Needle Assembly Miniaturization via Oblique Claw Locking
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Solution Overview
Problem
Existing safety needle assemblies face challenges in reducing the outer dimension of the protector sheath, leading to bulkiness, and struggle to prevent the needle tip from entering the back window of the protector when subjected to loads, especially with shorter cannulas.
Innovation Solution
A needle assembly with a protector that includes a claw-like portion that bends to lock the needle and a pair of barriers near the window to prevent the needle tip from entering, allowing for miniaturization and effective protection of the needle tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the locking projection is made long to facilitate bending, then the ease of operation is improved, but the outer dimension of the sheath increases leading to bulkiness
Solution Approach 1:
The locking projection is configured to extend in the width direction of the groove rather than the longitudinal direction, utilizing a different spatial dimension to achieve the necessary bending leverage while maintaining compact overall dimensions of the sheath
Solution Approach 2:
The locking projection has different dimensional characteristics in different directions: it extends further in the width direction to provide bending leverage, while maintaining minimal extension in the longitudinal direction to keep the sheath compact
2Reliability
If the cannula is locked to the fixing tab, then the reliability of needle containment is improved, but the needle tip may fall into the hole when load is applied, especially with shorter cannulas
Solution Approach 1:
The claw-like portion is pre-configured with an inclined surface that actively prevents the needle tip from approaching the hole by converting axial loads into lateral forces that push the needle away from the hole rather than allowing it to fall in
3Device complexity
If the claw-like portion extends in the width direction only, then the structure is simple, but the distance from fulcrum to force point is insufficient for easy bending
Solution Approach 1:
The claw-like portion is given an inclined configuration that extends in both the width direction and the longitudinal direction, utilizing three-dimensional spatial arrangement to increase the bending moment arm without significantly increasing overall structural complexity
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 solution achieves a miniaturized protector design while preventing the needle tip from entering the back window, enhancing safety and usability, especially with shorter cannulas.
Implementation Method 1
a claw-like portion (34) provided on the protector main body (31), which is bent by the needle (21) when the protector (22) is relatively displaced from the non-protection position to the protection position, allows the needle (21) to advance into the protector main body (31), and is elastically restored to lock the needle (21)
Data Source
AI summary
This needle assembly is provided with a needle having a needle tip, a needle hub, and a protector. The protector is displaceable between a non-protection position at which the needle is exposed and a protection position at which the needle tip is covered; has an opening formed elongated to match the needle, and includes a main body and a claw-like portion. The needle enters the main body from the opening to cover the needle tip when the protector is displaced to the protection position. The claw-like portion is bent by the needle when the protector is displaced to the protection position, allows the needle to advance into the main body, and is elastically restored to lock the needle when the needle enters the main body. The claw-like portion projects obliquely from the main body, extends across the opening in the width direction, and extends in the longitudinal direction.