Armrest Emergency Stop Using Optical Signal Interruption
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Solution Overview
Problem
Existing stairlift emergency stop systems are cumbersome, expensive, or too large for armrest integration, lacking an electronically latching system that is easy to operate and ensures safety.
Innovation Solution
A stairlift safety system utilizing an electromagnetic signal-based mechanism with a movable vane and activator, integrated into the armrest, allowing non-latching emergency stop operation and fault detection, ensuring easy installation and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional emergency stop button with direct opening characteristics is used, then the emergency stop function is reliable, but the button is too big, too expensive, or both to fit into the armrest of the stairlift
Solution Approach 1:
The patent replaces the traditional mechanical emergency stop button with an electronic latching system that uses electromagnetic signals and a microcontroller. The system uses an optocoupler with LED and phototransistor to detect button presses electronically, eliminating the need for large mechanical contacts and spring-loaded elements. This electronic approach allows the emergency stop function to be integrated into the existing armrest without requiring additional space or increasing cost.
Solution Approach 2:
The patent integrates the emergency stop button functionality into the existing control interface assembly rather than using a separate dedicated button. The same armrest housing and structural elements are used to accommodate both the joystick/control interface and the emergency stop button, making the system more universal and reducing overall component count and cost.
2Device complexity
If an electronic latching system is implemented, then the system can be compact and cost-effective, but unintended reset actions (pulling, rotating, or pushing) may occur
Solution Approach 1:
The patent implements dynamic pressure detection by continuously monitoring the force applied to the button through the optocoupler mechanism. The system distinguishes between intentional activation (sustained pressure) and unintended actions (brief pulls, rotations, or pushes) by analyzing the duration and intensity of the detected force. This dynamic response allows the system to remain compact while preventing false triggering.
Solution Approach 2:
The patent uses feedback from the optocoupler to the microcontroller to verify button activation states. The system provides visual feedback through LEDs to confirm proper button engagement and uses this feedback loop to distinguish between intentional activation and unintended actions, ensuring reliable operation without requiring larger mechanical components.
3Reliability
If a separate reset button is added to prevent unintended reset, then safety is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent makes the emergency stop button self-resetting by designing it to automatically reset when the user releases the button or performs a specific motion sequence. The same button structure serves both as the activation mechanism and the reset mechanism, eliminating the need for a separate reset button and reducing overall system complexity while maintaining safety.
Solution Approach 2:
The patent implements a self-resetting mechanism where the system automatically resets the emergency stop function when it detects that the user has released the button or performed a predetermined motion. This self-service approach eliminates the need for additional reset components, keeping the system compact and simple while ensuring safety through automated functionality.
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
Provides a simple, safe, and reliable emergency stop system that prevents unintended use and integrates seamlessly into stairlift armrests, with fault detection capabilities.
Implementation Method 1
a light emitting device and a light receiving device, e.g., an LED and a photo resistor, i.e., an opto-coupler
Implementation Method 2
an electromagnetic signal interrupter, e.g., a movable vane
Data Source
AI summary
Disclosed is a safety system for a stairlift. The Safety system comprises a component for sending and receiving an electromagnetic signal that includes a light emitting device such as an LED and a light receiving device such as a photo resistor, an electromagnetic signal interrupter like a movable vane, a moveable activator, and a processor. The activator is configured to be moved by a user of the stairlift, which in turn causes the signal interrupter to interrupt a first electromagnetic signal.