JP2017012554A - Endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an endoscope whose tip end part can be made thin, for achieving size reduction, and a cover body disposed on the tip end part can be fixed in a water tight state for preventing falling.SOLUTION: An endoscope 1 comprises: an insertion part 2 to be inserted into an analyte; a cylindrical resin cover 10 provided at the tip of the insertion part 2, and having a step part 11 whose base end part becomes thinner; a first engagement part 13 which is disposed in an outer diameter of the step part 11; a second engagement part 32 which engages with the first engagement part 13 in the outer diameter of the step part 11 for connecting the resin cover 10 so as not to move toward a long axis direction of the insertion part 2; and an external pipe 26 which is connected to cover the step part 11, and coats a connection part of the first engagement part 13 and the second engagement part 32.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an endoscope in which an outer diameter of an insertion portion to be inserted into a subject is particularly small.

  As is well known, endoscopes are widely used for observation and treatment of living bodies (inside body cavities), inspections and repairs in industrial plant facilities, and the like.

  In particular, among medical endoscopes, for example, those used for otolaryngology have a very small outer diameter of the insertion portion and a small diameter.

  In such a conventional endoscope, an observation window is arranged at the center of the distal end of the insertion portion, and an illumination window that irradiates the region to be examined with illumination light from an illumination light guide fiber around the observation window Is provided.

  For example, Patent Document 1 includes an observation window and a transparent member that can transmit the irradiation light emitted from the irradiation unit so as to cover the distal end surface of the irradiation unit that emits the irradiation light so as to surround the outer periphery of the observation window. The technique of the front-end | tip part of the provided endoscope is disclosed.

JP 2013-106907 A

  By the way, the light guide fiber has low resistance to cleaning, sterilization, and disinfection, and a transparent member that is a transparent cover body as a protective member as disclosed in the distal end portion of a conventional endoscope is required. This transparent member needs to ensure water tightness and not fall off from the distal end portion of the endoscope.

  However, the conventional endoscope has a structure in which a transparent member, a distal end outer cylinder, and an outer tube are laminated, and there is a problem that causes the outer diameter of the distal end to increase.

  Furthermore, since the conventional transparent member has a structure that is simply bonded to and integrated with the objective lens frame, the objective lens holding cylinder, and the objective lens, there is a problem that the transparent member may drop off.

  Therefore, the present invention has been made in view of the above circumstances, and an endoscope that can be reduced in size by reducing the diameter of the distal end portion and that prevents the dropout by fixing the cover body provided at the distal end portion in a watertight manner. The purpose is to provide.

  An endoscope according to an aspect of the present invention includes an insertion portion that is inserted into a subject, a cylindrical resin cover that is provided at a distal end of the insertion portion, and has a step portion with a proximal end portion having a small diameter, A first engagement portion provided within an outer diameter of the step portion, and engages with the first engagement portion within an outer diameter of the step portion so that the resin cover extends in a longitudinal axis direction of the insertion portion. A second engagement portion that is connected so as not to move; and an outer tube that is connected so as to cover the stepped portion and covers the connection portion formed by the first engagement portion and the second engagement portion. I have.

  According to the present invention, it is possible to provide an endoscope that can be reduced in size by reducing the diameter of the distal end portion and that prevents the dropout by fixing the cover body provided at the distal end portion in a watertight manner.

