Superduty dump build

[Iplayfarmer]

... the cosine of 90 is 0. So that completely cancels out the 2ABcosC and thus you are left with just C2=A2+B2

That's the only part I remember from High School Trig. I use it all the time. Now that you've reminded the of the full thing, it might be even more useful.

 

[DumbDozer]

If the bed is 100" long for example, and the cylinder is hooked @ 50", the dump capacity would simply be the SIN of the angle mentioned above x the cylinder force. BUT if the cylinder is mounted farther forward of the rear pivot, like at 60", this increases the capacity by 6/5ths. And if farther back, it reduces capacity.

Egg-zactly, ( if I recall
close enuff for Govm't work,

under any circumstance, looks pretty dang neat to me!

 

[Iplayfarmer]

I finally figured it out!!! The equation to find the torque needed to begin dumping a bed is as follows...

(1/2 the length of the bed) X (weight of the load) = (initial torque needed)

I know this is the same thing that DumbDozer said, but I proved it to myself with multiple calculations, thought experiments, etc.

This equation assumes three things... The truck is level, the hinge is at the very back of the bed, and the load is evenly distributed. Any weight overhanging the back of the bed can be subtracted according to the same equation.

So, In PowerStroke's example with a 6500 pound load and a ten foot bed (ignoring the 6" overhang for now) the torque needed is 1/2 of 10' X 6500 lbs. = 32,500 ft.lbs. of torque. Where the ram is located 9' in front of the hinge, the vertical force needed at that point is 32,500/9 or about 3,611 pounds of vertical force.

To LD1's point, this is only the force in the direction of gravity. A few trigonometry calculations will get you the portion of that force that is tangent to the effective angle created by the hinge being lower than the top of the ram. I think I'm right. Correct me if I'm wrong.

 

[LD1]

That is actually very close to get a rough measurment.

In my previous example, using the 1500PSI numbers, I calculated that the cylinder force was ~10,000lbs and would dump almost 20,000lbs @ bed center.

Using your rough #'s:

A 20,000lb load would require 100,000ft-lbs of torque

100,000/9= ~11,000lbs of force required at the cylinder. Which is close to what I calculated.

This method you describe is good in the "design" stages of the build.

But doesn't help much to calculate the "actual" finished lift and angle specs.

For example, it will tell you how much force you NEED to have, but you still have to do a little trig to find out what the angle of the cylinder needs to be.

But as you have found out, there's more than one way to skin a cat:laughing:

 

[davygp38]

Good post, but what I am interested in doing, is to use a dump body with a gooseneck hitch. Could you post a picture of how you set it up?

 

[Iplayfarmer]

...But doesn't help much to calculate the "actual" finished lift and angle specs.

For example, it will tell you how much force you NEED to have, but you still have to do a little trig to find out what the angle of the cylinder needs to be.

But as you have found out, there's more than one way to skin a cat:laughing:

Understood. Keep in mind I've tackled the problem by calculating the force needed then one can calculate the force available. this series of formulas could even be used to determine the angle that the ram has to be placed at in order to generate enough lift to dump a bed. If someone is using a ram that is just barely big enough, the angle calculation may be very important.

The other thing that has to be considered is that these numbers generate baseline estimates. If a dump bed is loaded front heavy it will take more torque to dump it. If the truck is nose down that can also have an effect.

 

[powerstroke444e]

Did a little more work on the truck and I know the rule on the site is more pictures the better.

I got the tailgate built and built the rear of the bed IE were the tailgate contects. Made a 2way gate and will put a small grain door in it for the pea gravel will be easier to unload in to my small dump trailer that I pull with the atv with out spilling it.

Also built 2 toolboxes on the rear and with the other side boxes I have on top of these will be nice place to keeps chains straps or more junk

I will still have a 6 x 10 bed for material which with pea gravel dirt or sand it will be easy to over load.

 

[powerstroke444e]

Well got it painted today:thumbsup:. Here is a picture. I started wiring it and should have it done within the week.

 

[powerstroke444e]

Finally got it finished and took it out for the 1st time tonight all went well. Got all the lights working and strobes working. I have not had time to weigh it yet but later in the week going to haul a load of scrap so will know then. Yes stuff in tool boxes slide to back.
I put lights in all the boxes on the rear and in bed so I can see @ night they are a big help.

 

[Iplayfarmer]

The lights in the boxes sound like a great idea. The build looks good.