Tool with end effector force limiter

• US 20080255608A1
• Filed: 04/16/2007
• Published: 10/16/2008
• Est. Priority Date: 04/16/2007
• Status: Active Grant

• Current Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Original Assignee: Intuitive Surgical Operations, Inc. (Intuitive Surgical Holdings, LLC)
• Inventors: Bertsch, Karrie S., Hinman, Cameron D.
• Granted Patent: US 8,409,244 B2
• Time in Patent Office: Days
• US Class Current: 606/205
• CPC Class Codes: A61B 17/00 Surgical instruments, devices or methods, e.g. tourniquets A61B18/00 takes precedence; contraceptive devices, pessaries, or applicators therefor A61F6/00; eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 17/29 Forceps for use in minimally invasive surgery
• CPC Class Codes: A61B 2017/2837 with a locking ratchet
• CPC Class Codes: A61B 2017/2927 the angular position of the head being adjustable with respect to the shaft
• CPC Class Codes: A61B 2017/2929 with a head rotatable about the longitudinal axis of the shaft
• CPC Class Codes: A61B 2017/2946 Locking means
• CPC Class Codes: A61B 90/03 Automatic limiting or abutting means, e.g. for safety

Abstract

The invention provides surgical or diagnostic tools and associated methods that offer improved user control for operating remotely within regions of the body. In some embodiments these tools include a proximally-located actuator for the operation of a distal end effector, as well as proximally-located actuators for articulational and rotational movements of the end effector. Control mechanisms and methods refine operator control of end effector actuation and of these articulational and rotational movements. A force limiter mechanism protects the end effector and manipulated objects from the harm of potentially excessive force applied by the operator. The tool may also include other features. A multi-state ratchet for end effector actuation provides enablement-disablement options with tactile feedback. An articulation lock allows the fixing and releasing of both neutral and articulated configurations of the tool and of consequent placement of the end effector. A rotation lock provides for enablement and disablement of rotatability of the end effector.

Claims

1. A surgical or diagnostic tool comprising:

an end effector at a distal end of the tool;

an end effector actuator at a proximal end of the tool, the end effector actuator being operatively connected to the end effector through a linkage to deliver an actuation force from the end effector actuator to the end effector in response to movement of the end effector actuator; and

a force limiter adapted to establish an upper limit on the actuation force that may be delivered to the end effector by the end effector actuator.

2. The tool of claim 1 further comprising a handle supporting the end effector actuator, the end effector actuator being movable with respect to the handle.

3. The tool of claim 1 wherein the force limiter comprises a stop element engagable with the end effector actuator to stop its motion.

4. The tool of claim 1 wherein the force limiter is adapted to deform in response to actuation force delivered by the end effector actuator.

5. The tool of claim 4 wherein the force limiter comprises a spring in the linkage.

6. The tool of claim 5 wherein the spring is pre-loaded to a pre-determined stress within the linkage.

7. The tool of claim 6 wherein the spring is formed from a superelastic shape memory material treated so as to bend when the upper limit of the actuation force is applied to the end effector by the end effector actuator.

8. The tool of claim 7 wherein the superelastic shape memory material has a plateau stress level, the spring being disposed within the linkage so at to be pre-loaded at about the plateau stress level.

9. The tool of claim 5 wherein the force limiter further comprises a stop element engagable with the end effector actuator to stop its motion.

10. The tool of claim 1 wherein the end effector is operably connected to the end effector actuator at least in part through the force limiter.

11. The tool of claim 10 wherein the force limiter is disposed between the end effector actuator and the linkage.

12. The tool of claim 10 wherein the end effector actuator is operably connected to the linkage such that movement of the end effector actuator moves the linkage and such that movement of the end effector actuator with respect to the linkage varies when the upper limit of the actuation force is reached.

13. The tool of claim 1 where the force limiter comprises a tension bearing member in the linkage, the member comprising a superelastic shape memory material.

14. The tool of claim 13 where the tension bearing member is pre-stretched to a pre-determined stress within the linkage.

15. The tool of claim 14 where the predetermined stress corresponds to about the upper limit of the actuation force that is to be applied to the end effector by the end effector actuator.

16. The tool of claim 1 wherein the end effector comprises a movable force delivery surface.

17. The tool of claim 16 wherein the end effector comprises a pair of jaws.

18. The tool of claim 1 further comprising:

a shaft disposed between the end effector and the end effector actuator, and

an articulation mechanism for manipulating angular orientation of the end effector with respect to the shaft, the articulation mechanism comprising a proximal link and a distal link spaced apart from the proximal link, such that movement of the proximal link causes corresponding relative movement of the distal link.

19. A method of operating a surgical or diagnostic tool, the tool comprising an end effector in a distal portion and an end effector actuator in a proximal portion, the method comprising:

placing the end effector at a target site;

applying an actuation force to the end effector actuator;

delivering at least some of the actuation force through the end effector to the target site; and

limiting the magnitude of the delivered actuation force to an upper limit.

20. The method of claim 19 wherein applying an actuation force comprises moving the end effector actuator.

21. The method of claim 20 wherein the tool further comprises a handle supporting the end effector actuator, the step of moving the end effector actuator comprising moving the end effector actuator with respect to the handle.

22. The method of claim 20 wherein the tool further comprises a stop element, the moving step comprising engaging the end effector actuator with the stop element.

23. The method of claim 19 wherein the tool further comprises a force limiter, the limiting step further comprising deforming the force limiter.

24. The method of claim 23 wherein the force limiter comprises a spring, the limiting step comprising deforming the spring.

25. The method of claim 24 wherein the deforming step comprises increasing strain of the spring without substantially increasing stress of the spring.

26. The method of claim 23 wherein the force limiter comprises a tension bearing member, the limiting step comprising tensioning the member.

27. The method of claim 26 wherein the deforming step comprises the tension bearing member stretching in response to tensioning.

28. The method of claim 27 wherein the step of limiting the magnitude of the delivered actuation force comprises the stretching of the tension bearing member.

29. The method of claim 19 wherein the step of delivering the force comprises moving the end effector, the limiting step comprising ceasing movement of the end effector despite continued movement of the end effector actuator.

30. The method of claim 19 wherein the step of delivering the force to the target site comprises moving the end effector.

31. The method of claim 30 wherein the end effector comprises jaws, the step of delivering a force to the target site comprising moving the end effector jaws.

32. The method of claim 19 wherein the tool further comprises a handle supporting the end effector actuator and a shaft disposed between the handle and the end effector, the method further comprising moving the handle angularly with respect to the shaft to move the end effector angularly with respect to the shaft.