Window Actuator Safety Device with Thermal Locking
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Solution Overview
Problem
Conventional window unit actuators fail to ensure complete opening and prevent closing during high-temperature fires due to softening of plastic components, and existing locking devices are bulky, reducing compactness and requiring external activation.
Innovation Solution
A safety device with a temperature-sensitive yielding block and locking element that transitions to an operating configuration at a predefined temperature, allowing complete window opening while preventing closure by interfering with the actuation member's retraction without obstructing extension, thus ensuring reliability and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional locking device is used to prevent window closing at high temperatures, then reliability is improved, but the actuator volume increases and compactness is reduced
Solution Approach 1:
The locking function is merged with the existing actuation member (chain or toothed rod) by providing locking elements that engage directly with the actuation member teeth. This integration eliminates the need for a separate bulky locking device, maintaining compact actuator volume while ensuring window opening stability at high temperatures through automatic locking engagement.
Solution Approach 2:
The locking elements are nested within the existing actuator structure, with locking elements positioned to engage the actuation member teeth within the same spatial envelope as the motor and gear. This nesting approach allows the locking function to be housed inside the existing actuator casing without increasing external dimensions.
2Reliability
If a locking device is positioned between the casing opening and operating device, then window opening stability is improved, but the working travel of the actuation member is reduced
Solution Approach 1:
The locking elements engage the actuation member in a radial direction (perpendicular to the actuation member's longitudinal axis) rather than along its length. This dimensional change allows the locking function to be implemented without consuming additional linear travel distance of the actuation member, preserving full working travel while ensuring stability.
3Ease of manufacture
If plastic components are used in the actuator, then ease of manufacture is improved, but temperature resistance is reduced at high temperatures
Solution Approach 1:
Different material qualities are applied to different components based on their functional requirements. Plastic materials are used for the motor housing, gear, and other non-critical components where ease of manufacture is important. Metal materials are used specifically for the locking elements and actuation member where high-temperature strength and stability are critical. This local differentiation maintains manufacturing simplicity while ensuring heat resistance where needed.
Solution Approach 2:
The actuator employs a composite material strategy combining plastic and metal components. The plastic gear and housing provide ease of manufacture and cost-effectiveness, while metal locking elements and actuation members provide high-temperature structural integrity. This composite approach leverages the advantages of both material types in their respective functional zones.
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 ensures complete window opening during fires and prevents closure at high temperatures, enhancing reliability and safety without external activation, while maintaining a compact design and ease of installation.
Implementation Method 1
a yielding block 16 fixed to the base 13 so as to prevent the locking element 14 from reaching the operating configuration, wherein the yielding block 16 is sensitive to a temperature so as to yield when a predefined temperature is exceeded
Data Source
Figure 1~2b
Figure 3~4
AI summary
Safety device (10) for an actuator (100) for a window unit where the actuator (100) comprises a frame (11), an actuation member (12) and an operating device fixed to the frame (11) and coupled to the actuation member (12). In an opening configuration of the window unit the actuation member (12) is extended and in a closing configuration it is retracted. The safety device (10) comprises: - a base (13), - a locking element (14) movable between a rest configuration and an operating configuration; - elastic means (15) for forcing the locking element (14) into the operating configuration; - a yielding block (16) for retaining the locking element (14). The yielding block (16), when a predefined temperature is reached, yields so as to allow the locking element (14) to reach the operating configuration and interfere with the actuation member (12) so as to oppose the retraction thereof with respect to the frame 11 and allow the extension thereof.