Hidden Dryer Door Latch Switch for Tamper-Resistant Sensing
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Solution Overview
Problem
Existing electrical switches in appliances like front-loading dryers are prone to contamination and tampering due to their exposed design, which can lead to malfunction and safety issues.
Innovation Solution
A hidden switch operator mechanism using a U-shaped metal clip and polymer jaw elements, integrated with a spring latch, that reduces exposure and contamination risks while maintaining functionality and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the switch operator is exposed and extends from the housing to be activated by door closure, then the switch can be easily operated by the door, but the switch operator becomes vulnerable to contamination and manual tampering
Solution Approach 1:
The patent introduces an intermediary mechanism where the door actuates the switch through the latch strike and jaw elements rather than directly pressing the operator. The operator is positioned behind the jaw elements and is actuated indirectly when the latch strike engages the jaws, which then transmit force to operate the switch. This intermediary arrangement protects the operator from direct contamination and tampering while maintaining operational functionality.
Solution Approach 2:
The patent repositions the switch operator from an exposed external position to a hidden internal position behind the jaw elements. By changing the spatial dimension and location of the operator from the front exterior to the rear interior of the latch assembly, the operator is shielded from contaminants and manual interference while still being actuated through the mechanical motion of the latch strike engaging the jaws.
2Reliability
If the switch operator is hidden behind the jaw elements to prevent tampering and contamination, then resistance to tampering improves, but the complexity of the mechanical linkage increases
Solution Approach 1:
The latch strike serves multiple functions: it engages the jaw elements to provide the latching function, and simultaneously actsuates the switch operator through the same engagement motion. This multi-functionality eliminates the need for separate actuation mechanisms, reducing overall complexity despite the hidden operator position. The spring element also provides both jaw biasing and operator actuation forces.
Solution Approach 2:
The patent merges the latching function and switch actuation function into a single integrated mechanism. The jaw elements and latch strike work together to both secure the door and operate the switch through the same mechanical engagement, combining two functions into one unified system rather than requiring separate mechanisms.
3Object-affected harmful factors
If a close fit between the sleeve and switch operator is used to prevent contaminant ingress, then contamination protection improves, but contaminants can accumulate and dry on the exposed surface causing jamming
Solution Approach 1:
The patent eliminates the sleeve and switch operator exposure by using the jaw elements and latch strike as intermediaries. The switch operator is positioned behind the jaw elements and is actuated through their engagement motion, completely shielding it from contaminant exposure. This removes both the close-fit sleeve requirement and the risk of contaminant accumulation on exposed surfaces that causes jamming.
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 prevents tampering and contamination, ensures smooth operation, and maintains latching functionality even in extreme conditions, such as a fire, while reducing the overall depth and complexity of the switch design.
Implementation Method 1
a spring element biasing the jaws toward each other so that they may separate to receive the latch strike
Implementation Method 2
The switch operator may slide within a sleeve that provides for mechanical support to the switch operator guiding it in axial translation when the switch operator is pressed by the door
Implementation Method 3
The opposed jaw elements are a polymer material in form of rounded bars
Data Source
Figure 1~2
Figure 3a~3b
Figure 4a~4b
AI summary
A latch switch assembly for an appliance or the like provides spring- loaded jaws (25) to retain a latch strike (24) when a door (16) of the appliance (10) is closed and a switch operator positioned behind spring-loaded jaws (25) be activated by the latch strike (24) when it is received.