JP7156805B2 - Endoscope - Google Patents

Description

The present invention relates to endoscopes.

Endoscopes are used to observe the inside of living bodies or structures. An endoscope has a long insertion section for insertion into an observation target such as a living body or a building. The insertion portion is bent according to the internal shape of the observation object. After the distal end of the insertion section is inserted into the object to be observed, the user using the endoscope pushes the insertion section along the longitudinal direction, thereby further inserting the insertion section. For example, the insertion portion is inserted into the large intestine from the anus of the human body, and is inserted while bending according to the shape of the large intestine. For smooth observation, it is necessary to improve the insertability of the endoscope, that is, the ease of insertion. Patent Literature 1 discloses an example of a technique for improving insertability of an endoscope.

JP 2014-83293 A

An insertion portion of an endoscope may have a tendency to bend in one portion more easily than in other portions, or to bend easily in a particular direction but not in another direction. For example, when a heat load is applied while the insertion section is bent during transportation while it is packed in a case, or during cleaning, disinfection, or sterilization, the insertion section may become bent. An endoscope whose insertion portion has a tendency to bend is difficult to insert. For example, when a user pushes an insertion portion having a tendency to bend along the longitudinal direction, the insertion portion may bend at the portion having a tendency to bend, and the insertion portion may not move as intended by the user. In addition, when the user twists the insertion portion, which has a tendency to bend, in the lateral direction on the hand side, the twisting force may increase or decrease.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an endoscope in which the insertability of the insertion section is improved by making it difficult for the insertion section to bend. is to provide

An endoscope according to the present invention is an endoscope that includes a long insertion section for being inserted into an object to be observed, wherein the insertion section has a flexible soft section and has a linear shape. The flexible portion is linearly held by being sandwiched between a plurality of first holding posts arranged parallel to each other and a plurality of second holding posts parallel to the first holding posts. In the direction perpendicular to the longitudinal direction of the flexible portion from the opposite side of the first holding column with the flexible portion sandwiched at the middle position between the two first holding columns with a distance of 200 mm Three-point bending is performed by pushing the flexible part by 20 mm with the probe, and after holding the three-point bending state for 180 seconds, the probe and the flexible part when the probe is returned to the starting position of pushing. is the residual strain amount, and the soft portion has a region where the residual strain amount is 3 mm or more and 5 mm or less, and the region is 300 mm along the longitudinal direction from both ends of the soft portion It is characterized in that it occupies a range separated by more than

In the present invention, since the amount of residual strain remaining after the insertion portion is bent is small, the insertion portion is less prone to bending, and the insertability of the insertion portion is improved. Therefore, the present invention exhibits excellent effects such as obtaining an endoscope with an improved insertability of the insertion portion.

1 is an external view of an endoscope; FIG. It is an external view of the end surface of a front-end|tip part. FIG. 4 is a cross-sectional view of a flexible tube; FIG. 4 is an explanatory diagram for explaining a method of measuring residual strain amount; Fig. 10 is a graph schematically showing a temporal change in the amount of pressing of the probe into the flexible portion when measuring the amount of residual strain. 4 is a graph schematically showing the change over time of the pressing force measured by the load measuring device when measuring the amount of residual strain. FIG. 4 is a schematic diagram showing the positions of low-distortion regions; FIG. 5 is a chart showing the results of evaluating the insertability of the insertion portion for a plurality of soft portion samples having different amounts of residual strain. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings showing its embodiments.
FIG. 1 is an external view of an endoscope 10. FIG. For example, endoscope 10 is a flexible scope for the lower gastrointestinal tract. More specifically, the endoscope 10 is, for example, a colonoscope. The endoscope 10 has an insertion section 20 , an operation section 40 , a universal cord 59 and a connector section 50 . The insertion portion 20 is a portion that is inserted into the human body. The operation unit 40 is a portion that is held and operated by an operator who operates the endoscope 10 . The operating portion 40 has a curved knob 41 and a channel inlet 42 . A forceps plug 43 having an insertion opening for inserting a treatment instrument or the like is fixed to the channel entrance 42 .