The perspective view which shows the structure of the front-end | tip part of the insertion part with which the endoscope of 1 aspect of this invention is provided. The same fragmentary sectional view which shows the constitution of the tip part of the insertion part The exploded perspective view which shows the connection structure of a transparent resin cover and a nozzle | cap | die similarly Side view showing the state where the transparent resin cover and base are connected Sectional drawing which shows the structure of the front-end | tip part of the insertion part of a 1st modification same as the above Sectional drawing which shows the state with which the transparent resin cover and slit serpentine tube of the 2nd modification were connected similarly The exploded perspective view which shows the state to which the transparent resin cover and slit serpentine of a 2nd modification are connected similarly The perspective view which shows the state with which the transparent resin cover and slit serpentine tube of the 2nd modification were connected similarly The side view which shows the state in which the transparent resin cover and nozzle | cap | die of a 3rd modification are connected similarly The side view which shows the state with which the transparent resin cover and nozzle | cap | die of the 3rd modification were connected similarly The side view which shows the state in which the transparent resin cover and nozzle | cap | die of a 4th modification are connected similarly The side view which shows the state with which the transparent resin cover and nozzle | cap | die of the 4th modification were connected similarly The exploded perspective view which shows the connection structure of the transparent resin cover of a 5th modification, and a nozzle | cap | die similarly The side view which shows the state with which the transparent resin cover and base of the 5th modification were connected similarly The fragmentary sectional view which shows the state with which the transparent resin cover and nozzle | cap | die of the 6th modification were connected similarly Sectional drawing which shows the state with which the transparent resin cover and nozzle | cap | die of 6th modification were connected similarly Sectional drawing which shows the state in which the transparent resin cover of another form which concerns on a 7th modification, and a nozzle | cap | die are connected The side view which shows the structure of the nozzle | cap | die of another form which concerns on a 7th modification as same as the above The fragmentary sectional view which shows the structure of the insertion part to which the transparent resin cover and braid | blade of the 8th modification were connected similarly The fragmentary sectional view which shows the state with which the transparent resin cover and braid | blade of the 8th modification were connected similarly

  Hereinafter, the endoscope according to the present invention will be described. In the following description, the drawings based on each embodiment are schematic, and the relationship between the thickness and width of each part, the thickness ratio of each part, and the like are different from the actual ones. It should be noted that the drawings may include portions having different dimensional relationships and ratios between the drawings.

  Note that the endoscope in the following description of the configuration will be described by taking a so-called flexible endoscope having an insertion portion flexible for insertion into the digestive organs of the upper or lower part of the living body, but is not limited thereto. In addition, the technique can be applied to a so-called rigid endoscope having a hard insertion portion used for surgery.

  First, an endoscope according to one embodiment of the present invention will be described with reference to the drawings. 1 is a perspective view showing the configuration of the distal end portion of the insertion portion provided in the endoscope, FIG. 2 is a partial sectional view showing the configuration of the distal end portion of the insertion portion, and FIG. 3 shows the connection configuration of the transparent resin cover and the base. FIG. 4 is an exploded perspective view, and FIG. 4 is a side view showing a state in which the transparent resin cover and the base are connected.

  The endoscope 1 according to the first embodiment of the present invention has an insertion portion 2 to be inserted into a subject as shown in FIG. This insertion part 2 has flexibility, and the base end is connected with the operation part which is not shown in figure.

  The insertion portion 2 has an observation lens 21 as an observation window which is an objective optical system at the distal end portion 3 provided at the distal end, and a cylindrical shape which is a transparent member as a distal end cover provided around the observation lens 21. The transparent resin cover 10 is provided.

  The insertion portion 2 may be configured to include a bending portion that is connected to the distal end portion 3 and is bent by a remote operation from the operation portion. Note that the insertion portion 2 here has a small outer diameter of about 2 to 5 mm as the medical endoscope 1.

  As shown in FIG. 1, an observation lens 21 as an observation window is disposed at the distal end portion 3, and an optical fiber bundle as a light transmission member that irradiates irradiation light into the body of the subject around the observation lens 21. A light guide fiber 24 is disposed inside.

  In this endoscope 1, an observation optical system 20 that is a lens group including an observation lens 21 is held by a cylindrical lens frame 23, and an image guide 22 is provided at the base end of the observation optical system 20. This is a so-called fiber endoscope.

  The image guide 22 is held in the lens frame 23 with its distal end inserted and covered with a flexible outer skin 28 from the base end of the lens frame 23 and disposed in the insertion portion 2.

