Important collector's watches, wristw...

Hotel Richemond, Geneva, Apr 13, 2002

LOT 604

Walter Prendel, Groïtzsch I/SA, started 1927, finished 1928. Exceptional and unique large double-barrel, six-minute flying tourbillon regulator with inclined balance and 30-hour winding indicator pocket chronometer.

C. 900 silver with gold hinges and lips, ?variée?, ?grande gouge?, with stepped bezels, silver hinged glazed cuvette, No. 1928 made by Karl Richter of Glashütte. D. White enamel, radial Roman numerals, outer minute ring, subsidiary sunk seconds at 3 o?clock, sunk up-and-down indicator symmetrically at 9 o?clock. Blued steel ?spade? hands. M. 47.2 mm. (21???), 13 mm. thick, nickel, half plate, Helwig two barrel system, each with six turns of which only four are utilized by means of a stop work, going train with unusual, almost triangular, involute teeth, 23 jewels, 6-minute flying tourbillon driven from the center wheel, extremely delicate Helwig-type carriage built around the third wheel pinion carrying the fourth wheel and the lateral lever escapement with gold calibrated pallet fork, having a special poising pin protruding between the lever and the escape wheel, convex entry pallet, concave exit pallet to equalize both lifts, Guillaume anibal-brass, cut-bimetallic, 30o inclined, compensation balance with eight gold temperature adjustment screws and four gold quarter screws, free-sprung blued special steel alloy balance spring with outer terminal curve, the pallet fork is inclined 23o and the escape wheel 15o, Stanley type (English patent No. 5062 of March 21, 1891) differential type winding indicator with transmission to the dial through pierced barrel arbor, pin-set. Signed on dial and movement, case signed by the casemaker. Diam. 60.6 mm., 18 mm. thick (with crystal).