JP7540894B2 - Torque transmission tool - Google Patents

Description

The technology disclosed in this specification relates to a torque transmission device that transmits torque to a medical instrument.

For example, a torque transmission device that transmits torque to a medical instrument such as a dilator is known. The torque transmission device includes an inner tube that holds the base end portion of the dilator, and an outer tube that covers the outer periphery of the inner tube, and has a torque limiter function (see, for example, Patent Document 1). The torque limiter function is such that when the rotational torque applied to the outer tube by a rotational operation (hereinafter referred to as "operation torque") is equal to or less than a threshold value, the inner tube rotates in conjunction with the rotation of the outer tube, and the operation torque is transmitted to the medical instrument, and when the operation torque exceeds the threshold value, the inner tube rotates freely relative to the outer tube, and the operation torque is not transmitted to the medical instrument.

For example, a doctor or other technician inserts the tip of a dilator into a narrowed or blocked area (hereinafter referred to as the "lesion") formed in a body cavity such as a bile duct, and rotates the outer tube of a torque transmission device that holds the base end of the dilator. This transmits the operating torque from the outer tube to the inner tube, and the tip of the dilator advances while rotating, pushing open and expanding the hole previously formed in the lesion by the guidewire. When the operating torque exceeds a threshold, the torque limiter function prevents the operating torque from being transmitted from the outer tube to the inner tube, and the tip of the dilator stops rotating. This prevents the application of an excessively large operating torque from causing pain inside the body cavity or damaging the medical instrument.

U.S. Pat. No. 8,231,569

In the conventional torque transmission device described above, the torque limiter function operates at the same threshold value for both rotation directions of the outer cylinder in one direction and in the opposite direction. For this reason, conventional torque transmission devices cannot transmit to a medical instrument an operating torque that exceeds the threshold value of the torque limiter function. As a result, for example, if a medical instrument becomes caught in a body cavity, sufficient operating torque cannot be transmitted to the medical instrument, which may make it difficult to remove the medical instrument.

This specification discloses a technology that can solve the above-mentioned problems.

The technology disclosed in this specification can be realized, for example, in the following forms:

(1) The torque transmission device disclosed in this specification is a torque transmission device that transmits torque to a medical instrument, and includes a columnar body that holds the medical instrument, and an outer tube that covers the outer periphery of the columnar body, and a first member that is one of the columnar body and the outer tube, has a recess formed therein, and a second member that is the other of the columnar body and the outer tube, has a protrusion that engages with the recess. When the outer tube is rotated in a first rotation direction around the axis of the outer tube, if the rotational torque applied to the outer tube is equal to or less than a threshold value, the engagement state between the protrusion and the recess is maintained, and when the rotational torque applied to the outer tube exceeds the threshold value, the engagement state is released, and when the outer tube is rotated in a second rotation direction opposite to the first rotation direction, the engagement state is maintained even if the rotational torque applied to the outer tube exceeds the threshold value.

In this torque transmission device, when the outer tube is rotated in the first rotation direction, if the rotational torque applied to the outer tube (hereinafter referred to as "operation torque") is equal to or less than a threshold value, the engagement state between the convex portion and the concave portion is maintained. Therefore, the operation torque is transmitted from the outer tube to the columnar body, and the medical instrument rotates. When the operation torque exceeds the threshold value, the engagement state is released, so that the operation torque is no longer transmitted from the outer tube to the columnar body, and the rotation of the medical instrument stops. Therefore, when the outer tube is rotated in the first rotation direction, it is possible to prevent excessive operation torque from being transmitted to the medical instrument. On the other hand, when the outer tube is rotated in a second rotation direction opposite to the first rotation direction, the engagement state is maintained even if the operation torque exceeds the threshold value. Therefore, the rotation of the medical instrument continues. Therefore, for example, if the medical instrument is caught in a predetermined place inside the body, the medical instrument can be removed from the predetermined place by rotating the outer tube in the second rotation direction with an operation torque greater than the threshold value to rotate the medical instrument. As a result, this torque transmission device can maintain the torque limiter function in one rotation direction while allowing the medical instrument to be rotated with a rotational torque that exceeds the torque limiter threshold in the other rotation direction.

(2) In the torque transmission device, the protrusion may be elastic, and in the cross section of the outer tube, the tip portion of the protrusion may extend in a direction inclined toward the first rotation direction with respect to a reference direction from the axis of the columnar body toward the recess. In this torque transmission device, the tip portion of the protrusion extends in a direction inclined toward the first rotation direction with respect to a reference direction from the axis of the columnar body toward the recess. Therefore, when the outer tube is rotated in the first rotation direction, if the operation torque is equal to or less than a threshold value, the engagement state between the protrusion and the recess is maintained, and the medical instrument rotates. When the operation torque exceeds the threshold value, the tip portion of the protrusion is pressed against the inner wall surface of the recess and elastically deforms toward the columnar body, and the engagement state is released by removing from the recess, and as a result, the rotation of the medical instrument stops. On the other hand, when the outer tube is rotated in the second rotation direction, the tip portion of the protrusion is pressed against the inner wall surface constituting the recess and elastically deforms toward the outer tube, making it difficult to remove from the recess. As a result, even if the operating torque exceeds the threshold, the engagement state is maintained, and the medical instrument continues to rotate. In this way, with this torque transmission device, with a relatively simple configuration, it is possible to maintain the torque limiter function in one rotation direction while rotating the medical instrument with a rotational torque that exceeds the torque limiter threshold in the other rotation direction.

(3) In the torque transmission device, the recess may be formed on the inner periphery of the outer cylinder, and the protrusion may be formed on the outer periphery of the columnar body. This allows the torque limiter function to be realized with a relatively simple configuration.

(4) In the torque transmission device, the first inner wall surface that is located on the second rotation direction side among the inner wall surfaces that constitute the recess is inclined so as to be located closer to the columnar body in the second rotation direction, and the second inclination angle of the second inner wall surface that is located on the first rotation direction side with respect to a reference direction from the axis of the columnar body toward the recess may be smaller than the first inclination angle of the first inner wall surface with respect to the reference direction. In this torque transmission device, the first inner wall surface that is located on the second rotation direction side is inclined so as to be located closer to the columnar body in the second rotation direction. In addition, the second inclination angle of the second inner wall surface that is located on the first rotation direction side with respect to the reference direction is smaller than the first inclination angle of the first inner wall surface with respect to the reference direction. As a result, the engagement state can be more reliably maintained even if the operating torque exceeds a threshold when the outer cylinder is rotated in the second rotation direction, compared to a configuration in which the second inclination angle is equal to or greater than the first inclination angle.

