Custom hydraulic backhoe thumb

[dfkrug]

I'm really looking forward to the "pinch" thumb. My main use for the thumb will be picking up logs to cut for
firewood.

Think of it as a grapple.

Most of my use is to pluck rocks out of my diggings (trails, mostly). I also lift and stack heavy logs that I
cut and save for future splitting. If I want to pluck a rock or log off of a hillside or stack where I reach out with
the boom/dipper, I must close the thumb first, then turn it off. Gravity favors thumb movement when
the boom/dipper is in this position.

Of course, I can position and fix the thumb in any position before I reach out with the boom/dipper. All from
the seat.

I should take some videos. (My web page and all its links have been deleted last month by Verizon.)

 

[avc8130]

Think of it as a grapple.

Most of my use is to pluck rocks out of my diggings (trails, mostly). I also lift and stack heavy logs that I
cut and save for future splitting. If I want to pluck a rock or log off of a hillside or stack where I reach out with
the boom/dipper, I must close the thumb first, then turn it off. Gravity favors thumb movement when
the boom/dipper is in this position.

Of course, I can position and fix the thumb in any position before I reach out with the boom/dipper. All from
the seat.

I should take some videos. (My web page and all its links have been deleted last month by Verizon.)

YouTube needs videos of this!

 

[kennyd]

Assuming I was comfortable running 1/4" lines from the operator station to the thumb cylinder, what "easy" options are there for installing a simple control valve that would permit independent operation of that cylinder? I wonder for example what it would take to parasitize one of the stabilizer lines (diverter valve?) that would leave the stabilizer in position while flow was diverted temporarily to the thumb. My understanding of hydraulic valving is really pretty naive so that might not be the reasonable approach. It seems however that there might be some home made solution intermediate between the now famous "dfkrug simultaneous operation" set up and the $1800 kit offered by Woods for independent control. Is a two spool solenoid valve necessary (seems to cost about $250 on surplus supply) or could a simple mechanical "solenoid" be used to divert flow to a separate control valve? As one would rarely adjust stabilizers once set, it seems plumbing something that would allow physically turning a valve from A to B at the operator station to divert flow might allow use of the stabilizer control itself to control the thumb. Is that nuts?

It's not nuts at all, I have sold electric diverters for that use before. Its no different than using a diverter to control a grapple on the FEL.

 

[IslandTractor]

It is completely feasible, IT.

You can get a 6-way, 2-circuit lever-operated diverter that would use flow from one outrigger. That WOULD reduce
your hoses along the boom to 2, and that's good.

I did a quick check and a manual diverter like this runs over $100, so it does not save much money vs. solenoid
diverters for the same task. If you put your solenoid diverters down near the operator, then you have more
flexibility re size and shape. I think you would get tired of manually switching whenever you had to move.

So....consider this valve, from the HydraForce catalog. One solenoid, six-way:
SV12-60 Spool-Type 2-Position, 6-Way Hydraulic Cartridge Valve

Not small in size, and I do not know what it would cost. You have to ask a disti.

Looks like an expensive valve. Thanks for thinking that through though.

One other thought: As I have two rear remotes on the tractor and use one for the BH, the other (generally hooked up to the topping lift) is not used whenever the BH is mounted. Could I rig a simple system to operate the thumb that feeds off my extra rear remote but allows me to control from the BH operator station rather than from the driver seat? I suppose I could rig a very klutzy mechanical rod that I could turn and reach to operate the standard mechanical valve at the tractor seat but I presume I could simply turn that circuit on and then control from a simple valve at the BH operator station if I could figure out what type of valve would do that. Probably the type of valve a log splitter would use. Running 1/4" line out the boom would be pretty easy and I think 1/4" would be fine for the thumb. Pretty cheap too so long as I use standard lengths from Surplus Center and just coil the extra under the operator station.

 

[avc8130]

Looks like an expensive valve. Thanks for thinking that through though.

