Safety valve for diver's timepiece

摘要

This valve (1) for a watch case comprises a head (3) and a tube (4) onto which the head can be screwed. A stem (8) fixed to a core (5) borne by the head is surrounded by a return spring (7) bearing, on the one hand, under the head and, on the other hand, onto a bottom (3) exhibited by the tube through a ring (14) and a first packing (6). A second packing (18) is mounted under the head in line with the tube. When the head is screwed down the second packing (18) is compressed and the valve is inoperative and at the same time totally sealed. When the head is unscrewed the first packing (6) is able to rise up against the return force of spring (7) if the fluid pressure prevailing within the case is higher than that on the exterior thereof. An excessive interior pressure which can damage the case is thus avoided.