M7060 Hyd. Toplink

[sixdogs]

Six, you can add a lock valve to the cylinder, but you lose float.

I don't think I use float or even know exactly how it works. I can guess what a lock valve is but how does it work?

 

[ovrszd]

Not pimping these guys, just using them as an educational tool concerning a pilot control lock valve.

Prince Manufacturing Corporation > Products > Hydraulic Valves > Flow Control > Model RD14

 

[Fallon]

I don't think I use float or even know exactly how it works. I can guess what a lock valve is but how does it work?

There are cylinders with check valves on them. The valving box on the cylinder is locked shut until a large pressure is applied on either input, then it kicks open. So basically the cylinder can't move until it gets partial system pressure. Applying float at little to no pressure isn't enough to trip the valve.

Those valves add expense & complexity, not to mention kills float. They generally are needed to combat cheap spool valves on the tractor that let the cylinders leak down.

Float just opens both ends of the cylinder to the tank. The cylinder will extend & retract freely based what is pulling or pushing on the cylinder. I love it for mowing to keep the mower following the contours of the ground.

 

[olPete]

I have the cheapest flimsy toplink on my tractor and it easily handles a 3000 pound aerator without creeping. On 90hp. Sorry poor quality picture, I only had it for plumbing reference til I colour coded every QD with tape. My controls are wacky.. I have one spool that can lock in float, one that I can lock in constant pumping, and one that is single acting with a float position. Handy- but the tape means getting it right for each attachment/implement

 

[sixdogs]

This is a stupid question and I should know better, but how do I know if I have "float" on my hyd outlets? Would I merely push the hyd lever forward (or backwards) and if it stays there it has float? I use it for my bucket loader to grade things but never had much other use since I have draft control. Maybe I'm missing something here.

 

[olPete]

This is a stupid question and I should know better, but how do I know if I have "float" on my hyd outlets? Would I merely push the hyd lever forward (or backwards) and if it stays there it has float? I use it for my bucket loader to grade things but never had much other use since I have draft control. Maybe I'm missing something here.

Float is like a neutral. If you are in float then both ends of the cylinder are "dumped to tank" and the cylinder can move in or out as load takes it. Eg my FEL has a float position when i push the stick forward, a detent holds it there, and the loader goes to ground. I used the wrong term when i said i can lock it in float or constant pumping, it's a detent. Float is very useful for disconnecting and connecting, as the poppets in the couplings are free, reducing the effort it takes to plug one in under pressure. I use float on my mower so it can move, on my toplink so I can attach something with ease, etc

No such thing as a stupid question.

To see if your valves have a float pos. it's as you said, it should hold there; but it will sound the relief/safety valve while the system 'deadheads' (oil can't go anywhere but it's trying), but in float all the pressure is released. Put your 3pt hitch right down, and it is in float as it is a single acting system, no down pressure.

 

[ovrszd]

I'll add to Pete's offerings.

A non-cancelling, non-float valve handle always springs back to center. There are no detents on either end of the handle stroke.

A self-cancelling valve handle has detents on both ends of the stroke. I use mine when pulling my hydraulic lift wheeled disc. To raise the disc, pull handle rearward into the detent, when the cylinder reaches the end of it's stroke it kicks back to center on it's own. To lower the disc, push handle forward into detent, when the cylinder reaches the end of it's stroke it kicks back to center on it's own.

A float valve handle has a detent in the forward position (lower position) only. This puts the valve into "float" position and as explained allows the cylinder to freely extend/collapse. Pull back on the handle from center and it acts spring loaded like the first valve I described.

I have one SCV and two float valves on my Kubota. The Ford has two SCV valves.

 

[MtnViewRanch]

I'll add to Pete's offerings.

A non-cancelling, non-float valve handle always springs back to center. There are no detents on either end of the handle stroke.

A self-cancelling valve handle has detents on both ends of the stroke. I use mine when pulling my hydraulic lift wheeled disc. To raise the disc, pull handle rearward into the detent, when the cylinder reaches the end of it's stroke it kicks back to center on it's own. To lower the disc, push handle forward into detent, when the cylinder reaches the end of it's stroke it kicks back to center on it's own.