One other thought: As I have two rear remotes on the tractor and use one for the BH, the other (generally hooked up to the topping lift) is not used whenever the BH is mounted. Could I rig a simple system to operate the thumb that feeds off my extra rear remote but allows me to control from the BH operator station rather than from the driver seat? I suppose I could rig a very klutzy mechanical rod that I could turn and reach to operate the standard mechanical valve at the tractor seat but I presume I could simply turn that circuit on and then control from a simple valve at the BH operator station if I could figure out what type of valve would do that. Running 1/4" line out the boom would be pretty easy and I think 1/4" would be fine for the thumb. Pretty cheap too so long as I use standard lengths from Surplus Center and just coil the extra under the operator station.

You could get another valve similar to your rear remote and mount it on your operator station. Then hold your rear remote open and use the new valve to control the thumb. You'll have hydraulic lines running all over your machine, but it would work.

ac

 

[dfkrug]

Looks like an expensive valve. Thanks for thinking that through though.

I hope someone gets a quotation. It should be way less than the usual 2-solenoid spool-type diverter/
selector sold by the likes of WRLong. That's the type that requires the purchase of a manifold, too. The
HydraForce unit is a monoblock that does not.

 

[dfkrug]

One other thought: As I have two rear remotes on the tractor and use one for the BH, the other (generally hooked
up to the topping lift) is not used whenever the BH is mounted. Could I rig a simple system to operate the thumb
that feeds off my extra rear remote but allows me to control from the BH operator station rather than from the driver
seat?

I assume you have the 2 AUX spool valves from the factory. One is detented and the other is not, correct? Both
situated on the right side of the seat, as on my CK30?

You can not use your 2nd AUX valve to power a thumb if the 1st one is used to power the hoe, since no fluid gets
to the 2nd one while the first is detented in the ON position.

 

[IslandTractor]

I assume you have the 2 AUX spool valves from the factory. One is detented and the other is not, correct? Both
situated on the right side of the seat, as on my CK30?

You can not use your 2nd AUX valve to power a thumb if the 1st one is used to power the hoe, since no fluid gets
to the 2nd one while the first is detented in the ON position.

I never knew that. I've never tried to use the topping lift while the BH was mounted. I cannot imagine why there would be zero flow to the second valve though. Interesting. Does this only happen while the hoe is actively in use or for the duration as long as the first aux is in the on position for the BH? Also, I wonder if my DK40 might be plumbed a bit differently than the CK I suppose.

 

[IslandTractor]

I hope someone gets a quotation. It should be way less than the usual 2-solenoid spool-type diverter/
selector sold by the likes of WRLong. That's the type that requires the purchase of a manifold, too. The
HydraForce unit is a monoblock that does not.

$140 each. Not too bad. Takes a few weeks to get.

I don't quite understand the six port configuration and operation but that certainly is quite a bit less expensive than the WR Long diverter valve. Not sure what the relative benefits/pros/cons are of this valve vs the more standard diverter valve set up though. I have a diverter valve from WR Long that runs my grapple from the FEL circuit.

 

[avc8130]

I never knew that. I've never tried to use the topping lift while the BH was mounted. I cannot imagine why there would be zero flow to the second valve though. Interesting. Does this only happen while the hoe is actively in use or for the duration as long as the first aux is in the on position for the BH? Also, I wonder if my DK40 might be plumbed a bit differently than the CK I suppose.

If you detent the first valve open, all of the flow is flowing through the backhoe. You MIGHT get some flow at the 2nd valve if the restriction is less than the first circuit.

You could also probably swap the valve order in the stack and make it work.

ac

 

[IslandTractor]

If you detent the first valve open, all of the flow is flowing through the backhoe. You MIGHT get some flow at the 2nd valve if the restriction is less than the first circuit. You could also probably swap the valve order in the stack and make it work. ac

I can understand that if I am actively digging there might be no flow left for the thumb but if my hands are off the BH controls, shouldn't there be flow to the second valve/remote??

 

[avc8130]

I can understand that if I am actively digging there might be no flow left for the thumb but if my hands are off the BH controls, shouldn't there be flow to the second valve/remote??

I don't think so. You have diverted that flow to the hoses on the valve rather than through the power beyond within the valve.

At least that is my interpretation.

You could test this if you have a cylinder you can hook up while you have the backhoe connected.

ac

 

[dfkrug]

If you detent the first valve open, all of the flow is flowing through the backhoe.
You MIGHT get some flow at the 2nd valve if the restriction is less than the first circuit.