(5) In the torque transmission device, the protrusion may be detachably attached to the columnar body. In this torque transmission device, since the protrusion is detachable from the columnar body, for example, if the protrusion deteriorates, it can be replaced with a new one.

(6) In the torque transmission device, a plurality of the protrusions may be detachably provided on the columnar body. In this torque transmission device, the threshold value of the torque limiter function can be changed, for example, by changing the number of protrusions provided on the columnar body.

(7) In the torque transmission device, the recess extends in the axial direction of the columnar body, and the columnar body is provided with a plurality of the protrusions, which are aligned in the axial direction of the columnar body and engage with a common recess. In this torque transmission device, the timing of switching between an engaged state and a released state with respect to the recess for the plurality of protrusions is suppressed from being shifted compared to a configuration in which, for example, a plurality of protrusions are arranged offset from one another in the circumferential direction of the columnar body and engage with separate recesses, and the torque limiter function can be operated with precision.

(8) In the torque transmission device described above, a plurality of the recesses may be arranged in the circumferential direction of the outer cylinder on the inner peripheral side of the outer cylinder. In this torque transmission device, a plurality of recesses are arranged in the circumferential direction of the outer cylinder on the inner peripheral side of the outer cylinder. Therefore, compared to a configuration in which only one recess is formed on the inner peripheral side of the outer cylinder, when the operating torque falls below a threshold value in the released state, the engagement state between the convex portion and the recessed portion is more likely to be restored.

(9) In the torque transmission device, a mark indicating the first rotation direction may be provided on the outer periphery of the outer cylinder. In this torque transmission device, a mark indicating the first rotation direction is provided on the outer cylinder, so that the operator can easily understand the direction in which the torque limiter function operates.

(10) The torque transmission device disclosed in this specification is a torque transmission device that transmits torque to a medical instrument, and includes a columnar body that holds the medical instrument, and an outer tube that covers the outer circumference of the columnar body. When the outer tube is rotated in a first rotation direction around the axis of the outer tube, if the rotation torque applied to the outer tube is equal to or less than a threshold value, the transmission state of the rotation torque to the columnar body is maintained, and when the rotation torque applied to the outer tube exceeds the threshold value, the transmission state is released, and when the outer tube is rotated in a second rotation direction opposite to the first rotation direction, the transmission state is maintained even if the rotation torque applied to the outer tube exceeds the threshold value. As a result, according to this torque transmission device, while maintaining the torque limiter function in one rotation direction, it is possible to perform a rotation operation of the medical instrument with a rotation torque that exceeds the threshold value of the torque limiter in the other rotation direction.

FIG. 1 is a perspective view showing an outline of an external configuration of a torque transmission device according to a first embodiment; FIG. 1 is an explanatory diagram illustrating a schematic vertical cross-sectional configuration of a torque transmission device 100 according to a first embodiment. FIG. 1 is an explanatory diagram illustrating a schematic cross-sectional configuration of a torque transmission device according to a first embodiment. FIG. 4 is a perspective view showing a schematic configuration of an inner cylinder 20 and a leaf spring 50. FIG. 1 is an explanatory diagram showing a cross-sectional state of a leaf spring 50 and an engagement groove 13 of an outer cylinder 10. FIG. 11 is an explanatory diagram illustrating a schematic cross-sectional configuration of a torque transmission device 100a according to a second embodiment. FIG. 13 is an explanatory diagram illustrating a schematic cross-sectional configuration of a torque transmission device 100b according to a third embodiment. FIG. 13 is an explanatory diagram illustrating a schematic cross-sectional configuration of a torque transmission device 100c according to a fourth embodiment. FIG. 13 is an explanatory diagram illustrating a schematic cross-sectional configuration of a torque transmission device 100d according to a fifth embodiment.

A. First embodiment:
A-1. Basic configuration of the torque transmission device 100:
Fig. 1 is a perspective view that shows a schematic external configuration of the torque transmission device 100 in the first embodiment, Fig. 2 is an explanatory diagram that shows a schematic longitudinal section configuration of the torque transmission device 100, and Fig. 3 is an explanatory diagram that shows a schematic transverse section configuration of the torque transmission device 100. Fig. 2 shows a longitudinal section configuration of the tip side of the torque transmission device 100 at the position II-II in Fig. 1, and Fig. 3 shows a transverse section configuration of the torque transmission device 100 at the position III-III in Fig. 1. Here, the longitudinal section of the torque transmission device 100 refers to a section (YZ section in Fig. 1) that is parallel to the axial direction of the torque transmission device 100 (longitudinal direction, Z-axis direction in Figs. 1 and 2, hereinafter also simply referred to as "axial direction Z"), and the transverse section of the torque transmission device 100 refers to a section (XY section in Fig. 1) that is perpendicular to the axial direction Z.

The torque transmission tool 100 is, for example, a tool for holding a proximal end portion of a linear medical device 1 (see FIG. 2) to be inserted into the body and transmitting a rotational torque to the device 1. Examples of devices include a guidewire, a catheter, a dilator, and the like. Note that FIG. 2 shows the device 1 in a state in which the device 1 is generally linear and parallel to the Z-axis direction, but the device 1 has a degree of flexibility that allows it to be bent. Note that in FIG. 2, the positive Z-axis side (the lead-out side of the device 1 of the torque transmission tool 100) is the tip side (distal side), and the negative Z-axis side (the side opposite to the lead-out side of the device 1 of the torque transmission tool 100) is the base side (proximal side) operated by a technician such as a doctor. The device 1 is an example of a medical tool in the scope of the claims.

As shown in FIG. 1, the torque transmission device 100 is, for example, a cylindrical device as a whole. As shown in FIG. 2 and FIG. 3, the torque transmission device 100 includes an outer tube 10, an inner tube 20, and a leaf spring 50.

<Outer cylinder 10>
The outer cylinder 10 is a part that is held by the operator and rotated. The outer cylinder 10 is a tubular (e.g., cylindrical) member with an opening at the tip and base ends. In this specification, the term "tubular (cylindrical)" does not necessarily mean a completely tubular shape (cylindrical shape), but may mean a substantially tubular shape as a whole (such as a slightly conical shape or a shape with some unevenness).

