Horological Meandering

Famous last words:
"The difference between a tourbillon and a karrusel resides in the speed,with which, the cage rotates and the position of the balance. When the cage makes one revolution per minute and the balance is mounted coaxially with the cage -  it is a tourbillon. Anything else is a karrusel." :  Some-Horology-Author-Somewhere, I'm sure

 

 

 

Karrusel movement.......but not by Bonniksen

 

 Apparently, Bonniksen invented his 'karrusel' in 1892, bypassing Breguet's patent for a fixed wheel and using a differential effect instead, to rotate the cage. There was no difference between Bonniksen's and Breguet's movements for timekeeping, so people only remember the earlier tourbillon.

If only someone would make a watch with a karrusel escapement, whose balance is mounted in the centre of a cage, which makes one revolution per minute.........

Would that karrusel be a "tourbillon" too, by definition?

Would it be better than a tourbillon, from a design/aesthetic viewpoint?  (since no one has proven timekeeping is any better)

You academic horology fans out there - Discuss.....

 

MTF

This message has been edited by MTF on 2007-10-24 13:03:01

. . . as I recall past threads on the subject-

Carriage speed doesn't define a tourbillon per se, IIRC (i.e. there are 12 second tourbillons et cetera).  Tourbillon is defined by the presence of an escapement and balance rotating around a fixed fourth wheel which may or may not be co-axial with the balance; if not, also IIRC the preferred term is "carousel-tourbillon" which is NOT a karrusel.

Karrusel tourbillon is a different animal; the term properly (again, IIRC- aw heck this whole thing is IIRC) refers to Bahn Bonniksen's variation on Breguet's basic concept.  In a Bonniksen karrusel the third wheel pinion turns a platform on which the escape wheel, balance, and lever are mounted- in this it's like the tourbillon but in a karrusel the fourth wheel is not fixed, it turns at the usual speed and carries the seconds hand (whereas in a tradition tourbillon of whatever type, the carriage rotates inside a fixed fourth wheel.

Daniels says that the karrusel works just as well for averaging poise errors (in a pocket watch, which is the context for his discussion) and they did very well in observatory time trials as did finely finished pocket tourbillons.

They generally are considered to be easier to construct and just plain less interesting to look at which is probably true- the platform on which the balance, lever and 'scape wheel sit turns pretty slowly and it just doesn't have the drama of a tourbillon.  Plus my guess is due to the thickness created by sticking the 'scape wheel, balance, and and lever on a platform that actually carries the balance cock as well and rides above the plane of the rest of the train, it'd make for a pretty thick wristwatch.

All by way of saying that in a wristwatch, it would suffer from all the practical disadvantages of a tourbillon in a wristwatch without any of the visual drama which usually excuses the presence of a tourbillon in a wristwatch.

Personally I happen to like them very much though, at least in a vintage context.  A wonderful, quirky, and in a pocketwatch very succesful contribution to chronometry .

Jack

it is slow, thats why it result in not as appealing as a tourbillion. And some believed that it does not produce as much stress compared to a tourbillion

XY

. . . although again IIRC there were karrusels made with faster rotating platforms. . . I'd have to hit the books .

Jack

do have different rotation time just like Tourbillion. You are right Jack : )

Xian Yang, XY

to talk about things I have no ken aboot...........

So, is THAT definition of 'tourbillon' ...generally acceptable, because that is what they are teaching in the official WOSTEP textbook? ooooo.....I love controversy!

MTF

AFAIK (again this is just from memory of archived threads on Watchrap) the WOSTEP definition specifies a fixed fourth wheel; I don't recall whether or not it also specifies that the balance has to be co-axial with the fourth wheel (though of course that is the 'classic' implementation.)

Also per Dr. Daniels, in a Bonniksen karrusel, the platform turns on a collar concentric with the fourth wheel pivot and this collar is a possible point of significant wear, which of course can bring the whole thing to a stop.  If they're well made and regulated my impression is that both a tourbillon and a karrusel can be excellent timekeepers but you loose power on the way to the escapement in both cases.  The tourbillon has to turn the carriage via the locking and unlocking of the escape wheel which means you need a really light cage so there's less inertia to overcome; the karrusel doesn't have the problem of extra load on the 'scape wheel but the third wheel has to not only turn the fourth wheel, but also haul around the platform with the cock, balance, 'scape wheel and lever on it.  In a pocket watch, with some room to spare and a nice burly mainspring, that's spending most of its time pendant up I can see the point, but in a wristwatch- well, the karrusel especially seems problematic in terms of bulk.

