Side-Hole Injection Needle Chamfering for Lower Piercing Resistance
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Solution Overview
Problem
Side-hole injection needles used in cosmetic surgery experience increased piercing resistance and risk of intradermal internal bleeding or blood vessel damage due to edge portions on the side surface opening, necessitating a reduction in piercing resistance.
Innovation Solution
The injection needle features a distal end side surface chamfered portion and a rear end side surface chamfered portion with gently curved surfaces at the edges of the side surface opening, reducing the piercing resistance by smoothing the edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a side-hole injection needle is used to spread medical solution widely in the skin by moving or rotating the needle, then the injection coverage is improved, but the piercing resistance increases and the risk of intradermal internal bleeding or blood vessel damage increases
Solution Approach 1:
The patent applies curvature by forming chamfered portions with gently curved surfaces at the edge portions of the side surface opening. This replaces sharp edges with curved surfaces, reducing piercing resistance when the needle is moved or rotated in the skin, while maintaining the side-hole structure for wide injection coverage.
Solution Approach 2:
The patent applies local quality by providing chamfered portions only at the edge portions of the side surface opening where the needle contacts the skin during movement. The main body of the needle retains its original structure, while only the critical edge regions are modified to reduce piercing resistance, thereby balancing injection coverage and reduced tissue damage.
2Strength
If the edge portions of the side surface opening are sharp to maintain structural integrity, then the needle strength is improved, but the piercing resistance increases and tissue damage risk increases
Solution Approach 1:
The patent applies curvature by forming chamfered portions with gently curved surfaces at the edge portions of the side surface opening. This replaces sharp edges with curved surfaces, reducing piercing resistance when the needle is moved or rotated in the skin, while maintaining the side-hole structure for wide injection coverage.
Solution Approach 2:
The patent applies parameter changes by modifying the geometric parameters of the edge portions through chamfering. The chamfered portions create a gradual transition at the edges, changing the local geometry from sharp to curved, which reduces stress concentration and piercing resistance while maintaining overall needle strength.
Data Source
AI summary
An injection needle includes a main body portion having a hollow cylindrical shape; a distal end portion having a curved outer shape, the distal end portion being joined to close a distal end of the main body portion; and a side surface opening portion opened on a side surface of the main body portion. A region surrounding the side surface opening portion has a substantially arc-shaped concave shape in a side view along an axial direction G in a state where the side surface opening portion is on an upper side. A distal end side surface chamfered portion having a gently curved surface is at a position corresponding to an edge on a distal end side of the concave shape. A rear end side surface chamfered portion having a gently curved surface is at a position corresponding to an edge on a rear end side of the concave shape.