Seat Occupant Sensor with Elastomeric Mat and Force Translation Plates
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Solution Overview
Problem
Existing seat occupant detection systems face challenges in being cost-effective and adaptable to diverse seat geometries, materials, and firmness, as they often require complex and expensive components to accurately detect occupant presence.
Innovation Solution
A sensor apparatus comprising non-compliant force translation plates and an elastomeric mat with hollow protuberances that collapse to activate a switch mechanism when an occupant of sufficient weight sits, allowing for cost-effective adaptation to various seat configurations through the selection of mats with suitable stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure-responsive sensors are installed on the seat cushion to detect occupant presence, then occupant detection accuracy is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The sensor apparatus is segmented into distinct functional components: force translation plates that convert distributed seat forces into concentrated switch actuation forces, an elastomeric mat with hollow protuberances that provides mechanical amplification, and a simple switch mechanism. This segmentation allows each component to perform its specific function efficiently, achieving reliable occupant detection without requiring a complex integrated sensor system.
Solution Approach 2:
The elastomeric mat with hollow protuberances acts as an intermediary mechanical element between the seat cushion and the switch mechanism. When an occupant sits on the seat, the force is transmitted through the elastomeric mat, causing the hollow protuberances to collapse and indirectly actuate the switch. This intermediary mechanism amplifies the mechanical force and provides a reliable switching action without requiring sensitive electronic sensors.
2Reliability
If complex sensor systems are used to ensure accurate occupant detection across diverse seat types, then detection reliability is improved, but adaptability to different seat geometries and materials decreases
Solution Approach 1:
The sensor apparatus is designed as a universal solution that can be adapted to various seat types (different geometries, materials, and firmness levels) by simply changing the stiffness of the elastomeric mat. The force translation plates and switch mechanism remain the same across applications, while the elastomeric mat can be selected or engineered with appropriate mechanical properties to match specific seat characteristics, enabling the same basic design to reliably detect occupants across diverse seat configurations.
Solution Approach 2:
The key parameter that is changed to adapt the sensor apparatus to different seat types is the stiffness of the elastomeric mat. By adjusting this single parameter, the sensor system can be optimized for various seat firmness levels and materials without redesigning the entire apparatus. This parameter-based adaptation maintains detection reliability across diverse applications while avoiding the need for complex multi-configuration systems.
3Measurement precision
If traditional pressure sensors are used for occupant detection, then detection accuracy is maintained, but manufacturing cost increases
Solution Approach 1:
The sensor apparatus replaces expensive, complex pressure sensors with inexpensive mechanical components that can be manufactured at low cost. The force translation plates, elastomeric mat, and simple switch mechanism are all components that can be produced using conventional, cost-effective manufacturing processes. This approach achieves reliable occupant detection without the high manufacturing costs associated with electronic pressure sensor systems.
Solution Approach 2:
The invention substitutes electronic pressure sensing with a purely mechanical detection system. The force translation plates convert distributed mechanical forces from the seat into concentrated forces that collapse the hollow protuberances in the elastomeric mat, which in turn actuate a mechanical switch. This mechanical substitution eliminates the need for expensive electronic sensors while maintaining reliable occupant presence detection accuracy.
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 provides a reliable and cost-effective occupant presence detection system that can be easily adapted to different seat types, ensuring accurate detection while maintaining simplicity and low manufacturing costs.
Implementation Method 1
an elastomeric mat having a stiffness that allows hollow protuberances to collapse and activate a switch mechanism when an occupant having a specified or higher weight sits on the seating surface
Data Source
Figure 1
Figure 2~6
AI summary
An occupant presence sensor apparatus (12) disposed in a seat (10) includes first and second substantially non-compliant force translation plates (22, 24) generally parallel to the seating surface (18) of the seat (10), an elastomeric mat (26) disposed between the first and second force translation plates (22, 24), and a switch mechanism (28) disposed between the first and second force translation plates (22, 24) within an opening (52) formed in the elastomeric mat (26). The elastomeric mat (26) includes a distributed array of hollow protuberances (50a, 50b) that extend toward and contact the force translation plates (22, 24), and the mat (26) has a stiffness that normally provides a clearance between the switch mechanism (28) and one of the force translation plates (22, 24). When an occupant of specified or higher weight sits on the seating surface (18), the protuberances (50a, 50b) collapse and the force translation plates (22, 24) activate the switch mechanism (28).