PTO Shaft mod from an older snow blower. trying to get shear protection in place.

[pjb153]

So I have a unique issue concerning a 3 PT blower I have purchased. Let me try to explain and see if anyone has other options that may help.

In a Craigslist ad, I spotted a really nice looking heavy 3pt 60 blower so I made the trip and after looking at it.. decided it was coming home. I own a 2010 JD 2305. Smaller machine, but will do just fine with this blower.

I have an issue with no protection in the driveline from the tractor PTO to the Blower input shaft, the PTO shaft is a 35n (heavy boy) that has no shear or slip clutch.

After researching, I found out that the blower is a 60 used on the front of an Allis Chalmers 5020 tractor running off a 540 PTO and was modified to a 3 PT set up.

The input shaft has what seems to be a 1 ｽ round shaft with a keyway. There is a hole drilled through the shaft, but no retaining ring to put a shear yoke on and trust it to stay on. The last thing I want is a bolt to shear on the blower and have a 540 RPM shaft to come loose and kill someone.

The kicker is the 35n series shaft and yokes, I was not able to find a torque limiter (shear pin) to fit on the yoke. The ones I found were for lighter 6n, 12n?

So I am down to what seems to be 4 possible solutions without getting a shop to start welding things..

#1 Try to find a 1 1/2 smooth bore to 6 spline PTO adapter, mount that on the blower and buy a normal snow blower shaft with shear yoke at the machine.

#2 Try to find some sort of female 6 spline with male 6 spline shear clutch to mount at the machine. Plug and play then.

#3 Try to fit up a new drive tube (square shaft) to replace the 35n series drive end with a standard yoke. Then I can purchase a shear yoke with quick connect for at the machine.

#4 Cut my square inner shaft and weld on a new yoke that is a standard light to medium use and gives me a shear yoke option.

Does anyone else see a solution?

Here are some photos for reference.


Thanks in advance

 

[Halftrack]

Typically, I would expect to see a shear bolt on the blower rotor, either parallel to the drive shaft between 2 tabs or perpendicular through the rotor. This would protect the impeller. The auger should be protected with a shear bolt near the large driven sprocket. I would not expect to see any protection prior to the gearbox. Your 4th photo of the input shaft and yoke, depicts an Allen set screw which tightens against the key in the keyway to fasten the yoke to the shaft. If the 2 forms of protection (auger and impeller) are present, go blow some snow. Anybody disagree???

 

[pjb153]

There is a shear on the auger shaft, just prior to the chain drive. That is located all the way to the far left if looking at the blower from the machine seat.

The gear box appears to be sealed and bolted tight. There appears to be no easy way to change a shear if one did exist in there. The impeller has one single bolt in the center holding it on to the gear box. I can't see how that could be a shear.

I will get more detailed photos tonight of all the different pieces.

 

[Halftrack]

After checking some parts diagrams, I see your problem a little clearer now. I agree with you that you need some protection between the tractor and impeller and you have none now. When the blower was converted, the driveshaft needed to be longer and the 35n series fit the job, but the shear protection in the original shaft was lost. I would start with the machinery junk yards, which usually have a pile of pto shafts somewhere and hope to get lucky. Next stop would be a drive shaft shop and take your full pto shaft with you to explain what you want. They usually have pile of used shafts too. Check Weasler.com for their driveshaft componets, maybe you can make something work from them. Other than the junkyard, all the other options look $$$$, been there, done that, more than once.

 

[pjb153]

Here are some more photos of the impeller and the shear bolt on the auger shaft. No protection in place and hence the PTO shaft issue I have now.

I am off work tomorrow and will visit some local shops that may be able to piece together a drive end shaft with shear that will fit into my blower end tube, keeping the blower as is.

I have a feeling some welding will get done before this project is over with.

Another task is lubing those gearbox gears.. I think the easiest is a spray lube and just shoot it behond the guards.

 

[Dutch445]

did you get a dimension of that input shaft going into the gearbox?
larger than 1"?

 

[aczlan]

If the input shaft is 1 3/8", there are slip clutches (such as Slip Clutch Pto, Pto Parts | Agri Supply, 32323, Pto Slip Clutch ) that will bolt right in.

Aaron Z

 

[pjb153]

So update.. I had the day off on Friday and I spent a couple hours running to 4 different local shops in search for a shear plate yoke. Nobody had one, not even on a new complete shaft set-up.

