source for PTO shafts with wide angle CV U-Joints

[Mosey]

Anybody know of a source for a PTO shaft with CV U-Joints. After reading this article:

http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/eng9924

It appears I can achieve an overall 90 degree angle with a PTO shaft that has a CV U-Joint at each end. I have no idea where to find them and how much they cost though.

 

[beenthere]

Maybe I am missing something here, but the Cardan joint (didn't know that was what it was called, until I read that article) is located in two places on a common PTO shaft. The combination of the two seem to equal the flexibility of the single CV joint.

So I don't see the advantage of the CV, and replacing the cheaper Cardan joints isn't a big problem, nor something that happens very often. They do make a lot of noise when the total angle approaches 90° (45° at each joint).

I wonder if two CV joints would allow 180° operation?

 

[Mosey]

My understanding of the article is that a single Cardan joint can be angled 15 degrees and one at each end allows a total angle of 30 degrees. A single CV joint can be angled 80 degrees and one at each end allows a total of 160 degrees. I'm looking for something to achieve a total of 90 degrees so a single CV joint won't quite do it, but a PTO shaft with a CV joint at each end should do. Maybe I'm way off on this. I admit a single CV joint allowing a 80 degree bend seems unbelievable.

 

[ZJ_HR]

CV joint is used usually when you have implement which must be run all the time, and can't be disconnected at big steering angles, like a baler for example, which will turn even when power is cut.
As you can see on enclosed pic, CV is used for run corn picker, and is not disconnected at each end of field. I'm steering up to angle when PTO shaft hit a tractor tyre, aprox 80-85 degrees. Need to remember that this angle is not for a long time, and not for full load.
Second place where I'm using PTO shaft with CV joint is manure spreader (trailor). It is very convinient, as we have two stage clutch on smaller tractor, and you don't need to stop at each end of field.

My conclusion: use CV (double cross cardan joint) for trailed implements, when you need sharp turning with them running.

 

[Mosey]

ZJ_HR, Thanks for the info. Don't post that picture in the Safety forum though! What happened to the PTO shaft shield?

 

[ZJ_HR]

Previous owner doesn't care about shields. Time when pic was taken was just after buying this machine, and it was not enough time to repair all things. Usually we take care about danger.I repaired this shaft for next season, but just can't cover CV joint, due to vibration and noise problem.
I'll make a pics pto shafts what we have /forums/images/graemlins/wink.gif
Rest of my attachments have standard PTO shafts (all protected).
BTW, what can you say about safety of this machine (who cares about borrowed, bare, PTO shaft) ??? /forums/images/graemlins/grin.gif

 

[frederic]

U-joints generally shouldn't be "bent" past 10-15 degrees, as the more bend it has, the more stress it must endure. This is why driveshafts in rear wheel drive cars and trucks typically hover around 5 degrees - they're after survivability and reduced vibrations.

CV joints are more interesting... for a given size they are less strong as compared to an equal sized u-joint made of normal materials, however don't rule them out because of that.

Audi, Porsche, Nissan, Caddy et al use CV's in their 800HP mid-engined Sports Car Prototypes so they can be strong.

A good source for inexpensive CV's are to leech the front axles off any 4WD S-10, pickup or blazer, from 88 through 95 just before the body style changed. They had very strong axles with CV's on both ends, and you can hack the shaft in half and weld in an extension. I've done that a few times in racing applications with excellent results.

Typically the S10 front half-shafts are unloved, and dirt cheap. No one seems to realize they have the same strength as the Eldorado front half-shafts, which are the ones everyone desires and willing to pay a premium for.

 

[ZJ_HR]

Danny,
Here are pics what I promissed.
Set of our PTO shafts:
-on top: Bondioli&Pavesi - for corn picker
-up: Walterscheid, with CV joint added at home - for manure spreader
-down: Walterscheid, with friction clutch - for Vicon pendulum spreader
-bottom: local brand - for sprayer and hay rake

 

[ZJ_HR]

Close look to CV joints, at max angle. Dangerous is bend over that angles, as cross can jump out of central sliding plate.

 

[beenthere]

Here is one I found.
landrover

Also, looking in McMaster-Carr, found universal joints with bearings that claim 45° operating angle for each joint.

Quote "" These oversized U-joints have the highest torque rating of any needle-bearing U-joint. Lube fittings are included for easy lubrication. U-joints connect to shafts via set screws (included) and standard ANSI keyways (included; see page 1039 for ANSI keyway dimensions). Maximum operating angle is 45° ; maximum rpm is 2500.
Standard U-joints have a maximum torque of 10,000 in.-lbs. Made of forged steel with cast ductile iron yokes. Overall length is 5". Heavy duty U-joints have a maximum torque of 22,000 in.-lbs. Made of forged steel. Overall length is 5 1/2".""