Patent Description:
Some robots, manipulators or actuators have a joint function unit that enables bending and extension. Examples of such a joint function unit include one described in Patent Document <NUM> which is applied to a surgical instrument.

In this joint function unit, an end effector being a movable-side member is joined to a pipe being a fixed-side member by a bendable member.

One side of an actuation cable being a cord-like member is fixed to the end effector. By pulling the other side of the actuation cable, it is possible to bend the bendable member and displace the end effector with respect to an axis.

However, in the above-mentioned conventional joint function unit, when an external force is applied to the end effector or the like, the bendable member may be forced to bend, and unintended displacement of the end effector may be caused.

<CIT> relates to a medical manipulator including a distal end working unit including a gripper as an end effector, an operating unit for operating the distal end working unit, a coupling interconnecting the distal end working unit and the operating unit, and an attitude changing mechanism for changing an attitude of the distal end working unit. <CIT> relates to control systems and methods for a medical instrument use measurements to determine and control the tensions that actuators apply through instrument transmission systems. <CIT> relates to a manipulator used for lumens to be bent without excessively increasing tension acting on a power transmission member passed through the lumens. <CIT> relates to a surgical tool that has: a treatment section; first and second pulling sections which transmit a pulling force to the treatment section; a power source which generates power for operating the treatment section; and a switching section.

A problem to be solved is that unintended displacement of a movable-side member occurs due to an external force.

The following disclosure serves a better understanding of the present invention. The present invention is a joint function unit in which a movable-side member is supported so as to be displaceable between a bending position and an extension position with respect to a fixed-side member. The joint function unit is most characterized by including: a plurality of cord-like members, having a fixed part fixed to the movable-side member on one side in an axial direction and a supported part supported by the fixed-side member on the other side in the axial direction; and an elastic body, supporting the supported part of the plurality of cord-like members on the fixed-side member, energizing the supported part toward a side opposite to the fixed part in the axial direction, and applying tension to the cord-like member.

According to the present invention, since looseness in the cord-like member is eliminated by the tension applied by the elastic body, and bending rigidity of the joint function unit is improved, even if an external force acts on the movable-side member, unintended displacement of the movable-side member can be suppressed.

The purpose of suppressing unintended displacement of a movable-side member is achieved by applying tension, by an elastic body, to a cord-like member for displacing the movable-side member.

That is, a joint function unit (<NUM>) is provided in which a movable-side member (<NUM>) is supported so as to be displaceable between a bending position and an extension position with respect to a fixed-side member (<NUM>), and the joint function unit (<NUM>) includes a plurality of cord-like members (<NUM>) and an elastic body (<NUM>). The cord-like member (<NUM>) has a fixed part (<NUM>) fixed to the movable-side member (<NUM>) on one side in an axial direction and a supported part (<NUM>) supported by the fixed-side member (<NUM>) on the other side in the axial direction. The elastic body (<NUM>) supports the supported part (<NUM>) of the plurality of cord-like members (<NUM>) on the fixed-side member (<NUM>), energizes the supported part (<NUM>) toward a side opposite to the fixed part (<NUM>) in the axial direction, and applies tension to the cord-like member.

The elastic body (<NUM>) may be configured to be arranged in parallel with the plurality of cord-like members (<NUM>).

The plurality of cord-like members (<NUM>) may each be configured to be inserted through the fixed-side member (<NUM>) between the fixed part (<NUM>) and the supported part (<NUM>). The elastic body (<NUM>) may be configured to be interposed between the supported part (<NUM>) of the plurality of cord-like members (<NUM>) and the fixed-side member (<NUM>).

The elastic body (<NUM>) may be configured to have each of the plurality of cord-like members (<NUM>) inserted therethrough and provided on the same axis.

The joint function unit (<NUM>) may be configured to include a support member (<NUM>) spanning between the supported parts (<NUM>) of the plurality of cord-like members (<NUM>). The elastic body (<NUM>) may be configured to be interposed between the support member (<NUM>) and the fixed-side member (<NUM>).

