Vehicle Door Latch Second Outside Lever Impact Protection
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Solution Overview
Problem
Existing vehicle door latch devices are unreliable in maintaining the door closed after the outer panel is deformed by impact, due to issues with resilient members deteriorating over time and incorrect layout of components, leading to accidental door opening.
Innovation Solution
The design incorporates a second outside lever that is biased by a torsion spring and has an elongate hole to pivot within the vehicle, allowing it to move inward and prevent the first outside lever from turning, ensuring the ratchet remains engaged with the latch even if the outer panel is deformed, thus maintaining the door closed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer panel is deformed inward by impact, then the connecting portion or motion-transmitting member comes in contact with the deformed panel, but the door latch device becomes unreliable and the door may open accidentally
Solution Approach 1:
The outside lever is divided into two separate levers: a first outside lever connected to the outside handle, and a second outside lever biased by a torsion spring. This segmentation allows the second lever to independently respond to impact forces by moving inward through the elongate hole, preventing the first lever from turning and maintaining the door closed state even when the outer panel is deformed.
Solution Approach 2:
The second outside lever acts as an intermediary component between the deformed outer panel and the first outside lever. When impact deforms the outer panel, the second lever moves inward through the elongate hole and physically blocks the first lever from rotating, thereby mediating the impact force and preventing accidental door opening.
2Reliability
If a space is made between the outer panel and door latch device to prevent accidental opening, then the door remains closed during impact, but the room space of the vehicle becomes smaller
Solution Approach 1:
The second outside lever is designed to dynamically respond to impact forces by moving inward through the elongate hole when the outer panel deforms. This dynamic movement eliminates the need for a fixed safety space between the outer panel and latch device, as the lever automatically adjusts its position to prevent accidental opening only when needed, thereby preserving vehicle room space during normal operation.
3Reliability
If the lift lever is elastically supported by a shaft and compression spring, then the lever can move to contact the projection during impact, but the supporting force becomes weaker due to aging and sliding wear
Solution Approach 1:
The invention extracts the resilient support function from the traditional shaft-compression spring assembly and replaces it with a torsion spring directly mounted on the pivot shaft. This eliminates the sliding wear between the compression spring and shaft head, removing the source of progressive supporting force degradation while maintaining the ability to move the lever during impact.
Solution Approach 2:
Instead of using a resilient member that degrades over time, the invention uses a torsion spring that provides consistent elastic torque without sliding contact. The torsion spring copies the desired resilient support function but implements it through a different mechanical principle that avoids the wear and aging deterioration problems of compression springs.
4Reliability
If the drive rod striking member is added to prevent accidental opening, then the door remains closed during impact, but the layout in the door becomes more complex
Solution Approach 1:
The second outside lever serves multiple functions: it transmits opening force from the outside handle through the first lever, responds to impact forces by moving inward, and prevents the first lever from rotating during impact. This multi-functionality eliminates the need for separate components like the drive rod striking member, maintaining reliability while simplifying the overall system layout.
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
This configuration enhances the reliability of the door latch system by preventing accidental opening of the door even when the outer panel is deformed, as the second outside lever can move independently to maintain the ratchet-latch engagement, ensuring the door remains closed.
Implementation Method 1
a second outside lever (81) inward of the vehicle, pivotally mounted to the back member (19) about a pivot shaft (26) extending almost in parallel with the outer panel (2a) or longitudinally of the vehicle; a torsion spring (30) about the pivot shaft (26), the other end (302) of which is in contact with the second outside lever (81), thereby applying a torque onto the first and second outside levers (80, 81) and outward force onto the first outside lever (80)
Data Source
AI summary
In a vehicle door latch device, a first outside lever is pivotally mounted via a pivot shaft, and second outside lever is connected to an outside handle on an outer panel of a door via a motion-transmitting member to move toward the inside of a vehicle. Usually, turning of the second outside lever for disengaging a latch from a striker is transmitted to the first outside lever. If the second outside lever is impacted by an external force, the outer panel is deformed to move the second outside lever inward of the vehicle with respect to the first outside lever. But release turning of the second outside lever cannot be transmitted to the first outside lever. Even if the door is deformed by the external force, the door is still closed.