Melt-Bonded Joint for Medical Device Sheaths
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Solution Overview
Problem
Existing medical device delivery systems face challenges in efficiently joining sheaths and guide channel members, particularly in rapid insertion systems, due to the use of adhesives and subassemblies that are time-consuming, prone to joint failure, and lack uniform stress distribution and flexibility.
Innovation Solution
A melt-bonded joint is developed to couple the outer sheath distal end and outer guide channel member second end using a thermal mechanical bond that cures quickly and uniformly, providing consistent flexibility and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If adhesives and subassemblies are used to join sheaths and guide channel members, then the joint can be formed, but the processing time increases and the joint is prone to failure
Solution Approach 1:
The patent replaces adhesive bonding (chemical system) with heat sealing (thermal system). The heat sealable layer is heated to melt and bond the sheath components together, eliminating the need for adhesives and subassemblies. This thermal mechanical bonding process reduces processing time and improves joint reliability by creating a uniform, controlled bond without the variability inherent in adhesive application and curing.
Solution Approach 2:
The patent changes the bonding mechanism from chemical adhesion to thermal fusion by controlling temperature parameters. The heat sealable layer undergoes phase change from solid to molten state during bonding, then solidifies to form a strong joint. This parameter-based control (temperature, time, pressure) provides consistent, reliable bonding without the time-consuming steps of adhesive application and curing.
2Strength
If adhesives and subassemblies are used to join sheaths and guide channel members, then the joint can be formed, but the stress distribution becomes non-uniform
Solution Approach 1:
The patent replaces adhesive bonding with heat sealing, which provides more uniform stress distribution. The heat sealable layer melts uniformly across the bonding interface and solidifies to create consistent bonding strength throughout the joint, eliminating the non-uniform stress distribution characteristic of adhesive bonds where stress concentrates at adhesive edges and interfaces.
Solution Approach 2:
The patent applies heat sealing locally at the bonding interface where the heat sealable layer is positioned between sheath components. This localized thermal bonding creates uniform stress distribution precisely where needed, while maintaining the flexibility and structural integrity of the overall assembly. The heat sealable layer acts as a localized bonding zone with controlled material properties optimized for uniform stress distribution.
3Adaptability or versatility
If adhesives and subassemblies are used to join sheaths and guide channel members, then the joint can be formed, but the flexibility and adaptability are reduced
Solution Approach 1:
The patent replaces complex adhesive bonding systems with simpler heat sealing. The heat sealable layer integrates directly into the sheath structure, eliminating separate adhesive components and subassemblies. This reduces device complexity while maintaining or improving flexibility, as the heat-sealed joint can be designed to match the flexibility characteristics of the adjacent sheath portions.
Solution Approach 2:
The patent merges the bonding function into the sheath structure itself through the heat sealable layer, rather than using separate adhesive components and subassemblies. This integration reduces the number of parts and assembly steps, simplifying the overall device while maintaining flexibility. The heat sealable layer becomes an inherent part of the sheath design, providing both structural continuity and flexibility.
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 melt-bonded joint enhances the assembly process by reducing processing time, improving joint strength, and ensuring uniform flexibility, thereby facilitating the deployment of self-expanding stents and other implantable prostheses within the body.
Implementation Method 1
A first sheath having an inner layer with a passageway extending longitudinally therethrough, a coil positioned longitudinally around at least a portion of the inner layer, and an outer layer disposed about the coil and being melt bonded to the inner layer through coil spacings
Implementation Method 2
an outer layer disposed about the coil and being melt bonded to the inner layer through coil spacings
Data Source
AI summary
Joint assemblies for joining sheaths for use in medical devices are provided, as are methods of manufacturing the joint assemblies. An elongate first sheath has a distal end portion having melt bonding material. A second sheath has first and second end portions, the second end portion having melt bonding material. An outer sleeve body includes proximal and distal engaging portions that have melt bonding materials. The proximal engaging portion is disposed about and melt bonded to the first sheath distal end portion. The distal engaging portion is disposed about and melt bonded to the second sheath proximal end portion. In one embodiment, one or both sheaths have an inner layer, a coiled middle layer optionally stopping short of the joint assembly, and an outer layer that has said melt bonding materials. In one embodiment, the sheaths are used in a rapid insertion catheter delivery system.