Reinforced Steerable Sheath Coupling Displacement
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Solution Overview
Problem
Existing steerable sheath assemblies fail at the point of contact between the pull wires and the sheath due to weakness in the shaft section where the pull wires are connected, leading to displacement and failure upon high deflection or repeated actuation.
Innovation Solution
A reinforced steerable sheath assembly is designed with a means to prevent displacement of the coupling, featuring a reinforcement section that reinforces the area of the shaft where the pull wires are coupled, maintaining the angle between the pull wire and the coupling at approximately 90 degrees during actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pull wire coupling is used to connect pull wires to the sheath, then the sheath can be deflected by actuating the pull wires, but the coupling point becomes weak and fails under high deflection or repeated actuation
Solution Approach 1:
The patent applies local quality by creating a reinforcement section with different material properties than the rest of the sheath. This reinforcement section has higher structural strength and rigidity specifically at the coupling point where pull wires connect to the sheath, while the rest of the sheath maintains its flexibility for deflection. The reinforcement section is formed with a durometer value higher than the deflectable section, providing localized strength enhancement without compromising overall sheath flexibility.
2Adaptability or versatility
If the sheath is made flexible to allow deflection, then the sheath can be steered, but the shaft section at the coupling point becomes weak and displaces under stress
Solution Approach 1:
The patent implements local quality by creating a reinforcement section with distinct material properties positioned specifically at the coupling point. This reinforcement section has increased rigidity and strength compared to the flexible deflectable section, preventing displacement and pivoting of the pull wire coupling while allowing the rest of the sheath to remain flexible for steering operations.
Solution Approach 2:
The patent employs composite materials by combining sections of sheath with different durometer values and material properties. The reinforcement section uses a harder, more rigid material (higher durometer) to provide structural support at the coupling point, while the deflectable section uses a softer, more flexible material (lower durometer) to enable bending and steering. This composite construction allows the sheath to simultaneously achieve flexibility for deflection and strength at critical coupling points.
Data Source
Figure 1A~1B
Figure 1C
Figure 1D~1F
AI summary
A method and apparatus are disclosed for a reinforced steerable sheath assembly that is usable with an actuator comprising a shaft section defining a sheath that is operable to be deflected, and one or more pull wires that are coupled to the sheath via a coupling at a point of contact between the pull wires and the sheath. The pull wires being operable to be coupled to the actuator for actuating the pull wires. The reinforced steerable sheath assembly further comprises a means for preventing displacement of the coupling, wherein the means for preventing displacement to minimize failure at the coupling at the point of contact between the pull wires and the sheath upon actuation of the pull wires upon actuation of the actuator to deflect the sheath.