| 摘要 |
1,240,297. Timepieces. LA NATIONALE S.A. Aug. 2, 1968 [Aug. 22, 1967], No. 37124/68. Heading G3T. A watertight winding stem for a timepiece comprises a tube 6, a crown 1 having a recess 2 and being movable to a neutral position in which the crown is tightened on the tube on elastic sealing member 8 and stop means for determining the neutral position and preventing over tightening of the crown. In the neutral position a screw-threaded flange 7 engages a screw-threaded collar 12 secured to the crown 1. A further seal 9 is also provided to ensure watertightness of the stem in the winding position shown in the right hand side of the figure. When the crown is screwed on to the tube 6 the seal 8 engages a conical surface 10 of the tube and the seal 9 is radially expanded by compression between a washer 11 and a flange 13 to engage the cylindrical surfaces of the recess 2 and the tube 6. Overtightening of the crown is prevented by the top of the tube 6 engaging the roof of the crown. Modifications including only a single seal are described and several modifications of the stop means are also described. |