So I bought the Eurocardan 4-LC4 shear yoke with flange from Agrisupply.com. It has the 1 3/8 x 6 spline with quick connect that will go on my tractor PTO, I then will buy a weld yoke #4 and new u-joint from tractor supply locally and weld in my 1 3/16 shaft. A bit of a pain, but worth the protection.

So on to the next step, welding on brackets for my Deere iMatch. Here is the machine and blower all lined up with the set position of where I want things. I have 1/2" steel and a piece of 1/4" angle to weld and support pins on either side for the bottom hooks of the iMatch.

Here are some photos.

 

[RoyBrooks]

Watching this with interest, I have the same make of blower with the same issue. would like to see the end product and hear who it works. I think they are made for Kubota by Mckee or Mackee.

 

[doxford jim]

Just a thought regarding the shear bolt protection. Why don't you use a ful size bolt as per hole, but grind or file a groove on the shaft of the bolt. This will reduce the effective diameter allowing the bolt to fail earlier than it would otherwise do. In effect, it now becomes the "weak link" and will failas you want it to.
There is a shear bolt on the auger drive shaft at the chain sprocket - the single bolt going through the two small flanges. It looks to be bigger than it should be to me - perhaps the hole has been redrilled to a larger size to allow a bigger bolt to be used (say 5/16" instead of 1/4" dia).
I don't mean to derail the thread, but I see you have a three blade fan with what looks to be large radial clearances. If you use the blower at 540rpm, the output may not be the best. If you can, try closing the gap to make a more efficient fan. Using say 3/8" old conveyor belt to make tips, would probably work well. I used 1/4 MS plate to close up the gaps on my three bladed blower. I cheat a bit and also use 720rpm and the blower can really sling the snow a good distance.
Have attached a couple of foto's for you to look at.
Cheers
Jim

 

[pmsmechanic]

I can understand your concern but with 18 PTO horsepower and that size of a PTO shaft I don't think you need any protection. The engine will stall long before anything breaks. Just my opinion. Don't take me wrong on this I'm just saying that I don't think you don't have anything to worry about.

 

[RoyBrooks]

I can understand your concern but with 18 PTO horsepower and that size of a PTO shaft I don't think you need any protection. The engine will stall long before anything breaks. Just my opinion. Don't take me wrong on this I'm just saying that I don't think you don't have anything to worry about.

I have the 48" model of this blower and have had the input shaft shear pin go on a number of occasions. Its not fun trying to get the tractor stopped before the shaft does some damage. It might be because of the 3 blade fan allowing more snow to be pushed in to each blade, that it puts more stress on the 5/16 bolt? but you can hear each blade as it picks up the snow.

 

[doxford jim]

I have had the shear pin fail on my larger 73" blower driven by the 55PTO HP Jinma ( running at 720 rpm instead of 540 rpm) and all that happened was the input shaft to the blower stopped turning.

I doubt that the 18hp will cause much damage and stopping the tractor engines immediately, would be the first thing to do.

Caution is very commendable and necessary, but an over active imagination not so good.

Of course the flailing of the PTO shaft is not good, but the chances of the shaft disconnecting completely are pretty remote - but anything can happen I guess.

Jim

 

[pmsmechanic]

I stand corrected and I don't mind. I bought a used John Deere model 59. It came without the short PTO shaft in front. John Deere always seems to want ridiculous money for those kind of parts so I'm having a PTO shaft made for a little more than half the price at the dealer and yes it's getting a sheer bolt. The problems of users on this forum on their lack of sheer bolt protection encouraged me to do it. I'll post a picture once I have the drive shaft.

 

[RoyBrooks]

I broke another shear bolt on the blower, to keep the shaft from coming off again I ground a slot in the input shaft to the gearbox. I then added a small ground down 3/8" bolt to ride in the groove. The hope is that it will keep the pto shaft on the gearbox input shaft if or when the shear bolt breaks again

 

[doxford jim]

I like what you are trying to do. I am surprised that the PTO shaft came off of the blower - I know in the case of my blower it has never come off the shaft - when the shear pin fails, the tractor PTO output shaft keeps turning and all power to the blower stops.

What sort of angle does your universal shaft sit at when using the snow blower - that might have something to do with problem. I have learned as I have gone along and don't profess to know that much, but I do know that the shaft angle affects the loading of the two universal joint and thus, the end result.

If you get the shear pin arrangement sorted out, I would take a good look at the two universal joints. Are they loose at all - they look to be well used in the photograph and could be original. If I was using your blower, I would worry about those failing at some time in the future. The replacement parts are cheap and should give you more peace of mind if replaced.