Strange escapement design? What is this?

[aucaj]

I need some help understanding this escapement design and I would like to know who made it, if possible.

It is a cylinder escapement but there is a crescent-shaped gear that engages the bottom of the balance shaft. Is similar to what you'd see on a rack lever watch. I have heard this called a "pirouette"? Is there an expert that can tell me more about this escapement design?

Also, the movement is missing its blued steel Louis XVI style minute hand. It was 18 mm from center arbor to the tip. Does anyone know where I can find a replacement?

Thank you,
Chris

 

[eri231]

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Like this one ?



regards enrico

 

[aucaj]

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Like this one ?

View attachment 647538

regards enrico

This is similar. However, on my movement the 'pirouette' does not appear to engage the cylinder wheel. It appears to only engage a gear on the bottom of the balance shaft.

 

[Ralph]

Was it in a watch case or possibly a small clock case with simple automata and the gear being complete, instead of a sector? The gear could then drive something externally. Pendulette, rocking ship, etc, ??

Ralph

 

[aucaj]

Ralph,

I hadn't consider that, but it is certainly possible. It does appear to have clear access to that pirouette shaft. Although I can't know for certain. I acquired it as a loose movement.

 

[pmwas]

Or a hacking mechanism of some sort? Having a c/s this could have a hacking feature. To either hacking or some automaton indeed..:

 

[Ralph]

I like the hacking possibility..

Ralph

 

[John Matthews]

Chris

I do not believe this escapement has, and never had, the functionality of what I understand to be a pirouette. Here you don't have a complete gear and as far as I can determine the cylinder is on the balance arbor as normal and not on a separate one. The partial gear is surely engaging with a pinion on the balance shaft. When applied to a cylinder, the engagement is as shown in the diagram posted by Enrico and in operation it allows the balance wheel to rotate more than 360°. In the original escapement (of verge type, see Fig 22, p.150 of Chamberlain) for every impulse from the escapement the balance made several revolutions, first in one and then in the opposite direction.

I appears to me from this photograph



that the gear would be partially visible if you removed the dial as it appears that the pillar plate has been shaped to accommodate the gear. This might provide an insight into its function.

Does the gear look as it has been modified? It is difficult to tell from the photographs, but if it has that might also be a clue.

John

 

[Ralph]

Without a complete gear on the cylinder, the balance assembly would seem to be so out of poise as to be non functional.??

Does the watch run?

Ralph

 

[aucaj]

Thanks for your insights, John. I will get you some photos with the dial removed to help with your evaluation.

 

[aucaj]

Ralph, the watch runs really well and keeps time.

 

[Ralph]

Ralph, the watch runs really well and keeps time.

When horizontal or any position?

Ralph

 

[aucaj]

When horizontal or any position?

Ralph

Ralph: It ticks in all positions without hesitation. I hope that helps.

 

[aucaj]

John:

I've attached some photos with the dial removed. Please let me know what you think. There is a "FEF" in an oval stamped on it as shown in the new photos. I'm not sure if that means anything to you. I made a video of it ticking also, but I can't seem to attach it here.

Regards,
Chris

 

[Ralph]

Sorry, for some reason I thought the sector was mounted on the cylinder. There apparently is a pinion on the cylinder, that drives the sector.. The terminal ends of the sector do not look craftsmanship like. I'll stick with thinking there was a complete gear at one time, for a hack, or driving something external.

IMHO, Ralph

 

[aucaj]

Sorry, for some reason I thought the sector was mounted on the cylinder. There apparently is a pinion on the cylinder, that drives the sector.. The terminal ends of the sector do not look craftsmanship like. I'll stick with thinking there was a complete gear at one time, for a hack, or driving something external.

IMHO, Ralph

Ralph,

Would you mind elaborating a little on what kinds of things would be externally driven? What kinds of automation? What do you mean by hack? I'm just not familiar with some of this? I think I've seen paintings with Windmills being turned?

Thank you,
Chris

 

[roughbarked]

Ralph,

Would you mind elaborating a little on what kinds of things would be externally driven? What kinds of automation? What do you mean by hack? I'm just not familiar with some of this? I think I've seen paintings with Windmills being turned?

Thank you,
Chris

There's no extended pivot. No other indications of how it could have driven any whizzbangs.
Looks more like anti banking device.

 

[Dr. Jon]

I also suspect this is a banking limiter. It has or had stops tp prevent teh balance from swinging too far.

This is consistent with the balance lacking a pin usually on good cylinders to to this and tehmarkignm "Brevet" meaning patent. I suspec this was an example of this patent on a banking limiter.

