All-Plastic Compression Spring Assembly for Recyclable Dispensing Pumps

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Solution Overview

Problem

The presence of metal springs in dispensing pumps hinders the recycling process due to the need to separate them from plastic components, necessitating an all-plastic spring system for recyclability.

Innovation Solution

A compression spring assembly featuring a slotted tubular spring element and loading cones made from polymer materials, with specific wall angles and strain reducing ribs, allowing for radial expansion and contraction, and potentially hyperboloid shapes, enabling the entire dispensing pump to be molded from a single plastic material for easy recycling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a metal spring is used in the dispensing pump, then the spring provides reliable elastic force for nozzle return, but the metal spring impedes the recycling process due to the need to separate it from plastic components

Engineering Contradiction:

Improvespring force reliabilityVSAvoidrecyclability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies homogeneity by making the spring element and loading cones from the same polymer material, creating a homogeneous all-plastic assembly that can be recycled as a single material stream without separation of dissimilar materials

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent substitutes the traditional metal mechanical spring system with a polymer-based elastic system that uses the same material as the surrounding plastic components, replacing the metal-plastic mechanical system with an all-plastic elastic system

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Object-affected harmful factors

If the loading cone wall angle is less than 11 degrees, then the loading is gentle on the spring, but a friction lock is created that prevents proper operation

Engineering Contradiction:

Improvefriction lock preventionVSAvoidloading gentleness

Core Design Contradiction:

Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent applies parameter changes by optimizing the loading cone wall angle to be no less than 11 degrees, changing the geometric parameter to prevent friction lock while maintaining adequate loading gentleness for spring operation

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If the loading cone wall angle is greater than 11 degrees, then friction lock is avoided, but stroke length is minimized and overall spring assembly diameter increases

Engineering Contradiction:

Improvefriction lock avoidanceVSAvoidstroke length

Core Design Contradiction:

Ease of operationVSLength of moving object

Solution Approach 1:

The patent applies parameter changes by setting the loading cone wall angle to a specific value (no less than 11 degrees) that optimizes the balance between preventing friction lock and maintaining adequate stroke length

Inventive Principle:

Principle #35Parameter changes

4Ease of manufacture

If the spring element wall thickness is uniform, then manufacturing is simplified, but strain distribution is uneven causing reduced life cycle

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidspring life cycle

Core Design Contradiction:

Ease of manufactureVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by varying the wall thickness of the spring element, making certain sections thicker than others to distribute strain more evenly throughout the structure, with thicker walls in high-stress areas and thinner walls in low-stress areas

Inventive Principle:

Principle #3Local quality

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 all components are made from the same material, enhancing recyclability and extending the spring's life cycle while maintaining functionality.

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

Methodology Applied

Scientific EffectElasticity: Elasticity

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

Methodology Applied

Scientific EffectElastic recovery: Elastic Recovery

Data Source

PatentUS11754137B2Compression spring assembly and methods of using the same

Publication Date: 2023.09.12 SILGAN DISPENSING SYSTEMS CORP

AI summary

An all plastic compression spring assembly includes a slotted tubular spring element formed from a tensile polymer material and upper and lower loading cones received at opposing upper and lower ends of the slotted tubular spring element. The upper loading cone may be axially compressible towards the lower loading cone 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. In some dispenser configurations, the lower loading cone may be stationary or fixed within the dispensing head and the upper loading cone may be downwardly compressible toward the lower loading cone by movement of a nozzle head.