Inside the outer tube 10, a through hole 12 through which the inner tube 20 is inserted is formed penetrating in the axial direction Z. The through hole 12 includes a pair of end through holes 12A, 12A and a central through hole 12B. One end through hole 12A is located at the tip side of the outer tube 10, and the other end through hole 12A (omitted in FIG. 2) is located at the rear end side of the outer tube 10. The central through hole 12B is located between the pair of end through holes 12A. The diameter of the central through hole 12B is smaller than the diameter of the end through hole 12A. As shown in FIG. 2, a plurality of engagement grooves 13 are formed on the inner peripheral surface constituting the central through hole 12B. The plurality of engagement grooves 13 are arranged at predetermined intervals in the circumferential direction of the outer tube 10. Each engagement groove 13 extends linearly along the axial direction Z. The engagement groove 13 is an example of a recess in the scope of the claims.

As shown in FIG. 1, a mark 16 indicating a forward rotation direction R is provided on the outer peripheral surface of the outer tube 10. The "forward rotation direction R" is a clockwise direction (rightward on the paper surface of FIG. 3) as viewed from the base end side of the torque transmission tool 100, and the "reverse rotation direction L" is a counterclockwise direction (leftward on the paper surface of FIG. 3) as viewed from the base end side of the torque transmission tool 100. A knurl 14 is formed on the outer peripheral surface of the outer tube 10. The knurl 14 is processed to have an uneven shape and functions as a slip prevention when the operator grasps it. In FIG. 1, as an example of the knurl 14, a plurality of grooves are formed along the axial direction Z so as to be aligned in the circumferential direction of the outer tube 10. The mark 16 is provided on the tip side of the knurl 14 and in an area where the knurl 14 is not formed. This makes it easy for the operator who grasps the knurl 14 to visually recognize the mark 16 located near his/her hand, and can easily recognize the forward rotation direction R (i.e., the rotation direction in which the torque limiter function works). The forward rotation direction R is an example of a first rotation direction in the claims, and the reverse rotation direction L is an example of a second rotation direction in the claims.

<Inner cylinder 20>
The inner cylinder 20 is a part that holds the device 1 (see FIG. 2). The inner cylinder 20 is inserted into the insertion hole 12 of the outer cylinder 10, and rotates by transmitting a rotation torque (hereinafter referred to as "operation torque") applied to the outer cylinder 10 by a rotation operation by an operator. Specifically, the shape of the inner cylinder 20 is a tube (e.g., a cylindrical shape) with an opening at the tip and base end. The outer diameter of the inner cylinder 20 is smaller than the inner diameter of the outer cylinder 10. The inner cylinder 20 is accommodated in the insertion hole 12 of the outer cylinder 10 and is arranged so as to be positioned coaxially with the outer cylinder 10. An insertion hole 22 into which the device 1 is inserted is formed inside the inner cylinder 20. The inner cylinder 20 is an example of a columnar body in the claims.

As shown in FIG. 2, the inner tube 20 includes an inner tube body 21 and a pair of holding portions 30. Each holding portion 30 is housed in each end insertion hole 12A of the outer tube 10, and the inner tube body 21 is housed in the central insertion hole 12B of the outer tube 10. In this way, the outer tube 10 covers the outer circumference of the inner tube 20 over the entire length in the axial direction Z. This prevents the operator from touching the inner tube 20 and adversely affecting the rotational movement of the inner tube 20.

The holding portion 30 is a portion that holds the device 1. One holding portion 30 is located at the tip side of the inner tube 20, and the other holding portion 30 (omitted in FIG. 2) is located at the base end side of the inner tube 20. Each holding portion 30 includes a reduced diameter portion 32 and a cap 34.

Figure 4 is a perspective view showing the configuration of the inner tube 20 and the leaf spring 50. However, in Figure 4, the inner tube 20 is shown in a state in which the cap 34 described below has been removed. In addition, in Figure 4, the bearing 40 described below is also shown. As shown in Figures 2 and 4, a screw groove 33A is formed on the outer circumferential surface on the tip side of the reduced diameter portion 32. In the reduced diameter portion 32, a pair of displacement portions 33B is provided on the base end side of the screw groove 33A. The pair of displacement portions 33B are arranged so as to face each other through the insertion hole 22 (the central axis O of the torque transmission device 100). Each displacement portion 33B has a protrusion 33C, and when the displacement portion 33B is in a natural state before the cap 34 is attached to the reduced diameter portion 32, the protrusion 33C protrudes outward in the radial direction (hereinafter also simply referred to as the "radial direction") of the torque transmission device 100 from the screw groove 33A. When an external force acting radially inward is applied to the protrusion 33C, the displacement portion 33B is displaced so as to advance into the insertion hole 22.

As shown in FIG. 2, the cap 34 is a tubular (e.g., cylindrical) member with openings at the tip and base ends. The above-mentioned insertion hole 22 is formed inside the tip end side of the cap 34, and a storage hole 36 that stores the reduced diameter portion 32 is formed inside the base end side of the cap 34. The storage hole 36 communicates with the insertion hole 22 formed in the cap 34 and opens at the base end of the cap 34. The diameter of the storage hole 36 is larger than the diameter of the insertion hole 22. A screw groove 35A that screws into the screw groove 33A of the reduced diameter portion 32 is formed on the tip side of the inner circumferential surface of the cap 34 that constitutes the storage hole 36.

With the base end portion of the device 1 inserted into the reduced diameter portion 32 of the holding portion 30, the thread grooves 35A of each cap 34 are screwed into the thread grooves 33A of the reduced diameter portion 32 using a jig (not shown). Then, the protrusions 33C of each displacement portion 33B of the reduced diameter portion 32 are pressed radially inward by the inner circumferential surface of the cap 34, and each displacement portion 33B is displaced so as to advance into the insertion hole 22. As a result, the device 1 is sandwiched between the pair of displacement portions 33B. In other words, the device 1 is held by the holding portion 30.

The inner cylinder body 21 is located between the pair of holding portions 30 in the axial direction Z. In this embodiment, the inner cylinder body 21 and the pair of reduced diameter portions 32 are integrally formed. The inner cylinder body 21 is, for example, cylindrical.

