Needleless Injector Plunger Weakening for Overload Protection
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Solution Overview
Problem
Existing needleless injectors face safety risks due to the potential for excessive force applied to components during plunger pressurization, compromising the integrity of the injection process.
Innovation Solution
A needleless injector design featuring a plunger with a weakened part that deforms when excessive force is applied, preventing the plunger from reaching the deepest part of the housing and thus limiting the force exerted on the housing part, ensuring safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the plunger is designed with sufficient strength to withstand expected pressurization forces, then the structural integrity is maintained, but the housing part is at risk of damage when excessive load is applied
Solution Approach 1:
The plunger is pre-designed with a weakened part that will deform at a predetermined force threshold. This preliminary structural configuration ensures that when excessive force is applied during operation, the plunger will automatically deform to protect the housing part, preventing catastrophic failure and ensuring injection safety.
Solution Approach 2:
The plunger incorporates a weakened part with specific geometric parameters (reduced cross-sectional area, notches, or grooves) that change the local strength characteristics. This parameter modification creates a controlled deformation zone that activates at a predetermined force level, transforming the plunger from a uniformly strong structure to one with targeted weakness for safety purposes.
2Power
If the plunger moves to the deepest part of the housing part to maximize pressurization, then the ejection energy is optimized, but excessive force may be applied to the housing part
Solution Approach 1:
The weakened part is pre-configured in the plunger structure to deform when the applied force reaches a predetermined threshold. This preliminary design ensures that during the pressurization process, if the force becomes excessive, the plunger will automatically deform before reaching the deepest part of the housing part, thereby limiting the maximum force applied while still allowing optimized ejection energy under normal conditions.
3Reliability
If the plunger is designed to deform under excessive load, then the housing part is protected from damage, but the plunger cannot achieve full pressurization capability
Solution Approach 1:
The weakened part is designed with specific geometric parameters (cross-sectional area, notch depth, groove dimensions) that determine the predetermined force threshold for deformation. By carefully selecting these parameters, the plunger maintains full pressurization capability under normal operating conditions while ensuring automatic deformation and housing part protection when excessive load is applied, thus resolving the contradiction between capability and protection.
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 design guarantees the safety of the injection process by preventing excessive force from being applied to the housing part, even when unexpected loads occur during plunger pressurization.
Implementation Method 1
a plunger that is deformed by a weakened part so 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.