self-winding watch;
centre-seconds watch;
wrist-watch
- Museum number
- 1988,0409.7
- Description
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STAINLESS STEEL CASED SELF-WINDING CLUB-TOOTH LEVER WRIST-WATCH WITH BLACK LEATHER STRAP.
Wrist-watch.
Movement with club-tooth lever escapement and rotary automatic winding.
Silver-painted metal dial with Arabic hour numerals.
Black painted-metal hour and minute hands; silver and red-painted centre-seconds hand.
Square stainless-steel case with two-piece snap-on button and stainless-steel back retained by two screwed-on bars.
Black leather wrist-strap.
- Production date
- 1957-1963
- Dimensions
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Diameter: 22.20 millimetres (dial (square))
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Diameter: 26.50 millimetres (square)
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Length: 225 millimetres (strap)
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Thickness: 11.80 millimetres
- $Inscriptions
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- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
ETERNA WATCH COMPANY
Switzerland, c. 1950.
Self winding wrist watch with a club tooth lever escapement.
Signature: On the dial ETERNA-MATIC SWISS MADE and five dots representing the balls in the self winding weight ball race. On the movement 'ETERNA.MATIC BREV.DEP.'
Case: A square stainless steel two part case, the back secured by four screws, one of these is missing. When these screws are removed there are two latches that have to be moved out so that the back can be separated from the front. The stem then has to be separated from the button, the two being snapped together, possibly the first use of this technique. On the outside of the back is the number 3435849, on the inside is the following 'BREVET' and the Helvetia cross 'ETERNA WATCH Co. SWISS ACIER INOXYDABLE'
Also the number 3429905.
Dial & Hands: A matt silvered dial with a square chapter ring with black Arabic numerals and minute ring. The back of the dial stamped with a circle with within a trade mark resembling two W's linked by a stroke between them at the top. The hands are skeletonised and are painted black, the centre seconds hand is silvered with a red tip.
Movement:
Ebauche Marks: 1199R, beneath the balance.
Frame: A nickel silver movement finished by spotting. A bridge for the balance and keyless work and another for the train. Cocks for the lower pivot of the centre wheel, the pallets and the balance.
Barrel and Mainspring: A recessed cover to the going barrel.
Barrel: internal diameter 6.7 mm., height 1.25 mm.
Mainspring: height 1.25 mm., thickness 0.08 mm.
Barrel Arbor: diameter 2.2 mm., snailed.
Hooking: A slipping mainspring.
Train: All the wheels gilded, the centre wheel, third and fourth wheels with five crossings. The steel escape wheel with four.
Jewelling: Jewelled bearings from the third wheel onwards, all the jewels pressed in. Endstones to the lower third and escape wheel pivots. Incabloc shock protected bearings to the balance.
Escapement: A straight line layout club tooth lever escapement with short lever, double roller and D-shaped impulse pin. The exposed pallet stones have flat acting faces. A steel escape wheel with four crossings.
An equidistant locking escapement.
No. of teeth embraced 3½.
Balance & Spring: a monometallic balance with brass screws. Balance diameter 7.35 mm., thickness 0.65 mm. A 'self compensating' flat spiral spring with 10 3/4 turns.
Means of Regulation: A tailess index on the balance cock registers against three stokes with '+' and '-' engraved on the balance cock table.
Train Counts and Beat Rate:
Great wheel 72 (barrel)
Centre wheel 70 pinion 10
Third wheel 66 pinion 7
Fourth wheel 77 pinion 11
Escape wheel 15 pinion 7
An unusual train.
Beat rate 18,000
Motion work: cannon pinion 10
minute wheel 24, minute pinion 8,
hour wheel 40
Winding System: Conventional positive wound keyless work.
Self Winding Work: The self winding work may be removed in its entirety by releasing three screws. This reveals a conventional movement. The reduction from weight to barrel is through gears. The weight 'A' pivots on a ball race a cross section is shown in fig 0-0. the balls are 'a'
In fig 0-0 the weight carries a steel wheel which meshes with both wheels E and D Between E and D is a steel disc which carries two sets of clicks one pair on each side. These clicks are arranged so that the tail of one acts on the head of the other and have the same action as if the pair were a normal single click and spring. The two wheels E and D are recessed to receive these clicks and have internal teeth which act with them. A pinion is fixed to the disc and always turns in the same direction whichever way the weight turns. Two further wheels and pinions are in the self winding train - the last pinion winds the barrel ratchet wheel direct.
Dimensions:
Case: 26.4 mm., wide 28.9 mm., height 11.1 mm., over the glass.
Movement: diameter 22.1 mm., height 7.3 mm.
Provenance: Purchased in 1988 with the aid of funds from the Dingwall Bequest.
Exhibited: One of these watches was shown at the British Horological Institute Exhibition 'The Modern Watch' held at the Goldsmith's Hall, November 1st, 2nd and 3rd November 1949.
Literature: See D. de Carle 'A Two Way Winding Automatic Watch' HJ September 1949 pp. 543 and 544.
- Location
- Not on display
- Condition
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Latest: 2 (2017) not seen inside
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2 (Jun 1995)
- Acquisition date
- 1988
- Department
- Britain, Europe and Prehistory
- Registration number
- 1988,0409.7