Yes, all flow from the first valve goes thru its work ports to the hoe, regardless of the position of the hoe's
valves. The hoe is also an open center (tandem center) valve.

The return flow from the hoe is back thru the 2nd of the 2 work ports on the AUX valve, which goes to the
tank from its Out port. No flow goes from the 1st AUX valve thru the internal Power Beyond passage to the
2nd AUX valve. Therefore the 2nd AUX valve is non-op as long as the 1st AUX is detented ON.

I don't know what your 2nd sentence means, AC.

 

[dfkrug]

$140 each. Not too bad. Takes a few weeks to get.

Not bad at all. Did you use the MFGR quotation request form on the HydraForce website? If so,
you then have to go to a disti to sell/ship it to you. Maybe adds $35-50.

I see no downside to using this valve over the manifold-mounted valves. It is SOOOOO much less, too.

 

[kennyd]

$140 each. Not too bad. Takes a few weeks to get.

I don't quite understand the six port configuration and operation but that certainly is quite a bit less expensive than the WR Long diverter valve. Not sure what the relative benefits/pros/cons are of this valve vs the more standard diverter valve set up though. I have a diverter valve from WR Long that runs my grapple from the FEL circuit.

IT, did you clarify if that price included the valve body itself? I think it may be just for the cartridge and solenoid possibly?

 

[dfkrug]

Also, I wonder if my DK40 might be plumbed a bit differently than the CK I suppose.

That is why I asked. Kioti has moved toward using detented AUX valves to power their hoes. They used to have
manual diverters, but that's another topic.

Anyway, powering the hoe this way works, but is not ideal. The usual way is to insert the hoe valve stack in the
Power Beyond daisy chain of valves on the tractor. Usually that means after the FEL valve and after
the AUX valve. The hoe valve "never" has PB, so it should be the last in such a daisy chain, draining into the tank.

I have already modified my detented work-port hoe configuation by connecting the hoe return hose to the tank
instead of the B work port on the AUX valve. That relieves some back pressure and fluid heating.

 

[dfkrug]

I think it may be just for the cartridge and solenoid possibly?

I am sure that is a complete valve. I would have guessed about $150, about 3-4x what
the SV08s are above.

You should try one of these, Kenny, cuz you have familiarity with the D03 valves, and have done
installs in the past. You can provide some pro/con info with experience. I have never bought
the manifold valves before, myself.

 

[kennyd]

I am sure that is a complete valve. I would have guessed about $150, about 3-4x what
the SV08s are above.

You should try one of these, Kenny, cuz you have familiarity with the D03 valves, and have done
installs in the past. You can provide some pro/con info with experience. I have never bought
the manifold valves before, myself.

D, I have no personal experience with DO3's since they are so bulky and most of my work is geared towards smaller machines. I am a proponent of using diverters most of the time especially for grapples and such as I believe they offer a cleaner install, and the PB lines on JD tractors are not as accessible as they are on other machines. When I helped design the diverter I sell, small and easy to mount was top priority.

This little valve is intriguing, but for most applications you would need to switch both lines for complete control, and that one does not do that from what I can see.

 

[avc8130]

Yes, all flow from the first valve goes thru its work ports to the hoe, regardless of the position of the hoe's
valves. The hoe is also an open center (tandem center) valve.

The return flow from the hoe is back thru the 2nd of the 2 work ports on the AUX valve, which goes to the
tank from its Out port. No flow goes from the 1st AUX valve thru the internal Power Beyond passage to the
2nd AUX valve. Therefore the 2nd AUX valve is non-op as long as the 1st AUX is detented ON.

I don't know what your 2nd sentence means, AC.

It means I'm punished to another hour of staring at the hydraulic circuit diagram. Haha

Ac

 

[bindian]

You can not use your 2nd AUX valve to power a thumb if the 1st one is used to power the hoe, since no fluid gets
to the 2nd one while the first is detented in the ON position.

Yep, learned that years ago after getting my BH. Can you put the BH on #2 aux and the thumb on #1? I know you can do that on a Mahindra 4110, as a friend does this.
hugs, Brandi