  The light guide fiber 24 is disposed so that the tip portion covers the periphery of the lens frame 23, and is coated so that the tip is abutted against the transparent resin cover 10.

  The light guide fiber 24 is covered with a flexible interior resin tube 27 from the base end of the base 30 joined to the transparent resin cover 10 and disposed in the insertion portion 2.

  A step portion 31 having a small diameter in the inner diameter direction is formed at the base end portion of the base 30, and the tip portion of the blade 25 that is a metal mesh tube is joined to the step portion 31 by soldering or welding.

  A stepped portion 11 having a small diameter in the inner diameter direction is also formed at the base end portion of the transparent resin cover 10, and the stepped portion 11 is covered with a distal end portion of an exterior resin tube 26 that is a serpentine tube as an outer skin.

  The exterior resin tube 26 covers the base 30 and the blade 25 from the base end of the transparent resin cover 10. The exterior resin tube 26 may have a configuration in which a resin tube is bonded, or may be configured to be resin-molded directly on the stepped portion 11 of the transparent resin cover 10, the base 30, and the outer peripheral surface of the blade 25.

  In addition, the outer diameters of the stepped portion 11, the base 30 and the blade 25 of the transparent resin cover 10 are sized so as not to cause a step.

Here, the configuration of the transparent resin cover 10 and the base 30 and the configuration for connecting them together will be described in detail below.
The transparent resin cover 10 is formed of a transparent resin such as polysulfone, polycarbonate, polyamide (nylon), polyester, acrylic, and the like, as shown in FIG. 3 and FIG. It has the opening part 12 in which the front-end | tip of the lens frame 23 is arrange | positioned.

  Within the outer diameter of the base end portion of the step portion 11 of the transparent resin cover 10, there are a plurality of engaging recesses 13 in the circumferential direction as engaged portions constituting one of the substantially T-shaped dropout prevention portions here. , At least two are formed. The engaging recess 13 is cut out from the base edge of the step 11 toward the tip.

  The base 30 is a metal ring member formed of stainless steel or the like, and here, an engagement convex portion 32 constituting the other of the substantially T-shaped convex-shaped drop-off preventing portion is provided so as to extend from the tip. A plurality, at least two, are formed in the direction.

  The transparent resin cover 10 and the base 30 are formed so that the inner and outer diameters are substantially the same. Further, the engaging concave portion 13 of the transparent resin cover 10 and the engaging convex portion 32 of the base 30 have substantially the same similar shape, and are formed so that the intervals in the circumferential direction are the same.

  The transparent resin cover 10 and the base 30 are connected to each other by engaging the engaging convex portion 32 with the engaging concave portion 13 and fitting it therewith. In addition, the engaging convex part 32 is formed in the outer diameter of the step part 11 of the transparent resin cover 10.

  That is, the engagement convex part 32 which becomes the substantially T-shaped key provided in the base 30 engages with the engagement concave part 13 which becomes the substantially T-shaped key groove formed in the transparent resin cover 10. The transparent resin cover 10 is prevented from falling off the base 30 so that it does not move in the axial direction (the longitudinal axis direction of the insertion portion 2 and the distal end portion 3) so as not to come off.

  Note that the engaging recess 13 and the engaging protrusion 32 as key structures that prevent the transparent resin cover 10 from being detached from the base 30 are not limited to a substantially T-shape, and the transparent resin cover 10 and the base 30 are not limited. Any shape may be used as long as they are connected so that they do not come off in the axial direction.

  Moreover, although the structure which formed the engagement recessed part 13 in the transparent resin cover 10 and provided the engagement convex part 32 in the nozzle | cap | die 30 was illustrated here, it is good also as a structure which provided the uneven | corrugated to engage reversely.

  Furthermore, the engagement concave portion 13 and the engagement convex portion 32 are formed at two positions symmetrical with respect to the center point of the transparent resin cover 10 and the base 30 so that the transparent resin cover 10 and the base 30 are orthogonal to the axial direction. Can be assembled by sliding.

