Advance and retreat assisting tool for treatment instrument and endoscope system

An advance and retreat assisting tool for a treatment instrument includes: a base; an attaching portion; a first cylinder which is attached to the base; a second cylinder which has a fixing portion fixing the treatment instrument and slides in an advance and retreat direction with respect to the first cylinder along a center axis of the first cylinder; an advance and retreat mechanism which advances and retreats the second cylinder along the center axis with respect to the first cylinder by rotation; and an assisting portion which urges the second cylinder in a predetermined direction along the center axis with respect to the base with an urging force smaller than a resistance force when the second cylinder slides and assists the rotation of the advance and retreat mechanism when the advance and retreat mechanism rotates in one direction.

FIELD

The present invention relates to an advance and retreat assisting tool for a treatment instrument for advancing and retreating the treatment instrument.

BACKGROUND

For example, Patent Literature 1 discloses an advance and retreat assisting tool for a treatment instrument passing through an endoscope.

CITATION LIST

Patent Literature

SUMMARY

An advance and retreat assisting tool for a treatment instrument according to an aspect of the present invention includes: a base which has a through-hole; an attaching portion which attaches the base to an endoscope such that the through-hole faces a treatment instrument insertion port of the endoscope; a first cylinder which is attached to the base such that an inner portion thereof is in communication with the through-hole; a second cylinder which has a fixing portion fixing the treatment instrument inserted into the treatment instrument insertion port and slides in an advance and retreat direction with respect to the first cylinder along a center axis of the first cylinder; an advance and retreat mechanism which advances and retreats the second cylinder along the center axis with respect to the first cylinder by rotation; and an assisting portion which urges the second cylinder in a predetermined direction along the center axis with respect to the base with an urging force smaller than a resistance force when the second cylinder slides and assists the rotation of the advance and retreat mechanism when the advance and retreat mechanism rotates in one direction.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. An endoscope of an endoscope system to be described below is inserted into and used in a hole (body cavity) of a medical examinee (subject). An advance and retreat assisting tool14(advance and retreat assisting tool for a treatment instrument) applied to an endoscope system11is used to finely adjust a position, in a longitudinal direction, of a treatment instrument13passing through the inside of a treatment instrument insertion channel26of the endoscope, and can finely adjust the position of the treatment instrument13in the longitudinal direction by a user's operation.

First Embodiment

An endoscope system11according to a first embodiment will be described with reference toFIGS. 1 to 6. As shown inFIG. 1, the endoscope system11includes an endoscope12, a treatment instrument13passing through the inside of the endoscope12, an advance and retreat assisting tool14attached to the endoscope12, an endoscope controller15(image processing portion) performing image processing based on an image of an object captured by the endoscope12, and a display portion16(monitor) displaying a video generated by the image processing in the endoscope controller15.

As shown inFIG. 1, the endoscope12(insertion device) includes an insertion portion17inserted into a duct such as a lumen of a subject in a longitudinal direction L, an operation portion18provided at a proximal end of the insertion portion17and grasped by a user, a universal cord21extending from the operation portion18, and a distal end constituting portion22provided on a distal end side of the insertion portion17and being rigid.

As shown inFIG. 1, the insertion portion17defines the longitudinal direction L by a distal end and a proximal end thereof. As shown inFIG. 1, the insertion portion17includes the distal end constituting portion22, a bending portion23, and a tube portion24in order from the distal end thereof toward the proximal end thereof. The tube portion24has flexibility. The bending portion23can bend the distal end constituting portion22in a plurality of directions (for example, four directions toward the top, bottom, left, and right) by a knob25of the operation portion18by a known mechanism.

As shown inFIG. 1, the endoscope12has an illumination optical system, an observation optical system, and a treatment instrument insertion channel26. In addition, the endoscope has an air/water supply mechanism and a suction mechanism. The air/water supply mechanism has a nozzle at a distal end thereof, and is operated by a first button27of the operation portion18. The suction mechanism is in communication with the treatment instrument insertion channel26, and is operated by a second button28of the operation portion18.

The illumination optical system and the observation optical system are inserted into the distal end constituting portion22, the bending portion23, and the tube portion24of the insertion portion17, the operation portion18, and the universal cord21of the endoscope12. The illumination optical system has an illumination window at the distal end constituting portion22. The observation optical system has an observation window at the distal end constituting portion.

A distal end of the treatment instrument insertion channel26is opened in the distal end constituting portion22, and a proximal end of the treatment instrument insertion channel26is opened in the vicinity of a proximal end portion of the tube portion24or the operation portion18. For example, it is possible to allow the treatment instrument13capable of incising and excising a living tissue of the affected part to pass through the inside of the treatment instrument insertion channel26. Here, as shown inFIG. 1, a treatment instrument insertion port31positioned at the proximal end of the treatment instrument insertion channel26is provided in the operation portion18, and a forcep plug32(seeFIG. 23) is attachable to and detachable from the treatment instrument insertion port31. The treatment instrument insertion channel26is branched into, for example, a known suction path inside the operation portion18. The suction path is connected to the second button28. An aspirate is discharged from an aperture (to be described below) of the distal end of the treatment instrument insertion channel26through a mouthpiece, a tube, the suction path, and the universal cord21by a pressing operation of the second button28.

The treatment instrument13is a conventional treatment instrument (surgical instrument) passing through the inside of the treatment instrument insertion channel26of the endoscope12. The treatment instrument13can approach the affected part and perform an incision and excision on the living tissue of the affected part, in a field of view of the endoscope12.

The advance and retreat assisting tool14can advance and retreat the treatment instrument13passing through the inside of the treatment instrument insertion channel26of the endoscope12in the direction along the longitudinal direction (direction of a center axis C). As shown inFIGS. 1 to 3, the advance and retreat assisting tool14includes a base33attached to the operation portion18, an attaching portion34attaching the base33to the endoscope12such that a through-hole33A of the base33faces the treatment instrument insertion port31of the endoscope12, a first cylinder35attached to the base33, a second cylinder36sliding in an advance and retreat direction with respect to the first cylinder35along the center axis C of the first cylinder35, an advance and retreat mechanism37advancing and retreating the second cylinder36along the center axis C with respect to the first cylinder35, an assisting portion38assisting rotation of the advance and retreat mechanism37when the advance and retreat mechanism37rotates in one direction, and a positioning portion41positioning the second cylinder36at a predetermined position with respect to the base33. The first cylinder35, the second cylinder36, the advance and retreat mechanism37, and the assisting portion38constitute a moving unit42for advancing and retreating the treatment instrument13. The attaching portion34may be provided at one position or at a plurality of positions. In addition, it is preferable that a shape of the attaching portion34is a belt-like shape.

The base33has the through-hole33A through which the treatment instrument13passes (seeFIG. 5). The base33can cover, for example, the forcep plug32from an upper side (seeFIG. 23and the like).

As shown inFIGS. 2 and 5, the first cylinder35is attached to the base33such that an inner portion thereof is in communication with the through-hole33A. The first cylinder35has a first main body43having a cylindrical shape and a first arm portion44extending from a part of the first main body43facing the base33. A dial45of the advance and retreat mechanism37is rotatably attached to a distal end of the first arm portion44. The first main body43and the first arm portion44are molded integrally with each other by, for example, a synthetic resin material. As shown inFIG. 3, the first cylinder35has a groove portion46extending along an extending direction (the center axis D of the first cylinder35) of the treatment instrument13. A pin47of the second cylinder36to be described below slidably passes through the inside of the groove portion46. The center axis D of the first cylinder35coincides with the center axis C of the treatment instrument13.

