Manual control of flow and positioning

[DieselBound]

Pretty sure that this has been discussed somewhere, but I can't seem to find the proper wording to search by...

I have a possible need to operate an hydraulic system by hand. That is, manually operate flow control while also manually repositioning the equipment. The exact need/case is a flail mower off the back of a tractor that doesn't have the capacity to provide hydraulic flow (without a huge expense) to the flail's positioning cylinder.

I'm thinking that I can plumb together two hydraulic lines using a simple ball valve. The valve would be opened up in order to reposition the equipment, and then closed to lock in its positioning. Would I be correct in assuming that this doesn't present any issues?

Perhaps the bigger concern/unknown is whether I could expect to be able to do this with my real world application of a flail hanging off the back of a tractor? It's not an adjustment that I'd be needing to do with any regularity. I am thinking that my only real issue would be whether I could physically (via manual manipulation) overcome the frictional forces of the flail. Perhaps just use my other tractor to reposition.

I'm doing mental gymnastics on this because a flail with hydraulic offset provides me with the ability to center the flail behind the tractor: some flails w/o hydraulic offset have two different adjustable positions, but they don't tend to provide centering.

 

[LD1]

I am 100% confused.

You have a flail with hydraulic offset right?

Whats the need for ball valves and all that? What are you trying to do that simply hooking the offset cylinder to a rear remote wont accomplish?

 

[DieselBound]

As noted, the tractor -my B7800- does NOT have rear hydraulics. My query here is exploratory: I don't have a flail for this tractor; because the cost/hassle of outfitting the B7800 with rear hydraulics I'm looking for an alternate way of facilitating the use of a flail with hydraulic side shift. Adjustment/shifting would be done by hand (or, if I couldn't exert enough force to move the flail while hooked to the tractor I'd do it while unhooked and then hook it up to the tractor).

 

[LD1]

IF you dont have hydraulics on the tractor, the easiest way is to take the hydraulic cylinder and hoses off, and get a comparable extended/retracted length turnbuckle. Like a toplink or ratchet.

IF you dont need infinite adjustment possibilities, a simple tube in tube with some holes and a pin.

Another option, if you are only moving every once in awhile, get some hoses made up with some QD's and unhook loader hydraulics, hook up flail and position where you want, then unhook flail and hook loader back up.

 

[N2DFire]

The first problem to overcome with moving the offset manually is that the Extend side of the cylinder requires a larger volume of fluid than the Retract side (because of the piston rod) so connecting the two together would require some type of reservoir for the extra fluid when not fully extended.

Given that you state you would not adjust with any real frequency (and the assumption that you're really only looking for full offset, full retract and maybe?? a couple of positions in between & not infinity variable) - I would suggest removing the hydraulic cylinder and replace it with a collapsing pin-able linkage set-up.

Traditional screw links would be too slow & cumbersome to adjust esp for full travel, a screw jack like a trailer tongue jack would also work but again I think would be too slow.

It shouldn't be too hard to fabricate something from either round or square tubing and some flat plate to make your attachment brackets. Google Telescoping Tubing.



I have also been thinking about a "Ditch/Bank Flail Mower" that has both Hydraulic Tilt & Offset. It's going to cost me about $800 to add 2 factory rear remotes and this would be the only thing (except maybe a Top & Tilt) that I would ever use them for, so I have thought about just running four hoses off the loader control QD's to the rear for the mower. Maybe that's an option for you - run the offset from the Curl/Dump function of your loader control.


[Edit to add - This is what happens when I try to post from work and keep getting pulled away. As you can see me & LD1 think alike - he should probably be scared. ]

 

[DieselBound]

Yeah, I was thinking that having some couplers would allow me to hook up my other tractor to manipulate the shift.

So, would it or would it not be possible to manually push the carriage if one had an open valve (hoses connected together)? The thought is that I could do this manipulation with the flail unhooked from the tractor. I supposed I could try this with my grapple (which goes on my NX)!

The turnbuckle approach gives me something to think about- thanks!

 

[DieselBound]

Steve, that's the gotcha that I'd have missed! And thanks for the picture (which is probably what LD1 was eluding to).

I don't feel quite as dumb about asking these questions. And now I feel smarter!

 

[LD1]

If you were simply thinking about hooking the two ports of the cylinder together with a valve....no that wouldnt work due to different volumes.

IE, if you extend the cylinder fully, it will hold x amount of oil.

To retract fully, the amount would be x minus the volume of the cylinder rod that you are shoving into the cavity. So no, all the oil cannot simply bypass from one side to the other without a tank, and a more complex hydraulic valve.

And if the flail is easy enough to move manually, just use the collapsible tube setup.

 

[muddstopper]

I would probably use a selector valve, simply pull a lever and choose which hyd cyl I needed to control off the current loader valve.

 

[Jack Yuan]

Hi, my EFGCH flail mower cylinder ask for 16 MPa as minimum hydraulic output pressure, so check if your tractor hydraulic output pressure can reach 16MPa.

About the ball valve, you can use this kind ball valve.. The adapter size of flail mower hose is G1/2.