21,600 CHF
Constant Force Escapement Hess &Metford, Succ. rs de Heil & Hess a Geneve, “Chronometre Force Constant”, No. 2023. Made circa 1850. Very fine and extremely rare, 18K yellowgold half hunting-cased pocket watch with constant force escapement. Four-body with engine-turned covers “à grains d’orge”, polished borders, the front cover with scallop-edged polished chapter ring with radial black Roman numerals, inner minute track, reeded band. Hinged gold cuvette. White enamel with radial Roman numerals, outer minute track, subsidiary seconds. Blued steel spade hands. 42mm., frosted gilt, bar caliber, 10 jewels, constant force escapement with two stacked escape wheels using a tensioning spring to provide the constant force, large curved lever arm with counterpoise and recessed into the plate for security, cut bimetallic compensation balance, blued steel Breguet balance spring, index regulator. Dial and cuvette signed. Diam. 50 mm. Notes A constant force escapement incorporates a remontoire device to ensure constant force between the escape wheel and the balance. The escapement of the present watch works in the following way: The upper escape wheel comes to rest on the pallet fork which is at the same level. When the balance returns the anchor recoils which has the result of putting pressure on the internal tensioning spring. At the moment that the pallet exits, this spring is released and transmits power to the lower escape wheel. This wheel then gives the impulse to the anchor. T
Auctioneer:
Antiquorum
Date:
2008-11-16
