Coil spring for resilient unit
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Solution Overview
Problem
Existing coil springs in resilient units, such as mattresses, waste material due to the reduced or zero pitch at the axial ends, which contribute minimally to resilience, leading to inefficiency and material waste when stacked.
Innovation Solution
A coil spring design with distinct first and second spring portions and a transition portion of reduced pitch, allowing all coils to contribute to resilience, reducing material waste by eliminating the need for turned-in ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pitch of the end coils is reduced or zero to prevent wire projection and discomfort, then comfort and safety are improved, but material waste increases because these coils contribute little to resilience
Solution Approach 1:
The spring is divided into three distinct segments: a first spring portion with normal pitch, a transition portion with reduced pitch, and a second spring portion with normal pitch. This segmentation allows each portion to serve its specific function while minimizing material waste in the transition zone.
Solution Approach 2:
The transition portion is designed with locally reduced pitch specifically where needed for comfort, while the majority of the spring (first and second spring portions) maintains normal pitch for optimal resilience. This localized modification minimizes the amount of material that does not contribute to spring function.
2Productivity
If springs are stacked axially to maximize the number of springs in a mattress, then productivity and space utilization are improved, but material waste increases due to the turned-in ends occupying space
Solution Approach 1:
By segmenting the spring into functional portions, the design allows springs to be stacked more efficiently. The transition portion with reduced pitch is minimized, allowing tighter stacking of springs while maintaining comfort benefits.
Solution Approach 2:
The pitch parameter is changed locally in the transition portion rather than throughout the entire spring. This allows the spring to maintain its functional length and resilience characteristics while reducing the space occupied by non-functional coil portions, enabling more springs to be stacked in the same volume.
3Loss of substance
If the pitch of the transition portion is reduced to eliminate turned-in ends, then material efficiency is improved, but the complexity of the spring design increases
Solution Approach 1:
The spring is segmented into three portions with clearly defined functions, making the design systematically organized rather than arbitrarily complex. Each segment serves a specific purpose, which simplifies the overall design logic despite the varied pitch characteristics.
Solution Approach 2:
The complexity is localized to the transition portion, which is a small segment of the overall spring. The majority of the spring (first and second spring portions) maintains simple, uniform characteristics, so the overall complexity increase is minimal while achieving significant material efficiency gains.
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
Saves 25% of material by eliminating unnecessary turned-in ends, while maintaining comfort and resilience, and allows for more efficient use of spring material.
Implementation Method 1
The spring comprises a plurality of coils about a spring axis, extending from a first axial end to a second axial end... the pitch of the transition portion is less than the pitch of the first and second spring portions
Data Source
AI summary
A single, continuous coiled spring, generally at 400, is formed into two distinct spring portions 400A and 400B, of generally constant pitch, separated by a transition portion 450 approximately half-way along the spring 400. The transition portion 450 comprises at least one turn which is of a reduced pitch in the example, but which may be of a zero pitch or even a negative pitch. The spring is encased in a continuous pocket P. In this case, the transition portion 450 includes a substantially flat turn. The spring portions 400A and 400B comprise a common portion of spring material in this case spring wire and the coils are substantially continuous throughout the overall spring 400.