The joint function unit (<NUM>) may be configured to include a guide part (<NUM>) that guides one of the plurality of cord-like members (<NUM>) and locates the supported part (<NUM>) of the plurality of cord-like members (<NUM>) on the same axis. The elastic body (<NUM>) may be configured to connect between the supported parts (<NUM>) of the plurality of cord-like members (<NUM>).

The fixed-side member (<NUM>) may be configured to include a support part (<NUM>) located on a side opposite to the fixed part (<NUM>) with the supported part (<NUM>) of the plurality of cord-like members (<NUM>) therebetween in the axial direction. The elastic body (<NUM>) may be configured to be interposed between the support part (<NUM>) and the supported part (<NUM>) of the plurality of cord-like members (<NUM>).

The elastic body (<NUM>) may be a coil spring.

The cord-like member (<NUM>) may be a drive wire in which the supported part (<NUM>) is operated in the axial direction to displace the movable-side member (<NUM>) with respect to the fixed-side member (<NUM>). However, the cord-like member may be provided separately from the drive wire.

<FIG> is a perspective view showing a main part of a manipulator to which a joint function unit according to Embodiment <NUM> of the present invention is applied, <FIG> is a sectional view of the manipulator of <FIG>, and <FIG> is a schematic view showing a main part of <FIG>.

In the present embodiment, a manipulator <NUM> is described as an example of a device having a joint function unit <NUM>. The manipulator <NUM> is a forceps for medical use, and may be used not only as a forceps attached to a surgical robot, but also as an endoscopic camera or manual forceps not attached to a surgical robot.

It suffices if the device having the joint function unit <NUM> is a device requiring a joint function, and the device may be a robot, manipulator, actuator or the like in various fields.

The manipulator <NUM> includes a shaft <NUM>, the joint function unit <NUM>, and an end effector <NUM>.

The shaft <NUM> is formed in, for example, a cylindrical shape. The end effector <NUM> is movably supported on a tip side of the shaft <NUM> via the joint function unit <NUM>. The joint function unit <NUM> will be described later.

The end effector <NUM> is a forceps for medical use, and is pivotally supported with respect to a movable part <NUM> of the joint function unit <NUM> to be described later so that a pair of grippers 7a are able to open and close. The end effector <NUM> is connected to a push-pull cable <NUM> inserted through the shaft <NUM> and the joint function unit <NUM>. The grippers 7a are configured to open and close according to an axial movement (advance or retreat) of the push-pull cable <NUM>.

The grippers 7a may be driven by air or the like. The end effector <NUM> may be something other than a forceps, such as scissors, a gripping retractor or a needle driver.

The joint function unit <NUM> includes a base part <NUM>, the movable part <NUM>, a flexible member <NUM>, a drive wire <NUM>, and an elastic body <NUM>.

The base part <NUM> is a columnar body (particularly a circular columnar body) made of resin, metal, or the like. The base part <NUM> is attached to a tip of the shaft <NUM> and constitutes a fixed-side member. The shaft <NUM> also constitutes a portion of the fixed-side member.

The base part <NUM> is not limited to a columnar body, and may be a plate-like body or the like, if in the shape of a wall through which the drive wire <NUM> to be described later is inserted. The base part <NUM> may be in an appropriate form according to the device to which the joint function unit <NUM> is applied.

The movable part <NUM> is a columnar body (particularly a circular columnar body) made of resin, metal, or the like. The movable part <NUM> is attached to the end effector <NUM> and constitutes a movable-side member. The end effector <NUM> also constitutes a portion of the movable-side member.

The movable part <NUM> is not limited to a columnar body, and may be a plate-like body or the like, if being a member allowing the end effector <NUM> to be attached thereto. The movable part <NUM> may also be in an appropriate form according to the device to which the joint function unit <NUM> is applied.

The movable part <NUM> like this is supported by the base part <NUM> so as to be displaceable between a bending position and an extension position with respect to an axial direction by the flexible member <NUM>. The term "axial direction", when used alone, means a direction along an axial center of the joint function unit <NUM>, and may include a slightly inclined direction in addition to a direction strictly parallel to the axial center. The bending position refers to a position where an axis of the movable part <NUM> intersects the axial direction and bending of the joint function unit <NUM> is maximum. The extension position refers to a position where the axis of the movable part <NUM> is along the axial direction. In the extension position, the axis of the movable part <NUM> does not have to be strictly along the axial direction, and may be slightly shifted.

