Custom hydraulic backhoe thumb

[bumperm]

Wetmoose,

Well, it's true that the valve will act as a check valve stopping flow in one direction when off and allowing flow in the opposite direction above a certain cracking pressure. That's not important for this application, though. You are simply using the valve as an on-off switch, to allow to extend or retract the ram to move the thumb when the valve is energized. When not energized the valve will keep the ram at whatever position it is in.

 

[cic317]

Wetmoose,

Well, it's true that the valve will act as a check valve stopping flow in one direction when off and allowing flow in the opposite direction above a certain cracking pressure. That's not important for this application, though. You are simply using the valve as an on-off switch, to allow to extend or retract the ram to move the thumb when the valve is energized. When not energized the valve will keep the ram at whatever position it is in.

perfect, as far as rating on the valve necessary to bump up to the SV10, or does the SV8 have enough cushion to handle the additional flow?

 

[bumperm]

Flow should not be an issue, remember when the valve is activated and the thumb and bucket are moving, flow is split between the bucket and thumb cylinders. When one meets resistance, even gravity, then the cylinder with the least resistance will get more flow. In practice it works just fine - you quickly get used to pre-positioning the thumb where you want it by touching the bucket to ground or object to increase resistance.

When plucking you big tap root weeds, like sage brush, you put the bucket on the far side, the thumb on the near side, push down, squeeze!! and pull up. Weed and roots yank out clean. Pretty darn amazing!

 

[Aquamoose]

I have a new SV8 valve with ORB ports to sell. I've decided to take a mechanical approach by fabricating a foot switch to open/close the valve rather than the electrical solenoid route if anyone's interested.

It comes complete with

- Valve SV08-24-0-N-0-0 (normally closed 4.5 gpm)
- 6306012 connector body
- 7151010 #8 body, #6 ORB 5k psi rated

 

[dfkrug]

I think I might be better with the Hydraforce SV10 VS SV8, any opinions?
Next questions has anyone done anything about pressure relief valves? I have to get time to read
the entire post but I didn't remember seeing anything there.

Your industrial tractor does have more flow than CUTs like mine, so I can see bumping up a size.
But don't forget that your flow is intermittant, and shared with thumb and bkt cyl if you follow
my design.

As for a pressure RV in the work lines, I did mention that, but it is also discussed in some other threads.
It bears repeating: I designed everything to work with my system pressure, so I did not need an
RV. This is not going to be the case if you do not follow my design. I made my cyls the same size,
and my system pressure was only 2500psi. Those with industrial machines need to be careful, as you
may have pressures north of 3000psi to deal with.

 

[Ron50]

Aquamoose. I finally finished my hydraulic thumb conversion. I added another stablizer valve betwween the two stablizer valves. Part description: SDS100/7/Q-101-8L, Working section "Q" style w/o Rings Cyl. Spool Spring Center. Price was $224.37 from Hydraulic Controls Inc. Phoenix, Az.
The cylinder I used was from Bailey Hydraulics. 2" Bore x 10" stroke x 1.25 rod. This folds back the thumb to the right place without hitting the cylinder. SKU #207384. This cylinder allows you to rotate the ports 90 degrees from each other which helped with the install. Price was $175.00.
I also installed a double relief valve under the controls stack on the side to be on the safe side. Boltonhooks.com price $100.
The mechanical thumb just didn't work for me. I'm probably into this beween $650 and $700 when fittings and hoses are added in. You have to trim the sheet metal cover a bit to acomodate the wider valve stack and drill new mounting holes 3/4" wider on each side of existing holes. You also have to get 1 1/2" longer bolts to hold the stack together because of the valve you add in the middle being 1 1/2" thick.
All and all I think it was worth it, it is just like an excavator now. This was done on an Ansung BH65 which is one of the brands Branson uses for their backhoes.
If I ever figure out the picture loading on my Samsung Note Pro I'll load some for you.

 

[dfkrug]

All and all I think it was worth it, it is just like an excavator now.

Congratulations. I would like to see the pix. How do you control it?

The last excavator I operated had a factory hyd thumb. To close it, you pushed
a foot pedal, and it closed all the way. When you released it, it opened all the
way. It used some sort of electro-hydraulic control.

 

[Ron50]

Excavators have electric solenoid operated valves. To operate this backhoe thumb I installed a valve just like the stabilizer valves between the two stabilizer valves. I t makes the stack one valve longer, 1 1/2", which requires three new bolts to hold them all together and some sheet metal modification. It is just one more open center valve in the stack. I installed a handle that is two inches taller than the stabilizer handles right in the middle of all the handles. It is easy to operate with either hand and it is always available. No diverter solenoids, just another valve.

 

[Aquamoose]

Hey Ron50, cool! I'd be interested in your pics when you have the chance. Since then, I've decided to go with a mechanical on-off valve to avoid the 12vdc wiring so I plan to rig some type of mechanical valve for the foot but my options are always open.

 

[Ron50]

Here's a few pictures . Maybe.

 

[Aquamoose]

Wow! Did have to cut the panels to make them fit and drill new holes to keep the valves centered?

 

[Ron50]

Yes it did require using a cut off wheel on small Makita grinder and drilling four new mountng holes to keep things centered. Hardest part was working with Walvoil to get the correct valve. So many choices when it comes to hydraulics. Hydraulic Controls in Phoenix was a big help in ordering the correct valve. I used the same cylinder that Bumperm suggested. I first thought about doing this a year ago. Just now finished it up.

