using a pressure guage as a scale.

[the old grind]

.. and as the cylinder extends, the rod is pulled out, and oil above or below the piston will ...?

(a-expand according to Froidberg's Law
(b-leak out as the cap is removed and air enters.
(c-soak and ruin two 80lb bags of feed

See, simpler is better. Ya just have to do the math.

Engineers are the guys with clean hands and a stack of papers, right? We go by their prints to the letter, but they ask questions once in a while.

 

[Dave M7040]

.. and as the cylinder extends, the rod is pulled out, and oil above or below the piston will ...?

(a-expand according to Froidberg's Law
(b-leak out as the cap is removed and air enters.
(c-soak and ruin two 80lb bags of feed

See, simpler is better. Ya just have to do the math.

Engineers are the guys with clean hands and a stack of papers, right? We go by their prints to the letter, but they ask questions once in a while.

This engineer does not have clean hands but rather cracked and bent ones with dirt under my nails!

This is more simple than you understand. It is a static device with no movement that you could detect! The only movement will be the Bourdon tube within the gauge moving the pointer.
The oil above the piston does not move as you certainly know, fluids are in-compressible. The movement will be so small you could not measure it without a very high quality metrology dial indicator.

You don't need any oil below the piston.

Of course this is a more complicated and expensive way to use a pressure gauge compared to bcp's crane scale for about $100

My idea only makes sense if you have stuff kicking around such a a good cylinder of short length and small diameter + a pressure gauge.

Dave M7040

 

[the old grind]

Honestly, sir, I suggest that your idea is a darn good one, esp because reliable and repeatable results would be endemic.

And yes, some of us do have gauges and cylinders to outnumber any unassigned c-notes.
btw, I appreciate that you weren't offended by my silliness. :drink:

Y'know, I have to laugh at myself sometimes, b'cuz I have three FELs that won't budge a mere 1k lbs. .. :laughing:

 

[4570Man]

If you wanted to chain everything like any kind of actual scale requires you could probably get pretty accurate results with the loader. Hook the chain at the same spot and use a long enough chain to make a full height lift. Just don't bottom out the cylinders because that increases the pressure.

 

[Dave M7040]

Honestly, sir, I suggest that your idea is a darn good one, esp because reliable and repeatable results would be endemic.

And yes, some of us do have gauges and cylinders to outnumber any unassigned c-notes.
btw, I appreciate that you weren't offended by my silliness. :drink:

Y'know, I have to laugh at myself sometimes, b'cuz I have three FELs that won't budge a mere 1k lbs. .. :laughing:

First let me start by apologizing for getting a bit testy with my posts.

I am up at 1:30 am because of nightmares from PTSD. I worked as a accident investigator for the Canadian Government looking into motor vehicle accidents. Now in my 70's, I can no longer be active enough to keep these memories in the back of my mind
I was in the field with the guts and brain matter where I was working. The Engineer behind a pile of papers just did not fit my reality.

Back to the matter at hand. Using a cylinder is simple but if you use too large a diameter cylinder you will have a hard time seeing a difference between 80 lbs and 90 lbs. Pressure gauges come in many levels of accuracy and repeat-ability. A 3,000 psi gauge of reasonable price, with have an accuracy of + or - 1.5%, which equates to 45 lbs, is not going to be too helpful for you.

The retract area of the cylinder could be filled with plumbing antifreeze. Propylene glycol is used in some foods as a sweetener so any spill would not be harmful.

What Is Propylene Glycol?

Propylene glycol is derived from petroleum and is a viscous colorless, odorless substance with a sweet taste. Food makers value it for its ability to keep a substance moist, maintain texture, and mix with almost anything (oil, alcohol, and water). Because of these properties and because it is generally recognized as safe, it has become a common food additive in processed or ready-made food items.

Processed food items containing propylene glycol are typically foods that require thickening, emulsifying, or stabilizing properties. These include:

Salad dressing
Liquid artificial flavoring
Ice cream
Artificial sweetener
Icing
Soft drinks
Soups
Puddings and desserts
Sauces and dips

Propylene glycol is also often added to body care products, cosmetics, and medications.

