snow plow FEL protection

TimBuck2 · Jan 6, 2015

I have a FEL mounted, straight blade snow plow. I am planning my hydraulic set up to supply power to two single action cylinders to angle the plow.

I recall reading a post about a relief valve that can be added to system too allow the angle to move if you hit something hard wiith one side of the blade to keep from bending the FEL boom. Can't find the post.

Am I dreaming? If not, what type of valve is it, and how is it plumbed?

Thanks,

Tim

Rock knocker · Jan 6, 2015

I think they're called a cross over relief

SIMassey · Jan 7, 2015

TimBuck2 said:
I have a FEL mounted, straight blade snow plow. I am planning my hydraulic set up to supply power to two single action cylinders to angle the plow.

I recall reading a post about a relief valve that can be added to system too allow the angle to move if you hit something hard wiith one side of the blade to keep from bending the FEL boom. Can't find the post.

Am I dreaming? If not, what type of valve is it, and how is it plumbed?

Thanks,

Tim

Can't get tablet to show link. Thread is "is crossover relief valve important" by Bap. It's on page 11

kennyd · Jan 7, 2015

Yes, they are called crossover relief or cushion valves. Here is a TBN google of the term "crossover" that will show some good threads: Search Results - TractorByNet.com

Here is the thread referenced above: http://www.tractorbynet.com/forums/...lief-valve-important.html?highlight=Crossover

We sell one also, as do other vendors:

TimBuck2 · Jan 7, 2015

Very good gents, thank you.

Tim

PILOON · Jan 7, 2015

The way they work is that pressure created by the extended cylinder impacting a solid object forces open the preset valve and pushes the oil over to retracted (empty) cylinder.
It is not 100% as only the extended plow corner is protected, example plowing along a curb with fully angled blade and you catch the curb you are not protected on the retracted corner.
Naturally straight pushing both corners have 50% protection. (1/2 each cylinder travel) but none if blade makes a mid blade contact.

On a plow truck a crossover is almost a must due to higher speed plowing but given the much lower tractor speeds I question the value.
Naturally I assume the tractor blade has a trip mechanism of some sort.

LD1 · Jan 7, 2015

The crossover is designed to protect the hydraulics and not the plow. Thats what the trip springs are for.

So when fully angled and plowing along a curb with the retracted side of the plow, there is no danger to the hydraulics.

TimBuck2 · Jan 7, 2015

My interest in the crossover relief valve is to protect the FEL boom arms from being wracked, not to protect the plow.

The retracted edge of the plow presents a much shorter lever relative to the FEL boom compared to the extended edge of the plow. So hitting something with the extended edge puts a lot more torque on the boom arms compared to hitting something with the retracted edge, so I am not concerned about the latter.

The couple hundred extra $$ to potentially prevent wracking my FEL seems well worth it.

George2615 · Jan 8, 2015

TimBuck2 said:
My interest in the crossover relief valve is to protect the FEL boom arms from being wracked, not to protect the plow.

The retracted edge of the plow presents a much shorter lever relative to the FEL boom compared to the extended edge of the plow. So hitting something with the extended edge puts a lot more torque on the boom arms compared to hitting something with the retracted edge, so I am not concerned about the latter.

The couple hundred extra $$ to potentially prevent wracking my FEL seems well worth it.

Surplus Supply (and many other places) have the cross over relief valve at reasonable prices. <$100. I installed one on my PA plow setup and it works well. If the extended end of the plow hits something hard the valve poppet opens and lets the blade turn to minimize damage.