Old swivel log / pulp grapple GPM requirenments

[racingjoe66]

Hello guys, I have recently aquired a old log / pulp grapple from a neighbor of mine.  He didn't know much about it and either do I.  I am looking at modifying this to fit onto the end of my 45,000 lbs excavator for placing large rocks around my pond and old trees for coverage for fish and resting spots for turtles.  My excavators pump is 39 gpm @ 3000 psi.

It is what I think is called a knuckle grapple....?  It rotates 360* and does have a stop to from continueing to spin.   Does anyone reqonize this grapple and able to give me any info?  The tines or grapple are 20" wide and 32" tall and 38" wide when closed.  The cylinders are 4".

I am wondering what GPM and pressure I should run the cylinders and also the orbital.  Any and all help would be greatly appreciated.  Also where would be a good place to get parts to rebuild the orbital or at least go through it.

I am also looking at making 2 ears to attach this to my bucket cylinder for more manuverability.  Any pointers?




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[Maine logger88]

That's a prentice pulp grapple off like a G F or 110 series loader by the looks of it. Those loader pumps were 25gpm per section and 2000psi. I wouldn't dare run much more psi than that probably need to rig up a relief. Parts are out there for the grapple cylinders I've done those before. Not sure on the rotor motor I've never had any trouble with ours so far

[racingjoe66]

Thanks for the fast reply Maine Logger88!!!  My plans are to run 2 lines down my boom, a pressure and return to a manifold at the end of the boom with 12vdc directional control valves to control the operation with toggle switches inside the cab for both the cylinders and also the orbital.  This way I have less hydraulic lines run all over till the end of the boom.   I would make sure the manifold has a relief valve cavity in it for a relief valve and also be putting inline reducers to reduce the gpm.   

Where do you get parts for the grapple cylinders?  This thing has been sitting a long time and would like to repack them before hand as well as it looks like one might have a slightly bent ram.  

Hopefully someone can chime in on the orbital.   Do you know what gpm or pressure that runs at on yours?  What I have been able to find online for newer stuff is 20-30 gpm and 2000-2500 psi for a 4" grapple cylinder and 5-8 gpm and maximum 5000 psi for rotor motors.  I can't find anything about older stuff, but I would say it needs to be low like the new ones so it doesn't spin too fast.

Also what size hoses are you running?  My friend says he thought back in the day they had used like 3/8" hose,  these hoses on it look to be 5/8"

Thanks

[Maine logger88]

I just got the packing from a local machine shop. I'm not sure where he got them but he has lots of stuff lol. I am sure that rotor motor won't take 5000 psi that grapple is from the 70s or possibly even 60s. Mine is a bypass but it has the same exact cylinders and a similar rotor. I don't know on the gpm cause I have never gotten into that but I do know the loaders have a tandem pump 25gpm per section. Prentices have 1/2 hoses for both but my grandfathers tree king loader has 1/2 for the grapple cylinders and 3/8 for the rotor

[racingjoe66]

Any chance you could talk with him and see what he would charge for the packing to do both cylinders?  Never hurts to have too much stuff    Yea I wouldn't think 5000 psi either and if the pump was only rated for 2000.....then I would say its most likely around that or less.

With your experience with them, what is your thoughts of mounting it on my excavator with the bucket pin and then also mounting 2 tabs (ears) on it somewhere so can use the bucket curl cylinder to lift the grapple into positions like parallel to the ground?  would that put too much stress on that rotor or shaft you think?

[mike_belben]

Thats a dangle style rotator, i wouldnt fix it on a wrist.  

[Maine logger88]

I believe that would put alot of pressure on it especially on a 200 size excavator like you described that will lift a lot more that the original loader that came on. I would leave it a dangle head if it were mine

[Maine logger88]

Most of the log grapples I've seen put on excavators pin to the boom with the original 2 way link then use the bucket valve for the open close then either a electric valve to also use it for the rotor or plum auxiliary lines for the rotor. Does your machine already have a auxiliary valve and lines?

