Ring-Shaped Occupancy Sensor With Sealed 360° Triggering
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Solution Overview
Problem
Existing sensors for monitoring the occupancy of seating and lying furniture face challenges in maintaining lying comfort and reliability during cleaning and disinfection, particularly in hospitals and hotels, due to structural complexity and high costs, and often fail to trigger accurately due to liquid exposure.
Innovation Solution
A sensor design featuring a ring-shaped structure with a 360° triggering mechanism, a low overall height, and a sealed enclosure that prevents liquid ingress, allowing reliable operation without auxiliary constructions and maintaining comfort, using a piezoelectric actuator and transmitter arrangement for energy generation and wireless signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is positioned directly beneath the surface of the mattress to ensure reliable triggering, then the triggering reliability is improved, but the lying comfort is impaired
Solution Approach 1:
The sensor is repositioned from a vertical placement beneath the mattress surface to a horizontal integration within the mattress layer structure. This dimensional change allows the sensor to be triggered by lateral pressure distribution across the mattress while maintaining a comfortable lying surface, resolving the contradiction between triggering reliability and lying comfort.
2Object-affected harmful factors
If fully sealed sensors are used to protect against liquid ingress during cleaning, then the water resistance is improved, but the sensor retraction is impeded due to negative pressure formation
Solution Approach 1:
The sealing structure uses a flexible membrane that can deform during actuation and retraction cycles. This flexible seal allows the sensor to maintain water resistance while accommodating the pressure changes and mechanical movements required for reliable sensor retraction, eliminating the negative pressure problem caused by rigid sealing.
3Reliability
If auxiliary structures such as brackets or recesses are used to detect occupancy, then the triggering reliability is improved, but the device complexity and cost increase
Solution Approach 1:
The sensor is integrated directly into the mattress fabric and internal structure, merging the detection function with the existing mattress components. This eliminates the need for separate auxiliary structures like brackets or recesses, reducing overall system complexity while maintaining reliable occupancy detection through the mattress's natural pressure response.
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
Ensures reliable occupancy detection without affecting comfort or requiring additional structures, and withstands liquid exposure during cleaning, providing maintenance-free and low-radiation operation with enhanced triggering reliability and reduced structural complexity.
Implementation Method 1
a piezoelectric actuator and transmitter arrangement for energy generation
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to a sensor for detecting the occupancy of seating and reclining furniture that has a seat or reclining cushion, consisting of a housing (1) and a lid (2) movably arranged therein, wherein at least one spring element (5) is arranged between the housing (1) and the lid (2), and which has a trigger unit (3) that is connected to a transmitter (4). The trigger unit (3) consists of an actuator (31) that interacts with at least one lever (33) which is pivotably arranged in the housing (1) and is under the influence of the spring element (5) and which bears against the lid (2) with a contact element (24).