Adjusting mechanism and chair including the same
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Solution Overview
Problem
Existing chair adjusting mechanisms for setting restoring forces on backrests are complex, costly, and difficult to assemble, lacking a simple and durable configuration that can be easily adjusted for users of different weights.
Innovation Solution
A novel adjusting mechanism comprising a mounting frame, pivot axle, force varying unit, biasing unit, and switching unit, which allows the backrest to be angularly movable between normal and inclined positions with varying restoring forces, utilizing a cam member and spring segment to generate different restoring forces for returning the backrest to its normal position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional adjusting mechanisms with scissor arms and multiple pivot points are used, then the restoring force can be adjusted, but the device complexity increases and assembly becomes difficult
Solution Approach 1:
The mechanism is divided into distinct functional modules: a mounting frame for structural support, a force varying unit with cam member for restoring force adjustment, a biasing unit with spring segment for providing biasing force, and a switching unit with follower end for position switching. Each module performs a specific function, simplifying the overall design while maintaining adjustability capabilities.
Solution Approach 2:
The complex scissor arm mechanism with multiple pivot points is extracted and replaced with a simplified cam-based force varying unit. The cam member directly varies the restoring force without requiring multiple linked arms and joints, significantly reducing structural complexity while preserving the force adjustment functionality.
2Adaptability or versatility
If conventional adjusting mechanisms with multiple components are used, then the restoring force can be adjusted, but the manufacturing cost increases
Solution Approach 1:
The mechanism uses standardized modular components that can be manufactured independently and assembled. The mounting frame, force varying unit, biasing unit, and switching unit are separate assemblies that can be produced using standard manufacturing processes, reducing tooling costs and simplifying production.
Solution Approach 2:
The complex scissor arm mechanism is replaced with simpler cam and spring components that have fewer parts and require less precision machining. The cam member can be manufactured as a single piece or simple assembly, and the spring segment is a standard elastic component, both of which are more cost-effective to produce than multi-component mechanical linkages.
3Adaptability or versatility
If conventional adjusting mechanisms with multiple pivot points are used, then the restoring force can be adjusted, but the assembly process becomes time-consuming
Solution Approach 1:
The mechanism is designed as pre-assembled modular units (mounting frame, force varying unit, biasing unit, switching unit) that can be manufactured and tested separately before final assembly. This modular approach allows parallel production of components and simplifies the final assembly process, improving overall productivity.
Solution Approach 2:
The complex network of scissor arms, pivot points, and connecting joints is extracted and replaced with a streamlined cam-based system. The force varying unit attaches directly to the mounting frame, and the switching unit connects straightforwardly to the biasing unit, eliminating the need for assembling multiple linked components and significantly reducing assembly time.
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 mechanism provides a simple, durable, and cost-effective way to adjust restoring forces on a chair backrest, allowing for user-specific settings with easy assembly and manufacturing, enabling efficient movement between normal and inclined positions with adjustable restoring forces.
Implementation Method 1
The spring segment is disposed between the head end and the follower end in the accommodation space to bias the follower end to the remote position, and is configured to keep the follower end to be in pressing engagement with the cam surface by a first biasing force when the follower end is in the distal position or by a second biasing force when the follower end is in the proximate position
Implementation Method 2
The cam member is disposed below the pivot axle and between the lugs, and has a cam surface disposed to face forwardly and having a distal region and a proximate region relative to the pivot axle
Data Source
Figure 1
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AI summary
An adjusting mechanism (300) is provided for selectively setting a restoring force acting on a backrest (200) of a chair (1) . In a biasing unit (510) of the adjusting mechanism (300), a spring segment (513) is disposed between a head end (514) and a follower end (515) to bias the follower end (515) to the remote position. The follower end (515) is angularly movable on a cam surface (471) between distal and proximate positions. In response to movement of a backrest (200) of the chair (1) from a normal position to an inclined position to permit the follower end (515) to be forced by the cam surface (471) to move from the remote position to a close position, two different restoring forces can be set by adjusting the follower end (515) between the distal and proximate positions.