 

[Aquamoose]

Amazing work. Did you get the chance to operate it? What tractor do you have? What's the last picture of? I see rear remotes, on both sides?

 

[downsizingnow48]

Very slick!

 

[dfkrug]

I installed a handle that is two inches taller than the stabilizer handles right in the
middle of all the handles.

As I pointed out early in this thread, adding another spool valve to the stack is one of several
approaches to adding the valve for an hyd thumb. Glad someone has done it.

How it is controlled (hand lever, foot pedal, joystick button, or console switch) is important
and different approaches will appeal differently to different users.

One thing you get with an added stack valve is parallel inlet flow, so you can operate the
bkt and thumb cyl simultaneously and the combo behaves like a grapple.

Costs are substantially higher with this approach, however, and you still have 2 long hoses
that need to be routed up the outside of the boom and dipper.

 

[Ron50]

I've picked up a few big landscape rocks and it worked like it should. I have a Branson 4020R that I bought in 2012 to clear land in Oregon. I got the backhoe for it about a year and a half ago to build retaining walls and excavate for a detached garage. "Still working on getting a permit for that"!
The last picture shows the rear remotes which must be different than yours. I bought one single on the right, new with the tractor. Then I decided to add top and tilt. Easy, I'll just move the single to the left side and add a new double valve on the right for the top and tilt. Wait, as long as I am moving the single to the left side where the mounting holes can accept either a single or double valve I might as well make it into a double valve. I ordered the parts to add another valve to my existing single to make it a double as well. Sort of like a snowball rolling down a hill, I just hope that I have reached the bottom. You could connect the two valves with solid lines if you are good. I chose to use flexible lines because it was easier for me. The valves and mounting plate are how Branson did rear remotes in 2012.
The backhoe is plugged in on the left side in the last picture. I just hold the lever open with a bungee cord when useing the backhoe. This seems to have no affect on the use of the loader when the rear remote is open. Because loader and backhoe are both Ansung they are made to fit together. The subrame of the backhoe attaches to a solid round tube of the loader subframe in front, and to the lower three point hitch arm brackets on the axels in the rear.
Removing backhoe only requires pulling two pins in front, supporting on stablizers, unplug hydraulics and drive away. Takes as long to put three point hich assembly back on as it does to remove backhoe. I have since built a dolley to unload it on which actually makes it easier to reattach.

 

[Aquamoose]

Awesome Ron!

Glad it's working out for you. I'm going to try a foot pedal setup. Routing the hoses to the cylinder is going to be easy so I have no concerns there.

Mine's a 2015 3520h and I ordered dual rear remotes and a front 3rd function. Like you, I built a dolly for my BH in a way that fits under my pallet rack at 37" wide. (grin)

All I need is to get a ripper for the BH so I can put it to good use. With the hydraulic thumb, it'd be very versatile working with the stumps and rocks!

 

[Ron50]

I found the seat to be a little tight so I added more legroom. I added a piece if 3" x 5" steet tube beween the mount on the seat and the mount on the bh frame. This moved the seat 3" toward the tractor which made it more comfortable for me. Just saying in case someone else might be interested.

 

[Aquamoose]

This is an old thread, but I have a newer tractor, and one with a mechanical thumb on a BH77. Giving Dave credit, I shamelessly copied his idea on paralleling the curl cylinder. Works great! (thanks Dave). Here's some pictures and notes:



I used this 2 X 20 cylinder as it has adjustable port positions which I thought good in this app. Shopping



Close up of Hydraforce solenoid valve. Had to special order from one of their distributors - they wouldn't sell direct. I had to use two fittings to attach it to cylinder as the SAE 8 to 6 90* was out of stock - When I get it, I'll remount and also install a bracket for the valve - it is probably sturdy enough if you don't bonk it.





Taken before wiring Solenoid.



I wanted the waterproof push button switch on the joystick. Switch from Amazon, aluminum bracket from my little machine shop.



Finished switch install, shrink wrap on joystick shaft to keep it clean.



I used a Powerlet jack and plug (also referred to as Bosch or BMW plugs - and may be still sold by JD dealers) to plug into the tractor's 12VDC. One neat "happy" was that Kubota, on the B50 series, supplies a wired plug end at the left rear of the tractor AND the plug is a match for the Powerlet waterproof outlet - - how cool is that?!

http://www.powerlet.com/shop-by-product/plugs-sockets-wire-more/PWRDIST



One little "oops" occurred at the rod end of the cylinder. I needed about .360 more width, so made two .180" spacers. However, once installed, the ram end didn't end up on the pin centered - - took both spacers on one side (shown) to fit up nicely - guess this is due to a slight misalignment on the dipper stick bracket from the factory.

There was probably enough slack between the 25mm pins and the 1 inch cylinder end holes so the ram would have centered, but I used .012" brass shim stock to make bushings which took most all the slop out.

Tested it picking up a big rock - works great! And no more having to get off the tractor to deploy or put away the thumb.

bumper

Any chance of pictures? I really want to do my BH76 (Branson) and I already found the perfect cylinder for it.

 

[dfkrug]

Any chance of pictures?

It has been almost 10y since I started this thread, and the pix I posted are still there.

Picasa and Photobucket, and other free posting services are dangerous places to entrust your
photos, as we can see above. TBN still has all the ones I have posted on the site, and I am well over 1000.