Thumb Hydraulic thumb for BX23 BH

MadReferee · Jul 11, 2005

The return line from the backhoe goes to tank. If I recall correctly, the inlet to the backhoe is taken from the pressure side just before the 3pt hitch, thus disabling the 3pt when the backhoe is connected.

If you want to connect an additional valve after the bachhoe, the proper hookup method is to add PB to the backhoe valve. Follow these steps: <ul type="square"> [*]Install the PB sleeve into the backhoe valve. The current outlet now becomes the return to tank line. [*]Connect the backhoe PB to your new valve's inlet. [*]Tee the outlet of your new valve together with the outlet of the backhoe valve and connect them to the tractor as before. This is the return to tank circuit. [/list] Your new valve does not need PB since it is now the last valve in the circuit.

Alternatively, if you cannot get a PB sleeve for the backhoe valve, you can get a PB sleeve for your new valve and place it before the backhoe valve. The connections would be the same as above just substitute new for backhoe and visa-versa.

nasdaqsam · Jul 11, 2005

( The return line from the backhoe goes to tank. If I recall correctly, the inlet to the backhoe is taken from the pressure side just before the 3pt hitch, thus disabling the 3pt when the backhoe is connected.

If you want to connect an additional valve after the bachhoe, the proper hookup method is to add PB to the backhoe valve. Follow these steps: <ul type="square"> [*]Install the PB sleeve into the backhoe valve. The current outlet now becomes the return to tank line. [*]Connect the backhoe PB to your new valve's inlet. [*]Tee the outlet of your new valve together with the outlet of the backhoe valve and connect them to the tractor as before. This is the return to tank circuit. [/list] Your new valve does not need PB since it is now the last valve in the circuit.

Alternatively, if you cannot get a PB sleeve for the backhoe valve, you can get a PB sleeve for your new valve and place it before the backhoe valve. The connections would be the same as above just substitute new for backhoe and visa-versa. )

I think I am beginning to understand. WOW, what a long road, thanks for the assistance.

Now with this PB set-up (either one) will the thumb operate at the same time as the other controls or will one have priority over the other? Example: Will I be able to curl the bucket and press with the thumb at the same time?

Also, any advise as to what I need for a sleeve and valve to make this thing work?

One more thing, is it possible to forgo all the sleeve and PB stuff and replace the valve on the machine now with one that would have the extra ports required for the thumb? Example: If the BH has a 6 ports for controls, can I get one with 7?

Thanks for all the help

nasdaqsam · Jul 11, 2005

Actually,

One more thought. (I'm going to hurt myself here). How about just getting the Aux. hydraulic control kit from Kubota and run quick disconnects up to the thumb control on the BH? Would this work? or is the Aux. kit going to be diabled by the BH hook-up like the 3PT. hitch?

Thanks

MadReferee · Jul 11, 2005

( will the thumb operate at the same time as the other controls or will one have priority over the other? Example: Will I be able to curl the bucket and press with the thumb at the same time? )

Maybe, maybe not. It depends on a lot of things. Erring on the conserative side I'd say probably not. With multiple valves the first valve in line normally has priority for flow. On a valve with multiple spools it would depend on the internal design of the valve.

( One more thing, is it possible to forgo all the sleeve and PB stuff and replace the valve on the machine now with one that would have the extra ports required for the thumb? Example: If the BH has a 6 ports for controls, can I get one with 7? )

This is the ultimate option, if you can find the right valve that will fit. Surplus Center has an 8 spool valve that is configured correctly but will it fit is the question. They also have the Prince SV which is a configure your own valve where you specify what spools you want. Call Surplus Center and ask for technical assistance (1-800-488-3407).

MadReferee · Jul 11, 2005

( One more thought. (I'm going to hurt myself here). How about just getting the Aux. hydraulic control kit from Kubota and run quick disconnects up to the thumb control on the BH? Would this work? or is the Aux. kit going to be diabled by the BH hook-up like the 3PT. hitch?)

