Two-Pull Door Latch Reset Mechanism for Power-Loss Release
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Solution Overview
Problem
Existing door latch systems in vehicles may fail to function correctly in power and no-power scenarios, leading to inconsistent operation and potential premature release of doors due to timing issues and partial pulls, especially when a two-pull release system is required by regulations.
Innovation Solution
A two-pull, automatic reset latch system incorporating a release lever, coupling lever, reset lever, override link, and biasing member, with mechanisms to ensure decoupling during the first pull and automatic resetting before the second pull, using an electronic controller and motor to manage the latch system's state during power scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical two-pull release system is used, then the latch can be released manually in no-power scenarios, but the system timing and reset operation become problematic in power scenarios
Solution Approach 1:
A controller is introduced as an intermediary between the manual release handle and the latch mechanism. The controller receives signals from switches associated with the release handle and autonomously controls the motor to reset the latch, eliminating timing problems and ensuring reliable operation in both power and no-power scenarios.
Solution Approach 2:
The patent replaces the purely mechanical two-pull release system with an electromechanical system. A motor-driven mechanism substitutes for the traditional mechanical cable and lever system, allowing precise control of the latch state through electrical signals while maintaining manual override capability.
2Productivity
If the system decouples and becomes coupled again during the first pull, then the mechanical reset timing becomes critical, but this causes timing issues and potential premature release
Solution Approach 1:
The system incorporates feedback through switches that detect the position of the release handle and the state of the latch. This feedback enables the controller to monitor the system state continuously and activate the motor at the precise moment needed for resetting, eliminating guesswork and timing-critical mechanical designs.
Solution Approach 2:
The controller is programmed to initiate the motor reset action in advance based on detected handle position. When the release handle is actuated, the controller anticipates the need for reset and activates the motor proactively, ensuring the latch is ready for the second pull without requiring critical timing during the actual release sequence.
3Adaptability or versatility
If partial pulls are allowed, then the release system may partially unlock the door, but this does not reset the system and creates inconsistent operation
Solution Approach 1:
The system prevents partial unlocking by design. The motor-controlled mechanism ensures that the latch only transitions to the unlocked state when the controller explicitly commands it based on complete detection of the second pull sequence. Intermediate positions during partial pulls do not trigger release, and the system maintains its locked state until a proper reset sequence is completed.
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
Ensures reliable two-pull operation in both power and no-power conditions, preventing partial unlocking and ensuring the latch resets correctly before the second pull, meeting regulatory requirements for door release systems.
Implementation Method 1
The biasing member is adapted to exert a biasing force upon the coupling lever in the first rotational direction with respect to the second axis
Implementation Method 2
an electric motor adapted to drive the gear to rotate about the fourth axis and in a rotational driven direction
Data Source
AI summary
A two-pull, automatic reset, latch system is configured to operate during a no-power scenario and a power scenario. The latch system includes a release system, a release lever, and a coupling lever. The release lever is pivotally engaged to a stationary structure about a first axis. The coupling lever pivots about a second axis offset from the first axis, and is adapted to couple the release lever to the release system during a no-power scenario and upon two actuations of the release lever. The coupling lever is further adapted to maintain decoupling of the release lever from the release system during a power scenario.