Motor Limit Switch Locking to Prevent Remote Reset Override

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Solution Overview

Problem

Existing limiting devices for motors allow operation beyond set limits and can be reset remotely, posing risks of damage to the drive system and components.

Innovation Solution

A dual-switch system with mechanically independent actuating elements and a mechanical lock mechanism that requires manual unlocking and visual inspection to manually unlock the limiting system, ensuring the operator to physically go to the drive system, and a mechanical lock mechanism that requires an electronic indication of a mechanical lock mechanism that requires an operator to manually unlock the limiting device, ensuring the system, and a mechanical lock mechanism that requires an mechanical lock mechanism that requires an operator to physically go to the drive system, and manually unlock the limiting system, ensuring the operator to visually inspect the drive system, and manually unlock the limiting system.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electronic limiting system with switches is used to stop motor operation at set limits, then the motor operation is controlled electronically, but the system can be reset from a distance allowing unintended operation beyond limits

Engineering Contradiction:

Improvelimit control reliabilityVSAvoidreset accessibility

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The limiting device is segmented into two independent systems: an electronic limiting system with switches for automated control, and a mechanical locking system with a lockable actuating element for physical security. This segmentation allows each system to fulfill its specific function - electronic control for automated operation and mechanical lock for secure manual intervention only when physically present

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The actuating element serves as an intermediary component that connects both the electronic and mechanical systems. It is driven by the motor through the transmission to actuate the electronic switches, and simultaneously can be mechanically locked to prevent any further action. This dual-role intermediary enables integration of both limiting approaches

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If a single switch system is used for limiting motor movement, then the device complexity is low, but the motor may run beyond the set limit due to reset issues

Engineering Contradiction:

Improvelimiting system complexityVSAvoidlimit enforcement reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The mechanical lock is designed to engage the actuating element in advance at the limit position, preventing any possibility of the motor running beyond the set limit. By taking preliminary mechanical action to block the actuating element before electronic reset can occur, the system ensures reliable limit enforcement without requiring complex multi-stage electronic control

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentEP3327740B1Device for limiting, and drive system comprising a device for limiting

Publication Date: 2025.12.24 RIDDER BEHEER BV

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AI summary

The invention provides a device for limiting a movement of a member driven by a motor, comprising at least one switch functionally couplable to the motor, at least one movable actuating element, driven by the member driven by the motor and coacting with the at least one switch, and a mechanical lock for engaging said actuating element for mechanically locking said actuating element when it is at or past at least one set limit position.