Chair Armrest Socket With Swaged Tube Anti-Rotation Mount
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Solution Overview
Problem
Existing armrest connections to tubular chair frames lack a secure anti-rotation mechanism and require additional components for assembly, leading to instability and complexity in mounting.
Innovation Solution
A swaged, non-circular frame tube end with a four-lobed shape and central bore is used to create a self-tapping thread connection with the armrest, preventing rotation and securing it mechanically without additional parts, utilizing a downward-opening socket and self-threading fastener for a simple and stable assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional circular frame tube end is used, then the manufacturing process is simple, but the armrest can rotate and the connection is unstable
Solution Approach 1:
The frame tube end is transformed from a symmetric circular cross-section to an asymmetric non-circular shape with four lobes and channel-like recesses. This asymmetric geometry prevents rotation of the armrest by creating a unique orientation fit with the corresponding socket, while the swaging process integrates this complex shape directly into the tube end without requiring separate components.
2Reliability
If additional components are added to secure the armrest, then the connection reliability improves, but the assembly complexity increases
Solution Approach 1:
The invention merges multiple functions into the frame tube end structure itself. The non-circular swaged shape simultaneously provides anti-rotation capability and structural support, while the integrated central bore and recesses eliminate the need for separate anti-rotation pins or additional fastening components. The socket with corresponding geometry combines positioning and securing functions in a single element.
Solution Approach 2:
The swaged frame tube end structure is self-sufficient in providing both anti-rotation and securing functions without requiring external components. The geometry of the lobes and recesses automatically prevents rotation when the armrest is installed, and the self-tapping fastener utilizes the integrated central bore for thread engagement, making the system self-contained and reducing assembly complexity.
3Stability of the object's composition
If a non-circular swaged shape is created, then anti-rotation is achieved, but the manufacturing process becomes more complex
Solution Approach 1:
The invention changes the geometric parameters of the frame tube end by applying a swaging process that transforms the circular cross-section into a non-circular shape with four lobes. This parameter transformation is achieved through controlled deformation during manufacturing, creating the anti-rotation geometry directly in the tube end without requiring post-processing or additional components.
Data Source
AI summary
An armrest for a chair is provided which has an improved anti-rotation and mechanical connection between an armrest body and a frame tube of the chair. The end of the frame tube is mechanically deformed or is shaped so as to have a non-circular profile with a central opening defined by inwardly projecting arcuate surfaces of the frame tube. The armrest includes a cooperating, non-circular socket which fits onto the frame tube wherein a suitable fastener is threaded downwardly into direct, self-threading engagement with an upper opening formed in the end of the frame tube.