Jaw assembly and grip surface structure thereof

Abstract

To provide a jaw assembly capable of reliably gripping a flexible wire rod between grip surfaces even without increasing a sandwiching force.SOLUTION: A jaw assembly 1 includes: a plurality of projection parts 9 and 11 projecting so as to be able to mesh with grip surfaces 3a and 5a of a set of jaws 3 and 5 and being discontinuous in a direction of traversing the grip surfaces 3a and 5a; a plurality of trough parts 16 formed between the projection parts 9 and 11 adjacent in a crossing direction with respect to the traversing direction; and a plurality of recessed parts 13 formed between the trough parts 16 adjacent in the traversing direction and facing the trough parts 16.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a jaw assembly for use in a robot, a manipulator, or the like, and to a gripping surface structure thereof. [Background technology]

[0002] An example of a conventional jaw assembly is a surgical instrument described in Patent Document 1. This surgical instrument has a pair of jaws that can be opened and closed. The jaws have gripping surfaces that grip each other when closed. The gripping surfaces have a plurality of interlocking projections. On each gripping surface, linear grooves are formed between adjacent projections in a direction that crosses the gripping surface.

[0003] In such a surgical instrument, a flexible wire such as a suture can be clamped between the bottom of a groove on the gripping surface of one jaw and the top of a convex portion on the gripping surface of the other jaw, allowing the wire to be gripped by the pair of jaws.

[0004] However, when a wire is clamped between the bottom of the linear groove and the top of the protrusion, the clamping force on the wire depends solely on the clamping force between the clamping surfaces, which can cause the clamped wire to slip along the groove and the protrusion.

[0005] In order to prevent the wire from slipping, the clamping force between the clamping surfaces should be increased, but it may be difficult to increase the clamping force.

[0006] Such problems are common when gripping flexible wires in various devices. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2019-518580 Summary of the Invention [Problem to be solved by the invention]

[0008] The problem to be solved is that there is a limit to how much flexible wire can be gripped without increasing the clamping force between the gripping surfaces. [Means for solving the problem]

[0009] The present invention provides a jaw assembly comprising a set of jaws having gripping surfaces capable of gripping a wire when closed, a plurality of protrusions that protrude from the gripping surfaces of the set of jaws and are discontinuous in a direction transverse to the gripping surfaces so as to be able to intermesh with each other, a plurality of valleys formed between adjacent protrusions in a direction intersecting the transverse direction, and a plurality of recesses formed between adjacent valleys in the transverse direction and corresponding to the valleys.

[0010] The present invention also provides a gripping surface structure applicable to a set of jaws that grip a wire rod in a closed state, the gripping surface structure comprising: a gripping surface for gripping the wire rod; a plurality of convex portions protruding from the gripping surface and discontinuous in a direction transverse to the gripping surface; a plurality of valley portions formed between adjacent convex portions of the plurality of convex portions; and a plurality of recesses formed between adjacent valley portions of the plurality of valley portions relative to the valley portions. [Effects of the Invention]

[0011] The present invention makes it possible to more reliably grip a flexible wire between gripping surfaces without increasing the clamping force. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view of a jaw according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged perspective view of a portion of the jaw of FIG. [Figure 3] FIG. 3 is a side view of a portion of a jaw assembly using the jaw of FIG. [Figure 4] 4 is a perspective cross-sectional view taken along line IV-IV in FIG. [Figure 5]FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] 6 is a side perspective view of a portion of the jaw assembly of FIG. 3 in a gripping position. [Figure 7] 7 is a front view showing the relationship between the gripping surfaces of the jaws of FIG. 1 and the suture. [Figure 8] 8 is a front view showing the relationship between the gripping surfaces of the jaws of FIG. 1 and the suture. [Figure 9] FIG. 9 is a perspective view of a jaw according to a comparative example. [Figure 10] FIG. 10 is a side view showing a part of a jaw according to a comparative example. [Figure 11] FIG. 11 is an explanatory diagram showing an experiment state of the gripping force of the jaw assembly according to the embodiment. [Figure 12] 12(A) to 12(D) are explanatory views showing a part of an experimental state when sutures in different directions are gripped by different parts of the jaw assembly. [Figure 13] FIG. 13 is a chart showing experimental data on the gripping force of the jaw assemblies of FIGS. 12(A) to 12(D). DETAILED DESCRIPTION OF THE INVENTION

[0013] The objective of being able to more reliably grip a flexible wire between the gripping surfaces without increasing the clamping force is achieved by providing a recess adjacent to the valley between a plurality of discontinuous protrusions that protrude so as to be able to interlock with each other between the gripping surfaces of a pair of jaws.

