Seating Load Sensor with Relief Holes to Absorb Strain Under Bending
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Solution Overview
Problem
Conventional seating load detecting devices face issues with accurate detection due to strain generated by perimeter differences between films when bent, leading to incorrect activation or failure to detect seating loads, especially when the device is arranged under a bent state.
Innovation Solution
A seating load detecting device featuring a band-shaped first and second film with a partition member including relief holes that absorb strain caused by perimeter differences, allowing accurate detection even when the device is bent, with the relief holes communicating with air passages to prevent water invasion and maintain functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the membrane switch is formed by bending to fit the seat cushion groove shape, then the device can be arranged on the seat cushion, but the perimeter difference between films generates strain causing incorrect sensor actuation
Solution Approach 1:
The partition member is divided into multiple segments: a bent portion that adapts to the seat cushion groove shape, and a flat portion that maintains structural stability. This segmentation allows different parts of the device to fulfill different functions - the bent portion provides adaptability while the flat portion prevents strain generation that would compromise sensor reliability
Solution Approach 2:
Different portions of the partition member are given different geometric properties - the bent portion has a curved cross-section to match the seat cushion groove, while the flat portion has a straight cross-section. This local differentiation of quality allows the device to simultaneously achieve adaptability where needed and reliability where strain must be avoided
2Measurement precision
If relief holes are provided in the partition member to absorb strain, then sensor actuation accuracy is maintained, but water may invade the sensor through the holes
Solution Approach 1:
The partition member acts as an intermediary structure between the bent portion and the sensor cells. By incorporating relief holes in the partition member rather than in the sensor films themselves, the design allows strain absorption while maintaining the integrity of the sensor actuation surfaces, preventing water invasion paths that would directly compromise sensor functionality
Solution Approach 2:
The relief holes, which could potentially allow water invasion, are strategically positioned and sized to primarily serve the beneficial function of strain absorption. The holes provide a controlled mechanism for the partition member to deform elastically under load, converting the potential harm of structural rigidity into the benefit of adaptive strain relief that maintains sensor 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 ensures accurate detection of seating loads by absorbing strain and preventing water invasion, maintaining the device's functionality and accuracy under bent conditions, thereby distinguishing between human and non-human occupants effectively.
Implementation Method 1
the relief hole 34 is provided between one pressure sensitive switch 20 which is provided closest to the bent portion 40 and the bent portion 40... the relief hole 34 can absorb such strain
Implementation Method 2
the relief holes communicating with air passages to prevent water invasion and maintain functionality
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
The object of the invention is to provide a seating load detecting device which can correctly detect a eating state of an occupant of a seat even when the device is arranged on a vehicle seat cushion with bending. The seating load detecting device includes a band shaped first film formed by a plurality of portions to be contacted, each portion being separated with a distance from each other forming a pressure sensitive switch for detecting a seating state of an occupant of a seat and a switch connecting wiring connecting the plurality of portions to be contacted, a band shaped second film disposed facing to the first film and formed by a plurality of portions to contact forming the pressure sensitive switch and contacting with or separating from the corresponding plurality of portions to be contacted and a partition member disposed between the first and the second films and formed with a plurality of penetration holes positioned opposite to the plurality of pressure sensitive switches and an air passage communicating with the plurality of penetrating holes and exposed to the atmosphere. The first and the second films, between which the partition member is interposed are attached to a seating surface of the seat under the films being bent, and the partition member includes a relief hole provided between a bent portion formed by the first and the second films when attached to the seating surface of the seat and one of the plurality of pressure sensitive switches positioned closest to the bent portion for absorbing a strain.