Surgical instrument with end effector assembly
View Patent ↗An endoscopic instrument includes an elongate hollow member, an actuator that moves axially through the hollow member, and first and second end effectors with respective tissue engaging edges. At least one of the end effectors is rotatably coupled to the hollow member adjacent its distal end. At least one of the end effectors includes a base supporting a resilient leaf-spring portion that includes a respective cutting edge. The resilient leaf-spring portion extends from the base in a cantilevered arrangement and generates a spring force acting on the respective cutting edge such that in a loaded state there is an automatic preload force imparted between the cutting edges of the end effectors to maintain a consistent and continuous mating force between the two opposed tissue engaging edges preferably over the complete range of rotational movement of the end effectors.
1. An end effector assembly, comprising:
a first end effector including a first feature with a first tissue engaging edge; and
a second end effector coupled relative to said first end effector such that said first and second end effectors are moved relative to each other between open and closed positions,
said second end effector including,
a longitudinally extending rigid supporting base having a midline and a longitudinally extending lateral side offset relative to said midline, and
a resilient leaf-spring substantially thinner than said base and having a portion with a deflectable second tissue engaging edge that extends along a length of said portion of said leaf-spring, said portion of said leaf-spring extending from said lateral side of said base in a laterally cantilevered arrangement such that said portion of said leaf-spring is laterally offset from said midline of said base,
wherein as said at least one of said first and second end effectors is moved relative to the other between open and closed positions,
(i) said first and second tissue engaging edges are brought into contact with each other at a contact point, said contact point moving along said length of said portion of said leaf spring portion as said first and second end effectors are moved relative to each other, and said second tissue engaging edge resiliently deflects against said first tissue engaging edge at said contact point,
(ii) said portion of said leaf-spring extends from said base at both a relief angle and a longitudinal angle relative to a rotational plane through which said base moves, such that said portion of said leaf spring generates a lateral spring force in a direction transverse to a plane through which one of said first and second end effectors is moved relative to the other when said first and second end effectors are moved relative to each other between said open and closed positions and against said first feature of said first end effector, and
(iii) said portion of said leaf-spring is flat when not subject to deflection.
2. The end effector assembly of claim 1 , wherein:
said first and second tissue engaging edges are first and second tissue engaging edges.
3. The end effector assembly of claim 1 , wherein:
said leaf-spring portion is formed discrete from said base and coupled to said base along said length of said base.
4. The end effector assembly of claim 3 , wherein:
said leaf-spring portion is welded to said lateral side of said base.
5. The end effector assembly of claim 1 , wherein:
said first end effector includes a longitudinally extending rigid supporting base and an immediately laterally adjacent resilient, leaf-spring portion substantially thinner than said base, said leaf-spring portion forming said first feature, and said first tissue engaging edge being deflectable, said leaf-spring portion extending laterally from said base of said first end effector in a laterally cantilevered arrangement along a length of said base, and longitudinally coextending with said base,
wherein said first and second tissue engaging edges of said first and second end effectors resiliently deflect about each other at said contact point.
6. The end effector assembly of claim 1 , wherein:
said spring force being laterally generated maintains an unchanging and continuous mating force between said first and second tissue engaging edges as said at least one of said first and second end effectors is moved relative to the other between said open and closed positions.
7. The end effector assembly of claim 1 , wherein:
said second tissue engaging edge has a length less than 50 mm.
8. The end effector assembly of claim 1 , wherein:
said resilient leaf-spring portion has a thickness between 0.05 mm and 0.5 mm.
9. The end effector assembly of claim 1 , wherein:
said resilient leaf-spring portion has a tapered profile along its lengthwise dimension.
10. The end effector assembly of claim 1 , wherein:
said resilient leaf-spring portion extends from said base at a relief angle relative to a plane through which said base of said second end effector moves when said at least one of said end effectors is moved relative to the other of said end effectors between said open and closed positions.
11. The end effector assembly of claim 1 , wherein:
at least one of said first and second end effectors are rotatable relative to one another about a pivot axis by axial movement of said actuator, and
said flat leaf-spring portion extends in a plane transverse to both said pivot axis and a longitudinal axis through said end effector.
12. The end effector assembly of claim 1 , wherein:
at least one of said first and second end effectors is rotatably coupled on a pivot axle, and said at least one of said first and second end effectors includes a slot, a cam is coupled to a distal end of said actuator, and said cam is positioned in said slot, such that axial movement of said actuator causes said cam to ride in said slot and effects rotation of said at least one of said first and second end effectors about said pivot axle.
13. A surgical instrument, comprising:
a) said end effector assembly according to claim 1 ;
b) an elongate hollow member having a proximal end and a distal end, said end effector assembly coupled adjacent said distal end of said hollow member; and
c) an actuator coupled to at least one of said first and second end effectors, wherein as said actuator is axially displaced relative to said hollow member, at least one of said first and second end effectors is moved relative to the other in response to said axial displacement of said actuator.
14. The surgical instrument of claim 13 , wherein:
said elongate hollow member is flexible and sized for insertion through an endoscope.
15. An end effector assembly, comprising:
a first end effector including a first feature with a first tissue engaging edge; and
a second end effector including a longitudinally extending rigid supporting base and a laterally offset, resilient leaf-spring portion substantially thinner than said base,
said leaf-spring portion extending from and immediately adjacent a lateral side of said base in a laterally cantilevered arrangement along a length of said base, and longitudinally extending with said base,
said leaf-spring portion having a second tissue engaging edge that extends along a length of said leaf-spring portion,
said first and second end effectors coupled together such that said first and second end effectors are moved relative to each other between said open and closed positions, and
said leaf spring portion extending from and immediately adjacent to said base at a bias angle relative to said base and transverse to a plane through which one of said first and second end effectors is movable relative to the other when said first and second end effectors are moved relative to each other between said open and closed positions to generate a lateral mating force between said first and second tissue engaging edges at a contact point.
16. The end effector assembly according to claim 15 , wherein:
said first and second tissue engaging edges are first and second tissue cutting edges.
17. The end effector assembly according to claim 15 , wherein:
said leaf-spring portion is formed discrete from said base and is coupled to said base along said length of said base.
18. The end effector assembly according to claim 17 , wherein:
said leaf-spring portion is welded to said base.
19. The end effector assembly according to claim 15 , wherein:
said first end effector includes a longitudinally extending rigid supporting base, and said first feature is a resilient leaf-spring portion substantially thinner than said base, said leaf-spring portion of said first end effector extending from a lateral side of said base of said first end effector in a laterally cantilevered arrangement along a length of said base of said first end effector.
20. The end effector assembly according to claim 15 , wherein:
said first and second end effectors are rotatably coupled relative to each other.
21. A surgical instrument, comprising:
a) said end effector assembly according to claim 15 ;
b) an elongate hollow member having a proximal end and a distal end, said end effector assembly coupled adjacent said distal end of said hollow member; and
c) an actuator coupled to at least one of said first and second end effectors, wherein as said actuator is axially displaced relative to said hollow member, at least one of said first and second end effectors is moved relative to the other in response to said axial displacement of said actuator.
22. The surgical instrument of claim 21 , wherein:
said elongate hollow member is flexible and sized for insertion through an endoscope.