Anyone changed their hydraulic cylinders on their grappler for more grab.

[4570Man]

So I now get the confusion, you folks do not understand that the measurement force discussed and referenced is psi = pounds per square inch. It matters not if the psi is applied to 10 square inches or 100 square inches. It is still measured and expressed in psi, just like the pressure gauge shows. That equalizes size. Difficult concept when you refuse to acknowledge the unit! PSI is a fairly standard measurement in pressure! And again size foes not change psi nor does volume!
Just wow!

You still don’t understand. What is supplying this mythical pressure you keep talking about? You apply 2000 pounds of actual pounds not pressure to your grapple lid. The grapple lid and cylinder works at a 3/1 mechanical disadvantage so you’re pushing 6,000 pounds of force against the cylinder. The cylinder rod area is 2 inches. 6000 pounds over 2 inches is 3,000 psi generated. If you increase the cylinder area without changing anything else the load is distributed over more area and the psi is less. Again how would tracks or snow shoes work if they’re still applying the same psi? You could push a pencil in the ground pretty easy by hand. Try again with a 2x4 and see how it goes. Your hand pressure of say 50 pounds is a lot over the small area of the 1/4 diameter pencil. 50 pounds over the much larger 2x4 isn’t very much.

 

[4570Man]

This pencil that you easily pushed in the ground with 50 pounds of force is 1/16 of a square inch. ( this is a square pencil vs round ) the 50 pound applied over that small area is 800 psi. The 2x4 that you were completely useless against pushing in the ground was 8 square inches on the end and the same 50 pounds is only 6.26 psi. You’d need 6400 pounds pushing on the 2x4 to generate the same 800 psi the pencil did. Before you make some lame comment about sealed and back pressure it makes no difference. Of course the cylinder is sealed the oil would just spray out of it wasn’t. 2000 pounds pushing on a 2” area rod in a sealed cylinder of oil or the same rod pushing against a concrete floor makes no difference. It’s still 1000 psi.

 

[Smokeydog]

Most folks will agree a larger cylinder would increase the clamping force (F). F = tractor hydraulic psi x surface area of cylinder piston or rod.

The Messicks video demonstrates that a external force like a log prying on a lid can increase the clamping force by increasing the cylinder pressure as shown by their gauge.

F = psi x surface area, is still true.

For a given force (F) if the surface area from a larger cylinder goes up the psi goes down.

Most entertaining problem.

 

[ruffdog]

4570man....I think you are describing the line pressure needed to do a fixed level of work. A bigger cylinder would use less line pressure to the same work as a small cylinder would need. The problem being is the line pressure from the pump is fixed (non-variable) in most cases. Once the grapple lid is stopped mid stroke, then the calculated pressures comes to play. One comment on the Messicks video, a larger cylinder would lessen the system pressure amplified going back to the tractor when an operator pries with the grapple lid.

 

[4570Man]

4570man....I think you are describing the line pressure needed to do a fixed level of work. A bigger cylinder would use less line pressure to the same work as a small cylinder would need. The problem being is the line pressure from the pump is fixed (non-variable) in most cases. Once the grapple lid is stopped mid stroke, then the calculated pressures comes to play. One comment on the Messicks video, a larger cylinder would lessen the system pressure amplified going back to the tractor when an operator pries with the grapple lid.

Which is exactly what we’re arguing about. A certain member who hasn’t replied since yesterday is insisting that the bigger cylinder would produce an equal back pressure as the smaller one.

 

[homesteader13]

Anyone changed their hydraulic cylinders on their grappler for more grabbing / Crushing power.

On my grappler more often than not when I got to pick up something bulky/heavy the grapple doesn't hold it's grip. It's like that crane game you played as a kid and try and gran that watch but the watch is just too heavy to be picked up by that claw and drops it.

Any thoughts on going bigger with the cylinders?

I have a Hawse dual lid rock/ brush grapple.
It had 1/4 or 3/8 hoses on it when I bought it, (I dont remember exactly which at the moment) I am operating the clamps with lines running from my rear remote instead of a 3rd function.
Awhile back I damaged ine of the hoses on the left lid and had new hoses made for BOTH lines on the left cylinder out of 1/2 inch because they are heavier and less floppy than the smaller ones and figured I would do the same with the right side when the time comes they need replaced.
What I did find out by doing this is that now the left lid operates faster than the left side and seems to clamp harder as well. IE, the left lid closes fully faster than the right side and also opens faster.
So for what its worth, it seems to be more efficient both time wise and clamping force wise that will be even more improved when I replace the other side with 1/2 hose too.

I was using this grapple after the floods in the midwest last year and ev3n with the small lines on it, I could pick up two couches sitting side by side from the ends with the rest of them sticking 6 feet past the grapple and clamp them down, crush the ends and lift them into the dumprtucks without losing any clamping force. Same for 2 refrigerators lifted in the same manner.

 

[ruffdog]

I'm running a 1/32" restrictor on my grapple to slow it down. It does not limit pressure as it still clamps just as hard.

 

[4570Man]

I'm running a 1/32" restrictor on my grapple to slow it down. It does not limit pressure as it still clamps just as hard.

I’m not sure why you’d want to but you’re right it clamps just as hard just slower. A lot of people don’t seem to understand but volume and pressure are completely separate with hydraulics.

 

[homesteader13]

The way I work, I like the faster operation of the larger lines, fortunately, I've never had clamping issues or bleed off once clamped.

 

[ruffdog]

I would assume that the toolcat is putting out plenty of GPM and the restrictor controls the speed so the lid doesn't slam open/closed.