Making My Blade Power Angle

[wvpolekat]

So, I have decided that my next MUST HAVE is power angle for my rear blade. :thumbsup:

Took a measuring tape out today and made a scale drawing in Visio. Took that to start computing what length cylinder I will need.

Looks like a 10" stroke cylinder will give me 55 degrees one way, 40 degrees the other.

My current design will allow me to use the blade forward or backward by moving the cylinder from one side to the other. This will just require a second mount on the other side of the 3ph frame. I will not have as much range, only about 20 degrees either way, but that should be fine.

I will need to use a cylinder with ball ends since the blade has about 1/2" of vertical movement when it is put on the ground or lifted. Too much engineering work to make it have that much movement in a second plane. Also more work than I want to take the movement out of the blade.

I am going to use my grapple valve to control it. It has a switch mounted on the FEL joystick, so it is not as nice as having one next to me, but saves me a bunch of work as well as the cost of a valve. Also means I can't grapple and grade without switching the hoses. But, I can't see that being a real problem.

Because of the need for a swivel eye cylinder, there is a significant cost difference between a 1.5" bore cylinder and a 2" bore cylinder. About 50%. My calculations show that a 1.5" bore with 1" rod will produce 5298 lbs of pushing force and 2943 lbs of pulling force. This seems like plenty of force to adjust the blade in all but the worst conditions. Worst case, I have to lift the blade to adjust it. Still easier than climbing off.

Since the load will all be along the long axis of the cylinder (I believe), I feel that a 1.5" cylinder should be plenty. There should be very little side force on it.

Here is a rough, but to scale drawing:

Thoughts? Suggestions? Criticisms?

I will also use this as my build thread and should be starting on it later this week.

 

[LD1]

Thoughts? Suggestions? Criticisms?

Depending on how big your tractor is, I would say you need at least a 3" cylinder.

It doesnt take much force to angle the blade, but it does take considerable force to HOLD that angle.

You didnt give any measurments so I'll make some assumptions here and you can get the idea and make the final calculations.

So assuming you have a 6' blade, that makes it 36" from center to edge. And assuming your cylinder is mounted about 9" away from center, that is a 1:4 ratio. In the retract direction of the cylinder, that ~2900lbs of force translates into only 725lbs at the blade edge. That is not alot.

Imagine you grading and the edge of the blade gets a good bite and exerts say 1500lbs on that edge of the blade. Since there usually isnt a PRV after the controls, that would exert DOUBLE the operating PSI on your cylinders and hoses all the way back to the valve. NOT GOOD.

Their was another thread on here just about a month ago about a fellow member that ran into this problem with a 2" cylinder. It over-extended the cylinder and bent the rod if I rember correctly. He was re-doing it with a 3" cylinder. I'll see if I can find the thread.

 

[LD1]

Here it is.

http://www.tractorbynet.com/forums/welding/189597-adding-cylinder-mount-rear-blade.html

 

[wvpolekat]

Thanks for the math. The numbers are greater than I thought. I will have to price a cushion or prv vs a larger cylinder. 99% of my use is snow, with no curbs. Seems that a cushion or prv may be a good option. I do have a spare 2in cylinder, but the stroke is too short.

 

[LD1]

Not sure I entirly understand why you need the swivel eye cylinders.

Even clevis type cylinders will offer a little "play" in them. Is the blade pivots/swivels taht worn out??

Even if so, a 3x10 with swivels is only $176.

The 1.5x10 is $96 and the 2x10 is $127.

IMO, the 3x10 is going to be well worth the money. Even if you build in a cushion or PRV, you are going to want the cylinder to have enough force to HOLD the blade where you want it. The only thing a PVR gains you is it lets toe blade spin around instead of bursting a line. But still a PITA if you are trying to grade your drive or dirt and the blade wont stay where you want it.

https://www.surpluscenter.com/item.asp?item=9-7261-10&catname=hydraulic

 

[JB4310]

So, I have decided that my next MUST HAVE is power angle for my rear blade. :thumbsup:

Thoughts? Suggestions? Criticisms?

I will also use this as my build thread and should be starting on it later this week.

I'll be watching as I've thought about it myself for awhile, with my 6 FT RB mostly used for snow as well. I to would want it work with blade reversed, though I don't use it that way very often. Why can't it have the same range of movement?

I was thinking about the clevis types LD1 mentioned, they have them on the shelf at Tractor supply.

Imagine you grading and the edge of the blade gets a good bite and exerts say 1500lbs on that edge of the blade. Since there usually isnt a PRV after the controls, that would exert DOUBLE the operating PSI on your cylinders and hoses all the way back to the valve. NOT GOOD.

I never figured such a large cylinder would be needed.
This may be a dumb question but would it make any difference with one of those check valve cylinders that are so common now.

JB.

 

[LD1]

I never figured such a large cylinder would be needed.
This may be a dumb question but would it make any difference with one of those check valve cylinders that are so common now.

JB.

I am not sure exactally what cylinders you are talking about, But I dont think it is going to matter.

The blade has SIGNIFICANT mechanical advantage over the cylinder. And even small tractors are capable of generating a lot of force while pulling. That force has to go somehwere. That force trying to collapse or extend the cylinder is transfered into pressure in the system (PSI). The larger the cylinder, the more square inches, resulting in LESS PSI in the system. If you have TOO small of a cylinder, the PSI is very high. Either blowing the hydraulic lines, or if you install a PRV, it will open with little effort and the blade wont stay where you want.

Even if you have a checkvalve right at the cylinder, are you going to want to constantly have a force in that cylinder of 5000-6000+PSI if it is only rated @ 2500-3000psi????

 

[wrangler6831]

WVPOLECAT, Where in Buckhannon do you live? I live out on old 33 goiong toward weston. Near the stockyards. Just noticed your from Buckhannon.


Rich

 

[cmhyland]

When I added power angle to my 6' Meyers plow on my Kubota, I used a 2X8 cylinder. I can sweep the angle from one side to the other with any amount of snow piled up in front, and my blade is about 24 inches high.

You won't need anything more than that. Bigger is more expensive and harder to fit in the space you have.

 

[Argosy]

My father's blade has 3 adjustment holes each way. I won't use the ones that angle the blade the most because they put it so close to the tires. Have you checked clearance, 55 degrees is a lot of angle.

Why so much difference between the two swing angles?