Swiss pocket watch with patented wind mechanism Circa 1880

Unique and almost as new pink gold pocket watch by Grasset & Cie.
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A Swiss, unique and almost as new gentleman’s pocket watch with a patented crown spring winding mechanism by Isaac Grasset, circa 1880.
18 Carat pink gold, polished, à goutte case with case maker’s punch mark AM and glazed movement. Enamel dial with Arabic 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.
Dial and movement signed.
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Diameter: 51 mm
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Weight: 99 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 1880’s 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 an interesting constant force escapement and applied it to his design.