iDRY Vacuum Kilns

Sponsors:

Grapple skidder theory?

Started by Satamax, July 31, 2018, 04:33:04 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Satamax

In this video, you Can well see the advantage of the rotator on the grapple, around thé 3.20 minute mark. 

Grapple Skidder CAT 525C - YouTube

But, when turning left and right, with trees behind,  you need the rotator to freespool i would think. 

How is this done? 

Thanks
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

DDW_OR

i am very GREEN about Hydraulic parts.
but would a Relief or Cushion Valve work?
"let the machines do the work"

Skeans1

Pressure is only applied when the valve handle or joystick is pushed in the desired direction otherwise they're free moving, on our tsk D4H the grapple can be rotated by hand as long as the valve is in neutral.

kiko

This is where the rotate action goes down, notice how the open close passages are cast into the spindle .

 

This is the rotate motor itself. It is a radial hydraulic motor.


 

The 525C is my favorite with out a doubt.  Major draw backs to them is no declutch and having to twist in the seat to see out the back.  In the video you can see him all twisted backing out. Fine machine though.  Here is a single arch C.



quilbilly

What's the advantage to declutch?
a man is strongest on his knees

kiko

It is not good to be stalling over the converter while holding the service brake and throttling to speed hydraulic function.  Constantly doing that will cause premature transmission failure. So the transmission need be in nuetral when stopped, working grapple function.

Maine logger88

He's not going to be happy when the grapple gets caught up in a chain leaving it open and driving around. I guess having a good snubber helps but it still will happen eventually. My old 240 the snubber is completely worn out so you have to grab the arch or it will get tangled up pretty quick 
79 TJ 225 81 JD 540B Husky and Jonsered saws

Satamax

French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

mike_belben

Max, you will be using a motor spool to control the rotator.  The A and B ports connect to each other in the neutral position allowing the motor to have a metered float.
Praise The Lord

Satamax

French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

DDW_OR

Quote from: mike_belben on August 01, 2018, 07:47:53 AM
Max, you will be using a motor spool to control the rotator.  The A and B ports connect to each other in the neutral position allowing the motor to have a metered float.
please explain?
I am adding a grapple and rotator to my bobcat 331 excavator
the thumb will work the grapple and i will put a manual 3-way valve on the bucket cylinder to operate the rotator
3/8" NPT Carbon Steel 5880 PSI 3-Way Ball Valve | Ball Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com
will remove the handle during use. and weld a protective bracket
"let the machines do the work"

mike_belben

Well, in the case of a grapple skidder you want to be able to power rotate to orient your jaws on the log, but when hauling want a free float like a trailer hitch.  A cylinder spool valve would lock the rotator when not being used and create resistance in turns.  It'd chew up logs and maybe break stuff as well as make turns harder.  This is what max needs, a motor spool. 



 It just allows the fluid in the motor circuit to circulate within the motor so that rotation is allowed, like a loader float.  On cylinder spools A and B are isolated from each other to prevent drift. 
Praise The Lord

mike_belben

For your excavator grapple i think youd be happier with double selector valves on the stick, whether manual or DC.  Manual is obviously more dependable and no wire to plumb or tear.   Surplus center has quite a few and they have PDF tabs on how to set them up. 



If youre gonna go with 3 way ball valves, youll need 4, one for each line.  I dont know what type of spool knuckle booms use, i'd imagine a cylinder spool and relief cartridge so nothing gets busted if a log decides it must spin the rotator.  Your conversion will work fine for part time log loader needs im sure. 

Just remember its a pain to bleed air out of cylinders so use quick couplers instead of swivels.. That way you dont take on air with every switch. 
Praise The Lord

Satamax

Quote from: mike_belben on August 01, 2018, 03:49:45 PM
Well, in the case of a grapple skidder you want to be able to power rotate to orient your jaws on the log, but when hauling want a free float like a trailer hitch.  A cylinder spool valve would lock the rotator when not being used and create resistance in turns.  It'd chew up logs and maybe break stuff as well as make turns harder.  This is what max needs, a motor spool.



It just allows the fluid in the motor circuit to circulate within the motor so that rotation is allowed, like a loader float.  On cylinder spools A and B are isolated from each other to prevent drift.
Got it! 
It's not the explanation, but the drawing A cross, a link, and a straight, i understand that!  ;D
Thanks a lot Mike. 
And i'm still making no progress, due to the fact that i can't buy parts! Dang France, with it's taxes! 
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

mike_belben

Btw they do make add on float spools too, incase you have a need for lock and float. 
Praise The Lord

Skeans1

Quote from: DDW_OR on August 01, 2018, 11:46:46 AM
Quote from: mike_belben on August 01, 2018, 07:47:53 AM
Max, you will be using a motor spool to control the rotator.  The A and B ports connect to each other in the neutral position allowing the motor to have a metered float.
please explain?
I am adding a grapple and rotator to my bobcat 331 excavator
the thumb will work the grapple and i will put a manual 3-way valve on the bucket cylinder to operate the rotator
3/8" NPT Carbon Steel 5880 PSI 3-Way Ball Valve | Ball Valves | Hydraulic Valves | Hydraulics | [url=http://www.surpluscenter.com]Surplus Center[/url]
will remove the handle during use. and weld a protective bracket
Same machine that you're adding a dangle head to correct? If so you'll normally use the link cylinder plumbing for rotate, then you could use the thumb for open and close.

DDW_OR

yes, but i was going to put the 3-way on the bucket cylinder lines. that way the joystick movement does the rotation. the auxiliary line that would normally operate the thumb will do the grapple open/close.
Parts list
qty 2, 3-way valves
qty 4, hydraulic lines
qty 4, quick connects
plus adapters and protective frames
"let the machines do the work"

mike_belben

It would take 4 three way valves.  Two cylinders each with an A and B port.  Thats why i was suggesting the double selectors, itd be a bit cleaner packaging.
Praise The Lord

DDW_OR

"let the machines do the work"

setnctl

the way the grapple rotate "floats" so to speak is with a crosser relief valve
 

mike_belben

Meaning it lets A and B port connect when relief pressure is achieved?   So they use a cylinder spool and the relief makes it act like a motor spool briefly when needed?

Praise The Lord

setnctl

yes that's how it works and most of the cross over relief valves I've worked on are adjustable by changing the shim set in the valve

DDW_OR

Here is how i set up my grapple and rotator
i disconnected the two hydraulic lines from the bucket cylinder.(A0 and B0)
then re-connected them to the inputs of the three-way-valves.
then added two short lines back to the cylinder. (A1 and B1)
then ran two long lines to the rotator. (A2 and B2)

i position the bucket cylinder so the adapter plate for the rotator is in a "good" location. then manually switch the three-way-valve to position 2. this bypasses the bucket cylinder and locks it in place.

now the joystick movement that would normally operate the bucket now operates the rotation.
and disconnect the thumb and connect the grapple to the auxiliary hydraulics.




 


"let the machines do the work"

Thank You Sponsors!