Scissor Fitting Asymmetric Toothing for Sash Alignment
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Solution Overview
Problem
The existing scissor fitting arrangements for windows and doors lack an efficient mechanism for automatic adjustment of the effective length, leading to misalignment and increased mechanical stress due to gravitational deformation and wear, which can result in improper sash alignment and increased wear on the fitting components.
Innovation Solution
The scissor fitting incorporates a toothing and counter-toothing mechanism directly formed on the carrying handle and scissor arm, allowing only shortening of the effective length, preventing lengthening and enabling automatic adjustment to maintain correct alignment, with no additional separate elements required for direction-dependent blocking or releasing, ensuring stable and reliable mounting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the effective length of the scissor fitting is fixed, then the structure is simple and stable, but the sash alignment deteriorates due to gravitational deformation and wear over time
Solution Approach 1:
The scissor fitting incorporates a dynamic adjustment mechanism where the scissor arm can automatically change its effective length through the toothing-counter-toothing engagement system. This allows the fitting to adapt to gravitational deformation and wear over time, maintaining proper sash alignment without requiring manual intervention or complex adjustment procedures.
Solution Approach 2:
The fitting arrangement enables self-adjustment through the gravitational force acting on the sash. When the sash sags due to gravity or wear, the toothing and counter-toothing mechanism automatically engages to shorten the effective length of the scissor arm, correcting the alignment without external intervention. The system uses the gravitational load itself as the driving force for adjustment.
2Manufacturing precision
If the effective length can be adjusted, then the sash alignment is maintained, but the mechanism becomes more complex with additional components
Solution Approach 1:
The adjustment mechanism is merged into the existing scissor arm structure. The toothing is formed directly on the scissor arm, and the counter-toothing is integrated with the adjustment component, eliminating the need for separate adjustment mechanisms. This combining of functions maintains manufacturing precision while minimizing structural complexity.
Solution Approach 2:
The toothing and counter-toothing are designed with asymmetric profiles that allow unidirectional adjustment. The teeth are shaped such that they can engage to shorten the effective length but prevent lengthening, providing precise alignment control through asymmetric geometric constraints rather than complex bidirectional mechanisms.
3Length of moving object
If the scissor arm can be lengthened, then the effective length is increased, but the structural stability and load-bearing capacity are reduced
Solution Approach 1:
Instead of allowing the scissor arm to be lengthened when needed, the mechanism is inverted to automatically shorten the effective length when the sash sags. The toothing-counter-toothing system is designed to engage in the shortening direction, converting the problematic sagging motion into a corrective action that maintains structural stability while achieving the desired alignment.
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
This solution allows for automatic correction of the effective length, maintaining proper sash alignment and reducing mechanical stress, ensuring the sash can swing correctly and preventing wear on the fitting components, while being structurally simple and cost-effective.
Implementation Method 1
a displacement of the carrying handle that increases the effective length is blocked relative to the scissor arm and a displacement of the carrying handle that reduces the effective length is permitted relative to the scissor arm
Data Source
Figure 1~5
AI summary
A hardware arrangement for a window, door, or the like comprises a scissor hinge designed to pivot a sash of the window or door onto a frame of the window or door. The scissor hinge includes a frame-side support bracket and a sash-side scissor arm, which overlap and are slid relative to each other along a direction of movement to adjust the effective length of the scissor hinge. The support bracket has teeth formed directly on it, and the scissor arm has corresponding teeth formed directly on it. The teeth and the corresponding teeth are designed to engage in such a way that any movement of the support bracket relative to the scissor arm that would increase the effective length is prevented, while movement of the support bracket relative to the scissor arm that would decrease the effective length is permitted.