Multi-bendable medical device

A medical device for multiple bends, includes a distal-side traction member which is inserted through the distal-side bending portion and the proximal-side bending portion, which is configured to bend the distal-side bending portion in the bending orientation, and which includes a distal-side fixing portion fixed to the distal end of the distal-side bending portion in the axial direction, and a proximal-side traction member which is inserted through the proximal-side bending portion, which is configured to bend the proximal-side bending portion in the bending orientation, and which includes a proximal-side fixing portion fixed to the distal end of the proximal-side bending portion in the axial direction. The proximal-side fixing portion is disposed at substantially the same position as the distal-side fixing portion in a circumferential direction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-bendable medical device in which a plurality of bending portions for bending operation are disposed in an insertion portion for insertion into a body.

2. Description of the Related Art

In Jpn. Pat. Appln. KOKAI Publication No. 2002-177200, an endoscope with two bends is disclosed. The endoscope with the two bends has an elongated insertion portion for insertion into a body. The insertion portion includes distal-side and proximal-side bending portions to be bent in vertical and horizontal directions in the distal end of the insertion portion. In a bending tube of each bending portion, many cylindrical bending pieces are axially coaxially arranged, and are rotationally connected to each other. The bending pieces adjoining to a predetermined bending piece on the distal and proximal sides are rotatable in the vertical direction and the horizontal direction, and the bending tube can be bent as a whole in an optional direction of the vertical and horizontal directions. At upper, lower, left and right positions in an internal peripheral portion of the bending piece, wire receiving portions are disposed. Through the wire receiving portions at the upper, lower, left and right positions, traction wires for bending motions in vertical and horizontal directions are passed, respectively. The distal ends of the traction wires are fixed to the distal end of the bending portion. The traction wires are passed through the insertion portion and introduced into an operation portion connected to the proximal end of the insertion portion. The traction of the traction wires for the bending motions in the vertical and horizontal directions makes it possible to bend the bending portion in the vertical and horizontal directions.

BRIEF SUMMARY OF THE INVENTION

According to one aspect of the present invention, there is provided a medical device for multiple bends includes an insertion portion which is configured to be inserted into a body and which includes a central axis and is configured to extend in an axial direction of the central axis, wherein:

the insertion portion includes:

a distal-side bending portion configured to bend in a bending orientation which is substantially orthogonal to the central axis,

a proximal-side bending portion which is disposed closer to a proximal side than the distal-side bending portion in the axial direction and which is configured to bend in the bending orientation,

a distal-side traction member which is inserted through the distal-side bending portion and the proximal-side bending portion and which is disposed on the side of the bending orientation, the distal-side traction member including a distal-side fixing portion fixed to the distal end of the distal-side bending portion in the axial direction, the distal-side traction member being pulled toward the proximal end in the axial direction to allow the distal-side bending portion to bend in the bending orientation,

a proximal-side traction member which is inserted through the proximal-side bending portion and which is disposed on the side of the bending orientation, the proximal-side traction member including a proximal-side fixing portion fixed to the distal end of the proximal-side bending portion in the axial direction, the proximal-side traction member being pulled toward the proximal end in the axial direction to allow the proximal-side bending portion to bend in the bending orientation, and

a holding portion which is provided at the distal end of the proximal-side bending portion in the axial direction and which is disposed on the side of the bending orientation and which is configured to hold the distal-side traction member movably back and forth in the axial direction, and

the proximal-side fixing portion is disposed at substantially the same position as the distal-side fixing portion in a circumferential direction of the central axis,

the holding portion is disposed at a position different from the proximal-side fixing portion in the circumferential direction,

the distal-side bending portion includes two or more substantially cylindrical bending members which are substantially coaxially arranged in the axial direction and which are rotatably connected to each other,

the two or more bending members include at least one through bending member,

the through bending member includes a through portion, the through portion being disposed on the side of the bending orientation, extending in the axial direction, and supporting the distal-side traction member, the distal-side traction member being inserted through the through portion movably back and forth in the axial direction, and

the through portion extends fully between the position of the distal-side fixing portion and the position of the holding portion in the circumferential direction.

DETAILED DESCRIPTION OF THE INVENTION

A first embodiment of the present invention is described with reference toFIG. 1toFIG. 2F.

Referring toFIG. 1, an endoscope for bi-bends includes an elongated insertion portion21for insertion into a body. The insertion portion21includes a hard tip portion22with rigidity, a bending part23for bending motion and an elongated flexible tube24with flexibility, and the hard tip portion22, the bending part23and the flexible tube24are continuously provided from a distal side to a proximal side of the insertion portion21. The bending part23includes distal-side bending portion25and proximal-side bending portion26. The distal-side and proximal-side bending portions25and26can be bent in a vertical direction that is orthogonal to the central axis of the insertion portion21, and in a horizontal direction that is orthogonal to the central axis and the vertical direction. The above vertical direction is composed of an upward orientation U and a downward orientation D mutually reversed, and the above horizontal direction is composed of a leftward orientation L and a rightward orientation R mutually reversed. The proximal end of the insertion portion21is connected with an operation portion27which is held and operated by an operator. The operation portion27includes a distal-side vertical bending operation knob28vwhich bends the distal-side bending portion25in the vertical direction, and a distal-side horizontal bending operation knob28hwhich bends the distal-side bending portion25in the horizontal direction. Furthermore, the operating portion27includes a proximal-side vertical bending operation knob29vwhich bends the proximal-side bending portion26in the vertical direction, and a horizontal bending operation knob29hwhich bends the proximal-side bending portion26in the horizontal direction.

