Safety Guard Interlock Release State Detection and Reset

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Solution Overview

Problem

Interlocking devices for movable safety guards often require tedious failure analysis after the additional release mechanism is activated, as the control system cannot distinguish between blockages caused by the release mechanism and other control failures, leading to difficulties in resuming normal operation.

Innovation Solution

An interlocking device with a locking unit, electric mover, additional release unit, sensor device, and evaluation unit that outputs distinct signals to differentiate between normal and additional release positions, allowing for easier troubleshooting and maintenance by detecting the activation of the auxiliary release mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If an additional release mechanism is added to the interlocking device, then the ease of operation is improved (manual release capability), but the device complexity increases and troubleshooting difficulty increases

Engineering Contradiction:
Improvemanual release capabilityVSAvoidinterlocking device structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

A sensor device is introduced as an intermediary element that detects the position of the locking unit and generates position signals. This mediator provides the control system with information about the interlocking device's state without requiring direct monitoring, thus adding minimal complexity while enabling automated troubleshooting and reset capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensor device provides feedback signals to the control system about the locking unit's position. This feedback mechanism allows the control system to automatically determine whether a manual reset is needed after activation of the additional release mechanism, reducing troubleshooting complexity and improving ease of operation.

Inventive Principle:
Principle #23Feedback

2Reliability

If the control system monitors the interlocking device state, then the reliability is improved, but the loss of time increases due to tedious failure analysis

Engineering Contradiction:
Improvesafety function monitoringVSAvoidfailure analysis time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The sensor device continuously monitors the position of the locking unit and provides position signals to the control system in advance. When the additional release mechanism is activated, the control system already has the necessary information to determine the device state, eliminating the need for time-consuming failure analysis and enabling immediate resumption of normal operation.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If manual reset is required after additional release activation, then the reliability is improved (preventing unintended locking), but the ease of operation worsens (reset complexity)

Engineering Contradiction:
Improvelocking function safetyVSAvoidreset procedure
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control system automatically determines whether a manual reset is needed by evaluating the position signal from the sensor device. This self-service capability eliminates the need for operators to perform tedious failure analysis, while still maintaining the required manual reset function for reliability. The system serves itself by making the reset decision based on sensor feedback.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3667150B1Interlocking device
Publication Date: 2021.01.27 SICK AG
  • EP3667150B1 patent drawingFigure 1
  • EP3667150B1 patent drawingFigure 2
  • EP3667150B1 patent drawingFigure 3

AI summary

An interlocking device for locking a movable safety guard has a locking unit, an electric mover, an additional release unit, a sensor device and an evaluation unit. The locking unit is movable between a locking position for interlocking the movable safety guard and a release position for releasing the movable safety guard and the mover is configured to move the locking unit between the locking position and the release position. The additional release unit is movable from a neutral position into an additional release position to move the locking unit from the locking position into the release position. The sensor device is configured to detect a position of the locking unit and a position of the additional release unit. The evaluation unit is configured to output a locking signal when the locking unit is in the locking position, a normal release signal when the locking unit has been moved into the release positon by the electric mover, and an additional release signal when the locking unit has been moved into the release position by the additional release unit.