Scissor Hinge Snap-In Assembly for Window Sash
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Solution Overview
Problem
Existing scissor-stay hinges for windows and doors are difficult to assemble, especially for large and heavy sashes, due to the complexity of aligning hinge pins and the need for manual holding of the sash during assembly.
Innovation Solution
Designing the scissor arm as a pre-assemblable unit with snap-in connections for the joint bolts and receptacles, allowing for easy mounting on the sash and frame, and incorporating run-up bevels and locking heads to simplify and automate the assembly process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional hinge pins are used that require manual alignment and holding during assembly, then the connection strength is sufficient, but the assembly process becomes very laborious and time-consuming
Solution Approach 1:
The hinge pins are pre-assembled with the scissor arm in a first pre-assemblable assembly, and the receptacles are pre-positioned on the wing-side fitting part. This preliminary preparation eliminates the need for manual alignment during final assembly, as components are designed to fit together automatically when the sash is pressed into the frame.
Solution Approach 2:
The snap-in connection design allows the hinge pins to self-align and self-lock into the receptacles through the closing movement of the sash. The locking connections engage automatically during the pressing-in process, eliminating the need for manual holding or positioning by multiple workers.
2Ease of manufacture
If multiple components are used to create a two-piece fitting part for pre-assembly, then the assembly process can be simplified, but the device complexity increases due to the large number of components
Solution Approach 1:
The invention merges the hinge pin and scissor arm into a single pre-assembled unit, and combines the receptacle mounting features directly into the wing-side fitting part. This reduction to essential components eliminates the need for separate two-piece fitting parts while maintaining the benefits of pre-assembly.
3Reliability
If hinge pins are pressed from above into receptacles during assembly, then the connection is secure, but the sash must be held in a specific position making assembly laborious
Solution Approach 1:
Instead of pressing hinge pins from above into receptacles while holding the sash in position, the invention inverts the process by designing the hinge pins to be pre-assembled on the scissor arm and the receptacles to be integrated into the wing-side fitting part. The secure connection is achieved through snap-in locking that engages automatically during the closing movement.
4Extent of automation
If locking connections are designed to engage during sash closing movement, then automation becomes possible and assembly is simplified, but the joining direction must be precisely aligned with the frame
Solution Approach 1:
The locking connections are designed with specific local features on the hinge pins and receptacles that ensure proper alignment and engagement. The run-up bevels and locking geometries are precisely formed in critical areas to guide the pins into the receptacles during closing movement, while other areas maintain design flexibility.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A scissor hinge (3) of a tilt-and-turn window fitting has locking connections (18, 19) for connecting a scissor arm (5) to a sash-side fitting part (7) and to a link arm (8). The joining directions of the locking connections (18, 19) are aligned with the closing direction of a sash (2) of the window. The locking connections (18, 19) have pivot pins (14, 15) that snap into receptacles (16, 17). One of the locking connections (18, 19) is secured with a locking head (24).