Snow plow angle valve

[jthaxter]

Man, this setup is so hokey I'm embarrassed to show it. But anyway, here it is. The plow frame had been modified by some previous owner, so I just extended it to the tractor and used a couple of pins for attachment and lift swivel. I had to make the setup the day before a big storm, so there wasn't a lot of engineering put into it. I figured I'd change it later - but it's still working, so I've never bothered.

 

[J_J]

On the cross over valve statement, there is no relief to tank. It is there to take the shock pressure, and dump to the other side, as long as the relief pressure is exceeded.

The cyl limits are dictated by the amount of fluid in the rod end. If you dump the rod end fluid to the base end, the cyl rod will not be extended to max. So therefore, I believe the cyl max angles will not be equal. Not a big deal though.

 

[J_J]

The crossover valve does not have a tank port. It just transfers to the other side of the cyl.

The max angle will be dictated by the amount of fluid in the rod end, therefore stroke extension. The angles will not be equal because of the amount of fluid in the rod end will not fully extend the base end cyl stroke.

Also, max angle will be limited to where the cyl is mounted relative to the baseline of the blade. If the cyl is close in to the pivot point, you will have more angle and faster operation.

 

[Leejohn]

Did you use the plow when the storm came in?

 

[LD1]

On the cross over valve statement, there is no relief to tank. It is there to take the shock pressure, and dump to the other side, as long as the relief pressure is exceeded.

The cyl limits are dictated by the amount of fluid in the rod end. If you dump the rod end fluid to the base end, the cyl rod will not be extended to max. So therefore, I believe the cyl max angles will not be equal. Not a big deal though.

If the rod is extended, there is more volume in the base of the cylinder. And since there is already fluid in the rod side, if you force the cylinder to collapse, and the base end fluid tries to enter the rod side, there is no room for it:confused2:

I guess I am a little confused as to how it is supposed to operate then. I can see it absorbing some shock, but as a crossover????

 

[jthaxter]

Been using the plow for two years now. I figured "this thing isn't going to last", but it has. That very first storm was a foot of wet, heavy snow, and the rig handled it just fine. I'm more surprised than most. It's also nice that the plow can be raised quite high to push the tops of snowbanks back.

 

[J_J]

If the force on the plow pushes on the cyl with enough force, the mechanical action will force the rod to either extend or collapse, forcing fluid from one side of the cyl to the other side, through the relief valve .

If the cyl is half way out, there is some fluid in the base end, and there is less fluid in the rod end.

 

[LD1]

If the force on the plow pushes on the cyl with enough force, the mechanical action will force the rod to either extend or collapse, forcing fluid from one side of the cyl to the other side, through the relief valve .

If the cyl is half way out, there is some fluid in the base end, and there is less fluid in the rod end.

If the cylinder is half way out (or any distance out for that matter)....

And the plow catches something that will force the rod to collapse......

There is a greater volume of fluid being displaced on the base end than there is room for on the rod end.

Quick example:

Cylinder has to collapse 2" due to object being struck.

That will displace say 20 ounces of fluid on the base side, but that 2" it collapsed only made room for 15 ounces of fluid. So where does the rest go?

IF you had a hydraulic cylinder and took OUT the piston seals, and filled EVERYTHING with fluid so there was NO air in the system.....

And had the cylinder FULLY extended and the ports blocked (or even connected to each other for that matter), the cylinder will NOT collapse. Because the rod occupies area INSIDE the cylinder when it collapses. THAT fluid that it displaces has to go SOMEWHERE other than remain inside the cylinder curcuit.

That is why I was wondering if that cushion valve you linked had a return back to tank.