Driving arrangement for articulating a surgical instrument

Patent metadata

Field	Value
Publication number	US-11129686-B2
Application number	US-201716340254-A
Country	US
Kind code	B2
Filing date	Oct 6, 2017
Priority date	Oct 14, 2016
Publication date	Sep 28, 2021
Grant date	Sep 28, 2021

Abstract

A robotic surgical instrument comprising a shaft, a first end effector element, an articulation connecting the first end effector element to a distal end of the shaft, the first end effector element being movable relative to the articulation, and a drive mechanism at a proximal end of the shaft. The drive mechanism comprises a first actuator connected to the first end effector element by a first pair of driving elements. The first pair of driving elements are configured such that a tension force applied by the first actuator to a first one of the first pair of driving elements causes the first end effector element to move relative to the articulation in a first motion direction, and the tension force applied to a second one of the first pair of driving elements causes the first end effector element to move relative to the articulation in a second motion direction. The first one of the first pair of driving elements has a first path between the first actuator and the first end effector element, and the second one of the first pair of driving elements has a second path between the first actuator and the first end effector element. The first path has a lower tension force loss than the second path such that the first motion direction transfers a greater proportion of the tension force to the first end effector element than the second motion direction.

First claim

The invention claimed is:

1. A robotic surgical instrument comprising:
a shaft;
a first end effector element;
an articulation connecting the first end effector element to a distal end of the shaft, the first end effector element movable relative to the articulation; and
a drive mechanism at a proximal end of the shaft comprising a first actuator, the first actuator being connected to the first end effector element by a first pair of driving elements, the first pair of driving elements being configured such that a tension force applied by the first actuator to a first one of the first pair of driving elements causes the first end effector element to move relative to the articulation in a first motion direction, and the tension force applied to a second one of the first pair of driving elements causes the first end effector element to move relative to the articulation in a second motion direction;
wherein the first one of the first pair of driving elements has a first path between the first actuator and the first end effector element, and the second one of the first pair of driving elements has a second path between the first actuator and the first end effector element, the first path having a lower tension force loss than the second path such that the first motion direction transfers a greater proportion of the tension force to the first end effector element than the second motion direction.

2. A robotic surgical instrument as claimed in claim 1 , further comprising:
a second end effector element;
the articulation connecting the second end effector element to the distal end of the shaft, the second end effector element movable relative to the articulation; and
the drive mechanism comprising a second actuator, the second actuator being connected to the second end effector element by a second pair of driving elements, the second pair of driving elements being configured such that a tension force applied by the second actuator to a first one of the second pair of driving elements causes the second end effector element to move relative to the articulation in the second motion direction, and the tension force applied to a second one of the second pair of driving elements causes the second end effector element to move relative to the articulation in the first motion direction;
wherein the first one of the second pair of driving elements has a third path between the second actuator and the second end effector element, and the second one of the second pair of driving elements has a fourth path between the second actuator and the second end effector element, the third path having a lower tension force loss than the fourth path such that the second motion direction transfers a greater proportion of the tension force to the second end effector element than the first motion direction.

3. A robotic surgical instrument as claimed in claim 2 , wherein a contact length of the third path which contacts internal structure of the robotic surgical instrument is less than a contact length of the fourth path which contacts internal structure of the robotic surgical instrument.

4. A robotic surgical instrument as claimed in claim 2 , wherein an overall length of the third path is less than an overall length of the fourth path.

5. A robotic surgical instrument as claimed in claim 2 , wherein the first path matches the third path and the second path matches the fourth path.

6. A robotic surgical instrument as claimed in claim 2 , wherein the first one of the second pair of driving elements is constrained to move around J pulleys, and the second one of the second pair of driving elements is constrained to move around K pulleys, where J<K or J<K−1.

7. A robotic surgical instrument as claimed in claim 6 , wherein M=J, and N=K.

8. A robotic surgical instrument as claimed in claim 2 , wherein the first one of the second pair of driving elements has a larger diameter than the second one of the second pair of driving elements and/or wherein the first one of the second pair of driving elements is constructed of a smaller number of thicker strands than the second one of the second pair of driving elements.

9. A robotic surgical instrument as claimed in claim 2 , wherein the first end effector element is rotatable relative to the articulation about a first axis, and the first pair of driving elements is configured such that the tension force applied by the first actuator to the first one of the first pair of driving elements causes the first end effector element to rotate about the first axis in a first rotation direction, and the tension force applied to the second one of the first pair of driving elements causes the first end effector element to rotate about the first axis in a second rotation direction and the second end effector element is rotatable relative to the articulation about the first axis, and the second pair of driving elements is configured such that a tension force applied by the second actuator to the first one of the second pair of driving elements causes the second end effector element to rotate about the first axis in the second rotation direction, and the tension force applied to the second one of the second pair of driving elements causes the second end effector element to rotate about the first axis in the first rotation direction.

10. A robotic surgical instrument as claimed in claim 9 , configured such that a tension force applied by the first actuator to the first one of the first pair of driving elements causes the first end effector element to rotate towards the second end effector element, and a tension force applied by the second actuator to the first one of the second pair of driving elements causes the second end effector element to rotate towards the first end effector element.

11. A robotic surgical instrument as claimed in claim 9 , configured such that a tension force applied by the first actuator to the first one of the first pair of driving elements causes the first end effector element to rotate away from the second end effector element, and a tension force applied by the second actuator to the first one of the second pair of driving elements causes the second end effector element to rotate away from the first end effector element.

12. A robotic surgical instrument as claimed in claim 9 , wherein the first and second end effector elements are opposing first and second jaws of an end effector.

13. A robotic surgical instrument as claimed in claim 1 , wherein a contact length of the first path which contacts internal structure of the robotic surgical instrument is less than a contact length of the second path which contacts internal structure of the robotic surgical instrument.

14. A robotic surgical instrument as claimed in claim 1 , wherein an overall length of the first path is less than an overall length of the second path.

15. A robotic surgical instrument as claimed in claim 1 , wherein the first one of the first pair of driving elements is constrained to move around M pulleys, and the second one of the first pair of driving elements is constrained to move around N pulleys, where M<N or M<N−1.

16. A robotic surgical instrument as claimed in claim 1 , wherein the first one of the first pair of driving elements has a larger diameter than the second one of the first pair of driving elements and/or wherein the first one of the first pair of driving elements is constructed of a smaller number of thicker strands than the second one of the first pair of driving elements.

17. A robotic surgical instrument as claimed in claim 1 , wherein the first and second one of each pair of driving

Assignees

• Cmr Surgical Ltd

Inventors

• Chaplin Ben Robert
• Henrywood Ross Hamilton
• Lodge Archie John Ralph

Classifications

• A61B34/71 Primary

  Manipulators operated by drive cable mechanisms · CPC title

• A61B17/0218

  for minimally invasive surgery (A61B17/0281, A61B17/0469, A61B17/12013, A61B17/1285, A61B17/29, A61B17/320016 take precedence) · CPC title

• A61B17/29

  Forceps for use in minimally invasive surgery · CPC title

• A61B2017/07285

  characterised by its cutter · CPC title

• A61B34/30

  Surgical robots · CPC title