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Thompson CV Joint


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#1 jpf

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Posted 01 April 2012 - 05:01

Just wondering if anyone here has heard of these, or knows of their use in the wild.

It is evidently a nesting of two conventional universal joints, with a clever mechanism to keep them in proper relative phase and split the angle equally between the center yoke and the input and output shafts.

Certainly it looks complicated, but it also seems to be a pretty tidy piece of engineering.

Good video from the manufacturer with overview and demonstrations:


Short bit on wiki:
http://en.wikipedia....ompson_coupling

Short interview, some patent materials and drawings follow:
http://www.rexresear...n/thompsnuj.htm

Thoughts? Might it have more inertia than a ball-and-cage? Hard for me to guess.

Seems like it might be worthwhile for offroaders or rally cars, where they have enough suspension travel to warrant the complexity. Williams might like it with their relatively large driveshaft angles from their super low gearbox, too.


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#2 cheapracer

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Posted 01 April 2012 - 05:17

Man knows all about those ...

http://www.pattakon....takonPatDan.htm

#3 Greg Locock

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Posted 01 April 2012 - 05:29

There's proably nothing much wrong with the technicalities but the marketing makes me heave. When they first hit the headlines they were making claims like bignum reduction in losses compared with a double cardan. True enough, but a double cardan is already incredibly efficient, so reducing the losses gives only a tiny performance benefit. Similalry with improved CV performance - a double cardan is already a pretty good CV, improving its performance si not high priority

#4 jpf

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Posted 01 April 2012 - 15:20

Pattakon strikes again! Pretty interesting stuff, especially about the -2/+2 deg wear issue.

Greg, interesting also, thanks. I can easily see how it is unnecessary for things like steering columns or prop shafts, but it seems like there may still be some good applications for it. I'm wondering if it's taking off anywhere.

Edited by jpf, 01 April 2012 - 18:42.


#5 MatsNorway

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Posted 01 April 2012 - 20:08

If it does what it claim it will allways be a nichè marked for it.



#6 Grumbles

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Posted 01 April 2012 - 20:48

I'm aware of the Thompson coupling only because he and I live in the same town and I know one of the engineers involved. I was interested at first, but like Greg I was completely turned off it by the promotional videos. The weaknesses of the existing conventional joints are ridiculously overplayed, and some of the things he was quoted as saying in the local press were clearly false. It may have certain niche applications but I've always thought of it as being a solution in search of a problem.

#7 Powersteer

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Posted 02 April 2012 - 00:03

a solution in search of a problem.

I like that last line...

:cool:

#8 manolis

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Posted 02 April 2012 - 05:57

I'm aware of the Thompson coupling only because he and I live in the same town and I know one of the engineers involved. I was interested at first, but like Greg I was completely turned off it by the promotional videos. The weaknesses of the existing conventional joints are ridiculously overplayed, and some of the things he was quoted as saying in the local press were clearly false. It may have certain niche applications but I've always thought of it as being a solution in search of a problem.


Grumbles,

After filing for a patent, and ten days before publishing anything at http://www.pattakon.com , I emailed to Thompson Coupling about the patCVJ as a solution of the small-angle-reliability-problem of their TCVJ.

I am still waiting for an answer.

If you meet the engineer you mention, please ask him to take a look at the PatCVJ.

Thanks
Manolis Pattakos



#9 JockinSA

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Posted 03 April 2012 - 05:54

I like that last line...

:cool:


I reckon that statement sums it up. it rather looks to me that one is taking a pile driver to open a walnut. The thought of what all that lot would cost to make from a commercial point of view, then put it together and finally throw it in the bin because the boot leaked and got some dirt in it just seems mad to me.