Telescoping Mattress Spring Assembly With Fabric Sleeve Preload
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Solution Overview
Problem
The existing telescoping spring assemblies in mattresses suffer from 'stickiness' due to frictional engagement between inner and outer members, leading to unintended reactions under external loads and a disruptive popping sound when returning to their extended position, primarily because the preload is transmitted to the tubular members.
Innovation Solution
A fabric sleeve is fitted around the coil spring to apply a compression preload, preventing the transmission of preload to the tubular members and eliminating the need for spacers of special lengths, allowing the spring assembly to move freely without sticking and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a spacer of special length is used to apply preload to the coil spring, then the desired firmness and preload characteristics are achieved, but the preload is transmitted to the tubular members causing frictional engagement and stickiness
Solution Approach 1:
The fabric sleeve acts as an intermediary element between the coil spring and the tubular members. It applies the compression preload to the coil spring while preventing the transmission of this preload to the inner and outer tubular members, thereby eliminating the frictional engagement and stickiness problem that occurs when spacers are used
2Manufacturing precision
If the preload is applied to the coil spring using a spacer, then the spring assembly can be preloaded to control firmness, but the engagement of opposing shoulder surfaces generates a disruptive popping sound
Solution Approach 1:
The fabric sleeve serves as a mediator that isolates the preload application from the tubular members. By wrapping around the coil spring and applying compression preload directly to the spring coils, it prevents the transmission of forces that would cause the inner and outer members to engage with shoulder surfaces, thereby eliminating the popping sound
Solution Approach 2:
The fabric sleeve is a flexible enclosure that wraps around the coil spring. This flexible film structure allows the application of compression preload to the spring while accommodating the spring's movement and deformation, preventing rigid force transmission that would generate noise
3Adaptability or versatility
If spacers of different lengths are used to vary firmness in different support zones, then individualized performance is achieved, but the device complexity increases
Solution Approach 1:
Instead of varying the physical dimensions of spacers, the invention achieves different firmness levels by changing the compression preload parameter applied to the coil springs. The fabric sleeve allows for adjustable preload through mechanisms such as varying the number of wraps, wrap tension, or fabric material properties, providing adaptability without increasing assembly 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 fabric sleeve maintains the preload on the coil spring, preventing 'stickiness' and the popping sound, enabling individualized performance without the need for spacers and providing quieter operation by absorbing acoustic energy.
Implementation Method 1
a coil spring arranged to bias the outer member in the extension direction relative to the inner member
Implementation Method 2
providing quieter operation by absorbing acoustic energy
Data Source
AI summary
A spring assembly includes telescopically adjustable inner and outer members biased in an extension direction by a coil spring. A non-stretch fabric sleeve fitted about an inner diameter and an outer diameter of the coil spring is closed at its opposite ends to apply a compression preload to the coil spring. The fabric sleeve prevents transmission of the preload to the inner and outer telescoping members, thereby eliminating stickiness and the popping sound that are drawbacks of the prior art, and the fabric sleeve also provides general noise reduction when the spring assembly changes length.