Radial Compression Dies for Incremental Stent Loading
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Solution Overview
Problem
Current radial compression mechanisms for stents are cumbersome, requiring longer lengths that are difficult to manufacture accurately, prone to compliance issues, and necessitate high force requirements, often using low-friction plastics that suffer from wear and contamination risks.
Innovation Solution
A radial compression mechanism with a shorter length, using a plurality of compression dies arranged radially to form a cylindrical cavity, decoupling the stent length from the compression mechanism, allowing for incremental compression and indexing, and utilizing durable materials with a reduced sliding action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the radial compression mechanism is made longer to accommodate longer stents, then the stent length can be matched, but the manufacturing precision and accuracy of the mechanism deteriorate
Solution Approach 1:
The compression mechanism is divided into multiple stationary compression stations arranged in series along the stent length. Each station compresses a segment of the stent independently, allowing the overall mechanism to handle long stents while each individual station maintains compact dimensions and high manufacturing precision.
Solution Approach 2:
The problem is solved by transitioning from a single long linear compression path to a distributed array of compression stations. The compression action is distributed across multiple locations along the stent length, effectively using the longitudinal dimension to accommodate long stents while keeping each compression station compact and precise.
2Length of moving object
If the radial compression mechanism is made longer to accommodate longer stents, then the stent length can be matched, but the compliance and stability of the mechanism worsen
Solution Approach 1:
The long compression mechanism is segmented into multiple independent stationary stations, each with its own support structure. This segmentation allows each station to be independently supported and stabilized, preventing the compliance issues that would occur in a single long continuous mechanism.
Solution Approach 2:
Multiple stationary compression stations act as intermediaries between the stent and the compression force. Each station is independently supported by the device structure, providing stable compression points distributed along the stent length rather than relying on a single long compliant structure.
3Length of moving object
If the radial compression mechanism is made longer to accommodate longer stents, then the stent length can be matched, but the force requirement and operational complexity worsen
Solution Approach 1:
The total compression force requirement is segmented and distributed across multiple independent compression stations. Each station applies compression force to a local segment of the stent, reducing the force requirement at any single location compared to compressing the entire stent length in one mechanism.
4Ease of operation
If low-friction plastic materials are used for the compression dies, then the stent can slide through easily, but the wear and contamination risk increases
Solution Approach 1:
The mechanical sliding contact between stent and compression die is replaced with a different mechanism. The stent is compressed radially while being advanced through the stationary stations, eliminating the need for the stent to slide axially through the compression dies. This substitution eliminates the wear and contamination problems associated with sliding contact.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach results in a more accurate, cost-effective, and less force-intensive compression process, reducing manufacturing complexity and wear-related issues while maintaining stent accuracy and cleanliness.
Implementation Method 1
a plurality of compression dies arranged radially to form a cylindrical cavity for radially compressing stents and other devices
Implementation Method 2
US20030386747 discloses a method of manufacturing a medical device such as stents and stent-grafts comprising reducing the size of the medical device and vibrating the device
Data Source
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AI summary
A radial compression mechanism incorporates an introduction funnel that truncates down to a cylindrical cavity for radial compressing articles. The introduction funnel facilities the loading of an article into the cylindrical cavity and enables incremental radial compression of articles, such as stents. The radial compression mechanism employs a plurality of compression dies that are configured radially about the cylindrical cavity and move in unison to cause the cylindrical cavity to open or close. The compression dies are coupled with a base and drive mechanism for moving them in unison. A method of loading a delivery catheter with a radially compressed article, such as a stent, includes positioning a delivery catheter over a compressed portion of an article that extends from an exit end of tile cylindrical catheter. One or more drive mechanism may be used to automatically and incrementally load a compressed article into a delivery catheter.