- Museum number
ROLLED-GOLD CASED AUTOMATIC CLUB-TOOTH LEVER CENTRE-SECONDS WRIST-WATCH WITH UP AND DOWN DIAL AND GREY CALF-SKIN STRAP.
Movement with pedometer winding and club-tooth lever escapement.
Painted-metal dial; white chapter-ring with gilt Arabic hour numerals at 3, 6, 9 and 12, with gilt dots for others; below 12 a state of wind aperture.
Gilt-metal hour and minute hands, blued-steel centre-seconds hand.
10ct rolled-gold case with snap-on bezel.
- Production date
Diameter: 34.20 millimetres (case)
Diameter: 29.30 millimetres (dial)
Length: 223 millimetres
Thickness: 12.20 millimetres
- Curator's comments
- Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript)
Made by Le Coultre
Switzerland, c. 1975
Self wound wrist watch with up and down work and a club tooth lever escapement.
Signature: On the dial 'LECOULTRE Automatic', on the barrel bridge 'LECOULTRE SWISS 17 SEVENTEEN JEWELS UNADJUSTED 481' (the number in a rectangle), on the weight 'AUTOMATIC', on the balance cock 'VXN' this latter an import mark.
Case: A two piece gold filled case with, on the outside of the back '10K GOLDFILLED D & A'. Inside the back is 'CASED AND TIMED IN U.S.A. BY LECOULTRE' and the number 308930. The case with a grey strap with gilt buckle and marked 'K KREISLER GUENUINE CALF SKIN 11/16 R'.
Dial & Hands: A silvered dial with a white chapter ring, gilt Arabic numerals for the numerals 12, 3, 6 and 9, and with dots for the other hours. An aperture for the up-and-down indication below 12 o'clock with the up-and-down dial showing through. A black minute circle. The centre seconds hand painted black, the hour and minute hands gilt.
Movement: A nickel plated brass movement.
Ebauche Marks: Under the balance the number 481.
Frame: An extended front plate over which the weight runs. A bridge covers the keyless work the barrel and the train. A cock for the pallets and one for the balance. The bridge carries another bridge for the wight arbor and the fine ratchet wheel. On the inside of the front plate is the number 734474. A subsidiary bridge under the main bridge carries the lower pivot of the centre wheel and supports the centre seconds wheel
Barrel and Mainspring:
Going Barrel: I diameter 8.9 mm., height 1.2 mm.
Mainspring: height 1.10 mm., thickness 0.0925 mm.
Barrel Arbor: diameter 2.65 mm., not snailed.
Hooking: The slipping attachment has a length of 32 mm., and is 0.16 mm. thick.
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. Additionally jewels for the weight arbor bearings and a lower jewel for the pivot of the fine ratchet wheel. Ruby endstones to the balance jewels, these mounted flexibly for shock protection.
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.
A equidistant locking escapement.
No. of teeth embraced 3½.
Balance & Spring: a monometallic balance with brass screws. Balance diameter 9.15 mm., thickness 0.60 mm. A 'self compensating' flat spiral spring with 11 turns.
Means of Regulation: An index on the balance cock registers against a divided scale with 'F S' and 'A R' engraved on the balance cock table.
Train Counts and Beat Rate:
Great wheel (barrel) 76
Centre wheel 72 pinion 10
Third wheel 60 pinion 9
Fourth wheel 70 pinion 8(the centre seconds wheel)
Escape wheel 15 pinion 7 (the lower pivot broken)
Beat rate 18,000
Motion work: cannon pinion 10
minute wheel 30, minute pinion 8
hour wheel 32
Self winding work: The angular motion of the self winding weight is limited by a block, B, one end of which carries a buffer spring. The other buffer spring is mounted in one end of the weight W. The weight support P carries the weight and is rivetted to the self winding pinion SWP. The pivots of this pinion run in jewels, one in the lower weight bridge and the other in the upper weight bridge U. Both of these bridges are secured to the barrel bridge BB. The pinion engages with a toothed sector T.
