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