A manipulator including: an end effector movable about a joint; a motor configured to generate force so as to move the end effector; a wire for transmitting the force from the motor to the end effector; a guide member connected between the end effector and motor. The guide member including: a guide tube comprising at least one lumen extended in a longitudinal direction, the lumen configured to guide the wire; and an outer sheath configured to cover the guide tube in a longitudinal direction and to move relative to the motor in the longitudinal direction, the outer sheath having a rigidity higher than the guide tube. The manipulator further including an adjusting mechanism configured to adjust a position of the proximal end section of the outer sheath relative to the motor in the longitudinal direction of the guide tube so as to adjust a tensile-force generated on the wire.

BACKGROUND

Field

The present disclosure relates to manipulators.

Prior Art

A known surgical device in the related art uses a wire to drive a bending section or a movable section, such as forceps, disposed at the distal end of a flexible insertion section (for example, see Publication of Japanese Patent No. 5542288).

The surgical device according to Japanese Patent No. 5542288 includes a constant-force spring that applies a fixed initial tensile force to the wire so as to prevent the tensile force of the wire, which extends internally through the flexible insertion section, from changing due to bending of the flexible insertion section.

SUMMARY

Accordingly, a manipulator is provided. The manipulator comprising: an end effector movable about a joint; a motor configured to generate force so as to move the end effector about the joint; a wire configured to transmit the force from the motor to the end effector; a guide member connected between the end effector and motor, the guide member comprises: a guide tube comprising at least one lumen extended in a longitudinal direction, the at least one lumen configured to guide the wire; and an outer sheath configured to cover the guide tube in a longitudinal direction and to move relative to the motor in the longitudinal direction of the guide tube, the outer sheath having a rigidity higher than a rigidity of the guide tube; and an adjusting mechanism configured to adjust a position of the proximal end section of the outer sheath relative to the motor in the longitudinal direction of the guide tube so as to adjust a tensile-force generated on the wire.

DETAILED DESCRIPTION

A manipulator1according to an embodiment will be described below with reference to the drawings.

For example, as shown inFIG. 1, the manipulator1according to this embodiment includes a long guide member2that is elongate and flexible and that is to be inserted into the body cavity of a patient through a channel of an endoscope to be inserted into the body cavity of the patient, a movable section3(end effector) disposed at the distal end of the long guide member2, a driving section4that is disposed at the proximal end of the long guide member2and that actuates the movable section3, wires (tensile-force transmitting members)5that transmit a driving force generated by the driving section4as a tensile force to the movable section3, and a tensile-force adjusting mechanism6that adjusts the tensile force of the wires5.

The movable section3includes a treatment section7, such as forceps, to be applied to an affected site inside the body and also includes at least one joint section8that supports the treatment section7. For simplifying the description, the example shown in the drawings illustrates a case where the joint section8has a single swiveling joint that causes the treatment section7to swivel about an axis orthogonal to the longitudinal axis of the long guide member2.

The long guide member2includes a multi-lumen tube (guide tube)11having two lumens10through which two wires5extend, a coil tube (outer sheath)12disposed so as to cover the outer peripheral surface of the multi-lumen tube11, and a movable end member (proximal end section)13that is fixed to the proximal end of the coil tube12and that is movable in the longitudinal direction of the multi-lumen tube11.

The multi-lumen tube11is composed of a readily-deformable flexible resin material having low rigidity. In contrast, the coil tube12is composed of a metallic material having higher rigidity than the multi-lumen tube11. As shown inFIG. 1, the coil tube12is a tightly-wound coil in which elemental wires are closely in contact with each other without gaps therebetween in a state where the long guide member2extends straight.

The driving section4includes a motor unit15equipped with a motor14, and also includes a manipulator-side driving section16attached to the proximal end of the multi-lumen tube11. The motor unit15and the manipulator-side driving section16are attachable to and detachable from each other. The manipulator-side driving section16includes a pulley (power converting section)17around which the two wires5are routed, and also includes a housing18that rotatably supports the pulley17.

When the manipulator-side driving section16is coupled to the motor unit15, a shaft9of the motor14in the motor unit15and the pulley17of the manipulator-side driving section16are coupled to each other by means of, for example, a spline gear. Thus, a rotational driving force of the motor14is converted into a tensile force of either one of the wires5routed around the pulley17, depending on the rotational direction of the pulley17. Then, the joint section8is driven in either direction by the tensile force transmitted by the wire5.

The distal end of the multi-lumen tube11is fixed to the joint section8, whereas the proximal end of the multi-lumen tube11is fixed to the housing18of the manipulator-side driving section16. The distal end of the coil tube12is also fixed to the joint section8.

Furthermore, as shown inFIG. 1, in the state where the long guide member2extends straight, a gap is formed between the movable end member13and the housing18in the longitudinal direction of the multi-lumen tube11.

The tensile-force adjusting mechanism6includes a slider20that is provided in the motor unit15and that has a connection section19to be fixed to the movable end member13when the motor unit15is coupled to the manipulator-side driving section16, and also includes a movement mechanism21that moves the slider20in the longitudinal direction of the multi-lumen tube11.

