Rotary Opening Limiter for Window Sash Security
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Solution Overview
Problem
Existing rotary opening limiting devices for windows and doors fail to securely fix the sash in a predetermined open position, especially for effective air exchange through gap ventilation, and provide questionable security against wind pressure.
Innovation Solution
A rotary opening limiting device with a pivotable holding arm and a coupling member that allows the sash to be securely fixed in various open positions by engaging locking pins with locking blocks, enabling adjustable ventilation gaps through handle operation, and providing enhanced security and ventilation control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sash is fixed in the fully open position (90° to the frame) using simple objects like rolled-up newspapers, then the device complexity is reduced, but the reliability of fixing is extremely questionable and security against wind pressure is poor
Solution Approach 1:
The holding arm is divided into multiple segments with different functions: a base part fixed to the frame, a holding arm portion that pivots to limit opening angles, and a coupling member that engages with the sash. This segmentation allows each part to perform its specific function while maintaining overall system reliability without excessive complexity
Solution Approach 2:
The coupling member acts as an intermediary between the holding arm and the sash. It transfers the limiting action from the holding arm to the sash through engagement with locking pins, providing reliable mechanical coupling that ensures secure fixing while maintaining a relatively simple overall structure
2Reliability
If a holding arm with coupling member is used to securely fix the sash in predetermined open positions, then the reliability of fixing is improved, but the device complexity increases
Solution Approach 1:
The holding arm assembly serves multiple functions: it limits the opening angle of the sash, provides secure fixing in predetermined positions, and enables gap ventilation. The coupling member simultaneously engages with different locking pins to provide both opening limitation and secure fixing. This multi-functionality reduces the need for separate devices, maintaining reasonable complexity while achieving reliable fixing
Solution Approach 2:
The holding arm is designed to pivot freely around a vertical axis, creating equipotential conditions where the arm can assume any angular position along its arc. This allows the sash to be securely fixed at any desired opening angle within the limited range, providing versatile and reliable fixing without requiring multiple discrete adjustment mechanisms
3Productivity
If the sash is opened completely to 90° position, then the ventilation gap is maximized, but the sash cannot be fixed in intermediate positions suitable for effective air exchange through gap ventilation
Solution Approach 1:
The holding arm provides dynamic opening limitation by allowing the sash to be opened to any angle within a predetermined range (up to but not exceeding 90°). The arm pivots with the sash movement and maintains engagement with the coupling member throughout the opening sequence, enabling flexible adaptation to different ventilation requirements while preventing excessive opening
Solution Approach 2:
The device changes the opening angle parameter of the sash from unrestricted (0-90° or more) to restricted (0 to predetermined angle ≤90°) through the mechanical action of the holding arm. This parameter modification enables effective gap ventilation at intermediate positions by preventing the sash from being opened too far, while still allowing sufficient opening for air exchange
4Reliability
If locking pins engage with locking blocks to secure the sash, then the security against wind pressure is improved, but the ease of operation decreases due to increased effort required
Solution Approach 1:
The locking pins are preliminarily positioned on the sash in fixed locations, and the coupling member is preliminarily positioned on the holding arm. When the sash is opened to the desired angle, the holding arm automatically guides the coupling member into engagement with the locking pins, which in turn engage with the locking blocks on the frame. This preliminary positioning reduces the effort required during operation, as the engagement process is guided rather than requiring precise manual alignment
Solution Approach 2:
The holding arm assembly performs self-service by automatically guiding the coupling member into engagement with the locking pins as the sash is opened. The mechanical geometry of the system ensures that the coupling member and locking pins align and engage automatically at the predetermined opening angle, reducing the operational effort required from the user while maintaining secure locking
Data Source
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AI summary
The device (1) has a base part (2) fixable at a blind frame of a door or a window, where a pivotably movable holding arm (3) is arranged at the base part. The holding arm cooperates with a coupling element (4) e.g. coupling bolt, that is arranged at a sash of the window or door, based on a handle controlled position of the coupling element. A catch position of the coupling element to the holding arm and a passing position of the coupling element to the holding arm exist in respective rotary opening restriction position of the handle and a rotary opening position of a handle (13) of the sash.