Optical Safety Switch Plunger for Contact Reliability
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Solution Overview
Problem
Safety switches can fail to a dangerous configuration due to damage or detachment of components, allowing electricity to be supplied to machinery even when the door is open, posing a risk to users.
Innovation Solution
Incorporating a signal emitter and detector, along with control circuitry, to ensure that electricity is only supplied when the actuator is engaged and the signal is detected, preventing unintended contact between bridge and fixed contacts, even if the switch is damaged or partially detached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety switch uses a mechanical contact system, then the device complexity is low, but the reliability deteriorates because the contacts may close due to damage or detachment
Solution Approach 1:
The patent replaces the purely mechanical contact system with an optical detection system. A light source emits light through a window in the plunger, and a photodetector detects the light. This optical system monitors the position of the plunger and control mechanism, providing a non-contact method to verify proper engagement and prevent false contact closure due to mechanical damage or detachment.
Solution Approach 2:
The patent introduces an optical intermediary (light) between the mechanical components to verify their proper functioning. The light passes through the plunger window only when the control mechanism is in the correct position, providing an intermediate verification step that ensures the mechanical system is not damaged or detached before allowing contact closure.
2Object-affected harmful factors
If the safety switch allows contact closure when actuator is engaged, then the productivity is improved, but the safety deteriorates because damaged components may allow unintended contact closure
Solution Approach 1:
The patent implements a feedback mechanism where the photodetector continuously monitors the position of the plunger and control mechanism through light detection. This feedback loop ensures that contact closure only occurs when the optical sensor confirms proper engagement, preventing unintended closure even if mechanical components are damaged. The system feedbacks the actual state of engagement to the control circuitry, which then决定是否允许接触闭合。
3Reliability
If the safety switch uses additional detection components, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent designs the plunger with a multi-functional window structure that serves both as a mechanical component for contact closure and as an optical element for light transmission. This universal design allows the same component to fulfill multiple functions, reducing the need for separate dedicated optical components and minimizing the increase in overall device complexity.
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 the safety switch fails to a safe configuration when components are detached or damaged, preventing electricity supply unless the actuator is properly engaged, thus reducing the risk of injury and enhancing operational safety.
Implementation Method 1
a signal emitter and a signal detector positioned in the body; the contact plunger, or a structure between the contact plunger and the control mechanism, being arranged to selectively allow or prevent passage of an emitted signal from the signal emitter to the signal detector
Data Source
AI summary
A safety switch that includes a body, a number of contacts, a movable plunger, a signal emitter, and a signal detector. The signal emitter and signal detector are positioned proximate the plunger and configured to assess the operability of the safety switch. The plunger is configured to selectively allow or prevent passage of a signal emitted from the signal emitter toward the signal detector depending on a position of the plunger. Control circuitry in connection with the signal detector is arranged to generate a control signal based on the detection of the emitted signal and configured to control operation of the safety switch independent of the relative position of the number of contacts.