day, the name of the production game is goods out the door, not farting around with experiments.

Let the Asians waste their cheap time dinking around with new ideas, nyahhh!