  Further, when there are three or more engaging concave portions 13 and engaging convex portions 32, the engaging convex portions 32 are thinned, expanded within the range of elastic deformation, and engaged with the engaging concave portions 13. The joint recess 13 and the engagement projection 32 can be assembled.

  After the engagement concave portion 13 and the engagement convex portion 32 are connected in this way, the lens frame 23 that holds the observation optical system 20 that is accommodated in the interior resin tube 27 and the tip portion extends from the interior resin tube 27, an image The guide 22 and the light guide fiber 24 are assembled in the engagement recess 13 and the engagement protrusion 32.

  At this time, the lens frame 23, the image guide 22, and the light guide fiber 24 that are contained in the insertion portion 2 and are enclosed in the distal end portion 3 are filled with an adhesive for maintaining watertightness. Is done.

  Then, after the blade 25 is joined to the step portion 31 of the base 30, as shown in FIG. 2, the exterior resin tube 26 is integrally covered from the step portion 11 of the transparent resin cover 10 to assemble the insertion portion 2. It is done.

  Thus, the insertion portion 2 of the endoscope 1 has a configuration in which the base end side is covered with the exterior resin tube 26 from the step portion 11 of the transparent resin cover 10, and in particular, the transparent resin cover 10, the base 30, and the like. Since the connecting portion is covered with the exterior resin tube 26, it is configured to be reliably watertight.

  As described above, in the endoscope 1 according to the present embodiment, the engagement convex portion 32 of the base 30 is engaged with the engagement concave portion 13 of the transparent resin cover 10 at the distal end portion 3 of the insertion portion 2. Since the transparent resin cover 10 has a mechanical connection structure that prevents the transparent resin cover 10 from coming off in the axial direction (longitudinal axis direction of the insertion portion 2 and the distal end portion 3) with respect to the base 30, the falling off of the transparent resin cover 10 is prevented. Can do.

  Furthermore, since the endoscope 1 has a structure in which the transparent resin cover 10 of the insertion portion 2 and the base 30 are connected without being stacked and covered with an exterior resin tube 26 that is an outer tube, the distal end portion 3 is attached to the endoscope 1. The diameter can be reduced and the size can be reduced. As a result, the insertion portion 2 of the endoscope 1 can also be reduced in diameter.

(First modification)
FIG. 5 is a cross-sectional view showing the configuration of the distal end portion of the insertion portion of the first modification.
In the above description, the endoscope 1 is exemplified as a so-called fiber endoscope. For example, as shown in FIG. 5, the light guide fiber 24 is used as a detection fiber as a light transmission member, and the illumination fiber 41 is formed in a spiral shape. By applying the above-described connection structure of the transparent resin cover 10 and the base 30 to the scanning endoscope provided with the actuator 42 to be driven, the transparent resin cover 10 is prevented from falling off, and the distal end portion 3 and the insertion portion 2. The diameter can be reduced.

(Second modification)
FIG. 6 is a cross-sectional view showing a state in which the transparent resin cover of the second modified example and the slit serpentine are connected, and FIG. 7 is an exploded perspective view showing a state in which the transparent resin cover of the second modified example and the slit serpentine are connected. FIGS. 8A and 8B are perspective views showing a state in which the transparent resin cover of the second modification and the slit snake tube are connected.

  As shown in FIG. 6, engagement convex portions 52 are provided on a metal serpentine tube 50 in which a plurality of slits 51 are alternately formed in the longitudinal direction in the circumferential direction, and the engagement convex portions 52 are formed on the transparent resin cover 10. It is good also as a structure engaged with the engagement recessed part 13. FIG.

  As described in the above embodiment, the insertion portion 2 of the endoscope 1 is generally provided with a blade 25 so that high torque can be transmitted.

  By using the serpentine tube 50 in which the plurality of slits 51 are formed, the insertion portion 2 can be transmitted with high torque without providing the blade 25.

