Contamination Resistant Push Button Switch Operator Assembly
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Solution Overview
Problem
Modern appliances, such as front-loading washing machines, face contamination issues that cause the pushbutton switch operator to stick in an activated position due to the accumulation of substances like water, bleach, and detergent, leading to potential jamming and improper operation.
Innovation Solution
A pushbutton switch operator assembly with a support structure removed from the opening through which the switch operator extends, featuring a drain port and a rearward collar to divert contamination, a helical compression spring for biasing, and a key element to prevent rotation, ensuring reliable operation and resistance to contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the sleeve conforms closely to the switch operator to prevent contaminant ingress, then contamination resistance is improved, but the switch operator may jam within the sleeve when contaminants accumulate and dry on the outer surface
Solution Approach 1:
The support structure (sleeve) is removed from the opening area, allowing the switch operator to extend through a larger opening without close contact support. This extracts the supporting function from the opening region while maintaining contamination resistance through alternative means (rearward collar blocking when extended, drain passage for contaminants).
Solution Approach 2:
The support function is segmented into two parts: (1) the rearward collar on the switch operator that blocks the opening when fully extended, and (2) the drain passage that safely conducts contaminants away from the housing. This segmentation allows the opening to be larger while still providing support and contamination protection.
2Reliability
If the opening through which the switch operator extends is enlarged to prevent jamming, then switch operation reliability is improved, but contamination may enter through the larger opening
Solution Approach 1:
The rearward collar on the switch operator is designed to automatically block the opening when the switch operator reaches its fully extended position. This preliminary blocking action prevents contaminant ingress at the critical moment when the opening is most exposed, while allowing the opening to remain large during normal operation.
Solution Approach 2:
The drain passage serves as an intermediary pathway that allows contaminants to enter through the enlarged opening but then safely conducts them away from the housing through a dedicated drainage route, preventing harmful accumulation while maintaining reliable switch operation.
3Reliability
If the support structure is removed from the opening to prevent interference with switch operator movement, then switch operation reliability is improved, but the switch operator loses mechanical support
Solution Approach 1:
The support structure (sleeve) is extracted from the opening region and relocated to the interior of the housing. This removes the interfering element from the critical movement zone while preserving the support function through alternative configurations (rearward collar and drain passage system).
Solution Approach 2:
The support function transitions from a lateral sleeve structure at the opening to an axial rearward collar structure on the switch operator itself. This dimensional change allows support to be provided from the rearward direction rather than laterally, eliminating interference with movement while maintaining structural support.
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 resists contamination, preventing jamming and ensuring reliable operation by diverting contaminants away from the switch operator's movement path and using a spring-biased mechanism to maintain the switch in a centered position, reducing the risk of improper activation.
Implementation Method 1
a support structure positioned within the housing allowing the switch operator to move along an axis to project through the opening in the housing in an extended state and to retract at least in part into the housing in a retracted state
Implementation Method 2
The housing may include a drain port for conducting liquid carried from outside the housing along the switch operator shaft into the housing out of the housing along the drainage path removed from the contacts
Data Source
AI summary
A switch suitable for use in contaminated environments provides for internal support of the operator allowing an oversized opening in the housing of the switch through which the operator extends. In this way contamination on the outer surface of the operator may be accommodated without a jamming of the operator in the retracted position.