The flexible member <NUM> is arranged in the axial center of the joint function unit <NUM> and displaceably supports the movable part <NUM> on the base part <NUM>. The flexible member <NUM> of the present embodiment includes an inner flexible tube <NUM> and an outer flexible tube <NUM>.

The inner flexible tube <NUM> is a double coil freely bendable with respect to the axial direction, and includes an outer coil portion <NUM> and an inner coil portion <NUM>. The inner flexible tube <NUM> is not limited to one using a double coil if able to displaceably support the movable part <NUM> on the base part <NUM>.

The outer coil portion <NUM> and the inner coil portion <NUM> are coil springs. Both the outer coil portion <NUM> and the inner coil portion <NUM> may be made of metal, resin, or the like. A sectional shape of wires of the outer coil portion <NUM> and the inner coil portion <NUM> is circular. However, the sectional shape is not limited to circular.

The inner coil portion <NUM> has a smaller diameter than the outer coil portion <NUM> and is screwed into the outer coil portion <NUM>. The diameters of the outer coil portion <NUM> and the inner coil portion <NUM> are constant from one end to the other end in the axial direction. However, it is also possible to vary the diameter of the outer coil portion <NUM> in the axial direction.

The outer coil portion <NUM> has a plurality of gaps (pitches) that separate axially adjacent winding portions from each other in the axial direction. A winding portion of the inner coil portion <NUM> is fitted into the plurality of gaps from the inside.

The flexible member <NUM> like this has elasticity enabling bending and restoration of the outer coil portion <NUM> and the inner coil portion <NUM> with respect to the axial direction of the coil shape, and, as a whole, has elasticity enabling bending and restoration with respect to the axial direction.

The flexible member <NUM> is surrounded by the outer flexible tube <NUM> interposed between the base part <NUM> and the movable part <NUM>.

The outer flexible tube <NUM> is composed of a bellows made of a tube having a wavy sectional shape. The outer flexible tube <NUM> is made of metal, resin, or the like. The outer flexible tube <NUM> may also be a coil spring or other tubular body. The outer flexible tube <NUM> is not particularly limited if in the shape of a tube having elasticity.

The outer flexible tube <NUM> elastically bends and restores in response to displacement of the movable part <NUM> with respect to the base part <NUM>. Accordingly, the outer flexible tube <NUM> imparts to the joint function unit <NUM> a linear load characteristic that a load increases as a bending angle increases. The load characteristic will be described later.

Thus, the flexible member <NUM> may, by bending and restoring itself, displace the movable part <NUM> and the end effector <NUM> with respect to the base part <NUM> and the shaft <NUM>. Such displacement is performed by the drive wire <NUM>.

The drive wire <NUM> is a cord-like member made of metal or the like, and is provided in four places in the joint function unit <NUM> in a circumferential direction at intervals of <NUM> degrees in the present embodiment. The drive wires <NUM> facing each other in a radial direction of the joint function unit <NUM> form a pair. Thus, in the present embodiment, two pairs of drive wires <NUM> are provided.

However, it is also possible to omit one pair of drive wires <NUM>, and it suffices if the joint function unit <NUM> includes a plurality of drive wires <NUM>. For example, three drive wires <NUM> may be provided. In this case, the drive wires <NUM> are preferably arranged at intervals of <NUM> degrees in the circumferential direction. The drive wire <NUM>, if being a cord-like member, may be a stranded wire, a nickel-titanium (NiTi) single wire, a piano wire, an articulated rod, a chain, a string, a thread, a rope, or the like.

These drive wires <NUM> bend the joint function unit <NUM> by being pulled in the axial direction, and may be directly or indirectly connected to an operation mechanism (not shown) to be operated in the axial direction. Operation in the axial direction means causing the drive wire <NUM> to advance or retreat in the axial direction.

