Distal-end cover, insertion device attached with distal-end cover, and endoscope including insertion device

1. An insertion device comprising:

a distal-end component at a distal end of a flexible tube for insertion into a lumen, the distal-end component being configured to hold an optical element for observation in the lumen;

a circular electrical insulation part on a more distal end than the flexible tube, the electrical insulation part including a first color;

an indicator at the distal-end component, the indicator including a second color;

a first cover adapted to be attached over the distal-end component, wherein the first cover hides all portions of the indicator in a first state when the first cover is attached at a first prescribed position and the first cover does not hide at least a portion of the indicator in a second state when the first cover is not attached at the first prescribed position, the first cover including a third color different from the second color; and

a second cover adapted to be coupled to a proximal portion of the first cover attached to the distal-end component, wherein the second cover hides all portions of the electrical insulation part in a third state when the second cover is attached at a second prescribed position and the second cover does not hide at least a portion of the electrical insulation part in a fourth state when the second cover is not attached at the second prescribed position, the second cover including a fourth color different from the first color,

wherein the first cover has a finer surface roughness than the second cover, and

the second cover has a higher elasticity than the first cover.

2. The insertion device of claim 1 , wherein

the first color of the electrical insulation part is equal to the second color of the indicator, and

the third color of the first cover is equal to the fourth color of the second cover.

3. The insertion device of claim 2 , wherein a part of the first cover that hides the indicator includes the third color.

4. The insertion device of claim 1 , wherein the first cover and the second cover comprise an electrically insulating material to prevent electrical conduction between the distal-end component and an outside.

5. The insertion device of claim 1 , further comprising an opening to optically expose the optical element for observation in the lumen, wherein

the indicator is positioned in the distal-end component so that when the first cover is attached to the distal-end component, the indicator is located adjacent the opening.

6. The insertion device of claim 1 , wherein the first cover is fixed to a position defined in an exterior of the distal-end component via a locking unit between the distal-end component and the first cover.

7. The insertion device of claim 6 , wherein, in the prescribed position, the first cover is attached to the distal-end component in a state that the first cover is prevented from dropping from the distal-end component.

8. The insertion device of claim 1 , wherein the distal-end component comprises a treatment-tool conduit for a treatment tool to pass through, the treatment tool being configured to apply an electrical current.

9. The insertion device of claim 8 , wherein

the distal-end component comprises a treatment-tool swing base configured to swing an end portion of the treatment tool, and

the first cover comprises a cutout from which the end portion of the treatment tool comes out.

10. The insertion device of claim 1 , wherein the first cover and the second cover are adapted to be attachable and detachable to the distal-end component.

11. The insertion device of claim 1 , wherein the first cover and the second cover are separate members.

12. The insertion device of claim 11 , wherein the second cover is shorter than the first cover in a longitudinal direction.

13. The insertion device of claim 11 , wherein

the first cover comprises an outer peripheral surface, the outer peripheral surface including the proximal portion having a first joint surface, the first joint surface extending in a longitudinal direction and being offset in an inwardly radial direction from the outer peripheral surface, and

the second cover comprises an inner peripheral surface, the inner peripheral surface including a distal portion having a second joint surface, the second joint surface extending in a longitudinal direction and being offset in an outwardly radial direction from the inner peripheral surface, the second joint surface being configured to couple with the first joint face.

14. The insertion device of claim 11 , wherein the first cover comprises a slit in the proximal portion.

15. The insertion device of claim 1 , further comprising a locking unit between the distal-end component and the first cover, the locking unit being configured to fix the first cover to a position defined in an exterior of the distal-end component,

wherein the locking unit comprises a projecting locking pin and a recessed locking hole configured to couple to each other.

16. An endoscope comprising the insertion device of claim 1 , as an insertion unit to be inserted into the lumen.

17. A distal-end cover for use with an endoscope,

the endoscope comprising:

a distal-end component at a distal end of a flexible tube for insertion into a lumen, the distal-end component adapted to hold an optical element for observation in the lumen;

a circular electrical insulation part on a more distal end than the flexible tube, the electrical insulation part including a first color; and

an indicator at the distal-end component, the indicator including a second color,

wherein the distal-end cover is adapted to be attached to the distal-end component of the endoscope, and the distal-end cover comprises:

a first cover adapted to be attached over the distal-end component, wherein the first cover hides all portions of the indicator in a first state when the first cover is attached at a first prescribed position and the first cover does not hide at least a portion of the indicator in a second state when the first cover is not attached at the first prescribed position, the first cover including a third color different from the second color; and

a second cover adapted to be coupled to a proximal portion of the first cover attached to the distal-end component, wherein the second cover hides the all portions of the electrical insulation part in a third state when the second cover is attached at a second prescribed position and the second cover does not hide at least a portion of the electrical insulation part in a fourth state when the second cover is not attached at the second prescribed position, the second cover including a fourth color different from the first color,

wherein the first cover has a finer surface roughness than the second cover, and

the second cover has a higher elasticity than the first cover.

18. An insertion device comprising:

a distal-end component at a distal end of a flexible tube for insertion into a lumen, the distal-end component adapted to hold an optical element for observation in the lumen;

a circular electrical insulation part on a more distal end than the flexible tube, the electrical insulation part including a first color;

an indicator at the distal-end component, the indicator including a second color;

a cover adapted to be attached over the distal-end component, the cover comprising a first cover and a second cover coupled to a proximal portion of the first cover,

wherein the cover hides all portions of the indicator and the electrical insulation part in a first state when the cover is attached at a prescribed position and the cover does not hide at least a portion of one or more of the indicator and the electrical insulation part in a second state when the cover is not attached at the prescribed position, the first cover including a third color different from the second color, the second cover including a fourth color different from the first color; and

wherein the first cover has a finer surface roughness than the second cover, and

the second cover has a higher elasticity than the first cover.