Bidirectional Ratchet Mechanism for Compact Seat Height Adjustment
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Solution Overview
Problem
Existing pawl braking mechanisms in vehicle seats are complex, occupy large space, and primarily operate in a one-way rotating manner, making it cumbersome to adjust seat height accurately and requiring re-adjustment if the optimal height is missed.
Innovation Solution
A bidirectional driving device comprising a ratchet wheel, movable handle, fixed casing, and central shaft, with pawls and reset springs that allow for secure engagement and disengagement with ratchet teeth, enabling clockwise and counterclockwise rotation, and automatic resetting, utilizing sliding slots with different radii for directional control and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a pawl braking mechanism is used for one-way rotation control, then the seat height can be adjusted, but the structure becomes complicated and occupies large space
Solution Approach 1:
The patent combines two pawl mechanisms (first pawl and second pawl) into a single integrated assembly that shares common components including the movable handle, central shaft, and housing. This merging reduces the overall number of parts and simplifies the structure while maintaining bidirectional rotation control capability, directly addressing the complexity issue of traditional one-way pawl mechanisms
Solution Approach 2:
The movable handle serves multiple functions: it acts as a lever for both clockwise and counterclockwise rotation control, functions as a reset mechanism through the reset spring, and provides structural support for both pawls. This multi-functionality reduces the need for separate components, thereby simplifying the overall mechanism structure
2Ease of operation
If a pawl braking mechanism is used for one-way rotation control, then the seat height can be adjusted, but the mechanism occupies large space
Solution Approach 1:
The first pawl and second pawl are nested within the same housing space, sharing common structural elements. The movable handle and central shaft are positioned concentrically, and the reset spring is nested within the handle's inner hole. This nested arrangement maximizes space utilization and minimizes the overall volume occupied by the mechanism
Solution Approach 2:
By merging the two pawl mechanisms into a single integrated assembly with shared components (housing, central shaft, movable handle), the patent reduces the total space required compared to having separate one-way mechanisms, directly addressing the space occupation issue
3Device complexity
If a one-way rotating mechanism is used, then the structure is simpler, but it requires re-adjustment if the optimal height is missed
Solution Approach 1:
The patent implements dynamic bidirectional rotation control where the mechanism can switch between clockwise and counterclockwise rotation based on the direction of applied force. The movable handle can be pushed or pulled in either direction, and the corresponding pawl engages to drive the ratchet wheel in the desired direction, providing operational flexibility that eliminates the need for resetting
Solution Approach 2:
The reset spring automatically returns the movable handle to its initial position after each adjustment operation, whether clockwise or counterclockwise. This self-service reset function eliminates the need for manual resetting and allows users to continue adjusting in the opposite direction if the optimal height is missed, significantly improving adjustment convenience
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 device allows for convenient, bidirectional adjustment of seat height with a simple structure and minimal space occupation, ensuring secure engagement and disengagement of ratchet teeth, facilitating precise height control and easy operation.
Implementation Method 1
A handle reset spring is disposed at an inner hole of the ratchet wheel, a first free end and a second free end of the handle reset spring are placed in a fourth sliding slot of the fixed casing after passing through a third sliding slot of the movable handle
Implementation Method 2
A pawl reset spring is connected with the first boss, the second boss and the central shaft, such that the first tooth section and the second tooth section have a tendency to move toward ratchet teeth of the ratchet wheel
Implementation Method 3
the tooth section of one of the first pawl and the second pawl is engaged with the ratchet teeth, the tooth section of the other is disengaged from the ratchet teeth, whereby the ratchet wheel is driven to rotate synchronically
Data Source
AI summary
A bidirectional driving device includes a ratchet wheel, a movable handle, a fixed casing, a pawl reset spring, a handle reset spring and a central shaft. The handle reset spring is in an inner hole of the ratchet wheel. A positioning column of the handle reset spring is placed in sliding slots of the movable handle and of the fixed casing. First and second pawls are disposed between the ratchet wheel and the movable handle. Tooth sections of the first and second pawls are engaged with ratchet teeth of the ratchet wheel. Positioning columns of the first and second pawls are connected with the movable handle. Bosses of the first and second pawls are placed in sliding slots of the fixed casing, each composed of two circular arc slot sections with different radius. The pawl reset spring is connected with the bosses and with the central shaft.