Office Chair Back Rest Mounting With Spring-Loaded Pin Locking
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Solution Overview
Problem
Existing office chair assembly processes are cumbersome and inefficient, requiring complex assembly procedures and heavy components, which hinder self-assembly and increase packaging and transport costs.
Innovation Solution
A device featuring a swivel support mechanism with a frusto-conical socket, a pivoted connecting piece, and a spring-loaded pin system that allows the back rest to be easily mounted and rotated, utilizing a hinge mechanism with L-shaped slots and a coil spring for secure locking and quick release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional screw-based coupling is used to securely attach the back rest, then the attachment strength is sufficient, but the assembly process becomes cumbersome and time-consuming
Solution Approach 1:
The coupling mechanism is divided into separate functional elements: a coupling element with engagement protrusions on the back rest, and corresponding engagement recesses on the support box. This segmentation allows for quick snap-fit assembly without requiring threaded fasteners, directly reducing assembly time while maintaining secure attachment.
Solution Approach 2:
The coupling mechanism is designed to be self-aligning and self-securing. The engagement protrusions automatically guide into the recesses during assembly, and the elastic support element provides automatic locking without requiring user intervention for tightening or securing, enabling true self-assembly by the final user.
2Ease of manufacture
If components are designed for separate shipping to reduce packaging costs, then packaging efficiency improves, but assembly complexity increases
Solution Approach 1:
The chair is deliberately segmented into separable components (support box, back rest, seating portion, column, spokes) that can be shipped independently. The coupling mechanisms are designed with standardized interfaces that simplify the reassembly process, turning what could be complex into a straightforward sequence of alignment and engagement actions.
Solution Approach 2:
The coupling elements are designed with universal characteristics - the same coupling principle is applied to multiple joints (back rest to support box, seating portion to support box, column to support box). This universality means users learn one assembly pattern that applies to all connections, reducing overall assembly complexity despite multiple separate components.
3Ease of operation
If the back rest is made rotatable for user comfort, then ergonomics improve, but the mounting mechanism becomes more complex
Solution Approach 1:
The rotational movement function and the mounting function are merged into a single integrated mechanism. The coupling element serves both to securely attach the back rest and to enable its rotation. The elastic support element provides both the locking force for secure mounting and the controlled resistance for smooth rotation, eliminating the need for separate mounting and rotation mechanisms.
Solution Approach 2:
The mounting mechanism transitions from a static fixed connection to a dynamic connection that allows controlled rotation. The elastic support element enables the back rest to rotate through a range of positions while maintaining secure attachment, providing ergonomic adaptability without requiring complex mechanical linkages or actuators.
4Strength
If heavy-duty screws are used to secure components, then structural strength is maintained, but component weight increases
Solution Approach 1:
The traditional mechanical screw-and-thread system is replaced with a snap-fit coupling mechanism using elastic deformation and geometric interlocking. The engagement protrusions and recesses create secure attachment through elastic support and geometric constraints, eliminating the need for heavy metal fasteners and significantly reducing component weight while maintaining adequate attachment strength for office chair applications.
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 rapid and easy assembly/disassembly of office chairs, reducing component weight and size, facilitating efficient self-assembly, cost-effective packaging, and simplified transport while ensuring secure attachment of the back rest.
Implementation Method 1
a spring-loaded pin system that allows the back rest to be easily mounted and rotated, utilizing a hinge mechanism with L-shaped slots and a coil spring for secure locking
Data Source
AI summary
A device for connecting a back rest to the seating portion support mechanism for chairs includes a first part pertaining to the mechanism, a second part pertaining to the back rest, a pair of pins, at least one of which is applied to the first part (second part), a pair of open slots, at least one of which pertains to the second part (first part), the slots forming housings for the pins, an elastic member acting on at least one of the pins or the housings, the distance between the axes of the pins or the housings being modifiable temporarily against the action of the elastic member, wherein the open slots present an inclined surface which, by acting against one of the pins, causes a temporary modification of the distance between axes of the pins, so facilitating engagement of the pin in the housing seat.