[racingjoe66]

Kinda my thoughts too about leaving it hang.  Would be nice if it was able to be put on a wrist.  Will 3/8" hose be good enough or does it need 1/2" or 5/8"?   My buddy thought they used 3/8" on one back in the 80's.   All I plan to use it for is place boulders around the perimeter of my pond I am digging and place whole trees in it too for cover.  Then I am building a log cabin over my narrow point of my pond like a bridge and would use it to place the floor joices too.

I had thought about using the bucket cylinder lines to operate the grapple opening and closing which I probably will do now that I am going to leave it dangle.  Then use a 12 volt directional control valve on a manifold to run the rotor with a toggle switch in the cab. 

Will have to do some checking to see about plumbing that manifold and valve into the bucket cylinder lines instead of running 2 small lines the full length of the boom

[Maine logger88]

I had thought about using the bucket cylinder lines to operate the grapple opening and closing which I probably will do now that I am going to leave it dangle.  Then use a 12 volt directional control valve on a manifold to run the rotor with a toggle switch in the cab.

Will have to do some checking to see about plumbing that manifold and valve into the bucket cylinder lines instead of running 2 small lines the full length of the boom

That's what I would do personally! I can ask him about the packing but if I remember right he had to match it up. Where are you located? It's very possible that some had 3/8 lines to the rotor but I do know that all the lines on mine are 1/2

[mike_belben]

You need a 4 port two way DC solenoid valve.  Itll have a pair of A ports and  pair of B ports that can shuttle from a single pair of inlet ports.  Unplug your curl hoses, cap them fittings and plumb the hoses into the splitter valve.  Then two lines to your grapple and two for the rotator.  Itll toggle from the spring return primary to to the solenoid pulled secondary. 

Surplus center and bailey hydraulics, maybe northern toolhttps://forestryforum.com/board/index.php?action=position"> Note:Please read the Forestry Forum's postion on this company will stock them.

For cylinder parts, crossville hydraulics in crossville tn stocks everything.  They manufacture cylinders and replacement parts too.  You could mail them a bent rod and get a new one back.  

[racingjoe66]

I'm located in Iowa.  Let me know what he says.  Worst case, just need to take them off and to a local shop to have them done up.  

Mike_belben   you know a bit more about hydraulics then I do and what is needed to get the job done.  Any help would be great!  Any links to a manifold and valves that would fit the bill would be great.  

Surplus Center is in Lincoln, NE I think isn't it?   I was talking to Bailey earlier today about this, but at that point I was thinking of running lines the full length for auxiliary but that is out of the picture now.  

[mike_belben]

Have a look at this one.  SAE8 is standard for 1/2" hoses.  

12/24 Volt DC 13.2 GPM SAE 8 Solenoid Operated Double Selector Valve | Selector Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com

Your curl hoses plug into port 1 and 2.  A/B would go to your grapple tines and C/D to the rotor.   Wire up a foot style high beam switch and youre ready go, hands free. 

[bushmechanic]

If I was going to just move some rocks with an excavator I would just put a thumb on it and leave the grapple where it is.

[mudfarmer]

If I was going to just move some rocks with an excavator I would just put a thumb on it and leave the grapple where it is.

Just logged in to say the same. Are we missing something?? I would like to know  8)

[racingjoe66]

Awesome, thanks Mike_belben!   So I got it right, would need then 2 switches?  1 switch for the grapple and 1 switch for the rotor? 

I am also moving large full truees with branches and placing them into the pond as well with the roots along the bank to create cover spots for the fish and good fishing spots for the kiddos.  The cost to have someone come out into my field to weld on a thumb would cost more than what I would have into this grapple and putting it on.   I am getting the grapple for $100 bucks

[Oliver05262]

  You are right about the much greater cost of adding a thumb to your machine, but a proper hydraulic operated thumb would be so handy on that size machine that you would wonder how you ever got along without it before. 
  You could do all those jobs and so many more...............

