Segmented Contact Strip for High-Speed Safety Door Locking

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Solution Overview

Problem

Existing door locking devices for machine tools and similar applications face challenges in achieving high movement speed while ensuring reliable and safe locking, as longer contact strips increase inertial mass, requiring significant acceleration forces and potentially risking injury or jamming.

Innovation Solution

The contact strip is divided into spatially separate sections with a shaft connecting each section to the locking member, allowing only one section to move at a time, reducing inertial mass and ensuring reliable locking through independent triggering and operational connection via cams and counter-cams, enabling high-speed door movement and quick locking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a long contact strip is used to ensure complete coverage for safety, then the safety function is improved, but the inertial mass increases requiring significant acceleration forces

Engineering Contradiction:
Improvesafety functionVSAvoidinertial mass of contact strip
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The contact strip is divided into multiple separate sections (first contact section, second contact section, etc.) that are spatially distributed along the door edge. Each section can be triggered independently and has significantly reduced mass compared to a continuous long contact strip, thereby reducing the inertial mass that must be accelerated while maintaining comprehensive safety coverage.

Inventive Principle:
Principle #1Segmentation

2Reliability

If a long contact strip is used to cover the entire door edge, then the safety coverage is improved, but the door movement speed decreases due to higher acceleration forces required

Engineering Contradiction:
Improvesafety coverageVSAvoiddoor movement speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The contact strip is segmented into multiple independent sections that can be triggered separately. When the door closes, only the necessary sections are activated rather than the entire contact strip, significantly reducing the mass that needs to be accelerated and enabling higher door movement speeds while maintaining safety coverage.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact strip sections are triggered in a sequential or selective manner during the door closing process, rather than all at once. This periodic or selective activation reduces the instantaneous acceleration forces required, allowing the door to maintain high movement speed while still providing comprehensive safety monitoring.

Inventive Principle:
Principle #19Periodic action

3Speed

If the contact strip sections are independently triggered, then the acceleration forces required are reduced, but the device complexity increases due to additional shaft and cam mechanisms

Engineering Contradiction:
Improvedoor movement speedVSAvoidshaft and cam mechanism complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The shaft serves multiple functions: it connects all contact strip sections, provides the cam mechanism for triggering, and transmits the triggering force to the locking member. This multi-functionality reduces the need for separate mechanisms for each function, thereby limiting the increase in device complexity despite the segmented design.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The shaft integrates the connection function, triggering mechanism (via cams), and force transmission function into a single component. By merging these functions into one element rather than using separate components for each, the overall device complexity is kept manageable while still achieving independent triggering of contact strip sections.

Inventive Principle:
Principle #5Merging (Combining)

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

This design allows for high-speed door operation with reduced acceleration forces, ensuring rapid locking and enhanced safety by distributing the inertial mass and providing a reliable safety function, thus minimizing the risk of injury or jamming.

Implementation Method 1

a shaft is provided between the sections of the contact strip and the locking member, which is in a non-positive or positive operative connection with each of the sections of the contact strip and the locking member

Methodology Applied
Scientific EffectCam and counter-cam mechanism: Cam

Data Source

PatentEP3106738B1Device for moving and fastening a door
Publication Date: 2017.10.11 STRASSER MASCHENBAU
  • EP3106738B1 patent drawingFigure 1
  • EP3106738B1 patent drawingFigure 2
  • EP3106738B1 patent drawingFigure 3

AI summary

In a device (1) for moving and locking a door (2), in particular a safety door arranged in front of a work area to be secured, comprising at least one profile rail (3, 4) by which the door (2) is guided, a servo device (11) adjustable to the door (2), a locking element (21) arranged on the door (2) and pivotably mounted to a limited extent, which engages a guide column (7) running parallel to the profile rails (3, 4), and a contact strip arranged at the lower edge of the door (2), which is mechanically coupled to the locking element and by which automatic locking of the door (2) to lock the door (2) upon activation of the contact strip (8) can be achieved, the highest possible approach speed should be adjustable for the door (2) of the device (1).This is achieved by forming the contact strip (8) from several spatially separated subsections, and by providing a shaft (13) between the subsections of the contact strip (12) and the locking element, which is in a force-locking or form-locking operative connection with each of the subsections of the contact strip (12) and the locking element.