The second cylinder36has a second main body51having a tubular shape, a holding member53protruding from a distal end side opposite to a side of the second main body51facing the base33in a radial direction of the second main body51and having a disk shape, a fixing portion54attachable to and detachable from the second main body51and having a cap shape, and a fastening portion59provided inside the fixing portion54, compressed when the fixing portion54is fastened to the second main body51to allow the treatment instrument to be fixed thereto, and having elasticity. The fastening portion59is formed in an annular shape by, for example, elastic rubber. The treatment instrument13can pass through a hole portion positioned at the center of the fastening portion59. The fixing portion54is fixed to the second main body51by, for example, screwing or the like, to elastically deform the fastening portion59, thereby allowing the fastening portion59to be closely adhered to the treatment instrument13. As a result, the fastening portion59engages with the treatment instrument13, and the treatment instrument13and the second cylinder36are fixed to each other. In addition, in a state where the fixing portion54is fixed to the second main body51, the fastening portion59also functions as a liquid-tight member hindering movement of a liquid between the inside and the outside of the second main body51to prevent a body fluid and the like from bleeding to the outside along the treatment instrument13. The second cylinder36can move with respect to the first cylinder35. A structure fixing the second cylinder36and the treatment instrument13to each other is not limited thereto. The fixing portion54may have a shape having a slit. The treatment instrument13may be inserted into the slit of the fixing portion54, so that the treatment instrument13and the second cylinder36are integrated with each other by frictional resistance.

As shown inFIGS. 2 and 3, the advance and retreat mechanism37includes the dial45, a rotation shaft55, and a cam mechanism56converting rotation of the dial45into advance and retreat of the second cylinder36(treatment instrument13). The dial45is provided so as to be rotatable around the rotation shaft55provided on the first arm portion44of the first cylinder35. The rotation shaft55extends in a direction along the extending direction (direction of the center axis C) of the treatment instrument13. The cam mechanism56includes a cam groove57formed in a spiral shape on an outer circumferential surface of the dial45and a pin47formed in the second cylinder36so as to protrude from the second main body51. For this reason, the dial45is rotated by user's fingers, so that the second cylinder36can protrude from the first cylinder35or the second cylinder36can be received in the first cylinder35, by an action of the cam mechanism56(the cam groove57and the pin47). The cam mechanism56is an example of a transfer portion converting a rotation force of the dial45into a force for advancing and retreating the second cylinder36in a direction along the center axis C of the first cylinder35. Therefore, the advance and retreat mechanism37can advance and retreat the treatment instrument13by rotating the dial45with the user's fingers. That is, when viewed from an opposite side to the base33, for example, when the dial45is rotated counterclockwise, the pin47is moved toward the opposite side to the base33by an action of the cam groove57. Likewise, when viewed from the opposite side to the base33, for example, when the dial45is rotated clockwise, the pin47is moved toward the base33by an action of the cam groove57.

As shown inFIGS. 3 and 4, the positioning portion41includes a pair of convex portions58protruding into the groove portion46of the first cylinder35. Each of the convex portions58is formed in a “wedge shape” protruding so as to approach the center axis D of the groove as the distance to an end portion46B on an opposite side to a bottom portion46A of the groove portion46is decreased. As shown inFIG. 3, when the second cylinder36moves from a protruding position61at which it protrudes from the first cylinder35to a received position62at which it is received in the first cylinder35, the pin47has a structure in which it is caught by the convex portions58. Therefore, a large resistance force is generated when the pin47passes between the convex portions58. As a result, the positioning portion41prevents the second cylinder36from being moved from the protruding position61to the received position62when the user does not intend this movement. For this reason, it is difficult for the second cylinder36to move from the protruding position61to the received position62, but since a restoring force of a tension spring of the assisting portion38acts on the movement of the second cylinder36in this direction, there is no hindrance to an advance and retreat operation of the treatment instrument13.

On the other hand, as shown inFIGS. 3 and 4, when the second cylinder36moves from the received position62at which it is received in the first cylinder35to the protruding position61at which it protrudes from the first cylinder35, the positioning portion41described above has the “wedge shape”, so that it is difficult for the pin47to be caught by the convex portions58. Therefore, a large resistance force is not generated when the pin47passes between the convex portions58. For this reason, since the resistance force at the time of the movement is smaller than that when the second cylinder36moves from the protruding position61to the received position62, a load applied to the user's fingers when moving the second cylinder36from the received position62to the protruding position61is reduced. On the other hand, since a predetermined frictional force acts when the pin47passes between the convex portions58, the positioning portion41prevents the second cylinder36from being moved from the received position62to the protruding position61when the user does not intend this movement.

As shown inFIG. 2, the assisting portion38is formed of a member having elasticity, for example, a tension spring (preferably, a tension coil spring) spanned between the base33and the holding member53of the second cylinder36. An end portion of the assisting portion38adjacent to the base33is fixed to the base33through a fixing member65(screw) fixed to the base33. An end portion of the assisting portion38on the opposite side to the base33is fixed to the base33through the holding member53(a locking hole53A formed in the holding member53) fixed to the second cylinder36and having the disk shape. The assisting portion38may be spanned between the first cylinder35and the second cylinder36. The assisting portion38is disposed outside the first cylinder35.

Next, an effect of the present embodiment will be described with reference toFIGS. 5 to 7and the like.

The endoscope12according to the present embodiment is designed such that the operation portion18is grasped with the left hand and the insertion portion17is grasped with the right hand, as shown inFIG. 1. As shown inFIG. 1, the treatment instrument13passes through the treatment instrument insertion channel26of the endoscope12. In a state where the operation portion18is grasped with the left hand as described above, for example, when the user wants to further protrude the treatment instrument13from the endoscope12to advance the treatment instrument13, the user moves fingers64in a direction in which the fingers64become distant from a palm surface63to rotate the dial45in a clockwise direction when viewed from the opposite side to the base33. As a result, the pin47and the second cylinder36are moved toward the treatment instrument insertion port31(base33) by an action of the cam groove57. In this case, as shown inFIG. 5, the restoring force of the tension spring of the assisting portion38acts to urge the second cylinder36toward the base33, thereby assisting the movement of the second cylinder36. Therefore, a force for rotating the dial45in the clockwise direction is reduced. As a result, even in a case where the user moves the fingers64in the direction in which the fingers64becomes distant from the palm surface63, which is a direction in which it is ergonomically difficult to apply the force, the rotation of the dial45and the advance of the treatment instrument13are assisted by an action of the assisting portion38. An urging force of the tension spring of the assisting portion38is smaller than a resistance force (frictional force) when the second cylinder36slides with respect to the first cylinder35. In this case, the resistance force when the second cylinder36slides includes at least one of a frictional force between the first cylinder35and the second cylinder36and a frictional force applied when the advance and retreat mechanism (dial) advances or retreats the second cylinder36.

On the other hand, when the user wants to retreat the treatment instrument13so as to return the treatment instrument13toward the endoscope12, the user moves the fingers64in a direction in which the fingers64approach the palm surface63to rotate the dial45in a counterclockwise direction when viewed from the opposite side to the base33. As a result, the pin47and the second cylinder36are moved toward an opposite side (protruding position61) to the treatment instrument insertion port31by an action of the cam groove57. In this case, as shown inFIG. 6, the restoring force of the tension spring of the assisting portion38becomes resistance when moving the second cylinder36. However, since an operation of moving the fingers64in the direction in which the fingers64approach the palm surface63is an operation in which it is ergonomically easy to apply a force, the rotation of the dial45in the counterclockwise direction (retreat of the treatment instrument13) is hardly hindered. In this example, the movement between the protruding position61and the received position62has been described by way of example, but the same effect is also achieved in the movement at an intermediate position between the protruding position61and the received position62.

