Safety Cabinet Spring Door Locking Mechanism

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Solution Overview

Problem

Existing safety cabinet designs primarily rely on automatic door closing during high temperatures or fires, failing to provide a convincing solution for automatic door closure in normal operational cases.

Innovation Solution

A safety cabinet with a spring element connected via a push/pull rod to a connecting element, allowing for manual or motorized blocking and unblocking of the swing door, ensuring automatic closure by releasing the spring element from end stops, utilizing a gas pressure spring with a snap lock mechanism that can be mechanically, hydraulically, pneumatically, or electrically released, and an additional scroll spring for fire scenarios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a spring unit is constantly tensioned during normal operation, then automatic door closing is achieved, but the device complexity increases and energy consumption rises

Engineering Contradiction:
Improveautomatic door closingVSAvoiddevice complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The spring element is pre-tensioned during door opening and stored in a blocked position, ready to automatically close the door when released. This preliminary action eliminates the need for continuous energy input while maintaining automatic closing capability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The blocking function is extracted as a separate mechanism (blocking element) that can independently engage or disengage the spring element. This separation allows the spring unit to remain simple during normal operation while providing automatic closing only when needed.

Inventive Principle:
Principle #2Taking out (Extraction)

2Extent of automation

If a locking device in the form of a door closer is used, then automatic door closing is achieved, but the device complexity and cost increase

Engineering Contradiction:
Improveautomatic door closingVSAvoiddevice complexity
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The spring element serves dual functions: it provides the closing force and simultaneously acts as the locking mechanism when blocked. This self-service approach eliminates the need for separate door closer devices, reducing complexity and cost.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The spring element is designed to perform multiple functions: it provides closing force during normal operation, acts as a latch when blocked, and enables automatic closing when released. This multi-functionality replaces what would traditionally require multiple separate components.

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

3Ease of operation

If the spring element is blocked in a predetermined open position, then the door can be held open, but the ease of operation decreases due to additional blocking mechanisms

Engineering Contradiction:
Improvedoor positioning flexibilityVSAvoiddevice complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The blocking element acts as an intermediary between the operator's intent and the spring element's force. It provides a simple mechanical interface that can engage or disengage to hold or release the door, without requiring complex control systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of using a complex mechanism to actively close the door, the invention uses a simple blocking element that passively holds the door open. Automatic closing is achieved by simply removing the block, inverting the traditional approach where active mechanisms drive door movement.

Inventive Principle:
Principle #13The other way round (Inversion)

4Extent of automation

If the spring element is designed to be releasable from end stops, then automatic door closing is enabled, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveautomatic door closingVSAvoidmanufacturing precision
Core Design Contradiction:
Extent of automationVSManufacturing precision

Solution Approach 1:

The spring element transitions between static blocked positions and dynamic movement. The guiding element provides dynamic constraints that allow the spring to move freely in the desired direction while maintaining simple geometric relationships, reducing precision requirements compared to fully constrained mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The blocking and guiding functions are segmented into separate elements: the blocking element engages/disengages the spring, while the guiding element provides directional constraints. This segmentation allows each component to be manufactured with simpler tolerances rather than requiring a single complex component with multiple precision features.

Inventive Principle:
Principle #1Segmentation

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

Enables automatic door closure in normal operation without external energy sources, ensuring the cabinet remains energy self-sufficient and secure, with the option to manually or automatically close the door, and guarantees closure during fires through the scroll spring mechanism.

Implementation Method 1

a spring element (8a, 8b), which can be blocked in at least one predetermined open position of the swing door and which acts on the swing door at least in the direction of the closed position

Methodology Applied
Scientific EffectSpring element: Spring

Implementation Method 2

the spring element is a gas pressure spring

Methodology Applied
Scientific EffectGas pressure spring: Gas Compressor

Implementation Method 3

The piston can be fixed using the snap lock

Methodology Applied
Scientific EffectSnap lock mechanism: Mechanical Fastener

Implementation Method 4

In addition, a scroll spring is provided

Methodology Applied
Scientific EffectScroll spring: Spring

Data Source

PatentEP2603657B1Cabinet, in particular safety cabinet
Publication Date: 2020.01.22 DUEPERTHAL SICHERHEITSTECHNIK GMBH & CO KG
  • EP2603657B1 patent drawingFigure 1
  • EP2603657B1 patent drawingFigure 2
  • EP2603657B1 patent drawingFigure 3

AI summary

The present invention relates to a cabinet, in particular a safety cabinet. Said cabinet is equipped with at least one swing-leaf door (3) and with a spring element (8a, 8b), which is connected to the swing-leaf door (3) and acts upon the latter at least in the direction of the closed position. According to the invention, the spring element (8a, 8b) is lockable in at least one predefined open position of the swing-leaf door (3) and, after the locking has been removed by an operator, serves for automatic closing of the door.