3 and 4, a plurality of support parts 25 for supporting the leaf spring 50 are formed on the outer circumferential surface of the inner tube body 21. Each support part 25 is a recess extending linearly along the axial direction Z, into which a base part 54 of the leaf spring 50 described later can be inserted. In this embodiment, the plurality of support parts 25 includes a first group of support parts 25 and a second group of support parts 25. The first group of support parts 25 is composed of a plurality of support parts 25 (four in FIG. 4) arranged at a predetermined interval in the axial direction Z. The second group of support parts 25 is located at a different position from the first group of support parts 25 in the circumferential direction of the inner tube 20, and is composed of a plurality of support parts 25 (four in FIG. 4) arranged at a predetermined interval in the axial direction Z. The first group of support parts 25 and the second group of support parts 25 are located at the same position in the axial direction Z. In addition, when viewed from the axial direction Z, the shape of the support parts 25 of the first group and the shape of the support parts 25 of the second group are point symmetrical about the central axis O of the inner cylinder 20 (see FIG. 3).

As shown in Figs. 2 to 4, a bearing 40 is disposed between the outer tube 10 and the inner tube 20. Specifically, the bearing 40 is a ball bearing that is fitted into each of a pair of reduced diameter portions 32 in the inner tube 20, and the outer peripheral surface of this ball bearing is in contact with the inner peripheral surface of the outer tube 10. This makes it possible to prevent a decrease in torque transmission efficiency from the outer tube 10 to the inner tube 20 or a malfunction of the torque limiter function due to contact resistance between the outer tube 10 and the inner tube 20.

The outer tube 10 and the inner tube 20 may each be made of a resin material (e.g., polyethylene terephthalate, polyacetal, polyether ether ketone, polypropylene) or a metal material (e.g., stainless steel, aluminum alloy, titanium alloy, magnesium alloy). The outer tube 10 and the inner tube 20 may each be made of the same material, or may each be made of different materials.

<Leaf spring 50>
As shown in Fig. 4, the leaf spring 50 is a flat member as a whole. The leaf spring 50 includes a protruding portion 52 and a base portion 54. In Fig. 4, the base portion 54 is shown by a virtual line. The planar shape of the protruding portion 52 is substantially rectangular. The base portion 54 is located on one end side of the protruding portion 52, and both ends of the base portion 54 protrude outward from the protruding portion 52 in the axial direction Z.

The base portion 54 of the leaf spring 50 has a shape that allows it to be inserted into the support portion 25 of the inner tube 20, thereby allowing the leaf spring 50 to be detachably attached to the inner tube 20. Specifically, the base portion 54 is inserted into the support portion 25 in a position that is approximately parallel to the axial direction. This maintains the leaf spring 50 (protruding portion 52) in a position that is approximately parallel to the axial direction, and prevents the position of the leaf spring 50 from shifting in the axial direction Z.

The protruding portion 52 of the leaf spring 50 protrudes radially outward from the outer circumferential surface of the inner tube 20 when the base portion 54 is inserted into the support portion 25. As shown in FIG. 4, the protruding portion 52 is oriented substantially parallel to the axial direction Z. The leaf spring 50 is an example of a convex portion within the scope of the claims.

<Relationship between the engagement groove 13 of the outer cylinder 10 and the leaf spring 50>
3, the tip portion of the protruding portion 52 circumferentially engages with the engagement groove 13 of the outer cylinder 10. Specifically, the tip portion of the protruding portion 52 extending in the axial direction Z is inserted into the engagement groove 13 also extending in the axial direction Z. Furthermore, when viewed from the axial direction Z, the tip portion of the protruding portion 52 extends in a direction L2 inclined toward the positive rotation direction R with respect to a reference direction L1 extending from the central axis O of the torque transmission device 100 toward the engagement groove 13.

The inner wall surfaces constituting the engagement groove 13 are composed of a first inner wall surface 13A, a second inner wall surface 13B, and a connecting surface 13C. The first inner wall surface 13A is located on the reverse rotation direction L side, the second inner wall surface 13B is located on the forward rotation direction R side, and the connecting surface 13C is located between the first inner wall surface 13A and the second inner wall surface 13B and connects them. The first inner wall surface 13A is inclined so that it is located on the reverse rotation direction L side as it is closer to the inner cylinder 20. In addition, the second inclination angle of the second inner wall surface 13B with respect to the reference direction L1 is smaller than the first inclination angle of the first inner wall surface 13A with respect to the reference direction L1. In addition, it is preferable that the first inclination angle is 30 degrees or more, and the second inclination angle is preferably zero degrees or less. In addition, each inner wall surface 13A, 13B, 13C may be a flat surface or a curved surface. Additionally, the engagement groove 13 may be configured without having a connecting surface 13C.

The leaf springs 50 inserted into each of the multiple support parts 25 belonging to the first group are lined up along the axial direction Z, and all of them engage with a common engagement groove 13. The leaf springs 50 inserted into each of the multiple support parts 25 belonging to the second group are lined up along the axial direction Z, and all of them engage with a common engagement groove 13. Note that the engagement groove 13 with which the support parts 25 of the first group engage is different from the engagement groove 13 with which the support parts 25 of the second group engage.

The leaf spring 50 is made of an elastically deformable material, and may be made of, for example, a metal material (e.g., stainless steel, nickel titanium) or a resin material (e.g., polyethylene terephthalate, polypropylene, polyethylene).

A-2. Advantages of this embodiment:
5 is an explanatory diagram showing the state of the leaf spring 50 and the engagement groove 13 of the outer cylinder 10 in a cross section. As described above, in the torque transmission device 100 of this embodiment, the protruding portion 52 of the leaf spring 50 extends in a direction inclined toward the positive rotation direction R with respect to the reference direction L1 from the central axis O toward the engagement groove 13 (see FIG. 3). Therefore, when the outer cylinder 10 is rotated in the positive rotation direction R, if the operating torque is equal to or less than a threshold value, the engagement state between the leaf spring 50 and the engagement groove 13 is maintained, and the inner cylinder 20 rotates in conjunction with the rotation of the outer cylinder 10, and as a result, the device 1 rotates.