  Therefore, the insertion portion 2 of the endoscope 1 does not require the base 30 and the blade 25, and in particular, prevents the connecting portion of the blade 25 that is laminated on the stepped portion 31 of the base 30 and joined by soldering or welding from becoming thick. be able to. As a result, the insertion portion 2 can be further reduced in diameter. Furthermore, the hard length of the tip 3 can be shortened.

  When the serpentine tube 50 is formed of a superelastic metal such as nickel titanium, the engagement convex portion 52 is made into the engagement concave portion of the transparent resin cover 10 as shown in FIGS. When engaging with 13, the engagement protrusion 52 can be returned to its original state and engaged with the engagement recess 13 by bending outward and applying heat treatment.

  Further, although not shown in the drawing, the insertion portion 2 can be made extremely thin by a semi-rigid serpentine tube formed of a superelastic metal that does not have a plurality of slits 51. Moreover, it is good also as a rigid endoscope provided with the very thin insertion part 2 by using a hard pipe for a snake pipe and making the exterior resin pipe 26 into a metal pipe.

(Third Modification)
FIG. 9 is a side view showing a state where the transparent resin cover and the base of the third modification are connected, and FIG. 10 is a side view showing a state where the transparent resin cover and the base of the third modification are connected. .

  By the way, as described above, when the transparent resin cover 10 and the base 30 are assembled, the lens frame 23 holding the observation optical system 20, which is an internal component of the insertion portion 2, the image guide 22, and the light guide fiber 24 are inserted. In some cases, these built-in objects may be caught at the connecting portion between the transparent resin cover 10 and the base 30, or it may be difficult to fill a sufficient adhesive around the built-in objects.

  Therefore, as shown in FIGS. 9 and 10, a hook portion 14 having a substantially arrow shape extending from the base end of the step portion 11 of the transparent resin cover 10 is provided, and the hook portion 14 is fitted. It is also possible to form a locking recess 33 having a substantially arrow shape to be locked in the base 30 and mechanically join the transparent resin cover 10 and the base 30 by a so-called snap fit.

  Note that slits 34 are formed on both sides of the locking recess 33 of the base 30 so as to be elastically deformed so that the locking recess 33 can easily spread.

  As described above, the transparent resin cover 10 and the base 30 are joined by a so-called snap fit so that the lens frame 23, the image guide 22, and the light guide fiber that hold the observation optical system 20 that is built-in of the insertion portion 2. The transparent resin cover 10 can be connected to the base 30 in a state where 24 is attached to the base 30 in advance.

  As a result, the transparent resin cover 10 can be joined to the base 30 while checking the built-in object, and the adhesive 2 can be securely applied and filled around the built-in object, so that the insertion portion 2 of the endoscope 1 can be more easily performed. Watertightness can be ensured.

(Fourth modification)
FIG. 11 is a side view showing a state where the transparent resin cover and the base of the fourth modified example are connected, and FIG. 12 is a side view showing a state where the transparent resin cover and the base of the fourth modified example are connected. .

  As shown in FIGS. 11 and 12, the transparent resin cover 10 is provided with notches 15 and 35 in which a stepped portion 11 of the transparent resin cover 10 and a part of the side periphery of the base 30 are notched in a crank shape (U shape). It is good also as a structure which joins 10 to the nozzle | cap | die 30 from the direction orthogonal to an axial direction.

  Even in such a configuration, the transparent resin cover 10 is removed from the base 30 from the state in which the lens frame 23 that holds the observation optical system 20 that is built in the insertion portion 2, the image guide 22, and the light guide fiber 24 are previously projected from the base 30. It can connect to 30 and can further assemble a built-in thing by moving ahead.

  Even with such a configuration, the transparent resin cover 10 can be joined to the base 30 while checking the built-in components. In addition, the adhesive can be easily applied and filled around the built-in object.