The pivots of the self winding ratchet SWR turn in a hole in the plate and a jewel mounted in the upper weight bridge U. The self-winding ratchet pinion engages with the crown wheel. Winding click 'C' is free to move beneath a shoulder screw in the underside of the sector T. A spring R is also mounted on the underside of the sector T it keeps the beak of the click in engagement with the teeth of the self winding ratchet wheel SWR. The spring R cannot ride off the click since it engages with a groove milled in the click edge. The back stop click C1 is free to turn under a shoulder screw in the barrel bridge BB, this click is held in contact with the ratchet wheel by the spring R'. The end of this spring also enters a groove milled in the click edge. The spring R1 is located in a recess in the barrel bridge and held by a screw.
When the swinging weight turns anticlockwise in the fig. the toothed sector T is driven in the direction of the arrow y by the self winding pinion SWP. The winding click C drives the self winding ratchet forward through a few tooth spaces and the pinion of this ratchet winds the mainspring since it engages with the crown wheel. The back stop click C' prevents the wheel from turning backwards during the reverse motion of the swinging weight when the click C rides back over a few teeth of the self winding ratchet SWR.
If the watch is wound manually the both clicks ride over the ratchet teeth. There is no barrel ratchet wheel click the back stop click C' prevents the mainspring unwinding during manual winding.
The up-and-down indicator:
The reserve of going is indicated by numbers on a disc D as these pass beneath an aperture in the dial. The number shown indicates the hours the watch will run without any further winding. When the watch is wound either manually by the button the indicator disc turns anti clockwise, the numbers pass beneath the opening and indicate an increase in the reserve of going time. When the number 40 has reached the aperture in the dial the disc remains stationary even if winding continues since the reserve of going is now at its maximum. If the watch runs without being wound the indicator disc will turn slowly in the clockwise direction and the numbers in the aperture will grow progressively smaller indicating a reduction in the running time still available. The sector of the indicator disc corresponding to the last 12 or 13 hours running time is coloured red serving to draw the attention of the owner to the fact that the watch should be wound manually if the watch is not to stop. Part of the indicator system is between the plates and part under the dial. It has to take into account the motion of the barrel ratchet wheel and also the motion of the barrel during running. This is accomplished by the use of a differential gear. An arbor J turns freely between the plate and the barrel bridge in which it pivots. A small arbor is mounted transversely on this main arbor and it carries the planetary pinion j which is free to rotate. This pinion engages with the contrate pinions j1 and j2 - these pinions are also free to rotate on the arbor J. The lower wheel is in mesh with the great wheel and the upper wheel through an idle wheel with the barrel ratchet wheel. As the barrel rotates in a clockwise direction j2 turns anti clockwise and since the bottom wheel is held by the great wheel the small pinion is caused to rotate thus causing the arbor which carries the assembly to rotate. If winding is not taking place and the barrel is rotating then the arbor will be caused to rotate in the opposite direction.
If both winding and running are taking place simultaneously then the motion of the arbor will represent the difference in the two. Arbor J carries a friction tight pinion S (15 teeth) which drives an idle wheel s (44 teeth) which in turn carries a pinion s1 (16 teeth). It is this pinion that drives the indicator wheel I. This wheel is only part cut with 36 teeth so the when the pinion meets the uncut portion of this indicator wheel the pinion S (15 teeth) on the end of the arbor is caused to slip.
Winding System: Conventional positive stem set keyless work.
Case: Diameter 34.2 mm., height 12.2 mm.
Movement: Diameter 29 mm., height 8.1 mm.
Provenance: Purchased in 1988 with the aid of funds from the Dingwall Bequest.
- Not on display
Latest: 3 (2017) movement not seen
3 (Jun 1995)
- Acquisition date
- Britain, Europe and Prehistory
- Registration number