Lift chart?

Could you please be a little less specific?

I am building a hydraulic lift trailer that needs to lift a bobcat at 8000 lbs.

This is the basic design with the hydraulic ram in the front of the trailer. lifting the center of the trailer at a 45 degree angle

Thats a little more specific, but what would be required is cylinder bore if you are only concerned about lift and bore x rod diameter if you are concerned about both directions. Also need to have a better idea of the linkage geometry.

Tim

What does this mean? "lifting the center of the trailer at a 45 degree angle"

The center of the trailer is hinged?

Or, do you mean tilt the trailer to 45°? Can't imagine why.

And, any linkage will change everything.

More details please.

Lyn,

I also don't quite get the idea right now but surely if there is a cylinder being connected, then surely it is not just lifting straight up and down, hence some sort of linkage at work here.

It would be necessary to see at least a sketch of this plan I would think?

Tim

madcity

The easyest thing to do is use ramps I never seen a dump trailer dumping a bob cat they are always unloaded with a ramp either a fold down or portable

I am trying to figure out why the trailer in the picture only is rated at 7000 lbs. Is it a weakness in the design of the trailer or in the hydraulics. This trailer slides on rollers at a 45 degree angle and drops to the ground for level loading from the ground with no ramps. The unit is a M 301 Dyna jack made by Monarch and I will have to get the rod and cylinder size with more photos

Madcity,

It seems to me that you need to explore a few sites like the below link first, then you may have a little better understanding of the fundamentals. This will help you present a more defined question that can be better answered. From reviewing what has been posted already, it seems that you believe that you can raise the capacity of this trailer by only increasing the hydraulic capacity, is this an accurate assumption on my part? If this is accurate, have you contacted Monarch to find the maximum load carrying capacity of the trailer? Is the only weak point the actual cylinder and pump, is the cylinder mounting and supporting members also underrated for the added weight?

http://www.peninsularcylinders.com/CFG/HH_LH_NFPA_Cylinders/HH_LH_NFPA_Bore%20Size.htm

Tim

That is the charts I was looking for!!!! By calculating the rod size and bore size I can figure out what the cylinder will lift and then I will know what is limiting the trailer load cap. This trailer is built hell for stout and I can't see the limit they put on it. Now all I need is the Max and safe line pressure that the M-301 will produce! Thanks Tim!!!

The load will also change due to the angle of the lift in relation to gravity. Any ideas on the effect of the load in this configuration? At full pull stroke trailer is even as shown

Ok, I have admittedly had a few drinks already today. Possibly this is why I cant seem to grasp the sketch?

You show two of something that are pivoting, what are these? The CL of the cylinder seems to be just under the pivot point, how does this connect?

To give any sort of assumption, we need lengths and dimensions.

Tim

Take a look at the photo. You will notice two 45° "ramps" on each side. So, the bed rides on rollers and is pulled forward? and up by the hydraulics (this could be a simple electric winch)with the rollers riding inside the [ shaped channel on each end.

The bed is two sections and the inner section remains horizontal as it rises.

The drawing leaves the bed/beds off.

Is this close???

Yes I see it now that you mention it and I have zoomed the photo. Well I suppose it is a pretty neat concept if your assumptions are correct and I believe they are.

So Madcity, you mentioned prior that your only questions now are the hydraulic hose/piping limitations?

I have checked to see that this system is a very basic DC motor driven self contained pump package, are you still going to use this power package? If so then you will need to increase the lift capacity by increasing the area (size) of the cylinder while keeping the same system design pressure, so your existing hydraulic circuitry will be fine.

You will need to pay very close attention to the power package reservoir capacity as it may not be sufficient as is, this can be corrected however.

The 45 seems to me to be a bit steep, I think I would feel better with a little lighter angle (but thats just my opinion). What do you have for rollers, are they real deal industrial cam followers or good sized roller bearings or what?

Tim

Hi Guys the rod is 1 3/8 and the cylinder is 3 1/4 so we are at 6811 at 1000 psi. That is if the pump can produce that line presure. The trailer is rated at 7000 so how much does the angle of the lift increase the lifting capacity? You can see the rollers in the photo. Tim did you also find out what the max line presure of this pump is?

No I do not know what the pressure relief valve is set at, why not put a gauge on the system and then we all know for sure.

Do your hoses, fittings, lines have any identifying marks?

This is not my trailer and I can't take that liberty with it. But the owner might be willing to sell which totally shocked me. I was planning on building it but now I might be able to buy it and modify it.

So how much pressure can this pump produce and is the line relief all that stops the pressure from building up to much?

Madcity,

Not sure why, but I deleted the information I had downloaded yesterday already. But listen I found this by Goggling the information you had provided yesterday.

Enter the following: Dyna-Jack M301 and see what you get. You will want all this if you intend to buy or build the trailer. If memory serves, it is actually a Bucher Hydraulics package. What is necessary is to search for this information, I am sure that the pump package manufacturer can tell us exactly what the pump is capable of and also what the relief valve is set at.

I´m not doing much today and could do this for you, but wouldn't it be better to get this yourself? Then it wont be second hand information :-)

Before I found this site I spent about 2 days searching the web to find the specs on this pump and trying to find that cylinder chart. I had no luck and Bucher doesn't have all the specs I needed online that I found. Wording of the search perfectly helps and I wasn't sure of the wording for the chart but I was surprised that there wasn't more spec on hydraulic units and the basic calculations needed to find the right pump and cylinder. I am guessing that's what college is for with calculations for basic theory:)

Hummm well we will need to wait and see what Lyn or some other member can do at this point then. But I am not sure if a lifetime of college can qualify anyone to guess what a particular pump package was built with or what its relief valve is set at??? Me personally have no college to speak of, just a low life Technical Coordinator :-)

Now if you really want to know, you visit the below link and find that the Dyna-Jack M-301 type UP pump is rated for intermittent pressure to 230 bar. Other particulars are also noted, an easy way for you to identify just what model you have is by fluid capacity, voltage. Its either a UP-50 or a UP-100 I'm sure.

http://www.bucherhydraulics.com/31237/Mobile-and-Industrial-hydraulics/Products/Power-units/Hydraulic-power-packs,-series-UP/index.aspx?addhilite=M&addhilite=301

In todays information age, all the information for most anything you can imagine is there for the taking my friend.

I hope this helps

Tim

Both of those pumps have twice the pressure needed to run any cylinder size. It seems they designed these pumps for any application. Quite a bit of that info was in greek...:}

If you don't learn something new every day your probably dead

Low Life...I doubt it...:) Thanks Tim

Here is a pic of the rod connection

Seems to me that a winch and some cables would be simpler than a pump, plumbing and slave cylinder.

I suppose if he is going to build one from scratch it would be much easier. Just multi-part the cable until he gets the required capacity.

Could always use the winch to drag the Bobcat or other machine onto the trailer after a hard day and its broken down as well....

You are probably right in this application but if I don't have to build this trailer I am going to build a dump trailer. I have already bought everything to build a trailer except the steel and hydraulics. On E-Bay the hydraulics are very reasonable and the steel is three miles away.