When the outer cylinder 10 is rotated in the forward rotation direction R, if the operating torque exceeds a threshold value, as shown in FIG. 5(A), the protruding portion 52 of the leaf spring 50 is pressed against the inner wall surface (first inner wall surface 13A) of the engagement groove 13 and elastically deforms toward the inner cylinder 20, and is removed from the engagement groove 13, releasing the above-mentioned engagement state, and the outer cylinder 10 spins freely relative to the inner cylinder 20. In other words, the torque limiter function is activated, and as a result, the torque of the outer cylinder 10 is not transmitted to the device 1, and the rotation of the device 1 stops. Therefore, when the outer cylinder 10 is rotated in the forward rotation direction R, it is possible to prevent excessive operating torque from being transmitted to the device 1.

On the other hand, as shown in FIG. 5(B), when the outer tube 10 is rotated in the reverse rotation direction L, the protruding portion 52 of the leaf spring 50 is pressed by the inner wall surfaces (second inner wall surface 13B, connecting surface 13C) that constitute the engagement groove 13 and elastically deforms toward the outer tube, making it difficult to remove from the engagement groove 13. As a result, whether the operating torque is below the threshold value or exceeds the threshold value, the engagement state is maintained and the transmission of rotational torque from the outer tube 10 to the inner tube 20 continues. Therefore, the rotation of the device 1 continues. Therefore, for example, if the device 1 gets caught in a predetermined place inside the body, the outer tube can be rotated in the reverse rotation direction L with an operating torque greater than the threshold value to rotate the device 1, and the device 1 can be removed from the predetermined place.

In this way, according to this embodiment, with a relatively simple configuration using the leaf spring 50, it is possible to perform rotational operation of the device 1 with a rotational torque that exceeds the threshold value of the torque limiter function in the reverse rotation direction L while maintaining the torque limiter function in the forward rotation direction R.

In this embodiment, the first inner wall surface 13A is inclined so that the closer it is to the inner cylinder 20, the more it is positioned in the reverse rotation direction L (see FIG. 3). In addition, the second inclination angle of the second inner wall surface 13B with respect to the reference direction L1 is smaller than the first inclination angle of the first inner wall surface 13A with respect to the reference direction L1. As a result, when the outer cylinder 10 is rotated in the reverse rotation direction L, the engaged state can be more reliably maintained even if the operating torque exceeds a threshold value, compared to a configuration in which, for example, the second inclination angle is equal to or greater than the first inclination angle.

In this embodiment, the leaf spring 50 is detachably attached to the inner tube 20 (see FIG. 4). Therefore, for example, if the leaf spring 50 deteriorates, it can be replaced with a new one. Also, the leaf spring 50 can be formed from a material different from that of the inner tube 20 (for example, a material having a higher breaking strength than the material from which the inner tube 20 is formed). Also, multiple leaf springs 50 are detachably attached to the inner tube 20. As a result, for example, by changing the number of leaf springs 50 provided on the inner tube 20, the threshold value of the torque limiter function can be changed.

In this embodiment, the leaf springs 50 adjacent to each other in the axial direction Z (the leaf springs 50 supported by the support portions 25 of each group (first group, second group)) are aligned in the axial direction Z and engage with a common engagement groove 13 (see Figures 3 and 4). As a result, compared to a configuration in which the leaf springs 50 adjacent to each other in the axial direction Z are offset from each other in the circumferential direction of the inner tube 20 and engage with separate engagement grooves 13, the timing of switching between the engagement state and the release state with the engagement groove 13 for the leaf springs 50 is suppressed from being off, and the torque limiter function can be operated with precision.

In this embodiment, multiple engagement grooves 13 are arranged in the circumferential direction of the outer tube 10 on the inner circumferential side of the outer tube 10 (see FIG. 3). Therefore, compared to a configuration in which only one engagement groove 13 is formed on the inner circumferential side of the outer tube 10, when the operating torque falls below a threshold value in the released state, the leaf spring 50 and the engagement groove 13 are more likely to return to their engaged state.

In this embodiment, the torque limiter function is activated when the outer tube 10 is rotated in the forward rotation direction R (see FIG. 5), making it easier for a right-handed operator to rotate his/her arm outward, making operation easier. In addition, the outer tube 10 is provided with a mark 16 indicating the forward rotation direction R (see FIG. 1), allowing the operator to easily understand the direction in which the torque limiter function is activated.

B. Second embodiment:
6 is an explanatory diagram showing a schematic cross-sectional configuration of a torque transmission device 100a according to the second embodiment. In the following, the configuration of the torque transmission device 100a according to the second embodiment that is the same as that of the torque transmission device 100 according to the first embodiment described above is denoted by the same reference numerals and description thereof will be omitted as appropriate.

As shown in FIG. 6, in the torque transmission device 100a of the second embodiment, a plurality of engagement grooves 13a extending in the axial direction are formed on the inner peripheral surface of the outer tube 10a. The inner wall surface constituting each engagement groove 13a is composed of a first inner wall surface 13aA located on the reverse rotation direction L side and a second inner wall surface 13aB located on the forward rotation direction R side. The first inner wall surface 13aA is inclined so as to be located on the reverse rotation direction L side as it is closer to the inner tube 20a. In addition, the second inclination angle of the second inner wall surface 13aB with respect to the reference direction L1 is smaller than the first inclination angle of the first inner wall surface 13aA with respect to the reference direction L1. Note that the first inclination angle is preferably 30 degrees or more, and the second inclination angle is preferably zero degrees or less. The engagement groove 13a is an example of a recess in the claims.

A plurality of support parts 25a are formed on the outer peripheral surface of the inner tube 20a. Each support part 25a is a recess extending linearly along the axial direction Z, into which the engagement mechanism 50a can be inserted. The engagement mechanism 50a includes a displacement part 52a and a spring part 54a. The displacement part 52a protrudes radially outward from within the support part 25a, and its tip part engages with the engagement groove 13a in the circumferential direction. The spring part 54a is disposed between the displacement part 52a and the bottom surface of the support part 25a, and elastically deforms in response to the displacement of the displacement part 52a. In this embodiment, the displacement part 52a has a shape extending in the reference direction L1, and is displaceable along the reference direction L1. When the displacement part 52a is subjected to a radially inward pressing force, the spring part 54a elastically deforms. The displacement part 52a is an example of a convex part in the claims.

