U-joint, CV-joint, Thompson coupling

[brian eiland]

Here is a real interesting new development in connecting two power shafts together.
Have a look at this website, and be sure to watch the video

http://cvcoupling.com/index.php?opti...tpage&Itemid=1

...in case that link gives a problem
http://cvcoupling.com/

[Guillermo]

Interesting. Thanks Brian.

[FAST FRED]

TECH Fallout is getting faster and faster , but if you think boat stuff is expensive , wait till you purchase from the Helicopter folks parts bin!,

Still waiting for boats to use a common power bus (ring) and electric for simple controls to operate hyd power packs , done on fighters for decades.

Imagine a windlass or bow thruster with no service time limits , and the no blown fuses of hyd power!

FF

[SeaJay]

I want one!

[mjbtx]

Cool stuff. Need some to replace my merc cv couplings.

[Landlubber]

Thanks Brian, it is unbelievable.

[Frosty]

Well I tried to down load the movie but 1: hour 45minutes was just too much. It looks like a normal UJ in a frame???

[Landlubber]

That is the brilliant simplicity of this Frosty, it really is just a double version, but the second ring makes it all work. It truely is a CV joint.
Most good inventions are simple.
I am simple, but can only try to be good.
Where did I go wrong, I can nod my head up and down move it left and right and even pivot it at the same time, but not in CV.....
Maybe this conversation should be in the drivel thread eh

[brian eiland]

This retractable prop drive might make good use of this new coupling hardware
http://www.amartech.nl/products/retractable-propulsion

[DCockey]

Originally Posted by brian eiland

This retractable prop drive might make good use of this new coupling hardware
http://www.amartech.nl/products/retractable-propulsion

Why would the Thompson joint be better than any of the multitude of other CV joints currently available?

Does the amartech RPS even need a CV joint? Based on the illustration in their website it appears to me that the shaft is only turning with the unit deployed and the angle change of the shaft in the swivel joint is small enough that a simple Carden joint would be sufficient.

[brian eiland]

Originally Posted by DCockey

Why would the Thompson joint be better than any of the multitude of other CV joints currently available?

Does the amartech RPS even need a CV joint? Based on the illustration in their website it appears to me that the shaft is only turning with the unit deployed and the angle change of the shaft in the swivel joint is small enough that a simple Carden joint would be sufficient.

You might recall that in a propeller application the prop is transmitting a very appreciable thrust load up the shaft (axial load to the joint). Most CV's and Carden joints don't like high axial loading.

[DCockey]

Originally Posted by brian eiland

You might recall that in a propeller application the prop is transmitting a very appreciable thrust load up the shaft (axial load to the joint). Most CV's and Carden joints don't like high axial loading.

The Thompson joint is similar to a nested double Cardan joint. No reason it would be any happier with axial loading than a Cardan joint. Corvettes for many years used the half-shafts with Cardan joints on the ends as the upper lateral control links for the rear suspension and those joints saw axial loads. Also some CV joints are designed for axial loads.

No reason a propeller shaft has to transmit thrust to a U-joint. A thrust bearing can be used between the propeller and the U-joint.

Looking at the drawing of the Amartech RPS system on their website (click on the illustration and then click on the arrows for the third slide) it appears that it uses a thrust bearing at the end of the propeller shaft in the swivel joint housing.

Several firms produce propeller shaft systems which use a seal and thrust bearing in the stern post, with an intermediated shaft which Cardan joints at either end between the thrust bearing and the engine/reverse gear. Advantages include allowing soft mounting of the engine for reduced vibration. I'd consider it proven technology for boats in the small and medium size range.

[Petros]

that is a great invention, would make u-joints and cv joints obsolete. looks costly to manufacture however, too many detail parts, so not likely we will ever get to see them on mass produced cars.

[mydauphin]

I am still looking for an inexpensive thrust bearing, the CV joints aren't the problem.

[brian eiland]

Originally Posted by DCockey

The Thompson joint is similar to a nested double Cardan joint. No reason it would be any happier with axial loading than a Cardan joint. Corvettes for many years used the half-shafts with Cardan joints on the ends as the upper lateral control links for the rear suspension and those joints saw axial loads. Also some CV joints are designed for axial loads.

I'm not saying that Cardan joints don't accept axial loads, but when you are directing pushing maybe 200-400 hp thru them to push your vessel, i don't believe they would hold up for long

No reason a propeller shaft has to transmit thrust to a U-joint. A thrust bearing can be used between the propeller and the U-joint.

Looking at the drawing of the Amartech RPS system on their website (click on the illustration and then click on the arrows for the third slide) it appears that it uses a thrust bearing at the end of the propeller shaft in the swivel joint housing.

Here is that dwg. I'm not so sure you could place the trust bearing in the rotating member and have it do its job properly. I suspect the trust bearing is after the 'pivotable joint' where the shaft enters the hull??

Several firms produce propeller shaft systems which use a seal and thrust bearing in the stern post, with an intermediated shaft which Cardan joints at either end between the thrust bearing and the engine/reverse gear. Advantages include allowing soft mounting of the engine for reduced vibration. I'd consider it proven technology for boats in the small and medium size range.

Understood. One must also consider extracting the prop shaft for servicing, particularly in the case of bending the shaft upon striking an object