Forklift weight scale/pressure gauge?

Ignoramus8802 wrote:

Sure, most lift companies sell them. They are a calibrated gauge that
attaches to the lift side of the ram. You pick the item up. Release the
handle and the gauge reads out the weight in pounds/kilos. The
mechanical ones work OK but they are hard to read sometimes.
I like the electronic versions.

Electronic versions with a pressure transducer.
http://www.americanforkliftscales.com /
http://www.materialshandlingequipment.com.au/weight-guage /
http://www.forkliftscales.us /

--
Steve W.

Yea but you can't afford it.  But maybe surplus...

During the Viet Nam war, I worked with a super guy that was on a
contract.  He was a lofty Physicist and had gotten the contract to
build a force gauge that would measure the real tension on the bottom
hook on a helicopter.

Cannons and pallets of sheet metal were being lifted all of the time
and from time to time, a copter would drop under the load.

It wasn't a simple push/pull issue - twisting and rocking caused such
effects that they were seen as much of the problem.

Strain gauges were used in a multi-axis link measuring the load.
It was for the most part 4 axis - x,y.z,Theta.  Rocking was a combination.

The unit, a digital scale is used to measure what truck tires press down
= and like tasks.

Force cell or the like.

How would you add it ?  complex.

One might have something on the forks - pressing backwards or bending.
But the cylinder is the best spot - maybe a cell with two eyes - one for
each end and inserts between the cylinder.

See if the forklift company has one on their website.

Martin

On 11/3/2011 9:04 PM, Ignoramus8802 wrote:

On Thu, 03 Nov 2011 21:04:56 -0500, the renowned Ignoramus8802


There may be others.



Best regards,
Spehro Pefhany
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    There are liquid-filled (often glycerine) hydraulic pressure
gauges.  You would need to know the diameter of the piston to calculate
the load from that, and of course subtract the empty load pressure from
the pressure with an actual load in place.

    I think that the gauges go at least to 10,000 PSI.

    Here is one (3,000 PSI) on eBay for only $9.95: # 250921080861

    Here is a 10,000 PSI one: # 250796780436

    Don't worry about the air bubbles in there.  That is needed to
allow expansion when under pressure.  (The bubble should get smaller as
the needle goes upscale.)

    This one is a different design, and goes to 3,000 PSI: 280595831572

    Do a search on:

        Hydraulic pressure gauge

and there are a little over two pages of them.

    Or -- if you want to buy *new* -- check out Enerpac as a good
maker.

    I would suggest starting with the piston diameter, and
calculating the likely pressure range (multiply by two if the piston
pushes a roller chain gear up) before ordering a gauge.  I suspect that
the lift does (or certainly *should*) not go to 10,000 PSI for example.

    Good Luck,
        DoN.

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Don. thanks. I believe that I do not need to do any calculations. If I
assume that P = A + B * W, then all I need to know to find A and B is
the pressure with nothing on the forks, and the pressure with, say, 2
tons on the forks. Once I know A and B, I can make a little table on a
card and put it next to the gauge.

For hydraulics, I would rather buy something new at McMaster for $40,
than something unknown on ebay for $9.95 plus $8 shipping.

Thanks, though, for confirming that it is doable.

i

I added such a gauge to my homebrew front end loader, to set the overload
pressure relief which is somewhat temperature (viscosity) sensitive. The
glycerine dampens vibrations from the hydraulic pump so the needle isn't a
blur. If you mount the gauge in a panel or box it will be better protected
from damage and you can mark the load weights around the dial and quickly
see if the needle is nearing the max.

The gauge cost about $20 in a local hydraulic parts store.

jsw

    [ ... ]


    [ ... ]


    Yes -- that would work -- except that I was suggesting a way to
predict the top end of the scale -- do you need the 10,000 PSI one, or
is a 3,000 PSI one all you need.  The closer to the range of loads you
need the more accurate your readings will be.

    Does the documentation for the forklift list the maximum
hydraulic pressure allowed?  Or the diameter of the piston?  If only the
latter, take that, convert to square inches, and divide into the maximum
allowed load (plus perhaps an additional 500 lbs or so for the forks and
carrier) to see what size you need.


    Have you priced the 10,000 PSI ones at McMaster Carr?  Note that
the glycerin filling is to damp vibration of the needle with the pumps
pulsation.

    Looking at the McMaster Carr catalog, the glyderine filled ones
range beteen $132.00 and $215.00 depending on size (2-1/2" or 4"
diameter) and where the connectionis (bottom, center back or lower
back.  Ahnt it appears to e the same for pressure ranges between 30 PSI
max and 10,000 PSI max.  Expensive enough so you want to calculate the
needed pressure range so you only have to buy *one*.

    These are on the web based catalog page 551.

    And no -- you don't want to use one designed for gas pressures
as a hydraulic gauge.


    I've seen presses for forming something or other at work with
such a gauge mounted on it.  You could also add one to a hydraulic arbor
press ('H' press) or the like.  But you do need to know the maximum
pressure needed or allowed -- and a bit over that so you can tell
between right at the limit and the needle pressing hard against the stop
pin. :-)

    Looks as though there are silicone oil filled ones, as well as
the glycerine ones in the McMaster Carr catalog.

    Good Luck,
        DoN.    

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