[mike_belben]

One switch.  That solenoid spring returns to the same position every time.  When you feed it 12 or 24v its energize a coil and shuttle the spool to select the other position.  Itll be no different than wiring a headlight.  

[mike_belben]

 Mike_belben   you know a bit more about hydraulics then I do and what is needed to get the job done.  

Thank you.  My daughter has seen me rebuild everything under the sun in her 7yrs of existence, yet right now is telling me over and over how a pen comes apart and goes together. Shes convinced i have never seen this before. 

[racingjoe66]

I am sure a thumb would be nice for sure   I only bought the excavator to initially dig my pond and that was it.  But since had to use it last year to lift the walls of some log cabins my parents tore down and we moved to there place and put back up.  Came in super handy for that!   But other than the pond I have no other real use for this large of a machine unfortantly.  And the grapple will lift big boulders off my car trailer that I put on it with my small skid loader from piles of field rock.  Then use the grapple to carefully lift them off the trailer and place around the pond.   And same for some old trees.

Oh wow Mike that is simple!  Kids will deff keep you on your toes and fixing stuff!!!  My daughter is 16 and my son is 11, so I know all about it, lol.  

For the orbital stop, what would be the best position to have that when mounting on the excavator?   Also I have an extra bucket off the machine so I am able to take that with the grapple to a shop to have welded up a bracket while sitting on the trailer to save a bunch of money there too.

[racingjoe66]

So I got it right with my thinking Mike, the joystick movement for the bucket cylinder would control the opening and closing of the grapple and then the 12 v foot push button high beam switch would operate the direction of the rotor motor?   I might be over thinking this, lol

[mike_belben]

Why does it need a stop?  No extra ports on the rotator to power the grapple?

[Skeans1]

One option for mounting is to hand it off your main bucket pin another is to add a small heel rack which you'd need to use your tool cylinder and dog bone.

[Skeans1]

Normally when we did this your tool cylinder is your rotate, then open and close is on a foot pedal or better yet the switches in the joystick.

[mike_belben]

Sorry i missed your reply above.  

The valve that i linked will not control the motion.. It only controls which component your existing joy stick is coupled to, one or the other.  Say your pattern for curl is right hand stick, left/right motion.  Youve replaced the bucket and plumbed that valve to the solenoid splitter block.  Move the joystick L/R you get rotate CW/CCW .  Push button and move the joystick L/R you get grapple open/close.  Let off button it goes back to rotate.  Or vice versa, thats up to how you plumb it.   But the joystick still does the control, your foot on the momentary switch only dictates which component gets the fluid.  

Think of a train track switcher.  It doesnt control how fast or if the train runs forward or back, only if it takes the left or right lane.


While its possible to make it much more complicated by going to full electrical solenoid control actuating the grapple and rotator, i personally recommend not.   youd lose the speed control capability of the joystick valve.  Solenoids are on/off.. Only one speed.  You can modulate with the hand valve

[racingjoe66]

Thanks Mike, that explains it on the switch and controll for both grapple and rotor!   That is deff simple enough.  Only thing I see then, with the extreme flow my excavator pushes out 39 gpm and looks to be 3,250 psi to the bucket cylinder.   Is there a reducer to reduce the flow before the valve or will the valve be able to do a good enough job of that?   Also will the rotor flow be okay that high?

Thanks for the input Skeans1!    I think I am just going to simply hang it from the bucket pin.  Simple and easy enough

[racingjoe66]

I see the valve says 13.2 gpm max.  

[Don P]

I'm not a hydraulic guru, feel free to correct this. The valve doesn't care that you have 39gpm available, it can only pass 13.2gpm of that. That might be an issue if you were running an auger or something constant. The rest of the time it is off and passing 0 gpm. You will always be feathering that control to swivel in fine increments, more like passing pints per minute. I have an old I'd guess '70's prentice similar to that, it has 1/2" lines and I believe the relief is set at 1500psi.

