Pto cement mixer

[6sunset6]

I have a PTO Cement mixer. Got it at Central Tractor 20 years ago for $50, but that's another story. As has been mentioned in various places before the drive shaft length is a real challenge for this application. It is so short you cannot raise it high enough to mix a full load or ( with the same mech conn) lower it far enough to dump. I have managed with 6 80# bags of gravel mix and hoeing it out. When I added Pats connects it moved the mixer 4 inches out. I did not want to buy a new drive shaft so I got a 4 inch extension. It works a little better but the hyd top link is not long enough. It came with a single acting cylinder which may be longer , I have to find it.
Hydraulics .......... wait for it......
A hydraulic motor on the mixer shaft. I have remotes . This would be the cats meow. What size motor? Some req are known
Tractor end 2250 psi , flow 5gpm Probably less at idle
Mixer end 30-60 rpm torque unknown
Mixer infor says it can handle 900 # of cement
Surplus center has a nice motor for $130
3.2 ci, 1750 psi, ( need a cross over relief valve), 730 in-# , 400rpm at 6 gpm
This is 4.6 hp ( looks like 10:1 red on chain drive ) whoops 10 to 1 speed reduction say 7x more torque. hmmm 28hp.
Hmmm ran this mixer with 18hp on the PTO on my old tractor .
Anyway Does anyone think this will work? This is probably an intellectual exercise because I only have to pour 30 80# bags for 5 posts for a machinery shed roof on my barn . but then I have some bridge abutments next year Maybe a winter project.
One more question. IF I run this backwards will it self empty like the big boys do?

 

[J_J]

6sunset6

Using your figures, a 3.2 cu in motor at 1750 psi will develop 892 in lbs, or 74 ft lbs. Should be enough. It is turning on a bearing with a gear ratio. As far as dumping, if the blades are straight, a good tub angle will dump everything, in the fwd direction. If the blades are curved, and you reverse the motor, the angle of the blades will try and push the cement out, but you still have to tilt it somewhat.

I have one of those 1/3 HP electric mixers, and it does a good job.

 

[6sunset6]

JJ Thanks Good to have a sanity check. I found my original single acting cylinder. It may give me just enough to dump . With the drive shaft level it seems to pivot around the same plane so If I don't use the 3 point to raise and lower the PTO shaft stays the same length.
I still would like to put a hydraulic motor on it though.

 

[kennyd]

Check out THIS post from dfkrug...

 

[6sunset6]

oh yeah I saw that forgot. My mixer is in good shape I think I will just mount the motor in line with the existing shaft 1" to 1 " with a flex coupling.
Leave it on the three point I think. No backhoe and with Pats everything is easy to change.

 

[dfkrug]

I think I will just mount the motor in line with the existing shaft 1" to 1 " with a flex coupling.
Leave it on the three point I think.

Got any pix of your mixer, Bob?

Yeah, you can use a Lovejoy-style coupling....that would work. A solid
coupling will work, too.

Going hydraulic (from PTO) has advantages even if you keep the mixer on
the rear 3-pt. The drive shaft for my Mixer80 arrived too long, so I had
to cut it down. Too short would be REALLY bad.

As for reversing the drum rotation and getting the mud to auger out of
the drum, you have to change the flutes inside to get that to work. My
Mixer80 has steel bars to do the mixing....they are mounted inside the
drum with a couple inch gap between them and the inside of the drum. This
design will not work to push the mud out. New flutes that are mounted
to the drum with no gap will be needed to make that work. I may do that
eventually with mine, but I do not know when.

 

[6sunset6]

Here are pictures of mixer and a hyd motor I found on my hyd shelf. I have no idea where I got it and the tag is torn off but I matched and measured and it is a Charlyn H around 8ci displacement 1" shaft It turns by hand and had plugs in the ports. should work well if I ever get to it.

 

[dfkrug]

Here are pictures of mixer and a hyd motor I found on my hyd shelf.

If that has 8ci displacement, you are in the right range, Bob.

Your paddles are similar to mine....they will not push the mud out very well,
in my experience. You have to eliminate that gap between them and the
inside of the drum and extend them closer to the opening. Check out the
readi-mix truck drums. I have mixed tons of stucco (glutinous liquid) as
well as concrete with 0" slump and 1.5" aggregate.

I am from the KISS (keep it simple) philosophy. You don't really need or
want that LoveJoy-style coupler. It is unnecessary and it pushes the
motor out from the mixer quite a ways. I considered mounting my motor
right to the input shaft that the PTO driveshaft uses, but my shaft was
something like 1.375" in diameter and I would have to fab up a support for
the motor. Consider mounting your motor right to the mixer frame as I did.
Remember, this is a very low speed and fairly low torque application.

SurplusCenter has a great selection of sprockets and solid couplers.

 

[6sunset6]

If the coupling is solid and the mixer shaft is in a sleeve bearing and the motor is flange bolted to something then nothing is floating and I think there would be premature wear on one of the bearings. Hopefully the sleeve but probably the bearing in the end of the motor. I think the purpose of the lovejoy joint is to provide flex for slight misalignments. ??????

Never mind I looked at the way you did it. You took out the sleeve bearing for the sprocket shaft. That works.

 

[dfkrug]

I think the purpose of the lovejoy joint is to provide flex for slight misalignments. ??????

Yes, but you are turning very slowly and there is little side load on the
small sprocket. Since it is chain drive, small misalignments can be
tolerated without damage.

I DO use LoveJoys for driving hyd motors at high speed, as with a 3600
RPM engine and direct drive.

Just trying to save you some unnecessary work....