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Publication Number
US-8128649-B2
Publication Date
2012-03-06
Expiration Date
Abstract
An endoscopic scissor instrument includes an elongate hollow member, an actuator that moves axially through the hollow member, and first and second scissor blades with respective cutting surfaces. At least one of the scissor blades is rotatably coupled to the hollow member adjacent its distal end. At least one of the scissor blades 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 scissor blades to maintain a consistent and continuous mating force between the two opposed sharpened cutting edges preferably over the complete range of rotational movement of the scissor blades.
Core Innovation
An elongate hollow member includes a proximal end and a distal end, and an axial actuator moves axially through the hollow member and is coupled to at least one of first and second scissor blades rotatably coupled adjacent the distal end. The axial actuator provides rotational movement of at least one scissor blade relative to the other in response to the axial movement to rotate the scissors blades between open and closed positions.
At least one scissors blade includes a cutting edge feature, where the first scissors blade includes a first feature with a first cutting edge. The second scissors blade includes a longitudinally extending rigid supporting base having a midline and a longitudinally extending lateral side offset relative to the midline, and a resilient leaf-spring portion substantially thinner than the base extends immediately adjacent the base in a cantilevered arrangement from the lateral side.
The leaf-spring portion is laterally offset from the midline, extends at a bias angle relative to the base, and has a deflectable second cutting edge extending along a length of the leaf-spring portion. As the blades rotate relative to one another between open and closed positions, the first and second cutting edges are brought into contact at a contact point that moves along the length of the leaf-spring portion, and the second cutting edge resiliently deflects against the first cutting edge at the contact point.
The bias angle generates a lateral spring force transverse to a plane through which one blade is rotated relative to the other, maintaining continuous edge-to-edge mating and consistent cutting contact throughout the full blade rotation range while addressing prior-art bowed blades and biasing cams requiring tight tolerances.
Claims Coverage
The document provides two independent claims that focus on an elongate hollow member with an axial actuator driving rotation of opposed scissor blades, and on a resilient, cantilevered, bias-angle leaf-spring cutting feature that maintains cutting-edge engagement as the blades move between open and closed positions. Across the independent claims, the coverage emphasizes the structural relationship between a rigid supporting base and a laterally offset resilient leaf-spring portion, including contact-point movement and lateral mating or spring-force generation.
Axial-actuated rotational scissors with elongate hollow member
The instrument includes an elongate hollow member having a proximal end and a distal end, and an actuator that moves axially through the hollow member. First and second scissor blades are rotatably coupled adjacent the distal end, and the actuator is coupled to at least one of the blades to provide rotational movement of at least one blade relative to the other in response to axial movement so as to rotate the blades between open and closed positions.
Cantilevered laterally offset leaf-spring cutting edge on rigid base
The first scissors blade includes a first cutting edge, and the second scissors blade includes a longitudinally extending rigid supporting base with a midline and a longitudinally extending lateral side offset relative to the midline. A resilient leaf-spring portion substantially thinner than the base is adjacent the base, extends from the lateral side in a cantilevered arrangement and laterally offset from the midline, and extends at a bias angle relative to the base with a second cutting edge extending along a length of the leaf-spring portion.
Contact-point edge engagement maintained by resilient leaf-spring deflection and bias-angle lateral spring force
As the blades are rotated between open and closed positions, the first and second cutting edges are brought into contact at a contact point. The contact point moves along the length of the leaf-spring portion as the blades are rotated, and the second cutting edge resiliently deflects against the first cutting edge at the contact point. The bias angle relative to the base generates a lateral spring force transverse to a plane through which one blade is rotated relative to the other to generate a lateral mating force between the first and second cutting edges at the contact point, and the leaf-spring portion is flat when not subject to deflection.
Leaf-spring portion bias-angle orientation transverse to blade rotation plane to generate lateral mating force
The leaf-spring portion extends from and immediately adjacent the rigid base at a bias angle relative to the base and transverse to a plane through which one of the scissors blades is rotated relative to the other when the blades are moved between open and closed positions. This orientation generates a lateral mating force between the first and second cutting edges at a contact point.
The independent claims are directed to an endoscopic scissor instrument where axial actuation through an elongate hollow member rotates opposed scissor blades, and where the cutting interaction is governed by a cantilevered, laterally offset, bias-angle resilient leaf-spring portion on a rigid supporting base. The claims require contact-point movement along the leaf-spring length and resilient deflection of the leaf-spring cutting edge, with the bias angle producing a lateral spring force/lateral mating force that maintains cutting-edge engagement across the blade rotation range.
Stated Advantages
Maintains continuous edge-to-edge mating and consistent cutting contact throughout the full blade rotation range.
Improves small-blade cutting feel while avoiding prior-art bowed blades and biasing cams requiring tight tolerances.
Documented Applications
No documented applications found
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