Wall Mounted Rotating Jib Crane

Get an engineer that knows what he's doing, you obviously don't! Depending on the swivel of the beam the hinges go from a straightforward shear to a side shear. The bottom hinge will also go in to compressive stress. Lifting gear is a specialised field, get it wrong and your going to jail for a long time!

The hinges need to take vertical load 600kg. Whether it's shear or compressive depends on which part of the hinge you're looking at. You might be able to share this load between the 2 hinges, but I'd allow some safety in case one gets more than its share. Or design one hinge for 600kg and the other for no load e.g. sliding on a pin.

Also the hinges see horizontal loads 600*3.5/D. When the beam is at 90° to the wall this load is away from the wall for the top one, towards for the bottom. If the beam parallel to the wall, the horizontal loads are also parallel. Assuming 600kg vertical shear, max resultant shear = 600*√(1 + (3.5/D)²). Depending on the design of the hinge, there will also be bending moment in the part of the hinge projecting from the wall.

Cheers.....Codey

''Codemaster''

''Depending on the design of the hinge, there will also be bending moment in the part of the hinge projecting from the wall''

Can you please explain more on this. Do you mean the bracket that is attached to wall should be designed for the bending moment Mb=(600x9.8)x3.5?

Also i cannot imagine how the hinge (plain bolt) will support the vertical load 600x9.8? i think the bracket will have to take care of this vertical load.

Thanks for your inputs

''Depending on the design of the hinge, there will also be bending moment in the part of the hinge projecting from the wall''

Can you please explain more on this. Do you mean the bracket that is attached to wall should be designed for the bending moment Mb=(600x9.8)x3.5?

No, just the maximum force parallel to the wall, estimated in my #2, x the distance from wall face to hinge pin centre.

Also i cannot imagine how the hinge (plain bolt) will support the vertical load 600x9.8? i think the bracket will have to take care of this vertical load.

The vertical load 600kg has to be transmitted to the wall, and can only be via the hinges. The moving part of the hinge rests on the fixed part, total load 600kg. Depending how often you want to swing the jib etc, a thrust washer might be a good idea.

One more thing with respect to your point on designing the hinge to take the full sheer force;

I totally agree with you in case of the 600 kg load is swinging then we may have the upper hinge will take most of this load than the lower one.

There's no reason the upper hinge takes most of the load. If D is distance between the bottom faces of the hinge parts on the jib, and due to construction tolerance (or just a cock-up!) the parts on the wall are closer than D, all the load is on the bottom hinge. If this distance is > D, all the load is on the top. That's why I suggested some safety. This applies for e.g. a simple pin-and-eye type hinge, if it's something different you need to take account of the actual design.

Thanks again ''Codemaster'' for your insight.

One more question to add with reference to your last post; how to choose a suitabe distance D that will make both hinges share the load equally?

Do read earlier posts and have a think for yourself!

If you make the hinge separations on the jib and on the wall as near equal as you can, the load might be roughly shared, but it won't be exact. You could make one hinge adjustable, (e.g. with shims) but you'd still need to use some judgment when adjusting, as you can't measure the load on each. The loads will tend to equalise somewhat over time, as the more heavily loaded one wears faster and transfer load to the other.

It was very kind of Codemaster to give you hints but considering the kind of questions you have written I would STRONGLY suggest to ask a qualified person to make the design, you are not able to do the right job because you do not have the basic knowledge of mechanics. What you do is VERY dangerous for you but can be dangerous as well for other people and you are allowed to play with your life but not with the life of others.

"There's no reason the upper hinge takes most of the load."

Rubbish. Describe your method of spacing the hinge components that OP is using (U-bolts on the wall and the column and a regular bolt down the middle), so that the load will sit equally on them. It will always sit more on one than the other, perhaps all on one and none on the other.

Where's the rubbish? You seem to be repeating what I said, that the load is unlikely to be shared equally between the 2 hinges, and might all go on one or the other (I gave a bit more detail about how it might all be on the top or the bottom hinge).

What I was really querying was the 2^nd paragraph in #4, which I read as saying that if the load were unevenly shared, it would all go on the top hinge, which isn't the case. Reading it again this seems to be the gist of it, but I'm not entirely sure what he's saying, looks like English is not his first language.

TonyS made a good point in #14, need to ensure the wall will take the loads.

Codey

the top hinge will be in tension and the othe in compression. i'm dont think that shear strengh is a critical factor. it's the upper hinge that will carry the largess amount of the load.

As your illustration shows the entire radial and axial load transfered to the 'hinges', then perhaps this Hinge Design Guideline will help. See page four.

As has been said, there are other factors involved. This guide is exactly that: a guide. Please have your figures reviewed.

Very useful for my application. Thanks a lot.

Just an FYI:

Here in America, A lifting device to be used in a production/manufacturing/industrial use for anything other than at home personal use MUST be approved by a licenced Engineer. If you are not a licenced Engineer, and don't have one that has reviewed ALL of your designs/calculations, and this is to be used somewhere other than your barn It will be illegal, and if/when an accident occurs YOU will be 100% liable for all injuries/deaths/property damage occurred by the faulty design. Just want you to be aware...

Even if your boss has asked you to do this, you need to keep your backside safe. At LEAST have an Engineer sign off on your design. It's An Engineers job to ensure it will not fail, and they will assume all liability/responsibility if it does.

Jlstitt, if you want to operate this jib crane by yourself and get killed or maimed in the process due to a catastrophic collapse, then go ahead, and paraphrasing Dirty Harry, "make my day".

But if it involves others that can be adversely affected by a collapse, then you're dead wrong in your statement. Enough said. That's why there are laws on the books to protect people from bad designs made by non-licensed engineers, etc., or have you conveniently forgotten that they exist in every state in the Union, and for that matter in most countries? There was a time once in this country where those laws didn't exist and the common result was that many people died from piss-poor designs that failed where those designs were made by non-qualified engineers and inexperienced engineers, and yes, some non-engineers. You had better read up on your engineering history.

No name calling is tolerated in this Forum. Get it?

i meant no offense, but many of us do-it-yourselvers have to make do with what we can design an build with what we got laying around the shop. when it comes to personal safely, i try to incorporate a safey factor of x5. i should have mentioned that in my comment, but i think that design i suggested is at lesast 5 times stronger than his design. i've been an ironworker and rigger for many year and have found that most people have an instinct for what's safe or not.

jlstitt

There are manufactured jib cranes available all around the world, where the companies that produce them have licensed professional engineers on staff that design and certify them. Many are located here in the USA.

They come either wall mounted or floor mounted....

Do yourself a favor and contact a reputable crane manufacturer instead of designing and constructing yourself on the cheap.

Just out of interest what's this wall made of?

In fact this is not a wall. it is the building column where the crane to be fixed, around 18''x18'' W beam.

What is a W-beam? I'm familiar with most rolled-steel sections, but I don't think I've come across that. Having said that, I'm sure 18" x 18" will be strong enough!

In fact this is not a wall. it is the building column where the crane to be fixed, around 18''x18'' W beam.

In that case, a structural engineer should verify the crane loading will not adversely affect the building's structural integrity.

Think that's going overboard? Try asking the building owner to sign a waiver absolving you of responsibility should the crane damage the column and/or structure.

extend the axis of you hinge pins to a point where you can run a rod from your upper hing to the end of jib arm. a 45 degree angle is norm. in other words, add a hinge above the two hinges shown in your drawing and attach a rod from the upper hinge to the end of the jib arm. the upper hinge should be the same height above the arm as the arm is long. this should give you a 45 degree angle