Pump from Bottle Jack

[yrralguthrie]

I need a small hand operated hydraulic pump. I realize the bottle jack is a pump, but I need to separate the cylinder from the pump.

If I drill and tap a fitting into the inner cylinder for the pressure side, drill and tap a fitting into the outer cylinder(jack body). Drill a clearance hole in the outer cylinder for the inner cylinder fitting. Put the jack back together, screw the inner fitting into it's cylinder through the clearance hole, I have a pump, correct?

If I allow the ram to bottom up, or take it out and weld the hole up, it should operate a cylinder?

Then to operate the remote double acting cylinder I will need a valve?


Have I overlooked anything? A little work, but much cheaper than the new hydraulic hand pumps I've been able to find. This project needs to go together cheap.

ljg

 

[DonnieP]

We called the hand hydraulic pumps 'porta-power', guess it's a brand name.

Porta-Power Hydraulic Ram Systems - JCWhitney

 

[kennyd]

Horrible Fright has them also: Search results for: 'portapower'

Enerpack has them also.


I think the main problem with the jack idea in reservoir capacity, plus they are not designed to operate DA cylinders.

What are you making?

 

[oldnslo]

I need a small hand operated hydraulic pump. I realize the bottle jack is a pump, but I need to separate the cylinder from the pump.

If I drill and tap a fitting into the inner cylinder for the pressure side, drill and tap a fitting into the outer cylinder(jack body). Drill a clearance hole in the outer cylinder for the inner cylinder fitting. Put the jack back together, screw the inner fitting into it's cylinder through the clearance hole, I have a pump, correct?

If I allow the ram to bottom up, or take it out and weld the hole up, it should operate a cylinder?

Then to operate the remote double acting cylinder I will need a valve?


Have I overlooked anything? A little work, but much cheaper than the new hydraulic hand pumps I've been able to find. This project needs to go together cheap.

ljg

How much oil volume are you trying to move? Bottle jack reservois are not very large.

Roy

 

[yrralguthrie]

I don't think any pump by itself will operate a double action cylinder. The flow has to be reversed and I've not seen a pump that reverses. All I've seen use a 5 way switch to reverse the flow to the cylinder. I intend to try to use a 5 way pneumatic switch. (cheaper)

I've seen all the hand pumps on Harbor Freight and others, for this project they are too big and way too much money. I need to move a ram about 3 inches with 500-700 lbs of force within about 1 second no faster. I have an operating model using an air cylinder, but the fingers have to be in the vicinity of the ram and an air cylinder operated way too fast with that kind of force. Also I need to be able to instantly stop the piston, which I can do with a hydraulic hand operated pump.

Oh...I forgot. The cylinder only has to operate the 3 inches with 700 lbs force so the volume of the double action cylinder can be quite low. The diameter of the cylinder less than 1/2 inch perhaps. That would require a hydraulic force of about 200-300 lbs. Within the capacity of a 2 ton bottle jack, which would be 2000 lb. per square inch.






ljg

 

[Iplayfarmer]

I don't think any pump by itself will operate a double action cylinder. The flow has to be reversed and I've not seen a pump that reverses. All I've seen use a 5 way switch to reverse the flow to the cylinder. I intend to try to use a 5 way pneumatic switch. (cheaper)

I've seen all the hand pumps on Harbor Freight and others, for this project they are too big and way too much money. I need to move a ram about 3 inches with 500-700 lbs of force within about 1 second no faster. I have an operating model using an air cylinder, but the fingers have to be in the vicinity of the ram and an air cylinder operated way too fast with that kind of force. Also I need to be able to instantly stop the piston, which I can do with a hydraulic hand operated pump.