According to the first embodiment, the advance and retreat assisting tool14for a treatment instrument can be configured as follows. The advance and retreat assisting tool14for a treatment instrument includes the base33which has the through-hole33A, the attaching portion34which attaches the base33to the endoscope12such that the through-hole33A faces the treatment instrument insertion port31of the endoscope12, the first cylinder35which is attached to the base33such that the inner portion thereof is in communication with the through-hole33A, the second cylinder36which has the fixing portion54fixing the treatment instrument13inserted into the treatment instrument insertion port31and slides in the advance and retreat direction with respect to the first cylinder35along the center axis C of the first cylinder35, the advance and retreat mechanism37which advances and retreats the second cylinder36along the center axis C with respect to the first cylinder35by rotation, and the assisting portion38which urges the second cylinder36in a predetermined direction along the center axis C with respect to the base33with the urging force smaller than the resistance force when the second cylinder36slides and assists the rotation of the advance and retreat mechanism37when the advance and retreat mechanism37rotates in one direction.

According to such a configuration, it is possible to easily perform the rotation of the advance and retreat mechanism37in one direction, so that the force required for the operation of the advance and retreat mechanism37is reduced, and it is thus possible to provide the advance and retreat assisting tool14for a treatment instrument in which operability is improved. In addition, since the assisting portion38urges the second cylinder36with the urging force smaller than the resistance force when the second cylinder36slides, it is possible to prevent a position of the treatment instrument13from being moved by the urging force of the assisting portion38when the user does not intend this movement.

The advance and retreat assisting tool for a treatment instrument13includes the positioning portion41which positions the urged second cylinder36at a predetermined position with respect to the base33. According to such a configuration, due to the positioning portion41, it is possible to prevent the second cylinder36from being moved when the user does not intend this movement. Therefore, it is possible to suppress the treatment instrument13from being freely moved, so that is possible to prevent a defect such as deviation of the treatment instrument13from the field of view of the endoscope12.

The positioning portion41defines a relative positional relationship between the first cylinder35and the second cylinder36in the direction of the center axis C. According to such a configuration, it is possible to determine the relative positional relationship between the first cylinder35and the second cylinder36by the positioning portion41, such that it is possible to prevent the defect such as the deviation of the treatment instrument13from the field of view of the endoscope12without the treatment instrument13being freely moved against intension of the user.

An outer diameter of the second cylinder36is smaller than an inner diameter of the first cylinder35, and the second cylinder36advances and retreats between a position in a state where it is inserted into the first cylinder35and a position in a state where it protrudes from the first cylinder35. According to such a configuration, it is possible to realize a configuration in which the second cylinder36moves with respect to the first cylinder35with a simple structure.

The advance and retreat mechanism37includes the dial45which rotates around the predetermined rotation shaft55by a force operated from the outside and the transfer portion which converts the rotation force of the dial45into the force for advancing and retreating the second cylinder36in the direction along the axis. According to such a configuration, it is possible to advance and retreat the treatment instrument13by a simple structure through the dial45and the transfer portion, so that it is possible to reduce a manufacturing cost by a reduction in the number of components.

In addition, according to the first embodiment, the advance and retreat assisting tool14for a treatment instrument can be configured as follows. The advance and retreat assisting tool14for a treatment instrument includes the first cylinder35, the second cylinder36which has the fixing portion54fixing the treatment instrument13inserted into the endoscope12and slides in an extending direction of the first cylinder35with respect to the first cylinder35, the advance and retreat mechanism37which causes the second cylinder36to slide in the extending direction of the first cylinder35by the rotation, and the assisting portion38which assists the rotation of the advance and retreat mechanism37when the advance and retreat mechanism37is rotated by moving the fingers64in the direction in which the fingers64become distant from the palm surface63. According to such a configuration, when the fingers64move in the direction in which it is ergonomically difficult to apply the force, it is possible to assist the rotation of the advance and retreat mechanism37by the assisting portion38. According to such a configuration, it is possible to realize the advance and retreat assisting tool14for a treatment instrument in which user's operability is improved.

In modified examples to be described below, parts different from those of the above embodiment will be mainly described, and illustration or description of parts common to those of the above embodiment will be omitted.

First Modified Example

FIG. 8shows a positioning portion41of an endoscope system11according to a first modified example. In the present modified example, a structure of the positioning portion41is different from that of the above embodiment.

As shown inFIG. 8, the positioning portion41includes a pair of convex portions58protruding into the groove portion46of the first cylinder35. Each of the convex portions58is formed in a “wedge shape” protruding so as to approach the center axis D of the groove as the distance to the bottom portion46A of the groove portion46is decreased. That is, in the first modified example, a direction of a tip of the wedge shape of the convex portion58is an opposite direction.

An operation of the endoscope system according to the first modified example will be described.

As shown inFIG. 8, when the second cylinder36(seeFIG. 3) moves from the protruding position61at which it protrudes from the first cylinder35to the received position62at which it is received in the first cylinder35, the positioning portion41described above has the “wedge shape”, so that it is difficult for the pin47to be caught by the convex portions58. Therefore, a large resistance force is not generated when the pin47passes between the convex portions58. On the other hand, since a predetermined frictional force acts when the pin47passes between the convex portions58, the positioning portion41prevents the second cylinder36from being moved from the protruding position61to the received position62when the user does not intend this movement. In addition, as the second cylinder36moves from the protruding position61to the received position62, the restoring force of the tension spring of the assisting portion38acts. Therefore, a load applied to the user's fingers when moving the second cylinder36from the protruding position61to the received position62is reduced.

On the other hand, when the second cylinder36moves from the received position62at which it is received in the first cylinder35to the protruding position61, a large resistance force is generated when moving the second cylinder36. For this reason, it is possible to prevent the second cylinder36from being moved from the received position62to the protruding position61when the user does not intend this movement. In this case, the movement of the second cylinder36from the received position62to the protruding position61corresponds to an operation of moving the fingers in the direction in which the fingers approach the palm surface63to rotate the dial45. For this reason, the rotation of the dial45in this direction is an operation in which it is ergonomically easy to apply a force, so that an advance and retreat operation of the treatment instrument13is not hindered.

Second Modified Example

FIG. 9shows a positioning portion41of an endoscope system11according to a second modified example. In the present modified example, a structure of the positioning portion41is different from those of the above embodiment and the above modified example.

As shown inFIG. 9, the positioning portion41includes a pair of convex portions58protruding into the groove portion46of the first cylinder35. Each of the convex portions58is formed in, for example, a “mountain shape of a normal distribution” or “bell shape”.

An operation of the endoscope system according to the second modified example will be described.

When the second cylinder36(seeFIG. 3) moves from the protruding position61at which it protrudes from the first cylinder35to the received position62at which it is received in the first cylinder35, a predetermined frictional force acts when the pin47passes between the convex portions58. For this reason, the positioning portion41prevents the second cylinder36from being moved from the protruding position61to the received position62when the user does not intend this movement. As the second cylinder36moves from the protruding position61to the received position62, the restoring force of the tension spring of the assisting portion38acts. For this reason, since the resistance force at the time of the movement is smaller than that when the second cylinder36moves from the received position62to the protruding position61, a load applied to the user's fingers when moving the second cylinder36from the protruding position61to the received position62is reduced.

