[Dave55]

I had a friend that bought one of those dump inserts for a pickup.
Paperwork said it would dump 5000 pounds.
And it would, as long as it was evenly distributed in the insert box or slightly to the rear of the box.
Get it to far forward, not going to dump till you move it back some or shovel some out of the front of the bed.

Who ever wrote the papers for that insert had the math and geometry exactly right with absolutely no margin for error.

 

[Vigo]

Not going to do this without math.

However, I can personally imagine a situation where I both: moved the attachment point of the existing cylinder to a shorter radius from pivot, trading force for travel distance, and then installed a 'helper/starter' cylinder at the front of the bed that pushed vertically until it maxed extension and then the dump bed would just lift off of it. Could be single acting cylinder. Tie that in parallel to the base end of the existing cylinder. Now have a bunch more force in the first 1-3ft of tilt, then hopefully the existing cylinder will be strong enough with its reduced leverage to complete the 'dump'.

That's how my silly brain works.

 

[donmac]

depending where the axle is, would adding a 6" rise trailer hitch give you enough tilt to dump?

 

[JB_4x4]

pictures, pictures, pictures ... just one picture of the bed raised and of the mechanism would be worth more then a 10,000 word description, unless it was inside a CAD file.

I have started to build my own wood processor and dump bed and column load is a thing to consider. Having a side load on a fully extended cylinder is not a good thing, especially a single one. The solution might be to just add another second small cylinder with maybe 7" of travel to further dump the bed. But, as someone posted, make sure you can physically push the bed as high as needed.

Most engineered solutions are going to use mechanical advantage to lift the load and run a fully extended cylinder far under it's loaded capacity and PSI rating, in a straight a push as possible, with a cylinder as short as possible, with the thickest wall cylinder.

 

[Dave55]

Adding a second cylinder to get another 7" of travel is going to get very complicated in a quick hurry.
If you can engineer that setup to do it safely, you might as well build your own trailer, it will be easier.

 

[JB_4x4]

Which is why I have been building my own trailers for the past 10+ years :-D

Though the days of surplus and scrap metal for $0.50 a pound seem to be mostly gone.

 

[Dave55]

That is a large part of why I have so much scrap metal piled up around here. I have no use for it right now, but as soon as I haul it off, it never fails within a week I wish I had it back because a use for what ever I got rid of came up.
Right now I have some 3" x 3" x 1/2" angle that I know has been laying up at the garage for 5 plus years. My son just got a Mahindra 3016 4x4 tractor with a front loader that needs a weight box. That angle is going to make a nice frame for the weight box, and I will probably have provisions to add rippers to the front of the box to soften up the ground so it can dig easier.

Also you are very correct in a side load on a hoist is a very bad thing.
I have watched dump trucks of all sizes flop on their side more times than I care to think about.
It is way easier to do than you think.
Not on absolutely flat ground sideways, don't even think about raising a dump bed.
Cold weather, I watched a 40 dump trailer dumping a load of gravel. Some of the load on one side of the front of the trailer froze to the trailer bed, when the rest of the gravel dumped out and a couple tons was on one side of the bed 40 feet in the air, trailer and truck was on its side a couple seconds later.
50 ton Terex off road dump backed up to close to the edge of the spoils pile, raised the bed and the edge of the pile broke away, truck went over the edge backwards about 200 feet to the bottom of the pile.
Tandem dump truck hauling stumps, tail gate laid down, stump hung on the tail gate chain. Five seconds later the front tires were 16 feet off the ground. At least that one never went over, I was in the drivers seat trying to figure out how to get out of it.
Just like a front end loader with a full bucket raised is dangerous, dump beds with the bed up are also very dangerous.