Curved Guide Member for Articulating Surgical Instruments
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Solution Overview
Problem
Existing surgical instruments with articulating portions face limitations in the degree of articulation due to over-bending and over-stressing of drive members, which can lead to buckling and bulging, especially when the articulation joint is bent, restricting the tool's ability to be fully articulated.
Innovation Solution
A loading unit with a curved guide member that distributes the bending of the drive member over three points, including the proximal and distal ends of the guide member, allowing for greater articulation without over-bending, and an offset pivot point to minimize drive member travel during articulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a straight guide member is used to direct the drive member through the articulation joint, then the structure is simple, but the degree of articulation is limited and the drive member becomes over-bent and over-stressed
Solution Approach 1:
The patent applies curvature by replacing the straight guide member with a curved guide member that has a specific arc shape. This curved configuration allows the drive member to follow a more gradual bending path through the articulation joint, distributing the bend over three points (proximal end, midpoint, and distal end of the curve) rather than concentrating stress at two points. This resolves the contradiction by enabling greater articulation angles while preventing over-bending and over-stressing of the drive member.
2Adaptability or versatility
If the articulation joint is bent to increase articulation range, then the tool assembly can reach more positions, but the drive member buckles and bulges
Solution Approach 1:
The curved guide member with its arc-shaped configuration distributes the bending stress of the drive member over three points along its length, preventing concentration of stress that would cause buckling and bulging. This allows the articulation joint to achieve greater ranges of motion while maintaining drive member integrity.
Solution Approach 2:
The patent introduces an additional dimensional consideration by positioning the pivot point offset from the longitudinal axis of the drive member. This offset positioning in a different spatial dimension allows the drive member to articulate through a larger angle without the distal end exceeding safe bending limits, thereby preventing buckling while expanding articulation range.
3Strength
If the drive member is made more rigid to prevent buckling, then structural integrity is improved, but the ability to articulate is reduced
Solution Approach 1:
The curved guide member allows a relatively rigid drive member to articulate smoothly by providing a pre-formed bending path. The curvature distributes stress over three points, enabling the rigid drive member to achieve significant articulation angles without buckling, thus resolving the contradiction between rigidity and articulation capability.
Data Source
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AI summary
A loading unit is provided. The loading unit includes a housing defining a longitudinal axis, a mounting support pivotally connected to the housing and including a tool assembly operably connected thereto, a curved guide member extending between the housing and the support member, and a drive member extending through the curved guide member for actuating the tool assembly when the mounting support is articulated relative to the housing.