Force transmission mechanism for surgical instrument, and related systems and methods
A force transmission mechanism for a surgical instrument includes a worm drive, a lever arm, and an actuation element. The lever arm may include a follower member at a first end of the lever arm. The follower member engages the worm drive and is configured to be driven by the worm drive. The actuation element is connected the lever arm. The actuation element is configured to transmit force to actuate an end effector of the surgical instrument. Rotational movement of the worm drive imparts translational movement to the actuation element via the lever arm.
1. A surgical instrument, comprising:
a shaft comprising a proximal end portion and a distal end portion,
an end effector coupled to the distal end portion of the shaft, and
a force transmission mechanism;
wherein the force transmission mechanism comprises a chassis, a worm drive, a lever arm, and an actuation element;
wherein the lever arm comprises a first end portion, a second end portion, an intermediate portion extending between the first end portion and the second end portion, and a follower member at the first end portion of the lever arm;
wherein the follower member is engaged with and driven by the worm drive;
wherein the lever arm is pivotable about a pivot axis at the second end portion of the lever arm;
wherein the actuation element operably couples the lever arm and the end effector;
wherein the actuation element is coupled to the lever arm at a location on the intermediate portion of the lever arm between the follower member and the pivot axis; and
wherein the follower member is drivable by rotational movement of the worm drive such that the rotational movement of the worm drive imparts pivoting movement to the lever arm about the pivot axis and translational movement to the actuation element via the lever arm.
2. The surgical instrument of claim 1 , wherein the worm drive comprises a threaded section defining a spiral groove between thread portions of the threaded section, and the follower member is received within the spiral groove of the worm drive.
3. The surgical instrument of claim 2 , wherein the threaded section comprises a central section and axial surfaces having a slope ranging from 10 degrees to 60 degrees.
4. The surgical instrument of claim 2 , wherein the spiral groove is wider at an outer radial surface of the worm drive than at a central section of the worm drive.
5. The surgical instrument of claim 2 , wherein the spiral groove is wider at a central section of the worm drive than at an outer radial surface of the worm drive.
6. The surgical instrument of claim 2 , wherein the follower member comprises a roller.
7. The surgical instrument of claim 2 , wherein the follower member comprises a pin.
8. The surgical instrument of claim 2 , wherein the follower member comprises a ball.
9. The surgical instrument of claim 1 , wherein the actuation element is a push/pull drive element.
10. The surgical instrument of claim 1 , wherein the surgical instrument is a non-wristed instrument.
11. The surgical instrument of claim 1 , further comprising a roll gear rotatably coupling the shaft relative to the chassis.
12. The surgical instrument of claim 1 ,
wherein the worm drive comprises gear teeth;
wherein the follower member comprises an engagement head; and
wherein the engagement head comprises gear teeth engaged with the gear teeth of the worm drive.
13. The surgical instrument of claim 1 , wherein the translational movement imparted to the actuation element by the worm drive is translational movement along an axial direction of the shaft.
14. The surgical instrument of claim 1 , wherein the force transmission mechanism comprises a coupler that couples the actuation element to the lever arm, the coupler being rotatable relative to the lever arm.
15. The surgical instrument of claim 1 , wherein the lever arm and the worm drive are coupled to a first face of the chassis, the proximal end portion of the shaft is coupled to a second face of the chassis opposite from the first face, and the actuation element extends from the lever arm through the chassis into the shaft.
16. An instrument, comprising:
a shaft comprising a proximal end portion and a distal end portion;
a jaw assembly coupled to the distal end portion of the shaft; and
a force transmission mechanism coupled to the proximal end portion of the shaft, the force transmission mechanism comprising a worm drive, a lever arm, and an actuation element, the lever arm comprising a follower member engaged with and driven by the worm drive, the actuation element operably coupling the lever arm and the jaw assembly;
wherein the lever arm is pivotable about a pivot axis in response to rotational movement of the worm drive;
the lever arm comprises an intermediate portion extending between the pivot axis and the follower member;
wherein the actuation element is coupled to the lever arm at a location on the intermediate portion of the lever arm between the follower member and the pivot axis, and
wherein the rotational movement of the worm drive imparts, via pivotable movement of the lever arm about the pivot axis, translational movement to the actuation element to actuate opening and closing of the jaw assembly.
17. The instrument of claim 16 , wherein the actuation element comprises a push/pull drive element.
18. The instrument of claim 16 , wherein the translational movement imparted to the actuation element by the worm drive to actuate opening and closing of the jaw assembly is translational movement along an axial direction of the shaft.
19. The instrument of claim 16 , wherein the force transmission mechanism comprises a coupler that couples the actuation element to the lever arm, the coupler being rotatable relative to the lever arm.
20. The instrument of claim 16 , wherein the force transmission mechanism comprises a chassis wall, the lever arm and the worm drive are coupled to a first face of the chassis wall, the proximal end portion of the shaft is coupled to a second face of the chassis wall opposite from the first face, and the actuation element extends from the lever arm through the chassis wall into the shaft.