Building dump trailer

[iowabowhunter]

Hi guys

I started a thread here http://www.tractorbynet.com/forums/build-yourself/241430-manual-hydraulic-pump-dump-trailer.html and was told maybe I should move it to this sub forum. Anyway I've decided to use a 12 volt motor and power steering pump to power a diy dump trailer. What I'm unsure of is the configuration of hooking up the hydraulics. I already have a 3x24 single action cylinder. What I want is a power up / gravity down set up. Initially I was thinking that just powering down the pump would let the bed of the trailer come back down. I've been told I should use a valve to help control how fast the bed comes back down. Soooo can somebody help me better understand this. here is what I visualize. I have a pressure line running from the pump to the cylinder, and a vent line from the vent on the cylinder to the oil tank. I have a valve on the pressure line that also has a hose that runs to the oil tank.The valve works in two ways. In one direction with the pump on it raises the bed. In the other direction it lowers the bed by directing fluid to the oil tank...????? Is this how it will work,,,,or where am I wrong

Thanks
Bob

 

[olde man]

if it is a true single acting cylinder no vent line is needed but if it is like a lot of dump setups a double acting cylinder is used. oil is on both sides of the piston {for reserve capacity} rod end line to tank. sounds like what you have. valve should be a three way pr. in ret. to tank 1 work port only and it goes to cylinder. either incorporated in your valve or in line should be a relief valve they usually incorporated in control valve on most mobile applications.

 

[J_J]

If you wanted to adjust lowering speed, you could install a flow control valve or a needle valve,

Flow valve has adjustable flow in one direction and full flow in the other direction.

Needle valve has adjustable flow in both direction.

Some of the 12v units use a solenoid control for lowering, and others a manual lever.

If that cyl is a DA cyl, he could use the steering pump to raise and lower the cyl.

 

[iowabowhunter]

So I should be able to put a simple flow valve on the pressure line and be able to regulate how fast the trailer falls,,,,,,correct??

HydraStar Flow Control Valve — 1/2in. | Hydraulic Valves | Northern Tool + Equipment

 

[olde man]

yeah he could some lighter trailers use that set up because of a lack of weight, but by and large it's usually power up, gravity down via a three way valve or as you mentioned a solenoid dump valve. even with the da cylinders. you save on some tank space and they actually work smoother than their sa counterparts

 

[iowabowhunter]

yeah he could some lighter trailers use that set up because of a lack of weight, but by and large it's usually power up, gravity down via a three way valve or as you mentioned a solenoid dump valve. even with the da cylinders. you save on some tank space and they actually work smoother than their sa counterparts

So with a da cylinder I would run a line back to the tank from the cylinder?? Would I have to "power down" also or would the cylinder draw the fluid out of the tank when lowering via gravity??

 

[J_J]

Why not steer it up and steer it down.

 

[olde man]

if your going to power down you need a 4-way valve both work ports hooked to the cylinder and the return from the valve to the tank. in the sa scenario is when you attach re port to tank and yes the oil transfers. if you go with power down you probably will want a flow control in the re line to slow the lowering process. or you could simply feather the oil flow with the control valve.

 

[olde man]

since it sounds as if you have a da cylinder used in a sa circuit this is how it should go pump to valve inlet, valve work port to base end of cyl, valve ret port to tank port, and re cyl port to tank port that is in a lower position on the tank. speed is usually controlled by closing your control valve a little. you can use a fc valve but it usually isn't necessary. it sounds like this is what you have. if you want to power down use a four way valve, pump to valve inlet valve work ports to each cyl. port, valve return port to tank port. it sounds as if you already have everything for the sa setup unless you are lowering with anything other than your lever control valve you don't really need the flow control.