Plastic Spring Structure for Consistent Dispenser Restoring Force
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Solution Overview
Problem
Conventional dispensers for flowable compounds, such as creams and lotions, face challenges in providing optimal spring characteristics and manufacturing efficiency, particularly in terms of spring force distribution and deformation, which affect the dispensing process and durability.
Innovation Solution
A dispenser design featuring a plastic spring with intermediate rings and spring struts that are curved in opposite directions, providing a wider intermediate ring width and varying run-in radii, allowing for increased spring force and reduced deformation, manufactured using injection molding for cost-effectiveness and optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional steel springs are used in dispensers, then the spring provides restoring force, but the spring undergoes plastic deformation over time which reduces reliability
Solution Approach 1:
The patent changes the material parameter from steel to plastic (polymer), fundamentally altering the spring's mechanical properties. This plastic spring maintains elastic deformation within its material limits, avoiding the plastic deformation that occurs with steel springs, thereby improving reliability and force consistency over time
Solution Approach 2:
The spring is designed as a composite structure combining plastic material with a specific geometric configuration (coils with varying wire diameters). This composite approach allows the spring to achieve both flexibility and durability, resolving the contradiction between maintaining spring force and preventing deformation
2Ease of manufacture
If intermediate rings with uniform width are used in the plastic spring, then the spring structure is simple, but the spring force distribution is not optimal
Solution Approach 1:
The intermediate rings are designed with non-uniform width, where the width varies along the axial direction. This local variation in geometric quality allows different sections of the spring to provide different stiffness characteristics, optimizing the overall spring force distribution while maintaining manufacturability through injection molding
3Force
If spring struts extend over large circumferential angles, then the spring provides stronger restoring force, but the spring requires more space and increases device complexity
Solution Approach 1:
The spring struts are designed to extend in the circumferential direction around the longitudinal axis, utilizing the third dimension (circumferential angle) to generate restoring force. This dimensional approach allows the spring to achieve strong restoring force within a compact axial space, reducing overall device complexity
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 enhances the spring characteristic by increasing force initially and maintaining a constant force during further depression, while minimizing plastic deformation, leading to improved dispensing efficiency and durability compared to conventional steel springs.
Implementation Method 1
A restoring device formed by a spring furthermore is provided between the head piece and the storage reservoir
Data Source
AI summary
A dispenser for dispensing flowable, for example liquid or paste-like, compounds, includes a storage reservoir for receiving the compound, and a preferably modular dispenser pump having an inlet channel and an outlet channel and a pump chamber delimited on the inlet and the outlet side by valves, and also having a head piece, the head piece having a dispensing opening, and a restoring device formed by a spring is further provided between the head piece and the storage reservoir. The restoring device is formed by a plastic spring having a lower spring washer and an upper spring washer, which are arranged substantially coaxially with one another, a respective plane spanned by each spring washer extending substantially perpendicular to a longitudinal axis of the plastic spring, and furthermore the spring washers being compressibly connected to one another by sprung struts extending over more than 90 degrees in the circumferential direction.