The movement mechanism21is, for example, a linear motion mechanism equipped with a motor21aand a ball screw (shaft)21b.

For example, as shown inFIGS. 2A and 2B, the connection section19may employ a substantially cross-sectionally C-shaped gripping member22that is brought into contact with the movable end member13, which has a cylindrical shape, from the radially outer side thereof and accommodates the movable end member13so as to cover substantially half the circumference of the outer peripheral surface of the movable end member13. In the drawings, reference sign23denotes a coating composed of a friction-increasing material.

When the connection section19accommodates the movable end member13, the movable end member13is tightened radially inward by the elasticity of the connection section19, and the connection section19becomes secured to the movable end member13by friction in the contact area between the two.

The following description relates to a case where medical treatment is performed inside the body of the patient by using the manipulator1according to this embodiment having the above-described configuration.

The manipulator1according to this embodiment is inserted through a channel of an insertion section of an endoscope inserted into the body cavity from outside the body of a patient, starting from the movable section3at the distal end. The movable section3is then made to protrude from an opening of a forceps channel in a distal-end surface of the insertion section of the endoscope disposed inside the body.

In this case, the body cavity is often curved, so that the insertion section of the endoscope and the channel provided at the insertion section are inserted into the body cavity by being bent in conformity to the shape of the body cavity. Therefore, when the manipulator1is to be inserted through such a channel, the manipulator1would be inserted while bending the long guide member2in conformity to the channel.

In the case where the long guide member2of the manipulator1according to this embodiment is to be bent, the multi-lumen tube11having high flexibility and disposed along the center is bent. Since the opposite ends of the multi-lumen tube11are fixed to the movable section3and the driving section4, if the multi-lumen tube11is bent without increasing or decreasing the length along the center line thereof, the lumens10formed in the multi-lumen tube11do not significantly expand or contract. As a result, the path length of the wires5disposed within the lumens10do not significantly change.

When the multi-lumen tube11is bent, the coil tube12covering the outer periphery thereof is also bent. Because the coil tube12is composed of a material having rigidity high enough for the multi-lumen tube11, when the long guide member2is bent, the length of an area thereof disposed at the radially inner side of the bend does not change such that the elemental wires are kept closely in contact with each other, whereas the elemental wires in an area disposed at the radially outer side of the bend become separated by an increased distance.

As shown inFIG. 4A, in the manipulator1according to this embodiment, the proximal end of the coil tube12is fixed to the movable end member13that is movable relative to the housing18of the driving section4in the longitudinal direction of the multi-lumen tube11. Therefore, as shown inFIG. 4B, when the long guide member2is bent, the movable end member13moves relative to the housing18, thus causing the proximal end of the coil tube12to move toward the driving section4. Specifically, when the long guide member2is bent, the proximal end of the coil tube12shifts so as to close the gap between the movable end member13and the housing18since the proximal end of the coil tube12is not fixed. As a result, the length of the multi-lumen tube11is maintained, and the path length of the wires5is prevented from increasing.

Subsequently, in this state where the long guide member2is bent and the movable section3protrudes from the distal end of the insertion section of the endoscope near the affected site, the manipulator-side driving section16included in the driving section4is attached to the motor unit15. Consequently, as shown inFIG. 3, the shaft9of the motor14included in the motor unit15becomes connected to the pulley17of the manipulator-side driving section16, and the connection section19provided in the slider20of the tensile-force adjusting mechanism6becomes fixed to the movable end member13.

When the motor14of the motor unit15is actuated in this state, the rotational force of the motor14is transmitted to the pulley17and is converted into a tensile force of the wires5by the pulley17. The tensile force of either one of the wires5increases so that the movable section3is operated.

In this case, in the manipulator1according to this embodiment, the connection section19provided in the slider20of the tensile-force adjusting mechanism6is fixed to the movable end member13of the coil tube12, so that, by applying a tensile force to the wire5for driving the movable section3, a compression force applied to the multi-lumen tube11can be reduced.

Furthermore, by moving the slider20by actuating the motor21aof the movement mechanism21, the position of the proximal end of the coil tube12relative to the multi-lumen tube11can be adjusted in the longitudinal direction of the multi-lumen tube11. Specifically, by moving the slider20toward the distal end of the multi-lumen tube11, the movable section3is made to advance forward so that the initial tensile force applied to the wire5can be increased. In contrast, by moving the slider20toward the proximal end of the multi-lumen tube11, the movable section3is made to retract so that the initial tensile force applied to the wire5can be reduced.

Accordingly, the manipulator1according to this embodiment is advantageous in that the position of the proximal end of the coil tube12can be adjusted by actuating the movement mechanism21, so that the tensile force of the wire5can be adjusted and an appropriate tensile force can be applied thereto in accordance with the bent state of the long guide member2, whereby the movable section3can be operated with high accuracy.