According to the above configuration, when the outer cylinder 10a is rotated in the forward rotation direction R, if the operation torque is equal to or less than the threshold value, the engagement state between the displacement portion 52a of the engagement mechanism 50a and the engagement groove 13a is maintained, and the inner cylinder 20a rotates in conjunction with the rotation of the outer cylinder 10a, and as a result, the device 1 rotates. When the outer cylinder 10a is rotated in the forward rotation direction R, if the operation torque exceeds the threshold value, the displacement portion 52a is pressed against the inner wall surface (first inner wall surface 13aA) of the engagement groove 13a, and is guided by the inclination of the first inner wall surface 13aA to retreat into the support portion 25a, and the above-mentioned engagement state is released by coming out of the engagement groove 13a, and the outer cylinder 10a rotates freely relative to the inner cylinder 20a. That is, the torque limiter function works, and as a result, the rotation of the device 1 stops. Therefore, when the outer cylinder 10a is rotated in the forward rotation direction R, it is possible to suppress the transmission of excessive operation torque to the device 1.

On the other hand, when the outer tube 10a is rotated in the reverse rotation direction L, the displacement portion 52a receives only a circumferential force from the inner wall surface (second inner wall surface 13aB) that constitutes the engagement groove 13a, so it does not displace in the radial direction and is difficult to remove from the engagement groove 13a. As a result, whether the operating torque is below the threshold value or exceeds the threshold value, the engagement state is maintained and the transmission of rotational torque from the outer tube 10a to the inner tube 20a continues. Therefore, the rotation of the device 1 continues. Therefore, for example, if the device 1 gets caught in a predetermined location inside the body, the outer tube can be rotated in the reverse rotation direction L with an operating torque greater than the threshold value to rotate the device 1, thereby allowing the device 1 to be removed from the predetermined location.

C. Third embodiment:
7 is an explanatory diagram showing a schematic cross-sectional configuration of a torque transmission device 100b according to the third embodiment. In the following, the configuration of the torque transmission device 100b according to the third embodiment that is the same as that of the torque transmission device 100 according to the first embodiment described above is denoted by the same reference numerals and the description thereof will be omitted as appropriate.

In the first embodiment, the leaf spring 50 is exemplified as a convex portion having a substantially linear shape when viewed from the axial direction Z. In contrast, as shown in FIG. 7, in the torque transmission device 100b of the third embodiment, the leaf spring 50b has a broken line shape when viewed from the axial direction Z. Specifically, the leaf spring 50b includes a tip portion 52b and a base portion 54b. The base portion 54b is linear and extends along the reference direction L1, and the base end side is embedded in the inner tube 20b. The tip portion 52b extends from the tip of the base portion 54b in a direction L2 inclined with respect to the reference direction L1, and engages with the engagement groove 13. The leaf spring 50b may be configured to be detachably provided on the inner tube 20b. The leaf spring 50b is an example of a convex portion in the claims.

According to the above configuration, when the outer cylinder 10 is rotated in the forward rotation direction R, if the operating torque is equal to or less than the threshold value, the engagement state between the tip portion 52b of the leaf spring 50b and the engagement groove 13 is maintained, and the inner cylinder 20b rotates in conjunction with the rotation of the outer cylinder 10, resulting in the rotation of the device 1. When the outer cylinder 10 is rotated in the forward rotation direction R, if the operating torque exceeds the threshold value, the tip portion 52b is pressed against the inner wall surface of the engagement groove 13 and elastically deforms toward the inner cylinder 20b, and the engagement state is released by coming out of the engagement groove 13, and the outer cylinder 10 rotates freely relative to the inner cylinder 20b. In other words, the torque limiter function is activated, and as a result, the rotation of the device 1 is stopped. Therefore, when the outer cylinder 10 is rotated in the forward rotation direction R, it is possible to suppress the transmission of excessive operating torque to the device 1.

On the other hand, when the outer tube 10 is rotated in the reverse rotation direction L, the tip portion 52b of the leaf spring 50b is pressed against the inner wall surface that constitutes the engagement groove 13 and elastically deforms toward the outer tube, making it difficult to remove from the engagement groove 13. As a result, whether the operating torque is below the threshold value or exceeds the threshold value, the engaged state is maintained and the transmission of rotational torque from the outer tube 10 to the inner tube 20b continues. This allows the device 1 to continue rotating. Therefore, for example, if the device 1 gets caught in a predetermined location inside the body, the device 1 can be removed from the predetermined location by rotating the outer tube in the reverse rotation direction L with an operating torque greater than the threshold value to rotate the device 1.

D. Fourth embodiment:
8 is an explanatory diagram showing a schematic cross-sectional configuration of a torque transmission device 100c according to the fourth embodiment. In the following, the configuration of the torque transmission device 100c according to the fourth embodiment that is the same as that of the torque transmission device 100 according to the first embodiment described above is denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

In the first embodiment, the protrusion is exemplified by a plate-shaped leaf spring 50 having a substantially uniform thickness overall. In contrast, as shown in FIG. 8, in the torque transmission device 100c of the fourth embodiment, the engagement mechanism 50c is structured such that the rigidity when receiving a force in the reverse rotation direction L is greater than the rigidity when receiving a force in the forward rotation direction R. That is, the engagement mechanism 50c is less likely to bend in the reverse rotation direction L than in the forward rotation direction R. Specifically, the engagement mechanism 50c includes a leaf spring 52c and a reinforcing plate 54c. The leaf spring 52c is linear and extends along the reference direction L1, the base end side is embedded in the inner tube 20c, and the tip portion engages with the engagement groove 13 in the circumferential direction. The reinforcing plate 54c is linear and extends along the reference direction L1, the base end side is embedded in the inner tube 20c, and the tip portion protrudes toward the outer tube 10 while being located inside the inner circumferential surface of the outer tube 10, and does not engage with the engagement groove 13. The reinforcing plate 54c is positioned on the reverse rotation direction L side of the leaf spring 52c and is positioned adjacent to the leaf spring 52c.

According to the above configuration, when the outer tube 10 is rotated in the forward rotation direction R, if the operating torque is equal to or less than the threshold value, the leaf spring 52c of the engagement mechanism 50c is maintained in engagement with the engagement groove 13, and the inner tube 20c rotates in conjunction with the rotation of the outer tube 10, resulting in the rotation of the device 1. When the outer tube 10 is rotated in the forward rotation direction R, if the operating torque exceeds the threshold value, the leaf spring 52c is pressed against the inner wall surface of the engagement groove 13 and elastically deforms toward the inner tube 20c, and is released from the engagement groove 13, releasing the above-mentioned engagement state, and the outer tube 10 rotates freely relative to the inner tube 20c. In other words, the torque limiter function is activated, and as a result, the rotation of the device 1 is stopped. Therefore, when the outer tube 10 is rotated in the forward rotation direction R, it is possible to suppress the transmission of excessive operating torque to the device 1.

