Fastenerless Armrest Pad Attachment Using Interlocking Profiles
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Solution Overview
Problem
Conventional armrests for chairs require external fasteners, adhesives, or welding to attach arm pads, which can be cumbersome and limit design flexibility.
Innovation Solution
The armrest system employs interlocking profiles between the arm pad and the armrest structure, utilizing resilient projections and apertures for a fastenerless connection, allowing for interference fit without mechanical tools, adhesives, or welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external fasteners, adhesives, or welding are used to attach arm pads, then the connection strength and reliability are improved, but the device complexity and ease of manufacture deteriorate
Solution Approach 1:
The arm pad and armrest structure are merged into a single integrated component through injection molding, eliminating the need for separate fasteners, adhesives, or welding mechanisms. The arm pad is formed as an integral part of the armrest assembly, reducing device complexity while maintaining connection strength through the unified structural design.
Solution Approach 2:
The armrest structure serves multiple functions: it provides structural support, defines the mounting interface, and integrates the arm pad attachment all in one component. The injection-molded armrest structure incorporates built-in attachment features that combine fastening, positioning, and structural support functions into a single universal component.
2Reliability
If external fasteners, adhesives, or welding are used to attach arm pads, then the connection strength is improved, but the ease of operation and manufacturing time deteriorate
Solution Approach 1:
The arm pad and armrest are combined into a single injection-molded piece, eliminating multiple attachment steps (fastening, adhesiving, or welding) and enabling one-step manufacturing. This integration dramatically improves productivity by reducing assembly operations while ensuring reliable attachment through the molded-in design.
Solution Approach 2:
The attachment features are pre-formed during the injection molding process itself, rather than requiring subsequent assembly steps. The arm pad and armrest structure are created with integrated attachment geometry built-in from the start, eliminating the need for separate fastening operations and improving manufacturing efficiency.
3Reliability
If conventional fastening mechanisms are used, then the connection reliability is improved, but the design flexibility and adaptability deteriorate
Solution Approach 1:
The arm pad and armrest structure are merged into a custom-integrated design specific to each chair configuration. The injection molding process allows for tailored geometries and attachment features that are optimized for particular applications, enhancing design flexibility while ensuring reliable attachment through the customized integrated structure.
Solution Approach 2:
The armrest structure incorporates locally-optimized features at specific positions, such as varying wall thicknesses, reinforcement ribs, and position-specific attachment geometries. This allows the design to be adapted to different mounting locations and configurations while maintaining reliable attachment at each location through locally-tailored structural properties.
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 secure, tool-free attachment of arm pads to armrest supports, enhancing design flexibility and user convenience while eliminating the need for fasteners or adhesives.
Implementation Method 1
Each of the projections can be configured to resiliently deform for insertion into the opening mouth of the recess of the wall of the arm pad to which the projection is inserted so that resiliency of the projection causes the projection to help provide an interference fit connection between the projection and the wall of the arm pad
Data Source
AI summary
A chair can include armrest apparatuses. Each of the armrest apparatuses can be configured so an arm pad is connectable to an armrest without the use of a mechanical fastener (e.g. a screw, a bolt, etc.) and without the use of an adhesive or welding, and without the use of mechanical tools (e.g. screw driver, hammer, etc.) by use of interlocking mating profiles defined in the structure of the arm pad and structure of the armrest to which the arm pad is attached. Embodiments of the chair can be configured as a side chair, task chair, or other type of chair having at least one armrest or other type of armrest apparatus.