Swiss gold open faced grande sonnerie clockwatch Circa 1910

Gold minute repeating lever clockwatch 
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A very fine and very rare Swiss, 18k yellow gold trip-minute repeating, keyless, two-train, grande sonnerie clockwatch, circa 1910. A polished case, strike/silent lever under the bezel. Hinged gold cuvette. White enamel dial, radial Roman numerals, outer minute track, Arabic five-minute numerals, subsidiary seconds. Blued steel spade hands. A rhodium-plated movement, Geneva striping decoration, 29 jewels, two-train with tandem winding, straight-line lever escapement, cut bimetallic compensation balance, blued steel Breguet balance spring, index regulator, striking and repeating with two hammers on two gongs, the repeating activated by a button in the crown. Dial signed.
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Diameter: 55 mm
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Signed: Ami Sandoz & Fils  Genève
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The movement is rusty and lacks elements.
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Ami Sandoz & Fils
The firm was active from the early 19th century and won a silver medal for horology at the Paris Universal Exhibition in 1878.