Cooktop Knob Assembly with Joint for Misalignment Absorption
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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 for independent operation and a sensor system using Hall sensors for precise power control and display, ensuring accurate rotation measurement and improved safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a knob is directly connected to a valve assembly, then the structure is simple, but assembly tolerance causes misalignment and operational failure
Solution Approach 1:
A joint component is introduced as an intermediary between the knob and valve assembly. This joint includes a first coupling portion connected to the valve shaft and a second coupling portion connected to the knob shaft, with a joint spring that allows for positional adjustment. The intermediary joint absorbs assembly tolerances and misalignments, preventing operational failures while maintaining overall structural simplicity.
2Manufacturing precision
If a joint with spring is used to connect knob shaft and valve shaft, then assembly tolerance is absorbed, but device complexity increases
Solution Approach 1:
The joint incorporates a spring mechanism that provides dynamic adjustment capability. The joint spring can elastically deform to accommodate positional variations between the knob shaft and valve shaft, allowing the connection to adapt to assembly tolerances rather than requiring rigid precision alignment. This dynamic element absorbs position errors effectively.
3Ease of manufacture
If the knob structure is fixed, then manufacturing is easy, but fine adjustment of gas flow rate is not possible
Solution Approach 1:
The knob system is segmented into multiple functional components: a main knob for primary operation, a separate adjustment mechanism within the joint for fine-tuning gas flow rate, and a sensor system for precise measurement. This segmentation allows the main knob to remain simple for easy manufacturing, while the segmented adjustment mechanism provides the necessary adaptability for fine flow rate control.
4Measurement precision
If a sensor system is added for precise rotation measurement, then control precision is improved, but device complexity increases
Solution Approach 1:
The patent employs sensors (such as Hall sensors or optical encoders) to replace complex mechanical measurement mechanisms. These electronic sensors can accurately detect rotation amount and position with minimal mechanical components, achieving high measurement precision while actually reducing overall mechanical complexity compared to traditional mechanical measurement systems.
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, reducing the risk of gas leakage and improving user convenience while maintaining the appliance's reliability and safety.
Implementation Method 1
a joint spring that allows the knob shaft to couple to the valve shaft regardless of deviation of at least one of the knob shaft or the valve shaft from a coaxial direction
Implementation Method 2
a sensor system using Hall sensors for precise power control and display
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.