Radial Compression Mechanism With Constant Die Gap
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Solution Overview
Problem
Existing radial compression mechanisms for medical devices like stents and catheters suffer from inconsistent die-to-die gaps and inaccuracies in maintaining a round cavity shape, leading to potential damage and inadequate compression.
Innovation Solution
A radial compression mechanism featuring pivotally mounted dies with elongated arcuate bodies and inwardly spiraling orientation, where the working tips define a central cavity with a constant gap between sliding and convex surfaces, allowing for uniform rotation and maintaining a consistent gap during open and closed orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wedge-shaped dies with planar surfaces are arranged to form a cylindrical cavity with hinges, then the mechanism can change cavity diameter, but the gap between adjacent wedges varies with diameter causing device damage
Solution Approach 1:
The patent applies curvature by replacing the planar surfaces of traditional wedge-shaped dies with arcuate (curved) surfaces. Each die has an elongated arcuate body with a concave sliding surface and a convex working surface. This curvature allows the dies to maintain a constant gap between adjacent dies throughout the compression stroke, eliminating the varying gap problem that causes device damage while still achieving the required cavity diameter adjustment.
2Object-affected harmful factors
If linear guides are used to drive wedges in unison, then the gap between wedges can be constant, but the positional relationship of wedge ends becomes inaccurate reducing cavity roundness
Solution Approach 1:
The patent divides the compression system into multiple independent arcuate dies, each mounted on its own pivot pin attached to a hinge plate. This segmentation allows each die to be precisely positioned and controlled independently through the pivot mechanism, ensuring accurate positional relationships between adjacent dies. The pivot-based mounting provides inherent mechanical guidance that maintains cavity roundness better than linear guides while preserving constant gap geometry.
Solution Approach 2:
The arcuate shape of each die body, with its concave sliding surface and convex working surface, inherently guides the motion and positioning of adjacent dies. The curved geometry ensures that as dies rotate about their pivot points, they maintain precise positional relationships and constant spacing, achieving both gap consistency and cavity roundness simultaneously.
3Object-affected harmful factors
If more dies are added to reduce maximum gap, then the mechanism size increases, but compactness is reduced
Solution Approach 1:
The arcuate geometry of the dies creates a natural constant gap between adjacent dies throughout the compression stroke, regardless of the number of dies used. This curved surface design eliminates the need to increase the number of dies to reduce maximum gap, as the gap remains constant with just 6-8 properly configured arcuate dies. The mechanism maintains a compact size while achieving the desired gap control.
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 solution ensures consistent and accurate compression with a constant gap, reducing the risk of damage and improving the roundness of the compressed device, addressing the limitations of prior art mechanisms.
Implementation Method 1
mechanisms are used to radially compress cylindrical devices such as stents, balloons, and catheters
Implementation Method 2
compressing the stent radially inward onto the balloon with enough pressure to permanently deform the stent
Implementation Method 3
The dies are mounted on the hinge plate in an inwardly spiraling orientation with the outer ends positioned in a circle and the working tips cooperating to define a central product-receiving cylindrically-shaped cavity
Implementation Method 4
each having an elongated arcuate body with an outer end pivotally attached to a hinge plate
Data Source
AI summary
Radial compression mechanism includes a plurality of dies each having an elongated arcuate body with an outer end pivotally attached to a hinge plate and an inner working tip. The dies are mounted on the hinge plate in an inwardly spiraling orientation with the outer ends positioned in a circle and the working tips cooperating to define a central product-receiving cylindrically-shaped cavity. The product-receiving cavity is transitional between an open and a closed orientation. The working tip of each die has a sliding surface and a working surface with the sliding surface positioned in parallel juxtaposition to the working surface of an adjacent die and a constant width gap therebetween. Driving mechanism is coupled to rotatably drive all of the dies in unison to transition between open and closed orientations. The width of the gap remains constant during transition and between the open and closed orientations.