Mechanical lifting contraptions

[tonyw]

Hello to all, I am new here and have a perhaps unusual question. I have been building a heavy-duty dump wagon to pull behind our Kubota lawn mower. The greatest difficulty so far has been the lifting mechanism for the dumping bed. A previous attempt failed completely (and it was complicated). So, what are your suggestions for a completely mechanical lifting device? No hydraulics, no motors. I am 16 years old, with moderate experience (but not always success) with stick welding, and I have access to my grandpa's wonderful shop, which has lots of tools and nuts and bolts and all that good stuff!

Thanks so much,

Anthony

[Glenn]

Gravity IS THE LAW. Use it to your advantage and it can become your friend. Build the bed so the center of gravity of the load is near or directly over the fulcrum of the dump bed. You only need to overcome the small amount of lift that gets things to tilt and dump. Always raise or remove the tailgate on the trailer before dumping, otherwise the load will jam the tailgate and you will be unloading by hand.

 

Put a post or A frame on the tongue of the trailer. It should be tall enough and substantial enough to hook a block and tackle to the top of the post and to the dump bed. As you pull on the rope the mechanical advantage of the block and tackle will overcome the weight of the load and tilt it into the dump position. The block and tackle is only for lifting and not for slowing the lift down, or stopping it once it hits the critical point. Once you reach the tipping point the bed WILL move quickly so stand clear.

 

Remember that you can easily overload the trailer.  You will need the load just slightly tongue heavy otherwise you may encounter terrain or other issues that would cause the balance of the bed to move to a dump position which could raise the wheels of the tractor off the ground.

It is all about balance.

 

You could design a lift mechanism using a scissors type car jack. Again, stand clear because once the load reaches the critical tipping point, it will move quickly.

 

No matter what you use, remember that these suggestions are for lift and TOTAL DUMP situations. Once the trailer goes into dump mode, be out of harms way.

 

I can not imagine you trying to haul much weight in a trailer being designed to be towed behind a lawn tractor. You may want to post photos and specification on what the trailer is designed to carry or hold. Better information will get you better answers.

Edited March 19, 2015 by Glenn

[JNewman]

How big a wagon?  Simplest (often the best) would be a pocket to insert a long bar which will act as a lever.  Only problem with this is the potential danger of it getting away from you once the load is over center  if your hinge is in the center like a lot of garden trailers are.  A long lever would move very quickly in a situation where the load got away from you.   Keeping the hinge back like a dump truck would avoid this or doing the math and making sure the load is light enough or lever gives you enough mechanical advantage not to get away from you. 

[tonyw]

I must admit, my wagon is rather interesting. First of all, it has a goose neck hitch! I put one on just to see if I could do it and because, well, it would make my trailer unique. It is really unnecessary, but I like it anyway. Second, the hinge is at the back, (like a dump truck) and the way I built the trailer (completely from "scratch") makes it pretty much impossible to put the hinge in the center. The wagon is pretty big. In fact, it has two axles (wheels from a golf cart and from a regular garden trailer) which makes it look hilarious. But I don't care......

[tonyw]

Glenn: the tractor is pretty strong--a diesel Kubota--it pulls a heavy leaf vacuum around all fall, with no trouble

[Glenn]

At this point we need photos. Otherwise any suggestions would be just a guess.

What is the size of the trailer? With the hinge at the rear of the bed, just how did you plan on dumping the load?

Edited March 19, 2015 by Glenn

[tonyw]

Perhaps in an hour or two I can get some pics. (supper first!) the trailer bed is close to 10 ft long--I forget exactly. Since my previous lifting mechanism, which failed, was complicated perhaps I can get a diagram together here soon. I had no plans or anything when I made it--it just sort of came together in my head, I guess. Thanks again for your help and interest.  

[tonyw]

So, here is probably the most interesting and horrible and confusing technical drawing you have ever seen! At the worst, this will provide you with your day's laugh! This is a diagram of my previous lifting mechanism that failed.

First of all, there is the actual dumping bed, outlined in red. Then, underneath it and attached on a hinge in the middle (not shown correctly) is a thick-walled pipe, outlined in blue. Attached to the other end of the pipe, on another hinge, is a base which runs back and forth in a track, outlined in orange (looks like red). Then, attached to the base in the track, is a cable, outlined in green, which is wound up around a crank, outlined in brown. So, if you can visualize everything, when the crank is turned, it winds up the cable, which pulls the end of the pipe in the track forward. Then, the pipe pushes the bed upward, making the whole process work like a hydraulic cylinder.

The reason this didn't work is because the cable wasn't attached well enough to the base that ran in the track. And so under heavy loads, the cable is always under strain, and it was pulling loose from the base. I had welded wire rope clips to the base and then the cable went in the clips, but the strain from a heavy test load was pulling the clips off, despite my welds. Also, the crank was terribly hard to turn with a real load. I'm sure this is probably pretty confusing, but some pictures of the real wagon might help. They're coming soon.