The bending part23according to the present invention is described in detail with reference toFIG. 2AtoFIG. 2F.

Referring toFIG. 2A, bending tubes of the bending portions25and26include many substantially annular bending pieces as bending members which are axially coaxially arranged, and which are rotationally connected to each other. In the present embodiment, through pieces31as through bending members are used as many bending pieces. The through pieces31are integrally formed by, for example, cutting or injection molding. The through piece31includes an annular main body and a pair of rotation portions32which are formed in a circular surface at one end of the annular main body. The pair of rotation portions32project in the axial direction, assume a smooth arc-like outer shape when diametrically viewed, and are disposed symmetrically to each other with respect to a central axis. A circular surface at the other end of the main body serves as a rotation support surface33. The pair of rotation portions32of the other of the adjoining through pieces31are in contact with the rotation support surface33of one through piece31. The other through piece31can rotate, with respect to one through piece31, on the tops of the pair of rotation portions32around a rotation axis that passes the tops of the pair of rotation portions32and that is orthogonal to the central axis. Many pairs of rotation portions32of many through pieces31arranged in the axial direction are alternately disposed exactly at the top, bottom, left, and right. Many rotation axes are alternately disposed in the vertical and horizontal directions. The bending tubes can be bent as a whole in an optional direction of the vertical and horizontal directions.

Distal-side traction wires36u,36d,36land36ras distal-side traction members are inserted through the distal-side bending portion25and the proximal-side bending portion26. Proximal-side traction wires37u,37d,37land37ras proximal-side traction members are inserted through the proximal-side bending portion26.

Referring toFIG. 2AandFIG. 2B, a cylindrical distal fixing member34is coaxially connected to the most distal through piece31of the distal-side bending portion25. The distal ends of the distal-side traction wires36uto36rare fixed to the internal peripheral surface of the distal fixing member34, and distal-side wire fixing portions38u,38d,38land38rare formed by the distal ends of the distal-side traction wires36u,36d,36land36r. The distal-side wire fixing portions38uto38rof the distal-side traction wires36uto36rfor vertical and horizontal bending motions are disposed exactly at the top, bottom, left, and right, respectively.

Referring toFIG. 2AandFIG. 2D, the most proximal through piece31of the distal-side bending portion25is coaxially connected to the most distal through piece31of the proximal-side bending portion26by a cylindrical distal-side connecting member41. The distal ends of the proximal-side traction wires37uto37rare fixed to the internal peripheral surface of the distal-side connecting member41, and proximal-side wire fixing portions39u,39d,39land39rare formed by the distal ends of the proximal-side traction wires37u,37d,37land37r. The proximal-side wire fixing portions39uto39rare disposed at the same positions in the circumferential direction as the distal-side wire fixing portions38uto38r, respectively. That is, the proximal-side wire fixing portions39uto39rfor vertical and horizontal bending motions are disposed exactly at the top, bottom, left, and right in the circumferential direction, respectively.

In the proximal-side bending portion26, the distal-side traction wires36u,36d,36land36rare inserted axially movably back and forth through distal-side coil sheaths43u,43d,43land43r. The distal ends of the distal-side coil sheaths43u,43d,43land43rare fixed to the internal peripheral surface of the distal-side connecting member41, and form distal-side sheath fixing portions46u,46d,46land46ras holding portions. The distal-side sheath fixing portions46uto46rare disposed at circumferential positions slightly different from the proximal-side wire fixing portions39uto39rin one orientation in the circumferential direction, respectively. In other words, the distal-side sheath fixing portions46uto46rare disposed at circumferential positions slightly different from the distal-side wire fixing portions38uto38rin one orientation in the circumferential direction, respectively. That is, the distal-side sheath fixing portions46uto46rfor vertical and horizontal bending motions are circumferentially disposed on the left side of the top in the circumferential direction, on the right side of the bottom in the circumferential direction, on the lower side of the left in the circumferential direction, and on the upper side of the right in the circumferential direction, respectively.

