Push-Pull Assembly for Medical Catheter Wire Buckling
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Solution Overview
Problem
Existing bendable medical devices and continuum robots face challenges in preventing buckling of small diameter drive wires due to space constraints and limited support, which affects their operational efficiency and durability.
Innovation Solution
A push-pull assembly is introduced, comprising a pusher hypotube, a support sleeve, and a driving wire, where the driving wire is surrounded and supported by the support sleeve and pusher hypotube, reducing the risk of buckling and enhancing operational stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If small diameter drive wires are used to meet space constraints, then the device can be inserted into narrow anatomical spaces, but the drive wires are prone to buckling and lack operational stability
Solution Approach 1:
The drive wire is nested within the support sleeve, which provides continuous external support along the length of the wire. This nested configuration allows the wire to maintain its small diameter while gaining buckling resistance from the surrounding sleeve structure, directly resolving the contradiction between small size and stability.
Solution Approach 2:
The support sleeve acts as an intermediary element between the drive wire and the surrounding environment. It transfers and distributes the forces applied to the wire, preventing localized buckling while allowing the wire to remain small in diameter. The sleeve mediates between the need for small wire size and the need for buckling resistance.
2Reliability
If continuous support structure is added around drive wires to prevent buckling, then wire stability improves, but device complexity and number of parts increases
Solution Approach 1:
The support sleeve serves multiple functions simultaneously: it provides continuous buckling support for the drive wire, acts as a guide for wire insertion and removal, and serves as a structural element that can be integrated with the catheter body. This multi-functionality reduces the need for separate dedicated support components, thereby reducing overall device complexity.
Solution Approach 2:
The support sleeve is merged with the catheter structure, where the sleeve becomes an integral part of the catheter wall or is permanently attached to it. This merging eliminates the need for separate removable support components and simplifies the overall device architecture while maintaining continuous support for the drive wire.
3Reliability
If multiple support components are used to prevent wire buckling, then wire stability improves, but manufacturing cost and assembly complexity increases
Solution Approach 1:
The support structure is segmented into discrete sections along the length of the drive wire, with support sleeves positioned at specific intervals rather than continuous support throughout. This segmentation reduces the total amount of support material needed and simplifies manufacturing, while still providing adequate buckling prevention at critical locations.
Solution Approach 2:
The support sleeves are pre-formed and pre-positioned within the catheter structure before final assembly. This preliminary action allows for precise positioning and alignment to be built into the manufacturing process itself, eliminating the need for complex post-assembly adjustments and reducing assembly steps.
Data Source
AI summary
Disclosed are a robotic apparatus, a catheter and method for use, with a push-pull assembly that includes a pusher hypotube with a distal end extending towards the continuum robot, a proximal end extending towards the controller, and a hollow extending through at least a part of a longitudinal length thereof; a support sleeve with a proximal end slidably maintained within the hollow; and a driving wire with a proximal end affixed to the pusher hypotube and a portion extending through the support sleeve. A deformable member may be positioned within a portion of the hollow that surrounds at least a portion of the driving wire, with the deformable member maintaining at least one of a uniform inner diameter and/or a uniform outer diameter when compressed. The deformable member may be formed of metal with a predetermined pattern that surrounds at least at part of the hub hypotube.