Self-locking Ratchet Latch Assembly for Vehicular Door Anti-chucking
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Solution Overview
Problem
Vehicular door latching systems in pillar-less configurations experience undesirable 'chucking' noise due to relative movement between the ratchet and striker, which existing anti-chucking solutions fail to fully eliminate, requiring high release and latching efforts.
Innovation Solution
A latch assembly with a self-locking ratchet mechanism incorporating a pawl and anti-rattle lever, featuring a lock tooth and notch configuration that inhibits movement between the ratchet and striker, preventing over-travel and chucking noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional ratchet mechanism is used to latch the striker, then the door can be closed and latched, but relative movement between the ratchet and striker occurs causing chucking noise
Solution Approach 1:
The latch mechanism transitions from a static ratchet position to a dynamic self-locking position. When the door is closed, the ratchet moves along the cam surface, and at the self-locking position, the pawl automatically engages with the ratchet tooth, creating a dynamic locking action that prevents further movement and eliminates chucking noise while maintaining reliable latching
Solution Approach 2:
The latch mechanism performs self-locking automatically without requiring additional actuation. The cam surface geometry causes the pawl to engage with the ratchet tooth at the self-locking position, and the spring force maintains this engagement, allowing the system to lock itself and prevent relative movement that would cause noise
2Object-affected harmful factors
If existing anti-chucking solutions are implemented, then some noise reduction is achieved, but high release and latching efforts are required
Solution Approach 1:
The cam surface geometry is designed to change the mechanical parameters of the latch mechanism. At the self-locking position, the cam angle and lever arm create optimal mechanical advantage, allowing the pawl to engage the ratchet tooth with minimal force. This geometric parameter optimization reduces both latching and release efforts while effectively preventing door rattle
Data Source
AI summary
A latch assembly for a vehicular latching system configured to provide an anti-chucking locking function in cooperation with a latch mechanism. The latch mechanism has a ratchet that is moveable by a striker between a striker release position, a striker capture position, and a striker over-travel position. A pawl is operable in a ratchet holding position to hold the ratchet when the ratchet is in the striker capture position and operable in a ratchet releasing position to release the ratchet to allow the ratchet to return to its striker release position. A latch release mechanism operates to move the pawl between its ratchet holding and ratchet releasing positions. The anti-chuck locking function is provided by the pawl having a lock tooth and the ratchet having a lock notch for locking engagement therebetween when the pawl holds the ratchet in its striker capture position for muting vibrations of the latch assembly.