Designing a LPGS

[bcp]

Another way to brace the top link post.
Priefert/ABI



Road Grader, Driveway Grader, Power Grader, Tractor Grader ::ABI Attachments::

Run the diagonal braces to the ends of the rear crossmember. Then leave out the center cross beam to avoid material catching on it, as some have mentioned.

Bruce

 

[Oliver1655]

Sounds like you are ready to weld. I have my cutters straight but the ones I looked at with angled blades had straight ends.

 

[aeblank]

Holy crap, no wonder the ABI one has bracing like that. It's 7.5' long.
I'm not too concerned about soil buildup in my situation, though I bumped the height up a couple inches for good measure.
I think I'll make a drawing and throw it at a local weld shop. We'll see.

 

[GPintheMitten]

"nobody" else has side supports on their top links, but I think I'll add some small gussets there and between the beams/skids.
Cat-3 pins makes sense. I'll put in the 7/8" pins and use bushings, since a quick-hitch shouldn't be a requirement.
I did see the mounts were plumb. I already changed that, but I haven't posted another picture.
I've pondered putting a SSQA plate on the back of it. We'll see.

You say nobody, but if you look closely at yhe Befco you linked to, it has them.

 

[davrow]

"nobody" else has side supports on their top links

My Landpride does. No central upright, but side supports yes.

 

[MtnViewRanch]

Holy crap, no wonder the ABI one has bracing like that. It's 7.5' long.
I'm not too concerned about soil buildup in my situation, though I bumped the height up a couple inches for good measure.
I think I'll make a drawing and throw it at a local weld shop. We'll see.

Mine is 8' long and cuts 84" wide, weighs 1400lbs. I think that it probably makes a little bit of difference with the material that is used to build the unit as to how much bracing is required.

 

[aeblank]

I don't see it. Looks like a bent flat stock frame bolted to angle iron "runners" (or I'm blind).
Guess I'm basing it mostly on the grademaster in combination with the land pride.
But anyway, I added some gussets here/there/everywhere.

I requested pricing on the ABI.

 

[jenkinsph]

I don't see the need for bracing a box tube post as you have drawn because the top link is free to move around. Where are the forces coming from that would demonstrate the need for these gussets?

 

[jwmorris]

If the rear of the device is lifted from either side, not both, it will try and twist the top link.

It is not that hard to calculate the force but you have to have more information.

Think about this. If you have something stuck and try to pull it with a chain connected to another "puller" then the tires spin on the "puller".

Say the chain is 50', if a person moves to the middle of the chain and steps on it with 100lbs of force. That action will pull both together as the force is multiplied by many times.

Think of it as a lever, if the chain is in tension 1ft off the ground and you move it to the ground by that foot (again in the middle) it will pull the two together by a very small amount with much more force than the 100lb applied.

Look at mowers that mount by a 3 pt, they pivot by the force the top link has if loaded at the rear.

 

[jenkinsph]

960lbs as it stands. I'm in the right neck of the woods.
Would love some beam size confirmations.
6"x6"x3/4" angle for the blade supports, as suggested.

3/8" side walls?
3/8" skid shoes/wraparound?
4x4x.1875 front beam?
2x3x.1875 mid/rear beam?
3/8" pin tabs?
1/4" gussets?
1/4" plate to hold the angle, held in by up to 6ea 3/8" bolts?
3x3x.1875 upright for 3-pt and middle support.
blades at 5 degree angle?
blades 15" apart?
blades in front 2/3 of skids?
What do do about the blades where the meet the skids (at an angle). Probably leave them square cut and whatever gap is ok....?

I'm confident it's build-able and would work. But anything to hedge my bets against bending/breaking/etc. is good to do now.


View attachment 382787

For the beam sizes I would beef them up to 4" square tubing .250 wall and make them all the same. If someone needs to buy this it is usually available in 20' lengths, so one stick can build the whole plane. It is desirable to make the whole plane as rigid as possible without the skids being able to flex independently. You want the whole thing to stay as flat as possible so that when one side rides over or through a high spot that the whole weight of the plane is pushing down on it.

If you look at the top frame with the beams figure out the best way to reduce these from twisting. On my plane I have box tube between the beams to make it more rigid. Placing these pieces in line with the lower links also braces the tubing from bending or flexing in a hard pull but that is a secondary benefit.

I built my 8' plane back in 2009 and made it out of materials that I had on hand for the most part. Notice I have the rear beam made from 4x3 rectangular tubing, that works okay and is what I had left over to use. It would be better if it were the same as the front beam which is 4x4 tubing.
Also notice that the skids are rounded on each end,

Brian and I both use our planes in reverse as well as forward travel so you want to limit the effects of the skids digging in. In the last picture notice the skids have more of a ski shape to each end this does help reduce the gouging when the land plane is tilted either direction.