Chronometry: Is this what the Swiss meant by "Echappement a Ressort"?

Discussion in 'Chronometers' started by Dr. Jon, Feb 24, 2016.

  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  1. Dr. Jon

    Dr. Jon Registered User
    NAWCC Member

    Dec 14, 2001
    5,386
    183
    63
    Aerospace Engineer
    New Hampshire
    Country Flag:
    Region Flag:
    I just bought this detent chronometer.

    cuvette_s.jpg Dial_s.jpg Mvt_full_s.jpg

    Up to now I had believed that "Echappement a Ressort" meant a spring detent chronometer. This is a pivoted detent but the return spring is straight rather than a spiral which I believe is a "bascule". This sprig has the same form as a spring detent but it drives the detent about a pivot.

    Here are two closer views of the detent arrangement.


    Detent_s.jpg

    Here it is with some features called out.

    Detent_arrow.jpg

    The green arrow shows the straight return spring. The red arrow on the lower left points to a peg which position the detent. The other red arrow points to the locking jewel which is a bit hard ot see from this angle.

    The chronometer is running very nicely so I have not yet worked up the nerve to remove the balance to check out the rest.

    The maker is very reputable so I believe the marking is legitimate for the time which i estimate to be early 1860'

    My question is this "Is this what the Swiss meant by "Echappement a Ressort"
     
  2. doug sinclair

    doug sinclair Registered User

    Aug 27, 2000
    14,364
    47
    48
    Calgary, Alberta
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    Google translations tells me the word ressort in French (Swiss) translates as spring. Since the detent escapement is an escapement, it seems the translation would be spring detent (escapement). But I've been wrong, before.
     
  3. Dr. Jon

    Dr. Jon Registered User
    NAWCC Member

    Dec 14, 2001
    5,386
    183
    63
    Aerospace Engineer
    New Hampshire
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    It is matter of usage "ressort" is the word for spring. My association of ressort with spring detent is from the records of the Neuchatel chronometer testing service. They kept book on the performance of various arrangements including spring geometry composition and escapement. They had two categories for detent escapements , bascule and ressort. My thinking was/is that since a bascule is a pivoted detent and there were only two types they meant spring detent by "ressort".
     
  4. Tom McIntyre

    Tom McIntyre Technical Admin
    Staff Member NAWCC Star Fellow NAWCC Ruby Member Sponsor

    Aug 24, 2000
    81,790
    1,292
    176
    Male
    retired SW dev
    Boston
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    If I am viewing ti correctly, the "tail" of the locking lever seems very heavy to me. Also the locking is really close to the balance so the unlocking and impulse will be really close together. I would love to see more pictures when you work up your nerve. ;)
     
  5. Luis Casillas

    Luis Casillas Registered User

    Oct 16, 2012
    570
    9
    0
    Software
    San Francisco Bay Area
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    Some quick Googling seems to support your impression here, but since ressort just means "spring" in regular, non-horological French, I'd conjecture that whoever labeled this watch so simply chose to express it somewhat colloquially.
     
  6. Dr. Jon

    Dr. Jon Registered User
    NAWCC Member

    Dec 14, 2001
    5,386
    183
    63
    Aerospace Engineer
    New Hampshire
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    Horological French is specialized. For example "racquet" is French for regulator although in colloquial French I am sure it is the cognate of racket and it is because a regulator looks somewhat like a tennis racket. The Elsevier DIctionary provide no help here.

    The measurements and classifications were put into place a bit after this watch was made so the terminology may have been more fluid than that it was at the time of the reports.

    To Tom's comment, the lever seems to have more material than needed at the tail but it may be counterpoise. Modern thinking is that lightness is more important but this view is very recent.

    But, has anyone seen one like this?
     
  7. DeweyC

    DeweyC Registered User
    NAWCC Member

    Feb 5, 2007
    1,487
    389
    83
    Watchmaker
    Baltimore
    Country Flag:
    Re: Has anyone seen one like this

    I am going to do something I revile; offer a fact free opinion.

    I can see the locking and unlocking is accomplished by a pivoted lever and the spring is a separate piece. Cute and while my experience is far from exhaustive, I have never seen this execution.

    I wonder if the expectation in the classifications was that there would be "one piece detents" and "two piece detents" with the two piece detent being the pivoted detent with the spiral spring. I would then class with the pivoted detent.

    This guy was out to make waves, that is for sure. I like it a lot.
     
  8. Dr. Jon

    Dr. Jon Registered User
    NAWCC Member

    Dec 14, 2001
    5,386
    183
    63
    Aerospace Engineer
    New Hampshire
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    I found a diagram of this in Saunier's Treatise. It is a form he credits to Bertaud also used by Motel. Saunier criticises this execution for its use a pin which the spring pushes. The issue is that that point requires lubrication and is subject to wear. My copy is old and delicate but if anyone has a modern reprint the diagram is on plate IX figure 10. The pin visible in the screw head is traditionally gold. Saunier classes this as a pivoted detent.

    I have two dictionaries on horological French and neither has any entries on detent escapement types so terminology was not widely fixed.

    Deweys view of th eclassification is the same as mine with the term "Ressort" applied to the one peice variant. The firm "Rossel" was very reputable so I do not believe they meant to deceive with this inscription.
     
  9. Dr. Jon

    Dr. Jon Registered User
    NAWCC Member

    Dec 14, 2001
    5,386
    183
    63
    Aerospace Engineer
    New Hampshire
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    Here are some more pictures. I forgot to wind it the other day and it stopped so with no power in the train I removed the balance.

    Here is the drawing from Saunier from teh Google Books version
    Drawing.jpg The straight line is the return spring.

    Here are the detent and roller Bare_detent_s.jpg Roller_s.jpg
     
  10. Jerry Treiman

    Jerry Treiman Registered User
    NAWCC Member

    Aug 25, 2000
    6,001
    856
    113
    Geologist - California Geological Survey
    Los Angeles, CA
    Country Flag:
    Region Flag:
    Re: Has anyone seen one like this

    Very neat watch and nice research. Thanks, Jon, for sharing it with us.
     

Share This Page