Thin Swiss 18k gold carillon grande sonnerie clockwatch Circa 1920

Gold minute repeating lever clockwatch 
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A fine and very rare Swiss, thin 18k gold, trip minute repeating, hunting cased, keyless, two-train, carillon grande sonnerie clockwatch with three hammers and three gongs, circa 1920. Attributed to Zenith. A polished case, hinged gold cuvette engraved with the technical details. White enamel dial, three-piece, with Arabic numerals, outer minute track, subsidiary seconds. Gold spade hands.
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A frosted gilt movement, double train with differential winding, 30 jewels, straight-line lever escapement, cut bimetallic compensation balance, blued steel Breguet balance spring, index regulator, striking the hours and quarters on three gongs with three hammers, Silence/Sonnerie selection lever on the bezel border, repeating activated by a push-piece in the band. Dial plate punched with César Racine’s Swiss patent number 18543 (for grande sonnerie) and Ditisheim’s patent number 15833 (for a silent regulator).
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Diameter: 48 mm
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Signed: No Name
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This type of minute-repeating Grande Sonnerie clockwatch movement with carillon on three gongs with three stacked hammers but without Petite Sonnerie were usually commercialised by Zenith.