Chair Backrest Rail Locking Assembly for Tool-Free Adjustment
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Solution Overview
Problem
Existing adjustment devices for chairs, such as those used to adjust the spacing of the backrest relative to the seating surface, require additional tools for assembly and often include complex mechanisms with multiple components, making the process cumbersome and requiring additional resilient elements.
Innovation Solution
The adjustment device features a guide rail, a sliding element, and a locking element that can be retained in multiple positions, allowing the sliding element to be easily inserted during assembly without tools, with the locking element interacting with catches along the adjustment axis to limit movement in one direction, and utilizing a resilient design to eliminate the need for additional resilient elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locking mechanism with multiple components and additional resilient elements is used, then the locking function is reliable, but the device complexity increases and assembly becomes cumbersome
Solution Approach 1:
The locking element combines multiple functions into a single component: it serves as both the locking mechanism and the resilient element. The locking element integrates the locking projection, the resilient body, and the interaction with catches into one unified component, eliminating the need for separate resilient elements and reducing overall device complexity while maintaining reliable locking functionality.
Solution Approach 2:
The locking element is designed as a multi-functional component that performs locking, provides resilient force, and interacts with the sliding element and guide rail. This universal component replaces what would traditionally require multiple specialized parts, simplifying the overall structure while ensuring reliable operation.
2Reliability
If a locking mechanism requiring additional tools for assembly is used, then the locking function is secure, but the ease of manufacture deteriorates
Solution Approach 1:
The locking element is designed to be self-installing through a snap-fit mechanism. The resilient body allows the locking projection to be inserted into the guide rail and automatically engage with the locking groove without requiring additional tools. The element serves itself during assembly by using its own resilient properties to secure itself in place.
3Ease of operation
If the locking element is retained in a locking position during assembly, then the sliding element cannot be introduced, but if retained in an assembly position, then the sliding element can be introduced easily
Solution Approach 1:
The locking element is designed with dynamic positioning capability, allowing it to be temporarily held in an assembly position during installation and then automatically transition to the locking position upon completion of assembly. The resilient body enables the locking projection to be positioned freely during assembly and then snap into the locked state when the sliding element is fully inserted.
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 simplifies the assembly process by allowing the sliding element to be inserted into the guide rail without additional tools, ensuring secure attachment and preventing unintentional withdrawal, while maintaining the ability to adjust the backrest relative to the seat without complex mechanisms.
Implementation Method 1
The locking element (8) is retained on the guide rail (6) in a resilient manner
Data Source
AI summary
The adjustment device according to the invention for an adjustable element, in particular the backrest of a chair, has a guide rail and a sliding element which is movable in the guide rail along an adjustment axis. Furthermore, a blocking element is provided, which blocking element can be secured on the guide rail or on the sliding element in a latching position in which the sliding element can be moved along the adjustment axis at least in one direction between two end positions, wherein the blocking element comes into operative contact with latches spaced apart along the adjustment axis. During the installation of the adjustment device, the blocking element is secured on the guide rail or the sliding element in an installation position in which the sliding element can be introduced into the guide rail in the direction of the adjustment axis.