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?

 

[LD1]

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.

Huge difference between a snowplow and a rear blade.

If the rear blade is going to see dirt, even 1% of the time as the op suggests, a 2" cylinder is NOT going to be enough.

And a snowplow is NOT rigid like a blade. It has trip srpings to absorb/cushion things like curbs, or catching sod at the edge of the drive.

 

[wvpolekat]

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

I live out Brushy Fork, past Stony Run.

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?

I can spin my blade 360 degrees without hitting the tires, so clearance isn't an issue.

The biggest reason for the difference is where the cylinder mounts to the blade. When you turn the blade around, it ends up further from the cylinder mount. Hard to put into words.

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

The blade rotates on the 3ph frame on a 6" or so tube. The blade and "locking plate" where the pin goes and the cylinder would mount move up and down about 1/2" between when it is resting on the ground and hanging in the air. It has been like this since new and doesn't effect normal operation, but if I cylinder were mounted, it would pull it down that 1/2" when the blade was lifted, which I believe would make the cylinder unhappy and put a lot of stress on the mounts.

At the end of the day, I see me doing very little dirt work with it, and if I do, I can still drop the pin in and lock out the hydraulics. I am doing this to make snow clearing easier, and I just can't justify basically doubling the cost of the project for a worst case scenario. My road and drive are both well above the surrounding ground, so the likelyhood of my catching on something is fairly small.

A cushion valve would add $65 to the project and protect the cylinder, mounts and hoses. I would worry as much if not more about the mounts breaking more than bursting a hose. If it kicks in, it's time to drop the pin in. Pretty easy solution and keeps me from having to purchase and find space for a 2x larger cylinder and associated mounts.

 

[cmhyland]

While a Rear Blade may build up large forces on a cylinder ... I've hit rocks plowing at high speed... the kind of speed you'd never see moving dirt with a rear blade and had no problems but, I've looked at Landprides 96 inch power angle rear blade and it uses a 3.5
x1.5 cylinder... So I stand corrected...

 

[LD1]

I live out Brushy Fork, past Stony Run.



I can spin my blade 360 degrees without hitting the tires, so clearance isn't an issue.

The biggest reason for the difference is where the cylinder mounts to the blade. When you turn the blade around, it ends up further from the cylinder mount. Hard to put into words.



The blade rotates on the 3ph frame on a 6" or so tube. The blade and "locking plate" where the pin goes and the cylinder would mount move up and down about 1/2" between when it is resting on the ground and hanging in the air. It has been like this since new and doesn't effect normal operation, but if I cylinder were mounted, it would pull it down that 1/2" when the blade was lifted, which I believe would make the cylinder unhappy and put a lot of stress on the mounts.

At the end of the day, I see me doing very little dirt work with it, and if I do, I can still drop the pin in and lock out the hydraulics. I am doing this to make snow clearing easier, and I just can't justify basically doubling the cost of the project for a worst case scenario. My road and drive are both well above the surrounding ground, so the likelyhood of my catching on something is fairly small.

A cushion valve would add $65 to the project and protect the cylinder, mounts and hoses. I would worry as much if not more about the mounts breaking more than bursting a hose. If it kicks in, it's time to drop the pin in. Pretty easy solution and keeps me from having to purchase and find space for a 2x larger cylinder and associated mounts.

Hey, its your project and your money. But a $96 cylinder and a $65 cushion valve is $160. So you are only saving ~$16 by doing that vs just going with the 3" cylinder and being done with it. ANd it will be a less complicated to plumb in IMO.

But how much are you really going to save if you find out the hard way that the 1.5" cylinder is not big enough????

 

[wvpolekat]

But how much are you really going to save if you find out the hard way that the 1.5" cylinder is not big enough????

Good point. Just trying to rationalize a way to do this without putting a big honkin *** cylinder on it.

I am going to have to do some figuring on the mounts as well. My original plan was to just weld a 1" pin vertically and drop the cylinder over it. But, I suspect that won't cut it with the forces we are talking.

Let me get my notepad out and do some doodling. The mount pins will obviously have to be vertical, so I will have to come up with an arrangement where I can get to both top and bottom and have enough support to not rip it off of there.

I think I can come up with something. May have to find a local machine shop to bore the holes so they line up and such. No drill press here.

Would reinforcement be required around the holes if I went with say 3/8 plate for the bracket? That would mean a total of 7/8" of material in contact with the pin.

 

[LD1]

Good point. Just trying to rationalize a way to do this without putting a big honkin *** cylinder on it.

