Pump from Bottle Jack

[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