Coil-in-Coil Spring Design for Non-Linear Mattress Support
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional coil springs exhibit a linear loading response, which may not provide the desired comfort and support, while foam mattresses offer non-linear support but have mechanical property degradation and higher production costs.
Innovation Solution
The development of coil-in-coil springs made from a continuous wire with varying spring constants, allowing for a soft feel initially, an intermediate feel as compression increases, and a firmer feel at further compression, mimicking the support of foam mattresses without mechanical degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional wire coil springs are used, then the mattress is inexpensive to manufacture, but the mattress provides a firm and rigid surface that lacks comfort
Solution Approach 1:
The patent applies nesting by placing an inner coil inside an outer coil to create a coil-in-coil spring structure. The inner coil has a smaller diameter and is positioned within the outer coil, allowing both coils to function simultaneously. This nested configuration enables the spring to provide non-linear support characteristics similar to foam mattresses while maintaining the cost-effectiveness and manufacturability of traditional metal spring systems.
2Ease of operation
If foam layers are used instead of innersprings, then non-linear support and improved comfort are provided, but production costs increase and mechanical properties degrade over time
Solution Approach 1:
The patent applies parameter changes by varying the spring rates of the inner and outer coils to create a non-linear loading response. The inner coil has a different spring rate than the outer coil, and as the mattress compresses, the interaction between these coils with different parameters produces a non-linear force-displacement relationship that mimics foam behavior. This allows metal springs to replicate foam's comfort characteristics while avoiding foam's cost and durability issues.
3Ease of operation
If foam layers are used instead of innersprings, then non-linear support is provided, but mechanical properties degrade over time
Solution Approach 1:
The patent applies this principle in reverse by using durable metal coils instead of degradable foam. The coil-in-coil spring system uses metal construction that resists mechanical degradation, permanent deformation, and loss of support properties over time. While foam provides initial comfort, the metal spring system maintains its mechanical properties and support characteristics throughout the mattress lifespan, offering long-term reliability.
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 coil-in-coil springs provide a non-linear loading response, enhancing comfort and support similar to foam mattresses while maintaining durability and cost-effectiveness.
Implementation Method 1
the spring exhibits a linear compression rate... Hooke's law, which states that the force (F) needed to extend or compress a spring by some distance (D) is proportional to that distance
Implementation Method 2
F=kD, where k represents the spring constant for a particular spring... the individual spring constants of a first spring portion, a second spring portion, and a third spring portion are variably combined
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multi-coil spring comprises a continuous wire forming having an outer coil having a height; an intermediate coil positioned within the outer coil and having a height less than the height of the outer coil; and an inner coil positioned with the intermediate coil and having a height less than the height of the intermediate coil.