Needleless Injector Plunger Weakening for Excess Load Protection
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Solution Overview
Problem
Existing needleless injectors face risks of excessive load on components due to plunger pressurization, compromising injection safety.
Innovation Solution
A needleless injector design with a plunger featuring a weakened part that deforms when excessive force is applied, preventing the plunger from reaching the deepest part and ensuring the housing part receives forces within a safe range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plunger is designed with sufficient strength to withstand pressurization forces, then the injection function is reliable, but the risk of excessive load on components increases when unexpected loads occur
Solution Approach 1:
The plunger is designed with a weakened part that acts as a predetermined safety mechanism. When excessive force is applied during pressurization, the weakened part deforms to absorb the excess energy, preventing transmission of harmful forces to the housing and other components. This beforehand cushioning approach ensures that even when unexpected loads occur, the system protects itself through the pre-designed deformation path.
Solution Approach 2:
The weakened part converts the harmful excessive force into a beneficial deformation event. Instead of allowing the full force to damage components, the weakened part deforms in a controlled manner, transforming the excessive load into a safety feature that protects the overall system. The deformation absorbs energy that would otherwise be harmful, turning a potential failure condition into a protective mechanism.
2Power
If the plunger is designed to deliver sufficient ejection energy, then the substance is effectively ejected, but the force applied to the housing part may exceed the expected level
Solution Approach 1:
The weakened part is positioned to deform before the plunger reaches the deepest part of the housing part, cushioning the force transmission. This ensures that even when high ejection energy is delivered, the housing part receives forces within a safe range, as the weakened part absorbs the excess force through controlled deformation.
3Productivity
If the plunger is made rigid to maintain structural integrity, then the pressurization is efficient, but the safety against excessive load is reduced
Solution Approach 1:
The plunger is designed with non-uniform structural properties: most of the plunger maintains high rigidity for efficient pressurization, while a specific localized region (the weakened part) has reduced strength. This local quality differentiation allows the plunger to be rigid where needed for productivity, while having a safety mechanism where needed for reliability.
Solution Approach 2:
The plunger is segmented into functional regions: a strong main body for efficient pressurization and a weakened part for safety. This segmentation allows different parts of the same component to have different mechanical properties, optimizing both productivity and safety simultaneously.
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
Guarantees safety of injection by preventing excessive force from being applied to the housing part, even when unexpected loads occur during plunger pressurization.
Implementation Method 1
a plunger (80) that defines the accommodating space and is disposed to move in the housing part (2) by the ejection energy and pressurize the substance intended for injection. The plunger (80) includes a weakened part that causes a part of the plunger to deform such that, when force applied to the plunger exceeds predefined force
Data Source
AI summary
A needleless injector includes a housing part including an accommodating space that is configured to accommodate a substance intended for injection an actuator configured to generate an ejection energy and a plunger coupled to the housing part so as to define the accommodating space, including a weakened part and a distal end, and configured to receive the ejection energy from the actuator as a driving force. The plunger is further configured to move in the housing part by the driving force so that the distal end reaches to a deepest part of the housing part when the driving force is equal to or smaller than a predefined force, and deform at the weakened part by the driving force before the distal end reaches to the deepest part of the housing part when the driving force exceeds the predefined force.