Referring toFIG. 2AandFIG. 2F, a cylindrical proximal connecting member42is coaxially connected to the most proximal through piece31of the proximal-side bending portion26. The proximal-side traction wires37u,37d,37land37rare inserted axially movably back and forth through proximal-side coil sheaths44u,44d,44land44rin the flexible tube24. The distal ends of the proximal-side coil sheaths44u,44d,44land44rare fixed to the internal peripheral surface of the proximal connecting member42, and form proximal-side sheath fixing portions47u,47d,47land47r. The proximal-side sheath fixing portions47uto47rare disposed at the same positions in the circumferential direction as the proximal-side wire fixing portions39uto39r, respectively. That is, the proximal-side sheath fixing portions47uto47rfor vertical and horizontal bending motions are disposed exactly at the top, bottom, left, and right, respectively.

Referring toFIG. 2AandFIG. 2C, through-holes51u,51d,51land51rare axially formed as through portions through the through piece31of the distal-side bending portion25. The through-holes51uto51rare in the shape of long holes having a width slightly greater than the outside diameters of the distal-side traction wires36uto36r, respectively. The through-holes51uto51rrespectively extend, in the circumferential direction, fully between the positions of the distal-side wire fixing portions38uto38rand the positions of the distal-side sheath fixing portions46uto46rthat are disposed at positions slightly different from the distal-side wire fixing portions38uto38rin one orientation in the circumferential direction. That is, the through-holes51uto51rfor vertical and horizontal bending motions circumferentially extend from the top to the left in the circumferential direction, from the bottom to the right in the circumferential direction, from the left to the lower side in the circumferential direction, and from the right to the upper side in the circumferential direction, respectively.

The distal-side traction wires36uto36rare inserted through the through-holes51uto51rfrom the distal-side wire fixing portions38uto38rto the distal-side sheath fixing portions46uto46r, and extend toward the proximal end in the axial direction in such a manner as to be displaced in one orientation in the circumferential direction. That is, the distal-side traction wires36uto36rfor vertical and horizontal bending motions extend toward the proximal end in the axial direction in such a manner as to be displaced leftward from the top in the circumferential direction, rightward from the bottom in the circumferential direction, downward from the left in the circumferential direction, and upward from the right in the circumferential direction, respectively. The distal-side traction wires36uto36rare supported by the internal peripheral surfaces of the through-holes51uto51raxially movably back and forth and circumferentially movably in the through-holes51uto51r.

Referring toFIG. 2AandFIG. 2E, through-holes51u,51d,51land51rsimilar to the through-holes51uto51rof the distal-side bending portion25are also formed in the through piece31of the proximal-side bending portion26. The proximal-side traction wires37uto37rare respectively inserted through the through-holes51uto51rfrom the proximal-side wire fixing portions39uto39rto the proximal-side sheath fixing portions47uto47rthat are disposed at the same positions in the circumferential direction as the proximal-side wire fixing portions39uto39r, and extend toward the proximal end in the axial direction without being displaced in the circumferential direction. That is, the proximal-side traction wires37uto37rfor vertical and horizontal bending motions extend toward the proximal end in the axial direction without being displaced from the top, bottom, left, and right in the circumferential direction, respectively. The proximal-side traction wires37uto37rare axially movable back and forth in the through-holes51uto51r, and are supported by the internal peripheral surfaces of the through-holes51uto51r.

When the proximal-side vertical and horizontal bending operations knobs29vand29hare operated, the proximal-side traction wires37uto37rfor vertical and horizontal bending motions are pulled, and the proximal-side bending portion26is bent in the vertical and horizontal directions. Likewise, when the distal-side vertical and horizontal bending operations knobs28vand28hare operated, the distal-side traction wires36uto36rfor vertical and horizontal bending motions are pulled, and the distal-side bending portion25is bent in the vertical and horizontal directions.

The endoscope for the two bends according to the present embodiment has the following advantages.

In the endoscope for the two bends according to the present embodiment, the proximal-side wire fixing portions39uto39rare disposed at the same positions in the circumferential direction as the distal-side wire fixing portions38uto38r, respectively. Therefore, the bending orientation of the proximal-side bending portion26when the proximal-side traction wires37uto37rare pulled exactly corresponds to the bending orientation of the distal-side bending portion25when the distal-side traction wires36uto36rfor vertical and horizontal bending motions in the same orientation are pulled. Consequently, the distal end of the insertion portion21can be precisely operated.

Furthermore, in the through piece31of the distal-side bending portion25, the through-holes51uto51rrespectively extend, in the circumferential direction, fully between the positions of the distal-side wire fixing portions38uto38rand the positions of the distal-side sheath fixing portions46uto46rthat are disposed at positions different from the distal-side wire fixing portions38uto38rin one orientation in the circumferential direction. Thus, excessive interference between the distal-side traction wires36uto36rand the internal peripheral surfaces of the through-holes51uto51ris prevented when the distal-side traction wires36uto36rare pulled. Moreover, a common member can be used as many through pieces31that constitute the distal-side bending portion25. This enables the reduction of the manufacturing costs of the endoscope for the two bends.

Although the through pieces integrally formed by, for example, cutting or injection molding including the through-holes are used in the present embodiment, through pieces having wire receptions formed by, for example, soldering a wire reception material to a main body member may be used instead.

