Latch Device Clutch Mechanism Prevents Handle Damage
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Solution Overview
Problem
Components of outer operational devices in door locks are prone to deformation or damage when the handle is forcibly pivoted while the latch device is in a locked state, especially when the handle is in the form of a lever that amplifies the applied force.
Innovation Solution
A latch device with a clutch function is designed, featuring a case with pegs, a rocker, follower, connection member, push block, sliding block, clutch, and unlatching member, which allows the handle to pivot freely without moving the latch bolt when the lock is in the locked state, preventing damage to the operational device components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the handle is forcibly pivoted while the latch device is in the locked state, then the burglarproof or curfew purpose is achieved, but the components of the outer operational device are liable to deform or damage
Solution Approach 1:
The patent introduces a clutch mechanism as an intermediary between the handle and the latch bolt. When the lock is in the locked state, the clutch disengages the connection, allowing the handle to pivot freely without transmitting force to the latch bolt. This mediator protects the components from damage while maintaining the burglarproof function.
Solution Approach 2:
The clutch mechanism dynamically changes the connection state between the handle and latch bolt based on the lock state. In the locked state, the clutch allows relative movement (handle can pivot freely). In the unlocked state, the clutch establishes a rigid connection. This dynamic adaptation resolves the contradiction by changing the system's mechanical properties according to operational requirements.
2Ease of operation
If the handle is in the form of a lever that amplifies the force applied, then the ease of operation is improved, but the damage to components when forcibly pivoted is aggravated
Solution Approach 1:
The clutch acts as a protective intermediary that blocks the transmission of amplified forces from the lever handle to the latch bolt when in the locked state. This allows the lever design to maintain its mechanical advantage for normal operation while preventing the harmful effect of force amplification during forced pivoting.
3Strength
If the clutch mechanism is added to allow free pivoting in locked state, then the component damage is prevented, but the device complexity increases
Solution Approach 1:
The clutch mechanism is integrated with existing components of the latch device. The clutch assembly combines the push block, sliding block, and engagement features with the latch bolt and handle connection structures. This merging approach adds the necessary protection function while minimizing the increase in overall device complexity.
Solution Approach 2:
The clutch mechanism is divided into separable functional elements: a push block that moves linearly, a sliding block that engages/disengages, and connection features on existing components. This segmentation allows for modular manufacturing and assembly, reducing the complexity burden of adding the protective function.
Data Source
AI summary
A latch device (14) includes a latch bolt (30) movable between a latching position and an unlatching position. A sleeve (775) is mounted to an outer side (13A) of a door (11) and operatively connected to an outer operational device (12). A clutch (575) is mounted to and jointly movable with the sleeve (775). An unlatching member (711) is operably connected to the latch bolt (30) and releasably engaged with the clutch (575). When the unlatching member (711) engages with the clutch (575), operation of a handle (502) of the outer operational device (12) retracts the latch bolt (30). When the unlatching member (711) disengages from the clutch (575), the latch bolt (30) remains in the latching position if the handle (502) is rotated.