Knife drive assembly for electrosurgical shears
A surgical instrument includes an end effector, a handle assembly, and a knife drive assembly. The end effector includes a pair of jaws, a knife, and an RF electrode assembly. The knife actuates between a pre-fired position and a fired position. An arm of the handle assembly is configured to pivot the second jaw between the open position and the closed position. The knife drive assembly includes an input assembly, a rotary assembly, and an output assembly. The input assembly travels a first proximal distance to rotate the rotary assembly. The rotary assembly rotates in response to travel of the input assembly along the first proximal distance to drive the output assembly a first distal distance to thereby actuate the knife from the pre-fired position toward the fired position. The first distal distance is greater than the first proximal distance.
1. A surgical instrument comprising:
(a) a housing extending distally into a first jaw;
(b) an arm coupled with the housing, wherein the arm extends distally into a second jaw, wherein the arm is configured to drive the second jaw between an open position and a closed position;
(c) a first electrode associated with either the first jaw or the second jaw;
(d) a knife configured to actuate within the first jaw and the second jaw between a pre-fired position and a fired position; and
(e) a knife drive assembly comprising:
(i) an input assembly,
(ii) a rotary assembly comprising a compound gear assembly, wherein the compound gear assembly comprises an input pinion and an output pinion configured to rotate unitarily, wherein the input pinion and the output pinion are coupled with a rotary pin comprising an angular locking body, and
(iii) an output assembly, wherein the input assembly is configured to travel a first proximal distance in order to rotate the rotary assembly, wherein the rotary assembly is configured to rotate in response to travel of the input assembly along the first proximal distance to drive the output assembly a first distal distance to thereby actuate the knife from the pre-fired position toward the fired position, wherein the first distal distance is greater than the first proximal distance.
2. The surgical instrument of claim 1 , wherein the input pinion and the output pinion cooperatively defines a locking through hole dimensioned to engage the angular locking body of the rotary pin.
3. The surgical instrument of claim 2 , wherein the rotary assembly further comprises a spacer interposed between the input pinion and the output pinion.
4. The surgical instrument of claim 3 , wherein the spacer also cooperatively defines the locking through hole.
5. The surgical instrument of claim 1 , wherein the first jaw, the second jaw, the knife, and the first electrode cooperatively form an end effector.
6. The surgical instrument of claim 1 , wherein the first jaw and the second jaw are pivotally coupled together.
7. The surgical instrument of claim 1 , wherein the first electrode is associated with the first jaw.
8. The surgical instrument of claim 7 , further comprising a second electrode associated with the second jaw.
9. The surgical instrument of claim 1 , wherein the housing and the arm cooperatively form a handle assembly.
10. The surgical instrument of claim 9 , wherein the housing and the arm are pivotally coupled together.
11. The surgical instrument of claim 1 , wherein the input drive is configured to translate relative to the housing.
12. The surgical instrument of claim 11 , wherein the input drive comprises a rack.
13. The surgical instrument of claim 12 , further comprising a trigger, wherein the rack is configured to selectively decouple with the trigger.
14. The surgical instrument of claim 1 , wherein the knife is configured to translate from the pre-fired position into the fired position.
15. The surgical instrument of claim 1 , wherein the input pinion is smaller than the output pinion.
16. A surgical instrument comprising:
(a) an end effector, wherein the end effector comprises:
(i) a first jaw,
(ii) a second jaw pivotably coupled with the first jaw, wherein the second jaw is operable to pivot between an open position and a closed position,
(iii) an electrode configured to deliver RF energy, and
(iv) a knife configured to actuate between a pre-fired position and a fired position;
(b) a handle assembly comprising a housing associated with the first jaw; and
(c) a knife drive assembly comprising:
(i) an input assembly,
(ii) a rotary assembly comprising a compound gear assembly comprising an input pinion, and output pinion, and a rotary pin comprising an angular locking body configured to rotate the input pinion and the output pinion unitarily, and
(iii) an output assembly, wherein the input assembly is configured to travel a first proximal distance in order to rotate the rotary assembly, wherein the rotary assembly is configured to rotate in response to travel of the input assembly along the first proximal distance to drive the output assembly a first distal distance to thereby actuate the knife from the pre-fired position toward the fired position, wherein the first distal distance is greater than the first proximal distance.
17. The surgical instrument of claim 16 , wherein the input pinion comprises 12 teeth.
18. The surgical instrument of claim 17 , wherein the output pinion comprises 15 teeth.
19. The surgical instrument of claim 17 , wherein the knife drive assembly further comprises a trigger coupled to the input assembly.
20. A surgical instrument comprising:
(a) an end effector comprising:
(i) a knife configured to actuate between a pre-fired position and a fired position, and
(ii) an electrode configured to transmit RF energy;
(b) a handle assembly comprising a housing; and
(c) a knife drive assembly comprising a rotary assembly configured to actuate the knife from the pre-fired position toward the fired position, wherein the rotary assembly comprises:
(i) an input assembly,
(ii) a rotary assembly comprising a compound gear assembly comprising an input pinion, and output pinion, and a rotary pin comprising an angular locking body configured to rotate the input pinion and the output pinion unitarily, and
(iii) an output assembly, wherein the input assembly is configured to travel a first proximal distance in order to rotate the rotary assembly, wherein the rotary assembly is configured to rotate in response to travel of the input assembly along the first proximal distance to drive the output assembly a first distal distance to thereby actuate the knife from the pre-fired position toward the fired position, wherein the first distal distance is greater than the first proximal distance.