Weight at different height forklift

[vadi]

Hello

I would like to know how to calculate the rated capacity of a forklift at different height?
How can weight to be carried change as the height increase...

 

[JHamm]

As the height of the load increases the distance from the center of mass also increases which means that the torque will increase which in turn makes it more likely for the forklift to fall over.

 

[vadi]

JHamm
But how can we calculate the weight to carry at different heights?
Agree that the forklift may tip over if the moment is more than the other side but how we come to a conclusion of carrying x weight at y height?
Is there any formula calculation for that

 

[JHamm]

Yes, find the center of mass of the forklift and the center of mass of the load it is carrying, consider these two as point masses and find the center of mass of the system, if it lies outside of the box made by connecting the wheels with imaginary lines then the object will tip.

 

[vadi]

Yes agreed that will eb to find out the stability of the forklift if the combined mass does not go outside the boundary.
but what about the condition when the load is taken at different heights? how can we calculate the stabiltiy in that case?
so for eg: a 1.5 ton cpapcaity of 6m height cannot carry full load at max height and will cause instabitlity and hence cause tipover. but how do we set the limit to carry 'x' weight at 'y' height

 

[256bits]

Your forlift should have a plate on it that spells it out for you.
If the plate is missing, contact the manufacturer, or look the model up on the internet where they might, should have the information you need.

 

[Vespa71]

What is the safe operating speed of a Ford Mustang? I'd say it depends on the conditions.

If you drive a forklift-truck at 30 degree slopes at 40 km/h, your load shoud be lighter, your turns more gentle, and load elevation shoud be lower, compared to operated in walking speed at a flat concrete floor.

The only limit I've heard of is lifting capacity. 3 tonnes means 3 t, max, when load's center of mass is 80 cm in front of fork frame. Hydraulics, hardware and counterweight are then scaled to handle that lift.

Stability is up to driver. There are too many variables to make sensible maths from it, for me anyway.

 

[G. E. Hunter]

hmmm - i bet there is a formula for that. velocity, distance from center, weight...experience is best.

 

[256bits]

The only limit I've heard of is lifting capacity. 3 tonnes means 3 t, max, when load's center of mass is 80 cm in front of fork frame. Hydraulics, hardware and counterweight are then scaled to handle that lift.

Stability is up to driver. There are too many variables to make sensible maths from it, for me anyway.

Absolutely and entirely not true to any extent.
If you operate your forklift in this manner and an accident does happen, your case of with workman's compensation or any insurance firm will be denied. Your company will be severly audited for unsafe practices and could possibly be liable for a fine for allowing you to operate a forklift recklessly. The reason I say this is for anyone who reads this posting will not get the impression that the guidlines for safe operation of a forklift are just for the desk drawer. It is better to not find out through accident that the load was unstable.

As the lifting height goes up the allowable lifting weight on the forks decreases.
As the centre of mass of the load shifts to the left or the right of centre line of the machine and forks the load decreases and the maximum height decreases.
As the centre of mass of the load shifts farther forward from the centre of mass of the machine the maximum height and lifting capacity also decrease.

i will come back later with somemore forklift info if not is given in the meantime.

 

[256bits]

Here is the standard ANSI / ITSDF B56.1
http://safetytrainingplusllc.com/wp-content/uploads/2010/02/ANSI_B56_1_20051.pdf


And a YouTube stability triangle
http://www.youtube.com/watch?v=7jt_4PAEh5k&NR=1
https://www.youtube.com/watch?v=7jt_4PAEh5k&NR=1


A view of cg effects with an example of a capacity chart beside the seat of the forklift.
http://liftright.net/stability-triangle.htm

Some more - a slide show
http://www.slideshare.net/mshawver/the-basics-forklift-101-final