Stent Marker Mechanical Locking via Double Conical Cutout

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Solution Overview

Problem

Existing bodily implants, such as stents, face challenges in achieving good X-ray visibility while maintaining simplicity and cost-effectiveness in manufacturing, and ensuring safe insertion into bodily channels without causing injury.

Innovation Solution

A bodily implant with a marker element made of X-ray visible material is inserted into a cutout with conical expansions on both sides, forming a double cone shape, which is securely fastened using pressing or riveting, allowing for high mechanical locking and flush integration with the implant structure, eliminating transitional edges that could cause injury.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If a marker element is inserted into a cutout in the implant structure, then X-ray visibility is improved, but the manufacturing precision and secure fastening become challenging

Engineering Contradiction:

ImproveX-ray visibilityVSAvoidmarker element fastening precision

Core Design Contradiction:

Difficulty of detecting and measuringVSManufacturing precision

Solution Approach 1:

The cutout is designed with an asymmetric double conical shape (narrower at one end, wider at the other) rather than a symmetric cylindrical shape. This asymmetric geometry creates a tapered interference fit that guides the marker element into proper alignment and provides mechanical locking through friction, thereby improving fastening precision without requiring extremely tight manufacturing tolerances

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The conical shape changes the geometric parameters of the cutout from a uniform cylinder to a tapered form with varying diameter along its length. This parameter change creates a self-aligning and self-locking mechanism where the marker element is gradually compressed and secured as it is inserted, improving both the ease of insertion and the security of fastening while maintaining manufacturing feasibility

Inventive Principle:

Principle #35Parameter changes

2Strength

If the marker element is securely fastened using pressing or riveting, then mechanical locking is improved, but the device complexity increases

Engineering Contradiction:

Improvemechanical locking strengthVSAvoidfastening process complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The double conical shape of the cutout enables the marker element to self-lock through friction and geometric interference when pressed into place. The tapered geometry automatically creates a locking effect as the marker element is inserted and compressed, eliminating the need for additional riveting steps or complex fastening mechanisms. The structure serves its own fastening function, reducing overall device complexity while maintaining strong mechanical locking

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The functional requirements of the cutout are merged into a single double conical geometric feature that simultaneously provides: (1) guidance for marker element insertion, (2) friction-based mechanical locking, and (3) a flush surface for integration. By combining multiple functions into one structural element, the fastening process is simplified while maintaining strong mechanical attachment

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the marker element is pressed or riveted into the cutout, then the marker element is securely fastened, but manufacturing costs increase

Engineering Contradiction:

Improvemarker element secure fasteningVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The complex multi-step fastening processes (such as riveting with multiple operations, alignment fixtures, and quality control steps) are replaced by a simple pressing operation into the double conical cutout. The geometric shape itself provides the locking mechanism, substituting complex mechanical fastening systems with a simpler geometric interference fit that achieves equivalent or superior reliability at lower cost

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Object-affected harmful factors

If transitional edges are eliminated by flush integration, then safety during insertion is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improveinjury risk during insertionVSAvoidflush integration precision

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The double conical shape creates an asymmetric taper that naturally guides the marker element to a precise flush position with the implant structure. The varying diameter along the cone provides a self-positioning effect where the marker element automatically aligns and seats at the correct depth, achieving flush integration without requiring extremely tight manufacturing tolerances. The asymmetric geometry converts positioning complexity into a self-aligning feature

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS8425589B2Mechanical locking of an X-ray marker in the eyelet of a stent or in another bodily implant

Publication Date: 2013.04.23 ADMEDES SCHUESSLER GMBH

AI summary

A bodily implant, in particular a stent, for insertion or implantation into a living body, having a marker element made of an X-ray visible material which is inserted into a cutout in an implant structure is disclosed. The cutout has expansions on both of its opening sides, and the marker element is pressed or riveted into the cutout so that a positive fit is formed between the marker element and the implant structure.