Rotary Knob Assembly with Integrated Molded Shaft and Shell Ring
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Solution Overview
Problem
The existing rotary knobs in household appliances are complex, costly to manufacture, prone to dismantling, and lack a secure connection, leading to user safety concerns and increased production costs.
Innovation Solution
A rotary knob assembly is created by molding a knob shaft and shell ring portion together using over injection molding, eliminating additional assembly steps and providing a robust, secure connection, reducing material usage, and enhancing durability and user safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple layers and materials are used in the rotary knob, then the structural complexity increases, but the manufacturing cost increases and assembly operations become more numerous
Solution Approach 1:
The patent combines multiple separate components (knob body, cap, and socket) into a single integrated rotary knob structure. The cap is formed as an integral part of the knob body, eliminating the need for separate assembly operations and reducing the number of layers while maintaining connection security through the unified structure.
Solution Approach 2:
The integrated rotary knob structure serves multiple functions simultaneously: the knob body provides the rotational control function, the integrated cap provides the user interaction surface, and the unified structure provides both mechanical support and connection security, eliminating the need for separate components with dedicated functions.
2Ease of manufacture
If snap fitting or gluing is used to assemble the cap to the socket, then the assembly process is simple, but the connection is prone to dismantling after many uses
Solution Approach 1:
The cap and socket are merged into a single integral component through injection molding, eliminating the need for separate assembly processes like snap fitting or gluing. This unified structure ensures permanent connection durability while maintaining ease of manufacture through a single-mold manufacturing process.
Solution Approach 2:
The patent uses injection molding to create a permanent, non-disassemblable structure that eliminates the need for expensive assembly processes or materials. The integrated design ensures the connection lasts the lifetime of the appliance without requiring replacement or reassembly.
3Adaptability or versatility
If multiple separate components are used in the rotary knob, then the design flexibility increases, but the production costs increase due to multiple assembly operations
Solution Approach 1:
The patent merges multiple components into a single injection-molded part, which maintains design flexibility through the molding process itself while dramatically improving production efficiency by eliminating multiple assembly operations. The integrated structure can still incorporate various design features through mold design variations.
4Ease of manufacture
If separate components are assembled using conventional methods, then the manufacturing process is established, but additional fastening steps and materials are required
Solution Approach 1:
The patent combines multiple components into a single injection-molded part, eliminating the need for additional fastening materials such as adhesives, fasteners, or sealing compounds. The integrated structure uses only the essential material for the knob function, reducing material waste and simplifying the manufacturing process.
Data Source
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AI summary
A rotary knob assembly (3) for assembling to a control panel (2) of a household appliance (1) comprising a knob shaft (31) for assembling to the control panel (2) of the household appliance (1) and a shell ring portion (32) for gripping. As an improvement, the knob shaft (31) and the shell ring portion (32) are molded together.