All-Plastic Compression Spring Assembly for Single-Stream Recycling
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Solution Overview
Problem
The presence of metal springs in dispensing pumps impedes the recycling process due to the need to separate them from plastic components, highlighting a need for an all-plastic spring system.
Innovation Solution
A compression spring assembly featuring a slotted tubular spring element and loading cones made from polymer materials, which are easily recyclable, with specific geometric designs to ensure functionality and durability, such as conical shapes and strain-reducing ribs, allowing for radial expansion and contraction to maintain the spring's operational effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal springs are used in dispensing pumps, then the spring provides reliable mechanical force, but the recycling process is impeded due to the need to separate metal from plastic components
Solution Approach 1:
The patent applies homogeneity by making the spring element from the same polymer material as the other pump components. The slotted tubular spring element is formed from a tensile polymer material, and the loading cones are also formed from polymer materials, creating a homogeneous all-plastic assembly that can be recycled together without separation.
Solution Approach 2:
The patent uses composite materials by creating a spring element through composite molding processes. The slotted tubular spring element and loading cones are formed as an integrated composite structure from polymer materials, combining the functions of spring elements and loading cones into a single recyclable component assembly.
2Volume of moving object
If the loading cone wall angle is less than 11 degrees, then the spring assembly diameter is reduced, but a friction lock is created that impedes operation
Solution Approach 1:
The patent applies parameter changes by optimizing the wall angle of the loading cone to be no less than 11 degrees. This specific angular parameter prevents friction lock while maintaining compact dimensions. The precise control of this geometric parameter resolves the contradiction between size reduction and operational ease.
3Ease of manufacture
If the spring element wall thickness is uniform, then the manufacturing process is simplified, but strain distribution is uneven reducing the spring element life cycle
Solution Approach 1:
The patent applies local quality by varying the wall thickness of the slotted tubular spring element at different locations. The non-uniform wall thickness distribution optimizes strain distribution throughout the spring element during compression and expansion cycles, extending its operational life while remaining manufacturable through appropriate molding 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
The all-plastic compression spring assembly facilitates single-stream recycling of dispensing pumps by ensuring the entire assembly, including the spring, can be made from a single plastic material, enhancing recyclability and extending the spring's life cycle while maintaining performance in dispensing liquids and lotions.
Implementation Method 1
Deformation of the tubular spring walls elastically stores energy which will return the spring to its normal at rest shape when released
Implementation Method 2
When released, the spring element elastically contracts, in turn creating an axial extension force, and returns the cones to their normal at rest positions
Data Source
AI summary
An all plastic compression spring assembly includes a slotted tubular spring element formed from a tensile polymer material and first and second loading cones received at opposing first and second ends of the slotted tubular spring element. The loading cones are axially compressible toward each other within the slotted tubular spring element whereby the slotted tubular spring element radially expands in tension to create an opposing radial contraction force, and in turn, an axial extension spring force. When released, the spring element elastically returns to its normal at rest shape, returning the cones to their normal at rest positions.