Chair T-Nut Fastening for Thin Substrate Retention
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Solution Overview
Problem
The use of T-nuts in chair manufacturing is limited by the thickness of the structure they are attached to, leading to displacement and loosening issues when fasteners are inserted, which can result in manufacturing problems and potential issues for chair purchasers due to insufficient attachment strength.
Innovation Solution
A method involving a substrate with holes for receiving T-nuts, where the T-nut projections are inserted and then bent into the substrate to increase grip, allowing standard T-nuts to be securely attached to thinner substrates, enabling the use of standard fastening devices while reducing manufacturing issues and providing broader design options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If T-nuts are used to attach skin components to frame components, then standard fastening devices can be used for assembly, but the T-nuts become displaced or loosened when fasteners are inserted due to insufficient structure thickness
Solution Approach 1:
The method applies preliminary action by bending the projections of the T-nut into the substrate before the fastener is inserted. This pre-deformation creates sufficient grip strength in advance, preventing the T-nut from becoming displaced or loosened during subsequent fastener insertion, thereby resolving the reliability issue while maintaining ease of manufacture
Solution Approach 2:
The invention changes the physical state and geometric parameters of the T-nut projections by deforming them from a straight configuration to a bent configuration that extends into the substrate. This parameter change increases the contact area and mechanical interlocking strength, enabling reliable attachment even in thin substrates where conventional T-nuts would fail
2Strength
If T-nuts with barbs are used to attach to thin structures, then fastening can be achieved, but the structure thickness becomes a limiting factor increasing fabrication costs and minimizing design options
Solution Approach 1:
By changing the geometric parameters of the projections through bending deformation, the invention achieves sufficient fastening strength in thin structures without requiring increased substrate thickness. This enables broader design options including thinner seat skins and back skins while maintaining reliable attachment
Solution Approach 2:
The invention utilizes the third dimension by bending projections into the substrate thickness direction, creating mechanical interlocking within the available thickness. This dimensional approach allows effective fastening in thin structures without constraining design freedom or increasing material costs
3Productivity
If T-nuts are inserted into thin substrates without projection bending, then assembly can proceed, but dislodgement occurs during fastener insertion due to insufficient grip
Solution Approach 1:
The projection bending step is performed as a preliminary action before fastener insertion. This pre-deformation ensures reliable T-nut retention is established in advance, preventing dislodgement during the assembly process while maintaining overall productivity through a simple, integrated manufacturing step
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 method ensures that T-nuts remain affixed during assembly, providing sufficient attachment strength to withstand torque and axial forces, preventing dislodgement and enhancing the reliability of chair components, thus reducing maintenance needs and improving chair desirability.
Implementation Method 1
The distal ends of the projections are bent into the substrate
Data Source
AI summary
A method of making a chair includes the steps of providing at least one female fastener device. The at least one female fastener device is inserted into a substrate for attaching the at least one female fastener device to the substrate such that at least a portion of that female fastener device's body defining a channel extends into the substrate and the projections extend through the substrate such that the distal ends of the projections extend beyond a second side of the substrate that is opposite a first side of the substrate. The distal ends of the projections are bent into the second side of the substrate. At least one male fastener is inserted into the channel of the at least one female fastener device to attach a chair component to the substrate.