MINIMAL ACCESS TOOL

• US 20120041450A1
• Filed: 04/13/2009
• Published: 02/16/2012
• Est. Priority Date: 04/11/2008
• Status: Active Grant

• Current Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Original Assignee: Board of Regents of the University of Michigan (University of Michigan)
• Inventors: Awtar, Shorya, Nielsen, Jens, Trutna, Tristan, Mansfield, Andrew, Abani, Rosa, Geiger, James, Quigley, Patrick
• Granted Patent: US 8,668,702 B2
• Time in Patent Office: Days
• US Class Current: 606/130
• CPC Class Codes: A61B 17/2909 Handles
• CPC Class Codes: A61B 2017/00323 Cables or rods
• CPC Class Codes: A61B 2017/00424 ergonomic, e.g. fitting in fist
• CPC Class Codes: A61B 2017/00442 connectable to wrist or forearm
• CPC Class Codes: A61B 2017/00464 for use with different instruments
• CPC Class Codes: A61B 2017/2917 with flexible part
• CPC Class Codes: A61B 2017/2929 with a head rotatable about the longitudinal axis of the shaft
• CPC Class Codes: A61B 2017/2931 with releasable head
• CPC Class Codes: A61B 2017/2937 with flexible part
• CPC Class Codes: A61B 2017/2939 Details of linkages or pivot points
• CPC Class Codes: A61B 2017/2944 Translation of jaw members
• CPC Class Codes: A61B 2034/306 Wrists with multiple vertebrae
• CPC Class Codes: A61B 34/70 Manipulators specially adapted for use in surgery
• CPC Class Codes: A61B 34/71 Manipulators operated by drive cable mechanisms
• CPC Class Codes: A61B 34/75 Manipulators having means for prevention or compensation of hand tremors
• CPC Class Codes: A61B 34/77 Manipulators with motion or force scaling

Abstract

A minimal access tool includes a frame arranged to be attached to an arm of a user, a tool shaft having a proximal end and a distal end, where the tool shaft proximal end is connected to the frame. The tool further includes an input joint having a first end connected to the frame and a second end arranged to receive user input, the input joint including a virtual center-of-rotation (VC) mechanism which provides a center of rotation that generally coincides with a wrist joint of the user. An output joint is connected to the tool shaft distal end, where the output joint is coupled to the input joint via a mechanical transmission connected therebetween to correlate motion of the input joint to motion of the output joint.

Claims

1. A minimal access tool, comprising:

a frame arranged to be attached to an arm of a user;

a tool shaft having a proximal end and a distal end, the tool shaft proximal end connected to the frame;

an input joint having a first end connected to the frame and a second end arranged to receive user input, the input joint including a virtual center-of-rotation (VC) mechanism which provides a center of rotation that generally coincides with a wrist joint of the user; and

an output joint connected to the tool shaft distal end, wherein the output joint is coupled to the input joint via a mechanical transmission connected therebetween to correlate motion of the input joint to motion of the output joint.

2. The tool according to claim 1, wherein the mechanical transmission comprises cables.

3. The tool according to claim 2, wherein the cables are routed through the tool shaft.

4. The tool according to claim 1, wherein the mechanical transmission includes a variable transmission ratio.

5. The tool according to claim 1, wherein the input joint second end comprises a floating member for receiving input from the user.

6. The tool according to claim 5, wherein the VC mechanism includes at least three links disposed between the input joint first end and the floating member, and the mechanical transmission includes cables which are connected between the floating member and the output joint, wherein axes of the at least three links intersect generally at the wrist joint of the user.

7. The tool according to claim 6, wherein the floating member includes at least one cam surface for preventing slack in the cables.

8. The tool according to claim 1, wherein the VC mechanism includes

a first intermediate member connected to the input joint first end by a first set of connectors and connected to the input joint second end by a second set of connectors;

and

a second intermediate member connected to the input joint first end by a third set of connectors and connected to the input joint second end by a fourth set of connectors, the mechanical transmission connected between the output joint and the first and second intermediate members,

wherein the first and fourth sets of connectors are complaint in only one rotational direction and the second and third sets of connectors are compliant in only another rotational direction, such that two degree of freedom rotational motion of the VC mechanism is decoupled into separate one degree of freedom rotations exhibited at the first and second intermediate members.