 

 

Edited March 19, 2015 by tonyw
delete extra pics

[tonyw]

here are some pictures of this wagon. this is a close-up of some welds on the goose-neck hitch

this is the wagon with the bed raised. the tubing on the left is just holding it up--it's not part of the lifting system

this is the pipe on the hinge on the bottom of the bed

this is the track the base of the pipe runs in. So, the main pulling cable is attached to the little loop of cable you can barely see inside the track, and then that main pulling cable is wound up around a crank, pulling the pipe forward and making the bed go up.

Then, here is the base itself, also hinged on the pipe. You can kind of see that the cable clip is breaking.

Edited March 19, 2015 by tonyw
pictures and captions

[tonyw]

So, do you think that this complicated cables and pipes and tracks and hinges contraption would work if it was built stronger? I'm not sure myself, kind of doubt it.

[Jim Coke]

Greetings Tony,

I applaud your efforts so far on your trailer build.. Indeed a learning project., I will offer my 2c.  Your fit up to the wood frame from your 5 th wheel design createds a sheer point and the bolts holding the unit to the frame is a weak point.  I suggest forgetting about the dump feature and consintrate on firming up the structure..  It is a big mouse trap please proceed with caution..  Keep arms and body away at all times..  Just an ol boys 2c 

Forge on and make beautiful things

Jim

[matto]

Go to a garden center or hardware store and look at a gorilla cart.  Very simple dumping mechanics. You can always put a pole on front and hook a boat winch to it to. Lift the dump bed.  Works pretty slick.  Then you could use an electric winch insted and run it off the battery of the lawn tractor to.

[tonyw]

You know, Jim, when safety is the issue, sometimes an ol boys 2 cents are worth a million dollars! Yes, I was a little afraid about that spot where the hitch joins the wood, and thought about bracing it more, just haven't done it yet, and now I think I will. I was hoping to haul firewood with this wagon, so it has to be pretty beefy.

Edited March 20, 2015 by tonyw

[swedefiddle]

Good Morning Tony,

You have created a "Widow Maker" or in your case, a "Death Trap".

At the very minimum add 2 stiffners from the front of the frame to the point of where your hitch connects to the hitch. The way you have it, is a major accident waiting to happen. In the world of tractors, you "MUST PULL THE LOAD FROM BELOW AND IN FRONT OF THE CENTER LINE OF THE DIFFERENTIAL"!!! If you are connected to the standard hitch at the rear of the tractor and you have a heavy load or a load shifts, you have the potential of flipping the tractor back onto the trailer, with you in between. Many smart people are no longer with us, because they overlooked this function. You may have a love/desire to have a fifth wheel, but you have NO STRENGTH in your hitch.

You want to make it dump, what I see is the potential of you getting squashed, between the dump and the frame. You will be cut in two, like scissors.

I have seen and I have survived flipping a tractor, It is scarey!!!

Your life is not worth the experiment of designing a scissor lift. Leave the trailer flat until you have saved up enough money to purchase a proper engineered scissor lift.

Neil

 

[tonyw]

Thanks for the tip, matto. I will try looking at some gorilla carts. Never heard of them before.

something else I've thought about is is there anyway I could use springs to counteract the weight of a load, and then I could just tip the bed by hand?

[arftist]

Thanks for the tip, matto. I will try looking at some gorilla carts. Never heard of them before.

something else I've thought about is is there anyway I could use springs to counteract the weight of a load, and then I could just tip the bed by hand?

​You have gotten some good advice here....you really need to listen. You need to step back from your project for a few minutes and try not to see the whole trailer but rather it's parts;

1. The frame. Lets start here. Shorten the frame to just behind the back axle. Mount your hinge there. Move the bed mounted part of the hinge forward. This will greatly reduce the force required to dump. *Important* If you make this modification you must now have a way to pin the bed down.

2. The hitch. Eliminate the gooseneck. It literally is a deadly accident waiting to happen. It is unsafe in too many ways to be fixed and it is useless and counterproductive. Pretty much inviting natural selection to occur. You are a thinker, you just don't have enough experience yet to be able to design structural elements. I highly suggest you turn your investigations toward the study of applied mechanics, physics and mechanical engineering. We don't want to lose you. Especially if you want to carry firewood. If I thought it would just gently fold down upon itself, I wouldn't be saying anything. That thing is going to fail under shock load, and there will be energy released when it fails. The amount of energy in just 1/2 a cord of green firewood moving at 3 mph will astound you. Did you know that steel is highly elastic? Just before the welds snap, the component parts will bend like springs, storing energy like giant capacitors and releasing it as the welds snap. You will be sitting directly in the path of all that, and helpless. Please don't let this happen. 

3. the dumping system. This was covered by Glen, as well as the notion of balancing the load over the pivot point. His description is pretty much the way to go here, with the possible exception of swapping out the block and tackle for a small hand winch such as a boat trailer winch. Even these can be dangerous by the way. My own brother smashed his hand to broken bits when a hand winch failed under too big of a load and the out of control handle failed his hand. He massively overloaded the winch though. Think the winch will be slightly safer than a block and tackle but either way, that is how this situation is usually tackled. 

