Retraction Plunger Assembly with Damping for Controlled Needle Safety
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Solution Overview
Problem
Existing retraction syringes face challenges in providing a controlled and safe needle retraction mechanism that is user-friendly, cost-effective, and compatible with various needle assemblies, while ensuring safety features are maintained and manufacturing complexity is minimized.
Innovation Solution
The development of a retraction plunger assembly with a biasing member and a housing system that allows for controlled needle retraction, enabling the syringe to accept various needle assemblies and facilitating selection of needle sizes, with a mechanism that maintains the biasing member in an energized state for controlled retraction and locking the plunger in place after use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a compressed spring mechanism is used for needle retraction, then the needle automatically retracts into the barrel, but excessively forceful retraction causes blood splattering and manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by introducing a damping mechanism that modifies the force parameters during needle retraction. The damping element (such as a dashpot or viscous damper) provides velocity-dependent resistance to the retraction motion, transforming the uncontrolled high-velocity spring-driven retraction into a controlled, slower movement that prevents blood splattering while maintaining automatic retraction functionality.
Solution Approach 2:
The patent uses an intermediary damping mechanism between the spring and the needle assembly. This intermediary element (damping element) absorbs excess kinetic energy and controls the retraction velocity, acting as a mediator that prevents direct transmission of excessive forces from the spring to the needle and surrounding tissues, thereby eliminating blood splattering.
2Reliability
If a specialized needle assembly is used for retraction, then needle retraction is achieved, but replacing defective needles or selecting desired needle sizes becomes difficult
Solution Approach 1:
The patent applies segmentation by dividing the needle assembly into separable components: a reusable syringe body containing the retraction mechanism and a replaceable needle component. This modular segmentation allows users to easily replace defective or size-mismatch needles while retaining the reliable retraction safety features in the main syringe body, thereby maintaining both reliability and adaptability.
Solution Approach 2:
The patent implements universality by designing a standardized interface between the syringe body and needle assembly that accommodates multiple needle sizes and types. The universal coupling mechanism allows the same retraction-safe syringe body to work with various needle configurations, enabling both safety maintenance and needle selection flexibility.
3Reliability
If mechanisms are added to prevent inadvertent needle retraction, then safety is improved, but manufacturing costs and design complexity increase
Solution Approach 1:
The patent applies self-service by designing a retraction mechanism that automatically performs the safety function without requiring additional complex control systems. The spring-loaded needle assembly with damping element provides self-regulating retraction control, where the system inherently prevents inadvertent retraction through its mechanical design while maintaining controlled automatic retraction when needed, eliminating the need for extra sensors, actuators, or control electronics.
4Object-affected harmful factors
If controlled retraction rate is implemented, then blood splattering is reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies the principle of using simple, inexpensive damping elements that can be integrated into the needle assembly or syringe body. These disposable damping components (such as viscous dampers or friction-based mechanisms) provide effective controlled retraction at minimal cost and complexity, avoiding the need for expensive active control systems while achieving blood splattering reduction.
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
This solution provides a controlled and safe needle retraction process, reduces the risk of blood splattering, and allows for easy selection of needle sizes, enhancing user safety and operational ease while maintaining manufacturing efficiency.
Implementation Method 1
a biasing member disposed at least partially within the plunger
Data Source
AI summary
The present embodiments provide for a syringe and a retraction plunger assembly configured to accept various retractable needle assemblies, which are capable of cooperating to provide a retraction safety syringe. In particular, the syringe includes a barrel and a retraction plunger assembly comprising a control unit attached to a plunger and releasably engaged to a housing, and at least one biasing means disposed within the plunger assembly. Upon completion of dose delivery via a retractable needle, the control unit disengages from housing and the biasing member retracts the plunger and a connected needle into the barrel. Various elements are configured to prevent further use of the syringe. The control unit can be used to control a rate of needle retraction.