Patent 7182507 was granted and assigned to Seiko Instruments on February, 2007 by the United States Patent and Trademark Office.
To provide a portable timepiece capable of interchanging a part at a surrounding of a crown when a screw lock function is deteriorated. A premise is established by a portable timepiece screwing to lock a crown urged in a direction of separating from a case body by a coil spring (urging member) included in a winding stem pipe to the winding stem pipe attached to the case body. The winding stem pipe includes a winding stem pipe main body inserted into a pipe attaching hole of the case body and fixed in liquid tight by using a brazing member, and a ring fitted to a case body outside projected portion of the main body removably by being stopped to rotate and provided with a male screw portion to which the crown is removably screwed at an outer periphery thereof. A ring holding member is pinched between the ring and a holding portion of the case body outside projected portion. The ring holding member holds the ring at an outer periphery of the case body outside projected portion and releases the ring from being held thereby when an external force sufficient for releasing the holding state is exerted to the ring.