Oh...I forgot. The cylinder only has to operate the 3 inches with 700 lbs force so the volume of the double action cylinder can be quite low. The diameter of the cylinder less than 1/2 inch perhaps. That would require a hydraulic force of about 200-300 lbs. Within the capacity of a 2 ton bottle jack, which would be 2000 lb. per square inch.






ljg

You lost me early on in the description of how to convert a bottle jack to a pump, but I can agree with you 100% that you'll need a valve. The only exception I've seen is a hydraulic pump for a convertible car. I have a pump from mustang convertible that is double acting.

 

[Mace Canute]

I need to move a ram about 3 inches with 500-700 lbs of force within about 1 second no faster.

I doubt a pump made from a hydraulic jack would have that amount of volume at that pressure even with a lot of modification.

Your math is wrong, btw.

Just a quick look at a hydraulic jack shows the piston is about or a shade smaller than the size your cylinder would be. For your application, lets say for simplicity's sake that they are the same size and we forget about efficiency. That means the piston will have to move the same distance as the cylinder and you will have to input the same force on the piston as you want to have the cylinder develop. That can be done with mechanical advantage. Lets say you have a 20:1 MA so you only have to input 35 lbs of force at the handle end. That means you have to move the end of your lever 60"...5 feet...because piston travel equals cylinder travel. 50 lbs at the handle would mean moving it 42"...3 1/2 feet. You would have to do this in the time frame of around 1 second and with a piston travel of 3". Even at 500 lbs at the cylinder and 50 lbs at the handle, the handle would still have to travel 30". Making the piston smaller would lessen the required input force but it would have to travel farther to make up the volume. A 3/8" piston would have to travel a third more to have the same volume.

 

[Iplayfarmer]

I doubt a pump made from a hydraulic jack would have that amount of volume at that pressure even with a lot of modification.

Your math is wrong, btw.

Just a quick look at a hydraulic jack shows the piston is about or a shade smaller than the size your cylinder would be. For your application, lets say for simplicity's sake that they are the same size and we forget about efficiency. That means the piston will have to move the same distance as the cylinder and you will have to input the same force on the piston as you want to have the cylinder develop. That can be done with mechanical advantage. Lets say you have a 20:1 MA so you only have to input 35 lbs of force at the handle end. That means you have to move the end of your lever 60"...5 feet...because piston travel equals cylinder travel. 50 lbs at the handle would mean moving it 42"...3 1/2 feet. You would have to do this in the time frame of around 1 second and with a piston travel of 3". Even at 500 lbs at the cylinder and 50 lbs at the handle, the handle would still have to travel 30". Making the piston smaller would lessen the required input force but it would have to travel farther to make up the volume. A 3/8" piston would have to travel a third more to have the same volume.

For that matter, no hand pump anything is going to move 700 pounds 3 inches in one second. That work is equivalent to 4 horsepower not counting any losses due to energy transfer. Assuming an average guy can curl 80 pounds, that's 9 pumps in a second if all of the pump ratios are perfect.

10 seconds is possible. 20-30 seconds is likely.

 

[evo803]

Look for a used pump that is used to operate the trim cylinders on a mercruiser sterndrive. They are very small , 8"x8"x10", electric ( 12v ), have a 2 pint reservoir, DA with rocker switch and certainly would be strong enough for your application.

 

[jbooth]

Common grease guns held in the vertical position will pump hydraulic oil just fine. Don't need the spring to force the oil as required with the grease. Some grease guns are advertised to pump as much as 10,000 PSI. I would think the higher volume guns which develop 2500-3000 pounds would be adequate.

 

[Skyco]

The port-power clone pumps are pretty inexpensive- $40 at NT-
Torin Big Red Hydraulic Ram Pump — 10-Ton Capacity, Model# T71101 | Rams + Ram Kits | Northern Tool + Equipment
I'm probably going to get one as a spare/extra for all my stuff that came in the kit of all the rams/pullers etc. might be a time when I need two pumps at once.
But as others said..trying to move 700 lbs 3 inches in one second will be very tough with a hand pump...

