Bending mechanism and endoscope

An endoscope comprising:

• an insertion portion extending along an axis from a proximal end to a distal end and configured to be inserted into a subject;
• an operation portion disposed proximal to the insertion portion;
• and
• a bending mechanism, at least part of which is provided at a distal end portion of the insertion portion, the bending mechanism comprising:
• a first tube extending along the axis and configured to be bent by a wire being pulled;
• a first guide formed in a cylindrical shape, the first guide being disposed in the first tube along the axis and configured to guide the wire;
• a second guide coupled to the first tube and configured to hold the first guide;
• a second tube extending along the axis and disposed proximal to the first tube, the second tube being connected to the operation portion;
• and
• a third guide disposed in the second tube along the axis,
• wherein a proximal end of the wire is connected to the operation portion, and
• wherein a proximal end of the first guide and a distal end of the third guide are spaced apart from each other by a predetermined gap along the axis.

An endoscope comprising:

• an insertion portion extending along an axis from a proximal end to a distal end and configured to be inserted into a subject;
• an operation portion disposed proximal to the insertion portion;
• and
• a bending mechanism, at least part of which is provided at a distal end portion of the insertion portion, the bending mechanism comprising:
• a first tube extending along the axis and configured to be bent by a wire being pulled;
• a first guide formed in a cylindrical shape, the first guide being disposed in the first tube along the axis and configured to guide the wire;
• a second guide coupled to the first tube and configured to hold the first guide;
• a second tube extending along the axis and disposed proximal to the first tube;
• and
• a third guide disposed in the second tube along the axis,
• wherein a proximal end of the wire is connected to the operation portion, and
• wherein the first guide is inserted into the third guide and extends proximally beyond a proximal end of the first tube to an intermediate position inside the third guide, and
• wherein a portion of the first guide that is positioned inside the third guide has a first predetermined length along the axis when the first tube is in a straight state, the first predetermined length being sufficient to maintain a proximal end of the first guide inside the third guide even when the first tube is in a bent state.