Retractable Needle Device Pinch Activation Mechanism
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Solution Overview
Problem
Conventional syringes with fixed or changeable needles lack a simple and effective mechanism for retracting the needle into a retraction tube using a pinching force, which is essential for preventing needle exposure and contamination.
Innovation Solution
A retractable needle device with a retraction mechanism activated by pinching pressure, featuring a needle alignment member, retraction tube, and a rearwardly-biased needle retraction mechanism, allowing the needle to be retracted into the tube while still inserted into a patient, using a syringe with a luer lock connector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retractable needle mechanism is added to conventional syringes, then needle safety and contamination prevention are improved, but device complexity increases
Solution Approach 1:
The retraction mechanism is integrated into the needle hub assembly, merging the retraction function with the existing needle mounting structure. This combines multiple functions (needle retention, retraction activation, and needle retraction) into a single integrated component, improving safety while minimizing the increase in overall device complexity.
Solution Approach 2:
The needle is retracted into a retraction tube that is nested within the hub assembly. The retraction mechanism components are nested within each other, with the needle sliding into the retraction tube, and the retraction tube being part of the hub structure. This nested arrangement provides retraction functionality without significantly increasing the external dimensions or complexity of the device.
2Reliability
If manual covers or guards are used to shield the needle, then needle exposure is reduced, but ease of operation deteriorates due to manual activation requirements
Solution Approach 1:
The retraction mechanism is designed to be automatically activated by the natural pinching motion that occurs when a user removes the needle from a patient. The opposed compressible portions are positioned to be squeezed between the user's thumb and finger during normal needle removal, causing automatic retraction without requiring the user to consciously activate a separate mechanism. This makes the safety feature self-activating based on natural user behavior.
3Force
If complex retraction mechanisms with cam members or pivotable actuators are used, then retraction force is improved, but ease of operation worsens due to complicated activation methods
Solution Approach 1:
The complex mechanical systems with cam members and pivotable actuators are replaced with a simpler spring-based mechanism. A compression spring provides the retraction force, and the activation method is substituted from complex mechanical actuation to simple pinching motion. This substitution maintains sufficient retraction force while dramatically improving ease of operation by using a natural human gesture rather than a complex mechanical sequence.
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
Enables easy and efficient needle retraction into a retraction tube using a pinching force, reducing the risk of needle exposure and contamination, and can be used with standard syringes and other medical devices.
Implementation Method 1
a rearwardly-biased needle retraction mechanism
Data Source
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AI summary
A retractable needle device attachable to the front of a fluid collection or infusion device such as a syringe, the retractable needle device comprising a housing having an engagement member, a slide support surface, a retraction cavity and a first pinch surface; a needle; a needle alignment member comprising a needle tube and a second pinch surface; and a needle retraction mechanism positioned within the needle tube and configured to bias the needle rearwardly; wherein the first and second pinch surfaces are configured so that a pinching force applied to them will cause relative lateral movement between the housing and needle alignment member. This translational movement from an injection position, wherein the needle is aligned with the syringe connector, to a retraction position, wherein the needle is aligned with the retraction cavity, allows the needle retraction mechanism to force the needle into the retraction cavity.