Security Cabinet Spring Decoupling for Fatigue Reduction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

The dual functionality of scroll springs in safety cabinets, which ensures both automatic closure and fire locking, leads to fatigue and unreliable operation due to constant stress, posing a serious safety concern.

Innovation Solution

The spring unit is functionally decoupled from the connecting element during normal operation, maintaining a constant tensioned position and only engaging during automatic closing, such as in a fire scenario, to prevent fatigue and ensure reliable function.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the scroll spring is integrated into the guide for the connecting element, then the spring unit can ensure automatic closure and fire locking, but the spring unit experiences constant stress and fatigue during normal operation

Engineering Contradiction:
Improvespring unit reliabilityVSAvoidspring unit stress
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The spring unit is segmented into a first region (constant tension region) and a second region (variable tension region). The first region maintains constant tension independent of door position, while the second region engages only when needed for automatic closure. This segmentation allows the spring to provide reliable force without experiencing constant stress during normal operation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring unit's tension characteristic is made dynamic through the transition from constant tension in the first region to variable tension in the second region. The constant tension region ensures reliable spring function, while the variable tension region engages only during automatic closure operations, reducing overall stress and fatigue.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the scroll spring follows every movement of the connecting element, then the spring unit can maintain connection, but the spring unit shows signs of fatigue and becomes unreliable

Engineering Contradiction:
Improvespring unit connection stabilityVSAvoidspring unit reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The spring unit is divided into two functional regions: the first region maintains stable connection through constant tension regardless of connecting element position, while the second region provides variable tension only during automatic closure. This segmentation preserves connection stability without the fatigue that would result from the spring following every movement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first region of the spring unit acts as an intermediary element that decouples the constant tension requirement from the variable movement of the connecting element. It provides stable connection while allowing the second region to engage only when needed, preventing fatigue accumulation.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the spring unit is used during normal opening and closing, then the spring unit can maintain connection, but the spring unit experiences stress and wear

Engineering Contradiction:
Improvedoor operationVSAvoidspring unit stress
Core Design Contradiction:
Ease of operationVSStress or pressure

Solution Approach 1:

The spring unit is segmented such that the first region operates independently during normal door movement, maintaining constant tension without stress. The second region engages only during automatic closure operations. This allows easy manual operation while preventing spring stress and wear during normal use.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The variable tension function is extracted from the constant tension spring unit. The first region provides constant tension for reliable connection, while the second region (with variable tension) is extracted to engage only during automatic closure, separating the functions to eliminate unnecessary stress during normal operation.

Inventive Principle:
Principle #2Taking out (Extraction)

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 ensures the spring unit remains functional and reliable, with no stress during normal opening and closing, allowing for one-handed operation and guaranteed automatic closure in emergency situations, enhancing safety and ease of monitoring.

Implementation Method 1

a spring unit (8, 9, 10) which holds both swing doors (3) in at least automatic closing operation applied force in the direction of its closed position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2017420B1Cabinet, in particular security cabinet
Publication Date: 2009.10.07 DUEPERTHAL SICHERHEITSTECHNIK GMBH & CO KG
  • EP2017420B1 patent drawingFigure 1
  • EP2017420B1 patent drawingFigure 2~3

AI summary

The cabinet has rotary wing doors (3), which are attached together to a connecting element (5) movable in a guide (7) and a spring unit e.g. scroll spring (8), charging the wing door towards a closing position in closing operation by an action of force. The spring unit is decoupled functionally from the connecting element in normal operation and acts only in closing operation. The spring unit constantly retains strained position during normal operation. The spring unit is arranged parallel to the guide of the connecting element.