Asymmetric Blocking Teeth for Motor Vehicle Seat Latching Fitting
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Solution Overview
Problem
Existing latching fittings for motor vehicle seats have equal cogging torque in both directions of rotation, which can lead to malfunction or slipping, and require complex control curves to prevent slipping and ensure reliable blocking.
Innovation Solution
A latching fitting with asymmetrical blocking teeth on the cover plate and base plate, allowing for a significantly higher cogging torque in one direction of rotation than the other, and featuring a blocking arm that can shift from a locked to unlocked position smoothly without stop-slip motion, even when loaded, with a spring mechanism to maintain the locked position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If symmetrical blocking teeth are used in latching fittings, then the structure is simple and manufacturing is easy, but the cogging torque is equal in both rotation directions which can lead to malfunction or slipping
Solution Approach 1:
The patent applies asymmetry by designing blocking teeth with different geometries for different rotation directions. The first blocking teeth on the cover plate and second blocking teeth on the base plate are configured with asymmetric profiles that create different cogging torques for clockwise and counter-clockwise rotation, thereby preventing malfunction and slipping while maintaining reliability
2Reliability
If complex control curves are used to prevent slipping, then reliability is improved, but the device complexity increases
Solution Approach 1:
Instead of using complex control curves, the patent employs asymmetric blocking tooth geometries that inherently provide different cogging torques for different rotation directions. This asymmetric design simplifies the overall structure by eliminating the need for complex control mechanisms while maintaining high reliability
3Reliability
If a latching fitting is designed to maintain locked position under load, then reliability is improved, but smooth unlocking becomes difficult
Solution Approach 1:
The patent applies inversion by designing the asymmetric blocking teeth such that the stronger cogging torque in one direction maintains the locked position under load, while the weaker cogging torque in the opposite direction facilitates smooth unlocking. This reversed approach allows the same structure to provide both strong locking and easy unlocking functionality
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 latching fitting provides enhanced reliability and safety by allowing smooth unlocking even under load, reducing wear and noise, and maintaining the locked position without user intervention, with a cogging torque of up to 2000 Nm, enabling precise backrest positioning.
Implementation Method 1
featuring a blocking arm that can shift from a locked to unlocked position smoothly without stop-slip motion, even when loaded, with a spring mechanism to maintain the locked position
Data Source
AI summary
The invention relates to a latching fitting (10), in particular for a seat of a motor vehicle. The latching fitting (10) comprises a base plate (20), a cover plate (30), at least one blocking arm (40, 140) and an actuating plate (50). The cover plate (30) is rotatable relative to the base plate (20) and has an internal toothing (31). The blocking arm (40, 140) is arranged on the base plate (20) and is pivotable between an unlocked position, in which rotation of the cover plate (30) relative to the base plate (20) is possible, and a locked position, in which rotation of the cover plate (30) relative to the base plate (20) is blocked. The actuating plate (50) is rotatable relative to the base plate (20) and shifts the blocking arm (40, 140) between the unlocked position and the locked position. The internal toothing (31) has first blocking teeth (34) which have a vertex (35) and which are formed asymmetrically with respect to a radial axis (A) which runs through the vertex (35). The blocking arm (40, 140) has second blocking teeth (44) which are adapted for meshing with the first blocking teeth (34).