I still like 'em though.  .

The versions of the tourby where the balance is NOT co-axial with the fixed fourth wheel (like the version Calabrese did for BP) are visually engaging but displacing the balance laterally means a smaller diameter balance which IIRC all other things being equal (which they never are) means a bigger challenge to maintain isochronous behavior.

I personally think my deep affection for karrusels is fundamentally irrational.  They generally went into high grade pocket watches, many destined for chronometric competitions, so that plus the muscular dimensions just scratch my horologico-kinesthetic itch .

Jack

www.network54.com

I stand by most of what is contained in that post but am less than optimistic about any grand, clarifying changes in official definitions anytime soon. 

Frankly, the WOSTEP definition is terrible.  It's simply all we have.  Until another disinterested, internationally recognized horological body weighs in, we're stuck with what WOSTEP has to say on the subject I'm afraid.

_john

I'll let the gentlemen discuss the fascinating topic of this thread - but can I jump in and ask what the stunning picture is..??  I've never seen anything like it before and I'm blown away..!!

I really must do some more research on clocks.....even better if there was a clock forum here..??

Yours,

Andy.

That was a sculptural clock by Jean Kazes (AHCI Member) made for Vincent Calabrese, incorporating "tourbillon concept" from a model that Calabrese made to illustrate the controversial definition of 'karrusel' vs 'tourbillon'.

 

Calabrese concept scale model

 

Jean Kazes sculptural 'tourbillon-like' karrusel clock - position 1

Jean Kazes sculptural 'tourbillon-like' karrusel clock - position 2


Regards,

M.T- (Don't shoot the reporter) Foo 

great thread too..!!

Andy.

Bahne Bonniksen's original layout of the karrusell escapement seems to have the balance wheel 'E' in the center of the platform as can be seen from the drawings in the Swiss patent No. 7965 dated 27. January 1894.

From a scientific point of view there is a considerable difference between the tourbillon escapement and the karussell escapement. The scetch below shows three different gear diagrams. Such diagrams are e.g. used to analyse planetary gear topologies for automotive drivetrains, but are good for watch movements as well ;-)

The top one belongs to the standard escapement: Three reduction gear sets are put in a line to change the speed from the minute wheel to the escapement wheel. The escapement wheel is peridocally released by the escapment.

The gear diagram in the middle belongs to a tourbillon escapement: The reduction gear following the intermediate wheel is no longer a simple reduction gear with the cage fixed to the housing of the movement, but a tourbillon with the cage rotating and the output shaft fixed to the housing of the movement (ususallly a fixed second wheel).

The lower gear diagram describes Bahne Bonniksen's karussell escapement. The escapement is fitted to a rotating platform which is driven from the intermediate wheel via a gear set. The characters in the scetch refer to the drawing in Bahne Bonniksen's patent. Please note that this layout cannot be adapted to have the platform running at 1 revolution per minute. As faster the platform spins as slower needs the escapement wheel to run in order to maintain the 1 revolution per minute at the pinion 'A'.  At 1 revolution per minute the escapement wheel would have to run at zero speed which is impossible. From my point of view the advantage of Bahne Bonniksen's invention is the fact that the impact of the friction in the platform bearings on the accuracy of the movement is 52.5 times lower compared to the 1 minute tourbillon. The reflected inertia of the platform is even by the factor of 52.5 times 52.5 smaller than the one of a tourbillon cage. 

I hope I wasn't getting too academic now

Best regards from Germany

Heinrich

Hi Heinrich,

Thanks for that explanation.  I've not seen that notation before, and presenting them in that way helps considerably understanding the differences.

And, no, you weren't being too academic.  More, please!

Gruss

nick

 

. . .never seen that type of gearing diagram before but it makes the power flow through the train and the difference between a Bonniksen karrusel and a conventional tourbillon immediately obvious, I wonder if movement designers ever use such diagrams.

Jack