[0014] The jaw assembly 1 includes a pair of jaws 3 and 5, a plurality of protrusions 9 and 11, a plurality of valleys 16, and a plurality of recesses 13. The jaws 3 and 5 have gripping surfaces 3a and 5a that can grip a wire 15 when closed. The plurality of protrusions 9 and 11 protrude from the gripping surfaces 3a and 5a of the pair of jaws 3 and 5, respectively, so as to be able to interlock with each other, and are discontinuous in a direction transverse to the gripping surfaces 3a and 5a. The plurality of valleys 16 are formed between the protrusions 9 and 11 adjacent to each other in a direction intersecting the transverse direction. The plurality of recesses 13 are formed between the valleys 16 adjacent to each other in the transverse direction, and are recessed relative to the valleys 16.

[0015] The multiple protrusions 9 and 11 each have inclined surfaces 9a and 11a that converge at the tip in the protruding direction, and the wire 15 may be clamped between the inclined surfaces 9a and 11a of the protrusions 9 and 11 that mesh with each other between a pair of jaws 3 and 5.

[0016] On both sides of the valley portion 16 in the intersecting direction, the slopes 9a and 11a of the protrusions 9 that hold the wire 15 therebetween may be inclined in opposite directions.

[0017] Each of the protrusions 9 and 11 is preferably cone-shaped, more preferably square pyramid-shaped. The sides of the square pyramid-shaped protrusions 9 and 11 preferably extend along the transverse direction. [Example]

[0018] [Jaw assembly] Fig. 1 is a perspective view of a jaw according to an embodiment of the present invention. Fig. 2 is an enlarged perspective view showing a portion of the jaw of Fig. 1. Fig. 3 is a side view showing a portion of a jaw assembly using the jaw of Fig. 1. Fig. 4 is a perspective cross-sectional view taken along line IV-IV of Fig. 3. Fig. 5 is a cross-sectional view taken along line VV of Fig. 3.

[0019] The jaw assembly 1 is applicable to robots, manipulators, and other devices in various fields such as medicine and industry. In this embodiment, the jaw assembly 1 is a forceps used in a surgical support robot, a surgical support manipulator, or the like.

[0020] This jaw assembly 1 is supported on a shaft 17 via a bending portion 19 (see FIG. 11). By bending the bending portion 19, the jaw assembly 1 can be oriented in an appropriate direction.

[0021] In the jaw assembly 1, a pair of jaws 3 and 5 (FIGS. 3 to 5) is rotatably supported by a support portion 7. This support allows the pair of jaws 3 and 5 to open and close relative to each other.

[0022] The pair of jaws 3 and 5 have gripping surfaces 3a and 5a that can grip a wire such as suture thread 15 (see FIG. 6) between them when they are closed. The gripping surfaces 3a and 5a are surfaces that come together when the jaws 3 and 5 are closed.

[0023] In this embodiment, the suture 15 is gripped while crossing the gripping surfaces 3a and 5a. The direction in which the suture 15 crosses the gripping surfaces 3a and 5a refers to a direction intersecting the longitudinal direction (the vertical direction in FIG. 1) of the gripping surfaces 3a and 5a, i.e., a diagonal direction (the diagonal direction in FIG. 1) and a width direction (the horizontal direction in FIG. 1). In this embodiment, the diagonal direction refers to a direction inclined at 45 degrees to the longitudinal direction. When the suture 15 crosses the width direction, the suture 15 forms a zigzag shape with respect to the width direction, as will be described later (see FIG. 7), but the direction may be a direction crossing the direction formed by the start point and end point of the suture 15 located between the gripping surfaces 3a and 5a.

[0024] In this embodiment, the set of jaws is composed of a pair of jaws 3 and 5, but it can also be composed of three or more jaws. In this case, a gripping surface is provided between adjacent jaws in the circumferential direction, etc. For example, when three jaws are provided, the three jaws are arranged in the circumferential direction like a well-known three-jaw chuck, and each jaw is provided with two gripping surfaces. The two gripping surfaces of each jaw are configured to mate with the gripping surfaces of the jaws adjacent to them in the circumferential direction.

[0025] The gripping surfaces 3a and 5a of the pair of jaws 3 and 5 are formed so that their widths gradually narrow toward the tips. A plurality of protrusions 9 and 11 protrude from these gripping surfaces 3a and 5a, respectively. Therefore, the gripping surfaces 3a and 5a are configured as uneven surfaces by having the protrusions 9 and 11. The protrusions 9 and 11 of the gripping surfaces 3a and 5a are designed to mesh with each other when the jaws 3 and 5 are in a closed state.

