Motor Vehicle Door Lock Inertial Blocking
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Solution Overview
Problem
Existing motor vehicle door locks fail to effectively prevent opening due to inertial forces during a side impact, requiring complex adjustments and geometric dependencies, and often result in permanent blocking or stress on the kinematic chain.
Innovation Solution
A lock design featuring a movable control means with a cam and blocking mechanism, utilizing an elastic return means and cam profile with a slope break to trigger blocking only when acceleration exceeds a threshold, allowing for independent and adjustable blocking without geometric constraints.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blocking system using deformation of the door sheet metal is used, then the lock can be blocked during impact, but the system requires adaptation to door geometry and causes permanent deformation
Solution Approach 1:
The invention extracts the blocking function from the door structure itself and relocates it to the lock assembly. The cam and blocking means are self-contained within the lock, eliminating the need to deform or adapt the door sheet metal. This allows the blocking mechanism to be independent of door geometry while maintaining reliable blocking during impact.
Solution Approach 2:
The cam profile acts as an intermediary element that translates the inertial movement of the opening lever into blocking action. Instead of directly deforming the door or using complex geometric adaptations, the cam profile mediates between the lever movement and the blocking function, providing a simple geometric solution that is independent of door geometry.
2Reliability
If an inertial blocking wedge mounted on the opening lever is used, then the lock can be blocked during impact, but the system requires good knowledge of impact characteristics and precise synchronization of adjustment movements
Solution Approach 1:
The blocking mechanism is self-activating based on the inertial movement of the opening lever itself. The cam profile is fixed to the lever, so the lever's own movement during impact automatically triggers the blocking action. No external adjustment or synchronization is needed - the system uses the lever's inherent motion characteristics to activate blocking when required.
Solution Approach 2:
The invention changes the parameter from requiring precise adjustment of wedge position and synchronization to using a fixed cam profile geometry. The blocking threshold is determined by the cam profile shape and spring characteristics rather than adjustable parameters, eliminating the need for complex adjustment procedures while maintaining reliable blocking.
3Reliability
If blocking is achieved by deforming the door sheet metal, then the lock can be blocked during impact, but the door cannot be opened after the impact
Solution Approach 1:
The blocking mechanism is dynamic rather than static. The cam profile allows the blocking means to move between engaged and disengaged positions based on the inertial forces acting on the lever. After impact, when normal forces return, the spring automatically returns the blocking means to its initial position, restoring opening functionality without requiring door deformation or manual intervention.
Solution Approach 2:
The blocking action is temporary and automatically discarded after serving its protective function. The elastic return means (spring) recovers the blocking means to its initial position after impact, allowing the door to be opened again. This eliminates the permanent blocking effect of door deformation while maintaining protection during impact.
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 lock effectively blocks door opening during inertial forces while allowing easy reopening without complex adjustments or stress on the kinematic chain, ensuring robustness and ease of use post-impact.
Implementation Method 1
an elastic return means configured to bring said blocking means to rest on the cam profile
Implementation Method 2
the cam profile comprising a slope break configured to bring the blocking means from the rest position to the active blocking position when the cam pivots around its axis towards the opening direction of the sash with greater acceleration at a predetermined threshold value
Data Source
AI summary
A lock (1) for a motor vehicle door (2) comprising: a movable control means (13), an opening lever (15) for opening said door (2) intended to allow the door (2) to open, comprising a cam (17) movable in rotation about an axis of rotation (18) and attached to said control means (13) at an attachment area (19) so as to be driven in rotation when the control means (13) is moved, a blocking means (21) configured to assume an active blocking position in which said blocking means (21) blocks said cam (17) and an idle position in which said blocking means (21) is in contact with the cam (17) on a cam profile (25) and allows said cam (17) to move, an elastic return means (23) configured to bring said blocking means (21) to bear on the cam profile (25), the cam profile (25) comprising a knee (15a) configured to bring the blocking means (21) from the idle position to the active blocking position when the cam (17) pivots about the axis of same (18) towards the direction of opening of the door (2) with an acceleration greater than a predefined threshold value.