Poor Man's Forklift

As I may have mentioned I used my boom (cherry picker) to unload my new welder, but I've been thinking. If you could figure out some form of regular set of forks to go on the end of the boom you could leave it shortened and have more lifting capacity because you would not have to reach up over the cargoe you are unloading.

The concept has been nagging in the back of my mind for a couple weeks now, but I just can't seem to come up with and visualize an easy to use and affordable to build mechanism that would allow you to keep the forks level or even close to level when raising and lowering your load.

Not many of us can afford a forklift for that once or twice a year load that could use one, so we wind up borrowing a loading dock down the street, begging a forklift, or improvising. I think it would be the coolest thing if you could come up with a set of 1000-1500lb forks that you could just push your boom upto and slide in a couple pins. Lots of folks have cherry pickers. Something you could build or buy in the $400 - $700 range. Want to get fancy? Put on an air operated hydraulic ram to raise and lower the arm faster.

I was gonna try and invent this gizmo, but the basic mechanics just slip away when I almost have it vizualized each time. I'll let one of you guys invent it and make a million dollars. I'll just buy one when you do.

Bob La Londe

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Reply to
Bob La Londe
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I thought about how ot make one safely and could not come up with anything (not a very high standard). But if you scrounge around you can find a "die lift" or a "big joe" cheap.

I was given this for free once:

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Reply to
Ignoramus31137

Easy. Use a leveling link like used on backhoes an loaders.

Attach your forks with a hinge, then run a link from the hinge to the lifts upright.

A smaller version is used on some windshield wiper arms.

Reply to
Steve W.

It wouldn't work, for a lot of reasons, one of them being that the center of gravity of the load will now be further out from the end of the boom, not closer, and the other being that a cherry picker is designed to handle vertical suspended loads only. You would have to use basic rigging techniques to lift the fork assembly with the proper chains, hooks, etc., which might be more work than it's worth for most loads.

Reply to
ATP*

Someone already did, except it isn't a cherry picker attachment. Check out the Genie Superlift. In my area you can rent one for $35/day.

Grant

Reply to
Grant Erwin

Not quite a forklift, but the carry-all on my tractor acts as a reasonable substitute

Free men own guns - www(dot)geocities(dot)com/CapitolHill/5357/

Reply to
nick hull

The linkage to keep the forks level is a parallelogram. Use the boom for the lower compression element, extend the mast upwards and add a tension link parallel to the boom.

I wouldn't do it, though. Even within its capacity the crane can tip if the load is outside the wheelbase. I've modified the base of my crane a lot to use it on dirt and tow it behind the tractor but left the mast and boom geometry as it was designed. It has tipped over a few times when I was helping someone and they became impatient.

I do my lifting with a platform stacker ($10 at an auction) and chains, web slings and an engine leveler for the shop and truck bed cranes. The chains have a grab hook on one end and an Quicklink eye on the other, plus another grab hook on a shackle that can be placed anywhere on the chain to take up slack. The engine leveler makes a good spreader to keep the crane hook close to the load without having to angle the chains and maybe dent the sides of the welder.

You might be able to add a tie point in your truck bed to winch a load up and down ramps. The first ramps I made were 7' long to lie flat in the bed but now I go with 8' which double as scaffold planks.

The platform stacker makes a nice welding table and work platform for the lawnmower, air compressor, etc. It lifts higher than the hydraulic scissors table that HF sells, which is too low for most truck beds.

I bought one of those HF tables when I was fixing power wheelchairs, and later a crank-up Vestil platform stacker from Northern to work on Segways. Both were reasonable for the price but not nearly as well made as the old industrial equipment I have at home. The biggest difficulty with that stuff was having the leaky hydraulics rebuilt. Luckily there was a man in town who had a hydraulic repair business in his barn and didn't charge me the outrageous prices of the industrial shops. He had the special tool to recut worn needle and check valve seats. I suppose you could do it with a countersink in a milling machine except that the cast bases are very difficult to clamp solidly and squarely.

Reply to
Jim Wilkins

"Bob La Londe" fired this volley in news:g6obm6$b9h$ snipped-for-privacy@registered.motzarella.org:

Bob, just imagine a big question-mark hung upside down. Now, make the bottom of the 'loop' flat, and you have a crane fork. The lift loop is where the 'dot' on the question mark would be. Therefore, the center of lift is directly over the center of the load.

