Help with a trailer unloader idea

[stryped]

TL;DR Summary

Need help designing a way to quickly unload various materials from trailer

I have a trailer that is aproximately 12 feet by 5 feet wide. I would like to design a way to be able to unload 1 to 2 tons of gravel. (This is not a dump bed). I would also like to be able to unload 1 ton of hot asphalt. One idea is to make one of those hand crank unloaders that you can buy for a pickup bed. But the problem is finding a material as wide as my trailer that won't tear and his heat resistant.

 

[anorlunda]

You can buy affordable trailers that tilt to dump like a dump truck. But the cloth based solution may be less expensive. I'll let others suggest which cloth-like material would be best.

 

[stryped]

You can buy affordable trailers that tilt to dump like a dump truck. But the cloth based solution may be less expensive. I'll let others suggest which cloth-like material would be best.

This is the trailer...

 

[DaveE]

Steel is heat resistant and won't tear.
Maybe you could just put a steel plate between your load and the unloader. Maybe also add some sort of insulation like plywood since steel also conducts heat well.

 

[jrmichler]

I would start by lining the bed and sides with UHMW (Ultra High Molecular Weight Polyethylene). UHMW is the best affordable material available for durable low friction low speed abrasive sliding applications. Hot asphalt might be a problem, though.

Take a look at the floor slat system in manure wagons for one way to discharge solid materials.

If you still want a fabric, look at conveyor belts. UHMW and conveyor belts are available from McMaster-Carr (www.mcmaster.com) and other suppliers.

 

[berkeman]

This is the trailer...

The mesh tailgate appears to be for loading and unloading lightweight vehicles like riding lawnmowers. Is it detachable? It doesn't seem consistent with the loads that you are describing...

 

[stryped]

The mesh tailgate appears to be for loading and unloading lightweight vehicles like riding lawnmowers. Is it detachable? It doesn't seem consistent with the loads that you are describing...

Yes it is detachable. I made that and put that on there for bringing my riding lawnmower and things in the trailer. The sides are metal and the floor is treated wood.

 

[stryped]

Steel is heat resistant and won't tear.
Maybe you could just put a steel plate between your load and the unloader. Maybe also add some sort of insulation like plywood since steel also conducts heat well.

I like the steel idea but it needs to be something that can roll up so as to discharge the gravel. I am not wanting to take something how which is on top of if that makes sense. I had actually wondered if thin gauge sheet metal wood roll up into a mandrel like the fabric. Does on one of those pickup truck unloaders? Could I just you sheet metal and use a pipe as a mandrel to wrap it?

 

[ChemAir]

I had actually wondered if thin gauge sheet metal wood roll up into a mandrel like the fabric. Does on one of those pickup truck unloaders? Could I just you sheet metal and use a pipe as a mandrel to wrap it?

Not likely. If you get the metal thin enough you can roll it around the mandrel by hand, it will dent/damage easily, and could tear during unloading. Also, unless it has a ton of spring in it, it will want to stay in the rolled up shape, so extending it each time could be an issue.

Regarding the trailer, it looks to be of fairly low weight carrying capacity. Most dump trailers for hauling gravel have 2-5/16 hitch balls with 7500#+ axles. You may want to see how much yours can actually hold without damage before you modify it too much. It may just be easier to make smaller loads. 4" deep gravel on that trailer will probably make it overloaded.

If you are near or over the max capacity of the trailer and try to use a drag-off type system, be aware that the weight distribution will change as you unload, giving you a very large negative tongue weight, that the tongue may not be able strong enough to handle without bending.

 

[Baluncore]

You might considered a walking floor. Adjacent slats would move in +sine and –sine.
Put down a sheet of sacrificial fabric or used newspaper to move fines.

Also, lower your hitch point on the tractor to move some weight from the trailer rear axle to the front axle, which will also reduce the chance of the tractor doing a back-flip.

 

[anorlunda]

@ChemAir raised the likelihood of overloading. What's to prevent you from doing that? Law enforcement? insurance? AFAIK, trailers do not need annual inspections. Cars with trailers are not required to stop in weigh stations.

 

[DaveC426913]

I would like to design a way to be able to unload 1 to 2 tons of gravel.

I'm a low-tech, guy.
A sheet of canvas laid down with the gravel poured onto it will allow you to simply shovel it out (1-2 tons will go quickly), and when you get down to the last few inches, simply lift the sheet starting at the cab-end of the bed. All the remaining gravel will flow toward the gate, where you can conveniently shovel it off. When you're done, your gravel bucket collapses into a 3 foot ball of canvas. Extremely convenient.

Alternately, I just got one ton of gravel in a bag in my yard. It's 4 feet on a side, cost 20 bucks (sans contents), and collapses into a 3 foot ball. Extremely convenient.The reason I suggest such a low-tech method is because:

I would also like to be able to unload 1 ton of hot asphalt.

Are you sure this will be more convenient than borrowing/renting dedicated equipment to do it?

You may find yourself re-inventing the wheel, figuring out how to keep the hot asphalt from cooling/hardening/destroying your flatbed, etc. (even if you lay down steel, it may transfer plenty of heat in an enclosed space), and then what do you do with the asphalt-covered steel? What other problems will arise that you haven't thought of yet?

 

[jrmichler]

If you line the trailer with UHMW, you may find that there is no need for an unloader. The photo below is a rock sled that I built for distributing rock for improving walleye spawning beds. It holds two full skid steer buckets of rock, and is unloaded by manually pushing the rock out the back while pulling slowly forward.

The sides are 2 X 12's, and at least one rock was too large to fit under the cross bar. The UHMW is so abrasion resistant that it was not damaged by the rocks, even by the largest rock. It is so slippery, especially with some snow on it, that it is almost impossible to stand up in it. It is so tough that we could drag the fully loaded rock sled over boulders, and the UHMW would just flex.

The rock sled in action:

Why was this done? This was a Walleyes For Tomorrow project (http://walleyesfortomorrow.org).

 

[Baluncore]

https://en.wikipedia.org/wiki/Moving_floorhttps://commons.wikimedia.org/wiki/File:Cargo_Floor_moving_floor_schuifvloer_potgrond_transport.jpg

 

[256bits]

A sheet of canvas laid down with the gravel poured onto it will allow you to simply shovel it out (1-2 tons will go quickly), and when you get down to the last few inches, simply lift the sheet starting at the cab-end of the bed. All the remaining gravel will flow toward the gate, where you can conveniently shovel it off. When you're done, your gravel bucket collapses into a 3 foot ball of canvas. Extremely convenient.

Great idea.
For a one time, or two time affair that would be the way to go, rather than spending the time, money, and effort rigging something up that may actually result in more grief that shoveling for 15 minute.

One cubic yard of gravel is about a ton or 2500 pds or so, more depending upon the grade. That should fit in his trailer with room to spare. ChemAir said 4 inches on the bed. One of the bulk bag containers.
Volume of the trailer -12 ft x 5 ft - , level to the top, 2 foot sides, looks to be accepting 4.5 cubic yard - 11000 pounds of gravel, at least more than double what the trailer should carry weight wise. If it breaks in his yard at low speed, not a problem - don't take a full trailer of gravel on the road though.
OP did say he wanted to move only a ton.