Hydraulic Cylinder Sizing w/ Levers

[Artisan]

Guys I am making another widget and it uses hydraulics and I need to size some cylinders.
I am going to stick to just one to start with. The force required to lift will be
the greatest when the boom is at a right angle to the ground yes?


also, Is the following correct;

 

[oldnslo]

Yes I believe the load would be 39000 lbs. Now you have to figure out the mounting angle of the cylinder to see how much of the force is used to lift.

 

[J_J]

What is the angle and the pressure.

If the pressure is around 3150 psi and you have a 4 in cyl with 2 in bore, and the angle is about 70 degrees, then the push force would be about 37,197 lbs which would make the lifting force at the boom end about 2861 lbs

Your greatest lifting force will be when the boom is perpendicular to the cyl, as that makes the arm 90 degrees to the cyl, which gives the greatest lifting force.

If the cyl increases in size or the pressure goes up, the lifting force goes goes up.

You might consider a thicker wall boom pole.

I would put a 6 in stanchion in the middle of the boom and add a chain or cable from end to end.

Will this boom be mobile or permanent?

 

[Artisan]

Thank U Oldnslo, am am trying to learn this stuff and I will look into this angle thing.

JJ,

This drawing was for trying to figure things out and not a "To Scale" deal.
As a matter of fact I planned in a 6" pipe on a slewing ring for a riser yesterday.

I have not nailed down the pressure to be used yet BUT, I am kinda hoping
I can do it in a such a manner so that in a pinch, even if a little slow, a
BX25 can push it (like 1800PSI MAX) or a larger 3000 PSI tractor can
push it to. I am considering all 3000PSI cylinders FWIW.

So this drawing is nothing like what I am really doing. I am really trying to figure out
how to do all these calculations so I can try to figure things out w/o having to ask for help,
and as always you J_J are there trying to help and as always I am MUCH appreciative,
THANK you.

J_J can you lead me to some online calculators or websites that explain how to do these
calculations? This device alone has 4 cylinders and I want to try to do the calcs and
figure in some overkill while I am at it but I want to "try" to learn how this stuff is done.

The boom will drop 10 degrees BELOW what is shown in this image when the cylinder
is completely retracted FWIW.

 

[J_J]

Try here for the force and push angle.

Surplus Center

You can't drop the lift arm no lower than the end of the retracted stroke.

If you put the 78 degrees in the push angle block, it will calculate the force at the cyl clevis pins.

The arm would have to drop 78 degrees to achieve full force.

The pivot point is 1 ft from the end so that is 13 ft, now divide the remaining length into the available force.

My math is weak, so I am sure someone will correct me. But anyway, I do trial and error sometimes.





.

 

[glastron23]

here's one calculator for cylinder plus at angles Hydraulic Cylinder Calculator (Angle Calc) check out some of the other stuff in this link..

 

[Artisan]

THANK U J_J and glastron !

I found a couple of graphs HERE that sum up some info kinda neatly.

 

[davedj1]

Artisan, what is it you are trying to lift that weighs 3k? I'm taking all this in as I am in the beginning phase of building a log boom grapple. I have no intentions of trying to lift 3K but I'm guessing 500 lbs or so. I know the guys on here are way more knowledgeable than me so I try and pay attention.
dave

 

[Artisan]

Dave I have no intensions of trying to lift a 3K log. A 2K log "Maybe" but a stretch even that would be.
I want some safety built in too so a lil overkill is good.

I have really put some exhaustive work into designing this, you kinda have to
when your a dummie... HA! Anyways I found a website that gives you the estimated weight of logs, by species, by diameter at BOTH ends and length.

Look for the "Estimated Log Weight Calculator" at the link above.

I think I punched in a Western White Pine x 20' long x 24" at BOTH ends and it was almost 2500 or so.

THAT is kinda the method to my madness.

Wait till you try to figure out a slewing ring! HA! I saw on utube a guy basically stood a
dump truck axle on end and used that to slew with. Works for him but I want mine to look
store bought, an THAT is a hard nut to crack, but were gettin' thar!

Looks like I am going to go w/ a 67,000 pound Tilting Moment ring, a 55KN would do but...

 

[Artisan]

PS, there is a beautiful slewing ring WITH gears and WITH a hydraulic gear motor on EBAY NOW.
It would work well I think down at what your designing for. It is only $250.00 !!!