Asymmetric Bevel Injection Needle for Painless Hard Tissue Penetration
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Solution Overview
Problem
Conventional penetrating injection needles are inefficient in delivering anesthesia to hard tissues due to tissue displacement and pain during injection, and the positioning markings on existing needles do not allow for accurate alignment of the bevel for painless injection.
Innovation Solution
A penetrating injection needle with a secondary bevel arranged opposite the main bevel forms a cutting edge, enabling the needle to cut tissues in a helical motion with a significant circumferential component, reducing tissue displacement and pain, and featuring a mark on the base for correct positioning of the main bevel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If conventional penetrating injection needles with triple bevels (lancet or back cut) are used, then the needle can penetrate into hard tissue, but the penetrating power is mediocre and tissue displacement occurs causing pain
Solution Approach 1:
The patent changes the geometric parameters of the bevels, specifically setting the main bevel angle between 5-15 degrees and the secondary bevel angle between 15-30 degrees, creating an asymmetric configuration that optimizes both penetration force and tissue displacement reduction. This parameter optimization resolves the contradiction between penetrating power and tissue displacement.
Solution Approach 2:
The patent employs asymmetric bevel configuration where the main bevel and secondary bevel have different angles and positions, with the secondary bevel arranged opposite the main bevel. This asymmetric design creates a cutting edge that reduces tissue displacement while maintaining penetrating power, directly addressing the technical contradiction.
2Ease of operation
If the marking is positioned on the side of the bevel for easy visibility, then the practitioner can see the mark, but the main bevel cannot be positioned flatly on the mucosa or skin for painless injection
Solution Approach 1:
The patent moves the marking from a two-dimensional side position to a three-dimensional position on the distal end of the needle, specifically on the plane of the secondary bevel. This dimensional change allows the marking to be visible while the main bevel remains properly positioned for painless injection, resolving the contradiction between mark visibility and injection comfort.
Solution Approach 2:
The secondary bevel plane serves as an intermediary carrier for the marking, separating the marking function from the main bevel positioning function. This allows the marking to be visible without interfering with the proper orientation of the main bevel during injection.
3Measurement precision
If the point angle is made small for precise injection, then injection precision improves, but the angles formed by intersection of bevels become close to or greater than 60 degrees reducing penetrating power
Solution Approach 1:
The patent optimizes the point angle to between 30-60 degrees and adjusts the bevel intersection angles to be less than 60 degrees, creating an asymmetric configuration that maintains both precision and penetrating power. This parameter optimization resolves the contradiction between injection precision and penetrating capability.
Data Source
AI summary
A penetrating injection needle for the injection of a pharmaceutical product into a human or animal body. The needle includes a tubular body having two opposing ends, a first end for connection to a device for driving the needle in rotation and pumping a product, and a second end for penetration of the human or animal body and including a main bevel and at least one secondary bevel. The secondary bevel or bevels is/are arranged in opposition relative to the main bevel and form a cutting edge and a needle point with the main bevel.