A float valve handle has a detent in the forward position (lower position) only. This puts the valve into "float" position and as explained allows the cylinder to freely extend/collapse. Pull back on the handle from center and it acts spring loaded like the first valve I described.

I have one SCV and two float valves on my Kubota. The Ford has two SCV valves.

If not to make things even more confusing, but I will add to Richards list.

Typically the 3 position spring return to center valve (let go of the lever and the lever always returns to center) is the most common type of valve and is the most common rear remote valve used on the majority of tractors talked about on TBN.

2nd, a very common valve used for rear remotes is a simple detent valve. This type of valve is intended to be used as a constant feed source for implements such as a log splitter. While these levers do not spring back to the center on their own, (pretty much stay where you leave the lever) they can be used to control a hydraulic cylinder if needed.

Different manufacturers supply different types of valves for their various tractors depending on what they feel the tractor is most likely to be used for. Some tractor manufacturers have valve options for you to choose from.

There are a lot of variables-options, that's for sure. :thumbsup:

 

[olPete]

They need a 'like' button on here!
Thanks for explaining that better, guys. I have one of each, and one that seems to have little or no reverse flow, that I use on my big tip trailer. Could just be an adjustment required to get it to behave.

 

[ovrszd]

Different manufacturers supply different types of valves for their various tractors depending on what they feel the tractor is most likely to be used for. Some tractor manufacturers have valve options for you to choose from.

There are a lot of variables-options, that's for sure. :thumbsup:

Yeah, if you use the "Build a Tractor" portion of Kubota's website, up in the larger Utility class, you choose which type of valving you want.

 

[ovrszd]

They need a 'like' button on here!
Thanks for explaining that better, guys. I have one of each, and one that seems to have little or no reverse flow, that I use on my big tip trailer. Could just be an adjustment required to get it to behave.

Most SCV valves are adjustable. The one on my Kubota works great using some implements, not so good on others. On my primary use it works great so I haven't tried to adjust. I'd just mess it up and then it wouldn't work where I use it most.

 

[JWR]

I don't think I use float or even know exactly how it works. I can guess what a lock valve is but how does it work?

It is like your front end loader -- push the stick beyond some point and it goes into float -- meaning the hydraulic cylinders are doing nothing and gravity has the bucket riding up and down with the terrain -- floating. I have never wanted that sort of behavior on hardly any of my applications (other than the FEL) and definitely not when using the hydraulic top link. I tend to detest control valves with detents that are constantly causing me to go into float when I had no such intentions. All that said, there might well be cases where hydraulic top link float would be desireable (??) . Note that 3pt lifts are inherently "float" in the sense that they provide only lift and not downward force.

 

[sixdogs]

Yeah, if you use the "Build a Tractor" portion of Kubota's website, up in the larger Utility class, you choose which type of valving you want.

How do most come from the factory and is there a way to tell what I've got by working the levers?

 

[JWR]

How do most come from the factory and is there a way to tell what I've got by working the levers?

Yeah, hook most anything to a remote and start up to pressurize the hydraulics. Then move the lever slowly forward and and it will go limp when it has gone into float. Usually some sort of "detent" feel to it. This is really a function of your control valves. If the control valves were there from the factory then the invoice details probably tell you. If they were dealer installed, ask them. The part numbers on the things may be nearly impossible to find/read, but they would tell you when looked-up.

 

[ovrszd]

How do most come from the factory and is there a way to tell what I've got by working the levers?

Most tractors come with an SCV valve of they only have one.

I explained in post #27 how to tell the difference by how the lever works.

This is very confusing until you get if figured out. Took me awhile.....

Look at my post #27 again and if you still don't get it we'll work thru it.

 

[sixdogs]

Most tractors come with an SCV valve of they only have one.

I explained in post #27 how to tell the difference by how the lever works.

This is very confusing until you get if figured out. Took me awhile.....

Look at my post #27 again and if you still don't get it we'll work thru it.

Thanks and I think I understand. I'll go out tomorrow and lookee see.