| 摘要 |
Various methods and mechanical devices for providing manipulation and steering of the bending section of an endoscope having a sheath thereon is disclosed. In one embodiment, the longitudinal center axis of a biopsy type is aligned with the longitudinal center of the insertion tube, both being in common with the instantaneous bending center of the insertion tube. The insertion tube is capable of only right and left movement through steering but is also rotatable with respect to the handle to permit the tip to be positioned in any desired location. In an alternative embodiment, the instantaneous bending center is radially offset from the longitudinal center of the insertion tube. The hinges are positioned in the bending section of the insertion tube for locating the instantaneous center of bending at a desired location in a groove. Four, or in an alternative embodiment, three cables are provided for controlling the movement and steering of the bending section. Because the cables are not symmetrically located with respect to the instantaneous bending center, the mechanical control assembly is designed to take into account the difference between the movements of the respective cable through the full range of motions. In an alternative embodiment, the channel is located radially offset from the instantaneous center of bending and the biopsy tube assembly is made stretchable or compressible to ensure that the biopsy tube end remains aligned with the end of the insertion tube end.
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