Eccentric Cam Seat Angle Assembly for Two-Position Chair Tilt
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Solution Overview
Problem
Existing chair control mechanisms do not efficiently allow for the adjustment of seat angle between two distinct positions, such as a horizontal and an inclined position, which can enhance user comfort during long periods of use.
Innovation Solution
A two-position, at rest, seat angle adjustment assembly that includes left and right adjustment mechanisms, a rod, and a lever, utilizing eccentric cams and a J-back adjustment assembly to move the seat between a generally horizontal and an inclined position, with the ability to lock in either position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanism allows seat angle adjustment between two distinct positions, then user comfort is improved, but device complexity increases
Solution Approach 1:
The mechanism employs an eccentric cam that can be rotated to different angular positions, transforming a static seat structure into a dynamic one capable of assuming two distinct angular configurations. The eccentric cam's offset center allows the seat to tilt between horizontal and inclined positions while maintaining structural integrity through controlled movement.
Solution Approach 2:
The invention changes the angular parameter of the seat by rotating the eccentric cam to different positions. By altering the cam's rotational angle, the mechanism transforms the seat's inclination parameter between two fixed states, enabling position adjustment without requiring complex continuous control systems.
2Ease of operation
If the seat can be inclined at an angle for comfort, then user comfort is improved, but manufacturing complexity increases
Solution Approach 1:
The adjustment mechanism is divided into distinct modular components: the eccentric cam, the collar with keyway, the rod, and the lever. Each component can be manufactured separately using standard machining processes, and then assembled together, simplifying both manufacturing and assembly compared to creating a single complex integrated structure.
Solution Approach 2:
Instead of designing a complex mechanism to achieve seat inclination, the invention uses a simple eccentric cam that naturally produces the inclined position through its offset geometry. The inclination is achieved by the inverted approach of using an off-center rotation point rather than a centered pivot, simplifying the overall construction.
3Ease of manufacture
If a simple construction is used to reduce costs, then manufacturing cost is reduced, but adjustment precision may be compromised
Solution Approach 1:
The mechanism uses simple, inexpensive components such as a basic eccentric cam and lever that can be manufactured with standard tolerances. These components, while simple in construction, provide sufficient precision for the two-position adjustment function without requiring high-precision machining or expensive materials.
Solution Approach 2:
The eccentric cam is pre-designed with a specific offset distance that predetermined the exact inclination angle of the seat. This preliminary design of the cam's geometry ensures that when rotated to the inclined position, the seat achieves the precise desired angle without requiring additional adjustment or high-precision control during 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
Enables easy and intuitive adjustment of the seat angle between two positions, providing enhanced comfort and support for users by allowing the seat to be set at a preferred five-degree inclination, while maintaining a simple construction and reducing manufacturing costs.
Implementation Method 1
The cam includes an inner cam and a collar. The inner cam is an eccentric cam that is received in a cam working area.
Implementation Method 2
The lever is utilized to rotate the cams within their respective housings thereby moving the first plate with respect to the J-back assembly.
Data Source
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AI summary
This invention is directed to a two-position, at rest, seat angle adjustment assembly that locks the seat in two distinct positions. In a first position, the seat is generally horizontal, while in a second position, the seat is inclined at an angle relative to horizontal. The assembly includes left and right adjustment mechanisms, a rod, and a lever. The left and right adjustment mechanisms are mounted to the seat and the back assembly on each side thereof. Each of the mechanisms includes a housing, and a cam. The cam is received in the housing and the rod is fixably received within the cam. The lever is attached to the rod proximate the right adjustment mechanism. The lever is utilized to rotate the cams within their respective housings thereby moving the seat with respect to the back assembly.