On the other hand, when the outer tube 10 is rotated in the reverse rotation direction L, the leaf spring 52c of the engagement mechanism 50c is pressed against the inner wall surface that constitutes the engagement groove 13, but due to the presence of the reinforcing plate 54c, it is difficult to deform and difficult to come out of the engagement groove 13. As a result, whether the operating torque is below the threshold value or exceeds the threshold value, the engagement state is maintained and the transmission of rotational torque from the outer tube 10 to the inner tube 20c continues. Therefore, the rotation of the device 1 continues. Therefore, for example, if the device 1 gets caught in a predetermined place inside the body, the device 1 can be removed from the predetermined place by rotating the outer tube in the reverse rotation direction L with an operating torque greater than the threshold value to rotate the device 1.

E. Fifth embodiment:
9 is an explanatory diagram showing a schematic cross-sectional configuration of a torque transmission device 100d according to the fifth embodiment. In the following, the configuration of the torque transmission device 100d according to the fifth embodiment that is the same as that of the torque transmission device 100 according to the first embodiment described above is denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

In the first embodiment, a recess (engagement groove 13) was formed in the outer tube 10 and a protrusion was formed in the columnar body (inner tube 20). In the fifth embodiment, a protrusion (leaf spring 50d) is formed in the outer tube 10d, and a recess (engagement groove 13d) is formed in the columnar body (inner tube 20d).

Specifically, as shown in FIG. 9, the tip portion of the leaf spring 50d circumferentially engages with the engagement groove 13d of the inner cylinder 20d. When viewed from the axial direction Z, the tip portion of the leaf spring 50d extends in a direction L2d that is inclined toward the positive rotation direction R with respect to a reference direction L1d that runs from the central axis O of the torque transmission device 100d toward the engagement groove 13d.

The inner wall surface constituting the engagement groove 13d is composed of a first inner wall surface 13dA, a second inner wall surface 13dB, and a connecting surface 13dC. The first inner wall surface 13dA is located on the reverse rotation direction L side, the second inner wall surface 13dB is located on the forward rotation direction R side, and the connecting surface 13dC is located between the first inner wall surface 13dA and the second inner wall surface 13dB and connects them. The second inner wall surface 13dB is inclined so that it is located closer to the outer tube 10d in the forward rotation direction R side. In addition, the third inclination angle of the first inner wall surface 13dA with respect to the reference direction L1d is smaller than the fourth inclination angle of the second inner wall surface 13dB with respect to the reference direction L1d. In addition, it is preferable that the third inclination angle is 30 degrees or more, and the fourth inclination angle is preferably zero degrees or less. In addition, each of the inner wall surfaces 13dA, 13dB, and 13dC may be a flat surface or a curved surface. Furthermore, the engagement groove 13d may not have a coupling surface 13dC.

According to the fifth embodiment, a relatively simple configuration using a leaf spring 50d allows the device 1 to be rotated with a rotational torque that exceeds the threshold of the torque limiter function in the reverse rotation direction L while maintaining the torque limiter function in the forward rotation direction R.

In the fifth embodiment, the second inner wall surface 13dB is inclined so that the closer it is to the outer cylinder 10d, the more it is positioned in the forward rotation direction R (see FIG. 9). In addition, the third inclination angle of the first inner wall surface 13dA relative to the reference direction L1d is smaller than the fourth inclination angle of the second inner wall surface 13dB relative to the reference direction L1d. As a result, when the outer cylinder 10d is rotated in the reverse rotation direction L, the engaged state can be more reliably maintained even if the operating torque exceeds the threshold value, compared to a configuration in which the third inclination angle is equal to or greater than the fourth inclination angle.

F. Variations:
The technology disclosed in this specification is not limited to the above-described embodiments, and can be modified in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

The configurations of the torque transmission devices 100, 100a, 100b, and 100c in the above embodiments are merely examples and can be modified in various ways. For example, in the above embodiments, the cross-sectional shape of the outer tube 10 is not limited to a circle, and may be, for example, a polygon. In the above embodiments, the number of engagement grooves 13, 13a formed on the inner peripheral surface of the outer tube 10, 10a may be one. In the above embodiments, the engagement grooves 13, 13a are exemplified as examples of recesses, but the recesses may not extend in the axial direction Z. In short, it is sufficient that the recesses can engage with the protrusions provided on the inner tube. In the first, third, and fourth embodiments, the second inclination angle of the second inner wall surface 13B with respect to the reference direction L1 may be equal to or greater than the first inclination angle of the first inner wall surface 13A with respect to the reference direction L1.

In the above embodiment, the holding portion 30 that clamps and holds the device 1 is exemplified as a configuration in which the columnar body holds the medical instrument, but the device 1 may be held by other holding structures, such as a configuration in which the device 1 is locked and held. The columnar body is not limited to being cylindrical, and may be a solid column. In short, the columnar body may be configured to be capable of holding a medical instrument. The medical instrument is not limited to being a linear device, and may be, for example, one that has a three-dimensional structure (a surgical instrument such as a basket-type grasping forceps).

In the first and second embodiments described above, only one support portion 25, 25a may be formed on the outer peripheral surface of the inner tube 20, 20a. In the first embodiment described above, when viewed from the axial direction Z, multiple protrusions (a pair of leaf springs 50 in FIG. 3) are arranged point-symmetrically around the central axis O of the inner tube 20, but multiple protrusions may be arranged asymmetrically or only one protrusion may be arranged.

In the above embodiment, multiple protrusions (such as leaf springs 50) are arranged in the axial direction Z, but multiple protrusions may be arranged at different positions in the circumferential direction. Also, in the first embodiment, multiple leaf springs 50 may be arranged offset from each other in the circumferential direction of the inner tube 20 and engage with different engagement grooves 13.

In the above embodiment, leaf springs 50, 50b, and 52c are given as examples of elastic protrusions, but they may also be elastic rod-shaped bodies, etc.

