3-point jib crane for tractor

[scottybaccus]

As I continue to inch forward on my shop build, I find that I need the capability to lift modest loads (400-600 lbs) to heights of 10+ feet. The first of these chores will be hoisting 10x10 sub-floor frames for the mezzanine up to their beams. The 2x8 framing for a 10x10 section weighs about 400 lbs, and the top of the beams are just over 9 feet. Being so rural, and such a daunting task, you can imagine there is a real shortage of volunteers to do it the hard way...
So, now I'm working just as hard to build a rig to do that job with only one or two guys.
I started with a typical 3-point boom pole that is used on the rear implement linkage of most any Ag tractor.
https://scontent-dft4-2.**.fbcdn.net/v/t1.0-9/24129716_10155307356979538_4607304645809754681_n.jpg?oh=bae7d8a5f785dca46d6aa6b671739a41&oe=5A9FFF57

We bobbed the end off the boom, and installed a standard 2" receiver box into the tube. When used in the intended fashion, I can install a shackle ring draw bar. For the jib crane, we flip the whole thing over, and connect the top link to the mid-point, and add the jib we built, with an electric winch and cable stays.
I still need to add some outrigger feet at the base of the crane to move the load fulcrum back a few feet. This will make better use of the tractor as ballast. I'm also adding a weight rack to the nose of the tractor. We should be good to about 750 lbs, then.
https://scontent-dft4-2.**.fbcdn.net/v/t31.0-8/24130184_10155307357329538_5960686950887238155_o.jpg?oh=a97221c58ddcd15587c9cd6881afb7eb&oe=5A98FF48

 

[VocaTexas]

I built a jib for my skid loader that can lift similar loads to 22 feet. Just be sure you test it very carefully to make sure you don't tip the tractor backwards.

 

[stercorarius]

That's awesome. Great idea.

 

[stercorarius]

Second the weight bar idea.

 

[Richard Cranium]

lots of counter weights.

 

[2oolhound]

When adding the weight bar if it is nice and wide you can guy back to the jib from it. Actually I didn't see the roll bar. I'd guy the top bend of the jib to the roll bar. You could also guy the roll bar to the weight bar in front. Cable is strong on a straight pull but loses 1/2 it's strength at a 45' angle. From the top jib elbow to the roll bar to the weight bar is almost straight so they would take a lot of load.

 

[tarmy]

You may want to do a few calcs on that tip load...by that I mean the tip of the lift point.

That is going to exert a hellava force on that three point...you are probably going to exceed the torque acceptable to the end on the three point set up...

 

[WittHay]

I have seen a similar setup before> But they replaced the upper 3-point link with a long hydraulic cylinder plugged into the tractors remotes. Makes the link solid and the tip of the boom adjustable. Also under the 3-point hitch frame they had big fir blocks as safety

 

[bepjrfan]

That tractor has a 2000 lb lift capacity at the 3pt, you lose about 500lbs of capacity at 24" from the 3 pt, Can't imagine it will support any weight with that large of a boom... With that long of a boom, there is no way you will be able to handle 750 lb's without something failing. That jib needs to have its own ability to support weight and not rely on the tractor to do so...

 

[Farmall 1066]

Why not add an axle and pair of wheels to the bottom of the boom?
You could lift the 3 point to turn, but they'd carry quite a bit of the load.

 

[Dozerhand]

I'm usually a big fan of home made ingenuity but there is nothing about your lifting rig that I like. Way to many things could go wrong. You need a backhoe. I realize that's probably not in the budget but that's the way it is. I too work by myself a lot. Who is going to call the ambulance for you when that rig collapses? Work safe. Get the right tool for the job.

 

[scottybaccus]

That tractor has a 2000 lb lift capacity at the 3pt, you lose about 500lbs of capacity at 24" from the 3 pt, Can't imagine it will support any weight with that large of a boom... With that long of a boom, there is no way you will be able to handle 750 lb's without something failing. That jib needs to have its own ability to support weight and not rely on the tractor to do so...

