Convertible Top Latch Cams for Over-Center Opening Protection
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Solution Overview
Problem
Existing locking devices for convertible tops require significant force to lock and unlock, and lack adequate safeguards against unintentional opening.
Innovation Solution
A locking device with a pivotably mounted locking hook, actuating handle, and a pawl mechanism, featuring cams on the locking hook to prevent unintentional opening, ensuring the locking hook remains in an over-center position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking device is designed to create tight tension on the convertible top, then the locking reliability is improved, but the force required to lock and unlock increases
Solution Approach 1:
The locking mechanism utilizes dynamic over-center movement where the locking hook pivots past the vertical centerline into a self-locking position. This dynamic transition allows the system to build up tension force progressively, achieving high locking reliability while requiring manageable actuation force only during the transition phase.
Solution Approach 2:
The cam surface incorporated in the locking hook provides a curved geometric path that guides the bolt during engagement. This curvature enables smooth force distribution and progressive engagement, reducing the peak force required while maintaining reliable locking through the over-center position.
2Ease of operation
If a simple locking mechanism is used, then the ease of operation is improved, but the protection against unintentional opening is reduced
Solution Approach 1:
The over-center locking position creates a preliminary mechanical barrier that prevents unintentional opening. The locking hook must first be pulled back past the over-center point before any opening movement can occur, providing inherent protection against accidental activation while maintaining simple manual operation.
Solution Approach 2:
The locking mechanism is segmented into distinct functional elements: the locking hook for primary engagement, the cam surface for controlled movement, and the bolt for positioning. This segmentation allows each element to perform its specific function efficiently, maintaining ease of operation while achieving reliable protection through the combined over-center positioning system.
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
Provides a double safeguard against unintentional opening by maintaining the locking hook in an over-center position, reducing the required force for operation and enhancing security.
Implementation Method 1
at least one cam formed on the locking hook which, during an opening movement of the locking hook, strikes against the bolt and prevents further opening movement
Implementation Method 2
A spring acts on the bolt in such a way that the locking hook is in an over-center position
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
Locking device (1) for a movable roof element of a vehicle, comprising a pivotably mounted locking hook (4) which, in the locked position, locks the movable roof element to a receptacle (12) of a roof frame of the vehicle in the closed position, an actuating handle (3) which, for actuating the locking hook (4), is coupled to the locking hook (4) via a steering lever kinematic with a steering lever (9) and pivotably connected to the movable roof element via a bolt (6), and a pawl (8) for securing the locking device against unintentional opening in a first opening position in which the locking hook (4) is still engaged with the roof frame, wherein the pawl (8) is pivotably mounted on the actuating handle (3) via a pivot axis with pivot point (9a), and an over-center kinematic for securing the locking device against unintentional opening.wherein this includes at least one cam (15) formed on the locking hook (4) which strikes against the bolt (6) when the locking hook (4) opens and prevents further opening.