In the above embodiment, the outer cylinders 10, 10a may be configured to cover a portion of the inner cylinders 20 to 20c.

In the first, third and fourth embodiments, the leaf spring 50 may be fixed to the inner cylinder 20 in an undetachable manner. Also, the configuration may include only one leaf spring 50.

In each of the above embodiments, the torque limiter function is realized by engagement between the concave and convex portions in the rotational direction. However, by a configuration other than the engagement, the configuration may be such that "when the outer cylinder is rotated in a first rotational direction, if the rotational torque applied to the outer cylinder is equal to or less than a threshold value, the transmission state of the rotational torque to the columnar body is maintained, and when the rotational torque applied to the outer cylinder exceeds the threshold value, the transmission state is released, and when the outer cylinder is rotated in a second rotational direction, the transmission state is maintained even if the rotational torque applied to the outer cylinder exceeds the threshold value." For example, the following example may be given.
(a) A coil wound around the outer periphery of a columnar body is placed between the columnar body and an outer cylinder, one end of the coil is fixed to the columnar body and the other end is fixed to the outer cylinder, and the looseness and tightness of the coil are utilized.
(b) A form in which the coefficient of friction between the outer cylinder and the columnar body when the outer cylinder is rotated in a first rotation direction is smaller than the coefficient of friction between the outer cylinder and the columnar body when the outer cylinder is rotated in a second rotation direction.
(c) An orifice mechanism is provided between the columnar body and the outer cylinder, and the opening and closing of the orifice mechanism is utilized.
(d) A form in which a braid is disposed between the columnar body and the outer tube, and the twisting direction of the braid is utilized.

The materials used for each component in the above embodiment are merely examples and can be modified in various ways.

1: Device 10, 10a, 10d: Outer tube 12: Insertion hole 12A: End insertion hole 12B: Central insertion hole 13, 13a, 13d: Engagement groove 13A, 13aA, 13dA: First inner wall surface 13B, 13aB, 13dB: Second inner wall surface 13C, 13dC: Connection surface 14: Knurling 16: Mark 20-20d: Inner tube 21: Inner tube main body 22: Insertion hole 25, 25a: Support portion 30: Holding portion 32: Reduced diameter portion 33A: Thread groove 33B: Displacement portion 33C: Protrusion 34: Cap 35A: Thread groove 36: Accommodation hole 40: Bearing 50, 50b, 52c, 50d: Leaf spring 50a, 50c: Engagement mechanism 52: Protruding part 52a: Displacement part 52b: Tip part 54, 54b: Base part 54a: Spring part 54c: Reinforcement plate 100, 100a, 100b, 100c: Torque transmission device L1: Reference direction L2: Inclined direction L: Reverse rotation direction O: Central axis R: Forward rotation direction Z: Axial direction

Claims (11)

A torque transmission device for transmitting torque to a medical instrument,
A columnar body for holding the medical instrument;
An outer cylinder covering the outer periphery of the columnar body;
Equipped with
a recess is formed in a first member, which is one of the columnar body and the outer cylinder, and a protrusion that engages with the recess is formed in a second member, which is the other of the columnar body and the outer cylinder;
The recess and the protrusion are
a first angle at which an abutment surface between the recess and the protrusion is inclined with respect to a first reference direction from an axis of the columnar body toward the recess when the columnar body is rotated in the first rotation direction is larger than a second angle at which an abutment surface between the recess and the protrusion is inclined with respect to the first reference direction when the columnar body is rotated in the second rotation direction,
When the outer cylinder is rotated in a first rotation direction around the axis of the outer cylinder, if a rotational torque applied to the outer cylinder is equal to or less than a threshold value, an engagement state between the convex portion and the concave portion is maintained, and if the rotational torque applied to the outer cylinder exceeds the threshold value, the engagement state is released;
When the outer cylinder is rotated in a second rotation direction opposite to the first rotation direction, even if a rotational torque applied to the outer cylinder exceeds the threshold value, the engagement state is maintained.
Torque transmission device. The torque transmission device according to claim 1 ,
The protrusion has elasticity,
In a cross section of the outer cylinder, a tip portion of the protrusion extends in a direction inclined toward the first rotation direction with respect to a reference direction from an axis of the columnar body toward the recess.
Torque transmission device. The torque transmission device according to claim 1 ,
The recess is formed on the inner peripheral side of the outer cylinder,
The protrusion is formed on the outer circumferential side of the columnar body.
Torque transmission device. The torque transmission device according to claim 3 ,
Among inner wall surfaces constituting the recess, a first inner wall surface located on the second rotation direction side is inclined so as to be located closer to the columnar body toward the second rotation direction side,
a second inclination angle of the second inner wall surface located on the first rotation direction side with respect to a reference direction from the axis of the columnar body toward the recess is smaller than a first inclination angle of the first inner wall surface with respect to the reference direction;
Torque transmission device. The torque transmission device according to claim 1 ,
The protrusion is formed on the inner peripheral side of the outer cylinder,
The recess is formed on the outer circumferential side of the columnar body.
Torque transmission device. The torque transmission device according to claim 5 ,
Among the inner wall surfaces constituting the recess, a first inner wall surface located on the second rotation direction side is inclined so as to be positioned closer to the outer cylinder in the second rotation direction,
a second inclination angle of the second inner wall surface located on the first rotation direction side with respect to a reference direction from the axis of the columnar body toward the recess is larger than a first inclination angle of the first inner wall surface with respect to the reference direction;
Torque transmission device. A torque transmission device according to any one of claims 1 to 6 ,
The second member is detachably provided on the columnar body.
Torque transmission device. A torque transmission device according to claim 7 ,
A plurality of the protrusions are detachably provided on the second member.
Torque transmission device. A torque transmission device according to any one of claims 1 to 8 ,
The recess extends in an axial direction of the columnar body,
The second member is provided with a plurality of the protrusions,
The plurality of protrusions are aligned in the axial direction of the columnar body and engage with a common recess.
Torque transmission device. A torque transmission device according to any one of claims 1 to 9 ,
The first member has a plurality of recesses arranged in a circumferential direction of the outer cylinder.
Torque transmission device. A torque transmission device according to any one of claims 1 to 10 ,
A mark indicating the first rotation direction is provided on the outer periphery of the outer cylinder.
Torque transmission device.

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