Motor Vehicle Door Latch With Segmented Pawls
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor vehicle latches with locking mechanisms comprising a catch and pawls are complex and heavy, making it difficult to achieve both stability and weight reduction while maintaining safety, especially under overload conditions.
Innovation Solution
A latch design with a primary pawl for ratcheting in the main ratchet position and a separate secondary pawl for ratcheting in the pre-ratchet position, where the secondary pawl only engages during overload, reducing complexity and weight by allowing load distribution between the primary and secondary pawls, and maintaining stability through elastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a complex motorized closure aid is used to execute the necessary pulling distance into the closed position, then the door can be brought into the scheduled closed position, but the construction weight increases
Solution Approach 1:
The locking mechanism is segmented into multiple pawls (primary pawl and secondary pawl) that perform different functions at different stages. The primary pawl handles normal operation while the secondary pawl provides overload protection, allowing the system to achieve motorized closure with reduced overall complexity and weight.
Solution Approach 2:
The system dynamically engages different pawls based on the operational conditions. Under normal loads, only the primary pawl is active, while under overload conditions, the secondary pawl engages to provide additional locking. This dynamic behavior allows for a lighter overall construction compared to a always-active complex mechanism.
2Stability of the object's composition
If the secondary pawl is always engaged with the catch, then stability is maximized, but the complexity and weight of the latch increase
Solution Approach 1:
The secondary pawl is positioned to engage with the catch only under specific overload conditions, not during normal operation. This localized engagement provides stability precisely when needed (during overload) while maintaining simplicity during normal operation, resolving the contradiction between constant stability and device complexity.
Solution Approach 2:
The system changes the engagement parameter of the secondary pawl based on the load condition. Under normal loads, the gap between the secondary pawl and catch is maintained, but under overload, the gap closes and engagement occurs. This parameter change allows the system to achieve high stability when needed without the constant complexity of a always-engaged mechanism.
3Reliability
If the gap between secondary pawl and catch is always closed, then overload protection is maximized, but the secondary pawl interferes with normal operation
Solution Approach 1:
The gap between the secondary pawl and catch dynamically opens and closes based on the applied load. During normal operation, the gap remains open to avoid interference, while during overload, the gap closes to engage the secondary pawl for protection. This dynamic behavior resolves the contradiction between constant overload protection and ease of normal operation.
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 design reduces the complexity and weight of the latch while ensuring increased stability and safety by distributing load effectively during overloads, allowing for a simpler and lighter automatic closure mechanism without compromising safety.
Implementation Method 1
in the case of overload a deformation of the catch and/or the primary pawl leads to closure of the gap
Data Source
Figure 1~2
AI summary
The invention relates to a latch for a door or flap of a motor vehicle with a locking mechanism comprising a catch (3), a primary pawl (1 ) for ratcheting with the catch (3) in a main ratchet position and a separate secondary pawl (2) for ratcheting with the catch (3) in a pre-ratchet position, whereby only in the case of overload can the secondary pawl (2) additionally ratchet to the primary pawl (1 ) with the catch (3) in the main ratchet position. The invention furthermore relates to a latch for a door or a flap of a motor vehicle with a locking mechanism comprising a catch (3) with a load arm (7) and a catching arm (8) a primary pawl (1 ) to ratchet with the load arm (7) of the catch (3) in a main ratchet position and a separate secondary pawl (2) to ratchet with the catching arm (8) of the catch (3) in a pre-ratchet position, whereby the catch (3), the primary pawl (1) and the secondary pawl (2) are arranged on the same plane A reduction of the complexity, e.g. an automatic closure aid and increased stability, i.e. the tensile strength are enabled simultaneously.