[racingjoe66]

Thanks Don I'm not a hydraulic guru either lol.  I guess I was thinking the valve had to match the size of the pump...?  Guess just need some clarification on that    

[mike_belben]

I routinely govern down cylinder travel speed with hose size.  If its jerky with a -6 i will put on a -4 for instance.  


The pressure is a more complicated matter and a bit more of a frontier for me.  If you were to let your grandkids go play then yeah theyll hold the valve full open way past sufficient clamping until the hose swells and pops or a seal pukes.  Are you going to do that?  If its only you and youll be taking your time at half throttle and a light touch, then just using small hoses is probably sufficient.  It doesnt RELIEVE pressure like a relief valve, but a restrictor orifice like that will create a pressure drop and it will slow the RATE of pressure rise which means youll be less likely to hold the valve open until the explode point.   This is also the 'do nothing extra' option.  

To do it "right" enough for the liability insurance agent to sign off on your manufacturing these things, would require a relief valve or atleast an adjustment.  Your spool bank may have an adjustable cartridge in it that could lower the force only on that circuit and would be an excellent stroke of luck.  Look hard for this, itll be under a cap or plug inline with that spool section.  Probably with a spring.  Pulling shims or reducing that spring will lower the pressure in that circuit. 

If not youd have to plumb in a relief valve that only effects that circuit, which is made up of an A and B hoses so itd actually take 2 reliefs to be sure. That means a return line needs to be plumbed.  You dont really need to worry about grapple open or rotate, neither of these will build a lot of pressure, but grapple close will.  

 I mean i wouldnt go through all this unless i have employee operators who cant be trained.   Id start with small hoses and redesign after i prove i cant stop it from blowing up.


Speaking of blowing up, you cant double stack differential poppet relief valves on a series circuit and then use both at same time.  So a pair of 2500psi valves that are looking at differential pressure across the two sides.  Well that puts 2500 psi on the low side of one valve so it wont relieve until 5000 psi total and stuff 'splodes.  Its not related to your project, just a general safety warning for everyone.

[racingjoe66]

Thanks Mike.  I am just planing on me doing it or the old man.  I know the kids would love to try it out, but I don't think that will happen.  Maybe just let them dig up a scoop of clay or dirt while digging the pond to keep em happy   But yes would deff be going slow and taking the time unload and move the rocks into place. 

As for the spool bank on the excavator I am about 95% sure there are adjustable cartridges.  As I recall seeing the on schematic some that were and also ranging from 1500 all the way up to 3250 psi.  I will double check but I think there are some   

To plumb in a return line with a relief valve just on the grapple close, that could be done on the boom and just T that return into the main return line there? instead of running it along the whole boom?

[racingjoe66]

I just looked, there are 2 relief valves on the control valve for the bucket set at 3,250 psi.

[racingjoe66]

Says they are a "cartridge type service port reliefs  used in the valves are of the pilot poppet style with external adjustment"

[mike_belben]

Work with the relief valves youve got.  Otherwise youd be adding one all the way out on the stick and then plumbing a return.   You shouldnt really treat either of the A/B ports as a return to tank.  I mean one is pressure and one is exhaust but they switch when you change direction.  Pressure working against the wrong side of a relief exhaust line then.  Check valves maybe?

 I dunno,  It gets muddy from there and isnt an elegant solution.  Working with the oem relief is. 

[racingjoe66]

Thanks Mike!  I will pull apart one of the relief valves that are currently set at 1500 psi and compare the shims count it has to the bucket ones at 3250 psi.  Then change the 3250 to match that and should be set to go    If I can keep from running hoses all the way out, that would be great for sure.  

Glad I found this site and posted on here!!!!!  Wasn't expecting super fast replies and such great help, and I deffinatly appreciate it more than you know!!!

I am also working on an old Bobcat 642B with the auxiliary hydraulics, could use some help on that too if you wouldn't mind....?  

[mike_belben]

Youre welcome joe.  Im here to help.

Does your bobcat have the big hose into the charge pump inlet, or does it have the big aluminum block with tubes and hoses and sensors?  

Whats it doing wrong?

[racingjoe66]

Glad to hear!