On the other hand, when the second cylinder36moves from the received position62at which it is received in the first cylinder35to the protruding position61, the same resistance force as that when the second cylinder36moves from the protruding position61to the received position62is generated. For this reason, it is possible to prevent the second cylinder36from being moved from the received position62to the protruding position61when the user does not intend this movement. In this case, the movement of the second cylinder36from the received position62to the protruding position61corresponds to an operation of moving the fingers in the direction in which the fingers approach the palm surface63to rotate the dial45. For this reason, the rotation of the dial45in this direction is an operation in which it is ergonomically easy to apply a force, so that an advance and retreat operation of the treatment instrument13is not hindered.

Third Modified Example

FIG. 10shows a positioning portion41of an endoscope system11according to a third modified example. In the present modified example, a structure of the positioning portion41is different from those of the above embodiment and the above modified examples.

As shown inFIG. 10, the positioning portion41includes one convex portion58protruding into the groove portion46of the first cylinder35. The convex portion58has the same shape as that in the above embodiment, and is formed in a “wedge shape” protruding so as to approach the center axis D of the groove as the distance to the end portion46B on the opposite side to the bottom portion46A of the groove portion46is decreased.

An operation of the endoscope system11according to the third modified example will be described.

As shown inFIG. 10, when the second cylinder36(seeFIG. 3) moves from the protruding position61at which it protrudes from the first cylinder35to the received position62at which it is received in the first cylinder35, the pin47has a structure in which it is caught by the convex portions58. Therefore, a large resistance force is generated when the pin47passes between the convex portions58. As a result, the positioning portion41prevents the second cylinder36from being moved from the protruding position61to the received position62when the user does not intend this movement. For this reason, it is difficult for the second cylinder36to move from the protruding position61to the received position62, but since a restoring force of a tension spring of the assisting portion38acts on the movement of the second cylinder36in this direction, there is no hindrance to an advance and retreat operation of the treatment instrument13.

On the other hand, when the second cylinder36moves from the received position62at which it is received in the first cylinder35to the protruding position62at which it protrudes from the first cylinder35, the positioning portion41described above has the “wedge shape”, so that it is difficult for the pin47to be caught by the convex portions58. Therefore, a large resistance force is not generated when the pin47passes between the convex portions58. For this reason, since the resistance force at the time of the movement is smaller than that when the second cylinder36moves from the protruding position61to the received position62, a load applied to the user's fingers when moving the second cylinder36from the received position62to the protruding position61is reduced. On the other hand, since a predetermined frictional force acts when the pin47passes through the convex portion58, the positioning portion41prevents the second cylinder36from being moved from the received position62to the protruding position61when the user does not intend this movement.

Fourth Modified Example

FIG. 11shows a positioning portion41of an endoscope system11according to a fourth modified example. In the present modified example, a structure of the positioning portion41is different from those of the above embodiment and the above modified examples.

As shown inFIG. 11, the positioning portion41includes a pair of convex portions58protruding into the groove portion46of the first cylinder35. Each of the convex portions58is formed in, for example, a trapezoidal shape. One leg (first leg66) of the trapezoidal shape of the convex portion58is orthogonal to the center axis C (a moving direction of the pin47or the center axis D of the groove) of the first cylinder35, and the other leg (second leg67) of the trapezoidal shape of the convex portion58is oblique with respect to the center axis C (the moving direction of the pin47or the center axis D of the groove) of the first cylinder35.

The groove portion46has a shape (slotted shape) in which an opening portion is in communication with the outside. The first cylinder35may have a plurality of slits extending in the direction of the center axis C of the first cylinder35, in addition to the groove portion46. In addition to the groove portion46, one slit is provided or a plurality of slits are provided, so that rigidity of the first main body43of the first cylinder35is reduced, and the first cylinder35is easily elastically deformed in the vicinity of the positioning portion41.

An operation of the endoscope system11according to the fourth modified example will be described.

When the second cylinder36(seeFIG. 3) moves from the protruding position61at which it protrudes from the first cylinder35to the received position62at which it is received in the first cylinder35, the pin47abuts on the convex portions58(the first legs66) of the positioning portion41to pass between the convex portions58while elastically deforming a part of the first main body43of the first cylinder35as represented by a two-dot chain line inFIG. 11. In this case, since the moving direction of the pin47and a direction of the first leg66are perpendicular to each other, a force required for elastically deforming the first main body43of the first cylinder35is relatively large. Since a resistance force is generated by a reaction of the force for elastically deforming the first main body43as described above, the second cylinder36is prevented from being moved from the protruding position61to the received position62when the user does not intend this movement. In this case, it becomes difficult for the second cylinder36to move from the protruding position61to the received position62, but as the second cylinder36moves from the protruding position61to the received position62, the restoring force of the tension spring of the assisting portion38acts. For this reason, since the resistance force at the time of the movement is smaller than that when the second cylinder36moves from the received position62to the protruding position61, a load applied to the user's fingers when moving the second cylinder36from the protruding position61to the received position62is reduced.

On the other hand, when the second cylinder36moves from the received position62at which it is received in the first cylinder35to the protruding position61, the pin47abuts on the convex portions58(the second legs67) of the positioning portion41to pass between the convex portions58while elastically deforming a part of the first main body43of the first cylinder35. In this case, since the moving direction of the pin47and a direction of the second leg67are oblique with respect to each other, the force necessary for elastically deforming the first main body43of the first cylinder35is smaller than that when the second cylinder36moves from the protruding position61to the received position62. However, even in such a case, a slight force is required for elastically deforming the first main body43, so that the second cylinder36is prevented from being moved from the received position62to the protruding position61when the user does not intend this movement. In this case, the movement of the second cylinder36from the received position62to the protruding position61corresponds to an operation of moving the fingers in the direction in which the fingers approach the palm surface63to rotate the dial45. For this reason, the rotation of the dial45in this direction is an operation in which it is ergonomically easy to apply a force, so that an advance and retreat operation of the treatment instrument13is not hindered.

Fifth Modified Example

An endoscope system11according to a fifth modified example will be described with reference toFIGS. 12 and 13. In the present modified example, structures of an advance and retreat mechanism37and an assisting portion38are different from those of the above embodiment and the above modified examples.

The advance and retreat mechanism37includes a dial45and a cam mechanism56(transfer portion) converting rotation of the dial45into advance and retreat of the second cylinder36(treatment instrument13). The dial45is provided so as to be rotatable around the rotation shaft55provided on the first arm portion44of the first cylinder35. The cam mechanism56includes a cam groove57formed in a spiral shape on an outer circumferential surface of the dial45and a pin47formed in the second cylinder36so as to protrude from the second main body51. In the present modified example, the cam groove57is formed in a spiral shape in an opposite direction to that of the above embodiment. For this reason, when viewed from the opposite side to the base33, when the dial45is rotated clockwise, the pin47is moved toward the opposite side to the base33by an action of the cam groove57. When viewed from the opposite side to the base33, when the dial45is rotated counterclockwise, the pin47is moved toward the base33by an action of the cam groove57.

The assisting portion38is formed of a compression spring (compression coil spring) spanned between the first cylinder35and the holding member53of the second cylinder36. The assisting portion38may be spanned between the base33and the second cylinder36as in the above embodiment.

An effect of the present modified example will be described with reference toFIGS. 12 and 13.

