converting loader controls to snow plow controls

[lostcause]

I'm sure this has been asked and explained plenty, but I'm not familiar with all of the proper hydraulic terms and i'm betting that is why I can't find the answer I want. What I'm doing is adapting a snow plow to use on the front of my tractor. I intend to use the loader controls to operate it, and my original plan was to use a pair of double acting cylinders - one for up/down and one for left/right angle. If I can utilize an existing plow frame and a pair of single acting cylinders (which I already have) for the left/right angle it will be easier than having to fab a new mount and get a new double acting cylinder. The problem is that if I plumb these lines directly to my loader valve's curl function ports i'm pretty sure it won't work - I've read a little and there seems to be a consensus that there is a regen function that will not allow this valve to control two single acting cylinders. My question is how do I get around this?

For reference I have a John Deere 770 with a model 70 loader. I know that there exists a factory option to do exactly what I want to do, because it is sold on the model 380 plow. If you look it up you will see a small fixture on the center of the plow frame that is taking in the hydraulic lines from the loader valve and sending out two lines that will control the left/right angle of the blade. I assume that this is some sort of relief valve that allows one cylinder to extend under power and allows the opposite cylinder to dump the fluid back. My question is: Is there some sort of generic universal hydraulic valve that will do exactly what I want without having to get a proprietary part from the manufacturer? Does something thing like this exist in the agricultural or snow plowing world that I can easily find (and if so, what is it specifically called, since I'm hydraulically challenged)?

I know that it will be simple and relatively cheap to just use one double acting cylinder to do the task, but it will be a bit more elegant and involve less fabrication and butchering to do this the way I want, so I'm hoping there is a not-too-expensive option to do this.

 

[Rustyiron]

my original plan was to use a pair of double acting cylinders - one for up/down and one for left/right angle.

This confuses me, are you making a frame mount, or are you mounting it on the loader?
I like a fame mount myself but it is a bit more work. You can use your bucket function with (2) "normal" s/a plow cyls. for angling or for a single d/a cyl. Then your loader "lift" circuit for the plow lift cyl. If you are mounting it on your loader, that will do the plow lift.

 

[kennyd]

Your loader valve should only have regen in the first part of the throw to the right, so if you only move the joystick a bit everything should work fine with two SA cylinders, and as you wrote the 380 plow worked with that model.

The valve you see on the center of the 380 is called a "crossover relief valve" or CRV, also sometimes called a "cushion valve". We sell one on our website, as does a few other vendors.

 

[lostcause]

This confuses me, are you making a frame mount, or are you mounting it on the loader?
I like a fame mount myself but it is a bit more work. You can use your bucket function with (2) "normal" s/a plow cyls. for angling or for a single d/a cyl. Then your loader "lift" circuit for the plow lift cyl. If you are mounting it on your loader, that will do the plow lift.

I'm going to do a frame mount. If I were to do a loader mount I wouldn't add the left/right angle option since the loader is designed to pick up & down, and not necessarily be stressed left & right. Just my opinion, but I worry that the loader's frame isn't going to like me smacking into frozen snowbanks with the plow angled. It's not really that rugged and there's a lot of distance/leverage from a plow blade back to the loader pivots on the tractor. Also, if I did want to angle it I'd need to add another hydraulic circuit in order to angle it. Since I wanted the ability to angle the plow I figured the frame mounted option would be the better way to go. now it's just a matter of getting the plow & a-frame home and see what I have in the scrap pile to make the frame mount up.

Your loader valve should only have regen in the first part of the throw to the right, so if you only move the joystick a bit everything should work fine with two SA cylinders, and as you wrote the 380 plow worked with that model.

The valve you see on the center of the 380 is called a "crossover relief valve" or CRV, also sometimes called a "cushion valve". We sell one on our website, as does a few other vendors.

Yeah, I've still been reading and trying to figure this out, and I have come to the same conclusion too. The problem was that the first information I found specific to my loader/tractor had several people who seemingly were unable to make this work, so I assumed there was some missing element that I needed. This just set me on the wrong path altogether. I have since found some other information that is in line with what you said.

 

[Rustyiron]

Last winter I did what you want, only with a V plow.
http://www.tractorbynet.com/forums/build-yourself/328941-frame-mount-snowplow-kubota-9540-a.html
I don't see why the "plumbing" would not work and as Kenny said, a CRV will protect things when you're smashing those banks back. It should be around $70. If your plow has the regular s/a cylinders, it is easy to plumb it in. I'm not sure how to add one to a d/a cyl. (you said that you had one) but I would think that you tie each end of the d/a cyl back into it. I made up hoses to extend the lines from where they have the CC couplers for the loader (factory location) down to the frame mount of the plow, then added another set of couplers so that the plow can be removed without pulling the long lines that get "zip tied" up and out of harms way for the whole season, leaving short lines on the plow. They are the ones that get beat up and being short, are cheaper to replace.