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Seeking examples of Duplex/Lever Escapements

aucaj

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Hello,

I am gathering information on Duplex/Lever combination escapements. Please, if you own or are aware of any examples, please post them. These particular escapements are briefly mentioned by Paul Chamberlain in "It's About Time". I have attached a photo of Chamberlain's figure 14 from my 1971 copy of his book (I hope it is okay to post it).

I am fortunate enough to own Chamberlain's example from his collection. However, I do wish to post photos because I intend to publish an article, which is why I am requesting assistance with gathering photos of other examples. I recently saw an example sold and I'm awaiting permission to post the photos. Neither Chamberlain's or this other example are signed. Charles E Jacot patented a Duplex/Lever escapement under US patent 4664 in 1846, but no known examples of this design exists. I am curious whether this particular design illustrated by Chamberlain is a Jacot experiment?


Any helpful information or examples would be greatly appreciated.

Kind Regards,
Chris

pg_132_fig14_Chamberlain.jpg
 
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Andy Dervan

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Chris,

Edward A. Locke was a entrepreneur; he sought inventors or patents for establishing profitable businesses.

Herman J. Eisen was issued 2 US duplex escapement patents in March 6, 1894 515861 and 515862 that he assigned to Locke. Locke formed Columbia Watch Co. in Waltham, MA in 1896 to manufacture 0 size lady's watches using Eisen's duplex escapement patents. The company manufactured these watches until 1900 and sold them under Columbia Watch Co., Atlas Watch Co., and Cambridge Watch Co.

This is all documented in my article in NAWCC Watch and Clock Bulletin published in February 2011.

Andy Dervan
 

Allan C. Purcell

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Chris, have you read "Saunier´s treatise on Modern Horology" pages 297 to 345. "The Duplex Escapement" There is a very good copy published from French to English in 1952. Plus his chapter on the lever escapement that follows??

Allan.
 
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aucaj

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It may help to see an example.
Here is a link to the photos of the recently sold piece. I have not heard yet heard back from the seller to get permission to post them directly. And I'm not sure how long this link will remain active.

www.ebay.com/itm/324774087326

Please have a look and post if you know of other examples.


Thank you,
Chris
 

Tom McIntyre

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Tom McIntyre

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The watch in question does not look much like the patent. It appears to have two trains that may be selected to run by the slide in the band.

In the Jacot American duplex lever, a lever watch is designed to have a duplex jewel on the balance which locks the train with the pointed end of the lever resting on the duplex jewel and gives impulse when the duplex slot releases the leaver and receives impulse with the same lever. On the return swing of the balance, the lever just passes over the notch since it cannot be released in that direction.

It acts like a duplex watch, but loses all the mecahnical advantage of the duplex and likely never would have worked.

The four Maltese Cross index mechanism in the subject watch must lock and relase the two trains. I cannot see anything to suggest how that is done.
 

Allan C. Purcell

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If it was you, Chris, that bought the watch? I would say well done. It appears to be a type of chronograph for people who travelled long distances. Plus the Duplex. All you need now is who made it and when. Looks to me like Swiss work?

Best wishes, and good luck,

Allan.
 

John Matthews

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I believe the escapement of the ebay item was 'invented' by Jean Renaud It is credited as such to an item in an Antiquorum auction (Geneva, Hotel Des Bergues, Oct 15, 1994 LOT 31). The auction description would imply a somewhat earlier date than the description given in the attachment.

Anchor duplex escapement 001.jpg

John
 
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aucaj

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The four Maltese Cross index mechanism in the subject watch must lock and relase the two trains. I cannot see anything to suggest how that is done.
Hi Tom,

I thought the same thing until I saw one in person. The Maltese cross is actually just a fancy decorative counterbalance on the end of the lever.

R/
Chris
 

aucaj

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If it was you, Chris, that bought the watch? I would say well done. It appears to be a type of chronograph for people who travelled long distances. Plus the Duplex. All you need now is who made it and when. Looks to me like Swiss work?

Best wishes, and good luck,

Allan.
Hi Allan,

No, I bought Paul Chamberlain's example of this escapement (see attached catalog entry). Ironically, 3 days later this one showed up. I did bid but the winner wanted it more than me.