When the user wants to advance the treatment instrument13by further protruding the treatment instrument13from the endoscope12, the user moves the fingers64in the direction in which the fingers64approach the palm surface63to rotate the dial45in the counterclockwise direction when viewed from the opposite side to the base33. As a result, the pin47and the second cylinder36are moved toward the treatment instrument insertion port31(received position62) by an action of the cam groove57. In this case, as shown inFIG. 12, a force acts so as to compress the compression spring of the assisting portion38, and a force acting as a reaction to the force thus becomes a resistance force when moving the second cylinder36. However, since an operation of moving the fingers64in the direction in which the fingers64approach the palm surface63is an operation in which it is ergonomically easy to apply a force, the rotation of the dial45in the counterclockwise direction (advance of the treatment instrument13) is hardly hindered.

On the other hand, when the user wants to retreat the treatment instrument13so as to return the treatment instrument13toward the endoscope12, the user moves the fingers in the direction in which the fingers becomes distant from the palm surface63to rotate the dial45in the clockwise direction when viewed from the opposite side to the base33. As a result, the pin47and the second cylinder36are moved toward the opposite side (protruding position61) to the treatment instrument insertion port31by an action of the cam groove57. In this case, as shown inFIG. 12, a restoring force of the compression spring of the assisting portion38acts to assist the movement of the second cylinder36, and a force for rotating the dial45in the clockwise direction is thus reduced. As a result, even in a case where the user moves the fingers in the direction in which it is ergonomically difficult to apply the force, the rotation of the dial45and the advance of the treatment instrument13are assisted by an action of the assisting portion38. In this example, the movement between the protruding position61and the received position62has been described by way of example, but the same effect is also achieved in the movement at an intermediate position between the protruding position61and the received position62.

Sixth Modified Example

An endoscope system11according to a sixth modified example will be described with reference toFIGS. 14 and 15. In the present modified example, a position at which an assisting portion38is installed is different from those of the above embodiment and the above modified examples.

The assisting portion38is formed of a tension spring (tension coil spring) spanned between the first cylinder35and the second cylinder36. The assisting portion38is disposed inside the first cylinder35.

An effect of the present modified example will be described with reference toFIGS. 14 and 15.

When the user wants to advance the treatment instrument13by further protruding the treatment instrument13from the endoscope12, the user moves the fingers64in the direction in which the fingers64become distant from the palm surface63to rotate the dial45in the clockwise direction when viewed from a distal end side opposite to the first arm portion44of the rotation shaft55. As a result, the pin47and the second cylinder36are moved toward the treatment instrument insertion port31(base33) by an action of the cam groove57. In this case, as shown inFIG. 14, the restoring force of the tension spring of the assisting portion38acts to urge the second cylinder36toward the base33, thereby assisting the movement of the second cylinder36. Therefore, a force for rotating the dial45in the clockwise direction is reduced. As a result, even in a case where the user moves the fingers in the direction in which it is ergonomically difficult to apply the force, the rotation of the dial45and the advance of the treatment instrument13are assisted by an action of the assisting portion38.

On the other hand, when the user wants to retreat the treatment instrument13so as to return the treatment instrument13toward the endoscope12, the user moves the fingers in the direction in which the fingers approach the palm surface63to rotate the dial45in the counterclockwise direction when viewed from a distal end side of the rotation shaft55. As a result, the pin47and the second cylinder36are moved toward the opposite side to the treatment instrument insertion port31by an action of the cam groove57. In this case, as shown inFIG. 15, the restoring force of the tension spring of the assisting portion38becomes a resistance of the movement of the second cylinder36. However, since an operation of moving the fingers in the direction in which the fingers approach the palm surface63is an operation in which it is ergonomically easy to apply a force, the rotation of the dial45in the counterclockwise direction (retreat of the treatment instrument13) is hardly hindered. In this example, the movement between the protruding position61and the received position62has been described by way of example, but the same effect is also achieved in the movement at an intermediate position between the protruding position61and the received position62.

Seventh Modified Example

An endoscope system11according to a seventh modified example will be described with reference toFIGS. 16 and 17. In the present modified example, a structure of a positioning portion41is different from those of the above embodiment and the above modified example.

As shown inFIG. 16, the positioning portion41is distributed and provided at a plurality of positions along the direction of the center axis C of the first cylinder35in the groove of the first cylinder35. That is, the positioning portion41has a plurality of sets of convex portions58distributed and disposed along the direction of the center axis C of the first cylinder35. The respective convex portions58are provided to face each other in the groove46.

Each of the convex portions58is formed in a “wedge shape” protruding so as to approach the center axis D of the groove as the distance to the end portion46B on the opposite side to the bottom portion46A of the groove portion46is decreased. As shown inFIG. 16, when the second cylinder36moves from the protruding position61to the received position62, the pin47has a structure in which it is caught by the convex portions58. Therefore, a large resistance force is generated when the pin47passes between the convex portions58. On the other hand, as shown inFIG. 17, when the second cylinder36moves from the received position62to the protruding position61, although a predetermined resistance force is applied to the pin47when the pin47passes between the convex portions58, the second cylinder36can be moved with a relatively small force.

In the present modified example, a plurality of intermediate positions are defined between the protruding position61at which the second cylinder36protrudes from the first cylinder35and the received position62at which the second cylinder36is received in the first cylinder35. In the present modified example, two intermediate positions are provided. A first intermediate position71is set to a position close to the protruding position61, and this position is defined by a second convex portion58from the end portion46B of the groove46and the pin47. A second intermediate position72is set to a position close to the received position62, and this position is defined by a second convex portion58from the bottom portion46A of the groove46and the pin47. It should be noted that two or more intermediate positions may be set.

An effect of the present modified example will be described with reference toFIGS. 16 and 17.

When the user wants to advance the treatment instrument13or wants to retreat the treatment instrument13, the user can advance or retreat the treatment instrument13by rotating the dial45in the clockwise direction or the counterclockwise direction when viewed from the opposite side of the base33, as in the above embodiment. In the present modified example, further, the user can not only fixedly hold the pin47and the second cylinder36at the protruding position61and the received position62by the positioning portion41, but also fixedly hold the pin47and the second cylinder36at the intermediate positions (the first intermediate position71and the second intermediate position72) between the protruding position61and the received position62by the positioning portion41.

According to the present modified example, the positioning portion41is provided between the first cylinder35and the second cylinder36, and defines a relative positional relationship between the first cylinder35and the second cylinder36in the direction of the center axis C in a plurality of steps. According to such a configuration, for example, the following treatment can be performed. For example, under view of the endoscope12, when, for example, the innermost part is treated in a hole of a medical examinee (subject), the treatment instrument13can be held at the most advanced position. In addition, when a front side is treated in the hole of the medical examinee, the treatment instrument13can be held at the most retreated position. Further, when an intermediate position between the innermost part and the front side is treated in the hole of the medical examinee, the treatment instrument13is held at the intermediate position between the innermost part and the front side. As described above, the endoscope system according to present modified example is particularly useful, for example, when the user wants to change a position of the treatment instrument13stepwise in the direction of the center axis C depending on a position at which the treatment is performed with the treatment instrument13.

Eighth Modified Example

An endoscope system according to an eighth modified example will be described with reference toFIG. 18. In the present modified example, a position at which a positioning portion is provided and a structure of the positioning portion are different from those in the above embodiment and the above modified examples.