I am going to have to do some figuring on the mounts as well. My original plan was to just weld a 1" pin vertically and drop the cylinder over it. But, I suspect that won't cut it with the forces we are talking.

Let me get my notepad out and do some doodling. The mount pins will obviously have to be vertical, so I will have to come up with an arrangement where I can get to both top and bottom and have enough support to not rip it off of there.

I think I can come up with something. May have to find a local machine shop to bore the holes so they line up and such. No drill press here.

Would reinforcement be required around the holes if I went with say 3/8 plate for the bracket? That would mean a total of 7/8" of material in contact with the pin.

3/8" plate on both ends should be pleanty even for a 3" cylinder. And a 3" cylinder really isnt that big. I would personally suggest looking at the way chilly807 did his in the like I posted.

 

[wvpolekat]

3/8" plate on both ends should be pleanty even for a 3" cylinder. And a 3" cylinder really isnt that big. I would personally suggest looking at the way chilly807 did his in the like I posted.

I will need to take a picture of mine, but it is made different and wont require the post. I can attach directly to the indexing plate.

 

[Baby Grand]

Good point. Just trying to rationalize a way to do this without putting a big honkin *** cylinder on it.

QUOTE]

I have been dithering over this idea myself. Very frustrating.

First thought I had: if you look at the existing adjustment (lock pin & holes) you should be able to back into the "designed-to" load by calculating the shear capacity of either the pin or the plate with the holes in it.

Second thought: use whatever size cylinder you need to move the blade and use a separate solenoid or hydraulically actuated lock pin to secure it for loaded use. This makes the cylinder size independent of operating loads. Not an ideal solution, but might take some of the risk (and cost) out of spec-ing the cylinder. It might be possible to rig it so the lock pin releases anytime the cylinder actuates, simplifying operation and reducing the chance of overloading the cylinder or pinned joint.

-Jim

 

[nspec]

While I don't doubt there is quite a bit of force on the hydraulic cylinder, I think we are all discounting the fact that a lot of the force gets absorbed by the kingpin before it actually gets to the cylinder. Look at the length and size of the loader and backhoe cylinders on some of the small tractors - they're tiny!

I think the hydraulic lock pin is an excellent idea, but I would try to make a mechanical locking pin with a linkage and a rod that you could pull from the tractor seat. That would be really slick. You could leave it unlocked most of the time and lock it up for heavy work.

We used to have a large New Holland corn chopper that had a linkage you would release to 'open up' the hitch from the road/transport to the field position. I think the baler was like this too. The linkage was spring loaded to keep it locked, and you pulled a piece of baling twine that was routed up the hitch (through support eyes) parallel to the hydraulic hoses and the pto shafting. We would be able to reach out the back window of the tractor - full size tractor - like 150 hp, so it'll work on the small ones just fine.

 

[LD1]

While I don't doubt there is quite a bit of force on the hydraulic cylinder, I think we are all discounting the fact that a lot of the force gets absorbed by the kingpin before it actually gets to the cylinder. Look at the length and size of the loader and backhoe cylinders on some of the small tractors - they're tiny!

Their is going to be almost NO force absorbed by the kingpin. If it were not for the cylinder, their would be NOTHING stopping the blade from spinning if one side has more resistance than the other.

Loader and backhoe cylinders are a different geometry. With a backhoe, their is nothing acting back on the cylinder (Tractor is not pulling aginst the cylinder). And with a loader, their are two cylinders in each circuit, not one. And in the case of the lift cylinders, if you are digging with the FEL, their are two forces. One pushing back on the tractor trying to collapse the cylinders, and a downward force. That is why the front end of the tractor will raise into the air.

In the curl circuit, if you have the bucket dumped and are backdragging, this is similar to the blade situation. Cutting edge in direct contact with the ground, tractor applying force, and the only thing keeping the bucket from curling back up is the cylinders. I am probabally not the only member on here who has blown a curl hose doing this exact same thing. And thats with TWO cylinders @ 1.77" EACH.

It really is not that hard to figure out. Unless the OP has a VERY SMALL tractor like a BX kubota or similar SCUT, a 1.5" or 2" cylinder simply isnt going to work. But hey, if you want to find out the hard way, go for it. But I am one that can learn from someone elses mistake and not repete their failure. Chilly807 in the link I gave already tried this with a 2" cylinder. He overextended the cylinder and bent the rod. And he only has a L3400 like myself. Which is on the smaller/lighter side of a CUT.