Locking Device Latch Bolt Blocking Element Mechanism
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Solution Overview
Problem
Conventional mortise locks are vulnerable to premature extension of the latch bolt when manually actuated, leading to potential damage and unsuitability for fire protection doors, due to the accessible trigger mechanism allowing unintended operation.
Innovation Solution
A locking device with a transversely projecting pin on the latch bolt and a displaceable blocking element, coupled with an additional latch and drive mechanism, prevents the latch bolt from extending unless the door is properly closed, ensuring the blocking element engages to block the latch bolt's displacement path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the trigger is made accessible on the latch bolt for easy actuation, then the ease of operation is improved, but the reliability deteriorates due to unintended activation and manual manipulation
Solution Approach 1:
The trigger mechanism is extracted from the latch bolt and relocated to the lock case. The trigger shaft and trigger arm are now housed within the lock case, separated from the latch bolt's external surface. This extraction eliminates the vulnerability of having an accessible trigger on the latch bolt while maintaining the functional connection through the trigger arm that actuates the blocking element to release the latch bolt when needed.
2Ease of operation
If the latch bolt is allowed to extend freely without blocking, then the ease of operation is improved, but the object-affected harmful factors increase due to potential damage from premature extension
Solution Approach 1:
The blocking element is positioned in advance within the lock case to preemptively prevent the latch bolt from extending beyond its intended position. Before the latch bolt can potentially cause damage by premature extension, the blocking element is already in place to stop it. The blocking element is displaceable so it can be moved out of the way when proper closing action occurs, allowing controlled extension only when appropriate.
3Reliability
If a blocking element is added to prevent manipulation, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The blocking element is merged with the existing trigger mechanism within the lock case. The same trigger arm that controls the latch bolt also controls the blocking element's position. This merging means that the blocking function is achieved using components already present in the lock mechanism, rather than adding a completely separate blocking system. The trigger arm serves dual purposes: controlling both the latch bolt and the blocking element.
Solution Approach 2:
The trigger arm serves multiple functions: it controls the latch bolt's extension, controls the blocking element's position, and responds to both manual actuation and automatic door closing forces. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in device complexity while achieving reliable manipulation prevention.
Data Source
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AI summary
The locking device (10) has a latch bolt (14) provided with a latch shaft (20) and a locking element that transfers the bolt from a closing position into a locking position. A blocking element (22) is provided in a lock case (12) for blocking displacement of the bolt. The bolt includes a clamping element to which the blocking element is engaged. The blocking element is led from a path of the clamping element using an auxiliary latch (16). The clamping element is formed from a pin protruded transverse to respective displacing directions of the bolt and the blocking element.