Dump trailer project

[sotc]

So I got this thing home and starting to work on it. Found some 7k# axles that need to be 3.75 inches longer, working on that now. Also trying to figure out what size cylinder I need. I have a 6 qt., 3000# pump. The dump angle I show here is a 4' cylinder with 30" of throw which will max out my hyd. capacity with a 4" diameter cyl. With a 3.5" cylinder I could go 36" throw which would be better but I don't know if the power ratio is right. I'm hoping some of you can help me figure that out. I beleive 34 degrees will do it but more would be better. I have 66" from pivot point to bed pin and 112 to frame pin. Any help would be appreciated. Black rope shows where cylinder would be

 

[lumberjack]

It looks like your cylinder will be quite nearly flat when the bed is lowered at those current mounts. That'll make it super hard for the cylinder to get the bed raised the first bit.

34* is marginal, dumping up hill will be tougher, especially if you have a good bit of tounge weight (trailer is nose down).

If you use double acting cylinders, there's no reason you couldn't run dual 4"x36"x2" cylinders, the difference would be about 4 quarts, leaving you 2 quarts in the resevoir at full extention.

My trailer uses 2 3.5"x36" cylinders, fwiw.

If you run a single cylinder, you'll need to make the cross members pretty beefy, the first little bit is going to try to shove the bottom cross member mainly forward, the top cross member backwards. If it were me I'd either go with a scissor lift, or twin cylinders mounted by the frame rail (if it were me I'd might go for telescoping cylinders).

A pair of these would be tits, but you'd need at least 10 quarts.

 

[Al Smith]

If you look around enough you could likely find a large cylinder from a dump truck which uses a pitman arm type thing that puts the cylinder horizontal to the bed . --And I might add at a price which would be far less that either using a telescopic cylinder or a set of dual cylinders . If the dang things will lift 12 tons of stone they certainly will lift a trailer full of wood or chips,whatever . If the distance was not so far I have several in my shop but the price for shipping would break the bank .

 

[sotc]

Nice thought Al but again, only 6qt capacity.
Carl, double acting, you mean where it powers down? Thats a good thought, my pump is set up for gravity down but I will look at the schematics and see If thats doable.

 

[stehansen]

Mine has a scissors, and dumps 45 degrees, which will make almost everything slide out even sticky dirt. The frame is looking good.

 

[Al Smith]

It's simple .The way a dump truck cylinder works is you use the non powered side of the cylinder as a reservoir or storage tank for the hydraulic oil . It will hold just enough fluid to raise the cylinder to max .You don't even need a tank .Once the fluid is exhausted the cylinder is fully extended .

 

[lumberjack]

Yeah, Willie.

How is a dump truck cylinder so different than every other cylinder?

 

[sotc]

They telescope

 

[lumberjack]

Nearly all telescoping cylinders are single acting by design. They don't have a built in reservoir like a regular cylinder.

 

[sotc]

Thatswhat I thouht but I have never torn into one. Every one i've seen gravities down

 

[Al Smith]

The kind I'm talking about is just a single acting cylinder that uses a scissor action gizmo .The secondary or non power side is hollow but does not get pressure applied to it . That portion is only for the storage of oil .

Sounds goofy but the oil just goes from storage side to pressure side via the pump or gravity if it is down .Some use a little tank and some do not .

I'm not talking about a big giant 5 axle dumper with an 18 foot bed that carries 28 ton of stone just a little single axle with an 8 foot bed on an F-600 or something .7-10 ton maybe .

I'll take a picture of one the next time I go to my shop plus I think there are a couple of lift assemblies from old chip boxes in that pile of junk too someplace .

 

[Al Smith]

I found a couple on the net,good old Google . Note the line on each side of the cylinder .

 

[sotc]

That 2nd set up looks interesting but both would require a fair bit of changes. On another note, it's axled! I can drag it down the road behind my truck if need be from today on!

 

[stehansen]

Here is my hoist. It will dump about 9500 lbs.

 

[sotc]

You battery and pump are under the bed? I'm tring to figure out where to mount mine right now but it won't be there!

 

[squisher]

Yah that seems a bit odd Steve. If the battery dies can you still lift the dump bed manually?

 

[stehansen]

You can hook jumper cables up to it. If you don't have it difficult to access your battery will get stolen all the time. Once I ended up with a dead battery and the lift was down and I put the battery charger on it. I think I could lift it up with my tractor loader if I had to also. I have a wire that charges the trailer dump battery from the vehicle when your driving.

 

[sotc]

I think i'm going to make a chain box on the tounge and put the pump/battery in there. How is the charge wire hooked up? isn't there something that has to go inline to keep from frying that wire when dumping?

 

[squisher]

I don't know how but mine must charge somehow or other.

Mine is in a box at the front where the frame v's together for the bumper hitch, it has a little clasp on it for locking but I've never had a lock on it.

 

[stehansen]

I think i'm going to make a chain box on the tounge and put the pump/battery in there. How is the charge wire hooked up? isn't there something that has to go inline to keep from frying that wire when dumping?

I put a breaker on it. I figured if it drew too much juice it would trip then reset without me having to do anything (which I'm pretty good at).

 

[sotc]

Well thats a slick idea, what size?

 

[stehansen]

I couldnl't tell you exactly, 15 or 20 amp.

 

[DTW902]

Somthing like this Willie, a battery isolater. Your local auto parts should have them or a RV parts place. http://www.powerstream.com/battery-isolator.htm

 

[stehansen]

That will work just fine. Those are made for RV's so when you are running the heater all night you won't wake up to dead batteries all around.

 

[sotc]

looks like the proper unit