OT old dump truck mechanism

[gard]

Someone gave me this old trailer made from the front axel of a truck, There is a 1 cu yd dump box on it. There is an old frozen up hydraulic pump but no cylinder. If I can figure out a cylinder I will use the tractor remote to tip it. There is a linkage, pivoted at the back that has what may be cam surfaces and a hole at the top. Attached are a couple of photos with the linkage in the up and down position. The blocks of wood in there are just to hold the linkage up for the photo and a safety in case the come along holding the dump box up fails when I am under it.

Anyone have any idea what the dump mechanism is from? I would love to find an old drawing or photo to give me some idea of what parts I should make.
I think a cylinder with shaft and 4 cam rollers on the end would work. Not so sure about the top of the linkage, perhaps just a long shaft with 2 more rollers. Not obvious from this angle but the linkage is quite a bit narrower than the rails on the bottom of the box. Not sure why they would do that.

There is also the possibility of fitting a more conventional cylinder or winch at the front.

 

[Larry$]

This help?

 

[gard]

Thanks, I could probably make something like that work but pretty sure its not what was on there originally.

 

[Martin W]

Looks like a scissor lift from a grain truck.
Martin

 

[gard]

I think what I have is not the remnant's of a scissor lift but I could be wrong.
On the left side of the base, attached to the trailer frame are 2 ears where a hydraulic cylinder could attach, circled in red.
On the right side of the base is a sloped wear surface with a remnant of grease this extends thru the linkage when the linkage is down, circled in blue.
The linkage, shown in a raised position also has a ramped curved surface circled in yellow.
A roller attached to a hydraulic cylinder can engage both these ramped surfaces when the bed is down then raise the bed when extended.
Or perhaps these ramps serve some other purpose.

 

[Jake M]

I think what I have is not the remnant's of a scissor lift but I could be wrong.

I think you are not wrong. What you have is an old archaic lift mechanism, on a piece of equipment that's been cobbled, =possibly= beyond practical repair. That said, if you're looking for a tractor wagon...... Well, there's that too.....

On the left side of the base, attached to the trailer frame are 2 ears where a hydraulic cylinder could attach, circled in red.
On the right side of the base is a sloped wear surface with a remnant of grease this extends thru the linkage when the linkage is down, circled in blue.
The linkage, shown in a raised position also has a ramped curved surface circled in yellow.

Bingo. I don't now if they were all "identical", but what I've seen remnants of it would have been a hydraulic cylinder that's somewhat oversized from what you'd expect, but with a short stroke (hence the "cutout" in the upper piece, that would clear that in the lowered position. On the rod end there would have been crossways "pin" welded in place, with two rollers on each end, so that they could roll in opposite ways. The outer ones bearing on the upper (moving) part, and the inner ones rolling on the lower, fixed part.The diameter of those four wheels would be a very critical calculation in getting the bed to lift enough but not too much, and they are not the same diameter. (or at least they don't all have to be). The inner ones I'm remembering were a larger diameter than the outers, but I can't tell you why or what size. Maybe functional in the hoisting, or maybe it helped to keep the whole thing "centered" on the ramps? Or maybe both reasons and ten others I don't know about...
That upper part, that could have been attached with another linkage piece, like an "h" link, kind of a smaller version of the moving section you have, OR, it could have been attached at the top by two rollers, each one riding inside of a channel frame under the dump body. Or a thousand other ways probably, everybody made their own hoists back then, they weren't "legos" like they are today). I havn't seen but a few, and NONE in use, even farmers won't fix those. The lifting force is not that great, but the one big drawback is that the bed lift has to be restricted to an "ineffeciently" low angle, because the beds will "flop" back with no real travel limit until something crashes, and then you're hooped, because neither gravity nor a double acting cylinder will pull it back down. Both things get fixed with a modern "lego" scissor hoist.

I suspect that what you have is a partially finished conversion, restoration, or otherwise project that somebody walked away from part way through, and never really finished, just used it as is.. Which means (in my world anyhow), you've got every license to "make it work" I believe from what I've seen, and what your pictures show, that you're on the right track about how it "used to work, but specifics are going to be hard to find, because there were so many variants, in such small, brand specific, "in house" configurations.

 

[gard]

Thanks for that info. It definitely looks like some kind of dump mechanism including frame and dump bed that is attached to part of a truck frame that was bent and welded into a trailer.

The guy who gave it to me used it in the woods a little but found it difficult to back up because of the short nape. He never saw the dump working. Do you have any guess how long ago these were common? I think I can work out cylinder and roller sizes on the bottom, not as clear what should be on the top. No obvious wear surfaces or mounting points. I am not familiar with a h link. From the geometry of the ramps it looks like this could dump the bed at a pretty steep angle but I can see your point about what stops it from going over backwards?
I would have use for a small off road dump trailer around the farm if I can make or find parts. If there is much expense involved, I might be better starting off with a more modern design
The hand pump hydraulic pump that was on it was single acting, I don't know if it will ever work again but I do have a couple of old snowplow pumps and cylinders, might have some used ball bearings...

 

[whitmore]

It definitely looks like some kind of dump mechanism including frame and dump bed ...
The hand pump hydraulic pump that was on it was single acting, I don't know if it will ever work again but I do have a couple of old snowplow pumps and cylinders, might have some used ball bearings...

There's a LOT of hand pump strokes to fill the cylinder that tilts that.
Save your BBs for lighter loads and many revolutions per second; a sleeve/journal
or two will perform well for a lot less agita and money. The friction on the hinge pins isn't
really a significant part of the problem.

 

[Jake M]

Do you have any guess how long ago these were common?

Not really. Like I said, I've not seen them in active use. The one I "maybe" could speculate about would be (useda be before metal went up) on the fence row on the back side of an old hay farm. Right next to the two and a half ton army truck that I scored some obsolete/unobtainable parts from. You can guess what ideas I got right then and there for unloading my army truck, right? That's the fella that told me that the whole design was "weak" in lifting force, and pointed out that they didn't let them tip high due to the risk of a load not sliding out easily. That one was a kinda light duty dump bed on what I believe to be an early 60's International C series pickup. Which puts it in the sixties, if one made some assumptions that may or may not be reasonable assumptions to make about an old farm truck.

not as clear what should be on the top. No obvious wear surfaces or mounting points. I am not familiar with a h link.

The "H" link is a name I'm making up, it's just another "arm" on top of the existing arm, that would allow for solid pins, but take up the relative motion that would be accomodated by rollers if yours were used in "as is" condition. I doubt it's worth buidling in any way if you don't have any infrastructure for that on the bottom of the box, I was thinking more for figuring out what you're working with, maybe there'd be some traces of that. That one was loose on the ground at a old overgrown junk yard that used to sell us demolition derby cars for cheap, so I have absolutely no idea how they hitched that up to make it help and not get in the way.

Being as it's all "custom", and you're starting from scratch, if it were me the first thing I'd do is take those two box frame members closest to the "arm" of your hoist, and "hammer test" 'em. If you can't dent 'em with a hammer, they oughtta take a roller just fine. If you can dent 'em with a hamer, just lay a strip of strapping (flat bar) the width of the tube along it in the area that gets "rolled", to spread out the point contact a little.