Powerpack for tipping Trailer

[Rgillard]

Hello,

Was looking up the surplus centre website and seen this 12VDC Powerpack. It says that it will operate a double acting cylinder. I am just wondering does this mean that it has the directional control valves included in it. So if i bought one of the powerpacks and connected it directly to my doulbe acting cylinder could I control its extention and retraction. I want to use it to build a tipping trailer for my ATV and it would leave the hydraulics nice and tidy and it would be electrically controlled rather than having manual valves. Can someone just verify my thoughts or tell me I'm reading it wrong.

http://www.surpluscenter.com/item.asp?UID=2006071307063584&item=9-7187&catname=hydraulic

Regards,
Ronan

 

[jmc]

I'm not familiar with that particuliar model but the ones I've seen that operate a double action cylinder do it simply by reversing the direction of the motor. No external valve required.

 

[HomeBrew2]

That unit looks like it will do what you want and, from the description, works as jmc described, "by reversing the direction of the motor". Note, that my dump trailer uses a single acting cylinder with appropriate pump. Just uses gravity to go down. If you don't need the down pressure, you might find a cheaper unit and use your cylinder as single action.

 

[Rgillard]

I actually have a single acting cylinder quite similar in size to my double acting cylinder. I was not really sure what sort of weight in the trailer body was needed to return the cylinder by gravity. This is because the trailer I am making is quite small in respect to the ones being built by you guys. Will the cylinder return to its retracted position even if the trailer body is light when empty? If so there is no point wasting a double acting cylinder.

Does the pump just pump the oil into the ram directly and there is a pressure relief valve that triggers when it reaches its end point. When dropping the trailer body is there some solenoid valve that opens to let the oil return to the resevoir or how is the cylinder retracted? Can the cylinder be held at say 50% stroke with this set up? Sounds like it is the most simple approach to the build anyway. You guys dont know how lucky you are with that surplus centre. Stuff is so cheap. Is there anyone here from the Uk that knows of a place similar to the surplus centre as to ship something like that powerpack from the states is about $250.

 

[HomeBrew2]

>Will the cylinder return to its retracted position even if the trailer body is light when empty? If so there is no point wasting a double acting cylinder.

I honestly don't know how much weight it takes. Mines dam heavy.

>Does the pump just pump the oil into the ram directly and there is a pressure relief valve that triggers when it reaches its end point.

Yes.

>When dropping the trailer body is there some solenoid valve that opens to let the oil return to the resevoir or how is the cylinder retracted?

Yes.

>Can the cylinder be held at say 50% stroke with this set up?

Yes. And I think the unit said it had double piloted check valves which should hold any position for a year or so.

>You guys dont know how lucky you are with that surplus centre.

Well, I for one, feel lucky and am thankful every day for living in the USA for an awful lot of reasons

 

[jmc]

Here's an address for a supplier in the UK:

http://www.hydraproducts.co.uk/hydraulic-power-packs.htm (I can't post a link ever since they changed this site)

These units can draw some serious amperage, depending on flow rate and required pressure. Are you going to have a separate car battery or try to use the little ATV battery?

Another factor may be when you dump a heavy load, it could lift the back of your ATV when the load shifts behind the axle. Sorry if you've already considered these things.

John

 

[Rgillard]

I plan to use a 12V battery that is separate from the ATV. I don't intend on hauling very heavy dirt around. A lot of this project is for my own learning about hydraulics and it would be so cool to have a tipping trailer. Plan to maybe hook it up on the tractor lawnmower to give more grass capacity. Comtacted that crowd in the UK 182 pounds plus VAT for the double acting pump. Thanks for the help

 

[Soundguy]

If yuo are worried about gravity down.. buy a large spring.. like a trampoline uses.. attach it so that it is in a bit of tension whent he cyl is colapsed.. and in much tension when cyl is extended... the extra 30-40# or pressure needed to overcome the spring will be nothing for those portable hyd power units.. yet when yuo trip the pressure release.. that will be a positive force helping retract the cyl..

Soundguy

 

[PineRidge]

Keep in mind that if your cylinder needs more than .75 gallons of oil to fully extend it then you have a problem. Otherwise the pump looks like it's good to go.

 

[Soundguy]

He can always run it out and add tot he tank to get the lines filled.. then it is just the volume of the cylinder to deal with.. But yes.. if the cylinder volume exceds that.. then you can't extend her any more.. etc. ( better he choses a cyl to fit those specs..etc.... or choses a similar unit with higher specs.. etc.. )

Soundguy

 

[jmc]

Keep in mind that if your cylinder needs more than .75 gallons of oil to fully extend it then you have a problem.

Actually, most of the volume required to fully extend the cylinder comes from the other side of the piston, not from the reservoir. In fact, you wouldn't need much of a reservoir to do this if it weren't for the piston rod. (except for oil cooling)

When a cylinder is fully extended, it holds more oil than when it is fully retracted. The difference in extended volume vs retracted volume is the volume of the piston rod. So the reservoir just stores the extra oil displaced by the piston rod when the cylinder is fully retracted.

John

 

[Soundguy]

This only holds true on DA setups. I've seen plenty of SA setups using these hyd power units.

Soundguy

 

[jmc]

Right. My response was for his application.

John

 

[Rgillard]

Guys,

Thanks for your great advise as usual. I am going to go to a local supplier and see if he can come up with a source or whether he will order it in with another shipment as I cant justify paying 230 dollars on shipping. One Question I have is that on the website http://www.surpluscenter.com/item.asp?UID=2006072507190490&item=9-7187&catname=hydraulic it shows two additional items. Are these two add ons needed to make the powerpack operate the double acting cylinder especially the 12VDC reversing solenoid. Just so I know exactly what I need. I'm sure I could make up a switch instead of the remote control but do I need the valve in order to control a soulbe acting cylinder..

Regards,
Ronan

 

[BBates1962]

Thanks JMP, for giving some incite on the Res, cap, and the cylinder requirements, this has been holding me back and a similar project. Thanks again.

 

[jmc]

this has been holding me back and a similar project.

I hope you independently verify what I said before you invest your money. I'm no expert but just happened to have my own project that required digging into powerpacks a bit. As it turned out, the powerpack's duty cycle killed my application. (Extasy is defined as feeling between the time you invent something and the time you figure out why it won't work.)

John