There are known endoscopes, catheters, or manipulators employing a system in which a bending portion or a movable portion such as forceps or the like that is disposed at a distal end of an inserted portion is driven by using a wire (for example, see Patent Literatures 1 to 8).
Patent Literature 1 discloses a flexible manipulator in which the diameter is reduced and a cost reduction is achieved by eliminating an insulation film and a coil sheath by guiding wires, which are used to drive a movable portion, such as forceps or the like disposed at a distal end of a flexible inserted portion, so as to pass through a lumen formed straight along the longitudinal direction of a multi-lumen tube disposed in the inserted portion.
In addition, Patent Literature 2 discloses a rigid manipulator in which a plurality of wires that pass through a joint, which is disposed at a distal end of a rigid inserted portion, and that are used to drive a movable portion, such as forceps or the like, disposed farther on the distal-end side than the joint is, are individually made to pass through a plurality of sheaths, which pass through the inserted portion and the joint, and the sheaths are twisted at the position of the joint, thus compensating for the differences in the path lengths caused by flexing of the joint.
In addition, in order to prevent the flexural rigidity of a multi-lumen tube having partitions that radially section the interior of the tube from becoming non-uniform depending on the positions of the partitions, Patent Literature 3 discloses a medical tube in which the partitions are twisted along the longitudinal direction.
In addition, in order to enhance the flexing performance of a flexing portion disposed at a distal end of a flexible inserted portion, Patent Literature 4 discloses a catheter tube having multiple lumens in which the lumens through which a wire to passes through are twisted by 90° in the inserted portion and the flexing portion.
In addition, in order to prevent a wire guide disposed inside a flexible pipe from pressing or damaging other built-in objects inside the flexible pipe, Patent Literature 5 discloses an endoscope inserted portion in which a wire guide formed of a coil pipe that is twisted, inside the flexible pipe, about the axis of the flexible pipe is secured to an inner surface of the flexible pipe.
In addition, Patent Literature 6 discloses an endoscope in which a bending-manipulation wire passes through straight along the longitudinal direction inside a lumen disposed at the center in a radial direction, and, inside a lumen disposed in the surrounding area thereof in a spiraling manner, a signal line or the like passes through.
In addition, Patent Literature 7 discloses an endoscope in which bending-manipulation wires pass through lumens that are provided side-by-side along the longitudinal direction of a multi-lumen tube.
Furthermore, Patent Literature 8 discloses a catheter in which a lumen through which a bending-manipulation wire passes is disposed along the longitudinal axis of the catheter in a spiraling manner.
With the flexible manipulator of Patent Literature 1, because the lumens that guide the wires is formed straight along the longitudinal direction of the inserted portion, depending on the bending direction of the inserted portion, the path lengths of the two wires for manipulating the movable portion become different, and the movable portion is moved in an unintended direction when one wire tenses while making the other relaxed.
Patent Literature 2 relates to a joint portion of a rigid manipulator, and wire paths are assumed only for a bending portion that is actively bent in a set bending direction.
The object of Patent Literature 3 is to enhance the flexibility of a medical tube, and there is no description of wires for driving a movable portion.
Patent Literature 4 relates to wire paths for facilitating bending in a direction with a low flexural rigidity, and the wire paths are assumed only for a bending portion that is actively bent in a set bending direction.
Patent Literature 5 provides merely description of securing a wire guide formed of a coil pipe so as not to damage other built-in objects.
In Patent Literatures 6 and 7, because the path of the wire for driving the movable portion is formed straight along the longitudinal direction of the inserted portion, between the case in which the inserted portion is straight and the case in which the inserted portion is bent, there is a large change in frictional forces generated between the wire and the lumen, thus making the controllability poor.
Patent Literature 8 provides merely description of flexing and turning a distal end by compressing the catheter in accordance with the tensile forces in the wires.