Forklift counter weight taboo calculations

[Milacron]

Originally Posted by 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.

Well, the bottom line is the chances of a critical failure of that nature happening out of all eternity during the 4 minutes I got off to take a photo is so close to zero it's ridiculous. And no "lack of ballast" issues as my pidly 160 lbs that far forward won't make a whit of difference when I'm overcompensating with the extra counterweights anyway.

[dkmc]

Originally Posted by Ox

Boy - that sounds well beyond doo-able, but if you say that you can almost doo it - then....

But if your adding - then it sounds like you actually DOO need to lift, and that truck doesn't sound big enough to me.

It (THEY...there are 2 of 'em identical) is/are outside on 2x6's......like 15 feet from the door. Gravel driveway.....

But then on the other hand (running outta hands here soon) you say that you can almost lift it now. I am really confused? You must be looking to rig this outta the current location - and this is where your issue is?

Didn't say I can almost lift it now, said I can get it airborne and free from it's earthly bounds....by like 6" or more if needed....did that as a test. Need back wheels to stay more-er on ground and lesser in air.

From my experience you should have a min of a 10K for that pic. But if your almost there, keep adding. Fresh tank of fuel. Think heavy thoughts.

Machine manual says 'use minimum 5 TON F/L, min fork length 1.4 meters'....so you score high with your guess

Ox

Originally Posted by starbolin

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.

SO.....lift the machine with the -mast- and -with forks removed-.....?????????
As in 'get a running start & wedge the forklift under the machine' or just what exactly are you talking about???



Perry has the pictures to prove it might work, closest example there is. This F/L is about a 1975 model, pneumatic tires. Pretty well maintained, major rebuild about 10 years ago.

I have a simple frame contraption fitted to the rear now. I also have a 60HP AC motor I will use for weight. it can sit 2 feet behind the counter weight.
I'll take some pics if the situation allows.....

[Ox]

15' from the door x 2 and for some reason your wanting to "sneak" them in?

I don't git it.

Machines moved outside for the dumpster fella and it aint OK for you to take, but you wunna doo it while the nighbor aint there? (Diff neighbor than has the truck I take it?)


You started this by giving us too much info to start with, so your jist gunna hafta finish 'splaining this Lucy.


Maybe the sneak part is the adding weight? Ahhhhh! Now I'm catching on. I may be slow - but I'll git there....


Sounds like a dozen cases of Dew should solve the lions share of your issues. Or maybe something similar?

Machine manual says 'use minimum 5 TON F/L, min fork length 1.4 meters'....so you score high with your guess

Boy - I feel smart now...

I am figuring the load center to be about 37" instead of the trucks 24" standard.

Are you by chance picking this from the rear and the C/L of the machine is at 37"? B/c if it is a mill most all the weight is at the rear - which will make your load center MUCH closer than you may think.





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

Think Snow Eh!
Ox

[machtool]

Originally Posted by dkmc

I also have a 60HP AC motor I will use for weight. it can sit 2 feet behind the counter weight.

Dan.

What do you figure that motor weighs, and what distance would it be, measuring from the centre of the front axle back to where its hanging?

Phil.

[dkmc]

...............

Originally Posted by Ox

15' from the door x 2 and for some reason your wanting to "sneak" them in?

I don't git it.

Machines moved outside for the dumpster fella and it aint OK for you to take, but you wunna doo it while the nighbor aint there? (Diff neighbor than has the truck I take it?)


It IS friday night.....are you hittin the Korn liquor early or what?? *


Machines were delivered to me and I set them outside till I made room inside. If they don't werk, and not werth fixin (lost parameters, other post awhile back) then the will be out fer the dumpster guy.

'Sneak' reference is the added weight/ taxing the mechanicals on neighbors F/L


You started this by giving us too much info to start with, so your jist gunna hafta finish 'splaining this Lucy.


Maybe the sneak part is the adding weight? Ahhhhh! Now I'm catching on. I may be slow - but I'll git there....

Ah!

Sounds like a dozen cases of Dew should solve the lions share of your issues. Or maybe something similar?

see * above....


Boy - I feel smart now...

Well fer a minute there, but now.....I dunno..

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

Think Snow Eh!
Ox

[dkmc]

Originally Posted by machtool

Dan.

What do you figure that motor weighs, and what distance would it be, measuring from the centre of the front axle back to where its hanging?

Phil.

Around 500 lbs.......and (Going off to measure)......

.......motor 'center of mass' as close as 104 inches or as far back as 128 inches from center of front axle, depending on where I put it on the platform.

[paul39]

Originally Posted by dkmc

Around 500 lbs.......and (Going off to measure)......

.......motor 'center of mass' as close as 104 inches or as far back as 128 inches from center of front axle, depending on where I put it on the platform.

Think see-saw.

If you put 500 lbs. 128" behind the front axle, you can lift 500 more pounds 128" in front of the front axle.

Or 1000 more lbs. 64" in front of the front axle.

Or 2000 more lbs. 32" in front of the front axle.

Maybe one of the slide rule jockeys can confirm this.

Or put a 12" rule over a pencil at 6", put a quarter on each end, add a quarter on one side and slide toward center until it balances, add two more quarters and slide toward the center until it balances.

Paul

[KIMFAB]

Why not check with the real forklift experts?
http://onemansblog.com/wp-content/up..._Forklifts.jpg

[dkmc]

Originally Posted by Ox

Are you by chance picking this from the rear and the C/L of the machine is at 37"? B/c if it is a mill most all the weight is at the rear - which will make your load center MUCH closer than you may think.Ox

Nope..side.
There are built in fork channels that run sideways under the machine base casting. Overall width to outside of sheet metal is 75"

[machtool]

Dan.

