Tilt Switch Frusto-Conical Chamber Prevents Rolling Element Sticking
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Solution Overview
Problem
Conventional tilt switches with cone angles less than or equal to 90 degrees experience sticking issues due to annular contact between the rolling element and the bottom inner wall surface, hindering smooth ON/OFF switching.
Innovation Solution
A tilt switch design featuring a housing with a frusto-conical inner wall surface and a tapered bottom inner wall surface, where the first cone angle is greater than 90 degrees and the second cone angle is less than or equal to 90 degrees, allowing the rolling element to roll smoothly between blocking and unblocking positions without getting stuck.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cone angle is less than or equal to 90 degrees, then the safety requirement is met, but the rolling element gets stuck due to annular contact with the bottom inner wall surface
Solution Approach 1:
The inner wall surface is segmented into two distinct zones: a upper frusto-conical surface with cone angle ≤90° for safety, and a lower tapered surface with cone angle >90° to prevent sticking. This segmentation allows each zone to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the inner wall surface are given different geometric properties (cone angles). The upper portion has a shallower angle for safety while the lower portion has a steeper angle for smooth operation, creating local quality variations that solve the global contradiction.
2Reliability
If the cone angle is less than or equal to 90 degrees, then the safety requirement is met, but the rolling element cannot roll smoothly due to clamping by the bottom inner wall surface
Solution Approach 1:
The inner wall surface is divided into two functional zones with different cone angles, allowing the rolling element to experience appropriate gravitational and normal forces in each zone for both safety and smooth rolling motion.
Solution Approach 2:
The cone angle parameter is varied along the axial direction of the chamber, transitioning from ≤90° in the upper region to >90° in the lower region, thereby changing the mechanical interaction characteristics to prevent clamping while maintaining safety.
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
Enhances the sensitivity and smooth operation of the tilt switch by preventing clamping and sticking, ensuring reliable ON/OFF switching without the rolling element getting stuck to the tapered bottom inner wall surface.
Implementation Method 1
The rolling element is disposed in the chamber, and is rollable along the tapered bottom inner wall surface and the frusto-conical inner wall surface between a blocking position that blocks the light emitted from the light emitter, and an unblocking position that unblocks the light emitted from the light emitter
Implementation Method 2
When the housing 11 is subjected to an external force and is tilted to an angle that is equal to or greater than an inclination angle (α), the ball 4 will roll away from the bottom inner wall surface 111
Implementation Method 3
The light emitter and the light receiver cooperatively define an optical axis. Light emitted from the light emitter travels along the optical axis and passes through the chamber toward the light receiver
Implementation Method 4
a photoelectric module includes a light emitter and a light receiver disposed respectively at two opposite sides of the chamber
Data Source
AI summary
A tilt switch includes a housing defining a chamber and including a frusto-conical inner wall surface having a cone angle which is less than or equal to 90 degrees, and a tapered bottom inner wall surface that defines a bottom end of the chamber, that tapers downwardly from a bottom end of the frusto-conical inner wall surface and that forms a cone angle which is greater than 90 degrees. A light emitter and a light receiver are disposed respectively at two opposite sides of the chamber. A rolling element is rollable in the chamber between blocking and unblocking positions, where the rolling element blocks and unblocks light emitted from the light emitter, respectively.