Double Door Latch Assembly Spring Actuation
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Solution Overview
Problem
The existing latch assembly for double doors often experiences operational difficulties due to loosening of the faceplate, which prevents smooth opening of the follower door, as it fails to reliably maintain the latch in the disengaged position.
Innovation Solution
A latch assembly with a base, movable member, and pressing board that allows the latch to transition between latching and unlatching positions without relying on a faceplate, ensuring smooth operation and reliable locking of the follower door.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a faceplate is used to press against the latch for disengagement, then the latch can be moved from latching to unlatching position, but the faceplate becomes loosened over time preventing smooth operation
Solution Approach 1:
The patent removes the faceplate component from the system entirely. Instead of using a separate faceplate mounted to the door frame to press against the latch, the invention integrates the pressing function directly into the latch assembly through the spring mechanism that automatically pushes the latch between engagement and disengagement positions.
Solution Approach 2:
The latch assembly becomes self-regulating through the integrated spring mechanism. The spring automatically maintains the latch in the appropriate position (engaged or disengaged) based on door movement, eliminating the need for external faceplate intervention and ensuring reliable operation without loosening issues.
2Ease of operation
If the faceplate is mounted to the door frame to actuate the latch, then the latch can be disengaged, but the faceplate moves to a position preventing latch disengagement
Solution Approach 1:
The faceplate is completely removed from the system. The patent replaces the faceplate-based actuation mechanism with an integrated spring system that automatically controls latch movement, eliminating the component failure mode where the faceplate moves to a position preventing disengagement.
Solution Approach 2:
The latch system transitions from a static faceplate-mounted arrangement to a dynamic spring-based system that automatically adjusts latch position. The spring mechanism provides continuous motion control, allowing the latch to smoothly transition between engaged and disengaged states without the positioning issues of fixed faceplate mounting.
3Device complexity
If a simple latch mechanism is used, then the device complexity is reduced, but the latch cannot maintain reliable latching position
Solution Approach 1:
The patent combines the latch body and spring mechanism into a single integrated assembly mounted to the follower door. This merging of components achieves reliable latching through the spring's continuous force application while maintaining relatively simple overall structure compared to separate actuation systems.
Solution Approach 2:
The spring mechanism provides self-regulating force to maintain the latch in the engaged position. The automatic spring pressure ensures reliable latching without requiring complex external actuation or adjustment mechanisms, achieving stability through the inherent elastic properties of the spring.
Data Source
AI summary
A latch assembly (10) is mounted to a follower door (275) of a double door (257) and includes a latch (231) and a pressing board (453) pivotably received in a cutout (411) of the latch (231). When the follower door (275) moves from an open position to a closed position, a pressing side (457) of the pressing board (453) is pressed by a top beam (35) of a door frame (31). The pressing board (453) pivots and presses against a bottom face (413) of the cutout (411) of the latch (231), moving the latch (231) from an unlatching position to the latching position until the pressing side (457) of the pressing board (453) completely enters the cutout (411), and then a slant face (236) of the latch (231) presses against the door frame (31), causing movement of the latch (231) from the latching position to the unlatching position.