How to Set Up Hydraulic Cylinders One After Another

The pressure should be the same in all cases, so if it is enough to push one spade into the ground, it should also be enough for three, though at only 1/3 the speed. Thus I would use just the one valve and connect the cylinders in parallel.

Sounds more like a tractor lift than a spade, if you try to plant all three blades at once.

In-line ball valves would work.

Amendment to my earlier reply: If the weight exerted by the tractor is greater than the combined cylinder force, the idea might still sort of work.

Tcmtech's strategy is better, though (GA); the two extra valves shouldn't be all that costly.

If you plumb them in parallel, the one with the least resistance will move first. The fluid will seek the path of least resistance. The spades will have a mind of their own. A simple valve rated for the max pressure of your system for each cylinder should do. You may only have to do this on the down line, if them coming up independently is ok. Otherwise, three separate double acting valves will be necessary.

ahh very good. So if for each cylinder, I downsized my hydraulic lines eg. 3/4 to 5/8, one cylinder (the one with the least resistance) should function first. Nice, and I don't have to add any extra valves

The logical way to plumb this, is to place all three cylinders in cascade series.

That way they all move at the same pace. This assumes the cylinders are double acting

I don't think you can plumb double acting cylinders in series. The rod area makes for a difference in swept volume of the cylinder when it reverses. You can't plumb the piston end of one to the rod end of another. Has to be a parallel circuit.

3 cylinders, pressure goes to A, the output goes to B, and the output of B goes to C. Each cylinder advances at the same rate. they can be reverse driven, or spring reversed.

Larger units would use metering valves. drill down a few of these, see if you can find online manuals that will advise.

Hydraulic Tree Spades

"pressure goes to A, the output goes to B, and the output of B goes to C", sounds to be good idea. But why should, "Each cylinder advances at the same rate (simultaneously?)". Why not one after the other such that the whole fluid force is available effectivly for one cylinder. If this agreable, a ball valve between A and B and another between B and C, open the them, one after the other, once the respective cylinder is done.

Once the shovels bite, they may be able to enter the earth, like a screw into wood, as long as they have enough penetration for this type of progression can work - much like a screw biting or stripping. That said, earth has mass, not strength in tension - as wood has - which allows screws to work?

Lyn says, you need independent action - which may be correct. Reading a use manual of an actual piece of equipment may clarify this aspect?

I am not sure of all brands of tractors that have power down three point hydraulics but our local tree farmer uses Belarus tractors for this reason. Check and see what commercial units use for hydraulic control of each spade if any. I would assume that the spade with least resistance would bottom out then the flow and pressure would be available for the next spade until they all were under the tree. I have also noticed that they could pulse or vibrate the spades to get to their destination quicker in difficult ground.

You MUST BE ABLE to control each spade separately. Period. End of story.

There's no other way to do it. You WILL lift the tractor off the ground otherwise.

U R looking for a flow divider,try this link to know more...http://m.hydraulicspneumatics.com/200/TechZone/HydraulicValves/Article/False/6410/TechZone-HydraulicValves

Hi,

Won't that circuit make all the cylinders go out (and back) together not in sequence?

Best regards,

John

Flow dividers are used to ensure that multiple cylinders move at same speed to each other providing each is same size and not leaking that would upset the balance. Flow divider not needed in this instance.