Overmolded Knife Beam Assembly for High-Load Tissue Cutting
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Solution Overview
Problem
Existing electrosurgical instruments face challenges in providing a robust knife assembly that withstands longitudinal loads without buckling or fracturing, while minimizing component count and manufacturing complexity.
Innovation Solution
A knife assembly design featuring an elongate body overmolded with plastic about a metal knife beam, nested within a closure beam and inner guide, which provides structural support and eliminates the need for welding, thus enhancing robustness and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a robust knife assembly is provided to withstand longitudinal loads without buckling or fracturing, then strength is improved, but device complexity increases
Solution Approach 1:
The patent combines the knife beam and elongate body into a single integrated component. The metal knife beam is overmolded with the elongate body in one manufacturing process, eliminating the need for separate components and welds. This merging maintains structural strength while reducing component count and assembly complexity.
Solution Approach 2:
The patent uses composite construction by overmolding the elongate body material around the metal knife beam. This creates a composite structure that combines the high strength and stiffness of metal with the protective and insulating properties of the overmold material, achieving robust column strength without requiring additional reinforcement components.
2Strength
If welds are used to provide structural strength, then strength is improved, but ease of manufacture deteriorates
Solution Approach 1:
The overmolding process merges the knife beam and elongate body into a single integrated component in one manufacturing step. This eliminates the need for separate welding operations to join discrete parts, significantly simplifying manufacturing while maintaining structural integrity through the composite overmolded structure.
Solution Approach 2:
The patent replaces the mechanical joining method (welding) with a molding process. The elongate body is overmolded directly onto the knife beam, creating a mechanically integrated structure without requiring thermal or mechanical welding operations. This substitution simplifies manufacturing by eliminating complex welding procedures and associated quality control requirements.
Data Source
AI summary
An apparatus includes a body, a shaft assembly, and an end effector. The shaft assembly includes an outer shaft and a knife assembly. The knife assembly includes an elongate body and a beam. At least a portion of the body is slidably positioned within a hollow interior of the outer shaft. The beam extends distally from the distal end of the body. The beam includes a proximal portion positioned within the body and thereby secured to the body. The beam further includes a distal portion having a knife that is operable to sever tissue. The end effector includes a first jaw and a second jaw. The first jaw is movable relative to the second jaw between an open position and a closed position. The knife is operable to translate along one or both of the first jaw or the second jaw.