Using implement where hydraulic piston has only one hose

[rjkobbeman]

Wouldn't this require a float detent to lower the dump? Some action needs to happen to allow the gravity to lower the dump. Pulling the lever to the "plugged B port" doesn't seem like the way to go (would that even work?). Putting the valve in the FD (Float) position would be a graceful way to lower the dump, no?

 

[AKKAMAAN]

I don't think so ... I may very well be wrong. Hook the single hose to the "up" remote. When you want to dump activate the lever and the cylinder will raise release the lever to the nuetral and the cylinder will "hold" activate again and up she goes ... put the lever in the "down" position and gravity will lower the dump.

Both my hay cutters have one hose cylinders ... this is excatly what I have done for years now ... no special valves. My pump or engine never labor ... Maybe I am missing something ???

Maybe you have a SA spool with out knowing it....LOL


If there is an adjustable work port relief valve in the plugged port, you can disable that pressure setting to almost zero....that will make it....

But when using a spool valve for double acting cylinder, pump flow will be directed to the plugged port, and wont have any ware else to go than through a relief valve , main or work port.....

UNLESS you are FEATHERING the control valve, then pump flow will go through the open center under a lower pressure...If your control valve then is rated for, a way higher flow, than pump flow, you will probably not notice any labor on pump or engine.....

But why buy a more expensive valve (over sized) control valve, instead of a less expensive properly sized valve with a SA spool.......

I do not oppose to "behind the barn engineering"....but I think the purpose with a forum is to put all "cards face up" before you make a decision, and after that you can decide do do what ever you want, and deal with the consequences.....

My 2c....

 

[blueriver]

Maybe you have a SA spool with out knowing it....LOL

If I do it came standard on both my tractors ... I have not made any adjustments, added any spools. I just hook up the one hose and go using it.

 

[J_J]

blueriver,

What you said is exactly how it will work. Instead of plugging the B port, you could run a hose off the B port to tank. If the lever is in the down position, the fluid just flows the B port to tank. The A port will drain the fluid from the cyl if the weight is sufficient.

 

[AKKAMAAN]

How SA spool works...

 

[AKKAMAAN]

blueriver,

What you said is exactly how it will work. Instead of plugging the B port, you could run a hose off the B port to tank. If the lever is in the down position, the fluid just flows the B port to tank. The A port will drain the fluid from the cyl if the weight is sufficient.

Oh I got what you meant now...little more back pressure and extra plumbing than using SA spool...... but I agree, that will work...
Thanks J_J....

 

[RickB]

You don't need all that extra stuff.
Your operator's manual gives instructions on turning an external bolt that opens a bypass valve that is internal to the remote valve slice. IIRC it takes a 10MM wrench. Open the bypass and you don't need any extra hose or plumbing, or need to stress your hyd pump by flowing excess flow over relief. RTFM.

A large single-acting cylinder may require more oil to fill than your reservoir can safely supply.

 

[audiski86]

RickB,

You are correct. In the Operator's Manual, I found a paragraph labeled, "Single/Double Acting Switching." It doesn't go into detail on how it works, but it says in order to switch control valves to: -Single Acting, loosen the screw 1, near the control valve lever pivot, until it stops. That seems like a convenient feature!

As far as the comment on using too much fluid to raise it making the reservoir low, i'm not sure how to tell if that would be the case. This is a 6500 lb tractor that is good size and the dump body is nothing huge, just a 10ft off a 1 ton truck. I think the guy said it was 2 stage telescopic. I suppose I could raise it up and check the fluid level, even if I had to have the level just a bit high when the dump is in the down position.

 

[RickB]

RickB,

You are correct. In the Operator's Manual, I found a paragraph labeled, "Single/Double Acting Switching." It doesn't go into detail on how it works, but it says in order to switch control valves to: -Single Acting, loosen the screw 1, near the control valve lever pivot, until it stops. That seems like a convenient feature!

As far as the comment on using too much fluid to raise it making the reservoir low, i'm not sure how to tell if that would be the case. This is a 6500 lb tractor that is good size and the dump body is nothing huge, just a 10ft off a 1 ton truck. I think the guy said it was 2 stage telescopic. I suppose I could raise it up and check the fluid level, even if I had to have the level just a bit high when the dump is in the down position.

Oil volume requirement may not be an issue. But it IS something to be aware of. I am quite familiar with your tractor model and also know that a good sized single acting telescopic cylinder can take a significant amount of oil to fill, possibly leaving an inadequate amount in the tractor. Checking the fluid level in the tractor with the cylinder extended is the best way to tell what is going on. You will have to use an alternative to the dipstick, as more than a couple gallons removed from the tractor will likely drop the oil level below the end of the actual dipstick.

 

[PILOON]

If all else fails, insert a 'T' in the pressure line and a ball valve from the 'T' back to reservoir, OPening the valve will lower the trailer.