It would work but it is no different than having 2 valves on the backhoe. In an open center system all valves are in series and the normal plumbing method would place the aux valve before the backhoe in the circuit.

nasdaqsam · Jul 11, 2005

Thanks again,

I will call the surplus center tomorrow.

As a note:I took the cover plate off. The valve is a Nabtesco from what I can see of it. Now on the in/out side there is a block the lines connect to and several plugs, then a series of control modules, now I say modules because from the look of the valve it appears you can just add another one on if needed, although that may be appearance only. On the opposite end there is another block with several plugs in it that looks just like the in/out block but nothing hooked up to it.

Is any of this info helpfull?

MadReferee · Jul 11, 2005

From what I could find on the internet, Nabtesco is a large Japanese conglomerate that specializes in robotics and other mechanical systems. The valve is probably proprietary and made just for Kubota. I don't think you will find additional spools or any other information on that valve other than what is in the backhoe manual.

Your best bet is to either add on another valve or replace the existing valve with one that will fit and has the number of spools you want.

However, you can always get an electrical diverter and connect it to one of the spools that work the stabilizer arms. You can connect it similar to what others have done with a front grapple. This might be a reasonable inexpensive alternative to adding a new valve with all the associated plumbing hassles.

Good luck.

nasdaqsam · Jul 11, 2005

Thanks again,

I did a search on the company also and found their hydraulic division which is part of another larger division. Anyway I found an e-mail address for customer inquiries and sent one for the heck of it. Probably will never hear from them.

My Kubota rep. has a call into his contact and is checking to see if we can add one more spool to the assembly. He said when one spool goes bad he thought they only chnged that part and not the whole valve. If that is the case maybe we can just add one on. He is going to let me know tomorrow.

I had read of a couple people doing the electric valve thing but I tried a few searchs and came up empty on how to actually do it. Anybody have a link on how to do it?

Thanks again for all the help.

HomeBrew2 · Jul 11, 2005

Pineridge sure has links to his successful use of the diverter valve ...

davesisk · Jul 11, 2005

( Thanks again,

I had read of a couple people doing the electric valve thing but I tried a few searchs and came up empty on how to actually do it. Anybody have a link on how to do it?

Thanks again for all the help. )

Sounds like you're talking about a double selector valve...there are both manual and solenoid-operated. These are pretty simple, they go between the directional control valve and the cylinder it controls. For instance, take the spool that controls curling and uncurling the boom. You would remove the two hoses to that cylinder, connect them to the input ports of the selector valve, then connect hoses from the default outputs of the selector valve to the original cylinder. You then have two additional output ports from the selector valve, which can go to your thumb cylinder. You either pull the plunger (manual) or push a thumb button or switch (electric) to operate the thumb rather than the boom. Think of a selector valve just like one of the Y-adapter that you can put on a outdoor water hose tap...you turn a little lever to send water to one hose or the other. Same idea.

Manual double selector valves can be had for under $80. See here:

http://www.surpluscenter.com/item.asp?UID=2005071120520178&item=9-5173&catname=hydraulic

http://www.surpluscenter.com/item.asp?UID=2005071120520178&item=9-6238&catname=hydraulic

There's also at least one electric solenoid-operate double selector.

http://www.surpluscenter.com/item.asp?UID=2005071120520178&item=9-1782&catname=hydraulic

You just wire a switch to the poles on the selector and to a battery + source (ignition switch or something similar), could be a momentary contact pushbutton or a toggle switch. If using a pushbutton, mount it on valve handle that you've used for the control so you can switch between the two different targets with your thumb.

Here's a link to the old Power-trac I used to own...toward the bottom there's a hydraulic diagram showing the selector valve install hookup.

http://www.ipass.net/davesisk/tractor.htm

I really like the selector valve approach for it's simplicity. The only drawback is that you can't operate both of the cylinders at the same time, only the selected one. However, you can choose which cylinder is going to "share" with the thumb cylinder. Would you ever move the boom and thumb at the same time for instance? Probably not.

HTH,
Dave