Linear Terminal Temperature Switch Prevents High Voltage Short Circuits
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Solution Overview
Problem
Conventional temperature switches with bimetal elements, designed for low voltages, face challenges when used in high-voltage applications like hairdryers, as they can lead to short circuits due to small terminal clearances, making them unsuitable for compact electric devices.
Innovation Solution
A compact temperature switch design featuring a first and second terminal unit arranged in line, with insulation material, a movable plate, and a bimetal element, where the movable plate and bimetal element work together to ensure safe passage or breaking of large currents without short circuits, maintaining a compact form factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the distance between terminals is increased to prevent short circuits at high voltage, then safety is improved, but the overall configuration becomes larger and cannot be embedded in compact electric devices
Solution Approach 1:
The patent transitions from a parallel terminal arrangement to a series terminal arrangement, changing the spatial dimension of terminal placement. This dimensional change allows terminals to be positioned end-to-end rather than side-by-side, achieving adequate clearance for high voltage safety while maintaining a compact overall switch configuration that can be embedded in small electric devices.
Solution Approach 2:
The patent inverts the conventional parallel terminal arrangement by adopting a series arrangement where terminals are positioned at opposite ends of the switch body. This inversion of the terminal configuration approach resolves the contradiction by achieving both safety clearance and compact size through a fundamentally different spatial organization.
2Loss of energy
If the current-passing direction is turned back at the contact part to minimize internal resistance, then heat generation is reduced, but the terminal arrangement requires parallel configuration which increases short circuit risk at high voltage
Solution Approach 1:
The patent inverts the conventional current path configuration by arranging terminals in series rather than parallel. This inversion changes the current flow direction from turning back at contacts to flowing linearly through the switch body, eliminating short circuit risk while maintaining acceptable heat generation through proper contact design.
Solution Approach 2:
The patent segments the switch into distinct functional units: terminal units, insulation units, and contact units. This segmentation allows the current path to be optimized for low resistance in the contact region while maintaining safe clearance in the terminal region, resolving the contradiction between heat generation and short circuit prevention.
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 effectively prevents short circuits at high voltages, allows for compact integration in small electric devices, and minimizes heat generation, ensuring reliable operation across varying temperatures.
Implementation Method 1
a bimetal element... inverts a bending-back direction into a shape that is concave in each contact direction when the movable contact opens... and inverts a bending-back direction into a shape that is convex in each contact direction when the movable contact closes
Implementation Method 2
includes a spring property of bending backward the movable contact in a direction in which the movable contact moves away from the first fixed contact and the second fixed contact
Data Source
AI summary
A temperature switch 1 includes first terminal unit 2 having a first terminal 5 and a first fixed contact 6, a switch body unit 3 including a bimetal element 22 in which both ends engage a movable plate 15 holding, via an tongue portion 17, first and second fixed contacts 6 and 8 arranged in an internal center portion of an insulation material 10 at prescribed intervals and also holding a movable contact 18 arranged above them, and a second terminal unit 4 having a second terminal 7 and the second fixed contact 8. The first terminal unit 2, the switch body unit 3, and the second terminal unit 4 are sequentially arranged in line. At an ambient temperature, the bimetal element 22 deforms into a convex shape in the contact direction so as to push out the tongue portion 17 and the movable contact 18 at the center of the convex shape, and the movable contact 18 is closed with respect to the first and second fixed contacts 6 and 8 so that a current flows between the first and second terminals 5 and 7. At an ambient temperature equal to or higher than a prescribed value, the bimetal element 22 causes inversion to become concave in the contact direction, releases the biasing force of the spring property toward the space above the tongue portion 17, the movable contact 18 moves away from the first and second fixed contacts 6 and 8, and a current is cut off.