The insertion portion 20 has an elongated tubular shape, and the end opposite to the distal end (the other end) is connected to the operation portion 40 . An anti-bending portion 24 is provided at the boundary between the insertion portion 20 and the operation portion 40 . The insertion section 20 has a flexible section 21 , a bending section 22 and a tip section 23 in order from the operation section 40 side. The soft portion 21 is soft and flexible. Since the flexible portion 21 has flexibility, the insertion portion 20 can be bent according to the internal shape of the observation object when the insertion portion 20 is inserted into the observation object. The surface of the soft portion 21 is a tubular flexible tube 30 which will be described later. The bending portion 22 bends according to the operation of the bending knob 41 . For example, the total length of the insertion portion 20 is 1400 mm or more.

In the following description, the side closer to the operating section 40 along the longitudinal direction of the insertion section 20 is referred to as the operating section side, and the side farther from the operating section 40 is referred to as the distal end side. The longitudinal direction of the insertion section 20 matches the insertion direction in which the insertion section 20 is inserted into the observation target. The universal cord 59 is long and has one end connected to the operating section 40 and the other end connected to the connector section 50 . Universal cord 59 is flexible. The connector section 50 is connected to a video processor, a light source device, a display device, an air/water supply device, and the like, which are not shown.

FIG. 2 is an external view of the end face of the tip portion 23. As shown in FIG. An observation window 51, two illumination windows 52, an air supply nozzle 53, a water supply nozzle 54, a channel outlet 55, and the like are provided on the end surface of the tip portion 23. As shown in FIG. The end surface of the tip portion 23 is substantially circular. The observation window 51 is provided above the center of the end face in FIG. Illumination windows 52 are provided on the left and right sides of the observation window 51 . An air-supply nozzle 53 and a water-supply nozzle 54 are provided at the lower right of the observation window 51 with their outlets facing the observation window 51 . A channel exit 55 is provided at the lower left of the observation window 51 .

Inside the connector portion 50, the universal cord 59, the operation portion 40, and the insertion portion 20, a fiber bundle for guiding light, a cable bundle for transmitting signals, an air supply tube, a water supply tube, and the like are inserted. Illumination light emitted from the light source device is irradiated from the illumination window 52 via the fiber bundle. The range illuminated by the illumination light is photographed by an imaging device (not shown) through the observation window 51 . A video signal is transmitted from the imaging device to the video processor through the cable bundle.

The air supplied from the air/water supply device is discharged from the air supply nozzle 53 toward the observation window 51 via the air supply tube. Similarly, water supplied from the air/water supply device is discharged from the water supply nozzle 54 toward the observation window 51 via the water supply tube. The air nozzle 53 and the water nozzle 54 are used for cleaning the observation window 51 during use of the endoscope. The channel inlet 42 and the channel outlet 55 are connected by a tubular channel passing through the inside of the flexible portion 21 and the curved portion 22 . By inserting a treatment instrument (not shown) from the channel inlet 42, the distal end of the treatment instrument can be protruded from the channel outlet 55 to perform procedures such as excision of large intestine polyps.

FIG. 3 is a cross-sectional view of the flexible tube 30. As shown in FIG. The flexible tube 30 is an exterior member for the flexible portion 21 . FIG. 3 shows a cross section of the flexible tube 30 cut along the longitudinal direction of the insertion section 20. As shown in FIG. The flexible tube 30 is constructed by sequentially covering the outside of a helical tube 31 formed by spirally winding a strip of metal with a mesh tube 32 , a skin 33 and a topcoat 34 . The helical tube 31 protects internal objects such as fiber bundles, cable bundles and various tubes inserted inside from being crushed when the flexible portion 21 is bent. The flexible tube 30 may be configured using a plurality of connected joint pieces instead of the helical tube 31 .

