Mortise Lock Delayed Rod Extension Mechanism
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Solution Overview
Problem
Existing mortise locks and counter boxes require a downward impulse from the upper rod to unlock, which can lead to premature extension of the lower rod, causing damage due to grinding marks on the floor.
Innovation Solution
The solution decouples the extension movements of the upper and lower rod connections, ensuring the lower rod only extends when the door is fully closed, by using a switch lock that activates only when the upper rod is in the correct position, and employs a locking mechanism with a pull rod and unlocking lever to delay the extension of the lower rod connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a downward impulse from the upper rod is required to unlock the upper rod connection, then the locking mechanism can be actuated, but the lower rod may extend prematurely causing damage to the floor
Solution Approach 1:
The locking mechanism is divided into two independent rod connections (upper and lower) with separate control paths. The upper rod connection is controlled by the switching nut and switching lock, while the lower rod connection is controlled by a separate locking slide and spring mechanism. This segmentation ensures that the upper rod can be unlocked without necessarily triggering the lower rod extension, preventing floor damage.
Solution Approach 2:
The switching lock is designed to engage with the striking plate at a predetermined position before the lower rod would extend. This preliminary engagement creates a mechanical interlock that prevents the lower rod from extending prematurely. The switching lock must be activated first, which then enables or controls the subsequent extension of the lower rod through the locking slide mechanism.
2Device complexity
If the upper rod connection and lower rod connection are coupled together, then the locking mechanism is simplified, but the lower rod extends simultaneously with the upper rod causing potential damage
Solution Approach 1:
The coupling between upper and lower rod connections is segmented into controlled stages. While the switching nut controls both rod connections, the switching lock and locking slide mechanisms create independent control stages that allow the upper rod to extend first, with the lower rod following only after the switching lock engages with the striking plate.
Solution Approach 2:
The switching lock performs a preliminary action by engaging with the striking plate before the lower rod connection is permitted to extend. This preliminary engagement acts as a gatekeeper that must be satisfied before the lower rod can extend, preventing simultaneous extension that would cause floor damage.
3Ease of operation
If the switching lock is positioned outside the door, then activation is simplified, but the bolt projection must be precisely controlled to ensure proper engagement
Solution Approach 1:
The bolt is designed with a bolt projection that extends beyond the switching lock in the activated state, creating a mechanical cushion or stop. This extra projection ensures that even with variations in manufacturing precision, the bolt will engage with the striking plate at the correct position. The switching lock's external positioning allows this cushioning effect to occur, compensating for dimensional tolerances.
Data Source
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AI summary
The invention relates to a strike plate (1) or a mortise lock, with an upper rod connection (10) for connecting an upper rod (12), a lower rod connection (11) for connecting a lower rod (13), and a lock mechanism comprising a switching nut (17) for actuating the rod connections (10, 11), wherein the lock mechanism is designed such that, for locking the rods (12, 13), initially only the upper rod connection (10) extends, while the lower rod connection (11) is locked in the retracted position by means of a locking device (31), and wherein only after reaching a predetermined extension position of the upper rod connection (10) is the locking device (31) unlocked and the lower rod connection (11) is released from the retracted position and extends, resulting in a delayed extension movement of the lower rod connection (11) relative to the upper rod connection (10).According to the invention, a switching lock (14) with bolt (15) is associated with the upper rod connection (11), which is provided for switching from an activated state, in particular with a smaller bolt projection, to a locked state, in particular with maximum bolt projection, and that the locking mechanism is designed such that the release of the lower rod connection (11) is only initiated when the switching lock (14) switches from the activated state to the locked state.