need cylinder info

[Cidertom]

Building a dump bed for the new(er) truck. Old bed was the standard hoist style. I want to use a front mount cylinder instead of the old hoist to lower the bed height. I thought I knew what I wanted, but after asking two suppliers near by and getting blank looks I thought perhaps I was speaking an unknown language. Can someone translate for me?

What I thought I wanted was a three section telescoping cylinder with a trunnion mount at the head ( next to the rod)of the cylinder. Cylinder would be "upside down" with the rod attached to the truck and the cylinder supported by trunnions at the bed frame. The tail of the cylinder would be in a protected relief. This would enable me to keep the bed low, still get the lift height and capacity. By fastening the trunnions at the frame I won't have to beef up the front of the dump bed to take the load at it's top edge.

Does this make sense and what should I be asking for?

TEW

 

[Wayne County Hose]

This makes perfect sense. That's the way it's done on some dump trailers. As a matter of fact, on the cover of this cylinder catalog, Hercules Sealing Products, the way you describe is the way it's done. Hercules-Bulldog has cylinders and components way cheaper than Northern-Ripoff-Tool.

As far as what you should ask for, either you need to do some engineering or find something similar and copy it. I rebuild cylinders and one thing I can tell you, telescoping cylinders ain't cheap. They are even more to reseal, if you can find a shop to work on them. I do them for garbage trucks and get at least $500 for a simple reseal. Lots of parts and labor. Most are about $800-$1000.

Something way less expensive I've been planning on my dump is two 2 1/2" bore by 42" stroke cylinders mounted on the outside of the frame rails to the dump body. More stable, and way less expensive. Let me know what you come up with.

 

[sandman2234]

I started to go with twin cylinders on my recent ugly dump trailer, but came across a single cylinder with a type of scissor lift. It works great, but I do notice some flexing of the bed that would not be there if I had gone with a pair of cylinders mounted on the sides, or at least a little bit of a distance between them.
David from jax

 

[Cidertom]

I was thinking about the two cylinder method. But... The places I see those is where the load is predictable and even. With the posibility of uneven loading I worry about the bed tweeking. I don't know how much of a problem it could create.

The scissor lift works fine, but the 9" I would need to fit it in is what I want to stay away from. The new truck frame is higher than the old one and I frequently have to use muscle to load. So not having to lift the 9" would be prefered.

 

[sandman2234]

It would seem to me, that if the bed were unevenly loaded, a center single cylinder would allow it to "tweak" more.
David from jax

 

[Cidertom]

Sandman Good point. With the old hoist and the single cylinder I experienced no problems with one side being full and the other empty. I have no experience with the two cylinder method so I have to ask those who have gone before me. From a simplistic physics point of view it would seem that the moment arm of one side to the other would be much greater than the moment arm from mid-line to side. Since the cylinders are in parallel the pressures are equal, not nessasarily the travel.