Shape-Memory Alloy Guide Tube for Laser Surgery Handpiece
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Solution Overview
Problem
Handpieces for manipulating optical fibers during laser surgical procedures face challenges in easy sterilization, adaptable fiber length, spatial positioning, and compatibility with MRI imaging, while existing solutions do not adequately address these requirements for repeated use and cleaning processes.
Innovation Solution
A handpiece with a guide tube made from a shape-memory alloy with a transition temperature between 50 °C and 120 °C, allowing for plastic deformation at room temperature for desired shapes and reverting to a straight shape upon heating, facilitating easy cleaning and sterilization, combined with a cooling liquid supply and elastic seals for secure fiber handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the guide tube is made from a shape-memory alloy to allow plastic deformation for desired shapes, then adaptability to different spatial positions is improved, but the guide tube may deform or change shape during sterilization processes
Solution Approach 1:
The patent applies parameter changes by utilizing the phase transition temperature of the shape-memory alloy as a critical threshold. During normal operation and sterilization (below transition temperature), the alloy maintains its martensitic phase with high plastic deformability for shaping. During autoclave sterilization (above transition temperature), it transforms to austenitic phase where it becomes rigid and dimensionally stable, preventing unwanted deformation while maintaining adaptability for positioning.
Solution Approach 2:
The patent employs phase transitions of the shape-memory alloy between martensitic and austenitic phases to resolve the contradiction. The martensitic phase (at operating temperatures) allows easy plastic deformation for adapting to different spatial positions, while the austenitic phase (at sterilization temperatures) provides dimensional stability and rigidity, preventing deformation during sterilization processes.
2Reliability
If the guide tube is made rigid to ensure dimensional stability during sterilization, then sterilization reliability is improved, but the ability to adapt to different spatial positions and perform plastic deformation is reduced
Solution Approach 1:
The patent uses parameter changes by exploiting the temperature-dependent properties of the shape-memory alloy. At sterilization temperatures above the transition point, the alloy exhibits austenitic phase characteristics with high rigidity and dimensional stability, ensuring reliable sterilization. At operating temperatures below the transition point, it transforms to martensitic phase, becoming soft and highly adaptable for plastic deformation and spatial positioning.
Solution Approach 2:
The patent applies dynamics by making the guide tube's mechanical properties dynamic rather than static. The shape-memory alloy automatically adjusts its rigidity and deformability based on temperature conditions, providing the right balance of properties at different stages: rigid during sterilization for reliability, and flexible during operation for adaptability.
3Ease of operation
If the guide tube is made from plastic material to be flexible and adaptable, then ease of manipulation is improved, but sterilization becomes difficult and reliability is reduced
Solution Approach 1:
The patent employs composite materials by using a shape-memory alloy (such as nitinol) that combines properties of both metals and polymers. It exhibits metal-like strength and sterilization resistance while displaying polymer-like flexibility and adaptability when in the martensitic phase, thus resolving the contradiction between ease of manipulation and sterilization capability.
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
Ensures dimensional stability and rigidity during use, allows for desired fiber alignment, easy cleaning, and indicates successful sterilization by shape change, while maintaining safety and compatibility with MRI environments.
Implementation Method 1
The guide tube (9) is formed from a shape memory alloy, in particular from a nitinol alloy
Implementation Method 2
a cooling liquid supply which supplies a cooling liquid to the guide tube
Data Source
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AI summary
A handpiece (1) for handling an optical fiber during laser surgery comprises a handle body (2) extending along a main axis (10), a guide tube (9) attached to one end of the handle body (2), wherein a lumen of the guide tube (9) is aligned with a through-hole (6) extending along the main axis (10) through the handle body (2), and a holding device arranged in the handle body (2) in the region of the through-hole (6) for the optical fiber extending through the through-hole (6) and the lumen of the guide tube (9). The guide tube (9) is made of a shape-memory alloy that has a transition temperature between 50 °C and 120 °C. The guide tube (9) has a straight basic shape, which it returns to after plastic deformation below the transition temperature when the transition temperature is exceeded.