A second embodiment of the present invention is described with reference toFIG. 3AtoFIG. 8B.

In the distal-side bending portion according to the first embodiment, when the pulling of the traction wires is canceled to return the bending portion from a bent condition to a non-bent neutral condition, a bending skip that causes the bending portion to be bent in the reverse orientation beyond the non-bent neutral condition may occur.

According to the present embodiment, the distal end of an insertion portion can be more precisely operated by preventing the bending skip.

Referring toFIG. 6AandFIG. 6B, in a bending portion25, regulation pieces53as regulation bending members are used as many bending pieces in addition to through pieces31similar to those in the first embodiment. In the present embodiment, among 14 bending pieces, the second, fifth, eighth, and eleventh bending pieces from the proximal side serve as the regulation pieces53, and the other bending pieces serve as the through pieces31.

Regulation holes56u,56d,56land56rare axially formed as regulation through portions through the regulation piece53. The regulation holes56uto56rare in the shape of circular holes having an inside diameter slightly greater than the outside diameters of distal-side traction wires36uto36r, respectively. The regulation holes56uto56rare disposed, in the circumferential direction, between the positions of distal-side wire fixing portions38uto38rand the positions of distal-side sheath fixing portions46uto46rthat are disposed at positions slightly different from the distal-side wire fixing portions38uto38rin one orientation in the circumferential direction. That is, the regulation holes56uto56rfor vertical and horizontal bending motions are circumferentially disposed on the left side of the top in the circumferential direction, on the right side of the bottom in the circumferential direction, on the lower side of the left in the circumferential direction, and on the upper side of the right in the circumferential direction, respectively. The distal-side traction wires36uto36rare inserted through through-holes51uto51rof the through pieces31and through the regulation holes56uto56rof the regulation pieces53, respectively. In the regulation holes56uto56r, the traction wires36uto36rare supported by the internal peripheral surfaces of the regulation holes56uto56raxially movably back and forth and circumferentially immovably.

In other words, wire fixing portions38uand38dfor vertical bending motion are respectively disposed on a vertical rotation axis Ov of the bending pieces31and53that can rotate in the horizontal direction, and sheath fixing portions46uand46dfor vertical bending motion are respectively disposed on the left and right sides of the vertical rotation axis Ov. Through-holes51uand51dfor vertical bending motion respectively extend to the left and right from the vertical rotation axis Ov with respect to the bending piece31. On the other hand, in the regulation piece53, the regulation holes56u,56dfor vertical bending motion are respectively disposed on the left and right sides of the vertical rotation axis Ov.

Likewise, the wire fixing portions38land38rfor horizontal bending motion are respectively disposed on a horizontal rotation axis Oh of the bending pieces31and53that can rotate in the vertical direction, and sheath fixing portions46land46dfor horizontal bending motion are respectively disposed on the lower side and upper side of the horizontal rotation axis Oh. Through-holes51land51rfor horizontal bending motion respectively extend to the lower side and upper side from the horizontal rotation axis Oh with respect to the bending piece31. On the other hand, in the regulation piece53, the regulation holes56l,56rfor horizontal bending motion are respectively disposed on the lower side and upper side of the horizontal rotation axis Oh.

The bending skip in the bending portion according to the first embodiment is described with reference toFIG. 3AtoFIG. 5B.

Described below is a leftward bending skip that is caused by the traction wire36ufor upward bending motion when the distal-side bending portion25is returned to a non-bent neutral condition from a rightward bent condition.

As shown inFIG. 3AandFIG. 3B, when the bending portion25is in the non-bent neutral condition, the traction wire36ufor upward bending motion is disposed on the left side of the vertical rotation axis Ov of the bending pieces31capable of rotating in the horizontal direction in the through-hole51ufor vertical bending motion.

As shown inFIG. 4AandFIG. 4B, when the traction wire36rfor rightward bending motion is pulled to bend the bending portion25rightward from the non-bent neutral condition, the traction wire36ufor upward bending motion is drawn toward the distal end in the axial direction by the rightward bending motion of the bending portion25. Sufficiently high axial tension is applied in advance to the traction wires36uto36rto enable smooth bending motion. When drawn toward the distal end in the axial direction, the traction wire36ufor upward bending motion is moved rightward in the through-hole51ufor upward bending motion, and comes into contact with the right end wall of the through-hole51ufor upward bending motion. Here, the through-hole51ufor upward bending motion extends up to the vertical rotation axis Ov in the horizontal direction, and the traction wire36ufor upward bending motion is disposed on the vertical rotation axis Ov. In addition, when the traction wire36ufor upward bending motion is drawn toward the distal end in the axial direction, the axial tension applied to the traction wire36ufor upward bending motion is further increased, and the traction wire36ufor upward bending motion is stretched and deformed in the axial direction by elastic deformation.

