Disposable Syringe Push Rod Deformable Stop Flange
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Solution Overview
Problem
Existing disposable syringes require excessive force to achieve an additional stroke for self-destruction, causing discomfort and increased effort for patients during use.
Innovation Solution
A cantilever structure is incorporated into the stop flange of the push rod, allowing the pushing and pressing portion to deform and facilitate the snap-fitting mechanism engagement with the needle seat, reducing the force needed for additional strokes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rigid stop flange is used to push the rubber piston for additional stroke, then the push rod can engage with the needle seat, but excessive force is required causing patient discomfort
Solution Approach 1:
The stop flange is transformed from a rigid structure to a dynamic structure with a deformable pushing and pressing portion. This portion can elastically deform during the additional stroke to reduce the force required, then recover to enable the snap-fitting engagement. The dynamic behavior allows the system to adapt force requirements during different phases of operation.
Solution Approach 2:
The physical state of the stop flange's pushing and pressing portion is changed from rigid to elastic/deformable. This parameter change allows the structure to absorb and release energy through deformation, reducing the peak force required during the additional stroke while maintaining sufficient force for engagement.
2Ease of operation
If the rubber piston is deformed to achieve additional stroke, then the push rod can engage with the needle seat, but the rubber piston deformation causes patient pains
Solution Approach 1:
The stop flange is segmented into a main body portion and a separate pushing and pressing portion. This segmentation allows the pushing and pressing portion to independently deform and absorb the deformation required for additional stroke, preventing the rubber piston from deforming and causing patient discomfort.
Solution Approach 2:
The deformable pushing and pressing portion acts as an intermediary between the rigid main body of the stop flange and the rubber piston. It absorbs the deformation energy that would otherwise be transmitted to the rubber piston, preventing patient discomfort while still enabling the additional stroke needed for engagement.
3Force
If a deformable pushing and pressing portion is added to the stop flange, then less force is required for additional stroke, but the structure becomes more complex
Solution Approach 1:
The stop flange is designed with local quality variation: the main body portion remains rigid for structural support and engagement, while only the pushing and pressing portion is made deformable. This localized deformation capability reduces overall structural complexity while achieving the force reduction goal.
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 design reduces the force required for the push rod to engage with the needle seat, minimizing patient discomfort and effort, while ensuring effective self-destruction of the syringe.
Implementation Method 1
the pushing and pressing portion is constructed in a way of being more likely to deform compared with the rubber piston such that when the rubber piston is stopped at the distal end of the barrel, only the pushing and pressing portion deforms as continuing to push and press the rubber piston
Data Source
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AI summary
A disposable syringe and a push rod (3) for use in the disposable syringe. The push rod (3) comprises a proximal end (11), a distal end (10) and an axis (12) extending through the proximal end (11) and the distal end (10). The distal end (10) of the push rod (3) is provided with a snap-fitting mechanism (14) and a stop flange (13) located at a proximal side of the snap-fitting mechanism (14). The stop flange (13) comprises a main body portion (15) formed about the axis (12) of the push rod (3) and a plurality of finger portions extending from the main body portion (15) in a direction away from the axis (12) of the push rod (3). A smaller push force continues to be applied to the push rod (3) upon completion of injection, thereby achieving an additional stroke needed when the distal end (10) of the push rod (3) snap-fits with a needle seat (2) and lessening patient's pains.