Electric powered hydraulic cylinder ?

[bcarwell]

Hi folks,
I'm considering building a bucket grapple for my Kubota 7500 FEL and have been looking at various designs and means for powering the grapple.
One interesting thing I ran across is an "electric powered hydraulic cylinder". The neat benefits are the hydraulic circuit is all self contained and doesn't need to be tied into your tractor hydraulics, need to get a hydraulic valve, etc. The grapple direction switching is a mere DPDT switch easily mounted on your dash and the cylinder is powered off your tractor battery- no hydraulic hoses. The grapple (and video showing operation) may be seen at - Extreme Metal Products, LLC
Several questions though: 1) where do you find such "electric powered hydraulic cylinders" ? 2) what are the drawbacks to them over a regular hydraulic cylinder ? 2) Are they significantly weaker than a regular hydraulic cylinder ? When watching the demo video it is hard to see how much "crunching" or "gripping" power the grapple is capable of exerting when closing down on a pile of brush.
Especially I'd like to know some sources of these electric powered hydraulic cylinders to read up on them.
Thanks for any input.

Bob

 

[beenthere]

Crunching down on a pile of brush in your bucket or on your forks may not be what is needed. Dropping a grapple finger, or two, down to just hold that pile of brush may be all that is really needed. At least, that is how I envision using such a holding device.

Surplus Center may be a place to look for this product.

 

[Hooked_on_HP]

are you talking about a linier actuator? If so there is nothing hydraulic about it. It is basicly a screw. the motor turns the screw making it extend or retract. It has nowhere near the power of a hydraulic cyl. If you look on SC's site the strongest one they have has 500lbs of power. You will lose a lot of that power in the leverage of the grapple.
Bill

 

[IceStationZebra]

I have seen them, but I don't think they are very fast. I think Gehl uses one on their powered skid-steer quick attach. Unfortunately I don't remember who made them.

ISZ

 

[bcarwell]

Thanks all for responding.

Good points about these actuators not being fast or powerful and loss of power from the grapple leverage. But if you look at the video of the grapple bucket in action at the website I mentioned, it looks like they are adequate.

However its hard to tell from the video if it could hold a boulder or tree stump adequately. I am not trying to compress brush piles but a little holding power would be nice. Trouble is I'm clueless what the necessary power is- 300 lbs or 600 or ...

And to be clear these are NOT the worm gear electrical linear actuators like you see on Gators dumping the dump bed. They are electro-hydraulic but I'm not exactly sure how they work- apparently the electricity somehow develops hydraulic fluid pressure delivered to a normal hyraulic cylinder so you get the force multiplication by the hyraulics principle. So presumably they are more powerful than an electrical worm gear type actuator. But very compact and don't require hydraulic hoses to your tractor hydraulic aux and don't require hydraulic control valves but rather just a DPDT electrical switch easily mounted on your tractor dash. Seems very cool and simple.

But again the biggest problem is I can't seem to locate any source for them to read about.

 

[aczlan]

are you talking about a linier actuator? If so there is nothing hydraulic about it. It is basicly a screw. the motor turns the screw making it extend or retract. It has nowhere near the power of a hydraulic cyl. If you look on SC's site the strongest one they have has 500lbs of power. You will lose a lot of that power in the leverage of the grapple.
Bill

The one he is referencing appears to be a electric motor, hyd pump and cylinder in one unit: http://www.extrememetalproducts.com/images/Grapple4_small.jpg
One thing that they dont show are the wires going to it. Those will need to be decent sized and if you are thinking of using it often I would recommend upgrading your alternator to handle the extra current draw.

I would think that a electric over hydraulic selector valve on the curl circuit and a ram would be less problematic... but it is up to you.

Aaron Z

 

[oldnslo]

Aaron Z is correct in saying that these draw lots of amps. Company i work for builds DC power units and they pull 250 - 350 Amps. We do NOT make complete assemblies like what you are looking for though.

Possible companies that make these are:

SPX Fluid power: formerly OMC power Team located in Rockford, IL

Enerpac: located by Milwaukee, WI

Since you are in Texas I don't know if you have truck mounted snow plows but they are and example of self contained units.

Roy

 

[beenthere]

The one he is referencing appears to be a electric motor, hyd pump and cylinder in one unit: http://www.extrememetalproducts.com/images/Grapple4_small.jpg
One thing that they dont show are the wires going to it. Those will need to be decent sized and if you are thinking of using it often I would recommend upgrading your alternator to handle the extra current draw.

I would think that a electric over hydraulic selector valve on the curl circuit and a ram would be less problematic... but it is up to you.

Aaron Z

Sub the numbers 2 and 3 in the mentioned url (replacing the 4) to get a couple more pics of this product. The other pics show the cable wiring going to the unit. Looks out of place on that bucket, and looks like the length of throw is a bit shy, however it does show the unit.