Furthermore, the pulling of the traction wire36rfor rightward bending motion is canceled to return the bending portion25from the rightward bent condition to the non-bent neutral condition. At the same time, the axial tension applied to the traction wire36ufor upward bending motion is rapidly decreased, the traction wire36ufor upward bending motion is rapidly returned and deformed in the axial direction by elastic deformation and is thus rapidly moved leftward from the vertical rotation axis Ov in the through-hole51ufor upward bending motion. Further, the direction of moment acting on the bending portion25is rapidly changed from the direction to bend the bending portion25rightward to the direction to bend the bending portion25leftward.

Consequently, as shown inFIG. 5AandFIG. 5B, the bending skip that causes the bending portion25to be bent leftward beyond the non-bent neutral condition may occur.

When the bending portion25is returned to the non-bent neutral condition from the leftward bent condition, a rightward bending skip may occur due to the traction wire36dfor downward bending motion. Likewise, when the bending portion25is returned to the non-bent neutral condition from the vertically bent condition, a vertical bending skip may occur due to the traction wires36land36rfor horizontal bending action. When the bending portion25is returned to the non-bent neutral condition from the upward bent condition, a downward bending skip may occur due to the traction wire36lfor leftward bending motion. When the bending portion25is returned to the non-bent neutral condition from the downward bent condition, a upward bending skip may occur due to the traction wire36rfor rightward bending motion.

A bending skip preventing function in the bending portion25according to the present embodiment is described with reference toFIG. 6AtoFIG. 8B.

Described below is the function for preventing a leftward bending skip that may be caused by the traction wire36ufor upward bending action when the distal-side bending portion25is returned to a non-bent neutral condition from a rightward bent condition.

Referring toFIG. 6AandFIG. 6B, when the bending portion25is in the non-bent neutral condition, the traction wire36ufor upward bending motion is disposed on the left side of the vertical rotation axis Ov of the bending pieces31and53that can rotate in the horizontal direction.

Referring toFIG. 7AandFIG. 7B, when the traction wire36rfor rightward bending motion is pulled to bend the bending portion25rightward from the non-bent neutral condition, the traction wire36ufor upward bending motion is drawn toward the distal end in the axial direction by the rightward bending action of the bending portion25. Sufficiently high axial tension is applied in advance to the traction wire36ufor upward bending motion. The through-hole51ufor upward bending action extends up to the vertical rotation axis Ov in the horizontal direction. However, the regulation hole56uis disposed on the left side of the vertical rotation axis Ov in the horizontal direction. Thus, the rightward movement of the traction wire36ufor upward bending motion is regulated by the regulation hole56u, and in the through-hole51u, the traction wire36ufor upward bending action is only slightly moved rightward, and is not moved to the vertical rotation axis Ov and is held on the left side of the vertical rotation axis Ov. The axial tension applied to the traction wire36ufor upward bending motion is further increased by the rightward bending of the bending portion25, and the traction wire36ufor upward bending motion is stretched and deformed in the axial direction by elastic deformation.

Furthermore, the pulling of the traction wire36rfor rightward bending motion is canceled to return the bending portion25from the rightward bent condition to the non-bent neutral condition. At the same time, the axial tension applied to the traction wire36ufor upward bending motion is rapidly decreased, and the traction wire36uis rapidly returned and deformed in the axial direction by elastic deformation. However, the traction wire36uis held on the left side of the vertical rotation axis Ov, so that the traction wire36ufor upward bending motion is not rapidly moved leftward. Further, the direction of moment acting on the bending portion25is not rapidly changed from the direction to bend the bending portion25rightward to the direction to bend the bending portion25leftward.

Consequently, the bending skip shown inFIG. 8AandFIG. 8Bthat causes the bending portion25to be bent leftward beyond the non-bent neutral condition does not occur.

When the curving portion25is curved leftward, the traction wire36dfor downward curving motion is held on the right side of the up-and-down direction rotation axis Ov by the regulation hole56dfor downward bending motion. Thus, when the bending portion25is returned to the non-bent neutral condition from the leftward bent condition, the rightward bending skip caused by the traction wire36dfor downward bending operation is prevented. When the bending portion25is returned to the non-bent neutral condition from the upward curved condition, downward bending skip caused by the traction wire36lfor the leftward bending motion is prevented. When the bending portion25is returned to the non-bent neutral condition from the downward curved condition, upward bending skip caused by the traction wire36rfor rightward bending motion is prevented.

The endoscope for the two bends according to the present embodiment has the following advantages.

In the endoscope for the two bends according to the present embodiment, when the bending portion25is bent in the right and left orientations, the traction wires36uand36dfor vertical bending motion are respectively held, by the regulation holes56uand56dof the regulation piece53for vertical bending motion, on the left and right sides of the vertical rotation axis Ov of the bending pieces31and53that can rotate in the horizontal direction in the through-holes51uto51rfor vertical bending motion. Thus, when the bending portion25is returned to the non-bent neutral condition from the right and left bent conditions, leftward and rightward bending skips respectively caused by the traction wires36uand36dfor upward and downward bending actions are prevented. Likewise, when the curving portion25is returned to the non-curved neutral condition from the upward and downward curved conditions, downward and upward curving skips respectively caused by the traction wires36land36rfor leftward and rightward curving operations are prevented.