The reticular tube 32 is formed by braiding fine filamentary materials. The thin wire material is, for example, a stainless steel wire or a copper alloy wire. The thin wire material may be non-metallic. The skin 33 is a resin layer formed on the outside of the mesh tube 32 . The material of the outer skin 33 includes, for example, polyolefins such as ethylene-vinyl acetate copolymer, fluorine-based resins such as polytetrafluoroethylene and ethylene-tetrafluoroethylene copolymer, polyester-based elastomers, polyolefin-based elastomers, fluorine-based elastomers, Polyurethane-based elastomer, polyamide-based elastomer, silicone rubber, fluororubber, or the like. The outer skin 33 may be a laminate of a plurality of resin layers. A plurality of resin materials may be mixed to form the outer skin 33 . The material of the top coat 34 is, for example, urethane-based resin or fluororesin. The topcoat 34 protects the outer skin 33 from chemicals used for cleaning and disinfecting the endoscope 10 .

In this embodiment, the flexible portion 21 includes a region having a residual strain amount of 5 mm or less after bending. The definition and measurement method of the residual strain amount will be explained. FIG. 4 is an explanatory diagram for explaining a method of measuring the amount of residual strain. FIG. 4 is a top view of the three-point bending tester 60. As shown in FIG. The three-point bending tester 60 includes four holding columns 63 , two holding columns 64 , a load measuring device 61 and a drive section 65 . The load measuring device 61 is a measuring device that measures the load applied to the probe 62 protruding from one surface. The drive unit 65 is a mechanism that moves the load measuring device 61 .

The pressing columns 63 and 64 are cylindrical and arranged substantially parallel to each other. The four pressing columns 63 are arranged linearly. The distance between the central axes of the two pressing columns 63 located on the central side is 200 mm. The two pressing columns 64 are arranged at positions facing the four pressing columns 63 . The flexible portion 21 is linearly arranged along the row of the pressing columns 63 . The pressing column 63 contacts the side surface of the flexible portion 21 . The hold down post 64 contacts the opposite side surface. The flexible portion 21 is sandwiched and held between the pressing column 63 and the pressing column 64 . At an intermediate position between the two pressing columns 63 located on the central side, the probe 62 is brought into contact with the flexible portion 21 from the opposite side of the pressing column 63 so as to be orthogonal to the longitudinal direction of the flexible portion 21 . be.

When measuring the amount of residual strain, the driving section 65 moves the load measuring device 61 in a direction orthogonal to the longitudinal direction of the flexible section 21 . As a result, the flexible portion 21 is pushed by the tracing stylus 62 in a direction crossing the longitudinal direction. As indicated by the two-dot chain line in FIG. 4, the flexible portion 21 is in a three-point bending state in which it is bent at three points, that is, the two pressing columns 63 and the stylus 62 located on the central side. In this embodiment, as shown in FIG. 4, the probe 62 pushes the flexible portion 21 by 20 mm in a direction orthogonal to the longitudinal direction. After holding the state of being pushed by 20 mm for 180 seconds, the drive unit 65 moves the load measuring device 61 so as to return the position of the load measuring device 61 to the original position where the movement was started. The movement of the load measuring device 61 ends when the load measuring device 61 returns to its original position. When residual strain is generated by three-point bending, the shape of the flexible portion 21 does not completely return to a straight shape. The load measuring device 61 continues to measure the pressing force with which the tracing stylus 62 presses the flexible portion 21 . The pressing force measured by the load measuring device 61 has the same value as the repulsive force of the flexible portion 21 .

FIG. 5 is a graph schematically showing a temporal change in the pushing amount of the probe 62 pushing the flexible portion 21 when measuring the residual strain amount. The horizontal axis indicates time, and the vertical axis indicates the pushing amount. Indentation is length. The tracing stylus 62 starts to move at the start of movement, and pushes the flexible portion 21 by the movement. The pushing amount is equivalent to the change in the position of the stylus 62 . The point at which the pushing amount reaches 20 mm is the holding start point. The stylus 62 is held in a state of 20 mm for 180 seconds from the start of holding to the end of holding. After the end of holding, the stylus 62 moves to return to its original position. The point in time when the tracing stylus 62 returns to its original position is the end of movement, and the tracing stylus 62 ends its movement at the end of movement.

