Self-locking Step-by-Step Mechanism for Vehicle Seat Adjustment
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Solution Overview
Problem
The existing self-locking stepping mechanisms for vehicle seat adjustments often experience unwanted idle strokes due to improper disengagement from the release wheel teeth, leading to imprecise input and modulation movements.
Innovation Solution
A self-locking stepping mechanism where the rocker arm is fixed by a spring in its normal position until sufficient torque is applied, allowing it to pivot and engage with the release wheel teeth, with features like projections and indentations for secure holding, a tongue to prevent overdriving, and a braking tab to control rotation, ensuring precise control and preventing free rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rocker arm moves synchronously with the actuating lever, then the mechanism is simpler, but unwanted idle strokes occur and precision is reduced
Solution Approach 1:
The rocker arm's state is dynamically changed from always moving (synchronous) to selectively moving (self-locking). The mechanism transitions between locked and unlocked states based on torque threshold, allowing precise control while maintaining simplicity. The spring-loaded latching mechanism enables the rocker arm to remain stationary during normal operation and only move when sufficient torque is applied.
2Speed
If the driver engages with release wheel teeth immediately, then the mechanism responds faster, but improper disengagement causes idle strokes
Solution Approach 1:
The driver is preliminarily positioned by the actuating lever before engaging with the release wheel teeth. The rocker arm acts as a gatekeeper that must be unlocked first, ensuring proper sequencing. This preliminary positioning prevents premature or improper engagement, eliminating idle strokes while maintaining controlled response speed.
3Reliability
If the spring holding force on the rocker arm is strong, then the self-locking is more reliable, but more torque is required to initiate movement
Solution Approach 1:
The spring force parameter is optimized to provide sufficient holding force for reliable self-locking during normal operation, while the torque threshold remains achievable for intended actuation. The spring constant and pre-load are specifically selected to create a balance between holding reliability and actuation feasibility.
4Adaptability or versatility
If the rocker arm is always free to rotate, then the mechanism is more flexible, but free rotation causes unwanted idle strokes
Solution Approach 1:
The spring-loaded latching mechanism applies a preliminary restraining force on the rocker arm to prevent unwanted rotation. This anti-action (locking) is in place before any actuation occurs, ensuring the rocker arm remains stationary unless deliberately unlocked by sufficient torque applied through the driver and actuating lever.
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 solution enhances precision and prevents unwanted idle strokes by ensuring the rocker arm engages and disengages correctly with the release wheel teeth, providing a reliable and controlled movement mechanism for vehicle seat adjustments.
Implementation Method 1
The rocker arm is fixed in its normal position by the spring
Implementation Method 2
the spring exerts on the rocker arm can be overcome
Implementation Method 3
a braking tab be provided, which rests against the rocker arm in a rubbing manner. This tab creates a friction torque. It brakes the rotary movement of the rocker arm
Data Source
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AI summary
The self-locking step-by-step mechanism for an adjustment device of a vehicle seat has a clamping roller lock and a step-by-step device. The clamping roller lock has an axis (20) and a release wheel (22) which is rotatable about said axis (20) and has a toothing. The step-by-step device has a) an actuating lever (24) which is mounted pivotably about the axis (20), b) a driver (26) which is mounted on the actuating lever (24) so as to be pivotable about a driver axis (32) and which has two driver regions (28) which interact with the toothing of the release wheel (22) and of which only one is in engagement in each case with the toothing in one direction of rotation of the release wheel (22), of which both are disengaged from the toothing in a central position of the actuating lever (24), and of which one comes into engagement with the toothing and rotates the release wheel (22) when the actuating lever (24) is pivoted out of the central position thereof whereas the other remains disengaged from the toothing, c) a drag lever (34) which has supporting surfaces (62) which enter into contact with the driver (26), and d) a spring (38). The spring (38) has at least one projection (40). The drag lever (34) has at least one indentation (42) which is normally in engagement with the projection (40). The spring (38) is fixed against rotating.