Stiffness adjustment device
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Solution Overview
Problem
Existing stiffness adjustment devices for bedding assemblies, such as mattresses and spring boxes, often experience involuntary movement, leading to unexpected changes in stiffness, and existing solutions complicate fabrication and actuation.
Innovation Solution
A bistable stiffness adjustment device utilizing a resilient element, such as a spring blade, that undergoes greater resilient bending in an intermediate position, providing resistance to movement between interference and non-interference positions, allowing for stable stiffness maintenance without preventing voluntary actuation, and incorporating a rotary part that can turn between these positions to restrict deformation without enlarging the device's footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ratchet device or guide slots are used to prevent involuntary movement, then stability is improved, but device complexity increases
Solution Approach 1:
The patent changes the physical state and geometric parameters of the resilient element to create position-dependent stiffness. By designing the element with varying cross-sectional properties along its length, it naturally provides stable equilibrium positions without requiring complex mechanical locking mechanisms like ratchets or guide slots.
Solution Approach 2:
The resilient element serves its own stabilization function through its inherent elastic properties and geometric design. It automatically maintains stable positions and prevents involuntary movement through its own structural characteristics, eliminating the need for separate stabilization components.
2Reliability
If the resilient element is designed to resist movement in intermediate positions, then stability is improved, but ease of operation may worsen
Solution Approach 1:
The system transitions from a static stabilization approach to a dynamic one where the resilient element's stiffness varies with position. The element is designed to be compliant during the transition phase (intermediate positions) and stiff at the target positions, allowing easy actuation while maintaining stability.
Solution Approach 2:
The resilient element is pre-configured with geometric properties that create resistance only when needed. The varying cross-section is designed beforehand to provide stabilizing force at equilibrium positions while remaining compliant during intentional transitions, anticipating and counteracting only the unwanted involuntary movements.
3Adaptability or versatility
If a rotary part is used to adjust stiffness, then adaptability is improved, but device footprint increases
Solution Approach 1:
The rotary adjustment mechanism is integrated within the existing spring assembly structure. The rotary part operates within the vertical space of the spring, nesting the adjustment function inside the existing footprint rather than adding external adjustment mechanisms that would increase the horizontal footprint.
Solution Approach 2:
The patent moves the adjustment mechanism from a horizontal plane to a vertical dimension by using a rotary part that operates along the spring's compression axis. This allows stiffness adjustment without increasing the horizontal footprint of the bedding assembly.
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 solution ensures stable and adjustable stiffness without involuntary changes, simplifying the device's operation and fabrication, and allows for simultaneous adjustment of multiple springs, maintaining selected stiffness while being easy to implement and operate.
Implementation Method 1
a resilient element which is subjected in the intermediate position to resilient bending which is greater than in the interference and non-interference positions
Implementation Method 2
when not stressed, the spring blade may be curved. Thus, the resilient bending in the intermediate position may be contrary to the curvature of the unstressed resilient blade, and the relaxation of the spring blade towards its naturally curved configuration may provide a return force towards the interference and non-interference positions
Data Source
AI summary
The invention relates to the field of furnishing. In particular, the invention relates to a stiffness adjustment device movable between an interference position for imposing a restriction on the deformation of a seat, back or bedding spring, and a non-interference position for releasing the spring from the restriction. The stiffness adjustment device comprises a resilient element, e.g. such as a flexible blade and, as it moves between the interference and non-interference positions it passes through an intermediate position in which the resilient element is subjected to resilient bending that is greater than in the interference and non-interference positions.