Arps 730 backhoe on Kama KM554

B

BradBlazer

New member
I bought this backhoe used about 14 months ago and finally finished the subframe for it. Here is a video from right after I bought it trying out the hydraulics with it hooked up to the 3-point. It's pretty easy to see why I want a subframe mount.



Before making the subframe I replaced 1 bad valve section and added hydraulic stabilizers.
 
I wanted a quick-attach feature that would not interfere with the 3-point. This is what I came up with. The idea is for the rail part on the left to be permanently attached to the tractor (one on each side) with the adapter on the right attached to the backhoe. Back the tractor up, raise the backhoe to engage the hooks and the pin holes self-align. The pins are 1" OD cat2 top link pins.



Here is the photo sequence of making the quick attach ends. It was all scrap metal I had collected. The main part of the rails for under the tractor are 2x4x1/4" tubing. I welded a 2x2" tube under that and expanded it further to 2x8" right at the connection joint. A short piece of 2x8x1/4" tube on each side will be the base of backhoe adapter.


 
Fitting to the tractor. I carved some brackets out of 8x6x1/2" angle iron to attach the rails to the rear axle.


I measured the diameter of the loader tube (5.555" on the "band mic") and cut the front end off the other rail to make the weld-on bracket. I also cut an 8" piece of 3x5x1/2" angle iron for the mating piece on the rail.
 
I used the portable band saw and grinder to notch the 2x4 tube to the match the loader tower tube and clamped them in place to get the position figured out. I used a transfer punch to mark the holes. I think two 180,000psi 1/2" shcs should be plenty.




The plan was to get everything where I wanted it and tack all of the brackets, then take it apart and make the welds in the shop. I even took off the loader tower.
 
Here is the adapter. It was too rainy to use real paint so I used the rattle-can black fast-drying Wal-Mart paint.

That strange pocket in the top link support bar is where I cut off the 2x8" tubing you can see. (used steel, what can I say?)




Here it is ready to mount to the backhoe. The lower tabs drew out due to the three-pass welds I made. I used a length of all-thread to pull them together enough to slip them into the capture slots on the BH. All 3 connections are double pinned. Thank goodness this isn't where I am connecting every time.



The Guide Tabs were interfering with the lower link nuts so I had to trim them.
 
Some assembled pictures:



The rear wheels are just off the ground. The non-pivoting feet dug in and prevented lifting any higher.


As a test I did extend the boom and let it jerk a little with the stabilizers up and the connection seems rock solid. No noise out of the connection. The tractor just bounces a little on it's tires.
 
As an added safety, I added a drawbar support. I used a holesaw to make the pin hole in a piece of 1x3 solid bar. The little holes were already there. They did give the shavings a place to go while sawing.


I cut a little off so it could be inserted with the hoe in place and welded on a hook . The angle of the hook is to help retain the chain.

It inserts easily through a pocket I welded to the bottom of the adapter and into the drawbar receiver. It should provide some extra support to the backhoe adapter.
 
It got dark on me but I played around with it a little. I had a bunch of old plastic mulch that had been dumped in the ditch that I wanted to get rid of so I dug a big hole and buried it. Being wet and dirty it would have been a huge chore if I took it to the "convenience site." It's not in the pics but I was able to easily push the trash and backfill into the hole with the loader with the weight of the hoe as ballast. So far the work flow using the rear remotes on the stabilizers is fine. I can back up to where I want to dig, put the outriggers down, put the loader down, then climb onto the backhoe. On the softer ground the stabilizers can slide and pick the tractor right up.

The ARPS 730 has a 24" bucket and 9.5' dig depth.

 
Awesome work Brad. Sorry I missed it first time around.
Dang, I have hoe envy. :D
Reps for you for great project pics. :thumb:
 
BradBlazer,:wave:
Looks like you have a nice finished project.:cool: I think, however, that the subframe pins should have been further apart. I reference this to the fact my Bradco 511's upper and lower pins are 18 inches apart. Extreme digging directly aft should be fine, but digging full left or full right may apply too much torque on the subframe. I hope not.:respect:
hugs, Brandi
 
Brandi,
Sorry I didn't check back until now.

Thanks for the concern (and the hugs)
That Bradco is pretty similar in size to my unit:
http://www.swdistributing.com/purple/b4.html I don't have the full specs for mine - still waiting for the free manual promised by Ameriquip.

I did a shear calculation on the pins based on boom straight back and boom cylinder at relief pressure, neglecting any help from the stabilizers, mating surfaces, or hooked pins.The safety factor was about 3x with mild steel pins. When working to the side, the forces should be transferred more directly to the stabilizers plus the distance between pins in the plane of action is greater (Straight back in-line is the minimum spacing). Let me know if I'm missing something.

I was originally thinking about taller adapters but I couldn't come up with anything elegant that didn't interfere with the 3-pt, etc.

Thanks,
Brad
 
BradBlazer said:
Brandi,
Sorry I didn't check back until now.

Thanks for the concern (and the hugs)
That Bradco is pretty similar in size to my unit:
http://www.swdistributing.com/purple/b4.html I don't have the full specs for mine - still waiting for the free manual promised by Ameriquip.

I did a shear calculation on the pins based on boom straight back and boom cylinder at relief pressure, neglecting any help from the stabilizers, mating surfaces, or hooked pins.The safety factor was about 3x with mild steel pins. When working to the side, the forces should be transferred more directly to the stabilizers plus the distance between pins in the plane of action is greater (Straight back in-line is the minimum spacing). Let me know if I'm missing something.

I was originally thinking about taller adapters but I couldn't come up with anything elegant that didn't interfere with the 3-pt, etc.

Thanks,
Brad
Click to expand...
Brad,
I am an aircraft mechanic. I specialize in sheetmetal structural repair. I don't have any formal engineer schooling, but mechanics tend to do the hands on engineering. I might be wrong here, but I will use a helicopter to get to my point. A helicopter's engine powers the rotors with torque to fly. Torque has an evil brother that has to be overcome or the helicopter will rotate (torque in the opposite direction). Now suppose your tractor is the helicopter and the stabilizer is the tail rotor and the backhoe digging 90 degrees is torque. Basically this concetrates all stress at the subframe mount you made short vertically to clear your 3PH arms. Is this clear? It might take a while, but I think stress cracks will appear at some point in time if you dig aggressively alot (like I do) from 90 degrees.

hugs, Brandi
 
Hi Brandi,
No BIG projects yet although I do have some more trenching and clearing planned. I did trench about 50 feet for an RV connection and did some ditch clearing. The backhoe works well. I took it off the tractor last month* and that went well too. The fit of the pins didn't seem to change at all.

*I needed to hook up my fence stretcher to do some cross-fencing to separate my young buck goats.

Thanks for asking,
Brad
 
BradBlazer said:
Hi Brandi,
No BIG projects yet although I do have some more trenching and clearing planned. I did trench about 50 feet for an RV connection and did some ditch clearing. The backhoe works well. I took it off the tractor last month* and that went well too. The fit of the pins didn't seem to change at all.

*I needed to hook up my fence stretcher to do some cross-fencing to separate my young buck goats.

Thanks for asking,
Brad
Click to expand...
Brad,
Is your fence stretcher home made or store bought? How about a photo or two of it?:nopics:
hugs, Brandi
 
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