In the present modified example, the positioning portion41is provided in the dial45rather than in the groove of the first cylinder35. More specifically, the positioning portion41is formed as a plurality of grooves that are in communication with a cam groove57formed in the dial45.FIG. 18is a view schematically showing an outer circumferential portion of the dial45formed in an approximately cylindrical shape in a state where the outer circumferential portion of the dial45is developed in a plane. The cam groove57has a first end portion73positioned adjacent to the base33and a second end portion74positioned on an opposite side of the base33.

The positioning portion41has a first holding portion75formed so as to be in communication with the first end portion73and having a groove shape, a second holding portion76formed so as to be in communication with the second end portion74and having a groove shape, and a third holding portion77formed at an intermediate position between the first end portion73and the second end portion74so as to be in communication with the cam groove57and having a groove shape. The positioning portion41(the first holding portion75, the second holding portion76, and the third holding portion77) is provided in a direction orthogonal to an extending direction E of the rotation shaft55.

An effect of the present modified example will be described with reference toFIG. 18.

When the user wants to advance the treatment instrument13or wants to retreat the treatment instrument13, the user can advance or retreat the treatment instrument13by rotating the dial45in the clockwise direction or the counterclockwise direction when viewed from the opposite side of the base33, as in the above embodiment. In the present modified example, further, the user can fixedly hold the second cylinder36at the received position by moving the pin47into the first holding portion75. In addition, the user can fixedly hold the second cylinder36at the protruding position61by moving the pin47into the second holding portion76. Further, the user can fixedly hold the second cylinder36at an intermediate position between the received position62and the protruding position61by moving the pin47into the third holding portion77.

Therefore, according to the present modified example, an effect that is substantially the same as that of the seventh modified example is achieved.

Ninth Modified Example

An endoscope system11according to a ninth modified example will be described with reference toFIGS. 19 and 20. In the present modified example, a structure in which a second cylinder36covers an outer side of a first cylinder35is different from those of the above embodiment and the above modified examples.

In the present modified example, the second cylinder36is formed to have an inner diameter larger than an outer diameter of the first cylinder35, unlike the above embodiment.

An effect of the present modified example will be described with reference toFIGS. 19 and 20.

When the user wants to advance the treatment instrument13by further protruding the treatment instrument13from the endoscope12, the user moves the fingers64in the direction in which the fingers64become distant from the palm surface63to rotate the dial45in the clockwise direction when viewed from the opposite side to the base33. As a result, the pin47and the second cylinder36are moved toward the treatment instrument insertion port31(base33) by an action of the cam groove57. In this case, the second cylinder36covers the outer side of the first cylinder35. In the present modified example, the second cylinder36is received inside the first cylinder35at the received position62. In this case, as shown inFIG. 19, the restoring force of the tension spring of the assisting portion38acts to urge the second cylinder36toward the base33, thereby assisting the movement of the second cylinder36. Therefore, a force for rotating the dial45in the clockwise direction is reduced. As a result, even in a case where the user moves the fingers in the direction in which it is ergonomically difficult to apply the force, the rotation of the dial45and the advance of the treatment instrument13are assisted by an action of the assisting portion38.

On the other hand, when the user wants to retreat the treatment instrument13so as to return the treatment instrument13toward the endoscope12, the user moves the fingers64in the direction in which the fingers64approach the palm surface63to rotate the dial45in the counterclockwise direction when viewed from the opposite side to the base33. As a result, the pin47and the second cylinder36are moved toward the opposite side (protruding position61) to the treatment instrument insertion port31by an action of the cam groove57. In the present modified example, the second cylinder36protrudes toward a distal end side of the first cylinder35at the protruding position61. In this case, as shown inFIG. 20, the restoring force of the tension spring of the assisting portion38becomes a resistance of the movement of the second cylinder36. However, since an operation of moving the fingers in the direction in which the fingers approach the palm surface63is an operation in which it is ergonomically easy to apply a force, the rotation of the dial45in the counterclockwise direction (retreat of the treatment instrument13) is hardly hindered. In this example, the movement between the protruding position61and the received position62has been described by way of example, but the same effect is also achieved in the movement at an intermediate position between the protruding position61and the received position62.

According to the present modified example, in the advance and retreat assisting tool14for a treatment instrument, the inner diameter of the second cylinder36is larger than the outer diameter of the first cylinder35, and the second cylinder36is advanced and retreated between a position in a state where the first cylinder35is inserted into the second cylinder36and a position in a state where the first cylinder35protrudes from the second cylinder36. According to such a configuration, it is possible to realize a configuration in which the second cylinder36moves with respect to the first cylinder35with a simple structure.

Tenth Modified Example

An endoscope system according to a tenth modified example will be described with reference toFIGS. 21 to 26. In the present modified example, a structure in which a second cylinder36is moved with respect to a first cylinder35and a configuration and a disposition of an assisting portion38are different from those of the above embodiment and the above modified examples.

A long portion78has a length from the treatment instrument insertion portion31to the distal end constituting portion22of the insertion portion17, and is arranged from the treatment instrument insertion port31to the side of the distal end constituting portion22of the insertion portion17. The long portion78has a longitudinal axis. The second cylinder36can be advanced and retreated between the protruding position61and the received position62with respect to the first cylinder35through the long portion78and a long portion fixing portion81fixing one end of the long portion78and the second cylinder36to each other. The long portion78is pulled from the operation portion18toward the distal end constituting portion22to be advanced along a longitudinal axis direction of the long portion78. As a result, the long portion78moves toward the received position62with respect to the first cylinder35through the long portion fixing portion81(seeFIG. 22). In addition, the long portion78is pushed back from the distal end constituting portion22to the operation portion18, so that the long portion78is retreated along the longitudinal axis direction of the long portion78. As a result, the long portion78moves to the protruding position61with respect to the first cylinder35through the long portion fixing portion81(seeFIG. 21). In order to advance and retreat the long portion78, the advance and retreat assisting tool14has a long operation portion α at one end of the long portion78. As shown inFIGS. 24 and 25, the long operation portion α functions as, for example, a knob held by an operator. Further, the advance and retreat assisting tool14has a long guide member β guiding the long portion78by allowing the long portion78to be inserted into the long guide member. The long guide member β is formed as an elongated cylindrical member into which the long portion78is inserted. The long guide member β is shorter than the long portion78. The long guide member β is arranged from the base33to the tube portion24of the insertion portion17. In addition, the long guide member β has flexibility. The long guide member β is fixed to the base33. The long guide member β has a finger insertion portion γ (seeFIG. 24) into which any one of fingers64′ of an operator's hand is inserted in a state (seeFIG. 25) where the operator grasps the long portion78including the long guide member β and grips the long operation portion α with any one (seeFIG. 26) of the fingers64′ of his/her hand. The finger insertion portion γ is a belt-shaped member having a ring shape. The long operation portion α may have a ring shape into which any one (seeFIG. 26) of the fingers64′ of the operator's hand can be inserted. In addition, a size relationship between the first cylinder35and the second cylinder36is the same as that of the ninth modified example.

As shown inFIG. 21, the assisting portion38is formed of a tension spring (tension coil spring) spanned between the base33and the second cylinder36. As a further modification of the present modified example, the assisting portion38may be formed of a compression spring (compression coil spring) interposed between the base33and the second cylinder36. In this case, one end of the assisting portion38is fixed to the base33, and the other end of the assisting portion38is fixed to the second cylinder36. Alternatively, as a further modification of the present modified example, the assisting portion38may be formed of a tension spring (tension coil spring) spanned between a wire fixing portion81and the base33, as shown inFIG. 23. Alternatively, inFIG. 23, the assisting portion38may be formed of a compression spring (compression coil spring) interposed between the wire fixing portion81and the base33. In this case, one end of the assisting portion38is fixed to the base33, and the other end of the assisting portion38is fixed to the wire fixing portion81. The assisting portion38is disposed outside the first cylinder35.

