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US 4,473,306 AGranted
Wristwatch case
AssigneeMontres Rado S.A.
InventorMarc Lederrey
Life of this patent
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AssigneeMontres Rado S.A.
InventorMarc Lederrey
Estimating the term…
A crystal (1) of a wristwatch case contains a sapphire base plate (2) which, in front view, entirely covers the body (3) of the case. That plate (2) is in turn entirely covered by a second sapphire plate (4) which is glued (5) to plate (2) very rigidly. The crystal (1) is fastened to the body (3) by screws engaged from the back side of the body (3) in sockets (7), a head (9) of which is captured between the two plates (2, 4) of the crystal (1). The position of the sockets (7) is exactly determined by a conical seat (10) of housings hollowed out in plate (2), at the bottom of which rests the conical head (9) of the sockets (7). Flats (14) are formed on the heads (9), so that the glue forms packings (15) preventing the sockets (7) from turning while screwing the crystal (1). The upper face (6) of the square (3) and the heads (9) of the sockets (7) are masked by a metal coating (12) deposited by vacuum spraying on the other side of plate (4). The crystal (1) is, furthermore, decorated with semicylindrical colored sapphire baguettes (16) glued in corresponding grooves (19) of plate (4).
For a wristwatch case having a flat sapphire crystal which masks the body of the case covering it entirely, and is fastened to the body by screws engaged from its back side in sockets integrated with the crystal, an improvement comprising each socket comprising a head firmly captured inside the crystal, said crystal formed of two sapphire plates glued to each other, said head captured between said two sapphire plates, said heads being masked by ornaments incorporated in the crystal.
Dependencies are inferred from the claim text.