9. The tool according to claim 8, wherein the mechanical transmission includes cables and the first and second intermediate members each include at least one cam surface for preventing slack in the cables.

10. The tool according to claim 1, wherein the VC mechanism includes first and second connectors connected between the input joint first and second ends, the mechanical transmission connected between the output joint and the input joint first end, wherein the first connector is compliant about only one rotational direction and the second connector is compliant about only another rotational direction, such that two degree of freedom rotational motion of the VC mechanism is decoupled into separate one degree of freedom rotations exhibited at the first and second connectors.

11. The tool according to claim 10, wherein the mechanical transmission includes cables which are connected to at least one input pulley at the input joint and at least one output pulley at the output joint.

12. The tool according to claim 1, further comprising an end effector connected to the output joint.

13. The tool according to claim 12, wherein the end effector is detachable from the output joint.

14. The tool according to claim 12, wherein the end effector includes jaws capable of opening and closing movements.

15. The tool according to claim 14, further comprising a lever adjacent the input joint second end and in communication with the end effector for actuating the opening and closing movements of the jaws.

16. The tool according to claim 12, wherein the end effector comprises a first ring connected to the tool shaft and capable of a first rotation about a first rotational axis, and a second ring connected to the first ring and the end effector and capable of a second rotation about a second rotational axis, creating a center of rotation acting at an intersection of the axes and mechanically decoupling the first and second rotations.

17. The tool according to claim 16, wherein the mechanical transmission includes cables, wherein the first ring is actuated by a pair of cables attached to the first ring generally at the location of the first rotational axis, and the second ring is actuated by a pair of cables attached to the second ring at generally the same height as the first ring and generally at the location of the second rotational axis.

18. The tool according to claim 1, further comprising a quick release mechanism for disengaging the tool shaft from the frame.

19. A minimal access tool, comprising:

a frame arranged to be attached to an arm of a user;

a tool shaft having a proximal end and a distal end, the tool shaft proximal end connected to the frame;

an input joint having a first end connected to the frame and a second end arranged to receive user input, the input joint including a virtual center-of-rotation (VC) mechanism which provides a center of rotation that generally coincides with a wrist joint of the user and remains stationary throughout the range of motion of the VC mechanism, the VC mechanism including a pitch connector and a yaw connector connected between the input joint first and second ends, wherein the pitch connector is compliant about only a yaw axis with respect to the frame and the yaw connector is compliant about only a pitch axis with respect to the frame, thereby decoupling two degree of freedom rotational motion of the VC mechanism into separate one degree of freedom rotations exhibited at the pitch and yaw connectors; and

an output joint connected to the tool shaft distal end, wherein the output joint is mechanically coupled to the input joint via cables to correlate motion of the input joint to motion of the output joint.

20. The tool according to claim 19, further comprising:

a pitch axis shaft for coupling the pitch connector to the frame;

a yaw axis shaft for coupling the yaw connector to the frame;

a pitch axis pulley received on the pitch axis shaft; and

a yaw axis pulley received on the yaw axis shaft,

wherein the cables are connected to the pitch and yaw axis pulleys for transmitting decoupled pitch and yaw rotations, respectively, to the output joint.

21. A minimal access tool arranged to be supported on an external structure, comprising:

a frame arranged to be attached to an arm of a user;

a tool shaft having a proximal end and a distal end, the tool shaft proximal end connected to the frame;

an input joint having a first end connected to the frame and a second end arranged to receive user input, the input joint including a virtual center-of-rotation (VC) mechanism which provides a center of rotation that generally coincides with a wrist joint of the user;

an output joint connected to the tool shaft distal end, wherein the output joint is coupled to the input joint via a mechanical transmission connected therebetween to correlate motion of the input joint to motion of the output joint; and

an interface mechanism connecting the frame and the external structure.

22. The tool according to claim 21, wherein the interface mechanism supports the weight of the tool without constraining the mobility of the tool.