If you need to see a working example, go take a peek at a drywall or shingle-pallet delivery truck. They all have this sort of fork. The forks go under the load; the frame loops up and around to the top-center of the load.

LLoyd

LLoyd

Reply to
Lloyd E. Sponenburgh

innews:g6obm6$b9h$ snipped-for-privacy@registered.motzarella.org:

These things, as Lloyd described them, are commercially known as 'pallet hooks'. As the name says, they are used to lift pallets with a crane. Pallet hooks are a catalogue item, at least here in S-W Ontario.

If you know what you're doing you can fabricate one yourself. Use your best judgement and simply test it with a load 5X as heavy as the intended load rating of the hook. Check for cracks, and if all is OK you're good to go. In my jurisdiction lifting equipment needs to be checked once a year. This probably only applies to commercially utilized equipment.

Wolfgang

Reply to
wfhabicher

I'm not sure I get this. Doesn't the platform on a cherry picker stay level automatically?

Chris

Reply to
Christopher Tidy

and further to that cherry pickers are rated for a one or two man lift . Here in Australia it is illegal to use cherry pickers and backhoes to lift loads other than what they were intended for. If you are caught or someone is injured because of your actions you face heavy fines and imprisonment. Machinery inspectors are like under cover cops here ,you never know when one is likely to show up any where on a job site.

Personally I wouldn't modify or add any attachment to a cherry picker that was not made for it and rated by the original manufacturer. Just not worth the risk in my book.

Reply to
Kevin(Bluey)

A backhoe is probably safer than a cherry picker. You just have to remember not to drop the load by opening the valve all the way. It is not uncommon to see a backhoe with a rated load sticker applied by the manufacturer, so they are not unhappy about them being used for lifting. Usually it's about 1000 kg on a medium to large backhoe loader. There's often not a lot of point, though, when you could just put pallet forks on the front.

Best wishes,

Chris

Reply to
Christopher Tidy

On Jul 30, 6:08=A0pm, snipped-for-privacy@hotmail.com wrote: =2E..

=46rom what I've read, test samples are generally checked at 4X or 5X, then working parts proofed at 2X. I tested my overbuilt, overweight scaffold section to 1000 Lbs vertically and 500 on all diagonals, which the 3/4" EMT braces initially failed.

What is normal practice for testing a single piece without damaging it?

Reply to
Jim Wilkins

This is from memory, but: Industrial material hoists / cranes are designed with a factor of safety (FOS) of 5 on the structure. (Hoisting ropes have a minimum FOS of 6, often more). Companies designing & supplying underhook appliances (lift beams, spreader beams, etc.) often also use this factor of safety, although I have seen FOS as low as 2 or 3 on these appliances.

Engineering designed hoisting equipment is often tested after installation, with a load of 1.25X the load rating to ensure what?? Absence of gross errors, I suppose, and functioning of load brake and overload protective devices.

For the Do-It-Yourselfer the easiest approach is to load test his creation at 5X the rated load. If this is a commercial application then the witnessing of this load test (at 5X rated load) by a P.Eng. would be, in most cases, sufficient for him to sign off on the design. At least I would be prepared to do this provided reasonable workmanship was apparent.

As an aside, people hoists require a factor of safety of 10.

I am not too familiar with (temporary) scaffolding, but I seem to recall that a factor of safety of 2 is required. I forget whether this applies to the tensile strength or the yield strength of the material, but when I design access platforms, walkways, etc. I always base the FOS on the published yield strength of the material.

I use the rules as laid out in the Canadian Handbook of Steel Construction, the Ontario Health and Safety Act, and the Ontario Building Code as applicable.

In case of a scaffold I suppose you could test individual pieces at, say, 3X or 4X the working load, but this is not normal practice. Normal practice is to use the published strength of the material in the design, with the working stresses, at full load, in compliance with the laws and regulations.

Just a word of caution on compression members (posts, bracing, etc.). These are subject to catastrophic buckling failure with very little or no warning of the onset of this mode of failure. The best way for a Do-it-Yourselfer to deal with this is to copy a good existing design. Fortunately the strength of the material affects the buckling failure only minimally, but do not substitute say aluminum for steel when copying the design of a compression member.

Experimental design could be used, also: Make 2 and test load one to destruction. This is sometimes used in the case of pipe fittings or small complex machine components. Also in airplanes :-)).

Wolfgang

Reply to
wfhabicher

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