U joints in phase on PTOs

[Charlesaf3]

I just saw something on the safety list that brought this up. I had no idea that universal joints had to be kept in phase on ptos. Going have to double check mine now - wouldn't be shocked to find I've misphased one, though now I understand why the shafts I have only connect one way.

Not sure if this is general knowledge, so I thought I'd throw it out there. And now I know what today's nugget of learning from TBN is...

 

[Hooked_on_HP]

I had been taught that ujoints had to be in phase also. However in the last few years heavy truck manufacturers have started installing drive shafts slightly out of phase to eliminate harmonics at certain rpm's. I dont agree with this thinking it causes premature ujoint, wear but thats what they are doing.
Bill

 

[Duffster]

I just saw something on the safety list that brought this up. I had no idea that universal joints had to be kept in phase on ptos. Going have to double check mine now - wouldn't be shocked to find I've misphased one, though now I understand why the shafts I have only connect one way.

Not sure if this is general knowledge, so I thought I'd throw it out there. And now I know what today's nugget of learning from TBN is...

What do you mean by "in phase"?

 

[Willl]

What do you mean

Really ?

 

[pat32rf]

It means that if the cross bearings at the front of the shaft are in the horizontal position, then the bearings at the other end of the shaft must be in the vertical, or 90deg to each other. You should not have the bearings at opposite ends of the shaft vertical, (or horizontal ) at the same time.
The problems with having them the wrong way increase with rpm and set up stresses and vibrations that you don't need

 

[RickB]

It means that if the cross bearings at the front of the shaft are in the horizontal position, then the bearings at the other end of the shaft must be in the vertical, or 90deg to each other. You should not have the bearings at opposite ends of the shaft vertical, (or horizontal ) at the same time.
The problems with having them the wrong way increase with rpm and set up stresses and vibrations that you don't need

Wonderful description of a shaft that is OUT OF PHASE.
Here is one correct description.
In phase means the tractor and implement attaching yokes are oriented so the cross bearing ears are in the same plane. And the cross bearing ears of the yokes on the telescoping halves of the shaft are in the same plane when the halves are fitted together.

 

[irvingj]

Ditto RickB- that's my understanding as well: cross bearing ears lined up...

 

[pat32rf]

I always thought that is was backwards as well, then I would look at one that had been made up for me by a small shop about 25 yrs ago,( been giving trouble ever since). This was before we had the web to double check.....Should ask for my money back!!!@

 

[Charlesaf3]

I always thought that is was backwards as well, then I would look at one that had been made up for me by a small shop about 25 yrs ago,( been giving trouble ever since). This was before we had the web to double check.....Should ask for my money back!!!@

hey, you learned something too isn't this a great site?