Endoscope and cylindrical structure for endoscope
An endoscope includes a cylindrical member, a first outward flange including a first cutout, a projection projecting inward from an internal circumferential surface of a hole formed in a distal end portion of an insertion section of the endoscope, and capable of being engaged with the first cutout, an elastic member to urge the cylindrical member toward a bottom portion of the hole, and a projecting portion formed to project from the internal circumferential surface of the hole and including a surface facing the bottom portion of the hole.
1. An endoscope comprising:
an insertion section having (1) a longitudinal axis, (2) a distal end, (3) an internal circumferential surface that defines a hole with an opening in the distal end and extending from the opening along the longitudinal axis, (4) a first projection projecting inwardly in a radial direction from the internal circumferential surface, and (5) a second projection projecting inwardly in a radial direction from the internal circumferential surface that is (a) spaced from the first projection and (b) located between the first projection and the distal end;
a cylindrical member (1) disposed in the hole, (2) extending along the longitudinal axis, (3) having an external circumferential surface, and (4) having a first outward flange provided on the external circumferential surface that extends outwardly from the external circumferential surface; and
an elastic member provided on the external circumferential surface of the cylindrical member and located between the first projection and the second projection; wherein:
the outward flange has end portions that (1) are opposed to each other in a circumferential direction of the longitudinal axis and (2) define a first cutout;
the first projection is disposed in the first cutout; and
the elastic member (1) is elastically deformable and configured to slide over the second projection when the cylindrical member is inserted into the hole of the insertion section and (2) interacts with the second projection to urge the cylindrical member away from the distal end of the insertion section.
2. The endoscope according to claim 1 , wherein:
the cylindrical member has a bottom portion; and
the endoscope further comprises another elastic member (1) located in the hole, (2) abutting against the bottom portion and (3) elastically deformed when the cylindrical member is disposed in the hole such that the another elastic member urges the cylindrical member toward the opening.
3. The endoscope according to claim 2 , wherein the elastic member is less easily deformable than the another elastic member.
4. The endoscope according to claim 1 , wherein the second projection includes an inclined surface which (1) is formed in an arc or ring shape, (2) is inclined with respect to the longitudinal axis from the internal circumferential surface towards the opening, and (3) interacts with the elastic member.
5. The endoscope according to claim 1 , further comprising:
a regulating portion (1) provided on the external circumferential surface of the cylindrical member and (2) having a shape that will not fit into the opening of the hole.
6. The endoscope according to claim 1 , wherein:
the cylindrical member has a bottom portion;
the endoscope further comprises a second outward flange (1) provided on the external circumferential surface of the cylindrical member, (2) located between the first outward flange and the bottom portion and (3) defining a second cutout shifted in the circumferential direction from the first cutout; and
when the cylindrical member is inserted into the hole, the first projection passes through the second cutout.
7. The endoscope according to claim 1 , wherein the insertion section includes:
a base member that forms a part of the hole and receives the cylindrical member; and
a cover member (1) that forms a part of the hole, including the opening of the hole, and (2) includes the first projection and the second projection.
8. The endoscope according to claim 7 , wherein:
the base member defines a first portion of the internal circumferential surface, the first portion including (1)
a small-diameter portion having a first diameter and formed on a side of the internal circumferential surface and (2)
a large diameter portion having a second diameter and formed on a side of the internal circumferential surface;
the large diameter portion is between the small-diameter portion and the cover member;
the second diameter is larger than the first diameter; and
the second outward flange is disposed in the large diameter portion.
9. The endoscope according to claim 1 , wherein:
the second projection includes circumferentially opposed end portions, and
the first projection is disposed between the end portions when viewed from the opening.
10. The endoscope according to claim 1 , wherein:
the insertion section includes an observation window; and
the cylindrical member is a nozzle unit including a fluid channel to feed fluid to the observation window.
11. The endoscope according to claim 1 , wherein the cylindrical member is a lens unit.
12. The endoscope according to claim 1 , wherein the first projection is configured to engage the first cutout.