Making a press/ram with multiple bottle jacks/rams? Can anyone see problems with this

I was wondering if it is possible to use a number of hydraulic jacks to make a higher capacity press? I'm looking at 2 or 3 different types of jacks:
Pneumatic actuated
electrically pumped
hand "cranked"

The press needs to exert force over a fairly small area - maybe 4-6" wide. I've looked at the jacks and it looks fairly easy to fit 2 or 3. I would have to make some kind of very robust plate to connect more than one jack but I suspect it can be done.

I was looking at some hydraulic rams used on log splitters and I think these would work pretty well when joined together. I would have all the jacks connected in parallel so each gets the same amount of pressure and oil for each stroke of the pump. BTW, I would use identical rams for this. I think the same could be done with pneumatic jacks.

The reason I'm looking at multiple pumps is b/c there are only certain times when I would need multiple rams/jacks and the majority of the time, each ram will be on or used in a different application/station and I could combine them every once in a while when I need them.

So is this a plausible option and can anyone see any issues with this (again assuming the plate(s) that joins the ram lifing surfaces to each other is robust enough)?

One of the main reasons I'm looking at using multiple hydraulic rams from wood splitters is the length of the stroke, which will make things much easier.

tuprox said:

I was wondering if it is possible to use a number of hydraulic jacks to make a higher capacity press? I'm looking at 2 or 3 different types of jacks:
Pneumatic actuated
electrically pumped
hand "cranked"

The press needs to exert force over a fairly small area - maybe 4-6" wide. I've looked at the jacks and it looks fairly easy to fit 2 or 3. I would have to make some kind of very robust plate to connect more than one jack but I suspect it can be done.

I was looking at some hydraulic rams used on log splitters and I think these would work pretty well when joined together. I would have all the jacks connected in parallel so each gets the same amount of pressure and oil for each stroke of the pump. BTW, I would use identical rams for this. I think the same could be done with pneumatic jacks.

The reason I'm looking at multiple pumps is b/c there are only certain times when I would need multiple rams/jacks and the majority of the time, each ram will be on or used in a different application/station and I could combine them every once in a while when I need them.

So is this a plausible option and can anyone see any issues with this (again assuming the plate(s) that joins the ram lifing surfaces to each other is robust enough)?

One of the main reasons I'm looking at using multiple hydraulic rams from wood splitters is the length of the stroke, which will make things much easier.

Click to expand...

2-Post Presses | 2 Column Presses | Cost Efficient Presses

Thanks - that is basically what i was describing, so it looks like it should work.

The ram experiencing the least amount of resistance will always extend faster causing a mismatch in the stroke between the two. Multi ram presses take care of this through the use of a flow divider or an active means like individual servo control.

With a small, rigid mounting of the ram you might be able to pull it off but be prepared for the worst.

K

If you can find double-acting double-rod end cylinders (think steering rack cylinders), you can hook them up in series, which will ensure the same volume of oil is sent to both cylinders*, regardless of load imbalance. Filling and bleeding a series system is more complicated than dumping fluid in the reservoir for a single-acting parallel system. And you need to find a useless volume for the "unused" rod ends to travel through while operating the press. But it's considerably less involved than servo control.

* (Assumes both rods are the same diameter, which is usual for double-rod end cylinders.)

Keep the construction simple. While you might figure out how to plumb a couple of jacks together, the pressure platen needs to have a balanced load. Operating only one of two jacks is not going to be easy to when it comes to the pressure platen coming straight down on its guide rails.

If you need high tonnage, then just build a single larger cylinder. Every inch you add to the diameter of the piston adds a lot of square inches for force multiplication. But paralleling cylinders doesn't add up as fast in pressure benefit, compared to the amount of additional hardware required.

Building something that is cumbersome to operate is just a waste of time if it is too much of a PITA to operate it. I hate shifting even a gear shift, when it is handy

You just need a central guide running in bushes ,and you can have any number of rams disposed around it.I would only do it for reasons of space.......one cylinder of larger diameter is preferable.......with air ,you dont get much push ,and more importantly ,the ram is a loaded weapon as long as there is air pressure in it......In other words ,if the load is suddenly released ,the ram will extend at high speed.

tuprox said:

I was wondering if it is possible to use a number of hydraulic jacks to make a higher capacity press? I'm looking at 2 or 3 different types of jacks:
Pneumatic actuated
electrically pumped
hand "cranked"

The press needs to exert force over a fairly small area - maybe 4-6" wide. I've looked at the jacks and it looks fairly easy to fit 2 or 3. I would have to make some kind of very robust plate to connect more than one jack but I suspect it can be done.

