Biostimulator Docking Cap Bearing Retention Without Dissimilar-Metal Welds
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Solution Overview
Problem
Existing transport systems for leadless cardiac pacemakers face mechanical failure and corrosion issues due to welds between dissimilar materials in the bearing and docking cap components, which can lead to mechanical weakness and erosion.
Innovation Solution
A weldless bearing retainer mechanism is introduced, using annular retainers on the bearing housing and docking cap to securely hold a bearing in place without direct attachment, allowing for robust mechanical support and reduced corrosion risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welds are used to secure the bearing to the docking cap, then the bearing is mechanically secured, but the system becomes susceptible to corrosion and mechanical weakness due to dissimilar materials
Solution Approach 1:
A bearing retainer acts as an intermediary component between the bearing and the docking cap, eliminating direct contact between dissimilar materials. The retainer is secured to the docking cap via a groove and interference fit, while the bearing is retained by the retainer through radial and axial forces, preventing corrosion at material interfaces while maintaining mechanical strength
Solution Approach 2:
The bearing retention system is divided into separate functional components: the bearing retainer (secured to docking cap), the bearing itself, and the docking cap. This segmentation allows each component to be optimized for its specific function and material properties, with the retainer serving as a dedicated interface element that prevents corrosion between dissimilar materials
2Strength
If welds are used to secure the bearing to the docking cap, then the bearing is mechanically secured, but the system becomes susceptible to mechanical failure due to material incompatibility
Solution Approach 1:
The bearing retainer serves as a mediator that eliminates direct welding between dissimilar materials (bearing and docking cap). The retainer is secured to the docking cap through a groove and interference fit, while the bearing is retained by the retainer through radial and axial forces, preventing corrosion at material interfaces while maintaining mechanical strength
Solution Approach 2:
The welding process is replaced with a mechanical retention system consisting of a groove, interference fit, and bearing retainer forces. This substitution eliminates the need for thermal processes that create vulnerable material transitions, using purely mechanical means to achieve secure bearing attachment without material incompatibility issues
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
The weldless bearing retainer mechanism enhances the mechanical robustness and corrosion resistance of the biostimulator transport system, reducing the likelihood of mechanical failure and improving the reliability of leadless cardiac pacemaker delivery and retrieval processes.
Implementation Method 1
A bearing is radially between the bearing and the docking cap to support such rotation. For example, an outer wall of the bearing, e.g., of an outer ball bearing race, can appose the bearing housing, and an inner wall of the bearing, e.g., of an inner ball bearing race, can appose the docking cap.
Data Source
AI summary
A transport system for delivery or retrieval of a biostimulator, such as a leadless cardiac pacemaker, is described. The biostimulator transport system includes a docking cap supported by a bearing within a bearing housing. The bearing allows relative rotation between a torque shaft connected to the docking cap and an outer catheter connected to the bearing housing. The bearing housing and the docking cap include respective bearing retainers that constrain the bearing within the bearing housing without a weld attachment. The weldless retainers of the biostimulator transport system provide a robust mechanical securement of the bearing that is not vulnerable to corrosion. Other embodiments are also described and claimed.