Corrugated Locking Device for Discharge Pump Stability
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Solution Overview
Problem
Discharge devices used for pharmaceutical and cosmetic applications, particularly those intended for long-term storage, face issues with material ageing that can lead to changes in control forces and potential failure, affecting the reliability and functionality of the device during use.
Innovation Solution
The locking device is designed with a zonally or circumferentially corrugated and/or polygonal cross-section, providing a corrugated projection and flexible locking elements that ensure a predeterminable frictional resistance and prevent significant modifications due to ageing effects, ensuring long-term functionality by avoiding stress peaks and allowing for elastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a smooth cylindrical locking device is used, then manufacturing is simple, but ageing effects cause significant changes in control forces and frictional resistance
Solution Approach 1:
The locking device is equipped with a corrugated cross-section featuring circumferential corrugations or polygonal structures instead of a smooth cylindrical shape. This curved/ridged geometry creates punctiform and linear contact areas with the working area, significantly reducing the frictional resistance and normal force interaction. The corrugated design remains manufacturable through standard molding processes while effectively minimizing ageing-related changes in control forces.
Solution Approach 2:
The locking device features localized corrugated structures at specific zones where contact with the working area occurs. These localized ridges or polygonal features are positioned to create controlled punctiform contact points, concentrating the interaction in specific areas rather than across the entire surface. This local quality modification reduces overall frictional resistance while maintaining structural integrity and manufacturability.
2Strength
If a large-area engagement between locking device and working area is used, then locking strength is high, but frictional resistance increases and is affected by ageing
Solution Approach 1:
The corrugated cross-section with circumferential ridges or polygonal features transforms the contact geometry from a large-area smooth surface interaction to punctiform and linear contact. The ridges create focused contact points that maintain locking strength through geometric interlocking while minimizing the surface area in contact, thereby reducing frictional resistance and its sensitivity to ageing effects.
Solution Approach 2:
The locking device's contact surface is segmented into multiple discrete ridges or polygonal features rather than a continuous smooth surface. This segmentation creates multiple punctiform contact points distributed around the circumference, distributing the locking force while reducing the total contact area and associated frictional resistance compared to a large-area smooth engagement.
3Ease of manufacture
If smooth cylindrical surfaces are used, then manufacturing is easy, but stress peaks occur during operation leading to potential failure
Solution Approach 1:
The corrugated cross-section with circumferential corrugations or rounded polygonal features eliminates stress concentration at sharp edges by providing continuous curved surfaces. The rounded transitions in the corrugated structure distribute stresses more uniformly during operation, preventing stress peaks that would occur at sharp corners or edges of polygonal features, while remaining compatible with standard molding manufacturing processes.
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 minimizes the impact of material ageing on the discharge device, ensuring consistent performance and preventing failure by maintaining a stable frictional resistance and allowing for multiple discharge strokes while preventing unintended operation.
Implementation Method 1
there can be a limitation to the normal force determining the frictional force. Thus, with such a locking device design and in conjunction with the working area, a long-term functionality of the discharge device is ensured.
Implementation Method 2
allowing for elastic deformation
Data Source
AI summary
A discharge device for manually producing a volume flow by a discharge stroke, having a medium reservoir for at least one medium, a discharge opening, a pumping device and a working area associated with the pumping device and which in the inoperative position has a detachable, positive connection to a holding area by means of a locking device is known.According to the invention the locking device in at least one plane orthogonal to a discharge stroke direction has an at least zonally or circumferentially corrugated and/or polygonal cross-section.Use for discharging a medium.