Watch crystal bonded to watch case with low temperature solder material
AssigneeMontres Rado S.A.
InventorsPaul Gogniat, Eric Loth
Life of this patent
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Abstract
The watchcase essentially comprises a crystal 1, or other transparent part visible from the outside of the case, assembled to the body 2 or a bezel exclusively by way of a layer 3 of low-temperature solder, in the nature of a silver or tin solder. A layer of barrier coating 5, chromium for example, serves to avoid diffusion of solder in the liquid state to the surface of the crystal. The zone of junction may be masked by a metallic coating 4, and the grip of the solder may be improved with a supplementary junction layer 6. It is thus possible to make watchcases of distinguished appearance, comprising junction areas of narrower width than those required when cement is used for the assembly.
Claims17
A watchcase comprising a first part made of a transparent material being visible from outside of the case and a second part rigidly attached to the first, a layer of low-tmperature metal soldering material attaching said first and second parts formed between said first and second parts, characterized in that the first part of the case comprises a metal coating applied to that portion of its surface which meets the metal soldering layer, the said metal coating comprising at least three superimposed layers comprising
- a first layer located next to the said surface of said first part serving to bond said metal coating thereto and mask the area being soldered,
- a second layer superimposed on the first layer to restrain diffusion of said soldering material towards the first part and,
- a third layer located next to the said metallic soldering layer to give the latter a purchase on the coating.
Dependencies are inferred from the claim text.