On one side of each drive wire <NUM> is provided a fixed part <NUM> fixed to the movable part <NUM>. Any fixing means may be applied to the fixed part <NUM>.

Each drive wire <NUM> extends in the axial direction from the fixed part <NUM> and is inserted through the outer flexible tube <NUM> and the base part <NUM>, and has the other side thereof passing through the shaft <NUM>. On the other side of the each drive wire <NUM> is provided a supported part <NUM>.

The supported part <NUM> is provided on the other side of the drive wire <NUM> and is a portion supported by the base part <NUM>. The supported part <NUM> of the present embodiment is a crimping portion at the other end of the drive wire <NUM> and is joined to an end of a connection wire <NUM> by crimping. The supported parts <NUM> of the paired drive wires <NUM> are connected via the connection wire <NUM>. The paired drive wires <NUM> may also be integrally provided in a loop shape.

The connection wire <NUM> has both ends each arranged on the same axis as the other end of the paired drive wires <NUM> via a guide part <NUM> to reach the supported part <NUM>. The guide part <NUM> of the present embodiment is a pulley, and is supported by the shaft <NUM>, an operation mechanism, or the like. It is also possible to omit the connection wire <NUM> and the guide part <NUM> and combine the supported part <NUM> with the operation mechanism.

The elastic body <NUM> supports the supported part <NUM> of the drive wire <NUM> on the base part <NUM> and energizes the supported part <NUM> toward a side opposite to the fixed part <NUM> of the same drive wire <NUM> in the axial direction. Accordingly, the elastic body <NUM> applies tension to each drive wire <NUM> and improves bending rigidity of each drive wire <NUM>.

The elastic body <NUM> of the present embodiment is composed of a coil spring, particularly a compression spring having a pitch. The elastic body <NUM> may be made of metal, resin, or the like, and may have an appropriate shape depending on an elastic modulus or the like. For example, in the case of rubber or the like, the elastic body may have a columnar shape or tubular shape.

The elastic body <NUM> is interposed between the supported part <NUM> of the drive wire <NUM> and the base part <NUM>. Specifically, the elastic body <NUM> is provided for each drive wire <NUM> and has each drive wire <NUM> inserted therethrough and arranged on the same axis. Both ends of the elastic body <NUM> respectively abut against the base part <NUM> and the supported part <NUM>.

Thus, the elastic body <NUM> is configured to be arranged in parallel with the drive wire <NUM> so as to exert elastic force in the axial direction. The term "parallel" used herein refers to arranging the elastic body <NUM> so that the axial direction and a direction in which the elastic force acts are parallel. However, the two directions do not have to be strictly parallel, and the term "parallel" may also include a case where one of the two directions is slightly inclined with respect to the other. The elastic body <NUM> between the supported part <NUM> and the base part <NUM> may be omitted, and the guide part <NUM> may be configured to be pulled by the elastic body <NUM>.

Each elastic body <NUM> has an axial dimension in a free state set smaller than an axial dimension between the supported part <NUM> and the base part <NUM>. Hence, each elastic body <NUM> is compressed between the supported part <NUM> and the base part <NUM> according to a dimensional difference. Due to this compression, a load is applied to each elastic body <NUM> and tension corresponding to the load is applied to the drive wire <NUM>.

The elastic body <NUM> like this, together with the flexible member <NUM>, is able to impart to the joint function unit <NUM> the linear load characteristic that a load increases as a bending angle increases. The load characteristic will be described later.

(A) and (B) of <FIG> are conceptual views of the manipulator of <FIG>, in which (A) of <FIG> shows a normal state and (B) of <FIG> shows a bending state.

In the present embodiment, in the normal state in which the drive wire <NUM> is not operated, tension is applied by the elastic body <NUM> to the drive wire <NUM>, eliminating looseness and improving bending rigidity in the drive wire <NUM>.

Hence, even if an external force F is applied to the end effector <NUM> or the movable part <NUM> of the joint function unit <NUM>, both being the movable-side member, in a direction (left-right direction in (A) of <FIG>) intersecting the axial direction, unintended displacement of the movable part <NUM> and the end effector <NUM> can be suppressed.

