Watch case provided with a cap of hard material
AssigneeMontres Rado S.A.
InventorPaul Gogniat
Life of this patent
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Abstract
A cap (2) is made of sintered hard metal and has on the inside a cylindrical surface (20) and a frusto-conical surface (21) that are true ground. The cap's cylindrical surface (20) is fitted with radial play around an outer cylindrical surface (9) of an underlying middle (1) and the cap's frusto-conical surface (21) has the same inclination as a subjacent frusto-conical surface (14) on the outside of the middle. The cap (2) and the middle (1) are secured to one another by a ring of deformable material sandwiched between their cylindrical surfaces (9, 20). On the outside the cap (2) is formed over its thicker main portion (18) with a trued and polished surface (22) having the same inclination as its inside frusto-conical surface (21) such as to provide the thicker portion (18) with a parallelogrammatic cross-section.
Claims10
A watch case comprising a coaxial assembly of two constituent parts, one being a middle made of a machinable material and the other being a cap made of a hard material covering the middle, wherein the middle has an upper portion limited externally by a cylindrical surface, and a lower portion limited externally by a frusto-conical surface, wherein the cap has a thicker portion internally limited by a cylindrical surface having a diameter greater than that of the middle's cylindrical surface, such as to provide a radial gap between said cylindrical surfaces, and downwards by a frusto-conical surface having the same inclination as that of the middle and which is in contact therewith, and wherein an annular fixing element made of deformable material is fitted between said cylindrical surfaces.
Dependencies are inferred from the claim text.