The movement from the protruding position61to the received position62is to move the fingers64′ in a direction in which the fingers64′ become distant from a palm surface63′, which is a direction in which it is ergonomically difficult to apply a force, but is a direction in which an urging force of the assisting portion38is generated, and thus, sliding of the long portion78is assisted. According to such a configuration, it is possible to realize the advance and retreat assisting tool14for a treatment instrument in which user's operability is improved. On the other hand, the movement from the received position62to the protruding position61is to move the fingers64′ in a direction in which the fingers64′ approach the palm surface63′, which is an operation in which it is ergonomically easy to apply a force, and thus, sliding of the long portion78is not hindered by the assisting portion38.

According to the present modified example, the same effect as that of the ninth modified example is achieved.

Eleventh Modified Example

An endoscope system11according to an eleventh modified example will be described with reference toFIG. 27. In the present modified example, a structure in which a cam groove57is formed on an inner circumferential surface of a dial45and a configuration and a disposition of an assisting portion38are different from those in the above embodiment and the above modified examples.

The advance and retreat mechanism37includes a dial45and a cam mechanism56(transfer portion) converting rotation of the dial45into advance and retreat of the second cylinder36(treatment instrument13). The dial45is provided so as to be rotatable around the first cylinder35using the first cylinder35as a rotation shaft. An axial center of the first cylinder35that becomes the rotation axis coincides with the center axis C of the treatment instrument13. The cam mechanism56includes a cam groove57formed in a spiral shape on an inner circumferential surface of the dial45and a pin47formed in the second cylinder36so as to protrude from the second main body51. For this reason, the dial45is rotated by the user's fingers64, so that the second cylinder36can protrude from the first cylinder35or the second cylinder36can be received in the first cylinder35, by an action of the cam mechanism56(the cam groove57and the pin47). Therefore, the advance and retreat mechanism37can advance and retreat the treatment instrument13by rotating the dial45with the user's fingers. That is, when viewed from the opposite side to the base33, when the dial45is rotated clockwise, the pin47is moved toward the opposite side to the base33by an action of the cam groove57. Likewise, when viewed from the opposite side to the base33, when the dial45is rotated counterclockwise, the pin47is moved toward the base33by an action of the cam groove57.

The assisting portion38is formed of a tension spring (tension coil spring) spanned between the base33and the second cylinder36. As a further modification of the present modified example, the assisting portion38may be formed of a compression spring (compression coil spring) interposed between the base33and the second cylinder36. In this case, one end of the assisting portion38is fixed to the base33, and the other end of the assisting portion38is fixed to the second cylinder36. The assisting portion38may also be spanned between the first cylinder35and the second cylinder36. The assisting portion38is disposed within the first cylinder35and inside the dial45.

According to the present modified example, the same effect as that of the first embodiment is achieved. Alternatively, as a further modification of the eleventh modified example, as shown inFIGS. 28 and 29, the assisting portion38(tension spring) may be provided outside the first cylinder35and the dial45. As a further modification inFIGS. 28 and 29, the assisting portion38may be formed of a compression spring (compression coil spring).FIG. 28corresponds to a state where the second cylinder36is at the protruding position61.FIG. 29corresponds to a state where the second cylinder36is at the received position62. According to such a further modified example, the same effect as that of the above embodiment is achieved.

Twelfth Modified Example

An endoscope system11according to a twelfth modified example will be described with reference toFIG. 30. In the present modified example, a structure in which a sealing member (O-ring)84is disposed between a second cylinder36and a third cylinder83is different from those of the above embodiment and the above modified examples.

An advance and retreat assisting tool14includes a base33attached to the operation portion18, an attaching portion34attaching the base33to an endoscope12such that a through-hole33A of the base33faces a treatment instrument insertion port31of the endoscope12, a first cylinder35attached to the base33, a second cylinder36sliding in an advance and retreat direction with respect to the first cylinder35along a center axis C of the first cylinder35, a blocking member82attached to the base33so as to be positioned inside the second cylinder36, an advance and retreat mechanism37advancing and retreating the second cylinder36along the center axis C with respect to the first cylinder35, an assisting portion38assisting rotation of the advance and retreat mechanism37when the advance and retreat mechanism37is rotated in one direction, and a positioning portion41positioning the second cylinder36at a predetermined position with respect to the base33. The first cylinder35, the second cylinder36, the blocking member82, the advance and retreat mechanism37, and the assisting portion38constitute a moving unit42for advancing and retreating the treatment instrument13.

The blocking member82includes a third cylinder83provided inside the first cylinder35and having a cylindrical shape and a sealing member84provided in the vicinity of a distal end portion of the third cylinder83opposite to the base33. The third cylinder83has an overlap portion83A overlapping the second cylinder36in a state where it is at a protruding position61and a groove85provided in the overlap portion83A.

The groove85is recessed and formed in an annular shape in an outer circumferential portion of the third cylinder83in the overlap portion83A. The sealing member84is disposed inside the groove85. The sealing member84is an O ring formed of a material having rubber-like elasticity such as silicon rubber. The sealing member84is interposed between the outer circumferential portion of the third cylinder83and an inner circumferential surface of the second cylinder36. The sealing member84can be closely adhered to the inner circumferential surface of the second cylinder36.

An effect of the present modified example will be described with reference toFIG. 30.

In the present modified example, similar to the above embodiment, the user rotates the dial45in the clockwise direction or the counterclockwise direction when viewed from the side opposite to the base33, thereby moving the second cylinder36between the received position62and the protruding position61with respect to the first cylinder35. In this case, the sealing member84is closely adhered to the inner circumferential surface of the second cylinder36regardless of a position of the second cylinder36. In addition, when the second cylinder36moves, the sealing member84slides with respect to the inner circumferential surface of the second cylinder36. Meanwhile, in the second cylinder36, due to a fixing structure (watertight structure) through a fixing portion54and a fastening portion59, a liquid is prevented from being leaked to the outside of the second cylinder36along the treatment instrument13. For this reason, even though the liquid such as a body fluid of a medical examinee (subject) bleeds along the treatment instrument13, the leak of the liquid is prevented by the blocking member82and the watertight structure through the fixing portion54and the fastening portion59, so that the liquid is not leaked to the outside of the second cylinder36.

According to the present modified example, the advance and retreat assisting tool14for a treatment instrument includes the blocking member82abutting on the inner circumferential surface of the second cylinder36to block movement of the liquid between the inside of the second cylinder36and the outside of the second cylinder36. According to such a configuration, since the liquid rising along the treatment instrument13can be confined to the outside of the second cylinder36by the blocking member82, members disposed in the vicinity of the second cylinder36can be maintained in a clean state without being into contact with the liquid.

Second Embodiment

An endoscope system11according to a second embodiment will be described with reference toFIGS. 31 to 35. In the endoscope system11according to the second embodiment, a structure of an advance and retreat assisting tool14is different from of that of the first embodiment, but the other parts are common to those of the first embodiment. In the following, parts different from those of the above embodiment will be mainly described, and illustration or description of parts common to those of the above embodiment will be omitted.