When an operator such as a doctor operates the manipulator <NUM>, the joint function unit <NUM> is bent by pulling any one of the drive wires <NUM>. By combining different pairs of drive wires <NUM> and pulling the same, it is possible to bend the joint function unit <NUM><NUM> degrees in all directions. Accordingly, the end effector <NUM> can be oriented in a desired direction.

When any one of the drive wires <NUM> is pulled and the joint function unit <NUM> is bent, as in (B) of <FIG>, in an inner portion of the bend, the supported part <NUM> of the drive wire <NUM> (referred to as inner wire <NUM>) is displaced so as to widen a space between itself and the base part <NUM> in the axial direction. Accordingly, the fixed part <NUM> of the inner wire <NUM> is pulled toward the base part <NUM> side.

At this time, since the joint function unit <NUM> is bent and this state is maintained, the inner wire <NUM> is subjected to tension greater than that in the normal state. As a result, the inner wire <NUM> is improved in bending rigidity.

On the other hand, in an outer portion of the bend, as the drive wire <NUM> (referred to as outer wire <NUM>) paired with the inner wire <NUM> is pulled by the fixed part <NUM> as bending occurs, the supported part <NUM> is displaced and pushed to narrow the space between itself and the base part <NUM> in the axial direction.

At this time, the elastic body <NUM> coaxial with the outer wire <NUM> is compressed against its own elastic force, and the elastic body <NUM> coaxial with the inner wire <NUM> attempts to extend between the supported part <NUM> and the base part <NUM> by its own elastic force. Hence, even if the supported part <NUM> is displaced toward the base part <NUM> side in a direction of losing tension, the outer wire <NUM> is given tension without loosening. As a result, the outer wire <NUM> is also improved in bending rigidity, together with the inner wire <NUM>.

In this way, in the manipulator <NUM> of the present embodiment, even during bending in which the drive wire <NUM> is operated, the bending rigidity of the drive wire <NUM> is improved on the inside and outside of the bend.

Hence, even if the external force F is applied to the end effector <NUM> or the movable part <NUM> of the joint function unit <NUM> in a direction (up-down direction in (B) of <FIG>) intersecting the axial direction, unintended displacement of the end effector <NUM> can be suppressed.

An operation force for compressing the elastic body <NUM> coaxial with the outer wire <NUM> can be assisted by the elastic force for extending the elastic body <NUM> coaxial with the inner wire <NUM>. Hence, an increase in overall operation force for bending the joint function unit <NUM> can be suppressed, and the joint function unit <NUM> can be easily bent.

<FIG> is a graph showing a relationship between displacement amount with respect to external force and load of an elastic body.

<FIG> is obtained by measuring a displacement amount of the end effector <NUM> when the external force F of 2N is applied to the end effector <NUM> in a direction intersecting the axial direction in the normal state. The load in <FIG> indicates a load applied to the elastic body <NUM> in the normal state.

As in <FIG>, during from a state in which no load is applied to the elastic body <NUM> until the magnitude of the load of the elastic body <NUM> becomes equal to the external force F, a ratio of decrease in the displacement amount of the end effector <NUM> is large. On the other hand, even if the load of the elastic body <NUM> exceeds the external force F, the ratio of decrease in the displacement amount is reduced. As the load of the elastic body <NUM> is increased, the bending rigidity of the drive wire <NUM> is improved and it becomes difficult to bend the joint function unit <NUM>. Thus, the load of each elastic body <NUM> is preferably set equivalent to the assumed external force F.

<FIG> is a graph showing a relationship between load and bending angle of a joint function unit. <FIG> shows a load of the joint function unit <NUM>, the flexible member <NUM> and the drive wire <NUM> when the paired drive wires <NUM> are operated to bend the joint function unit <NUM> from a bending angle of <NUM> degree to the bending angle of <NUM> degrees and then return the joint function unit <NUM> to the bending angle of <NUM> degree.