[0026] The multiple protrusions 9 and 11 on the gripping surfaces 3a and 5a have the same configuration except for the fact that they are configured to interlock (the positions of the protrusions 9 are offset). Therefore, with regard to the protrusions 9 on the gripping surfaces 3a and 5a, the description will basically focus on the protrusions 9 on one of the gripping surfaces 3a, and the protrusions 11 on the other gripping surface 5a will be described as needed, with only the reference numerals shown in parentheses.

[0027] As shown in Figures 1 and 2, the multiple protrusions 9 (11) on the gripping surface 3a (5a) are provided with the same shape across the entire gripping surface 3a (5a). However, the protrusions 9 (11) do not have to be the same shape. The multiple protrusions 9 (11) are discontinuous, i.e., independent, in the longitudinal direction (vertical direction in Figure 1) and transverse direction of the gripping surface 3a (5a). These protrusions 9 (11) are arranged independently and connected in the longitudinal and width directions of the gripping surface 3a (5a).

[0028] Each of the protrusions 9 is formed in a pyramidal shape, particularly a quadrangular pyramidal shape. The shape of the protrusions 9 (11) can be set appropriately, and other conical shapes, such as a circular cone, an elliptical cone, or a frustum, can also be used.

[0029] Each of the protrusions 9 (11) has an inclined surface 9a (11a) that is inclined so as to converge to a tip in the protruding direction. In the protrusions 9 (11) of this embodiment, the tip 9b (11b) converges to the tip with a curvature. However, the tip 9b (11b) of the protrusions 9 (11) may also converge to the tip in a straight line.

[0030] The sides of the quadrangular pyramidal protrusions 9 (11) are oblique. Therefore, the corners of the protrusions 9 (11) in plan view are oriented in the longitudinal and width directions. The corners of adjacent protrusions 9 in plan view overlap each other.

[0031] As a result, a plurality of valleys 16 are provided between adjacent protrusions 9 (11) in the longitudinal direction, which is a direction intersecting the transverse direction. The valleys 16 are formed in a V-shape.

[0032] Between adjacent valley portions 16 in the transverse direction, a recess 13 is provided relative to the valley portion 16. The recess 13 is formed in a concave shape in the opposite direction to the protruding direction of the convex portion 9 (11) with the valley portion 16 as a boundary. The recess 13 is composed of a part of the slope 9a (11a) of the convex portion 9 (11) and a depression 14 that is further concave relative to the convex portion 9 (11). In this embodiment, the recess 13 is located between adjacent valley portions 16 in the longitudinal direction, width direction, and diagonal direction of the grip surface 3a (5a).

[0033] The pair of jaws 3 and 5 can grip a wire suture 15 between the inclined surfaces 9a and 11a of the interlocking convex portions 9 and 11. In addition to being gripped between the inclined surfaces 9a and 11a of the convex portions 9 and 11, the suture 15 is also gripped by being sandwiched between the opposing valley portions 16.

[0034] [Grip] Figure 6 is a side perspective view showing a portion of the jaw assembly of Figure 3 in a gripping state. Figure 7 is a front view showing the relationship between the gripping surfaces of the jaws of Figure 1 and the suture. Figure 8 is a front view showing the relationship between the gripping surfaces of the jaws of Figure 1 and the suture.

[0035] In the jaw assembly 1 of this embodiment, as shown in Fig. 6, when the pair of jaws 3 and 5 are closed, a flexible wire suture 15 extending transversely between the gripping surfaces 3a and 5a is grasped. At this time, the suture 15 first extends linearly in the transverse direction so as to bridge the valley portion 16 on one or both of the gripping surfaces 3a and 5a of the jaws 3 and 5 in the open state, as shown by the two-dot chain line in Fig. 7 and the thick line in Fig. 8. When the gripping surfaces 3a and 5a are closed in this state, the suture 15 is clamped between the slopes 9a and 11a of the convex portions 9 and 11, for example, as shown in Fig. 6. Note that the two-dot chain line in Fig. 7 is illustrated parallel to the suture 15 for ease of visibility.

[0036] As shown in FIG. 7, when suture thread 15 is grasped across the width of jaw 3, perpendicular to the longitudinal direction, suture thread 15 bridging valley 16 along the width before gripping surfaces 3a and 5a close is pushed aside to bypass protrusions 9 and 11 of gripping surfaces 3a and 5a as they enter opposing recesses 13.

