Bistable Retaining Member for Automotive Electric Lock Pawl Stability
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Solution Overview
Problem
Conventional electric locks for motor vehicle openings, such as doors and tailgates, often fail to reliably maintain both open and closed positions due to insufficient reaction forces, especially in cold temperatures or with snow accumulation, leading to unintended lock states during untimely pawl movements.
Innovation Solution
An electric lock design featuring a bistable retaining member with a cam and ramp mechanism, guided by a disengagement arm and driven by a control wheel, ensures the pawl remains in a stable position, preventing unwanted rotation and maintaining lock stability through bistable elastic return and a hooking tooth mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electric lock uses only a spring to return the pawl to the bolt, then the structure is simple, but the pawl cannot be reliably retained in the separated position when reaction force is insufficient (cold temperatures, snow accumulation, seal wear)
Solution Approach 1:
The retaining member is designed as a bistable mechanism that can dynamically switch between two stable positions: a first stable position where it retains the pawl in the separated position, and a second stable position where it allows the pawl to engage the bolt. This dynamic switching capability allows the system to adapt to different operational states while maintaining reliable pawl retention when needed.
Solution Approach 2:
The retaining member acts as an intermediary between the pawl and the bolt, controlling whether the pawl can engage the bolt or remain separated. By introducing this intermediate controlling element, the system achieves reliable pawl retention in the separated position without requiring direct complex mechanisms between the pawl and bolt.
2Reliability
If the pawl is freely returnable to the bolt by spring force, then the lock can close normally, but violent shocks can cause the pawl to fly away and catch on the locking means, blocking the lock from closing or causing undesired opening
Solution Approach 1:
The retaining member is positioned to preemptively prevent the pawl from moving into harmful positions during violent shocks. By maintaining the pawl in a controlled separated position or ensuring proper engagement, the system counteracts the harmful effect of shock-induced pawl movement before it can cause blocking or undesired opening.
Solution Approach 2:
The bistable retaining member provides a cushioning effect by absorbing shock energy through its stable position transitions. When violent shocks occur, the retaining member's bistable mechanism prevents the pawl from flying away uncontrollably, cushioning against the harmful effects before they can disrupt lock operation.
3Ease of operation
If the pawl is retained away from the bolt during opening, then the bolt can rotate freely, but without a positive retention mechanism the pawl may return to block the bolt rotation
Solution Approach 1:
The retaining member dynamically switches between retaining the pawl in the separated position during opening and allowing pawl-bolt engagement during closing. This dynamic control ensures the bolt can rotate freely when opening while maintaining reliable open position, and then properly engaging when closing is required.
Solution Approach 2:
The disengagement means provides feedback control by detecting when the bolt has completed its rotation and automatically returning the retaining member to allow pawl engagement. This feedback mechanism ensures the pawl is retained away from the bolt only during the necessary opening phase, then automatically re-engages to maintain the open position reliably.
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 solution ensures reliable operation of the electric lock in both open and closed positions, even under conditions of reduced reaction forces or violent shocks, by maintaining the pawl in a separated position and preventing untimely movements, thus enhancing user convenience and lock reliability.
Implementation Method 1
the disengaging means comprises a cam, carried by said bolt, capable of cooperating with the second active face of the retaining member
Implementation Method 2
said retaining member being subjected to a bistable elastic return
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to an electric lock for the opening of an automotive vehicle, that comprises: a pivoting bolt (3) interacting with a pin; a pawl (5) pivoting between an open position and a closed position of the lock, said pawl (5) being submitted to an elastic return force that urges it against said bolt (3) and being capable of interaction with said bolt (3) for preventing the rotation of said bolt (3) into the closed position of the lock; a driver (7) pivotally connected to the pawl (5); a retaining member (9) capable of retaining the driver-pawl assembly (7, 5) in a position away from said bolt (3) the retaining member (9) is submitted to an bistable elastic return force in order to be urged by it either into an active stable retaining position of the driver-pawl assembly (7, 5) for retaining the pawl (5) in a position away from the bolt (3), or into a rest stable position in which the retaining member (9) is maintained away from the driver-pawl assembly (7, 5), thus preventing any interaction between the retaining member (9) and the driver-pawl assembly (7, 5).