A third embodiment of the present invention is described with reference toFIG. 9AtoFIG. 9B.

A bending portion25according to the present embodiment uses guide pieces61as bending pieces. Guide holes62u,62d,62land62rare axially formed through the guide piece61. The guide holes62uto62rare in the shape of circular holes having an outside diameter slightly greater than the outside diameters of the traction wires36uto36r, respectively. Here, wire fixing portions38uto38rare connected to sheath fixing portions46uto46rthat are disposed at positions slightly different from the wire fixing portions38uto38rin one orientation in the circumferential direction, and lines that axially extend in such a manner as to be displaced in the circumferential direction serve as reference lines, respectively. In each guide piece61, the guide holes62uto62rextend along the reference lines, respectively. Thus, excessive interference between the traction wires36uto36rand the internal peripheral surfaces of the guide holes62uto62ris prevented when the traction wires36uto36rare pulled.

As in the second embodiment, the guide holes62uto62rfor vertical and horizontal bending motions are disposed on the left and right sides of a vertical rotation axis Ov and on the lower side and upper side of a horizontal rotation axis Oh. Thus, when the bending portion25is returned to the non-curved neutral condition from the rightward, leftward, upward and down ward bending conditions, leftward rightward, downward and upward bending skips respectively caused by the traction wires36uto36rfor upward, downward, leftward and rightward bending actions are prevented.

The present invention is applicable to various multi-bendable medical devices in which a plurality of bending portions for bending action are disposed in an insertion portion for insertion into a body. For example, the present invention is not exclusively applicable to a two-bendable medical apparatus, and is also applicable to a multi-bendable medical device having three or more stages in which three or more bending portions are disposed in an insertion portion. Moreover, the present invention is not only applicable to the multi-bends endoscope, but also applicable to a multi-bends treatment instrument configured to treat a living tissue in a body or to a multi-bends over tube configured to assist the insertion of, for example, an endoscope into a body. In particular, the multi-bends treatment instrument has a treatment portion configured to treat a living tissue provided at the distal end of the insertion portion, and therefore requires precise motion of the treatment portion. Thus, the invention of the present application has a considerable advantage in enabling the precise motion of the distal end of the insertion portion. Further, the present invention is not exclusively applied to a manual multi-bends medical apparatus in which bending portions are manually driven, and is also applicable to an electric multi-bends medical apparatus in which bending portions are electrically driven.

In an aspect of the present invention, a medical device for multiple bends, includes an insertion portion which is configured to be inserted into a body and which includes a central axis and is configured to extend in an axial direction of the central axis, wherein: the insertion portion includes:

a distal-side bending portion configured to bend in a bending direction which is substantially orthogonal to the central axis,

a proximal-side bending portion which is disposed closer to a proximal side than the distal-side bending portion in the axial direction and which is configured to bend in the bending direction,

a distal-side traction member which is inserted through the distal-side bending portion and the proximal-side bending portion and which is disposed on the side of the bending direction, the distal-side traction member including a distal-side fixing portion fixed to the distal end of the distal-side bending portion in the axial direction, the distal-side traction member being pulled toward the proximal end in the axial direction to allow the distal-side bending portion to bend in the bending direction,

a proximal-side traction member which is inserted through the proximal-side bending portion and which is disposed on the side of the bending direction, the proximal-side traction member including a proximal-side fixing portion fixed to the distal end of the proximal-side bending portion in the axial direction, the proximal-side traction member being pulled toward the proximal end in the axial direction to allow the proximal-side bending portion to bend in the bending direction, and

a holding portion which is provided at the distal end of the proximal-side bending portion in the axial direction and which is disposed on the side of the bending direction and which is configured to hold the distal-side traction member movably back and forth in the axial direction,

the proximal-side fixing portion is disposed at substantially the same position as the distal-side fixing portion in a circumferential direction of the central axis,

the holding portion is disposed at a position different from the proximal-side fixing portion in the circumferential direction,

the distal-side bending portion includes two or more substantially cylindrical bending members which are substantially coaxially arranged in the axial direction and which are rotatably connected to each other,

the two or more bending members include at least one through bending member,

the through bending member includes a through portion, the through portion being disposed on the side of the bending direction, extending in the axial direction, and supporting the distal-side traction member, the distal-side traction member being inserted through the through portion movably back and forth in the axial direction, and

the through portion extends fully between the position of the distal-side fixing portion and the position of the holding portion in the circumferential direction.

