Key Switch Linkage Structure With Shared Bridge Circuits
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Solution Overview
Problem
Existing key switches with five keys require multiple bridge circuits and wire connections, leading to complex structural characteristics and increased costs due to the need for numerous wire connections for achieving low and high speed gears.
Innovation Solution
A linkage structure for a key switch featuring a self-locking assembly, linkage assembly with connecting rods, input assembly with a fuse, and output assembly with bridge metal domes and a diode, allowing shared bridge circuits between keys and reducing the number of bridges, thus simplifying connections and lowering costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple independent bridge circuits are used for each gear position, then the circuit functionality is complete, but the structural complexity and cost increase
Solution Approach 1:
The patent merges multiple independent bridge circuits into a shared bridge circuit structure. The first and second bridge metal domes serve common contact pieces that are shared across multiple gear positions, allowing the same bridge circuit to be used for both the second/fourth keys and third/fifth keys. This combining approach maintains complete circuit functionality while significantly reducing structural complexity and the number of required components.
Solution Approach 2:
The bridge metal domes and common contact pieces are designed to serve multiple functions simultaneously. The first common contact piece serves as a contact point for both the first and second bridge metal domes, while the second common contact piece serves both the third and fourth bridge metal domes. This multi-functionality allows a single bridge circuit structure to support multiple gear positions, reducing overall device complexity while maintaining reliability.
2Adaptability or versatility
If wire connections are used to connect keys at the periphery, then the bridge circuits can achieve linked output, but the number of wire connections and costs increase
Solution Approach 1:
The patent extracts and eliminates the need for peripheral wire connections by integrating the linkage function directly into the internal mechanical structure. The linkage assembly with connecting rods mechanically links the push rods for different gear positions, allowing the bridge circuits to achieve linked output through the mechanical movement of keys rather than through external wire connections. This extraction of the wiring function reduces the quantity of wires needed while maintaining the adaptability for linked output.
Solution Approach 2:
The linkage assembly acts as an intermediary mechanism between the keys and the bridge circuits. Instead of using wires to connect keys at the periphery, the linkage assembly with connecting rods serves as a mechanical mediator that transmits the pressing action from one key to another, enabling linked output capability without requiring extensive wire connections.
3Ease of operation
If five independent bridge circuits are used for five keys, then each key has independent control, but the number of bridges and costs increase
Solution Approach 1:
The patent combines five potential independent bridge circuits into a fewer number of shared bridge circuits. The first bridge metal dome and second bridge metal dome share common contact pieces, reducing the total number of bridges from five to two while maintaining independent control capability. Each key can still be controlled independently through the linkage mechanism that translates key presses into corresponding bridge circuit activations.
Solution Approach 2:
The bridge metal domes are designed with multi-functionality to serve multiple keys. The first bridge metal dome can be activated by either the second or fourth key through the linkage mechanism, and the second bridge metal dome can be activated by either the third or fifth key. This universal design reduces the number of bridges needed while preserving independent control ease of operation and reducing manufacturing costs.
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 linkage structure enables shared bridge circuits between keys, reducing wire connections and overall costs while maintaining circuit functionality, achieving efficient and cost-effective design.
Implementation Method 1
a diode is usually used for regulating speed at the high speed gear and the low speed gear. The low speed gear and the low speed inching gear achieve a low speed through rectified output of the diode.
Implementation Method 2
a first bridge metal dome arranged on one side of the first connecting rod, a second bridge metal dome arranged on one side of the second connecting rod
Data Source
AI summary
The present invention relates to a linkage structure of a key switch. A second key and a fourth key share one bridge and are connected by a first connecting rod. When the second key or the fourth key is pressed down, the first connecting rod is pushed, so that a first bridge metal dome deforms and is connected to a common contact piece for conduction. A third key and a fifth key share one bridge and are connected by a second connecting. When the third key or the fifth key is pressed down, the second connecting rod is pushed, so that a second bridge metal dome deforms and is connected to the common contact piece for conduction. An input terminal is connected in series to a fuse, and the second key and the fourth key are connected in series to a diode so as to output a rectification half-wave.