In the present embodiment, the elastic body <NUM> and the flexible member <NUM> have a linear load characteristic in which the load increases as the bending angle increases, and the joint function unit <NUM> has a linear load characteristic in which the elastic body <NUM> and the flexible member <NUM> are combined.

Thus, the joint function unit <NUM> has excellent load resistance and bendability. By adjusting the load characteristic of the elastic body <NUM> and the flexible member <NUM>, the load characteristic of the joint function unit <NUM> can be adjusted and set.

As described above, in the present embodiment, the joint function unit <NUM> is provided in which the movable part <NUM> is supported so as to be displaceable between the bending position and the extension position with respect to the base part <NUM>. The joint function unit <NUM> includes: a plurality of drive wires <NUM>, having the fixed part <NUM> fixed to the movable part <NUM> on one side in the axial direction and the supported part <NUM> supported by the base part <NUM> on the other side in the axial direction; and the elastic body <NUM>, supporting the supported part <NUM> of the plurality of drive wires <NUM> on the base part <NUM>, energizing the supported part <NUM> toward a side opposite to the fixed part <NUM> in the axial direction, and applying tension to the drive wire <NUM>.

Thus, in the present embodiment, since looseness in the drive wire <NUM> is eliminated and bending rigidity is improved in response to the tension applied by the elastic body <NUM>, even if the external force F acts on the movable part <NUM> or the end effector <NUM>, unintended displacement of the movable part <NUM> or the end effector <NUM> can be suppressed.

Since the elastic body <NUM> is arranged in parallel with the plurality of drive wires <NUM>, the elastic body <NUM> is able to easily and reliably apply tension to the drive wires <NUM>.

The plurality of drive wires <NUM> are each inserted through the base part <NUM> between the fixed part <NUM> and the supported part <NUM>. The elastic body <NUM> is interposed between the supported part of the plurality of drive wires <NUM> and the base part <NUM>.

Thus, in the present embodiment, tension can be applied to the drive wire <NUM> by a simple configuration.

Since the elastic body <NUM> has each of the plurality of drive wires <NUM> inserted therethrough and provided on the same axis, the elastic body <NUM> can be held between the supported part <NUM> and the base part <NUM> by a simple configuration.

<FIG> is a conceptual view showing a manipulator to which a joint function unit according to Embodiment <NUM> of the present invention is applied. In Embodiment <NUM>, the configurations corresponding to those of Embodiment <NUM> are assigned the same reference numerals, and repeated descriptions are omitted.

In Embodiment <NUM>, a single elastic body <NUM> is used for the paired drive wires <NUM> of the joint function unit <NUM>. Specifically, a support member <NUM> is provided spanning between the supported parts <NUM> of the paired drive wires <NUM>, and the elastic body <NUM> is interposed between the support member <NUM> and the base part <NUM>. The others are the same as those of Embodiment <NUM>.

The support member <NUM> is a plate-like body provided spanning between the supported parts <NUM> of the paired drive wires <NUM>. The drive wire <NUM> is inserted through the support member <NUM>. The support member <NUM> is pressed against the supported part <NUM> by the elastic body <NUM>.

In Embodiment <NUM>, the same effects as those of Embodiment <NUM> can be achieved.

In Embodiment <NUM>, the paired drive wires <NUM> of the joint function unit <NUM> are connected by the elastic body <NUM>. Specifically, the guide part <NUM> is provided that guides one of the paired drive wires <NUM> and locates the supported part <NUM> of the paired drive wires <NUM> on the same axis. The elastic body <NUM> connects between the supported parts <NUM> of the paired drive wires <NUM>. The others are the same as those of Embodiment <NUM>.

The guide part <NUM> is configured in the same manner as in Embodiment <NUM>. One of the paired drive wires <NUM> is formed longer than the other of the paired drive wires <NUM>, and is wound around the guide part <NUM> so that the supported parts <NUM> of two drive wires <NUM> are located on the same axis.

In the present embodiment, a pair of elastic bodies <NUM> are provided and are each joined to the supported part <NUM>. The elastic bodies <NUM> are connected by a pair of connecting members <NUM>. The connecting member <NUM> is a member to which the elastic body <NUM> is integrally joined. These connecting members <NUM> are engaged by a clamping part 37a clamping a drive shaft <NUM>.