 

[J_J]

With your requirement of 700 lbs, and 1 second,

About the only to do that would be to pump up an accumulator, and use that force to activate the cyl through a closed center valve. Speed and pressure. Size of the accumulator will determine how many cycles of the cyl will occur.

 

[DanD78]

Why not use air to get the 700 lb force. A 3" cylinder will give you 706lb of force at 100 psi. It would be a lot cleaner to work with. You can also use smaller cylinders with different fulcrum points to compound the force.

Dan

 

[6011Artist]

Another idea is if you know anyone with any old cabover 18 wheelers, they have a seperate hydraulic pump and usually twin cylinders to raise/lower the cab. And they work under pressure going up or down. Cabovers are about obsolete, most use conventional cabs now, so the parts aren't really in demand, really not a market for resale, so the price shouldn't be that outragious.

Find an old truck, get the cylinders, hoses, pump, you've got a complete system, convert it to your application using 1 or both cylinders, you're in business.

 

[Bison]

^ I was thinking the same thing,a cab over jack

 

[yrralguthrie]

Mace Canute and I Play Farmer,

I hear you, but using your reasoning how does a 2 ton bottle jack move 1000 lbs. 4 in. in very much less than the low time you talk about?

I can easily pump a hand pump 4 times in 1 second. That's just 1/4 inch per pump. I think you are considering the mechanical advantage correctly, but don't understand the situation.

First of all I have a handle on the pump with a pivot. Say 2 inches to 16 inches. That's an 8 x advantage right there. So with a 20 pound force on the handle I have a 160 pound input to the pump. If I move the end of the handle 16 inches I have a movement of 2 inches. So the lever itself will move 160 pounds 2 inches with 20 pounds of input.

I know that is correct.

I need only a 4x (4x160) advantage from the pump to get to 720 pounds force out. That drops the movement of the ram from 2 inches to 1/2 inch per pump.

I also know this is correct.

Also I don't need to have 720 lbs./sq. in of force on the piston. I need 720 pounds of weight. The size of the piston is not material. Can be 1/2 inch or 2 inches. And before you get your drawers in a knot, what the ram is pushing on is what is important. A two inch piston pushing with 720 pounds on a 1/2 inch object applies the same force on the 1/2 object as a 1/2 inch piston pushing with 720 lbs. What this amounts to is that in my calculations I can ignore volume, except as concerns the total mechanical advantage.

So all I have to be concerned with is the total mechanical advantage to any size piston out.

So the hand pump only has to pump 1/4 the volume of fluid I displace with my 1/2 inch stroke. I'm unsure here, but looks like 8 pumps with the handle will get me the desired results. More like two seconds, but remember I said, no less than 1 second and more was ok.

My math before may have been incorrect, likely was, but not now.

ljg

 

[yrralguthrie]

I already addressed using air.

ljg

 

[yrralguthrie]

Mace Canute,

"I doubt a pump made from a hydraulic jack would have that amount of volume at that pressure even with a lot of modification."

A bottle jack is a hand pump with a SA piston. If a two ton bottle jack will lift 2000 lbs. 4 inches, why wouldn't it have enough volume to lift 700 lbs./3inches.

???????

 

[yrralguthrie]

THANKS, Skyco,

That does make sense.

I had looked at Northern Tools and failed to find that. Exactly what I need. The only ones I had found were $150 up...way up.

I will order one. I will have to manufacture a reservoir.

Now for those of you talking about volume. Why do I need much volume, or a big reservoir. What's the formula for the amount of fluid needed in the reservoir?

The closed system of a modified bottle jack is still interesting.

ljg

 

[yrralguthrie]

My math was likely wrong.

Your math as long as it goes is correct, but the advantage of a hydraulic system lies not the in length of the handle but the the difference is volume of fluid pumped each time. A 2 ton bottle jack wouldn't work at all using your math. In addition to the mechanical advantage of the handle there is also the mechanical (fluid) advantage of pumping a large amount of fluid to move a small amount of fluid and moving the handle a large number of times to accomplish this.

ljg