Grapple Grapple clamp preasure

[dirt clod]

I got one of andy tatro's grapples. It clamps down fine for brush. The property I have was left with a bunch of junk and a few buildings in need of demo. If I try to pickup something other than brush it does not have enough clamping power to hold it. Items like loose roofing tin it will not crush into the bucket. acts like the bypass valve on tractor is opening, but I'm running higher than stock preasure. Tractor has plenty of lifting power.Also I have problems with it getting locked up when I drive into brush with it fully open, if it gets bumped back a little more open it gets past the centerline and jams. I know this is a great product and Andy is a great guy to deal with as such I'm not complaining about the product.

Anyone have ideas on the like of clamp preasure and locking up?
It has a 2"x6" cylinder should I go up to a 3"?

 

[kennyd]

A larger cylinder will help, but are you sure the bottom of your bucket is not bowing?

 

[RonMar]

I don't think I have seen any pics of a Tatro Grapple, but the geometry on some designs dosn't leave much available force at the tines/teeth. Do you have any pictures of your installation? If you do, and can tell me the pressures and cylinder size you are working with, we can probably calculate the available force out at the tips of the grapple teeth.

 

[dirt clod]

A larger cylinder will help, but are you sure the bottom of your bucket is not bowing?

It wouldn't have the preasure to do such. It will not crunch into old sheet metal enough to hold it!

 

[dirt clod]

Pictures on andy's sight here: http://www.tatrosite.com/Customer_Pictures.html

It's to dark to get pictures of mine installed now. I think the arms are 27 1/2" and the cylinder is a 2"x6"

 

[3RRL]

Quinton,
What kind of valve are you using to control it? Sounds like there's not enough pressure to make the cylinder work to me, so I'd check the valve too. Is it a diverter valve you have or a true third function solenoid valve?
You know I have Andy's bucket grapples (two) on my 72" bucket. That's my tractor on his home page in the lower left corner with the dual red grapples. Also in the right top corner on the 3rd "Grapple Pics" page with that giant log in it. I have tons of pics using the grapples.
(Ron, I know you've seen some of those before in other threads.)

I've heard of them going back too far and locking up, but I've never had it happen to me. Not only that, mine have plenty of holding/crushing power so I don't know what to tell you other than check the valve controlling it. Heck, it might be the cylinder too if it's got a leaky "O" ring seal? Do you have a pressure gage to check your system?

 

[dirt clod]

Put a guage on cylinder. When I'm closeing the grapple the other port on the cylinder builds preasure up as the cylinder closes. Could it be the selector valve I'm useing?

Another weird thing is if switch around the hoses on the grapple cylinder it acts like it is stuck once it shuts it will not open. Any ideas????????

I've talked to Andy , he's not sure what the problem is. I do know its not a problem with his product though. He has been very helpful.

 

[kennyd]

Put a guage on cylinder. When I'm closeing the grapple the other port on the cylinder builds preasure up as the cylinder closes. Could it be the selector valve I'm useing?

Another weird thing is if switch around the hoses on the grapple cylinder it acts like it is stuck once it shuts it will not open. Any ideas????????

I've talked to Andy , he's not sure what the problem is. I do know its not a problem with his product though. He has been very helpful.

OK, It sounds like the valve controlling the grapple has a Regenerative circuit built into it, common on loader control valves. Read more about that HERE.
-OR- the seals in the cylinder could be bad allowing the fluid to bypass them.

You need to be more descriptive please:

Where did you place the gauge?
How are you controlling the grapple, Diverter-Solenoid Valve-or separate spool valve?
What pressures did you see?


Testing the cylinder seals is messy, but easy: Remove one hose from the cylinder, the operate the control valve to pressurize the other hose and see if any fluid comes out of the open port on the cylinder, then repeat test for the other port (switch hoses) If you get any fluid from the open port then the seals are bad internally causing your problems.

 

[dirt clod]

kennyd many thanks. It makes sense why it is doing what it is.
I did check the cylinder no blow by at all.
my post on the selector valve and how I installed...... http://www.tractorbynet.com/forums/hydraulics/120482-selector-valve.htm

I thought others used a selector valve on these tractors ok?
Any ideas on what I should do?
Install some sort of tank inline to cut down on the volume of fluid?

 

[kennyd]

OK, now I remember...you used that 3 position diverter.

I have no idea what to say except this:

If it is the regen circuit that's causing the problem then you need to figure out how the activate the joystick without hitting the regen...
Like on my JD-the regen is at the far right of the travel only, so if I don't move the stick all the way right then it does not go into regen mode. There is even a lockout at the linkage to keep it from going into regen if I want to lock it out completely.
I am not sure how the Kubota (Husco) valves deal with this...but there must be a way?