Ophthalmic Tweezers with Centering Means for Precision
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Solution Overview
Problem
Current surgical tweezers for ophthalmological surgery face challenges such as precision loss due to hinge slack, inadequate stiffness, degradation from sterilization, and misalignment of metal points, particularly in microsurgery where precise and stable instruments are crucial.
Innovation Solution
The design features U-shaped metal pins with centering means, such as fins and wedge-shaped complementary portions, to ensure accurate alignment and stability of the working points, along with handle elements that control stiffness and prevent distortion, using materials like metal injection molding and plastics for enhanced durability and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If tweezers are made from two metal blades hinged together, then the active ends can be precise initially, but the precision decreases over time due to hinge slack
Solution Approach 1:
The tweezers are divided into distinct functional segments: a resilient body portion made of flexible material that provides the hinge mechanism, and separate active portions made of metal that perform the surgical function. This segmentation allows the hinge to be made from material optimized for flexibility rather than precision, while the metal active portions maintain their precision.
Solution Approach 2:
The invention uses composite construction with the body portion made of flexible material (such as plastic or elastomer) and the active portions made of metal. This composite approach allows each material to contribute its optimal properties: the flexible material provides resilient hinge action without slack, while the metal portions provide precise, stable active ends that do not degrade over time.
2Ease of manufacture
If tweezers are made from plastics material to reduce costs, then manufacturing cost decreases, but the active portions lack fineness and hardness
Solution Approach 1:
The invention applies different material qualities to different parts of the tweezers: the body portion uses flexible material suitable for cost-effective manufacturing and resilient action, while the active portions use metal material that provides the necessary fineness, hardness, and precision for surgical applications. Each part has the local quality appropriate to its function.
Solution Approach 2:
The tweezers combine plastic or elastomer material for the body with metal material for the active portions. This composite construction allows the majority of the device (the body) to be manufactured cost-effectively from molded material, while the critical active portions maintain the fineness and hardness requirements through metal construction.
3Ease of operation
If the plastics portion is made more flexible to improve handling, then ease of operation increases, but the flexibility becomes unstable and degrades quickly due to sterilization
Solution Approach 1:
The invention changes the material parameter from plastic to a flexible material with superior sterilization resistance. The flexible material is specifically selected to maintain its mechanical properties and flexibility stability even after repeated sterilization cycles, while still providing the necessary ease of operation.
Solution Approach 2:
The use of composite materials allows the body portion to be made from flexible material that is specifically chosen for its sterilization resistance. This material maintains its flexibility and mechanical properties stable over time and through multiple sterilization procedures, unlike standard plastics that degrade.
4Manufacturing precision
If centering means are incorporated in metal portions to ensure alignment, then manufacturing precision increases, but device complexity increases
Solution Approach 1:
The invention extracts the centering function from the metal active portions and relocates it to the flexible body material itself. The flexible material inherently provides alignment and centering through its structural design, eliminating the need for separate centering means such as studs and holes in the metal parts.
Solution Approach 2:
The flexible material is designed with local structural features that provide centering and alignment functions at the appropriate location. Rather than adding complexity to the metal portions, the centering capability is built into the flexible body material where it naturally occurs during closure.
Data Source
AI summary
The invention provides tweezers for microsurgery, in particular opthalmological surgery, the tweezers comprising a one-piece working part (1) of U-shape, with the free ends (2a, 3a) of each branch (2, 3) being shaped into a point, the part being derived from a flat blank of thickness (e) constituting the dimension perpendicular to the plane (P) in which the branches (2, 3) move, and elements for manipulating the working part together forming a handle for gripping the tweezers, wherein each element is in the form of an elongate body (4, 5) presenting a convex outside surface (4a, 5a) and a substantially plane surface (4b, 5b) having a longitudinal groove (6, 7) hollowed out therein to house one of the branches (2, 3) of the working part (1), the end of each handle element facing towards the points being provided with centering means (8a, 8b, 9a, 9b) co-operating with a complementary centering member of the corresponding end of the other element.