Door Actuator Mounting Bracket for Fire-Triggered Detachment

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Solution Overview

Problem

Existing door operators, particularly those used in fire doors, face challenges in ensuring reliable fastening while meeting safety requirements, especially in the event of a fire where flammable fluids like hydraulic oils can ignite.

Innovation Solution

A mounting bracket with a first and second mounting element connected via a connecting arrangement that separates under thermal stress, detaching the door operator from its mounting surface to prevent overheating and potential ignition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional mounting plate is used to attach the door operator, then reliable fastening is achieved, but the door operator may overheat and ignite in the event of a fire

Engineering Contradiction:
Improvefastening reliabilityVSAvoidthermal damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The mounting bracket is divided into two separable mounting elements (first mounting element and second mounting element) connected by a connecting arrangement. This segmentation allows the mounting elements to remain together during normal operation for reliable fastening, but separate under thermal stress to prevent heat transfer to the door operator during fire conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting arrangement incorporates a dynamic response to thermal conditions through the trigger element and drive element mechanism. Under normal temperatures, the connecting arrangement maintains a rigid connection for stable mounting. When exposed to fire-induced thermal stress, the trigger element activates the drive element, causing the connecting arrangement to dynamically transform from a connected state to a separated state, thereby protecting the door operator from thermal damage.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If the mounting bracket remains firmly attached during a fire, then mounting stability is maintained, but the door operator becomes excessively hot and may ignite

Engineering Contradiction:
Improvemounting stabilityVSAvoiddoor operator temperature
Core Design Contradiction:
Stability of the object's compositionVSTemperature

Solution Approach 1:

The connecting arrangement utilizes parameter changes in response to temperature conditions. The trigger element is designed to respond to thermal parameters (temperature increase during fire), which activates the drive element to change the physical state of the connecting arrangement from connected to separated. This parameter-based response ensures the mounting remains stable under normal temperature conditions but automatically detaches when temperature exceeds safe thresholds, preventing door operator ignition.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If a separating mechanism is added to the mounting bracket, then fire safety is improved, but device complexity increases

Engineering Contradiction:
Improvethermal protectionVSAvoidmounting bracket complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The separating mechanism is designed to be self-activating through the trigger element and drive element arrangement. The trigger element automatically responds to thermal stress conditions without requiring external control or intervention. When exposed to fire-induced heat, the trigger element autonomously activates the drive element, which then causes the mounting elements to separate. This self-service mechanism provides thermal protection functionality while minimizing the need for additional complex control systems.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The drive element acts as an intermediary mechanism between the trigger element (which detects thermal conditions) and the mounting elements (which need to separate). Rather than directly connecting the trigger to the mounting elements, the drive element serves as a mechanical mediator that translates the trigger's thermal response into the physical separation of mounting elements. This intermediary approach allows for a more manageable and modular design, reducing overall system complexity while achieving the desired fire safety function.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The mounting bracket effectively prevents the door operator from overheating and igniting by detaching it from the mounting surface during a fire, ensuring safety and reliable fastening.

Implementation Method 1

Under appropriate thermal stress, this connecting arrangement releases, so that the two mounting elements separate from one another

Methodology Applied
Scientific EffectThermal stress: Thermal Expansion

Data Source

PatentEP3926137B1Assembly bracket for a door actuator
Publication Date: 2025.08.06 DORMAKABA DEUT GMBH
  • EP3926137B1 patent drawingFigure 1
  • EP3926137B1 patent drawingFigure 2~3
  • EP3926137B1 patent drawingFigure 4~5A-A

AI summary

The invention relates to a mounting bracket (1) for a door actuator (102), comprising a first mounting element (3) and a second mounting element (4), wherein one of the two mounting elements (3) is designed for attachment to a mounting surface (101), in particular a door, frame or wall, and the other mounting element (4) is designed for receiving the door actuator (102), at least one connection arrangement (5) with a locking element (14) movably arranged on the first mounting element (3) and a thermally activated release element (15), wherein the locking element (14) is movable from a holding position to a release position, wherein the locking element (14) holds the second mounting element (4) in the holding position and releases the second mounting element (4) in the release position.and wherein the release element (15) releases the locking element (14) into the release position upon thermal activation and/or the release element (15) moves the locking element (14) into the release position upon thermal activation.