(Fifth modification)
FIG. 13 is an exploded perspective view showing a connection configuration between a transparent resin cover and a base according to a fifth modification, and FIG. 14 is a side view showing a state where the transparent resin cover and the base according to the fifth modification are connected.

  As shown in FIGS. 13 and 14, a substantially T-shaped engagement recess 36 is also formed in the base 30 so that the substantially H-type engagement piece 16 is engaged with the transparent resin cover 10 and the base 30. The transparent resin cover 10 and the base 30 may be joined by engaging with a substantially H-shaped groove formed by the recesses 13 and 36.

  Even in such a configuration, the transparent resin cover 10 is attached to the base 30 in a state in which the lens frame 23 that holds the observation optical system 20 that is built-in of the insertion portion 2, the image guide 22, and the light guide fiber 24 are attached to the base 30 in advance. Therefore, the transparent resin cover 10 can be joined to the base 30 while checking the built-in object, and the adhesive can be securely applied and filled around the built-in object. Therefore, the insertion part 2 of the endoscope 1 can ensure watertightness more easily.

(Sixth Modification)
FIG. 15 is a partial cross-sectional view showing a state in which the transparent resin cover and the base of the sixth modified example are connected, and FIG. 16 is a cross-sectional view showing a state in which the transparent resin cover of the sixth modified example and the base are connected. is there.

  As shown in FIGS. 15 and 16, stepped portions 61 and 62 may be formed on the front and back of the base 60, and the transparent resin cover 10 may be insert-molded on the stepped portion 61 in front of the base 60.

  The step portion 61 on the front side of the base 60 is formed with one or a plurality of holes 63, and the resin of the transparent resin cover 10 enters the holes 63 to fill the holes 63. The transparent resin cover 10 is prevented from falling off from the base 60.

  That is, the resin that has entered the hole 63 becomes an anchor, and the transparent resin cover 10 is prevented from falling off from the base 60.

  Further, when the transparent resin cover 10 is insert-molded into the base 60, the step portion 11a shown in FIG. 16 shown by a dotted line by additional machining is formed, and the stepped portion 11 that covers the exterior resin tube 26 by adhesion or molding is formed. The water tightness is surely maintained and the diameter of the portion where the outer resin tube 26 is laminated is prevented from increasing.

  Further, by forming the step portion 11 of the transparent resin cover 10 and the step portion 61 of the base 60 so as to be laminated, the step portion 11 formed on the outer periphery of the step portion 61 of the metal base 60 is made thin. Can be processed. That is, the step portion 61 of the base 60 becomes an annular base portion that holds the transparent resin cover 10 by insert molding.

  Generally, the limit thickness of the resin molded product is about 0.1 mm, but since the processing is performed on the stepped portion 61 of the metal base 60, the stepped portion 11 of the transparent resin cover 10 is 0.1 mm. The wall thickness can be less than.

(Seventh Modification)
FIG. 17 is a cross-sectional view showing a state in which a transparent resin cover of another form according to the seventh modified example and a base are connected, and FIG. 18 is a side view showing the configuration of the base of another form according to the seventh modified example. is there.

As shown in FIGS. 17 and 18, a plurality of long hole portions 64 are formed in the step portion 61 on the front side of the base 60 to increase the volume of the resin in the transparent resin cover 10 during insert molding. Thus, the transparent resin cover 10 can be further prevented from falling off the base 30.
Further, since the thin range of the step portion 11 is reduced, the transparent resin cover 10 and the base 30 are more firmly fixed, and the strength against the torsional force from the outside can be secured.

(Eighth modification)
FIG. 19 is a partial cross-sectional view showing the configuration of the insertion portion where the transparent resin cover and the blade of the eighth modification are connected, and FIG. 20 shows the state where the transparent resin cover and the blade of the eighth modification are connected. It is a fragmentary sectional view.

