Dump Cylinder sizing

[Steve_Miller]

I'm in the process of building a dump trailer and I'm not convinced a three inch cylinder will dump what I have built. Is there a calculation that I can use to figure out the starting force I will need at the bottom end? If so, I can post a few dimensions and pictures to help figure it out. Any help would be appreciated. The cylinder I want to use is 3" dia by 30" stroke (gives me approx 55-60 degree dump angle), the bed is 61" wide by 102" long, the hinge is centered 10.5" from the back, the pivot for the cylinder is 53" from the dump end of the box and 9" vertically lower than the box frame. Did I miss anything? My tractor produces about 2500psi, so that equates to about 8 1/2 tons of force on a 3" cylinder


Thanks a million
Steve

 

[J_J]

I think so. A 3 in cyl with 1.5 in shaft, at 2500 psi will have a push force of 17,671 lbs

At 45 degrees, the push force is still about 12,496 lbs

 

[Steve_Miller]

Thanks J_J, the starting angle will be about 10 degrees, what force would that equate to? Do you think it will push up a two ton load?

Steve

 

[J_J]

You will have about 3,069 lbs. of push force You could go up to a 4 in cyl, and at 10 degrees, will have about 5,455 lbs of push force.

 

[Steve_Miller]

J_j, is there a chart or calculation that would tell me what force is available at certain angles? I could lower the cylinder pivot to get a better angle?

Thanks Again
Steve

 

[AKKAMAAN]

Is it possible to use a trunnion mount cylinder, to get a more advantageous initial lift angle.... a 30" stroke cylinder is taking 36"-38" of space...personally I would go with a trunnion mount teleskopic cylinder.....long stroke, short retracted....but I assume that wont fit in the budget.....LOL...

 

[J_J]

Yes, Surplus Hydraulics, select Hydraulics, and on the left, select tech help, and then go to calculators , select force and speed., and enter the numbers.

https://www.surpluscenter.com/hydraulic.asp?catname=hydraulic

 

[Steve_Miller]

Is it possible to use a trunnion mount cylinder, to get a more advantageous initial lift angle.... a 30" stroke cylinder is taking 36"-38" of space...personally I would go with a trunnion mount teleskopic cylinder.....long stroke, short retracted....but I assume that wont fit in the budget.....LOL...

I looked those and yes they are $$$

Steve

 

[Steve_Miller]

Yes, Surplus Hydraulics, select Hydraulics, and on the left, select tech help, and then go to calculators , select force and speed., and enter the numbers.

https://www.surpluscenter.com/hydraulic.asp?catname=hydraulic

Thats what I was looking for, thanks again J_J

Steve

 

[sandman2234]

I saw a dump trailer at a local trailer store today, that somebody had overloaded, and tried to dump. The twin cylinders appeared to have moved something, but it wasn't the load. Instead of lifting the load, they just pushed the frame away from the load. So if your going to increase the lift strenght, make sure the frame will handle what they cylinders are putting out.
David from jax

 

[kennyd]

Baum has some great calculators as well: Baum Hydraulics Corp :: Spec Calculator

 

[Iplayfarmer]

I saw a dump trailer at a local trailer store today, that somebody had overloaded, and tried to dump. The twin cylinders appeared to have moved something, but it wasn't the load. Instead of lifting the load, they just pushed the frame away from the load. So if your going to increase the lift strenght, make sure the frame will handle what they cylinders are putting out.
David from jax

A few principles of trigonometry and a scientific calculator can be very helpful in determining the forces on the dump bed and on the frame.

If you define your ram angle as the angle FROM VERTICAL then Cos X ram force = the amount of vertical force your ram will exert. Sin X ram force = the amount of horizontal force acting on your frame.

Your 10 degree angle in this case would be 80 degrees FROM VERTICAL. Your 3 inch cylinder with a surface area of pi times 1/2 the diameter squared (7.07 square inches) times the pressure (2500 psi) has an absolute force of 17,671 as JJ suggested. The cosine of 80 degrees is roughly 0.174. 17,671 X 0.174 = 3,068.5. To no ones surprise JJ is correct.

Sine of 80 degrees is 0.985. The horizontal force of the ram pushing on your frame is 17,671 X 0.985 = 17,402 lbs. Build your frame accordingly. If you go to a 4" ram the horizontal force is roughly 31,000 lbs. That's 15 1/2 tons.