In this usage banking means swinging too far and having teh escapement tooth come into teh cyliner on the wrong side.

 

[pmwas]

I thought about a banking limiter as well, but the balance wheel already seems to have one...

 

[gmorse]

Hi Chris,

Whatever its purpose, that sector is certainly a poorly finished cut down wheel, probably not original, and the cock for it also looks like a later addition. As it engages with a pinion on the balance staff, (which also has a cock matching the first one in style and finish), its arc of movement must be quite small. The cock at its upper end also looks different and there's no provision there for an extended pivot. The banking, as Paul has noted, is taken care of by a pin in the balance rim so that isn't its function. I can only think that there would have been a lever of some sort attached to the arbor of the sector, which could have driven an automaton oscillating in time with the balance. These could be a blacksmith with a hammer or a woodsman with an axe for example.

Regards,

Graham

 

[John Matthews]

Chris

FEF first



I agree with Ralph it looks as if it was a complete gear and it has been modified. I do not favour neither a banking limiter nor a hack device. It appears to me that at the same time the gear was modified, other elements that were attached to the underside of the pillar plate were removed. There are a number of holes in the pillar plate, the function of which I do not understand. Is it possible that the dial has been replaced? Could the holes have supported a simple mechanism driven by the oscillating gear?

John

 

[Allan C. Purcell]

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This is the article in French, though the photographs could help?? John, I take it you can read French. It's about halfway down.

Allan

 

[aucaj]

I took a closer look under magnification and it does appear to be a cut down wheel of some sort. The dial could be a replacement, but it is a good fit to the movement. I thought it was a odd piece and I am glad to have learned a little more about it. I appreciate all the input from everyone.

 

[roughbarked]

Anyway, it is interesting and we'll probably never know until another example pops up.
There can 't be many left about or there would be evidence of that?
Dr Ranfft hasn't found one yet.
Despite what is said about F.E.F. on mikrolisk regarding 1921.
FEF were making jewelled lever watches in 1920. According to Ranfft.
Presumably this watch was made well before 1920.
I'm no horological historian but something seems somewhat awry about all that.
In truth if it was a novelty watch with a man bashing a seal with a club then somebody probably removed it because it didn't appeal to the owner?
There does appear to be a vertical pin on the balance but these are usually horizontal to the balance in examples I've seen.
There appears to be no reason why the wheel cannot be removed without difference to the watch function in that case. Which of course strengthens the argument that it is there for amusement purposes.

 

[gmorse]

Hi roughbarked,

There appears to be no reason why the wheel cannot be removed without difference to the watch function in that case. Which of course strengthens the argument that it is there for amusement purposes.

Removing it may well improve the running of the watch, without that extra friction and inertia encumbering the balance action.

Regards,

Graham

 

[roughbarked]

Of course.
For "without difference", I should have used "without impairment".

 

[pmwas]

Hi roughbarked,


Removing it may well improve the running of the watch, without that extra friction and inertia encumbering the balance action.

Regards,

Graham

I’d not remove it, though. Someone once made it for a purpose and it’s part if movement’s life story

 

[roughbarked]

Yes. It is a pity that there are parts missing.

 

[SKennedy]

I'd also agree it is there to drive some sort of automata. My general experience of automata is that the makers are more interested in the motion than the delicacy of the mechanism that drives it! I have seen a movement which had a part attached to the lever arbor of the watch movement so it would flick to and fro. This seems to be a different way of achieving that with a cylinder escapement.

 

[roughbarked]

Yes I've seen a number of ones with attachments on the lever arbor. Horrible timekeepers.

 

[John Matthews]

This seems to be a different way of achieving that with a cylinder escapement.

Seth - I think you mean achieving a different type of movement. Would not the movement driven by the balance arbor be different from that driven by a lever arbor?

John

 

[SKennedy]

Seth - I think you mean achieving a different type of movement. Would not the movement driven by the balance arbor be different from that driven by a lever arbor?
John

Well, since it is geared to the balance staff, that quadrant will move to and fro in a relatively small arc of movement, in the same way as the lever in a rack lever escapement. If we guessed that the pinion on the staff has 8 teeth, and the balance has a swing of 180 deg each way, then its only going to use around 4 teeth each side of the centre point on the quadrant. So if there was an arm or something attached to it then its movement would be smoother than the flick back and forth of a detached lever but the angle would probably be similar.

 

[John Matthews]

Seth

It was the nature of the motion, the smoothness, in particular that I was thinking of. From the state of the back plate, it looks to me as if there may have been additional gearing and if so that may have increased the angular rotation that was used in the missing automata.

John