Remote Safety Switch Actuation with Spring Return and Magnetic Coupling
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Solution Overview
Problem
Existing safety switch actuation methods for elevators require direct access to the elevator shaft, posing safety risks and being time-consuming, and can result in failure to actuate the safety switch during emergency braking due to jammed or force-requiring Bowden cables.
Innovation Solution
A remote actuation device using a linear drive to activate and deactivate the pushbutton switch, allowing external control of the plunger without direct access, ensuring the safety circuit is properly opened and closed without relying on Bowden cable clearance or force, utilizing a return spring and magnetic coupling for reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the service technician goes into the elevator shaft to close the safety circuit, then the safety switch can be accessed and closed, but it is time-consuming and dangerous
Solution Approach 1:
The patent introduces a Bowden cable as an intermediary mechanism that transmits the actuating force from the safety switch to the brake device remotely. This allows the service technician to operate the safety switch from outside the elevator shaft, eliminating the need for direct access to the hazardous shaft environment while still achieving the desired circuit closure.
Solution Approach 2:
The patent replaces the direct mechanical connection requiring shaft access with a cable-based mechanical transmission system. The Bowden cable substitutes for direct physical access, allowing remote actuation of the safety switch through a mechanically equivalent but safer interface located outside the shaft.
2Ease of operation
If the Bowden cable is used to lift the actuating element, then the safety switch can be deactivated remotely, but the cable may jam or require too much force preventing proper actuation
Solution Approach 1:
The patent incorporates a cam mechanism with an inclined surface that dynamically converts the actuating force into vertical motion of the actuating element. The cam's geometry ensures that the force required to actuate the safety switch remains within acceptable limits throughout the motion range, preventing cable jamming and ensuring reliable operation.
Solution Approach 2:
The cam mechanism utilizes a curved inclined surface to transform the linear pull from the Bowden cable into the vertical displacement needed to actuate the safety switch. This curved geometry provides a mechanical advantage that reduces the force requirement and ensures smooth, jam-free operation of the cable system.
3Adaptability or versatility
If the Bowden cable does not have sufficient clearance, then the safety switch may not be actuated during emergency braking
Solution Approach 1:
The cam mechanism provides dynamic adaptation to varying clearance conditions. The inclined surface of the cam allows the actuating element to follow the cable's motion while maintaining proper engagement with the safety switch, ensuring reliable actuation even when cable clearance varies within acceptable ranges.
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
Enables safe and efficient remote operation of the safety switch, preventing unintended actuation and ensuring the elevator's safety circuit is correctly managed, reducing the risk of misoperation during emergency braking and eliminating the need for direct shaft access.
Implementation Method 1
a return spring (11) which can be compressed by the linear drive (4) and which, upon relaxation, moves the return actuator (12) and the plunger (3) coupled to it back to the starting position
Implementation Method 2
the plunger (3) is coupled to the return actuator (12) by engagement of a magnetic coupling (18)
Data Source
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AI summary
The invention relates to a safety switch actuation device (1) for keeping the pushbutton switch (2) activated and deactivated remotely, the actuation device (1) comprising a plunger (3) which can be brought by external probing from a standby position, in which it does not switch the pushbutton switch (2), to an active position, in which it keeps said pushbutton switch (2) actuated, characterized in that the actuation device (1) has a remotely controllable linear drive (4), a return spring (11) and a return actuator (12) and is designed in such a way that the plunger (3) can be coupled to the return actuator (12) by the remotely controllable linear drive (4), which is preferably driven by a Bowden cable (6), under tension of the return spring (11), which, after deactivation of the linear drive (4), is pressed by the return spring (11) into a position more remote from the pushbutton switch (2), thereby entraining the plunger (3) into its standby position.