I was looking at some hydraulic rams used on log splitters and I think these would work pretty well when joined together. I would have all the jacks connected in parallel so each gets the same amount of pressure and oil for each stroke of the pump. BTW, I would use identical rams for this. I think the same could be done with pneumatic jacks.

The reason I'm looking at multiple pumps is b/c there are only certain times when I would need multiple rams/jacks and the majority of the time, each ram will be on or used in a different application/station and I could combine them every once in a while when I need them.

So is this a plausible option and can anyone see any issues with this (again assuming the plate(s) that joins the ram lifing surfaces to each other is robust enough)?

One of the main reasons I'm looking at using multiple hydraulic rams from wood splitters is the length of the stroke, which will make things much easier.

Click to expand...

so each gets the same amount of pressure and oil for each stroke of the pump.

There is your problem Not automaticly so If you put them in parralell pressure will be the same but not the stroke Pressure depends on the load and if the load is not devided evenly you get different strokes till the loads even out You better keep the volume to each jack the same With 3 jacks and one pump not that easy
Each jack his own pump would be easier but still a pita
Peter

IF you have a load that is exactly centered between the rams the dual ram with parallel hydraulic connection setup could be ok. But if that load is shifted even a little bit, the ram farthest from the load will extend further, distorting your setup, possibly bending your frame or shooting out a dieset or part. Others have suggested that coordinated positive displacement pumps (essentially two or more gear pumps with the shafts connected, to deliver equal volume) might work, but if you have that setup and there's any uneven wear the volumes won't be equal. If one of those PD pumps has a seal leak you could enjoy seeing one ram with full pressure, and the other gradually losing pressure, and you'd get to watch the rams bend your frame and probably break your dieset.

So hooking up the hydraulic fluid input to the rams in parallel only works if the load is exactly centered. Hooking up parallel positive displacement gear pumps to get the same volume to each ram only works if the pumps are exactly alike, and can fail fairly catastrophically if a pump seal leaks. I don't think that either "exactly" scenario is likely.

The Beckwood designs use a sophisticated servo feedback control to ensure that all rams extend by the same amount and move the same distance. I suspect that they use position sensors on each ram, with a control system that includes diverter valves to pump more fluid to the ram that isn't extending as far.

I'm a control system engineer and, given enough time and money, I'd love designing, building, and testing a multi-ram press control system. That would really interesting. If I needed such a press and only had the money, I'd buy one from Beckwood. But for a one-off press I'd just go with a bigger ram. The "savings" from using different rams from different machines, and only using as many rams as you need would require some serious engineering, and a serious investment in sensors, valving, and control systems, to be workable. By the time you got a workable syste, I suspect your "savings" would have evaporated. IMHO, but YMMV.

It's interesting to think about this stuff and I admire the out-of-the-box design thinking.

Good luck.

With any press you need a suitable guide which is typically not just the rod gland bushing in a cylinder....

The issues raised above with parallel cylinders are very valid.

For a small area you describe I would just go bigger on a single cylinder.

Why try to reinvent the wheel???, just use 1 portapower cly of the tons needed and build it ...No fancy hydro system...I have built a few press,s and simple is the best...Phil

Phil in Montana said:

Why try to reinvent the wheel???, just use 1 portapower cly of the tons needed and build it ...No fancy hydro system...I have built a few press,s and simple is the best...Phil

Click to expand...

OP mentioned "bottle jacks"....enerpac cylinder & pump is 10x more money.

Not if you know where to shop...Phil

Please take careful notice of the word "yawning" in their write-up.

And of the size and positioning of the two "posts" which are actually vertical, sliding bearings that GUIDE the moving element. Those two posts are absolutely essential to the proper operation of that press. Without them, it will quickly yaw or twist and you would end up with a pile of twisted metal.

Not to mention high pressure hydraulic fluid spraying all around your shop. Quite possibly THROUGH the press operator.

So, do I see any problems? Well, YES! And the very fact that you had to ask the question strongly suggests to me that you are NOT qualified to design such a press.

For Pete's sake, just buy another cylinder. One large enough to do the job by itself.

digger doug said:

2-Post Presses | 2 Column Presses | Cost Efficient Presses

Click to expand...

Phil in Montana said:

Not if you know where to shop...Phil

Click to expand...

Please enlighten us.....