Dave M7040

 

[LD1]

I'd like to put a pressure gauge on a JD 542 tractor loader to use as a scale to get a rough guide as to what large bulk bags of oats might weigh. I figure that will be better than a guess. Once I do some testing with some bulk fertilizer bags of known wt. and some known 50 lbs sacks of feed. So I figure that I should be able to weigh up to 2000 lbs using a pressure gauge. The 542 loader has two lift cylinders with a guess of 1 sq. inch each so I should be able to lift 2000 lbs with about 1000 psi. I don't want to take the cylinders apart to get the exact sq inch but I shouldn't have to. I know the loader lifts the ton bags of fertilizer but I have no idea of the pressure. Some of you guys have a lot of experience and I have none. Any idea which gauge to use or how much abuse a gauge can take. I was going to try a 3,000psi oil filled one But maybe that is to high. Will the gauge break if I stop it to fast on the way down and cause a spike in the pressure? Any ideas will be a help.

You simply do not have an understanding of how loader hydraulics work.

I would guess the cylinders to be at least 2" in diameter if not a little more. most likely 60mm cylinders.

So no idea where you are coming up with the notion that you think they have 1 sq in each. Try alot closer to 4 sq inches each.

So yea....your cylinders (with two of them) are pushing with a combined force 20,000# or so.

But with cylinders on an angle, and the loader as a whole being a big lever that puts the cylinder at a disadvantage (geometry and all that) is why you aint lifting 20k......rather 2-3k

You simply need to do what I suggested in the PM. Put a gauge on it, load a known weight, make note.

It sounds as if you are wanting to weigh bags of seed (assuming on a pallet). That works out well. Pick up a pallet that you know is a ton of seed (evenly distributed). You should get a reading on your pressure gauge.

Now take an empty pallet, put sacks of oats on it til your at that same reading.....and yep....thats about a ton.

 

[pmsmechanic]

Front End Loader Scales

FARM SHOW - Weigh Scale for Front-End Loader

Somewhere I have an article on how to attach and calibrate a pressure gauge to use as a weight scale on a front end loader. It wasn't really really accurate but from what I understand that's not what you want. I looked for the article but I can't find it but the jist was that you lift you loader arms to a repeatable spot with a known weight and note the pressure. Always lifting to the same position lift several different weights and develop a weight/pressure graff. That should get you close enough for what you want to do.

The important parts are to T into the lift arms and always lift the load to the same position.

 

[4570Man]

You simply do not have an understanding of how loader hydraulics work.

I would guess the cylinders to be at least 2" in diameter if not a little more. most likely 60mm cylinders.

So no idea where you are coming up with the notion that you think they have 1 sq in each. Try alot closer to 4 sq inches each.

So yea....your cylinders (with two of them) are pushing with a combined force 20,000# or so.

But with cylinders on an angle, and the loader as a whole being a big lever that puts the cylinder at a disadvantage (geometry and all that) is why you aint lifting 20k......rather 2-3k

You simply need to do what I suggested in the PM. Put a gauge on it, load a known weight, make note.

It sounds as if you are wanting to weigh bags of seed (assuming on a pallet). That works out well. Pick up a pallet that you know is a ton of seed (evenly distributed). You should get a reading on your pressure gauge.

Now take an empty pallet, put sacks of oats on it til your at that same reading.....and yep....thats about a ton.

I understand how a tractor loader works, and yep it's at a big mechanical disadvantage. I've been wondering if you used a forklift instead what would happen when you changed the distance from the mast. Assuming the forklift doesn't tip forward or the fork doesn't bend ( that's what's actually going to happen) will the machine lift the same amount at the tip of the fork as the back of the fork?

 

[LD1]

will the machine lift the same amount at the tip of the fork as the back of the fork?

Yes it will. There is no leverage over the cylinder (lift cylinder that is) by moving the load further forward.

Tilt cylinders are a different story. Further out or higher up and their capacity is reduced

 

[Industrial Toys]

Curious to find how it worked. I have been looking for a used loader scale for a while. I can't imagine they work any different. Just a pressure transducer in the loader lift line. I don't think there is any loader position sensor. I could be totally wrong.

I'm guessing that the issue with using a gauge might be the lack of resolution. In fact, I am almost certain this will be the case. On a 5000 # gauge, you won't see that feed bag weight difference. You MAY see a bucket full of aggregate.