Injection Needle Oblique Bevel Design for Linearity
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Solution Overview
Problem
Conventional injection needles face challenges in penetrating tissues deeply and maintaining precision during dental and dermatological procedures, leading to anesthetic leaks and deviation, especially in intraligamentary and truncal anesthesia, due to deformation and lack of rigidity.
Innovation Solution
The design features a tubular needle with a main bevel and secondary bevel forming a single oblique incising edge, reducing deviation by subjecting the needle to opposing forces, and utilizing a thicker wall to increase rigidity and reduce deformation, with specific angles and dimensions optimizing penetration and linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the needle diameter is increased to increase rigidity, then the needle maintains better linearity during penetration, but the needle causes more tissue trauma and requires longer recovery time
Solution Approach 1:
The patent changes the geometric parameters of the needle point by introducing specific bevel angles (main bevel angle α between 10-30 degrees, secondary bevel angle β between 5-15 degrees) and wall thickness parameters (e ratio between 0.05-0.15). These parameter optimizations allow the needle to achieve sufficient rigidity and linearity without requiring an increase in overall diameter, thus avoiding excessive tissue trauma.
2Reliability
If the needle penetrates deeper into the ligament to prevent anesthetic leaks, then the anesthesia effectiveness is improved, but the needle twists and deviates from the intended trajectory
Solution Approach 1:
The patent employs asymmetric bevel design where the main bevel and secondary bevel have different angles and orientations relative to the needle axis. This asymmetric geometry creates a specific force distribution during penetration that enhances directional stability and prevents needle twisting, allowing deep penetration while maintaining trajectory precision.
Solution Approach 2:
The patent optimizes the wall thickness ratio e (between 0.05-0.15) and bevel angles to achieve the right balance between needle flexibility and rigidity. This parameter optimization allows the needle to penetrate deeply into the ligament without excessive twisting or deviation, maintaining both reliability and precision.
3Strength
If the needle wall thickness is increased to reduce deformation, then the needle rigidity is improved, but the needle manufacturing complexity increases
Solution Approach 1:
The patent defines specific parameter ranges for wall thickness ratio e (0.05-0.15), main bevel angle α (10-30 degrees), and secondary bevel angle β (5-15 degrees) that optimize needle rigidity while maintaining manufacturability. These parameter specifications allow standard manufacturing processes to produce needles with enhanced mechanical properties without requiring complex manufacturing techniques.
Data Source
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AI summary
The invention relates to an injection needle for injecting a pharmaceutical product into a human or animal body. The needle comprises a tubular body (1) with an end (3) intended to penetrate the human or animal body, this end (3) being provided with a primary bevel (4) and a secondary bevel (5) forming a point (7) of the needle. According to the invention, the secondary bevel (5) is arranged opposite the primary bevel (4) and forms with the primary bevel (4) a single cutting edge (6) oblique to a longitudinal axis (A) of the tubular body (1), the cutting edge (6) extending on either side of a median plane of the primary bevel (4) passing through the longitudinal axis (A) of the tubular body (1).