Push-Push Latch with Counterweight Hammer for Crash Reliability
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Solution Overview
Problem
Existing push/push latches in automotive applications are prone to unlatching during vehicle crashes, posing a safety risk due to their inability to withstand significant forces, and existing solutions either fail to prevent unlatching or are compromised by extreme forces, such as a blocking plate that may sever the pin or be ineffective in low-impact crashes.
Innovation Solution
A push/push latch design incorporating a hammer with a counter-weight that pivots to prevent the latch from opening during high and low g-force situations, such as vehicle crashes, by obstructing the path of the latch body, and returns to its neutral position once the force dissipates, allowing normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blocking plate is used to prevent the pin from moving in the track during unwanted forces, then the latch reliability under high force is improved, but the device complexity and weight increase
Solution Approach 1:
The patent employs a counterweight mechanism where a mass is positioned to create a moment that resists unwanted latch movement during high-force events like crashes. The counterweight works in conjunction with a lever arm to generate sufficient blocking force without requiring a heavy blocking plate, thus improving reliability while controlling device complexity
Solution Approach 2:
The blocking mechanism transitions from a static blocking plate to a dynamic system where the counterweight and lever arm can pivot and engage only when needed. This dynamic engagement allows the latch to remain simple during normal operation while providing enhanced reliability during high-force events, reducing overall device complexity
2Reliability
If a blocking plate is used to prevent pin movement, then high-force latch reliability is improved, but the pin may be severed under extreme forces
Solution Approach 1:
The patent introduces a lever arm as an intermediary between the counterweight and the pin. This lever arm distributes the blocking force across a larger area and provides mechanical advantage, reducing the concentrated stress on the pin that would otherwise cause it to sever under extreme forces while maintaining latch reliability
3Reliability
If a blocking plate is used to prevent unwanted latch movement, then latch reliability is improved, but the plate may not move sufficiently during low-impact crashes
Solution Approach 1:
The blocking mechanism is designed to be dynamic rather than static, allowing it to engage and disengage based on the magnitude of applied forces. The counterweight and lever arm system can pivot to engage the blocking position during both low and high-impact events, ensuring the latch responds appropriately to varying force levels without requiring a heavy plate that wouldn't move during low-impact crashes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The latch effectively remains in its open or closed position during crashes, preventing contents from becoming projectiles and ensuring occupant safety, while maintaining functionality after the force has subsided.
Implementation Method 1
a hammer with a counter-weight that pivots to prevent the latch from opening during high and low g-force situations
Data Source
AI summary
A push/push latch designed to operate in high and low g-force situations, which may be mounted horizontally or vertically. The latch includes a latch body, a track, a housing surrounding the track and latch body, a follower with a pin that moves in the track to actuate the push/push latch. The invention also includes a hammer that repositions when a g-force is applied to the latch to stop the movement of the track body thus preventing the latch from opening during a g-force situation such as a vehicle crash. The hammer may be connected to the housing or to the latch body.