Adjustable Latch Mechanism for Secure Door Locking
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Solution Overview
Problem
Existing lock devices with adjustable latch systems fail to meet high safety standards, as they allow unauthorized access and manipulation, particularly when an intruder gains entry through a window, enabling easy exit without a key.
Innovation Solution
A lock device with a blocking member and an adjustable latch mechanism that prevents the second follower from releasing the lock bolt unless the latch device is in a latching state, ensuring the lock bolt remains locked, and includes a mechanical cooperation between the latch device and the lock bolt to maintain the latching state, even when the lock bolt is in its locked position, making it difficult to manipulate the lock by insertion of tools or external forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a thumb turn is provided for easy unlocking from inside, then ease of operation is improved, but security deteriorates as unauthorized persons can easily unlock the door
Solution Approach 1:
The lock device provides dynamic functionality by allowing the thumb turn to be either enabled or disabled through the adjustable latch device. The system transitions between two operational states: when the latch device is in the first position, the thumb turn functions normally for easy unlocking; when in the second position, the thumb turn is rendered inoperative, preventing unauthorized access while maintaining the same physical component
Solution Approach 2:
The adjustable latch device changes the operational parameter of the thumb turn from 'enabled' to 'disabled' state. By mechanically adjusting the latch device between two positions, the system alters the functional state of the thumb turn without changing its physical structure, thereby adapting security levels based on user needs
2Reliability
If a thumb turn latch is activated to prevent unauthorized exit, then security is improved, but ease of operation deteriorates as key operation becomes more complex
Solution Approach 1:
The lock device provides self-service functionality where the same key that locks the door also activates the thumb turn latch through the key-operated mechanism. The key operation simultaneously performs two functions: securing the bolt and enabling the thumb turn latch, eliminating the need for separate controls or complex procedures
3Adaptability or versatility
If the latch device is made adjustable between two positions, then adaptability is improved, but device complexity increases
Solution Approach 1:
The invention merges multiple functions into a single integrated mechanism. The adjustable latch device combines the thumb turn latch functionality with the existing lock mechanism, using shared components such as the key-operated cylinder and mechanical linkages. This integration allows the system to provide adjustable security features without proportionally increasing overall device complexity
Data Source
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AI summary
Lock device comprising a lock housing (1) which houses: a lock bolt (40) which is movable between an unlocked position and a locked position, a first follower (10), a second follower (20), and a blocking member (62) which is coupled to the first and to the second follower and which, by means of each of the first and second follower, can be manoeuvred between a blocking position, in which the lock bolt is blocked in its locked position, and a release position, in which the lock bolt is movable to the unlocked position. A latch device (80) is adjustable between a latching state, in which manoeuvring of the blocking member by means of the second follower from the blocking position to the release position is blocked, and a non-latching state, in which manoeuvring of the blocking member by means of the second follower from the blocking position to the release position is permitted. The latch device (80) is designed such that, when the lock bolt (40) is located in its locked position and the latch device has adopted its latching state, by mechanical cooperation with the lock bolt, the latch device is blocked against being adjusted from its latching state to its non-latching state.