It has the auxiliary hydraulics plumbed off the pump into the engine compartment and then capped off from the factory.  From there to the end of the boom was never installed.  I have recently bought a set of the steel boom lines and connectors to put on it.  Where the 2 rubber lines would be installed to connect the 2 steel lines I have bought a Daman manifold block to put 2 D03 12vdc directional valves on to control the auxiliary hydraulics.  The reason for 2 valves is I have a toyota 3 stage forklift mast with side shift onto it.  The side shift is dual acting cylinders and the mast is a single acting cylinder.  So I need 2 lines for the side shift or normal auxiliary attachments and then 1 line only for the mast.  

The manifold I have already bought is Daman # AD03S022S/C  which has a relief cavity for a relief valve.  Needing some help to figure out what valves would be a good choice.  My pump is 10.8 gpm @ 1800-1950 psi.   Also needing some help on the plumbing.  Me and my dad were thinking to run the 1 valve for the mast would just need to plumb the 1 line back to the return line behind the manifold?

[mike_belben]

So your main loader valve under the right elbow only has 2 spools, not 3?  


A 642 is not heavy enough to run a full forklift mast with side shuttle and actually pick anything up.  I actually built my first fork rack with side shuttle from a raymond electric truck i cut up, and never used the stupid function.  Plus, because of it, you cant see a thing through the forks.  I was smashing and knocking things over all the time.  I still have the fork base, id like to sell it.   My machine is a 742 with filled tires and a 1" plate bolted through the back door.  

Im all for the aux hydraulics, wish i had 2 aux spools instead of one.. But the fork mast probably wont be as great as you think. Unless you are frequently loading pallet racks offroad i guess. 

[mike_belben]

Just fyi, bobcat changed the hydraulics on these older machines a bunch so i kinda need to see a pic of yours tocl be sure but its a complicated system and parts are becoming obsolete.

the gear pump is also the charge pump for your hydrostatic drives.  Flow comes out of the gear pump and into the loader valve.  The return pressure from the loader valve is the charge inlet pressure for the drive pumps.  Its critical they have 100ish psi at all times. 

[racingjoe66]

It has 3.  The auxiliarys come right out of it and already plumbed and capped off from the factory.   I am putting wheeled outriggers on each side of the mast for stability.  I already have 250 lbs of counterweight onto the back of the machine and my roof is removeable to be able to view what I am lifting.  I plan on using it to only lift 500 lbs snowmobiles on a pallet to stack them 3-4 sleds high in my storage shed.  Eventually I would like to get a bigger machine and make it more versatile to use.  Hence the reason for putting a quick attach plate on it.

I know a forklift itself would be easier to use for what I am doing, but I already got the machine and figured why not.  Plus if I need to borrow a larger skid steer for it for other jobs that isn't a problem.  Just they wouldn't be plumbed for the side shift which isn't an issue.  I just need that side shift when fine manuevering the sleds into there spots on the pallet racking.   

[racingjoe66]

I have the service manual, so I can get you pictures.  I can scan and post them here real quick, what would you like to see?


 

[racingjoe66]

 

 

[Skeans1]

What machine is this? Make and model?

[mike_belben]

Bobcat 642b


Yeah thats the big port block diagram.  There are two variants.  One with bronze return filter and one without.  Its under the large NPT fitting in the center of the three, they face passenger side.  You ever clean this?  It may not have one but ill await your response.

So if you have the aux valve and your RH steer lever is double jointed then you just need to finish the lines, right?  Whats with the DC parts? 

[racingjoe66]

Nope never had any of the hydraulics apart as never had any issues with it as of yet.  

Yes have the aux valve and RH steer with the bolt keeping it from pivoting. 

The 1 directional control valve was going to control the side shift with a toggle switch on the one hand control and the other DC would control the mast going up or down.  Was told by someone, would need ones like these in this link.

Shopping

[racingjoe66]

If there is a filter there or not, I am unsure and don't recall.  sorry

[mike_belben]

Its called "the hidden filter" 

Most people dont find it until the machine is whining and way down on drive power then they post on skidsteer forum and firat question is 'did you clean the hidden filter?'