My back of the envelope calculation shows that 500 lbs at 128” still a little light on. I use the method same as the guy at post #18. Your 7,700lb at 37” centres = 23,740 lb-ft forward moment. You have 16,000 lb-ft built into the truck as it is. (8,000 lb @ 24 inches. So you have a discrepancy of 7,740 lb ft.

Calling 128 inches 10.6 ft you would need 730 pounds at a 10.6 ft lever to gain the missing 7,740 lb - ft.

That’s in theory, I practice, I’d sum the load up with your 500 lb motor, as far back as I could get it (128"). Knowing that’s there’s plenty of safety factor all ready in the 8,000 lb @ 24” fork truck . The machines are on the ground, not coming off a truck, and they only need day light under them.

It will get the machine airborne, but the rear wheels do same when I begin to back up with the load

Sounds like its just about perfectly balanced on the front axle. 500 lbs even if you have it as short as 104 inches should add 4330 lbs on to the steering wheels. That should be plenty for a load that’s just off the ground.

Regards. Phil.

P.S Don’t forget the Pics, but have some one else take them

[swarf_rat]

I was under the impression that forklifts were typically rated with the load at 24" from the leg of the fork (or 0.5m for metrics). This accounts not just for the balance, but stress on forks, mast, rollers, etc. However if you are just concerned about balance (and why would ANYONE worry about the strength of all those other items?) then the real distance of interest is between load and front axle. (Technically speaking for equilibrium we need the sum of the moments about ANY point to be zero, but the front axle is a very convenient point to pick in this case as we can ignore the weight of the forklift itself).

For example, my little Toyota is rated at 5000 lbs at 24 inches out from the fork leg. However the front axle is 18 inches aft of the fork leg, so the overturning moment at rated load about the pivot point is not 10000 ft-lbs (5000 x 2 ft) but rather 17,500 ft-lbs (5000 x 3.5 ft). If I pick the load up at 36 inches instead of 24, the moment is 22,500 ft-lbs, or 5000 ft lbs extra. I can make that up with 1000 lbs at 5 ft aft of the front axle, or 500 lbs 10 ft aft of of the front axle.

In the case of the OP, 8000 lb lift at 24 inches is 16,000 ft-lbs. But the front axle on that lift is likely about 2ft aft of the fork legs, so the real overturning moment is more like 32,000 ft-lbs. Lifting 37" from the fork leg it is 40,700, only a 27% overload (not 44% as stated above). To counterbalance the addtional 8,700 ft-lbs you will need 870 lbs at 10 ft behind the front axle, or 1740 at 5 ft, etc.

[Milacron]

Originally Posted by swarf_rat

I was under the impression that forklifts were typically rated with the load at 24" from the leg of the fork

FWIW, once you get beyond 15,500 lb capacity, it's typical for the rating to be at 36 inch centers. Once beyond about 30,000 lbs, 48 inch centers.

[dkmc]

Ok then, at this point I could use a bit of Corn Liquor to calm myself. No unusual excitement to report, but tedious just the same. Not any extra weight on the rear wheels for sure, but enough to make it steer reliably.
I don't think the hydraulics are very close to their limit.

Here is the apparatus the safety officer would confiscate, and order 'cut up with the blowtorch!' if I had a safety officer...
A test revealed slight additional gusseting was needed between the old cobbled forklift rack guard and the rusty I beam. Jeesh...I don't know where I got the idea that the paint job on this F/L was 'nice'.....it was at one time, but it's a bit war-weary again.




Here is the ballast being precisely positioned (more or less) on the aparatus:



And the full length shot Rube Goldberg wouid draw:

[Perry Harrington]

Nice design. My counterweight has 2 interesting holes for bolting on additional weights.

[dkmc]

The most exciting part was the fact that it had to go in the door from the back, and the damn base being so narrow made it real interesting:





The Z axis motor had 1" of daylight above it and the door.
Cable track got persuaded to skin under....






It has to go into the corner to the right, I'll have to drill the floor & put in a peg to hook the come-along to so it can be pulled over there. It sets on 3 cat-track rollers now.
One down, one more to go......

[Mud]

I'll have to drill the floor & put in a peg to hook the come-along to so it can be pulled over there. It sets on 3 cat-track rollers now.

Yeah, why do those things roll so doggone hard? Even cleaned and oiled they roll hard with weight on them.

That shot with the forks tight together and all the weight above them makes me nervous to look at.

[Milacron]

Looks good DK...I like that better than my chip bin setup. I've got some extra fork carriage back boards lying around...might make up one of those myself. I like the fact that it puts the weight even further back than my bin does.

[.RC.]

For portable counterweights, you could try these, they come in various weights and they have the advantage of being extremely portable and they can even be self moving...

http://img.photobucket.com/albums/v6...terweights.jpg

[Milacron]

Originally Posted by .RC.

For portable counterweights, you could try these, they come in various weights and they have the advantage of being extremely portable and they can even be self moving...

Not really good weight per square foot compared to his motor. I've been in situations where I had a bunch of employees hanging off the back of my forklift...like as many as 6 guys. In at least one situation, everyone of those 6 guys mattered and it worried me the whole time that one would get distracted and just jump off...so I keep saying to them over and over... no one jump off or this $50,000 VMC may go bye bye !! I'd prefer inanimate objects back there for that reason.

[Milacron]

DK, you should have posted WARNING-OX-SHIELD THYNE EYES....now you're got him quivering in a pool of fright just looking at all those "driverless" photos....