Hydraulic Quick Attach

   / Hydraulic Quick Attach #1  

downsizingnow48

Elite Member
Joined
Jul 29, 2013
Messages
2,749
Location
Sacramento, California
Tractor
Kubota B21
I didn't start out to make a hydraulic quick attach, or even a quick attach. I started to make a grapple. But after taking off the factory 4-pin bucket to make some measurements, I changed the plan. The bucket (212 lbs) was easy enough to put back on, the flat bottom makes it scootable. But the grapple will be about 360 lbs and not very scootable at all. So I started to look at quick attach options.

About that time Blue Power put up a thread on his quick attach similar to the Euro standard and using a linear actuator (http://www.tractorbynet.com/forums/kubota-owning-operating/332587-home-made-quick-attach.html). Then Fallon put up a thread adapting a linear actuator to his factory ssqa (http://www.tractorbynet.com/forums/customization/321704-linear-actuator-power-ssqa.html).

Many thanks to the OPs and the commenters. These threads gave me lots of information to worth with. Two points were particularly important. First, starting the quick attach from scratch, it would be simpler to make a horizontal pin locking mechanism like Blue Power, rather than make two over-center hand operated latches. Second, reading comments by Ovrszd and Roadhunter, I decided to use a small hydraulic cylinder rather than the linear actuator, since I was going to have to put a hydraulic hookup on the loader anyway.

This past week I got started setting up the hydraulics.

Photo 1: A while back I installed auxiliary valves, between the seat and the fender. PB from the loader valve goes to the aux valves, PB from the aux valves goes to the backhoe. The rear valve operates the hydraulic thumb, the front will be for the grapple. Both valves have work port reliefs set at 1200 psi.

Photo 2,3: The hoses going forward fit neatly under the seat and behind the transmission cover.

Photo 4,5,6: The hoses go to a bracket on the ROPS brace next to the loader valve. From there I made three simple brackets to keep the new hoses tidy and close to the loader tubes.

Photo 7: The existing loader tube brackets make a handy place to mount a new bracket using studs instead of the factory cap screws.

Photo 8,9,10: The new bracket is made from 4"x.25" flat bar and 6"x2"x.188" rectangular tubing. It carries and also protects the diverter valve, a set of disconnects for the grapple, and a set of bulkhead fittings for the quick attach cylinder.

In another week or two I will add a section showing the quick attach, which I am still working on.
 

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   / Hydraulic Quick Attach #3  
Nice indeed. Interested in seeing the rest.
 
   / Hydraulic Quick Attach #4  
:thumbsup: Watching with interest.
 
   / Hydraulic Quick Attach #5  
Watching with interest also. Mine will be happening later this spring :)
 
   / Hydraulic Quick Attach
  • Thread Starter
#7  
It took me a couple weeks to come up with a design. It is not built to either the skid steer or the Euro standard, although it is functionally similar to the Euro design. The photo shows the main components. Not much to it. The quick attach works out to 83 lbs calculated weight of metal plus 5 lbs for the cylinder. The two loader bucket adapters are 14 lbs each so total weight for the mechanism is 116 lbs. It could probably be reduced to 100 lbs. The distance between the original bucket pin center line and the with-adapter center line is 4". That is more than I wanted, but the stick-out of the Kubota loader arm nose (1.75") and the height of the bucket ears above the pin holes (.75") are the limiting factors to making the distance smaller.

I have the weekend free to weld it up so will send another update in a few days.
 

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   / Hydraulic Quick Attach #8  
I mean absolutely no disrespect, but with those fabrication skills I must ask why you did such an awesome job only to have a non-standard attachment method? Seems it would have been almost or just as easy to do SSQA and then you'd have all the benefits of a standardized attachment method?

It's looking great so far!
 
   / Hydraulic Quick Attach
  • Thread Starter
#9  
You raise a very pertinent question and I am happy to discuss it.

I studied the SSQA standard closely. It is excellent, and as you say, widely used. I would have liked to use it. The reasons I did not use it have to do with DIY fabrication, and use of the single hydraulic cylinder. First, on fabrication. The SSQA design locks the implement in place with three wedging actions - mating 45 degree lips at the top, mating 120 degree lips at the bottom, and the vertical sliding pins. The holes for the pins are located in the bottom 120 degree lips. Making the 4 matching 45 degree lips, and the 4 matching 120 degree lips, would be a lot of work, without a large metal bending machine. And using a weld-it-together DIY technique, it would be difficult to make strong bottom lips with wide holes for the locking pins. For Shield Arc and some others on this board that maybe wouldn't be a problem, but I know my limitations as a welder.

Second on the cylinder. Using two vertical locking pins as the SSQA does, I would have to use two small 2 inch stroke cylinders, which could certainly be done, but would require the expense and installation of a second cylinder, hoses, etc. Or, I would have to make two crank-arm assemblies, to translate horizontal movement of a single cylinder into vertical movement of two pins. That would be a lot of additional work and also add weight to the mechanism.

The design I am using is a modified Euro quick attach, using a hook-and-pin at the top, and two horizontal locking pins at the bottom, in this instance 1x2 bar moving in 1.5x2.5 rectangular tubing. This arrangement also locks the implement securely in place, but is much easier to make using the tools and skills I have. And is easily adapted to use a single hydraulic cylinder pushing both ways at the same time.

The downside as you say is none of the SSQA (or Euro for that matter) implements can be hooked up. That is very true. But, all I need is a bucket (already have it) and a grapple (making that from scratch).

So from a practical point of view making the quick attach non-standard does not have much downside for me, whereas making the mechanism to the SSQA standard would involve significant difficulty and some cost.

I hope this makes sense. I have made one or two mistakes in my life and this might be another! But that is how I have thought about this.
 
   / Hydraulic Quick Attach #10  
Good, sound logic for your decisions. I'm in the same boat as you regarding the nonstandard design. What I'm planning will work with my existing bucket, pallet forks and grapple which are already set to work with my Kubota QA. Anything else I want, I'm going to build and I'll never be lending anything so matching another design is a moot point.
 
 
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