Coupling Mechanism Play for Anti-Tamper Door Locking
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Solution Overview
Problem
Conventional door and window locking mechanisms can be unintentionally or unauthorizedly unlocked by direct manipulation of the connecting rod, especially in tilted positions, where the drive rod is easily accessible and can be moved from a closed to an unlocked position without actuating the handle.
Innovation Solution
The coupling mechanism is designed with intentional play between its components in the closed position, allowing slight displacement of the connecting rod without canceling the closed state, and is blocked to prevent further movement, ensuring that the closed position remains secure even if the connecting rod is manipulated directly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coupling mechanism is designed without play between components, then the locking position is securely maintained, but the mechanism becomes vulnerable to unauthorized unlocking when the drive rod is directly manipulated
Solution Approach 1:
The coupling mechanism incorporates a controlled play or clearance between components that allows dynamic adjustment. When the drive rod is displaced without actuating the actuating device, the play absorbs the displacement while the blocking mechanism engages to prevent further movement. This dynamic design maintains security while accommodating direct manipulation attempts.
Solution Approach 2:
The coupling mechanism acts as an intermediary between the drive rod and the actuating device. It includes a blocking mechanism that mediates the interaction: allowing normal operation through the actuating device while preventing direct actuation of the drive rod from unlocking the system. The play between components serves as the mediating element that enables this selective control.
2Ease of operation
If the coupling mechanism allows displacement of the drive rod without actuating the actuating device, then normal operation is maintained, but unauthorized unlocking becomes possible
Solution Approach 1:
The coupling mechanism uses a blocking element that dynamically responds to displacement sources. When displacement comes from the actuating device, the mechanism allows movement through the play. When displacement comes directly from the drive rod, the blocking mechanism engages to prevent further movement, thus preventing unauthorized unlocking while maintaining normal operation.
Solution Approach 2:
The coupling mechanism is designed with asymmetric functionality: it allows displacement in one context (actuated through the actuating device) but blocks displacement in another context (direct manipulation of the drive rod). The blocking mechanism creates an asymmetric response based on the source of displacement, enabling differentiated control over the two scenarios.
3Reliability
If the play between components is increased to allow greater displacement, then the blocking mechanism engages more reliably, but the mechanism becomes less precise in maintaining the closed position
Solution Approach 1:
The play between components is designed to be sufficient to absorb small displacements and engage the blocking mechanism reliably, but not so large as to compromise the precision of the closed position. The play is carefully dimensioned to provide just enough clearance for the blocking action to engage while maintaining adequate positioning accuracy for the application.
Data Source
Figure 1~2
AI summary
The arrangement has a driving rod (18) operatively coupled with an actuator device i.e. handle, over a coupling mechanism (12) and displaceable between a locked position and an unlocked position and vice-versa by the actuator device. A clearance (X) is provided between teeth (16a-16e) and recesses (20a-20e) of the coupling mechanism in the locked position of the driving rod, where displacement of the driving rod is enabled without operation of the actuator device and without canceling the locked position such that the displaced driving rod is blocked with the coupling mechanism. The recesses are formed as holes or slots.