I had thought it might be by Jacot, but it is close to John's recent post of a Jean Renaud design. The watches are signed, but are there other indicators for Jacot or Jean Renaud? Where do I look for them?

R/
Chris

569_record.jpg
 

John Matthews

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Chris the diagram I posted is from Reinhard Meis - Pocket Watches. I have not looked for a patent.

I couldn't see from the ebay photographs whether the escape had vertical pins.

I assume your example is as the PC diagram you posted. I have seen a number of diagrams of this type of escapement and they all (apart from the PC example) have vertical pins that strike the projecting finger on the staff roller. In the PC diagram the escape wheel tooth strikes a projection from the balance wheel (not a roller) - is that what you have & can you post a photograph?

John
 

aucaj

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Chris the diagram I posted is from Reinhard Meis - Pocket Watches. I have not looked for a patent.

I couldn't see from the ebay photographs whether the escape had vertical pins.

I assume your example is as the PC diagram you posted. I have seen a number of diagrams of this type of escapement and they all (apart from the PC example) have vertical pins that strike the projecting finger on the staff roller. In the PC diagram the escape wheel tooth strikes a projection from the balance wheel (not a roller) - is that what you have & can you post a photograph?

John
John,

I have attached a cropped photo of the crab-claw escapement wheel. Yes, this wheel strikes a projection on the balance (similar to the diagram you posted with the exception of the vertical teeth). Please forgive me for not posting a comprehensive set of photos. I want to possibly reveal the complete design in a published NAWCC article.

R/
Chris

escapement_wheel.JPG
 
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Allan C. Purcell

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This may help Chris.

Allan.
 

John Matthews

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I want to possibly reveal the complete design in a published NAWCC article.
Chris - I look forward to the 'reveal' in article, particularly how the escape wheel strikes the projection on the balance.

John
 
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Tom McIntyre

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John,

I have attached a cropped photo of the crab-claw escapement wheel. Yes, this wheel strikes a projection on the balance (similar to the diagram you posted with the exception of the vertical teeth). Please forgive me for not posting a comprehensive set of photos. I want to possibly reveal the complete design in a published NAWCC article.

R/
Chris

View attachment 675551
The watch you have seems to be No. 88 from the Chamberlain collection. He describes the action pretty well.

The action of a standard duplex escapement or of the Jacot star duplex is very clean and straight forward. Even the so called Chinese duplex is a rather simple design. If you read Jacot's patents, the purpose of the toothed resting arm in the chinese duplex form was to get as fast a beat as possible for the balance while retaining the second's indication on the dial. He describes them with 3 or 4 suplemental teeth to get more beats per second which he believed improved timekeeping by averaging errors over more beats.

Since the duplex only impulses in one direction and each tooth adds two more beats, three teeth will beat 6 times/second and 4 will beat 8 times/second. I think his thoughts also appear in more modern high beat watches with lever escapementsand high frequency balances.

The lever duplex seems a bit wong headed to me. The mechanical advantage of the duplex comes from the long impulse arm receiving the maximum force from the escape wheel's upright tooth, operating at a small radius from the source of energy, and the long locking tooth acting with greatly reduced force at the long radius. If the balance is correctly poised the impulse arm on the balance should not disturb the action unduly.

The lever duplex adds another rapidly moving mobile element and impulses the rim of the balance, which seems mechanically unsound (although Leroy's original chronometer escapement had the same behavior.)

Will you be able to measure the energy distribution in the example of the movement?
 

aucaj

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Will you be able to measure the energy distribution in the example of the movement?
Tom,

I appreciate the response. Certainly, I could do some kinematic analysis and even a CAD model. But I think that data is only meaningful in comparison to other duplex designs. It is also important to take into consideration the age and condition of movements before drawing any conclusions. I think those efforts would only serve to confirm what we already can infer from rarity of this design. I have seen only 4 of these in my years of collecting. If this particular design held any advantages over others, it would probably have been more prevalent in the market place.

While it has been described by Chamberlain, there are no existing photographs of this piece. As it said, a photograph is worth a thousand words. I have been devoting some of time to tracking down as many of the items from Chamberlain's second collection. I hope to produce a document showcasing some these more interesting pieces that were unfortunately not photographed in his earlier publications. For that matter, the photographs in his book and the 1921 exhibition catalog are poor quality. I think it would be interesting to see better quality photographs of those too.

