Ocular Forceps Shaft Hardened S-Phase Layer Deflection Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional medical instruments with extra-narrow metal members suffer from low deflection resistance, leading to difficulty in operation due to slight contact with human tissues causing significant deflection, requiring expert skill for proper use.
Innovation Solution
An ocular forceps with a metal tubular shaft made of austenitic stainless steel or cobalt-chromium-nickel alloy, featuring a hardened S-phase layer formed through nitriding or carburizing, enhancing deflection resistance while maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the shaft is made extra-narrow (thickness ≤1.0mm) to enable use in ocular surgery, then the flexibility and adaptability for surgical access is improved, but the deflection resistance deteriorates causing large deflections upon tissue contact
Solution Approach 1:
The patent applies different material properties to different regions of the shaft. The core maintains the base metal properties for flexibility, while the surface layer is transformed into a hardened phase (martensite, bainite, or sorbite) through induction heating and quenching. This creates a gradient structure where the surface has high deflection resistance while the core retains flexibility, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent creates a composite structure within the shaft by forming a hardened layer on the surface of the metal tubular shaft. The shaft consists of a base metal (austenitic stainless steel, cobalt-chromium-nickel alloy, nickel-chromium alloy, or cobalt-chromium alloy) with a surface layer of transformed phase. This composite structure combines the flexibility of the base metal with the high strength and deflection resistance of the hardened surface layer.
2Strength
If the shaft thickness is increased to improve deflection resistance, then the strength and stability are improved, but the flexibility and ability to navigate narrow ocular pathways deteriorates
Solution Approach 1:
The patent applies different material properties to different regions of the shaft. The core maintains the base metal properties for flexibility, while the surface layer is transformed into a hardened phase (martensite, bainite, or sorbite) through induction heating and quenching. This creates a gradient structure where the surface has high deflection resistance while the core retains flexibility, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent changes the physical and mechanical parameters of the shaft surface through heat treatment. By controlling the induction heating temperature and quenching process, the surface layer transforms into different hardened phases (martensite for maximum hardness, bainite for balanced properties, or sorbite for toughness) while maintaining the original shaft dimensions and flexibility characteristics.
3Strength
If a hardened layer is formed on the shaft surface to improve deflection resistance, then the strength and stability are improved, but the flexibility may be lost if the hardened layer is too thick
Solution Approach 1:
The patent applies different material properties to different regions of the shaft. The core maintains the base metal properties for flexibility, while the surface layer is transformed into a hardened phase (martensite, bainite, or sorbite) through induction heating and quenching. This creates a gradient structure where the surface has high deflection resistance while the core retains flexibility, resolving the contradiction between these two requirements.
Solution Approach 2:
The patent changes the physical and mechanical parameters of the shaft surface through heat treatment. By controlling the induction heating temperature and quenching process, the surface layer transforms into different hardened phases (martensite for maximum hardness, bainite for balanced properties, or sorbite for toughness) while maintaining the original shaft dimensions and flexibility characteristics.
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 ocular forceps exhibit improved deflection resistance and flexibility, preventing large deflections upon contact with human tissues, thus enhancing operability and reducing the risk of cracking.
Implementation Method 1
the shaft has a hardened layer that is comprised of an S-phase formed by nitriding or carburizing
Implementation Method 2
the shaft has a hardened layer that is comprised of an S-phase formed by nitriding or carburizing
Implementation Method 3
an induction heater, heats the shaft at a given temperature, thereby transforming a phase of the metal, thereby forming the hardened layer
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A medical instrument 20 with excellent operability is provided, including stick-shaped extra-narrow metal members 21 and 22, the extra-narrow members having a hardened layer 11 formed on the surface thereof without losing flexibility.