Actuator Safety Mechanism Using Touch Element and Push Switch
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Solution Overview
Problem
Existing actuators lack a safety mechanism to prevent pinching injuries when a user's hand accidentally enters the moving path during operation, particularly in electric chairs and windows, as the motor can only be stopped when the nut reaches the limit switches at the ends of the retractable tube.
Innovation Solution
An actuator with a safety mechanism that includes a gearbox, motor, driven gear, transmission, retractable tube, and a push switch, where the transmission moves linearly to stop the motor when the touch element contacts the push switch, preventing accidental pinching by incorporating a guiding threaded rod and an elastic element to restore positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a motor and limit switches are used to control the retractable tube, then the actuator can achieve stretching and retracting functions, but it lacks safety mechanism to prevent pinching injuries when hand enters the moving path
Solution Approach 1:
The patent introduces a transmission mechanism with a touch element as an intermediary between the nut and the motor control system. When the nut moves during operation, the transmission mechanism allows the nut to continue moving while the touch element independently detects obstacles and triggers motor stoppage, resolving the contradiction by adding safety functionality through an intermediate component rather than directly modifying the motor control system
Solution Approach 2:
The patent segments the control function into two independent parts: the original limit switch control for end-position stopping, and a new touch element-based safety control for obstacle detection. This segmentation allows the safety mechanism to operate independently without interfering with the existing control system, thereby improving reliability while maintaining manageable structural complexity
2Ease of operation
If the motor stops only when the nut touches the limit switches at the ends, then the retractable tube can be controlled to stretch or retract, but pinching injuries occur when hand enters the moving path at middle position
Solution Approach 1:
The patent implements a feedback mechanism where the touch element continuously monitors the moving path for obstacles. When an obstacle is detected (hand entering the path), the touch element sends a feedback signal to stop the motor immediately, creating a closed-loop safety control system that responds to real-time conditions without complicating the overall operation
Solution Approach 2:
The transmission mechanism with the touch element is pre-positioned along the moving path of the nut. This preliminary arrangement ensures that the safety detection capability is already in place before operation begins, allowing immediate response to obstacles without requiring additional control steps or complex operational procedures
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 safety mechanism effectively stops the motor when the touch element activates the push switch, preventing pinching injuries and allowing for tighter closure of windows by ensuring the motor stops upon external force application, enhancing user safety.
Implementation Method 1
The guiding threaded rod drives a retractable tube connected thereto to make a stretching or retracting act
Implementation Method 2
By an arrangement of an elastic element, the bearing and the guiding threaded rod can be restored to their original positions
Data Source
AI summary
An actuator with a safety mechanism includes a gear box (10), a motor (20), a driven gear (30), a transmission (40), a retractable tube (50) and a push switch (60). The transmission (40) has a guiding threaded rod (41) and a touch element (42). When the retractable tube (50) is limited during moving, the transmission (40) will linearly move toward a direction of the retractable tube (50) and the motor (20) is stopped operating by touching the push switch (60) with the touch element (42). Thereby, an anti-pinch effect and increase of safety of using products can be accomplished.