need some guidence....

[davedj1]

Looking for thoughts on a hydraulic unit for a dump trailer and crane.
Here is the scenario, I have a crane on my truck with a manual pump jack to raise it, I am going to build a dump trailer (7-10k). I am thinking that instead of mounting the hydraulic unit in the trailer, I would mount it in the truck and use quick connects to hook up the trailer. I have found a hydro unit with 4 circuits, I want to replace the jack on my crane with a cylinder, maybe add one to extend the jib.
If this all seems reasonable...lol
how do I determine what size (bore/stroke) cylinder do I need? will a plow angle or lift cylinder work for the lifting part?
I want to add a cylinder to extend/contract the jib, it will have weight on it when the jib is pointed up so it will have to be fairly strong as well.
I have to get ready for work now but I will try to draw something up later, I already have the crane although it may need some remodeling to accept the up/down cylinder.
Oh, I don't know the lifting capabilities of the crane yet, it's rugged though, 6 ton jack, 3k winch on top. I have lifted about 350-400 lbs with no problems. I am thinking 500 lbs max at half extension.
thanks,
dave

 

[AKKAMAAN]

If this all seems reasonable...

Sounds reasonable

how do I determine what size (bore/stroke) cylinder do I need?

Calculator

will a plow angle or lift cylinder work for the lifting part?

Maybe if it fits....

I want to add a cylinder to extend/contract the jib, it will have weight on it when the jib is pointed up so it will have to be fairly strong as well.

You can not design this extention, with any bending forces on the cylinder. Cylinder have to be relieved from any load, only pull/push forces allowed. That menas you have to design a telescopic arm extention.

Oh, I don't know the lifting capabilities of the crane yet, it's rugged though, 6 ton jack, 3k winch on top. I have lifted about 350-400 lbs with no problems. I am thinking 500 lbs max at half extension.

Make drawing with all measurements

 

[J_J]

To add to what AKKAMAAN said, a cyl pushing straight on will have the highest force in lbs. If you angle the cyl, which you will do in a crane situation, you will have to compute the angle force. As far as cyl stroke and over all length of the cyl will depend on the geometry of the boom and mast and the height the boom will be expected to reach. You can make an extension for the boom by using a tube within a tube, and using a long cyl to extend and retract the smaller part. I would only extend about 2/3 of the boom and keep 1/3 inside the large boom tube. Consider wall thickness on the boom and maybe reinforce the outside of the boom.

 

[davedj1]

thanks so much for the info. There will be no bending force on the telescoping jib cylinder.
I already have the crane built and have used it a few times, It is a sqare tube within a tube, 1/4" wall, 2" OD inside 2 1/4" ID. I am working over an hour and 15 min from home and I'm beat but I will get some pics up of the crane as it is now.
I know that none of you know my capabilities but I have mad fab skills...LOL
I will get some measurements of the crane, I can modify what I need to.

I'm glad to know putting the hydro unit in the truck sounds reasonable.

 

[davedj1]

Here are some pics I just took, I will get measurements soon. This should give you an idea of what I have to work with. yes, there is a bearing on the top, a big carrier bearing. There is also a plate under the bed, bolted through the frame and braced properly.