FIG. 6 is a graph schematically showing the change over time of the pressing force measured by the load measuring device 61 when measuring the residual strain amount. The horizontal axis indicates time, and the vertical axis indicates pressing force. The unit of pressing force is N (Newton). The pressing force increases from the start of movement to the start of holding. The pressing force reaches the maximum value at the start of holding. The pressing force is attenuated while the pressing amount is maintained at 20 mm. That is, the repulsive force of the soft portion 21 is attenuated. By subtracting the pressing force at the end of holding from the pressing force (maximum value of the pressing force) at the start of holding, the attenuation amount of the repulsive force is calculated. Also, the attenuation rate of the repulsive force is calculated by dividing the attenuation amount of the repulsive force by the maximum value of the pressing force.

The pressing force decreases from the end of holding to the end of movement. The pressing force becomes a value sufficiently smaller than the maximum value before reaching the end of movement. That is, the repulsive force of the flexible portion 21 becomes sufficiently close to zero before the stylus 62 returns to its original position. In this embodiment, the position of the tracing stylus 62 when the pressing force measured by the load measuring device 61 is 0.1 N is defined as the elastic limit point. The distance from the elastic limit point to the original position of the probe 62 is defined as the residual strain amount. The amount of residual strain is calculated by multiplying the elapsed time from when the probe 62 reaches the elastic limit point to when the movement ends, and the moving speed of the probe 62 . The moving speed of the tracing stylus 62 is, for example, 3.2 mm/s.

As described above, in this embodiment, the flexible portion 21 includes a low-strain region having a residual strain amount of 5 mm or less. FIG. 7 is a schematic diagram showing the position of the low-distortion region 211. As shown in FIG. As shown in FIG. 7, the low-strain region 211 is included in the flexible portion 21 and occupies a range separated from both ends of the flexible portion 21 by 300 mm or more along the longitudinal direction. That is, the low-strain region 211 is a region of the flexible portion 21 that is 300 mm or more away from the curved portion 22 along the longitudinal direction and 300 mm or more away from the anti-folding portion 24 . The area closer than 300 mm to the curved portion 22 along the longitudinal direction in the flexible portion 21 is the end portion of the flexible portion 21, and it is difficult or impossible to measure the amount of residual strain with the three-point bending tester 60. , are not included in the low distortion region 211 . In addition, the region of the flexible portion 21 that is closer than 300 mm to the anti-folding portion 24 along the longitudinal direction is close to the operation portion 40 and is not inserted deep into the observation object, so that it does not affect the insertability. hard.

A plurality of samples of the flexible portion 21 having different amounts of residual strain in the low strain region 211 were prepared, and an experiment was conducted to evaluate the insertability of each sample. FIG. 8 is a chart showing the results of evaluating the insertability of the insertion portion 20 for a plurality of soft portion 21 samples having different amounts of residual strain. Samples A to I, which are samples of the flexible portion 21 having different configurations of the flexible tube 30, were prepared, and the residual strain amount and the damping rate of the repulsive force were measured for each sample. The residual strain amount and repulsive force damping rate of each sample shown in FIG. 8 are averages of values measured at multiple points in the longitudinal direction. FIG. 8 also shows the parameters of the flexible tube 30 constituting each sample. As parameters, the difference between whether the flexible tube 30 uses the helical tube 31 or the joint piece, the residual strain of the outer skin 33, the thickness of the topcoat 34, and the flexibility of the flexible tube 30 are shown. there is

The residual strain of the skin 33 is the strain that occurs after the skin 33 is stretched. The residual strain of the outer skin 33 is measured using a precision universal tester. For example, for the measurement, a dumbbell-shaped No. 3 test piece specified in JIS (Japan Industrial Standard) K6251 "Vulcanized rubber and thermoplastic rubber-Determination of tensile properties" is used. A test piece can be produced by molding the resin material used for the outer skin 33 into a thin plate having a predetermined thickness and punching it out with a predetermined punching blade. Since the aforementioned JIS standard does not specify a method for measuring residual strain, the outline of the method for measuring is described below. For the measurement, the same precision universal tester and grips as specified in the JIS standard can be used.

