skyeriding
900
Thanks for sharing Rick,
You're correct that there is no distinct mechanical "clutch" (such as a horizontal or vertical clutch), but instead I believe these work via a direct friction coupling (as a "crude" clutch, in a way), something like this in the following image of a Lemania 1341. This one has a central minutes recorder.
When not in operation, a clamp holds down the minutes recorder and it continuously "slips" against the cannon pinion of the running minute hand. The idea is that the minute hand rotates relatively slowly versus say, a seconds hand, so friction is still tolerable at the low speeds.
Similar mechanisms are often used for the hour recorders, such as the Speedmaster Cal 861. In this case, the mainspring barrel arbor itself drives a geared hour recorder, using a friction spring as the slipping clutch. This rotates even slower than the minute recorder above, thus friction should be even more managable.
From www.watchprosite.com
While these are the simplest "clutch" design, the natural downsides to such a design is that it induces higher friction/load to the movement when the chronograph is stopped, especially for the minute recorder of the 1341 above. And of course, eventually when the friction fitting wears out, the recorders become loose and problems may happen. Or more oftenly seen, the brakes may not engage properly and the continuous hour counter will still operate even when the chrono stops...
Similar as to how the 861's hour recorder has gearing above to achieve the proper gear ratios as an hour recorder, I believe the Ebel 139 (I couldn't find any dialside movement photos online!) uses a similar gearing setup but for the minutes instead. Since the central minutes of the Ebel 139 only sweeps at 2/3 the speed of the regular minute hand, it thus requires a 2:3 gear ratio with the slipping coupling to achieve the same effect.
Regards,
skyeriding
The Word From Habring—Repost w/diagrams...
Hello fellow Purists! (And would some kind moderator please take down the original post? Thanks!) Last week I posted some feelings about the movement of the chrono minute hand—specifically my preference for the semi-instantaneous "jump" or some, rather th...
Thank you for such an insightful post,
Its easy to take for granted the features on the watch. Eg "why can't I just have a 60m subdial counter?". It makes sense when you start putting yourself in the watchmaker's shoes, and start imagining the designs for yourself - which in this case, the tho...
Well, you are WAY ahead of me, Skye. You'll be happy to see what I'll be able to put up as an addendum later today as I'm just completing a back 'n forth with Richard
to make sure that I understand this whole business 100%. (As you seem to, already!) More later, then… Fred
Several Lemania movements have continuous chronograph minutes.
Particularly, in my experience, the 1340 and it’s derivatives. For example, the Ebel version with three subdials—their caliber 137—used an indirectly driven minutes counter with continuous motion. Their caliber 139 provides a central minutes counter. But ...
Many thanks for this, Rick. One trick I've stumbled onto (I'm working on a MacbookPro) is to open the photo on the desktop (mine opens automatically in Preview)
and pull down the Tools menu to Resize. Most of my photos are large (for detail) so I cut the size to 1/2, and then before exiting I take a screen shot of the photo (shft/cmnd/4), cropping it however I want (or leaving it as is - as soon as you release th...
Here’s a picture
Of the Ebel 1911 BTR, caliber 139, with continuous central minutes. The minutes counter uses a three-pointed hand moving over a 120-degree dial scale. —Rick ...
Thanks for sharing Rick,
You're correct that there is no distinct mechanical "clutch" (such as a horizontal or vertical clutch), but instead I believe these work via a direct friction coupling (as a "crude" clutch, in a way), something like this in the following image of a Lemani...
It never occurred to me that the minute counter reset hammer was on the dial side.
I’ve studied these movements with a loupe, but not the dial side and not with disassembly. But there is a reset hammer only for the chronograph seconds hand, plus its famous Delrin brake. Thank you for the explanation. —Rick
I could not agree more
The detailed technical discussions aside, what shines thru for me is Richard Habring’s generosity of time and spirit in answering this question. I have a Habring Erwin, and have communicated with Maria before, and the couple’s kindness and friendliness is...