The elastic body <NUM> energizes the connecting member <NUM> in a direction in which the drive shaft <NUM> is clamped by the clamping part 37a, and holds the state in which the drive shaft <NUM> is clamped by the clamping part 37a. The drive shaft <NUM> is connected to an operation mechanism and is displaced in the axial direction in response to an operation of the operation mechanism.

Thus, in Embodiment <NUM>, the same effects as those of Embodiment <NUM> can be achieved. Embodiment <NUM>.

<FIG> is a conceptual view showing a manipulator to which a joint function unit according to Embodiment <NUM> of the present invention is applied, (A) of <FIG> is a conceptual view showing a modification of Embodiment <NUM>, and (B) of <FIG> is a conceptual view of (A) of <FIG> as seen from a direction <NUM> degrees different from that of (A) of <FIG>. In Embodiment <NUM>, the configurations corresponding to those of Embodiment <NUM> are assigned the same reference numerals, and repeated descriptions are omitted.

In Embodiment <NUM>, the flexible member <NUM> of the joint function unit <NUM> is composed of a universal joint. The others are the same as those of Embodiment <NUM>. The flexible member <NUM> is not limited to a universal joint if composed of a plurality of mutually swingable members that are connected to each other. For example, as in (A) and (B) of <FIG>, it is also possible to swingably connect a first swinging member 40a with respect to the base part <NUM>, swingably connect a swinging member 40b in an orthogonal direction with respect to the first swinging member 40a, and join the movable part <NUM> to the swinging member 40b.

In Embodiment <NUM>, the same effects as those of Embodiment <NUM> can be achieved. In Embodiment <NUM>, a linear load characteristic can be imparted by the elastic body <NUM> to the joint function unit <NUM> that does not have a linear load characteristic.

In Embodiment <NUM>, the elastic body <NUM> is provided between a support part <NUM> of the shaft <NUM> as the fixed-side member and the supported part <NUM> of the drive wire <NUM>. Specifically, the shaft <NUM> includes the support part <NUM> located on a side opposite to the fixed part <NUM> with the supported part <NUM> of each drive wire <NUM> therebetween in the axial direction. The elastic body <NUM> is interposed between the support part <NUM> and the supported part <NUM>. In Embodiment <NUM>, the connection wire <NUM> and the guide part <NUM> are omitted, and the supported part <NUM> is combined with an operation mechanism. By this combination, tension is applied to the drive wire <NUM> in the present embodiment. However, the connection wire <NUM> and the guide part <NUM> may be provided as in Embodiment <NUM>. The others are the same as those of Embodiment <NUM>.

The support part <NUM> may be provided at an end of the shaft <NUM> or inside the shaft <NUM>. The support part <NUM> may have any shape if able to support the elastic body <NUM>. The elastic body <NUM> of the present embodiment is a tension spring.

Claim 1:
A joint function unit (<NUM>) in which a movable-side member (<NUM>, <NUM>) is supported so as to be displaceable between a bending position and an extension position with respect to a fixed-side member (<NUM>), the joint function unit (<NUM>) comprising:
a plurality of drive wires (<NUM>), each having a fixed part (<NUM>) fixed to the movable-side member (<NUM>, <NUM>) on one side in an axial direction and a supported part (<NUM>) supported by the fixed-side member (<NUM>) on the other side in the axial direction; and
an elastic body (<NUM>), configured to support the supported parts (<NUM>) of the plurality of drive wires (<NUM>) on the fixed-side member (<NUM>), energize the supported parts (<NUM>) toward a side opposite to the fixed parts (<NUM>) in the axial direction, and apply tension to the plurality of drive wires (<NUM>),
the joint function unit (<NUM>) wherein
each of the plurality of drive wires (<NUM>) is inserted through the fixed-side member (<NUM>) between the fixed part (<NUM>) and the supported part (<NUM>), and
the elastic body (<NUM>) is interposed between the supported parts (<NUM>) of the plurality of drive wires (<NUM>) and the fixed-side member (<NUM>).