Stent Delivery System Multi-Pinion Rack Mechanism
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Solution Overview
Problem
Conventional stent delivery systems face challenges in delivering long stents or multiple stents without elongating the grip, leading to reduced tractability during procedures due to the need for a long rack member to accommodate the necessary movement distance.
Innovation Solution
The stent delivery system incorporates a displacement member with multiple driving rotators arranged along its axial direction, allowing continuous movement in the proximal direction without elongating the grip, and an interlocking mechanism to simplify the operation and control the release speed of the stent, enabling efficient positioning and release of stents within the body lumen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a conventional single pinion rack mechanism is used to deliver long stents or multiple stents, then the necessary movement distance is achieved, but the grip length is elongated and tractability deteriorates
Solution Approach 1:
The single pinion is divided into multiple pinions (first pinion and second pinion) arranged along the rack member. Each pinion engages with the rack at different positions, allowing the rack to be moved incrementally through sequential engagement rather than requiring a single long-travel pinion. This segmentation enables the grip to remain compact while achieving the necessary total movement distance for delivering long stents or multiple stents.
Solution Approach 2:
The system transitions from a static single pinion configuration to a dynamic multi-pinion system where pinions can be selectively engaged or disengaged from the rack member. The operation wheels can be rotated to engage different pinions with the rack, creating a dynamic mechanism that adapts to different stent lengths and delivery requirements without requiring a proportionally longer grip.
2Length of stationary object
If multiple pinions are used to achieve the necessary movement distance, then the grip length is shortened, but the operation complexity increases
Solution Approach 1:
Multiple operation wheels are merged into a single integrated operation unit that can control the engagement of multiple pinions with the rack member. The operation wheels are arranged such that they can be operated sequentially or simultaneously through a unified control mechanism, reducing the perceived operational complexity despite the presence of multiple pinions.
Solution Approach 2:
Each pinion is designed with universal functionality to engage with the rack member and produce the same type of movement (proximal displacement of the outer tube). This standardization means that while there are multiple pinions, each performs the same fundamental function, simplifying the operational learning curve and reducing complexity compared to having different types of mechanisms for different segments of the movement.
Data Source
AI summary
A stent delivery system is disclosed in which a stent is contained in a sheath in an initial state and the stent is released inside a living body lumen in accordance with a movement of the sheath in a proximal direction with respect to an inner member. A movement mechanism of the stent delivery system has a rack member which is connected to a proximal end of the sheath, and a plurality of pinions which move the rack member in accordance with rotations thereof.