Cooktop Knob Assembly with Joint for Misalignment Tolerance
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Solution Overview
Problem
Existing cooking appliance knobs face issues with misalignment due to assembly tolerance, leading to operational failures and aesthetic defects, and lack a reliable mechanism for fine adjustment of gas flow rate without separate components, compromising safety and user convenience.
Innovation Solution
A knob assembly with a joint that absorbs positional errors between the knob and valve shafts, featuring a knob ring for independent operation and display, and a Hall sensor system for precise power control, ensuring accurate rotation measurement and reduced risk of gas leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a knob is directly connected to a valve shaft, then the structure is simple, but assembly tolerance causes misalignment and operational failure
Solution Approach 1:
The knob assembly is divided into separate components: a knob body, a valve shaft, and a coupling mechanism. The knob body rotates independently while the valve shaft transmits motion to the valve, allowing tolerance compensation at the coupling interface rather than requiring perfect alignment throughout the entire assembly.
Solution Approach 2:
A coupling mechanism acts as an intermediary between the knob body and valve shaft. This intermediary component absorbs positional errors and misalignments through its own degrees of freedom or compliant features, ensuring reliable power transmission without requiring precise alignment between the knob and valve shaft.
2Object-affected harmful factors
If a knob is pressed and rotated for safety, then gas leakage is prevented, but the operation becomes more complex
Solution Approach 1:
The knob assembly transitions from a static connection to a dynamic push-rotate mechanism. The knob body can be pushed axially to engage or disengage the coupling with the valve shaft, and rotated to control the valve. This dynamic operation ensures gas leakage prevention through the push action while maintaining ease of operation through the intuitive rotate action.
Solution Approach 2:
The coupling mechanism automatically engages or disengages based on the push-rotate operation of the knob body. The design ensures that the knob must be pushed to establish coupling with the valve shaft, and the rotation automatically transmits motion only when properly engaged, providing self-verifying safety without requiring additional components or complex procedures.
3Manufacturing precision
If a joint absorbs position error, then alignment is improved, but the device complexity increases
Solution Approach 1:
The joint mechanism changes the operational parameters of the connection between knob and valve shaft. It introduces axial movement freedom and rotational coupling that allows positional errors to be compensated through parameter variation rather than requiring fixed precise alignment. The joint transforms rigid alignment requirements into flexible parameter-adjustable connections.
4Measurement precision
If fine adjustment of gas flow is enabled, then control precision is improved, but additional components are required
Solution Approach 1:
The knob body serves multiple functions: it acts as the user interface for operation, transmits rotational motion to the valve shaft, and provides fine adjustment capability through its coupling mechanism. The same rotational motion that controls valve opening also enables fine adjustment of gas flow rate, eliminating the need for separate adjustment components while maintaining control precision.
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
The solution stabilizes knob operation, enhances appearance quality, and provides precise control over gas flow, improving safety and user convenience by preventing misalignment and allowing fine adjustments without additional components, thus reducing the risk of accidents and operational defects.
Implementation Method 1
a Hall sensor system for precise power control, ensuring accurate rotation measurement
Data Source
AI summary
A knob assembly includes a front panel, a knob located at a front side of the front panel and configured to rotate based on operation by a user, a knob shaft that is coupled to the knob and that extends through the front panel, a supporting pipe that receives the knob shaft and that supports the knob shaft, the supporting pipe being configured to maintain a position relative to the front panel, a valve configured to control supply of gas to the appliance, a valve shaft connected to the valve and configured to control the valve to adjust a flow rate of gas based on rotation of the valve shaft, and a joint that couples the knob shaft to the valve shaft and that is configured to transfer at least one of a rotational motion or a linear motion of the knob shaft to the valve shaft.