Swiss pocket watch with patented wind mechanism Circa 1880

An almost as new silver pocket watch by Grasset & Co.
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A Swiss, very rare and almost as new gentleman’s pocket watch with a patented crown spring winding mechanism by Isaac Grasset, circa 1880.
Silver engine turned, à goutte case with case maker’s punch mark and glazed movement. Enamel dial with Arabic numerals, outer minutes track with five minutes numerals, auxiliary seconds and gold Louis XV hands. Frosted, gilt bridge movement, crown winding via tension spring coiling up the stem, Patent 5019 14528, with screw compensation balance and counterpoised lever.
Movement signed.
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Diameter: 51 mm
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Weight: 73 g
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Signed: Isaac Grasset & Cie. à Genève
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The Swiss Patent 5019 and 14528 by Isaac Grasset In the early 1880s Isaac Grasset designed an interesting alternative power source in the form of a spring coiling up the stem (Swiss patent No. 120, later improved in No. 5019). In 1897, he patented a stem winding and setting mechanism for the arrangement, as found in this watch (Swiss patent No. 14528). He also patented a fascinating constant force escapement and applied it to his design.