Although the multi-lumen tube11is composed of a material having low rigidity in this embodiment, the rigidity of the long guide member2itself is increased by means of the coil tube12that covers the outer periphery of the multi-lumen tube11. Therefore, by causing a force to act on the proximal end of the coil tube12in the longitudinal direction, the entire manipulator1can be made to advance or retract. In addition, by applying torque to the proximal end of the coil tube12about the longitudinal axis, the movable section3at the distal end can be rotated about the longitudinal axis.

In addition to the method of applying torque directly to the proximal end of the coil tube12, the method for applying torque to the coil tube12may involve providing a rotation stopper that regulates displacement of the movable end member13in the circumferential direction between the housing18and the movable end member13and transmitting the torque to be applied to the housing18to the coil tube12via the rotation stopper, as shown inFIG. 5.

The rotation stopper may be constituted by providing the housing18with a long hole24extending in the longitudinal direction of the multi-lumen tube11and providing the movable end member13with a pin25fitted in the long hole24. When the slider20is to move in the longitudinal direction of the multi-lumen tube11, the long hole24is moved relative to the pin25. When torque is applied to the housing18, torque acting around the longitudinal axis of the multi-lumen tube11can be transmitted in accordance with the engagement between the pin25and the long hole24.

As shown inFIGS. 6A and 6B, the connection section19that connects the slider20to the movable end member13provided at the proximal end of the coil tube12may have a structure in which an outer ring of a bearing26fixed to the movable end member13is engaged with the inner side of the C-shaped gripping member22such that the movable end member13is prevented from moving in the longitudinal direction of the multi-lumen tube11while the movable end member13is allowed to rotate relative to the slider20.

Furthermore, as shown inFIGS. 7A and 7B, the connection section19may be constituted of a plurality of grooves27arranged side-by-side on the slider20in the moving direction thereof and a protrusion28provided on the movable end member13. When the manipulator-side driving section16is attached to the motor unit15, the protrusion28of the movable end member13is engaged with any of the grooves27in the slider20so that relative movement between the movable end member13and the slider20can be restricted at a freely-chosen position. The protrusion28and the grooves27may be interchanged with each other.

As an alternative to this embodiment in which the proximal end of the multi-lumen tube11is fixed to the housing18, the proximal end of the multi-lumen tube11may be fixed to the slider20, and a compression spring29may be disposed between the housing18and the slider20, as shown inFIG. 8A.

According to this configuration, when the long guide member2is bent, the compression spring29is compressed and the slider20is moved, as shown inFIG. 8B.

In this case, the proximal end of the multi-lumen tube11fixed to the slider20is also moved in accordance with the movement of the slider20. Because the multi-lumen tube11is formed of a resin tube having low rigidity, the multi-lumen tube11is expanded when the proximal end thereof is moved. However, by moving the proximal end by the expanded amount, an increase in the path length of the wires5can be prevented.

Furthermore, in this case, the multi-lumen tube11may extend into the housing18of the driving section4, as shown inFIGS. 9A and 9B.

In this embodiment, the multi-lumen tube11has the plurality of lumens10formed straight in the longitudinal direction of the multi-lumen tube11. However, the embodiment is not limited to this configuration. As shown inFIG. 10, lumens30that are twisted about the longitudinal axis of the multi-lumen tube11may be used.

Accordingly, even if there is a large difference in radii of curvature when a thick multi-lumen tube11is used and bent, a change in the length of the lumens30caused by the bending process can be suppressed, thereby preventing the path length of the wires5from changing.

Although the manipulator-side driving section16and the motor unit15are attachable to and detachable from each other in this embodiment, the two may be configured as a single unit. In this case, when the manipulator1is to be inserted through the channel of the endoscope, the slider20may be movable, and the tensile force may be adjusted by moving the slider20by using the motor21aafter the insertion process.

Furthermore, as an alternative to the above example in which the movable end member13is moved by the movement mechanism21equipped with the motor21aand the linear motion mechanism, the movable end member13may be moved by means of a manual movement mechanism21, such as a dial or a handle.

Although the coil tube12is exemplified as an outer sheath in this embodiment, the embodiment is not limited to this configuration. A freely-chosen type of a flexible tube may be used so long as the tube has higher rigidity than the multi-lumen tube11.

Furthermore, in this embodiment, a pressure sensor (not shown) that detects a pressing force applied to the ball screw21bby the movement mechanism21may be provided.

Accordingly, in a state where the slider20is connected to the movable end member13, the motor21aof the movement mechanism21is actuated so that when the movable end member13is pressed, the pressing force detected by the pressure sensor provided in the ball screw21bincreases. Thus, when the pressing force reaches a predetermined pressure, the operation of the movement mechanism21is stopped, so that the tensile force of the wires5can be properly adjusted.

Although preferred embodiments have been described above, the present invention is not limited to the embodiments and modifications thereof. Additions, omissions, substitutions and other changes in the structure are possible without departing from the spirit of the present invention. The present invention is not limited by the foregoing description but is limited only by the scope of the appended claims.

REFERENCE SIGNS LIST