Self-winding gold-cased lever wrist-watch with brown leather strap

Description — British Museum

Pedometer winding watch, wound by the movement of the watch within its case. Club-tooth lever escapement. Silvered metal dial with gilt Arabic numerals; blued steel hands. 9ct gold case with symbol for Glasgow import.

Curator's comments — British Museum

Comment from Richard Good, Catalogue of Watches in the British Museum. Vol. V (Unpublished manuscript) Made by ROLLS Switzerland, c. 1930 Gold cased self winding wrist watch with a club tooth escapement. Signature: On the dial ROLLS SWISS MADE ATO. On the movement is 'HATOT'S PATENTS(1) IN ALL COUNTRIES FIFTEEN 15 JEWELS THREE 3 ADJS SWISS MADE'. Case: A 9 ct. gold case with import marks for Glasgow 1930. Also marked 3 and 107026. A steel lining is within the case and is of channel section. The movement runs up and down inside this piece on ball bearings and in the process effects winding. An aperture reveals the dial. Dial & Hands: A silvered dial with raised gilt Arabic numerals. On the back of the dial is 9 539. The hands of blued-steel of modern mitre design. Movement: Ebauche Marks 340. Frame: A nickel silver movement. On the back plate is an additional thick bridge to add weight to the movement, this bears the inscription detailed above and is held in place by a single screw. It also carries one of the buffer springs. The barrel bridge carries the other buffer spring. There is another bridge for the train and cocks for the escape wheel, the pallets and the balance. Under and on the escape wheel cock is 232, under the pallet cock is 34. Under the train bridge is 340. One of the barrel bridge securing screws is missing. Barrel and Mainspring: Going barrel: I diameter 7.0 mm., height 1.25 mm. Mainspring: height 1.20 mm., thickness 0.085 mm. Barrel Arbor: diameter 2.3 mm., snailed. Hooking: A slipping mainspring. There is a separate piece of mainspring just over a turn long which rests against the barrel wall and has a round hook which engages with the spring end. Train: All the brass wheels are 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 rubbed in. Ruby endstones to the balance jewels. 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 mixed escapement. No. of teeth embraced 3½. Balance & Spring: A split bimetallic balance with brass screws. Balance diameter 6.9 mm, thickness 0.6 mm. A blued-steel flat spiral spring with 11 ¼ turns. Means of Regulation: An index on the balance cock registers against a divided scale with 'A R' engraved on the balance cock table. Train Counts and Beat Rate: Great wheel 68 (barrel) Centre wheel 64 pinion 10 Third wheel 60 pinion 8 Fourth wheel 60 pinion 8 Escape wheel 15 pinion 6 Beat rate: 18,000 Motion work: cannon pinion 10 minute wheel 30, minute pinion 8 hour wheel 32 Self Winding System: The movement H has grooved edges to locate the the ball bearings b. 1,2,3 and 4 also run in matching grooves in the channel insert in the case. Lever L has a forked end which engages with a pin P fixed to the case edge. Movement travel is limited by stops and cushioned by the buffer springs a1 and a2. Ratchet C1 is fixed to the lever L which gathers teeth on the ratchet wheel R which is provided with a second ratchet to prevent backward motion. Wheel R, which has 80 teeth carries a pinion of 8 which meshes directly with the barrel ratchet wheel of 50 teeth. Winding system: When the case is opened a serrated wheel is disclosed at about 2 o'clock. On pressing this in a gear which it carries engages with the minute wheel and the hands can be set. Dimensions: Case: length 31.6 mm., width 17.0 mm., height 9.0 mm., over the glass. Movement: length 25.5 mm., width 13.0 mm., height 6.0 mm. Provenance: Purchased in 1982 with the aid of funds made available by Stanley H Burton. Note: (1) French patents number 704910, 38984 and 39523 were taken out by Leon Hatot. These patents covered many different designs, the Rolls being one. Literature: For a write up on Leon Hatot by Henry L Belmont see 'Horlogerie Ancienne', No. 12/2/1982. The Rolls is discussed on pp. 101 and 102.