Sacrificial Lock Cylinder Connection for Fire Safety
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Solution Overview
Problem
Fire protection doors with existing locking devices face challenges in preventing the spread of fire due to heat conduction through the locking mechanism, which can cause electronic components and batteries to overheat and catch fire, potentially spreading flames.
Innovation Solution
Incorporating a sacrificial connection element with a low melting point, such as soft solder, that separates the electromechanical actuating element from the lock cylinder at a specific temperature, preventing heat conduction and allowing the element to fall off, thus preventing the spread of fire.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuating element is firmly connected to the cylinder shaft to ensure reliable operation, then the operational reliability is improved, but the fire resistance deteriorates due to heat conduction
Solution Approach 1:
The connecting unit is divided into a permanent connecting element (for reliable operation) and a sacrificial connecting element (for fire protection). The sacrificial element is designed to melt at a critical temperature, segmenting the thermal pathway while preserving the mechanical connection during normal use.
Solution Approach 2:
The sacrificial connecting element acts as an intermediary between the actuating element and the cylinder shaft. It provides a thermal barrier that melts under fire conditions, preventing heat conduction while maintaining mechanical integrity during normal operation.
2Strength
If a strong connection is used between the actuating element and cylinder shaft, then the mechanical strength is improved, but the thermal insulation deteriorates
Solution Approach 1:
The connection is segmented into two functional parts: a permanent connecting element that provides mechanical strength, and a sacrificial connecting element that provides thermal insulation by creating a discontinuous thermal pathway through its low melting point material.
Solution Approach 2:
The connecting unit uses composite construction combining different materials with complementary properties - one material optimized for mechanical strength and another for thermal protection - to achieve both strong connection and thermal insulation simultaneously.
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 the spread of fire by thermally and spatially isolating the actuating element from the lock cylinder, reducing the risk of electronic components and batteries igniting and causing further fire hazards.
Implementation Method 1
the sacrificial connecting element (54) is designed to separate the actuating element (32) from the cylinder shaft (26) at a critical temperature... the sacrificial connecting element be designed to melt when it reaches its critical temperature
Implementation Method 2
preventing heat conduction into the actuator via the lock cylinder... thermally and spatially isolating the actuating element from the lock cylinder
Implementation Method 3
the actuating element be designed to fall off the cylinder shaft when it is separated from the cylinder shaft by the sacrificial connecting element
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a locking device for a door (10a), in particular for a fire door, with a locking cylinder (22a; 22b; 22c; 22d; 22e) which has at least one cylinder shaft (26a; 26b; 26c; 26d; 26e), with at least one first electromechanical actuating element (32a; 32b; 32c; 32d; 32e) which comprises at least one electronic unit (38a; 38b; 38c; 38d; 38e) and/or a battery unit (40a; 40b; 40c; 40d; 40e) and in a normal operating state is connected to the cylinder shaft (26a; 26b; 26c; 26d; 26e) of the locking cylinder (22a; 22b; 22c; 22d; 22e). It is proposed that the connecting unit (48a; 48b; 48c; 48d; 48e) has at least one sacrificial connecting element (54a; 54b; 68c, 70c; 54d; 54e) which is designed to disconnect the actuating element (32a; 32b; 32c; 32d; 32e) from the cylinder shaft (26a; 26b; 26c; 26d; 26e) at a limit temperature.