As shown inFIGS. 31 and 32, the advance and retreat assisting tool14includes a base33attached to an operation portion18, an attaching portion34attaching the base33to an endoscope12such that a through-hole33A of the base33faces a treatment instrument insertion port31of the endoscope12, a first cylinder35attached to the base33, a second cylinder36sliding in an advance and retreat direction with respect to the first cylinder35along a center axis C of the first cylinder35, an advance and retreat mechanism37advancing and retreating the second cylinder36along the center axis C with respect to the first cylinder35, an assisting portion38assisting rotation of the advance and retreat mechanism37when the advance and retreat mechanism37rotates in one direction, and a positioning portion41positioning the second cylinder36at a predetermined position with respect to the base33. The first cylinder35, the second cylinder36, the advance and retreat mechanism37, the assisting portion38, and the positioning portion41constitute a moving unit42for advancing and retreating a treatment instrument13. The moving unit42is attached to the base33through a first engaging portion91to be described below.

The first cylinder35has an insertion portion86which is inserted into the through-hole33A of the base33, the first engaging portion91which is formed on the insertion portion86, and a pair of receiving portions92which are formed in the insertion portion86and into which a distal end of a fixing member65is fitted. The insertion portion86has a cylindrical shape. The pair of receiving portions92are formed on an outer circumferential surface of the insertion portion86. The pair of receiving portions92are provided, respectively, on both sides having the first engaging portion91sandwiched therebetween. Each of the receiving portions92has a groove shape extending in a direction orthogonal to an insertion direction of the insertion portion86(a direction of the center axis C of the first cylinder35).

The first engaging portion91is formed as a projection protruding in a radial direction of the first cylinder35from a main body of the insertion portion86. The first engaging portion91is also referred to as a projection protruding toward the base33. In the present embodiment, the first engaging portion91is formed as a pair of projections, and this pair of projections function as one long positioning member93represented by a two-dot chain line inFIG. 31. The first engaging portion91may be provided as a plurality of projection pairs rather than a pair of projections on the insertion portion86. Alternatively, the first engaging portion91may be formed as a recess formed along the radial direction of the first cylinder35.

The base33has the through-hole33A through which the treatment instrument13passes. The base33can cover, for example, a forcep plug32from an upper side (seeFIG. 27and the like). The base33has a second engaging portion94capable of receiving the first engaging portion91formed in the first cylinder35(moving unit42). The base33has a through-hole through which the fixing member65(screw) passes.

The second engaging portion94can engage with the first engaging portion91(the positioning member93) such that a plurality of positions at which attachment angles of the moving unit42to the base33are different from each other can be taken stepwise. The second engaging portion94is a plurality of concave portions formed along a radial direction of the base33. In other words, the second engaging portion94has a plurality of sets of concave portion pairs along the radial direction of the base33. As shown inFIG. 32, the second engaging portion94can receive the first engaging portion91(the positioning member93) at different angles. In a case where the first engaging portion91is formed as the recess along the radial direction of the first cylinder35, the second engaging portion94is formed as a protruding portion (protruding portion engaging with the recess of the first engaging portion91) protruding toward the center axis (the moving unit42) of the through-hole33A.

An effect of the endoscope system11according to the present embodiment will be described with reference toFIGS. 31 and 35.

As in the first embodiment, it is possible to advance and retreat the second cylinder36with respect to the first cylinder35by rotating a dial45in a clockwise direction or a counterclockwise direction when viewed from an opposite side to the base33. In the present embodiment, further, it is possible to adjust an attachment angle of the moving unit42to the base33depending on a size of a user's hand by adjusting an attachment angle of the first engaging portion91to the second engaging portion94. That is, in a case where a user having a relatively small hand uses the endoscope system11, such as a case where the user is a female doctor, it is possible to dispose the moving unit42and the dial45at positions close to the operation portion18of the endoscope12, as shown inFIG. 33, by engaging the first engaging portion91with the second engaging portion94at an appropriate position.

In a case where a user having a relatively large hand uses the endoscope system11, such as a case the user is a large doctor, it is possible to make a distance between the moving unit42and the operation portion18of the endoscope12an intermediate distance (general length), as shown inFIG. 34, by engaging the first engaging portion91with the second engaging portion94at an appropriate position. In a case where an advance and retreat operation of the treatment instrument13is not performed by the advance and retreat assisting tool14for a treatment instrument, it is possible to dispose the moving unit42and the dial45at positions distant from the operation portion18of the endoscope12, as shown inFIG. 35, by engaging the first engaging portion91with the second engaging portion94at an appropriate position.

According to the present embodiment, the advance and retreat assisting tool14for a treatment instrument can be configured as follows. The advance and retreat assisting tool14for a treatment instrument includes the base33which is attached to the endoscope12, the moving unit42which is attached to the base33through the first engaging portion91and advances and retreats the treatment instrument passing through the inside of the endoscope12, and the second engaging portion94which is provided in the base33and engages with the first engaging portion91such that the plurality of positions at which the attachment angles of the moving unit42to the base33are different from each other can be taken stepwise.

According to such a configuration, it is possible to allow the moving unit42to approach the endoscope12and allow the moving unit42to become distant from the endoscope12. As a result, it is possible to provide the advance and retreat assisting tool14for a treatment instrument easily used by a user regardless of a size of a user's hand. In addition, since it is possible to change the attachment angle of the moving unit42stepwise, it is possible to realize the advance and retreat assisting tool14for a treatment instrument easily used by the user by disposing the moving unit42at an appropriate position depending on the size of the user's hand. Further, in the case where the advance and retreat operation of the treatment instrument13is not performed by the advance and retreat assisting tool14for a treatment instrument, it is possible to dispose the moving unit42at the position distant from the operation portion18so as not to disturb an operation of the endoscope12.

The first engaging portion91is any one of the projection protruding toward the base33and the recess formed along the radial direction of the moving unit42. The second engaging portion94is the concave portion with which the projection engages when the first engaging portion91is the projection. The second engaging portion94is the protruding portion engaging with the recess when the first engaging portion91is the recess.

According to such a configuration, it is possible to realize the advance and retreat assisting tool14for a treatment instrument in which the attachment angle of the moving unit42can be changed by a simple structure using the projection and the concave portion or the recess and the protruding portion. As a result, it possible to realize the advance and retreat assisting tool for a treatment instrument easily used by the user regardless the size of the user's hand without extremely increasing the manufacturing cost of the advance and retreat assisting tool14for a treatment instrument.

Several embodiments have been specifically described hereinabove with reference to the drawings, but the present invention is not limited to the abovementioned embodiments, and can be embodied by modifying components without departing from the gist of the present invention. In each of the above embodiments and modified examples, the assisting portion38is formed of the spring. However, the assisting portion38is not limited to the spring, and may be an elastic member, a damper, or the like having rubber-like elasticity. In addition, it is possible to realize one endoscope system11or advance and retreat assisting tool14for a treatment instrument by appropriately combining the components in the abovementioned different embodiments with each other.

The applicant also recognizes structures described below as an invention.

[1] An advance and retreat assisting tool for a treatment instrument including:

a base which is attached to an endoscope,

a moving unit which is attached to the base through a first engaging portion and advances and retreats the treatment instrument passing through an inside of the endoscope, and

a second engaging portion which is provided in the base and engages with the first engaging portion such that a plurality of positions at which attachment angles of the moving unit to the base are different from each other can be taken stepwise.

[2] The advance and retreat assisting tool for a treatment instrument according to [1], wherein the first engaging portion is any one of a projection protruding toward the base and a recess provided in the moving unit, and

the second engaging portion is a concave portion with which the projection engages when the first engaging portion is the projection, or the second engaging portion is a protruding portion engaging with the recess when the first engaging portion is the recess.

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