R/
Chris
 

Tom McIntyre

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It’s not much of a picture, but this is in the 1921 catalog.

8A015410-CEF7-49BC-97EA-A5FF1B4AF776.jpeg D9B83737-3A9C-4660-90E6-FB24E62D8341.jpeg
 
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aucaj

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Number 88 is from his 1st collection and is owned by the MSU museum. I have number 569, which is from his second and much larger collection. It is a different from 88. I have attached the entry.

569_record.jpg
 

John Matthews

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Chris - when you responded to Tom I was in the process of posting this ...

It seems to me that the movement that Chris has acquired is not the same as lot 88. The photograph that Chris posted clearly shows that the escape cock is beneath the balance. This is not the situation with the movement sold as lot 88.

I do have one question. As the escape cock is beneath the balance wheel can you please confirm that the escape wheel tooth strikes a projection from the balance wheel (as in the Chamberlain diagram). I just cannot see how this is possible as the balance passes over the escape wheel cock which is obviously above the escape wheel (as viewed from the back of the movement as in the photograph). In other words I cannot see how the Chamberlain diagram applies to your movement, but the Jean Renaud design where the impulse is provided by the escape teeth acting on a roller mounted impulse dart could.

John
 

Tom McIntyre

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Number 88 is from his 1st collection and is owned by the MSU museum. I have number 569, which is from his second and much larger collection. It is a different from 88. I have attached the entry.

View attachment 677161
I am not familiar with a catalog of the second collection. I just reread the Fortunat Mueller-Maerki review of the 2009 publication, but he makes no mention of a catalog of the second collection which he estimates at 1,500 items.

He does mention that Margaret Chamberlain disposed of the second collection. I am familiar with some of the items from the second collection such as the Raingo Orrery Clock that was on display in Columbia until a week or so ago.

I know there was rumored to be a dispute with Mrs. Chamberlain over some of the items that were on study loan to Chamberlain at the time of his death. In particular, I was told by the McIntyre family that Fred McIntyre had lent some artifacts of the McIntyre Watch Co, to Chamberlain, which she refused to return, claiming that Chamberlain had purchased them.

Are there copies available of the catalog to the second collection?
 
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Allan C. Purcell

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The, 2009 NAWCC National Convention Exhibit- Grand Rapids Michigan. I don´t think would help you much Chris, though it must be said the photographs are much better than the previous issues of Chamberlains collections. (See below) Most of the photographs just show the outer case, front and back- in the main the movements are not shown. A quick count of 47 watches in here, so a very small percentage of the second collection.

Allan.

66-63.JPG 66-64.JPG 66-65.JPG

PS: Sorry Tom, found the Fortunat Mueller-Maerki revue at the back of the book, after the above.

66-66.JPG 66-68.JPG 66-67.JPG
 
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Tom McIntyre

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Allan, The 2009 booklet and exhibit were from MSU and would not have included any items from the second collection. At the moment, the contents of the second collection are a mystery except for those items Margaret chamberlain is recorded as having sold. I think all of her sales from the collection were private sales, so in the absence of this inventory of the second collecttion, its contents are largely unknown.

We can probably pick out items from It's About Time that do not show up in the 1921 AIC catalog.

Ralph's insurance listing of the items displayed at Elgin is another shot of the second collection, I think.
 

aucaj

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I do have one question. As the escape cock is beneath the balance wheel can you please confirm that the escape wheel tooth strikes a projection from the balance wheel (as in the Chamberlain diagram). I just cannot see how this is possible as the balance passes over the escape wheel cock which is obviously above the escape wheel (as viewed from the back of the movement as in the photograph). In other words I cannot see how the Chamberlain diagram applies to your movement, but the Jean Renaud design where the impulse is provided by the escape teeth acting on a roller mounted impulse dart could.

John
Hi John,
While I was waiting for the watch to arrive, I read Chamberlain's description multiple times. I visualized some kind of arm coming down from the balance wheel. It is actually a projection from the balance shaft in the same plane as the escape wheel.


R/
Chris
 
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Tom McIntyre

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That is the geometry of the standard duplex impulse arm. When the locking tooth leaves the locking stone the impulse tooth strikes the impulse arm.
 

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