Seat Occupant Sensor Lever Mechanism Perimeter Detection
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Solution Overview
Problem
Existing seat occupant sensing devices, such as plate-type and bladder-type sensors, are inefficient in detecting seating forces applied to the perimeter of a seat cushion, as they are typically designed for central contact areas, leading to increased costs and packaging difficulties when trying to detect forces on the perimeter.
Innovation Solution
A sensor assembly with a base and pivotably coupled levers that apply an actuation force proportional to the seating force, allowing detection of forces on the perimeter of the seat cushion without relying on deflection or deformation, and optionally using multiple levers and a control unit for enhanced detection capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If plate-type or bladder-type sensors are used to detect seating forces on the perimeter portion of the seat cushion, then the detection capability for perimeter forces is improved, but the cost and packaging difficulty increase
Solution Approach 1:
A lever mechanism is introduced as an intermediary between the seating surface and the force transducer. The lever pivots on a fulcrum and transfers the seating force applied at its first end to the force transducer at its second end, enabling indirect measurement of perimeter forces without requiring the transducer to be directly positioned under the perimeter area.
Solution Approach 2:
The force detection capability is extended from the vertical dimension (direct compression under the sensor) to include the horizontal dimension (perimeter contact points). By positioning the lever's sensing end at the perimeter while keeping the transducer in a centralized location, the system detects forces in multiple spatial locations through mechanical leverage rather than requiring multiple distributed sensors.
2Area of stationary object
If multiple sensors are arranged to detect seating forces on the perimeter portion, then the detection coverage is improved, but the device complexity and cost increase
Solution Approach 1:
The lever mechanism serves multiple functions: it acts as a force amplifier, a position translator, and a signal transmitter. A single lever-based force transducer assembly can detect forces applied at various perimeter locations by adjusting the lever's pivot point or sensing end position, eliminating the need for multiple dedicated sensors at different locations.
Solution Approach 2:
The patent combines the lever mechanism with the force transducer into an integrated assembly that can be packaged as a single unit within the seat cushion. This merging of mechanical leverage components with the sensing element simplifies packaging compared to distributing multiple separate sensors throughout the cushion structure.
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 effectively detects seating forces on the perimeter of the seat cushion with minimal mechanical loss, enabling the detection of occupants like children, pets, or packages, while maintaining cost-effectiveness and flexibility in packaging, and can differentiate between central and peripheral force applications.
Implementation Method 1
The lever defines a sensing end configured to be disposed proximate to the portion of the seat cushion such that the seating force operates on the sensing end. The lever defines an actuating end configured to apply an actuation force to the force transducer.
Implementation Method 2
The actuation force is proportional to the seating force
Data Source
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AI summary
A sensor system (10) and seat assembly (20) includes a sensor assembly (30) configured to detect a seating force (14) exerted on a portion of a seat cushion (26) of a seat. The sensor assembly (30) includes a base (32), a force transducer (34) configured to output a signal indicative of the seating force (14), and a lever (38) pivotably coupled to the base (32). The lever (38) defines a sensing end (44) configured to be disposed proximate to the portion of the seat cushion (26) such that the seating force (14) operates on the sensing end (44). The lever (38) also defines an actuating end (48) configured to apply an actuation force (50) to the force transducer (34). The sensor assembly (330) may comprise a plurality of levers (438). Each sensing end (444) of each lever (438) may be disposed in a separate location within the portion of the seat cushion (26). The sensor assembly (30) may be configured to detect a child (21) exerting a seating force (14) on a portion of the seat cushion (26).