Device for leakproof fastening of a watch glass to a watch case

A device for the leakproof fastening of a watch glass to a watch housing, comprising an annular seal of a cylindrical general shape, said annular seal consisting of a compressible material having an inner annular projection at the upper end of said annular projection at the upper end of said annular seal, an annular groove positioned on an edge of the watch glass into which said annular projection is engaged, an outer lateral surface made on the upper part of the housing in order to receive the lower part of the inner face of said annular seal, the base of which comes into abutment against a bearing surface of the housing, and bezel fitted around said seal, at the same time compressing the latter radially, wherein the base of said annular seal has an annular bulge projecting at least from its outer lateral face, and wherein the inner lateral surface of the bezel fitted around this seal comprises two concentric cylindrical surfaces of different cross sections, the cylindrical surface of larger cross section being adjacent to the base of the bezel, these cross sections being slightly smaller than the cross sections of the outer lateral face of said annular seal and of said annular bulge in the non-compressed state, the base of said outer lateral surface of the upper part of the housing having an annular groove in order to receive a portion of said annular seal, said portion being deformed as a result of the fitting of the bezel, thereby ensuring the axial blocking of this annular seal.