| 摘要 |
<p>A device for varying the screwing depth is provided in the screw thread of a mouthpiece, wherein internal screw thread segments of a cap engage upper turns of said screw thread when the cap is screwed onto the mouthpiece, and disengage from lower screw thread turns when the cap is unscrewed from the mouthpiece, and in the beginning of the cap unscrewing motion the cap may have no longitudinal motion or a descending longitudinal motion for actuating a device for cutting the wall of a container to which said mouthpiece device is attached.</p> |