A specimen of outer skin 33 is attached to a precision universal tester. The distance between the grips of the precision universal tester is set to 50 mm. The grips are pulled apart at a speed of 20 mm/s to stretch the test piece by 5 mm. Hold the stretched position for 180 seconds. After that, the gripper is returned to its original position at a speed of 20 mm/s, and the test piece is removed from the gripper. The residual strain is calculated by dividing the amount of elongation of the removed specimen by the distance extended during the test (5 mm in this example).

FIG. 8 shows the flexibility of the flexible tube 30 at a position of 300 mm from the distal end of the distal end portion 23 and a position of 1000 mm from the distal end of the distal end portion 23 . It also shows the average flexibility for multiple locations in the longitudinal direction. Flexibility is indicated in three stages: soft, medium, and hard. As shown in FIG. 8, the smaller the residual strain of the outer skin 33 and the smaller the thickness of the topcoat 34, the softer the flexibility. Also, when the flexible tube 30 uses a joint piece, the flexibility is harder than when the helical tube 31 is used.

FIG. 8 also shows the insertability of the insertion portion 20 evaluated for each sample. Insertability is indicated with 1 being best, 2 being good, and 3 being bad. Samples A to D all have a residual strain amount of 5 mm or less in the low strain region 211, and the insertability of the insertion portion 20 is the best. Since the insertability of the insertion portion 20 was the best, it is desirable that the amount of residual strain in the low-strain region 211 is 5 mm or less. A small amount of residual strain indicates that the flexible portion 21 returns to a more linear shape even after the flexible portion 21 is bent. Even when the flexible section 21 is bent, such as when the endoscope 10 is stored with the insertion section 20 bent, the flexible section 21 is less prone to bending.

Also, the amount of residual strain in the low-strain region 211 and the damping rate of the repulsive force are correlated. As the residual strain amount decreases, the damping rate of the repulsive force also decreases. If the damping rate of the repulsive force is too low, the repulsive force becomes too strong, the flexibility of the flexible portion 21 decreases, and the insertability of the insertion portion 20 deteriorates. Specifically, when the damping rate of the repulsive force is less than 15%, the repulsive force becomes too strong and the flexibility of the flexible portion 21 decreases. When the residual strain amount of the low-strain region 211 is less than 3 mm, the damping rate of the repulsive force is less than 15%. Therefore, it is desirable that the residual strain amount of the low-strain region 211 is 3 mm or more and the damping rate of the repulsive force is 15% or more.

The amount of residual strain in the low-strain region 211 and the damping rate of the repulsive force change depending on the configuration of the flexible tube 30 . The smaller the residual strain of the outer skin 33 and the smaller the thickness of the top coat 34 , the lower the residual strain amount and the damping rate of the repulsive force of the low-strain region 211 . In particular, when the residual strain of the outer skin 33 is 18-22% and the thickness of the topcoat 34 is 10-30 μm, as shown for samples A and B, the residual strain amount of the low strain region 211 is 3.0 μm. 5 to 4 mm, and the damping rate of the repulsive force is 15 to 20%, and the insertability of the insertion portion 20 is the best.

Further, comparing sample D and sample E, when the flexible tube 30 uses a joint piece, the amount of residual strain in the low-strain region 211 is lower than when the helical tube 31 is used. That is, in order to improve the insertability of the insertion portion 20, it is more preferable that the flexible tube 30 uses a joint piece.

Samples E and F have good insertability of the insertion portion 20 . As shown for samples E and F, even if the residual strain amount of the low strain region 211 slightly exceeds 5 mm, if the repulsive force attenuation rate is 20 to 30%, the insertion of the insertion portion 20 good properties. Therefore, it is desirable that the damping rate of the repulsive force is 30% or less. Also, as shown for samples E and F, when the residual strain of the outer skin 33 is 27% and the thickness of the topcoat 34 is 30-60 μm, the residual strain amount of the low-strain region 211 is 6-7 mm. Even if there is, the damping rate of the repulsive force is 20 to 30%. That is, in order to make the damping rate of the repulsive force 30% or less and improve the insertability of the insertion portion 20, the residual strain of the outer skin 33 should be 27% or less and the thickness of the topcoat 34 should be 60 μm or less. desirable.