 

[beenthere]

Googling "electric hydraulic cylinders" will get several hits.

One is
API Marine - Hydro-Hatch Lift System

There are others.

 

[aczlan]

Sub the numbers 2 and 3 in the mentioned url (replacing the 4) to get a couple more pics of this product. The other pics show the cable wiring going to the unit. Looks out of place on that bucket, and looks like the length of throw is a bit shy, however it does show the unit.

I see that now. I dont think you will get much "Oomph" out of that unit with those wires unless it is painfully slow. They are only 12ga at best whereas most plow pumps use 6 to 2 gauge wire. As such you will not have any force to speak of OR it will get the force by gearing the pump down which will make it very slow. If you want to look into that unit I would ask what the full open to full close cycle times are.

I would recommend getting (or making) something like one of these: Valve Kits instead it will be a much better choice in the long run.
For hours of entertainment you can also see site:tractorbynet.com electric over hydraulic selector valve or site:tractorbynet.com 3rd function valve and read the various threads that have been started on the subject.

Aaron Z

 

[AKKAMAAN]

Aaron Z is correct in saying that these draw lots of amps. Company i work for builds DC power units and they pull 250 - 350 Amps. We do NOT make complete assemblies like what you are looking for though.

"Pulled" amps will be proportional to the load on the cyl, or the hydraulic pressure....so 250-350A will be when cylinder stalls for relif valve by pass. Just moving unloaded cyl should only take a smaller portion of the max amps......
how about using a smaller power unit, and a small size starter battery as an accumulator for the high Amps.....will need a high amp relay too....fram a starter motor.....

 

[IceStationZebra]

I just ran across one supplier of these - Kayaba out of Japan. Check out the catalog on their web page. They have models up to 2600lbs of force and 6-14" of stroke.

www-dot-kybfluidpower.com/Mini_Motion_Package.html

ISZ

 

[killdozerd11]

Hi folks,
I'm considering building a bucket grapple for my Kubota 7500 FEL and have been looking at various designs and means for powering the grapple.
One interesting thing I ran across is an "electric powered hydraulic cylinder". The neat benefits are the hydraulic circuit is all self contained and doesn't need to be tied into your tractor hydraulics, need to get a hydraulic valve, etc. The grapple direction switching is a mere DPDT switch easily mounted on your dash and the cylinder is powered off your tractor battery- no hydraulic hoses. The grapple (and video showing operation) may be seen at - Extreme Metal Products, LLC
Several questions though: 1) where do you find such "electric powered hydraulic cylinders" ? 2) what are the drawbacks to them over a regular hydraulic cylinder ? 2) Are they significantly weaker than a regular hydraulic cylinder ? When watching the demo video it is hard to see how much "crunching" or "gripping" power the grapple is capable of exerting when closing down on a pile of brush.
Especially I'd like to know some sources of these electric powered hydraulic cylinders to read up on them.
Thanks for any input.

Bob

I watched the video and for a home owner it might be ok but for serious work i don't know.The guy was going slow for the demonstration but it didn't seem fast or powerful

You can use an electrical servo valve to control the hydraulics for the grapple or thumb

the only other electrical hydraulic system i am familiar with is a unit that has a tank and a pump run with an electric motor they are used for presses
and benders,punches and lifting and holding devices.
they are mostly low GPM pumps so are not very fast in general.

 

[tommu56]

google

electric linear actuators

305,000 hits

Linear Actuators, Linear Motors, Micro motors, Electric Motors

Warner Electric New Products

a couple that I'm familiar with

tom

 

[Gary Fowler]

I cant imagine a battery powered pump putting out a lot of gallons per minute. Even the 120 volt ones I have seen are really slow. I would bet that this 12 volt one would be so slow that you would be impatient to wait for it to close the grapple especially if it developed 1500-2000 psi pressures.

 

[bcarwell]

I hear y'all about the amount of power being suspect. But the grapple I saw it on (at the website I noted) was priced at $1200+. If it is weak I'm sure they're gonna have a lot of mighty disappointed customers ! The only other place I'd seen them was in marine applications but that was just to open some pissant hatches and other light work. They sure seemed nifty though and perhaps I'll keep it in mind for other applications. And I never did cost it out versus conventional hydraulic cylinders.

Bob

 

[bcarwell]

Tommu56- it looks like those (Warner, etc.) are just electrically driven linear actuators with worm gears or whatever. The one I'm talking about is electro-HYDRAULIC. It's the "hydraulic" that caught my eye unless its false advertising. I wondered how on earth they could fit an electrically driven hydraulic pump, fluid, etc. all in the space of what looked like a regular hydraulic cylinderer. Still don't know how these things work and what's in them. Maybe there's info at Kayaba. Thanks for the hotlinks though as I'm sure I'll need an electrical actuator some day too...