Cooktop Knob Assembly with Joint to Absorb Shaft Misalignment
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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 separating components.
Innovation Solution
A knob assembly with a joint that absorbs positional errors between the knob and valve shafts, featuring a knob ring with a display device for setting and displaying timer and firepower levels, using a Hall sensor and magnet for precise rotation sensing, and a push-and-turn mechanism to prevent accidental rotation.
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:
A joint is introduced as an intermediary component between the knob and valve shaft. This joint includes a joint body with a first shaft coupling portion connected to the valve shaft and a second shaft coupling portion connected to the knob shaft, serving as a mediator that absorbs assembly tolerance and prevents misalignment while maintaining structural simplicity and operational reliability.
2Ease of operation
If the knob is separated from the valve assembly, then fine adjustment of flow rate is possible, but assembly complexity increases and manufacturing cost rises
Solution Approach 1:
The valve assembly is segmented into distinct components: the valve body, valve shaft, and separately adjustable knob connected via a joint. This segmentation allows the knob to be independently adjusted for fine flow rate control while maintaining a unified structure that does not increase overall assembly complexity or manufacturing cost.
3Manufacturing precision
If a joint is added between knob and valve shaft, then assembly tolerance is absorbed and alignment is improved, but device complexity increases
Solution Approach 1:
The joint serves as a simple intermediary component with standardized shaft coupling portions that connect the valve shaft and knob shaft. Its design is intentionally straightforward, featuring a joint body with basic coupling mechanisms that absorb tolerance without introducing complex adjustment mechanisms, thereby improving alignment while minimizing added complexity.
4Ease of operation
If the knob can rotate freely, then operation is convenient, but accidental rotation causes gas leakage
Solution Approach 1:
A push button mechanism is implemented that requires the user to press the button before the knob can rotate. This preliminary action creates a mechanical lock that prevents accidental rotation and potential gas leakage, while still allowing intentional operation when needed. The push button must be actuated to release the locking mechanism, ensuring deliberate user action.
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 the knob operation, improves appearance quality, enhances user convenience, and reduces the risk of gas leakage by accurately controlling the gas flow and preventing operational mistakes, while maintaining a compact design and reducing manufacturing costs.
Implementation Method 1
using a Hall sensor and magnet for precise rotation sensing
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.