Samples G to I all have a residual strain amount of 7.5 mm or more in the low strain region 211 and a repulsive force attenuation rate of 30% or more, and the insertability of the insertion portion 20 is poor. In samples G-I, the residual strain of the skin 33 is 29% or the thickness of the topcoat 34 is 60-120 μm. In the insertion portion 20 using the flexible tube 30 with a large residual strain of the outer skin 33 or a large thickness of the top coat 34, the residual strain amount and the attenuation rate of the repulsive force in the low strain region 211 are large, resulting in poor insertability. .

As described in detail above, in the present embodiment, the residual strain amount of the low-strain region 211 included in the flexible portion 21 is 5 mm or less, and more preferably 3 mm or more and 5 mm or less. Since the amount of residual strain is small, it is difficult for the flexible portion 21 to develop a tendency to bend. For example, even if a heat load is applied while the insertion portion is bent during transportation when it is packed in a case, or during cleaning, disinfection, or sterilization, the flexible portion 21 is less prone to bending. . Since the flexible portion 21 is less prone to bending, bending of the flexible portion 21 in directions unintended by the user during use of the endoscope 10 is suppressed, and the insertability of the insertion portion 20 is improved. For example, when the user pushes the insertion section 20 along the longitudinal direction, the flexible section 21 is suppressed from bending in a direction unintended by the user at the portion with a tendency to bend, and the insertion section 20 is pushed in by the user. It becomes easier to move as intended. Also, even when the user twists the insertion portion 20 in the lateral direction, the twisting force does not increase or decrease, which improves handling. In this manner, handling of the insertion section 20 by the user when using the endoscope 10 is improved, and insertability of the insertion section 20 is improved. Therefore, in the present embodiment, the endoscope 10 with improved insertability of the insertion portion 20 can be obtained.

In this embodiment, illumination light is obtained from a light source device (not shown). There may be. Further, in the present embodiment, an example was shown in which the position of the probe 62 when the pressing force becomes 0.1 N when measuring the amount of residual strain is set as the elastic limit point. A value other than 0.1N may be used as the threshold for determining that the pressing force corresponding to has become sufficiently close to zero.

The present invention is not limited to the contents of the above-described embodiments, and various modifications are possible within the scope of the claims. That is, the technical scope of the present invention also includes embodiments obtained by combining technical means appropriately modified within the scope of the claims.

10 Endoscope 20 Insertion Section 21 Flexible Section 211 Low Strain Area 22 Bending Section 23 Tip Section 24 Bending Stop Section 30 Flexible Tube 40 Operation Section 50 Connector Section 59 Universal Cord 60 Three-Point Bending Tester 61 Load Measuring Device 62 Probe 63 Hold-down column

Claims (2)

An endoscope having a long insertion section for insertion into an observation object,
The insertion section has a flexible soft section,
The flexible portion is linearly held by being sandwiched between a plurality of linearly arranged first pressing columns parallel to each other and a plurality of second pressing columns parallel to the first pressing columns. , and the distance between them is 200 mm. Three-point bending is performed by pushing the flexible portion 20 mm in the direction with the probe, and after holding the state in which the three-point bending is performed for 180 seconds, the probe is returned to the starting position of pushing. The distance between the flexible part is the amount of residual strain, and the flexible part has a region where the amount of residual strain is 3 mm or more and 5 mm or less ,
The region occupies a range separated by 300 mm or more along the longitudinal direction from both ends of the flexible portion.
An endoscope characterized by: 2. The endoscope according to claim 1 , wherein, in said region, an attenuation rate at which the repulsive force is attenuated when said three-point bending is continued for 180 seconds is 15% or more and 30% or less.

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