Forklift counter weight taboo calculations

[dkmc]

Plenty of sites discuss de-rating forklift capacities for more distant load centers:

http://www.rightline.com/calculator.html#Capacity

What I need is some idea to calculate how much MORE
weight I need to slap on the rear to keep the wheels on the ground....without overdoing it. Then again, the saftey officer would probably lecture that even 10 pounds more is too much. But I suspect machinist types tend to push the envelope a bit if a decent F/L needs a little help now-n-then...

I'm lifting a VMC, about 7600-7700 lbs, only F/L available is a 8000 pneumatic clark. It will get the machine airborne, but the rear wheels do same when I begin to back up with the load. I am figuring the load center to be about 37" instead of the trucks 24" standard. Don't have to go far, about 25 feet total.
Don't want to add more counter weight than is truly needed....

Any estimators willing to come forward?

[Keelan]

I'll put the popcorn on. This is going to be fun.

[Hdpg]

350 lbs of aluminum perched precariously on the back end of the forklift worked for me under similar circumstances. Not that I am suggesting you should do this.

[jmead]

mmm popcorn.
Seriously, does your bull have the hydraulics to lift it level at that load center to begin with?
My experience with Clarks isn't encouraging.
Aside from that I'd think minimum of 500-? lbs depending on how far back it hangs.

[Stuart Caruk]

Last time I watched this stunt, they flipped the VMC off the front of the forks when the chain holding the counterweight slipped and the forklift slammed down hard. They had several thousand pounds of scrap to use for their next jury rig lift though...

My favorite has to be watching to lift trucks with not enough reach pick up a bridge crane to set it on the rails. They picked up the crane from near each end, set it on a huge semi matching set of pallets, and then proceeded to pick up the pallets and move into position. They stopped short and one forklift tipped forward dropping a brand new gantry from about 18' to the ground.

The crane rental, in retrospect would have been a really good deal.

That said, why not try moveable ballast... look for the fattest guys in the shop that have enough brains not to jump off...

[wippin' boy]

if your that close hog tie a couple 4x4's under the far side and drag it

[peterve]

Originally Posted by jmead

mmm popcorn.
Seriously, does your bull have the hydraulics to lift it level at that load center to begin with?
My experience with Clarks isn't encouraging.
Aside from that I'd think minimum of 500-? lbs depending on how far back it hangs.

IMHO
A greater distance of the same load on the forks does not need more pressure on the hydraulics to lift it

Otherwise you could secure a FT just with a bypass on the hydraulics to make it impossible to get it off the ground

If I can lift a load on 1 mtr from the mast I can also lift it on 5 mtr
If I can keep the FT on the ground
A greater distance creates a greater force on the forks the carriage the rollers and the mast Not on the chain or the hydraulics besides a bit more friction

Peter from holland


Peter from Holland

[Ox]

No - neither of these trucks were mine. The biggest trucks that I have had are 8's. These were 12 and ??? 25K? Both rentals. Neither one blew a hose. Both failures were internal to the tilt cycls. Or possibly the spools? I know the first time they told me it was something in the cyl tho. Not sure the last time? No external oil either time. Oh - BTW - the 12didn't look very old at all. The 30 was an older unit - yes.

Actually the fork truck rental delivery guy was spotting for me on the way in the building too. All of a sudden the load was going down and he knew that Ox didn't just decide to park it there while he was still motioning ahead. He knew something was up.

Danger of human life/limb? I didn't say enything about that. There are plenty of humans to go around. One or two going MIA aint gunna make much diff. If someone is there watching this all go down and decides i'd be a swell time to check out the bottom side of the load, then maybe they desserve what's commin' to them?

I'm talkin' IRON!


Perry, once you got off - you jist lessened your trucks load cap as you jist removed some of the ballast. In the time you got off and wondered over there to take the pic - you could have jist backed up another 2' and been sure of your situation and lowered it. Besides - with an 8' gap between your machine and the trailer - I'm guessing that you should have had a pretty strong sence that you were clear. (I know that your much smarter than that. )


Per Peter - You know - that would make sence, but jist doesn't quite seem to be the case.


And BTW - NO - my fork trucks sleep INSIDE! Although I did have a block heater added to my 8 jist in case it hasta sleep down to the other building in the winter sometime.


---------------------

Think Snow Eh!
Ox

[starbolin]

Originally Posted by dkmc

I'm lifting a VMC, about 7600-7700 lbs, only F/L available is a 8000 pneumatic clark. It will get the machine airborne, but the rear wheels do same when I begin to back up with the load. I am figuring the load center to be about 37" instead of the trucks 24" standard. Don't have to go far, about 25 feet total.

That's more than a little overload. Just multiply the weight by the distance. 8000 lb rating times 2 feet is 16000 lb-ft. That's your rating. Your proposed load is 7700 lb times 3 feet, or 23100 lb-ft. To get the error ratio subtract the two and divide by the rating. (23100-16000)/16000 equals 0.44. Multiply by a hundred to get the percentage. 44% over rating. No wonder your tires are coming off the ground.


A saner approach would be to take the forks off and use the mast to lift one side of the machine at a time onto skates. Then roll the machine to it's new home. That way you are lifting half the weight and at zero overhang.