Fair points, but the 3-point hitch hydraulics were never part of the plan. In it's intended mounting, the hydraulics are fully down, and we are only using the chassis for it's attachment points. Some kind of outriggers to bear the primary load was always part of the plan, but we had to get it erected to see what that would entail. In the end, a wheelie bar fit the bill.
We put two 900# casters on the back, a couple of feet aft of the main boom, shifting the fulcrum to the rear by about 5 feet. When set up, the wheels touchdown and take the load. The tractor is now just ballast.

https://scontent-dft4-2.**.fbcdn.net/v/t1.0-9/24177229_10155320209334538_3499579847453770482_n.jpg?oh=0df27c8363c607861150ad808bdac018&oe=5ACEE520

In fact, it worked so well that there was absolutely no lift on the nose of the tractor at 400#.
I was able to lift both sections of subfloor that I had already framed in just a few minutes, with no assistance.

https://scontent-dft4-2.**.fbcdn.net/v/t1.0-9/24131575_10155319212234538_4670946427115056973_n.jpg?oh=fa6165a1245554fb38bcaef5e4d8d7ef&oe=5A9B13A7


I still plan to add a weight rack to the front, but that is already needed just to tote the mower deck around. I think my goal of 500-750 Lbs capacity will be easily realized. Under the 400 lbs we put on it, today, the cable stays showed no signs that they were being drawn any tighter than our preload, there was no visible sag of the boom, and no lift of the front wheels. We even used the steering axle to guide the load into it's landing position. The tractor is super easy to move by hand, gripping the lugs on the rear tires. We didn't start the engine until moving the unloaded rig away from the work area.

 

[scottybaccus]

I'm usually a big fan of home made ingenuity but there is nothing about your lifting rig that I like. Way to many things could go wrong. You need a backhoe. I realize that's probably not in the budget but that's the way it is. I too work by myself a lot. Who is going to call the ambulance for you when that rig collapses? Work safe. Get the right tool for the job.

I spent many years in a back-hoe seat. That's way more lifting capacity than I need, in a package that won't fit well in my space. I've been "engineering" fabricated metal products for 20 years, and have a good working knowledge of load calculations and materials. While I didn't put a calculator to this one, I did apply some dead reckoning from existing machinery that we've used in the past. For the 500-750 lbs we want this to handle, it's well built, and very suitable. The only draw-back seems to be a fairly high level of effort to set it up. At this point I have two implements, one low capacity, high lift, and another higher capacity, low lift, for under $800. I think the only thing I didn't buy new is the cable stays and the winch. In any case, it did the job, today, in only a few minutes, with no drama or suspense.

 

[scottybaccus]

Why not add an axle and pair of wheels to the bottom of the boom?
You could lift the 3 point to turn, but they'd carry quite a bit of the load.

That's exactly what we came up with. There's no intention to use it for transport, so no need to lift the three point hydraulics. The way it's setup right now, the wheelie bar takes the load, but doesn't allow the front wheels to be unloaded, so steering is still quite easy on a hard surface. If i use it off the concrete, it will be in straight line movements with little maneuvering.

 

[scottybaccus]

I'm not sure you can get enough weight in the front to counter 750lbs on the end of that stick.
Outriggers are fine, but you need a stinger in the rear that wedges to the ground.

Math in my head says you need 4x750 to lift it without a stinger. Lift yes, move... No. When you crush those front tires and try to turn, it's gonna flip.

I'm not sure where anyone gets the idea that we intend to drive around with a load dangling from the boom. It's a crane, not a transport.

Today we raised 400# with no ballast on the nose at all, and never saw any lift on the front wheels. The tractor weighs 2600#, before we put the boom on it. I may put about 250# on a rack out front. That's pretty standard for any attachment I might want to use.

 

[quattro_sinko]

Awesome work. The unit looks great.

 

[creativecars]

Very nice, I may have to do a similar thing.

 

[scottybaccus]

Today, I was able to easily lift 2-3 sheets of 3/4 plywood at a time, up to the mezzanine. It was a piece of cake, even working alone. The boom was about two feet shy of enough clearance to lift the plywood on edge, so I tried raising the hydraulics, lifting the wheelie bar off the ground about 18 inches. Nothing to it. Still no ballast in the front of the tractor, and no indication that it was taxing the hydraulics. It took me no more time to move ten sheets than it would have if I'd had two others helping. I think it's time to paint this thing.