In the medical apparatus for the multiple bend according to this aspect, the proximal-side fixing portion of the proximal-side traction member at the distal end of the proximal-side bending portion in the axial direction is disposed at substantially the same position in the circumferential direction as the distal-side fixing portion of the distal-side traction member at the distal end of the distal-side bending portion in the axial direction. Therefore, the bending orientation of the proximal-side bending portion can exactly correspond to the bending orientation of the distal-side bending portion, so that the distal end of the insertion portion can be precisely operated. Here, in the through bending member, the through portion extends fully between the position of the distal-side fixing portion and the position of the holding portion in the circumferential direction. Thus, excessive interference between the distal-side traction member and the through portion is prevented when the distal-side traction member is pulled.

In the aspect of the present invention, in the medical device, the two or more bending members include at least two through bending members.

In the medical device for the multiple bends according to this aspect, a common member can be used as the at least two through bending members that constitute the distal-side bending portion. This enables the reduction of the manufacturing costs of the medical device for the multiple bends.

In an aspect of the present invention, a medical device for multiple bends, includes an insertion portion which is configured to be inserted into a body and which includes a central axis and is configured to extend in an axial direction of the central axis, wherein the inserting portion includes:

a distal-side bending portion configured to bend in a first bending direction and a second bending direction, the first bending direction including a first bending orientation and a third bending orientation which are substantially orthogonal to the central axis and which are opposite to each other, the second bending direction including a second bending orientation and a fourth bending orientation which are substantially orthogonal to the central axis and the first bending direction and which are opposite to each other,

a proximal-side bending portion which is disposed closer to a proximal side than the distal-side bending portion in the axial direction and which is configured to bend in the first bending orientation,

a first distal-side traction member which is inserted through the distal-side bending portion and the proximal-side bending portion and which is disposed on the side of the first bending orientation, the first distal-side traction member including a first distal-side fixing portion fixed to the distal end of the distal-side bending portion in the axial direction, the first distal-side traction member being pulled toward the proximal end in the axial direction to allow the distal-side bending portion to bend in the first bending orientation,

a second distal-side traction member which is inserted through the distal-side bending portion and the proximal-side bending portion and which is disposed on the side of the second bending orientation, the second distal-side traction member including a second distal-side fixing portion fixed to the distal end of the distal-side bending portion in the axial direction, the second distal-side traction member being pulled toward the proximal end in the axial direction to allow the distal-side bending portion to bend in the second bending orientation,

a proximal-side traction member which is inserted through the proximal-side bending portion and which is disposed on the side of the bending orientation, the proximal-side traction member including a proximal-side fixing portion fixed to the distal end of the proximal-side bending portion in the axial direction, the proximal-side traction member being pulled toward the proximal end in the axial direction to allow the proximal-side bending portion to bend in the first bending orientation, and

a holding portion which is provided at the distal end of the proximal-side bending portion in the axial direction and which is disposed on the side of the bending orientation and which holds the distal-side traction member movably back and forth in the axial direction,

the proximal-side fixing portion is disposed at substantially the same position as the first distal-side fixing portion in a circumferential direction of the central axis,

the holding portion is disposed on the side of the fourth bending orientation with respect to the proximal-side fixing portion in the circumferential direction,

the distal-side bending portion includes three or more substantially cylindrical bending members which are substantially coaxially arranged in the axial direction and which are rotatably connected to each other, the three or more bending members including at least two bending members which are connected to each other rotatably in the first bending direction around a first rotation axis extending in the second bending direction, and at least two bending members which are connected to each other rotatably in the second bending direction around a second rotation axis extending in the first bending direction,

the three or more bending members include at least one through bending member,

the through bending member includes a through portion which is disposed on the side of the first bending orientation and which is extending in the axial direction, the first distal-side traction member being inserted through the through portion movably back and forth in the axial direction, and the through bending member supporting the first distal-side traction member,

the through portion extends fully between the position of the first distal-side fixing portion and the position of the holding portion in the circumferential direction,

the three or more bending members include at least one regulation bending member,

the regulation bending member includes a regulation through portion which is disposed on the side of the first bending orientation and which is extending in the axial direction, the first distal-side traction member being inserted through the regulation through portion movably back and forth in the axial direction, and the regulation through portion supporting the first distal-side traction member, and

the regulation through portion is disposed closer to the side of the fourth bending orientation than the second rotation axis in the second bending direction, and when the second distal-side traction member is pulled toward the proximal end in the axial direction to bend the distal-side bending portion in the second bending orientation, the regulation through portion regulates the movement of the first distal-side traction member to or beyond the second rotation axis in the through portion in the second bending orientation.