Good luck and be safe. 

[Frosty]

I have to second Arftist, scrap that design and start over. This one has too many design flaws to fix and they're catastrophic failures on short fuses. I THINK that's a dead horse but let me know if it needs more beating.

The easiest tilt bed ATV trailer I know if uses the axel as the bed pivot. The tongue is basically a straight bar from the hitch to the axle. The trailer frame and bed use the wheels as the hinge so there is NO hinge weak point. As the frame drops to horizontal or haul position it slots over the tow bar and pins providing the hips that prevent it torquing sideways. Well, okay there IS a hinge pin but it's at the end of the tow bar and consists of a single heavy pin at the center of the axle and is only under stress when towing. The bed's weight and any side motions are all riding on the wheels as it dumps so the hinge pin can wobble and not be stressed.

This will cut the weight of the trailer better than in half. Remove the bed hinge as a weak point. Make it EASY to dump and seat to haul. Safer still, the pinch point is under the center of the trailer, a person would have to TRY to get pinched and seeing as the easiest way to dump it is to stand on the rear corner you ain't going to be under a loaded trailer. If you get yourself pinched laying the empty down you need to find safer things to do.

Oh yeah, the unladen balance point is less than 1' forward of the axle to provide adequate tongue weight without squatting the ATV down.

Frosty The Lucky.

[Dogsoldat]

I'll try to grab a few pics tomorrow after work.   I made my little 4x8' utility trailer so it dumps.  In the front is a hook on the upper  edge of the box and a tab on the tongue.  I have an old cheapy bumper jack that fits in and you lift it up til the bumper gets a good bite in the ground and back into it to lift it higher.  Has worked well behind my truck.  Lost count of how many loads of dirt have gone out from under the house.   Have a tab on the tongue that bolt goes thru to keep it together when your just dragging it around.  Have to figure out what 2x4x8' of fist sized rocks and dirt actually weighs one day and figure out how overloaded the poor trailer has been. 

[JNewman]

Forget my lever Idea I thought we were talking ATV/ Lawn tractor sized trailer.

[Glenn]

I prefer the block and tackle or a pulley to a winch (in many cases) as YOU are the controlling factor in the strength department. You can pull no more than your weight, otherwise you feet leave the ground. Mechanical advantage is then used to increase the work ability of the system.

With a winch whether hand powered or electric the system is often stressed at some point. Cables are undersized, mechanisms are built to the minimum standards, etc, etc. I have destroyed several inexpensive come-a-longs at well under their rated load capacity. They were designed to sell and were not designed to do the job.

 

Tonyw

You have gotten some very good advise and some good warnings. At this point I would remove critical components of the trailer so no one could accidentally use it, and to remove any temptation for you to use it.

IForgeIron is all about safety first. If a job can not be done safely then do not do it. Step back and figure out another way.

 

Edited March 20, 2015 by Glenn

[notownkid]

For ideas Look at DR Equip sight under Versa Trailers.  ONe has a boat trailer hand crank winch used must be 100's of those around on old trailers.  Also uses a loading arm which you might copy.  Just a thought

[tonyw]

I am astounded. Scared stiff. I had no idea I could make something this dangerous! And I didn't even try to! *sigh* AND ALL THAT HARD WORK--GONE FOR NOTHING! Well, on the positive side, it is a 100% learning opportunity. I thank you gentlemen for your suggestions and concern for my safety. I am taking a technical drawing course in school, so perhaps I should sit down and properly plan out this project. And any more design suggestions are more than welcome! keep them coming!

Thanks a million,

Tony

[Frosty]

One last little mistake to remark about there Tony, none of this went for nothing. I used to have all my "designs" saved in notebooks. You just never know when something that's a terrible idea for task A will work treat for task W or I was getting too confident in my ability to outsmart the laws of physics. Information is information and believe it or not some of the most valuable are the "don't do it THAT way!!!" ones.

You also got practice cutting, welding, bolting, etc.ing etc.ing. It's all good, skills you'll use your whole life.

Mechanical drawing is a very valuable craft, not only can you make a living at it but with a little experience doing things you'll be able to make most of the build mistakes on paper first. I'm never without a tablet of graph paper to brainstorm ideas on. It's also good for transferring drawings from the CAD to the workbench or sitting at a coffee shop table making a potential customer's ideas into something that'll work.

Frosty The Lucky.

 

[tonyw]

Yeah, you're right Frosty. Thanks for the encouragement!

[Jim Coke]

Greetings Tony,

Don't feel bad at a little trial and error.. When I was about your age ( years ago).. I got the bright idea to build a sail for my bicycle..  Worked quite well and very fast.. Until I had to try to stop.. Seems bicycle brakes are not quite up to the task and I ended up in a ditch with many bruises and scrapes .. It took Henry Ford few wacks before he came up with s product.. Oh and he was a Blacksmith too.

I wish you well and forge on and make beautiful things

Jim