cross over relief for snow plow

[PILOON]

Are you saying that you dump from one cyl to another cyl.

A single SA cyl only has one side. The other side is air.

Yes JJ, that is how those valves work. In effect they are more or less specific to snow plow type operations.
It would be like having 2 SA cyls connected together with one single hose, the movement of one will be replicated by the other and in effect can replace throttle cables (bowden).
PRV's usually have 3 ports, in/out and 3rd return to reservoir. In case of crossover rather than to tank it dumps to other s/a pressure line hence only 4 ports.

 

[grsthegreat]

grsthegreat ,

You mean that you only have one cyl to push and let the ground force retract/close the cyl.

A relief valve can be set up on just about hyd cyl to protect that cyl, when the valve is in neutral.

No you do not need a double relief for a single action cyl.

Some valves have work port relief.

My BH bucket spool has double work port reliefs.

JJ, no i have a single double acting valve to run the snow blade. It powers to retract and powers to extend. I see that some plows have twin cylinders that oppose each other...and im not sure if there single or double acting.

i was wondering if they make a cushion valve for a single double acting system

thanks

 

[RickB]

I have always wondered, but how well do they work on a single DA cylinder due to the difference in volumes of fluid between the rod side and the base side? I just assumed they wouldnt work well at all??

They work a whole lot better than not having one at all. Designing a plow with one double acting cylinder is a cost cutting deal. Dual single acting is a better design and used by most mainstream plow builders.

 

[glastron23]

you definitely need a cross over on the plow cylinders, a short curb and your looking for hoses.. cylinders ... blades ... loader arms... etc.. i use these units.. CRV08-20 Hydraulic Pressure Control Valve Jim
getting advice for snow plows from Florida is like getting advice for sunscreen from some one in Alaska!!! LOL

 

[Deerherd]

i was wondering if they make a cushion valve for a single double acting system

thanks

Here's a picture of my old HLA plow showing a cushion valve on an angled single cylinder. (It worked great and kept the blade closer to the tractor)

It looks like the same valve on my new plow, which is a dual cylinder. (second photo)

 

[grsthegreat]

Here's a picture of my old HLA plow showing a cushion valve on an angled single cylinder. (It worked great and kept the blade closer to the tractor)

It looks like the same valve on my new plow, which is a dual cylinder. (second photo)

View attachment 365137

View attachment 365138

ah... ok now i see whats involved. i can add something like that easily. And i do see how that would be cheap insurance for my expensive plow and loader.

 

[glastron23]

nice pic of a twin dual acting cylinder set up..

 

[LD1]

Come to think of it, my backhoe has a cushion valve similar to that second plow with 2 DA cylinders. To protect the lines when you have a heavy scoop and are swinging and go to stop. Without the valve, all of that energy has to be absorbed by the lines when the valve slams closed. The cushion protects that.

Not saying it don't help, but certainly works better with two cylinders as opposed to a single DA. Cause fluid volumes are equal with 2 cylinders.

 

[vtsnowedin]

you definitely need a cross over on the plow cylinders, a short curb and your looking for hoses.. cylinders ... blades ... loader arms... etc.. i use these units.. CRV08-20 Hydraulic Pressure Control Valve Jim
getting advice for snow plows from Florida is like getting advice for sunscreen from some one in Alaska!!! LOL

You don't think that anybody that made their living plowing snow ever retired to Florida?

 

[vtsnowedin]

View attachment 365138

I had to look at that setup a while to trace out what was going on with it. That must be a very snappy swing if any real volume comes in from the main pump.