Door Actuator Bracket with Shape Memory Thermal Release

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Solution Overview

Problem

Existing assembly consoles for door operators, especially in fire protection doors, face challenges in ensuring operational attachment while meeting safety requirements, particularly in preventing overheating and inflammation of combustible fluids during fires.

Innovation Solution

A modular assembly console with interconnected assembly elements, utilizing shape memory materials to create a thermal-activated connection arrangement that loosens and separates the elements upon reaching a specific temperature, thereby safely detaching the door operator from its assembly area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional mounting plate is used to attach the door operator, then the door operator is securely fastened to the mounting surface, but the door operator becomes excessively hot during fire and the fluid may escape and ignite

Engineering Contradiction:
Improvesecure fastening of door operatorVSAvoidoverheating and fluid ignition risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The mounting bracket is divided into two separate mounting elements (first mounting element and second mounting element) that are connected via a connecting arrangement. This segmentation allows the system to maintain secure attachment during normal operation while enabling separation when thermal activation occurs, thus resolving the contradiction between reliable fastening and fire safety.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting arrangement incorporates a shape memory assembly that dynamically changes the state of connection between mounting elements based on temperature. At normal temperatures, the connecting arrangement maintains a holding position for secure attachment. During fire, thermal activation causes the connecting arrangement to move to a release position, dynamically transitioning from attached to detached state to prevent fluid ignition.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the door operator is securely attached during normal operation, then it performs its function reliably, but it cannot detach automatically during fire to prevent fluid escape and ignition

Engineering Contradiction:
Improveoperational reliability of door operatorVSAvoidfluid escape and ignition during fire
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The connecting arrangement utilizes temperature as a critical parameter to control the connection state. The shape memory assembly is designed with specific thermal activation characteristics that cause it to change its mechanical properties at elevated temperatures. This parameter-based control allows the system to maintain connection during normal operation (low temperature) and automatically detach during fire (high temperature), preventing fluid escape and ignition.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The harmful effect of heat during fire is converted into a beneficial trigger for detachment. The thermal energy that would otherwise contribute to overheating and fluid ignition is instead used to activate the shape memory assembly, which automatically releases the connecting arrangement and detaches the door operator from the mounting surface, preventing the harmful outcome.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Object-affected harmful factors

If a shape memory assembly is integrated into the mounting bracket for thermal activation, then automatic detachment during fire is achieved, but the device complexity increases

Engineering Contradiction:
Improveprevention of fluid ignitionVSAvoidmounting bracket structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The shape memory assembly serves multiple functions within the mounting bracket system: it acts as both a connection maintaining element during normal operation and a thermal activation trigger for detachment during fire. This multi-functionality reduces the need for separate dedicated components, thereby limiting the increase in device complexity while achieving the fire safety function.

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

Solution Approach 2:

The shape memory assembly is a self-activating component that automatically responds to thermal conditions without requiring external control systems, sensors, or power sources. The connecting arrangement self-regulates the connection state based on temperature, eliminating the need for complex control circuitry or manual intervention, thus achieving fire safety with minimal added complexity.

Inventive Principle:
Principle #25Self-service

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 solution effectively prevents overheating and potential inflammation of fluids in door operators by ensuring safe detachment during elevated temperatures, thus enhancing fire safety and operational reliability.

Implementation Method 1

The shape memory material is, in particular, a special metal that can exist in two different crystal structures (e.g., austenite and martensite). The shape memory assembly is arranged and configured in the mounting bracket such that, upon thermal activation, it moves the connecting assembly into the release position.

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 2

Thermal activation occurs, in particular, in a temperature range of 90°C to 200°C. In particular, the shape memory assembly is designed such that activation occurs at a temperature appropriate to prevent the fluid from escaping from the door operator and subsequently igniting the fluid.

Methodology Applied
Scientific EffectThermal activation: Phase Change

Implementation Method 3

The shape memory element changes its length upon thermal activation; in particular, it shortens. As a result, a force, in particular a tensile force, can be exerted on an element of the connecting arrangement by thermal activation of the shape memory element.

Methodology Applied
Scientific EffectThermal expansion/contraction: Thermal Expansion

Data Source

PatentEP4012141B1Assembly bracket for a door actuator
Publication Date: 2025.03.19 DORMAKABA DEUT GMBH
  • EP4012141B1 patent drawingFigure 1
  • EP4012141B1 patent drawingFigure 2~3
  • EP4012141B1 patent drawingFigure 4

AI summary

The invention relates to a mounting bracket (1) for a door actuator (102), comprising at least 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 connecting arrangement (5) which holds the two mounting elements (3, 4) together in a holding position and does not hold the two mounting elements (3, 4) together in a release position, and at least one shape memory arrangement (20) with a shape memory element (21) made of shape memory material, wherein the shape memory arrangement (20) moves the connecting arrangement (5) into the release position upon thermal activation.