Articulable wrist with flexible member and pivot guides

1. An articulable wrist for an end effector, comprising:

a first linkage;

a second linkage rotatably coupled to the first linkage at a first articulation joint;

a flexible member extending at least partially through a central channel cooperatively defined by the first and second linkages; and

a first pivot guide rotatably coupled to the second linkage at the first articulation joint and rotatable about a first pivot axis extending through the first articulation joint, the first pivot guide defining a central aperture alignable with the central channel and sized to accommodate the flexible member therethrough,

wherein the first pivot guide is constrained to pivot only about the first pivot axis and comprises first and second matable members that cooperatively define the central aperture when mated, and

wherein the first pivot guide supports an outer diameter of the flexible member at the first articulation joint and thereby prevents the flexible member from flexing beyond the first pivot axis during articulation.

2. The articulable wrist of claim 1 , further comprising an axially-extending conduit defined in the flexible member to receive a closure cable used to actuate jaws of the end effector, wherein the pivot guide supports the outer diameter of the flexible member at the first articulation joint and prevents a centerline of the closure cable from deviating below the first pivot axis during clamping.

3. The articulable wrist of claim 1 , wherein the second linkage comprises:

a main body that defines a portion of the central channel;

a pair of lobes extending from the main body and laterally offset from each other; and

an aperture defined in each lobe and sized to rotatably receive a portion of the first pivot guide.

4. The articulable wrist of claim 3 , wherein the first pivot guide comprises:

a cylindrical body that defines the central aperture and has first and second ends rotatably received into the aperture defined on each lobe; and

a protrusion extending outward from each of the first and second ends and providing a first axle extending along the first pivot axis, wherein the first linkage is rotatably coupled to the second linkage at the first axle.

5. The articulable wrist of claim 3 , wherein the first pivot guide comprises:

an annular body that defines the central aperture; and

opposing pins extending radially outward from the annular body at angularly opposite sides of the annular body, wherein the opposing pins are rotatably received into the aperture defined on each lobe.

6. The articulable wrist of claim 3 , wherein the first pivot guide comprises

a protrusion extending from an end of each matable member and providing a first axle extending along the first pivot axis, wherein the first linkage is rotatably coupled to the second linkage at the first axle.

7. The articulable wrist of claim 3 , wherein the first pivot guide comprises:

an annular body that defines the central aperture;

opposing cylindrical heads positioned at angularly opposite sides of the annular body and rotatably received into the aperture defined on each lobe; and

opposing pins extending radially outward from the each cylindrical head and providing a first axle extending along the first pivot axis, wherein the first linkage is rotatably coupled to the second linkage at the first axle.

8. The articulable wrist of claim 7 , further comprising one or more dimples protruding radially inward from the annular body and into the central aperture.

9. The articulable wrist of claim 1 , wherein the second linkage comprises:

a first intermediate part providing a first lobe; and

a second intermediate part providing a second lobe laterally offset from the first lobe when the first and second intermediate parts are mated to form the second linkage and define the central channel.

10. The articulable wrist of claim 9 , wherein the first pivot guide comprises:

an annular body that defines the central aperture; and

opposing disc-shaped heads positioned at angularly opposite sides of the annular body and rotatably receivable within a bearing pocket defined on a corresponding one of the first or second lobes, wherein mating the first and second intermediate parts secures the first pivot guide to the articulable wrist.

11. The articulable wrist of claim 1 , wherein the second linkage comprises a main body that defines a portion of the central channel, a pair of lobes extending from the main body and laterally offset from each other, and one or more arcuate slots defined in each lobe, and

wherein the first pivot guide comprises two or more pins received within and extending between the one or more arcuate slots defined in each lobe, wherein the two or more pins are angularly offset from each other to define the central aperture.

12. The articulable wrist of claim 1 , further comprising:

a third linkage rotatably coupled to the second linkage at a second articulation joint and cooperatively defining the central channel with the first and second linkages; and

a second pivot guide rotatably coupled to the second linkage at the second articulation joint and rotatable about a second pivot axis extending through the second articulation joint, the second pivot guide defining a central aperture alignable with the central channel and sized to accommodate the flexible member therethrough,

wherein the second pivot guide is constrained to pivot only about the second pivot axis, and

wherein the second pivot guide supports the outer diameter of the flexible member at the second articulation joint and prevents the flexible member from flexing beyond the second pivot axis during articulation.

13. The articulable wrist of claim 12 , wherein the second linkage comprises:

a main body that defines a portion of the central channel;

a pair of distally extending lobes extending distally from the main body and laterally offset from each other;

a pair of proximally extending lobes extending proximally from the main body and laterally offset from each other, wherein the pair of proximally extending lobes are angularly offset from the pair of distally extending lobes by 90°;

an aperture defined in each distally extending lobe and sized to rotatably receive a portion of the first pivot guide; and

an aperture defined in each proximally extending lobe and sized to rotatably receive a portion of the second pivot guide.

