Modular Reset Device for Limit Switch Safety
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Solution Overview
Problem
Existing limit switches lack flexibility in component orientation and interchangeability, leading to potential safety issues due to delayed reset activation and the need for specific components, which can result in accidental power restoration.
Innovation Solution
A modular reset device with interface means and a prismatic housing design that allows interchangeable fitting and orientation with various limit switches, ensuring simultaneous contact opening and reset activation, enhancing safety and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the reset device is integrated in the head with forced couplings between parts, then the switch can be manufactured as a complete unit, but the head can only be fitted with a specific contact holder and cannot be adjusted for different orientations
Solution Approach 1:
The reset device is separated from the head and contact holder assemblies, allowing each component to be independently manufactured and then assembled through interface means. This segmentation enables different contact holders to be fitted with the same head and reset device combination, improving interchangeability while maintaining manufacturing efficiency through standardized modules.
Solution Approach 2:
The interface means are designed with universal engagement features that allow the reset device to be coupled with different types of contact holders and heads. The interface includes positioning elements and engagement features that work across multiple component variations, enabling one reset device design to serve multiple switch configurations.
2Reliability
If the actuator has a long travel distance to trigger the reset device, then the reset device can be reliably activated, but contacts may open before the reset device is triggered allowing accidental power restoration
Solution Approach 1:
The reset device is positioned and configured to be triggered at the exact moment contacts open, rather than requiring a long actuator travel. The interface means and reset means are arranged so that the resetting action occurs preliminarily or simultaneously with contact opening, preventing any window for accidental power restoration while ensuring reliable activation.
Solution Approach 2:
The interface means act as an intermediary mechanism that couples the actuator, contacts, and reset device in a coordinated manner. This intermediary arrangement ensures that the actuator's motion is transmitted simultaneously to both the contacts and the reset device, synchronizing their activation without requiring excessive travel distance.
3Ease of operation
If the reset device is triggered after a great stroke of the actuator, then the reset device can be shaped to interact with the actuator, but the switching off and resetting occur at different times reducing safety
Solution Approach 1:
The reset device incorporates dynamic elements such as a snap-action mechanism that allows it to respond rapidly to actuator movement. The reset means can snap from one position to another quickly, ensuring that resetting occurs simultaneously with contact opening even though the physical structures are different. This dynamic response maintains safety timing while preserving ease of actuator interaction.
Data Source
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AI summary
The present invention generally finds application in the field of safety electric devices and relates to a reset device to be coupled to a limit switch (2), which comprises a modular housing (14), interface means (18) associated to said housing for removable coupling both to the head (4) and to the case (3) of the limit switch (2), reset means (13) at least partly accommodated in said housing (14) for controlled turning on and off of the limit switch (2). The reset means have such a shape as to interact with the actuator means of the switch to promote positive opening of the electric contacts substantially at the same time as the switch with which the device is associated is turned on/off.