Body support cushion having multiple layers of phase change material
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Solution Overview
Problem
Memory foam body support cushions tend to 'sleep hot' due to reduced airflow and heat retention, leading to discomfort, as existing cooling technologies like phase change materials and gel provide only short-lived cooling and can be costly or mechanically complex.
Innovation Solution
A multi-layer foam cushion with phase change material (PCM) integrated into both the outer cover and the foam layers, combining non-reticulated and reticulated viscoelastic foams, along with high resilience foams, to enhance airflow and provide extended cooling through PCM layers in the comfort and support systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If memory foam material is used to provide body support and conformity, then body support effectiveness is improved, but heat retention increases causing the cushion to sleep hot
Solution Approach 1:
The patent combines memory foam material with phase change material (PCM) in a multi-layer construction. The PCM layers are integrated between the memory foam layers, creating a composite structure that maintains the body-contouring properties of memory foam while adding thermal regulation capabilities through PCM's phase change properties.
Solution Approach 2:
The patent utilizes phase change material that undergoes phase transitions (solid-liquid-solid) at specific temperatures relevant to human body temperature. When the PCM absorbs excess heat from the body, it melts (solid to liquid), absorbing latent heat and preventing temperature rise. When cooled, it solidifies again, releasing stored heat and maintaining a comfortable temperature range.
2Temperature
If phase change material is added to provide cooling sensation, then cooling effect is improved, but duration of cooling action is limited
Solution Approach 1:
The patent divides the PCM into multiple discrete layers distributed throughout the cushion structure, rather than using a single large PCM reservoir. This segmentation allows different PCM layers to activate at different times as the user moves and different portions of the cushion are compressed, extending the overall cooling duration.
Solution Approach 2:
The PCM layers are pre-positioned within the cushion structure during manufacturing, strategically located between memory foam layers where they can most effectively intercept body heat before it reaches the user. This preliminary placement ensures immediate cooling action upon contact.
3Temperature
If gel material is used to provide cooling, then momentary cooling sensation is improved, but heat absorption capacity is limited
Solution Approach 1:
The patent combines gel cooling material with phase change material in specific layers. The gel provides immediate cooling upon contact, while the PCM layers behind it provide sustained cooling as they undergo phase change, creating a multi-stage cooling system with greater total heat absorption capacity.
4Temperature
If cooling blankets with pumps are used to circulate coolant, then cooling effectiveness is improved, but device complexity increases
Solution Approach 1:
The PCM-based cooling system is passive and self-regulating. It automatically absorbs heat when the user's body temperature rises and releases heat when cooled, without requiring external power sources, pumps, or control systems. The phase change process occurs naturally in response to temperature conditions.
Solution Approach 2:
The patent replaces active mechanical cooling systems (pumps, circulating coolant) with a passive thermodynamic system based on phase change. This substitution eliminates complex mechanical components while maintaining effective cooling through the inherent properties of the PCM.
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 integration of PCM in both the cover and foam layers offers a prolonged cool dermal sensation, improving comfort by maintaining a lower temperature and reducing heat retention, thus addressing the heat-related issues of memory foam cushions.
Implementation Method 1
Portions of the outer cover and the foam cushion comprise PCM to provide an extended cool dermal sensation to a user resting on the cushion
Implementation Method 2
many mattresses now come with covers containing latent heat storage units, such as phase change material (PCM)
Implementation Method 3
Body support cushions made from temperature-sensitive viscoelastic material, such as TEMPUR® material
Implementation Method 4
the cushion in providing body support is partly a function of how well the memory foam responds to the contour of the user resting on the cushion
Implementation Method 5
one or more layers of the multi-layer construction may include reticulated viscoelastic foam
Data Source
Figure 1~3
Figure 2
Figure 2A~4A
AI summary
A body support cushion, e.g., mattress, has multiple foam layers, including a viscoekstic foam layer and a reticulated foam layer, and an outer cover. At least one of the foam layers and the outer cover each includes phase change material having latent heat properties that provide two intervals of dermal cooling.