OK this is for the engineers out there!

[72hiboy4x4]

Due to a narrow driveway and confined workspace, I find the need to build a Jib Boom to replace the cab on my truck.
What I am looking for is opinions on the size of main pole (diameter x wall thickness) and how far to sink it in concrete to withstand the forces involved. Also the hinge pin diameter. I'm thinking a 1" pin will suffice.
The basic is idea is below....


the swing arm will be about 12', and built using a 2"x10"x.025 channel. with the weight of the cab (or an engine block) on the end, I believe a 2000 lb working limit will be good.
any ideas or comments? this will be a permanent fixture.

[19674x4]

my thought would be 2.5 -3 inch diameter with a .625 wall thickness on the main pole, and 2 inch .625 square tubing for the boom end, with a winch and pulley. just my 2 cents

[72hiboy4x4]

I forgot to mention this is a salvage/budget operation. I already have the boom steel I mentioned, and trying to find a .625 wall main pole thats free won't be easy, or real expensive new.
I was thinking (I know- bad idea) that a 6" diam. x 3/8" wall might be big enough.
I'm looking at about 10' clearance on the jib, so that makes the main pole about 12'-14' in length?

[Jake11]

If you bury it in 3' of concrete it should be plenty strong to lift a cab, or
more. If you got a 3'sqr. 3/8" steel plate, and bolted that at the 4 corners
to the slab, if that's what you got, it would hold too. Why not build an
A-frame. You can lift the cab, and roll the frame out under.

[72hiboy4x4]

that option had crossed my mind (short trip) but we are so close to the neighbor on that side, thats its not practical. this will be a little less intrusive (and less steel to buy). And where I am installing it, I can unload a truck and put the load right into the doorway of the garage all in one step.
there is no slab right where I putting this, (yet), so sinking it 3' should be enough,eh? thats in line with my thoughts. just like to get lots of opinions before I go hurting myself (again)

[Jake11]

I think that would do it. Unless you want to dig more.

[mrung0wa]

My only suggestion is:
If I was Building/Fabricating 'BEAST', one thing for sure I would Definitely 'OverEngineer' it! You can never go wrong by strengthening all of the possible 'weak points'. So far it appears that you have a solid plan. Remember 90lbs of concrete is only $3.00 at the most why not throw in a couple extra bags and while your at it throw in a couple bags of Gravel for more agregete .
Best of Luck
Lawrence

[Jake11]

I would too. 3x3x3. But I have a way of overdoing it. That's a lot of
cement to mix. When you get done, it ain't goin nowhere.

[trukcrazy]

I like that design Mike. Let us know how it works out. I was looking at a gantry rig for lifting, but this looks good. Be careful.

[swissranger]

Mike,

For cranes and similar fixtures, there is a safety factor of two or better three times than the working limit necessary. I think you could reduce your working limit to 1000 lb for lifting cabs or FE engines (even included tranny). If you do that way, the force for calculation is between 2000 lb and 3000 lb. If you choose a safety factor of two, you would have to take a tube with 8 inch diameter and 3/8 inch wallthickness as a main pole . If you take a tube with 10 inch diameter and a wallthickness of 3/8 inch, you would have a safety factor of 3.5 times. I would take the 10 inch tube, if you are going with this design of crane. These dimensions are true for a swing arm lenght of 12 feet.
Moreover you will need to weld a 1/2 inch thick steel plate ( approx. 16 inch x 16 inch) as a foot flange with reinforcement ribs on the bottom of the tube. I am designing packaging machines and not buildings, so I am not specialized in calculating concrete stuff. But I assume that the concrete floor needs to have a thickness of at least 8 inch with a good steel reinforcement.
Finally there are a lot of good quality concrete anchors needed to fasten the crane on the floor.
The build of a crane with this type of design is not unproblematic because of the high torque in the foot area.

In your case I would try to find another solution to build your lifting fixture. How about a strong I-shape steel beam fastened at the sidewalls of your shop? In this way you would receive a rail for a hoist. Of course the sidewalls need to be strong enough to fasten the I beam. Maybe you will need to use columns close to the wall to support the I-beam. These columns will have a centrical load and no torque so their dimensions wouldn't be that big.

Roman

[Jake11]

Welcome aboard Swissranger!
Glad we have some people in Switzerland. I hope I spelled that right.
Correct me if not. All input you have to give is welcome.

Keith P

[binder56jd]

check out www.spanco.com they have a pdf with jib crane specs JD

[72hiboy4x4]

If I was Building/Fabricating 'BEAST', one thing for sure I would Definitely 'OverEngineer' it! You can never go wrong by strengthening all of the possible 'weak points'.
Lawrence

I definately like to 'over-build" on something like this. I think another set of eyes is always a good thing to catch what I miss.

That's a lot of
cement to mix.

Good thing I still have my cement mixer! makes life easier!

swissrangerFirst off, let me welcome you to the site! thats the kind of info I was looking for. I will see if I can find a main pole of 8-10" for this. I also like the idea of a footplate set on the concrete. I will see if there is a way I can plate it to the existing wall behind the main pole. Thanks!
I can't put something like this in the garage. cause my ceiling is only 8' tall. not enough headroom. and with this I can load my car trailer directly without moving anything.

lots of great ideas so far guys! thanks! anyone else have an idea?
what about hinge pins? is 1' rod enough? I don't think I can drill bigger holes with a 1/2" drill!

Binder, that site has me thinking all over again. real good detail in one pic of the hinge design I need to build.

[4x4_Welder]

I would also put a 4" tall piece of square tube vertical in the center of the arm, with a rounded top, and a truss rod over it. Use a turnbuckle at one end to adjust over time, or you can use a flat steel strap the same width as the main arm to prevent sagging. If you have the room, a rear stay brace will help the capacity and stability. If you don't have the room, and adjustable counterweight may be an option. An old steel barrel mounted on a platform at the rear of the pole, with a water fill and drain would work nicely. You could balance out up to 440lbs of the lift, and take stress off the base.

[fordman]

i think swissranger said it all for me. i was considering doing a cantalier extension off of my garage but i have dropped that idea.