Do your mast have a single hose or two for raising it?  Single acting or double acting cylinder more specifically.  

[racingjoe66]

I will have to find this hidden filter and get her cleaned before hand   

The mast is a single acting cylinder,  side shift is a dual acting.

[mike_belben]

Sigh*  alright this is getting complicated.  

Im pretty certain that your machine has load checks on the boom and curl spools but im not certain about the aux spool.  If it does you may need to defeat it in order to lower the mast.  

What youre trying to do is turn a two way spool into a one way spool, which requires connecting the B port to tank and letting the A port be a two way street.  Fluid pumps up the ram and then weight collapses it.  But with load checks, pressure on the B port is required to unseat the load check on port A in order to let fluid back down and lower the mast/boom.  Basically this prevents your loader from drifting down.  It hydraulically locks until you actually press the down pedal, then the lock comes off.  Very common in telehandlers and manlifts etc.  But again i dont know if the aux spool has a check.  


Anyways i think this is about the right way to diagram the aux spool on your machine.  It will do double acting right off the bat, just hook up the two couplers to your side shuttle.  

A/B are your work ports to and from a DA cylinder or hyd motor.  P is from pump and T is to tank.  The top row is labeling your stick position.  Left/spring center/right/detent to far right for motor continuous on. 



To make your DA spool into a SA spool you need a way to connect it to tank.   The simplest, most dependable way is a manual 3way valve.  It will be on the machine with you.  Not out on the attachment.  It must be after the loader valve but before the lines that go up the boom.  And it requires plumbing an extra tank return.  I dont suggest T-ing in with the main line as that is the charge pump pressure line and it has 100 or so PSI in it.  

Anyway all this does is convert your aux spool from DA to SA so it can work the forklift mast cylinder.  It either connects port B to your coupler, or blocks the coupler and connects port B to the tank.  







Okay.  Then to select between mast and side shuttle you also need a 2 way selector valve out on the attachment so that your A/B ports are connected either  to the mast or the shuttle.  It is exactly what we discussed doing on the excavator.  A huge project that will do nothing for you that a regular old fork setup cant.  Personally I would build another sled shed or buy an old clark/hyster/etc before i went through all this effort on the bobcat. 

[racingjoe66]

I will do some checking on the load checks or not as I am not certain either.  

So pretty much could use the same valve as you linked for the excavator for the skid loader?  Just need to run the mast positions B line back to the tank?  

Or would using the manifold I listed with 2 seperate DA valves be better?  

[mike_belben]

In church, will get back to you shortly

[racingjoe66]

Sounds good.    I was doing some thinking lastnight.  I don't think the one like for the excavator would work on the skid loader.  Cause I wouldn't have the control of up or down or side to side.  I would need to use the series manifold I had posted earlier with 2 valves on it.....?  Then I have the independent movement with switches for up or down or left or right.   

[mike_belben]

First off stop saying manifold.  That means a common port that branches to many so its just a big block with holes to common fluid.  You do not need any manifolding whatsoever in any of these projects.  Youre only gonna confuse people you talk to with that word.

Next, you are missing the purpose of what i described with the 3 way selector.  Your aux section is for a two way cylinder or motor ONLY.  Its internal passages are not right for controlling a one way component and what i suggested was an external modification to make this possible.  In hindsight, scratch that idea, its not the most elegant solution for the overall project.  

If you really want to do this forklift thing, buy yourself a forklift or plow pump valve and put a power beyond kit into your 3 section bobcat valve to feed into it.  then plumb those lines up the mast and put on some quick couplers.     Use the bobcat aux valve ports for the side shuttle, and the lift only section of the plow or forklift valve for the fork mast.  The plow/fork valve will also have a two way section remaining.  Use this for your outriggers.  

Its gonna be a lot of plumbing but it will do everything you want with no DC junk on there and no sharing of spools.  Be a tight squeeze.