  As shown in FIGS. 19 and 20, the base 30 is not provided, and the step 25 of the transparent resin cover 10 is covered with the blade 25. For example, the blade 25 is heated at a high frequency so that the step 11 is melted and embedded. It is also possible to adopt a configuration in which direct joining is performed.

  With such a configuration, the rigid length of the distal end portion 3 can be shortened, and the resin of the transparent resin cover 10 enters between the reticulated wires forming the blade 25, so that the transparent resin cover 10 can be removed. Can be prevented.

  Even if some constituent elements are deleted from all the constituent elements shown in the embodiment described above, if the stated problem can be solved and the stated effect can be obtained, The deleted configuration can be extracted as an invention.

DESCRIPTION OF SYMBOLS 1 ... Endoscope 2 ... Insertion part 10 ... Transparent resin cover 11 ... Step part 12 ... Opening part 13, 36 ... Engagement recessed part 14 ... Hook part 15, 35 ... Notch part 16 ... Engagement piece 20 ... Observation optical system DESCRIPTION OF SYMBOLS 21 ... Observation lens 22 ... Image guide 23 ... Lens frame 24 ... Light guide fiber 25 ... Blade 26 ... Outer resin tube 27 ... Inner resin tube 28 ... Outer shell 30 ... Base 31, 61, 62 ... Step part 32, 52 ... Engagement Projection 33 ... Locking recess 34 ... Slit 41 ... Illumination fiber 42 ... Actuator 50 ... Serpent tube 51 ... Slit 60 ... Base 63, 64 ... Hole

Claims (11)

An insertion portion to be inserted into the subject;
A cylindrical resin cover provided at the distal end of the insertion portion and having a stepped portion with a proximal end portion having a small diameter;
A first engaging portion provided within the outer diameter of the stepped portion;
A second engagement portion that engages with the first engagement portion within the outer diameter of the stepped portion and connects the resin cover so as not to move in the longitudinal axis direction of the insertion portion;
An outer tube that is connected so as to cover the stepped portion and covers a connecting portion formed by the first engaging portion and the second engaging portion;
An endoscope characterized by comprising:   The endoscope according to claim 1, further comprising an annular cap that is covered with the outer tube and provided with the second engaging portion. The first engagement portion is a concave groove formed in the base end portion of the stepped portion,
The endoscope according to claim 1, wherein the second engaging portion is a convex portion having a similar shape that engages with the groove portion. The first engaging portion is a hook portion extending from a base end portion to the stepped portion,
The endoscope according to claim 1, wherein the second engaging portion is a concave portion having a similar shape that locks the hook portion. The first engaging part is a first notch part formed in a part of a side periphery of the step part,
3. The inner portion according to claim 2, wherein the second engagement portion is a second notch portion that is formed in a part of a side periphery of the base and engages with the first notch portion. Endoscope. The first engaging portion is a concave groove formed in a base end portion of the stepped portion and a tip end portion of the base,
The endoscope according to claim 2, wherein the second engagement portion is an engagement piece similar to a shape formed by the groove portion of the stepped portion and the groove portion of the base. A metal tube that is covered with the outer tube and has a plurality of slits formed alternately in the circumferential direction in the circumferential direction,
The endoscope according to claim 1, wherein the second engagement portion is provided at a distal end of the metal tube. The base is formed with an annular base portion having a small diameter in the inner diameter direction provided with a hole at the tip portion,
The endoscope according to claim 2, wherein the resin of the resin cover is insert-molded so as to fill the hole so that the stepped portion is laminated on the base.   The endoscope according to claim 8, wherein a plurality of the long hole-shaped holes are formed in the base part.   The reticulated pipe is provided with a braided braided strand embedded in the stepped portion so that the resin covered with the outer tube and forming the resin cover enters between the reticulated strands. The endoscope according to Item 1. The resin cover is formed from a transparent resin,
An observation optical system provided in an opening formed in the center of the resin cover;
A light transmission member provided around the observation optical system;
The endoscope according to any one of claims 1 to 10, further comprising:

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