Rotary input for lever actuation
A surgical instrument includes a surgical end effector coupled to an elongate tube and a rod that passes through the elongate tube. A control mechanism coupled to the elongate tube includes an input axle having a first axis of rotation, an idler pulley having a second axis of rotation perpendicular to the first axis, and a lever coupled to the rod and having a third axis of rotation parallel to the second axis. First and second capstans are fixed to the input axle. Cables pass over the idler pulley and are coupled to the lever. Rotating the input axle in a first direction winds a first cable onto the first capstan, rotates the lever, and moves the rod in a second direction. Rotating the input axle opposite the first direction winds a second cable onto the second capstan, rotates the lever, and moves the rod opposite the second direction.
1. A force transmission comprising:
an input axle having a first axis of rotation;
an idler pulley having a second axis of rotation substantially perpendicular to the first axis of rotation;
a lever having a third axis of rotation substantially parallel to the second axis of rotation;
a first capstan fixed to the input axle;
a second capstan fixed to the input axle;
a first cable that passes over the idler pulley with a first end coupled to the first capstan and a second end coupled to the lever such that rotating the input axle in a first direction winds the first cable onto the first capstan and rotates the lever in a second direction; and
a second cable that passes over the idler pulley with a third end coupled to the second capstan and a fourth end coupled to the lever such that rotating the input axle in a third direction opposite the first direction winds the second cable onto the second capstan and rotates the lever in a fourth direction opposite the second direction.
2. The force transmission of claim 1 wherein the lever is a first class lever.
3. The force transmission of claim 1 wherein the lever is a second class lever.
4. The force transmission of claim 1 further comprising an input connection for a rotary actuator coupled to an end of the input axle.
5. The force transmission of claim 4 further comprising a hand wheel coupled to an opposite end of the input axle from the input connection.
6. The force transmission of claim 1 further comprising a linkage that couples the lever to a rod that opens and closes an end effector of a mechanically actuated surgical instrument.
7. The force transmission of claim 1 wherein the first cable and the second cable are portions of a single cable.
8. The force transmission of claim 7 wherein the first capstan and the second capstan are portions of a single capstan.
9. A mechanically actuated surgical instrument comprising:
a surgical end effector;
an elongated tube coupled to the surgical end effector;
a rod coupled to the surgical end effector and passing through the elongated tube; and
a proximal control mechanism coupled to the elongated tube, the proximal control mechanism including
an input axle having a first axis of rotation,
an idler pulley having a second axis of rotation substantially perpendicular to the first axis of rotation,
a lever coupled to the rod and having a third axis of rotation substantially parallel to the second axis of rotation,
a first capstan fixed to the input axle,
a second capstan fixed to the input axle,
a first cable that passes over the idler pulley with a first end coupled to the first capstan and a second end coupled to the lever such that rotating the input axle in a first direction winds the first cable onto the first capstan, rotates the lever, and moves the rod in a second direction, and
a second cable that passes over the idler pulley with a third end coupled to the second capstan and a fourth end coupled to the lever such that rotating the input axle in a third direction opposite the first direction winds the second cable onto the second capstan, rotates the lever, and moves the rod in a fourth direction opposite the second direction.
10. The mechanically actuated surgical instrument of claim 9 wherein the lever is a first class lever.
11. The mechanically actuated surgical instrument of claim 9 wherein the lever is a second class lever.
12. The mechanically actuated surgical instrument of claim 9 the proximal control mechanism further including an input connection for a rotary actuator coupled to an end of the input axle.
13. The mechanically actuated surgical instrument of claim 12 the proximal control mechanism further including a hand wheel coupled to an opposite end of the input axle from the input connection.
14. The mechanically actuated surgical instrument of claim 9 wherein the rod opens and closes the surgical end effector.
15. The mechanically actuated surgical instrument of claim 9 wherein the first cable and the second cable are portions of a single cable.
16. The mechanically actuated surgical instrument of claim 15 wherein the first capstan and the second capstan are portions of a single capstan.
17. A method of transmitting force to a mechanically actuated surgical instrument, the method comprising:
rotating an input axle in a first direction to wind a first cable onto a first capstan fixed to the input axle, the input axle having a first axis of rotation;
passing the first cable over an idler pulley having a second axis of rotation substantially perpendicular to the first axis of rotation;
coupling the first cable to a lever to rotate the lever in a second direction, the lever having a third axis of rotation substantially parallel to the second axis of rotation;
rotating the input axle in a third direction opposite the first direction to wind a second cable onto a second capstan fixed to the input axle;
passing the second cable over the idler pulley; and
coupling the second cable to the lever to rotate the lever in a fourth direction opposite the second direction.
18. The method of claim 17 wherein the lever is a first class lever.
19. The method of claim 17 wherein the lever is a second class lever.
20. The method of claim 17 further comprising coupling the lever to a rod to close a surgical end effector when the lever is rotated in the second direction and open the surgical end effector when the lever is rotated in the fourth direction.
21. The method of claim 17 wherein the first cable and the second cable are portions of a single cable.
22. The method of claim 21 wherein the first capstan and the second capstan are portions of a single capstan.