14. The articulable wrist of claim 1 , wherein the first pivot guide is made of a material selected from the group consisting of an electrically-conductive material, a non-conductive material, a plastic, a metal, a composite material, an elastomer, and any combination thereof.

15. A surgical tool, comprising:

a drive housing;

an elongate shaft that extends from the drive housing;

an end effector arranged at an end of the elongate shaft;

an articulable wrist that interposes the end effector and the elongate shaft, the articulable wrist including:

a first linkage;

a second linkage rotatably coupled to the first linkage at a first articulation joint;

a flexible member extending at least partially through a central channel cooperatively defined by the first and second linkages; and

a first pivot guide rotatably coupled to the second linkage at the first articulation joint and rotatable about a first pivot axis extending through the first articulation joint, the first pivot guide defining a central aperture alignable with the central channel and sized to accommodate the flexible member therethrough,

wherein the first pivot guide is constrained to pivot only about the first pivot axis and further comprises first and second matable members that cooperatively define the central aperture when mated, and

wherein the first pivot guide supports an outer diameter of the flexible member at the first articulation joint and thereby prevents the flexible member from flexing beyond the first pivot axis during articulation.

16. The surgical tool of claim 15 , wherein the end effector includes jaws actuatable to open and close, the surgical tool further comprising:

a closure cable extending from the drive housing to the end effector and actuatable to close the jaws, wherein the closure cable extends through an axially-extending conduit defined in the flexible member, and

wherein the pivot guide supports the outer diameter of the flexible member at the first articulation joint and prevents a centerline of the closure cable from deviating below the first pivot axis during closing.

17. The surgical tool of claim 15 , wherein the second linkage comprises:

a main body that defines a portion of the central channel;

a pair of lobes extending from the main body and laterally offset from each other; and

an aperture defined in each lobe and sized to rotatably receive a portion of the first pivot guide.

18. The surgical tool of claim 17 , wherein the first pivot guide comprises

a protrusion extending from an end of each matable member and providing a first axle extending along the first pivot axis, wherein the first linkage is rotatably coupled to the second linkage at the first axle.

19. The surgical tool of claim 17 , wherein the first pivot guide comprises:

an annular body that defines the central aperture; and

one or more dimples protruding radially inward from the annular body and into the central aperture.

20. The surgical tool of claim 15 , wherein the second linkage comprises a first intermediate part providing a first lobe, and a second intermediate part providing a second lobe laterally offset from the first lobe when the first and second intermediate parts are mated to form the second linkage and define the central channel, and

wherein the first pivot guide comprises an annular body that defines the central aperture, and opposing disc-shaped heads positioned at angularly opposite sides of the annular body and rotatably receivable within a bearing pocket defined on a corresponding one of the first or second lobes.

21. A method of operating a surgical tool, comprising:

positioning the surgical tool adjacent a patient for operation, the surgical tool including a drive housing, an elongate shaft that extends from the drive housing, an end effector arranged at an end of the elongate shaft, and a wrist that interposes the end effector and the elongate shaft and includes:

a first linkage;

a second linkage rotatably coupled to the first linkage at a first articulation joint;

a flexible member extending at least partially through a central channel cooperatively defined by the first and second linkages; and

a first pivot guide rotatably coupled to the second linkage at the first articulation joint and rotatable about a first pivot axis extending through the first articulation joint, the first pivot guide defining a central aperture alignable with the central channel and sized to accommodate the flexible member therethrough, wherein the first pivot guide is constrained to pivot only about the first pivot axis and further comprises first and second matable members that cooperatively define the central aperture when mated;

articulating the wrist and simultaneously bending the flexible member within the central channel; and

supporting an outer diameter of the flexible member at the first articulation joint with the first pivot guide and thereby preventing the flexible member from flexing beyond the first pivot axis during articulation.

22. The method of claim 21 , wherein the wrist further includes a third linkage rotatably coupled to the second linkage at a second articulation joint and cooperatively defining the central channel with the first and second linkages, and a second pivot guide rotatably coupled to the second linkage at the second articulation joint and rotatable about a second pivot axis extending through the second articulation joint, the second pivot guide defining a central aperture alignable with the central channel and sized to accommodate the flexible member therethrough, the method further comprising:

actuating a closure cable extending from the drive housing to the end effector to close jaws of the end effector, wherein the closure cable extends through a first axially-extending conduit defined in the flexible member;

supporting the outer diameter of the flexible member at the first articulation joint with the pivot guide and thereby preventing a centerline of the closure cable from deviating below the first pivot axis during closing;

actuating an open cable extending from the drive housing to the end effector to open the jaws, wherein the open cable extends through a second axially-extending conduit defined in the flexible member angularly offset from the first axially-extending conduit by 90°; and

supporting the outer diameter of the flexible member at the second articulation joint with the second pivot guide and thereby preventing a centerline of the open cable from deviating across the second pivot axis during opening.