[0037] In this roundabout state, the suture 15 is sandwiched between the inclined surfaces 9a and 11a. As a result, the suture 15 is gripped in a zigzag pattern in a plan view. Therefore, the suture 15 stretches in a zigzag pattern in the width direction between the gripping surfaces 3a and 5a.

[0038] At the same time, the entry of the protrusion 9 or 11 into the opposing recess 13 on one of the gripping surfaces 3a and 5a of the jaws 3 and 5 causes the suture 15 to be pushed into the recess 13 adjacent to the valley 16, or at least to be subjected to a force in the pushing direction. In either case, the suture 15 is pressed against the valley 16.

[0039] Therefore, when the suture 15 is held by the gripping surfaces 3a and 5a, it is possible to increase the frictional force against the force in the direction of pulling out the suture 15 without increasing the clamping force of the gripping surfaces 3a and 5a. As a result, in this embodiment, it is possible to more reliably hold the flexible suture 15 between the gripping surfaces 3a and 5a.

[0040] As shown in Figure 8, when suture thread 15 is grasped so as to cross jaw 3 diagonally, before gripping surfaces 3a and 5a close, suture thread 15 bridging valley portion 16 along the diagonal direction is clamped between opposing slopes 9a and 11a as protrusions 9 and 11 arranged diagonally enter opposing recesses 13.

[0041] At this time, the suture 15 extends linearly in an oblique direction in a plan view, but is either pushed into the recess 13 adjacent to the valley 16, or is not pushed in at all but is subjected to a force in the pushing direction. Therefore, as in the case of Figure 7, the suture 15 is pressed against the valley 16.

[0042] Furthermore, on both sides of valley portion 16 in the diagonal direction, slopes 9a and 11a of protrusions 9 and 11 that clamp suture 15 are inclined in opposite directions. As a result, suture 15 is pulled in opposite directions, perpendicular to the diagonal direction, on both sides of valley portion 16, as indicated by the arrows in Figure 8. As a result, suture 15 is gripped in a substantially zigzag pattern in a plan view.

[0043] Therefore, even in such a case, when the suture 15 is held by the gripping surfaces 3a and 5a, the frictional force against the force in the direction of pulling out the suture 15 can be increased without increasing the clamping force of the gripping surfaces 3a and 5a. As a result, the flexible suture 15 can be more reliably held between the gripping surfaces 3a and 5a.

[0044] [Experimental Results] Fig. 9 is a perspective view of a jaw according to a comparative example, and Fig. 10 is a side view showing a part of the jaw according to the comparative example.

[0045] The gripping force was experimentally determined for the comparative example and the example shown in Figures 9 and 10. In the comparative example, the convex portions 9A (11A) on the gripping surface 3Aa (5Aa) of one jaw 3A (5A) are arranged at intervals without overlapping in either the longitudinal direction or the perpendicular direction of the jaw 3A (5A).

[0046] When jaw 3A and mating jaw 5A are closed, a linear groove 16A is formed in the diagonal direction, which may result in insufficient gripping of suture 15. The configurations other than gripping surfaces 3Aa and 5Aa are the same in the comparative example and the example.

[0047] Fig. 11 is an explanatory diagram showing an experimental state of the gripping force of the jaw assembly according to the embodiment. Figs. 12(A) to 12(D) are explanatory diagrams showing a part of an experimental state of the gripping force when sutures in different directions are gripped by different parts of the jaw assembly. Fig. 13 is a chart showing experimental data of the gripping force of the jaw assembly of Figs. 12(A) to 12(D).

[0048] As shown in FIGS. 11 to 13, in the experiment, the tensile force applied to the suture 15 grasped by the jaw assembly 1 was determined as the grasping force.

[0049] In this experiment, jaw assembly 1 was supported on shaft 17 via bending portion 19, and load meters 23 and 25 were connected to push-pull wire 21 that opens and closes jaws 3 and 5, and to suture thread 15 held by jaws 3 and 5, respectively. Jig 29 was attached to shaft 17 to prevent bending portion 19 from moving.

[0050] Then, a specified load was applied to the push-pull wire 21 using the load meter 23, a tensile force was applied to the 6-0 suture 15 between the jaws 3 and 5, and the tensile force when slippage occurred in the suture 15 was measured.

[0051] The gripping direction of the suture 15 with respect to the jaws 3 and 5 was set to two types: 45° in Figures 12(A) and (B) and 90° in Figures 12(C) and (D) with respect to the longitudinal axial direction of the jaws 3 and 5. The 45° gripping direction is a diagonal direction, and the 90° gripping direction is the width direction. The gripping position of the suture 15 with respect to the jaws 3 and 5 was set to two types: the base of the teeth on the base side in Figures 12(A) and (C) and the tip of the teeth on the tip side in Figures 12(B) and (D).