In the medical device for the multiple bends according to this aspect, when the regular bending member is not used, in order to pull the second distal-side traction member toward the proximal end in the axial direction to bend the distal-side bending portion in the second bending orientation, tension directed to the distal end in the axial direction is applied to the first distal-side traction member, the first distal-side traction member is moved to or beyond the second rotation axis in the through portion of the through bending member in the second bending orientation, and the first distal-side traction member is stretched and deformed in the axial direction. In order to cancel the pulling of the second distal-side traction member to return the distal-side bending portion from a condition bent in the second bending orientation to a non-bent neutral condition, the first distal-side traction member is rapidly moved in the fourth bending orientation in the through portion by the returning deformation of the first distal-side traction member resulting from the cancellation of the tension applied to the first distal-side traction member, and the direction of rotation moment acting on the distal-side bending portion is rapidly changed from the direction to bend the distal-side bending portion in the second bending orientation to the direction to bend the distal-side bending portion in the fourth bending orientation. This may lead to a bending skip that causes the distal-side bending portion to be rapidly bent in the fourth bending orientation beyond the non-bent neutral condition.

In the medical device for the multiple bends according to this aspect, when the second distal-side traction member is pulled toward the proximal end in the axial direction to bend the distal-side bending portion in the second bending orientation, the regulation through portion of the regulation bending member regulates the movement of the first distal-side traction member to or beyond the second rotation axis in the through portion of the through bending member in the second bending orientation. Therefore, in order to cancel the pulling of the second distal-side traction member to return the distal-side bending portion from the condition bent in the second bending orientation to the non-bent neutral condition, the first distal-side traction member is not rapidly moved in the fourth bending orientation in the through portion by the returning deformation of the first distal-side traction member resulting from the cancellation of the tension applied to the first distal-side traction member, and the direction of rotation moment acting on the distal-side bending portion is not rapidly changed from the direction to bend the distal-side bending portion in the second bending orientation to the direction to bend the distal-side bending portion in the fourth bending orientation. This prevents the bending skip that causes the distal-side bending portion to be rapidly bent in the fourth bending orientation beyond the non-bent neutral condition.

In an aspect of the present invention, a medical device for multiple bends, includes an insertion portion which is configured to be inserted into a body and which includes a central axis and is configured to extend in an axial direction of the central axis, wherein the inserting portion includes:

a distal-side bending portion configured to bend in a bending orientation which is substantially orthogonal to the central axis,

a proximal-side bending portion which is disposed closer to a proximal side than the distal-side bending portion in the axial direction and which is configured to bend in the bending orientation,

a distal-side traction member which is inserted through the distal-side bending portion and the proximal-side bending portion and which is disposed on the side of the bending orientation, the distal-side traction member including a distal-side fixing portion fixed to the distal end of the distal-side bending portion in the axial direction, the distal-side traction member being pulled toward the proximal end in the axial direction to allow the distal-side bending portion to bend in the bending orientation,

a proximal-side traction member which is inserted through the proximal-side bending portion and which is disposed on the side of the bending orientation, the proximal-side traction member including a proximal-side fixing portion fixed to the distal end of the proximal-side bending portion in the axial direction, the proximal-side traction member being pulled toward the proximal end in the axial direction to allow the proximal-side bending portion to bend in the bending orientation, and

a holding portion which is provided at the distal end of the proximal-side bending portion in the axial direction and which is disposed on the side of the bending orientation and which is configured to hold the distal-side traction member movably back and forth in the axial direction,

the proximal-side fixing portion is disposed at substantially the same position as the distal-side fixing portion in a circumferential direction of the central axis,

the holding portion is disposed at a position different from the proximal-side fixing portion in the circumferential direction,

the distal-side bending portion includes two or more substantially cylindrical bending members which are substantially coaxially arranged in the axial direction and which are rotationally connected to each other,

the two or more bending members includes at least one guide bending member,

the guide bending member includes a guide through portion which is disposed on the side of the bending orientation and which is extending in the axial direction, the distal-side traction member being inserted through the guide through portion movably back and forth in the axial direction and the guide through portion supporting the distal-side traction member, and

the guide through portion is disposed, in the circumferential direction, on a reference line which connects between the position of the distal-side fixing portion and the position of the holding portion and which is configured to extend in the axial direction in such a manner as to be displaced in the circumferential direction.

In the medical device for the multiple bends according to this aspect, the proximal-side fixing portion of the proximal-side traction member at the distal end of the proximal-side bending portion in the axial direction is disposed at substantially the same position in the circumferential direction as the distal-side fixing portion of the distal-side traction member at the distal end of the distal-side bending portion in the axial direction. Therefore, the bending orientation of the distal-side bending portion can exactly correspond to the bending orientation of the proximal-side bending portion, so that the distal end of the insertion portion can be precisely operated. Here, in the guide bending member, the guide through portion is disposed, in the circumferential direction, on the reference line which connects the position of the distal-side fixing portion to the position of the holding portion and which extends in the axial direction in such a manner as to be displaced in the circumferential direction. Thus, excessive interference between the distal-side traction member and the guide through portion is prevented when the distal-side traction member is pulled.

In the aspect of the present invention, in the medical device, the guide through portion extends along the reference line in the guide bending member.

In the medical device for the multiple bends according to this aspect, the guide through portion extends along the reference line in the guide bending member. Thus, excessive interference between the distal-side traction member and the guide through portion is further prevented when the distal-side traction member is pulled.