Vehicle Seat Backrest Adjuster with Eccentric Cam Locking
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Solution Overview
Problem
Existing backrest adjusters for vehicle seats lack sufficient mechanical strength and ease of use, particularly under high torque conditions, and do not effectively allow for versatile positioning and easy entry into vehicle rear areas.
Innovation Solution
A backrest adjuster system featuring a dual-fitting mechanism with a transmission rod, a star-shaped or toothed ring profile, and a radially protruding adapter with stop elements, providing enhanced torsional strength and a detachable connection for easy assembly and disassembly, along with a spring mechanism for returning to initial positions, allowing for comfortable seating and easy entry configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional fitting mechanism is used for backrest adjustment, then the device complexity is low, but the mechanical strength and reliability under high torque conditions are insufficient
Solution Approach 1:
The fitting mechanism is divided into separate components: a first fitting part with a toothed ring, a second fitting part with guide segments and radially displaceable bolts, and an eccentric mechanism. This segmentation allows each component to be optimized for its specific function while maintaining overall mechanical strength without excessive complexity.
Solution Approach 2:
The bolt is nested within the guide segment, allowing radial displacement between locked and unlocked states. The eccentric mechanism is rotatably mounted within the fitting structure, enabling compact arrangement while providing the necessary mechanical advantage for high torque conditions.
2Reliability
If a manual release lever system is used, then the ease of operation is good, but the reliability under high torque conditions deteriorates
Solution Approach 1:
The guide segment acts as an intermediary between the bolt and the toothed ring, controlling the bolt's radial movement. The eccentric mechanism serves as a mediator that converts rotational motion into the radial displacement needed to engage or disengage the locking bolts, ensuring reliable operation under torque while maintaining ease of use.
Solution Approach 2:
The system changes the radial position parameter of the bolt between two states: engaged with the toothed ring for locking, and retracted for unlocking. The spring element changes the force parameter to maintain constant preload on the cam, ensuring reliable locking while allowing easy release when the lever is actuated.
3Reliability
If a locking mechanism with multiple components is implemented, then the reliability improves, but the ease of manufacture deteriorates
Solution Approach 1:
The fitting mechanism uses standardized components that can serve multiple functions: the toothed ring provides both the locking surface and the transmission path, the bolt serves both as a locking element and a position indicator, and the eccentric mechanism provides both the unlocking action and the force amplification. This multi-functionality reduces the total number of separate parts needed.
Solution Approach 2:
The spring element automatically maintains constant preload on the cam without external adjustment, and the eccentric mechanism self-locks in its rotational position. The guide segments automatically guide the bolt between its locked and unlocked positions, eliminating the need for complex adjustment mechanisms or precise manual assembly.
4Adaptability or versatility
If a complex transmission mechanism is used, then the adaptability for various positions improves, but the device complexity increases
Solution Approach 1:
The fitting mechanism transitions from a static locked state to a dynamic unlocked state through the rotation of the eccentric. The backrest can be held at multiple positions during adjustment, with the locking bolts engaging at different points on the toothed ring. This dynamic behavior provides adaptability for various positions without requiring a complex multi-position mechanism.
Solution Approach 2:
The patent replaces a complex multi-component transmission system with a simpler eccentric-cam mechanism. The eccentric's rotation directly controls the radial position of the locking bolts, eliminating the need for intermediate linkages, gears, or hydraulic systems. This substitution maintains adaptability while significantly reducing device complexity.
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 system provides improved mechanical stability under high torque conditions, enabling smooth and secure adjustment of the backrest for various comfort positions and easy entry into vehicle rear areas, while ensuring reliable operation and durability.
Implementation Method 1
a spring which is arranged between the lower arm and the cam for applying a preload force to the cam
Implementation Method 2
a spring which is arranged between the lower arm and the cam for applying a preload force to the cam
Implementation Method 3
at least one return spring, which is arranged, in particular, on the inside of the upper fitting
Implementation Method 4
at least one return spring, which is arranged, in particular, on the inside of the upper fitting
Data Source
Figure 1
Figure 2
Figure 3~4A
AI summary
A seat back adjuster (1) for a vehicle seat, said seat back adjuster having at least a fitting upper part (B1), a fitting lower part (B2) and a fitting (2) arranged therebetween, wherein a separate adapter (5) is arranged on a side of the fitting upper part (B1) or of the fitting lower part (B2) facing away from the fitting (2), said adapter being fixed on the fitting (2) through an opening in the fitting upper part (B1) or in the fitting lower part (B2), and wherein a control lever (4) is provided which is arranged on the side of the adapter (5) facing away from the fitting (2) and is interlockingly and/or frictionally connected to the adapter.