[0052] The measurement results are shown in the table in Figure 13. That is, in the 45° gripping direction, the gripping force of the comparative example was 0.02 N at the tooth tip and 0.00 N at the tooth base, while the gripping force of the example was 1.89 N at the tooth tip and 2 N or more at the tooth base.

[0053] Furthermore, in the 90° gripping direction, the gripping force of the comparative example was 0.82 N at the tooth tip and 0.58 N at the tooth base, whereas the gripping force of the example was 2 N or more at the tooth tip and 2 N or more at the tooth base.

[0054] As a result, the jaw assembly 1 of the embodiment can grip the suture 15 more reliably than when the suture 15 is gripped through a linear groove 16A as in the comparative example.

[0055] As described above, the jaw assembly 1 of this embodiment includes a plurality of protrusions 9 that protrude from the gripping surfaces 3a and 5a of a pair of jaws 3 and 5, respectively, so as to be able to interlock with each other and that are discontinuous in a direction transverse to the gripping surfaces 3a and 5a, a plurality of valleys 16 formed between adjacent protrusions 9 in a direction intersecting the transverse direction, and a plurality of recesses 13 formed relative to the valleys 16 between adjacent valleys 16 in the transverse direction.

[0056] Therefore, in this embodiment, the suture 15 can be pressed against the valley portion 16, and the flexible suture 15 can be more reliably gripped between the gripping surfaces 3a and 5a without increasing the gripping force.

[0057] The plurality of protrusions 9 each have inclined slopes 9a and 11a that converge to the tip in the protruding direction, and the wire 15 is clamped between the inclined surfaces 9a and 11a of the protrusions 9 that mesh with each other between a pair of jaws 3 and 5. In addition, on both sides of the valley portion 16 in the intersecting direction, the inclined surfaces 9a and 11a of the protrusions 9 that clamp the wire 15 are inclined in opposite directions.

[0058] Therefore, in this embodiment, the suture thread 15 in the gripped state can be made to have a zigzag shape or a substantially zigzag shape in the direction transverse to the gripping surfaces 3a and 5a in a planar view, making it possible to more reliably grip the flexible suture thread 15 between the gripping surfaces 3a and 5a.

[0059] Each of the protrusions 9 is pyramidal, particularly quadrangular pyramidal, with its sides aligned in the transverse direction in plan view, thereby ensuring that the gripped suture 15 is formed into a zigzag or substantially zigzag shape in plan view on the gripping surfaces 3 a and 5 a. [Explanation of symbols]

[0060] 1 Jaw assembly 3, 5 Joe 3a, 5a gripping surface 9, 11 Convex parts 13 Recess 15 Sutures (wire) 16 Valley

Claims

1. a pair of jaws having gripping surfaces capable of gripping a wire in a closed state; a plurality of protrusions projecting from the gripping surfaces of the pair of jaws so as to be able to engage with each other and being discontinuous in a direction transverse to the gripping surfaces; a plurality of valleys formed between adjacent protrusions in a direction intersecting the transverse direction; a plurality of recesses formed between adjacent valleys in the transverse direction and corresponding to the valleys; A jaw assembly comprising:

2. 2. The jaw assembly of claim 1, The plurality of protrusions each have an inclined surface that is inclined so as to converge to a tip end in a protruding direction, and the wire rod is clamped between the inclined surfaces of the protrusions that are mutually engaged between the pair of jaws. Jaw assembly.

3. 3. The jaw assembly of claim 2, On both sides of the valley portion in the transverse direction, the slopes of the protrusions that sandwich the wire rod are inclined in opposite directions. Jaw assembly.

4. The jaw assembly of claim 2 or 3, Each protrusion is pyramidal. Jaw assembly.

5. 5. The jaw assembly of claim 4, Each of the protrusions has a quadrangular pyramid shape, and a side in a plan view is aligned along the transverse direction. Jaw assembly.

6. A gripping surface structure applied to a set of jaws that grips a wire in a closed state, a gripping surface for gripping the wire; a plurality of protrusions protruding from the gripping surface and discontinuous in a direction transverse to the gripping surface; a plurality of valleys formed between adjacent protrusions in a direction intersecting the transverse direction; a plurality of recesses formed between adjacent valleys in the transverse direction and corresponding to the valleys; A gripping surface structure comprising:

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