Low-Profile Multi-Directional Key Switch with Spiral Elastic Element
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Solution Overview
Problem
Existing multi-directional key switch designs, such as those described in U.S. Patent Application Publication No. 2008/0048649, suffer from accidental dome switch activation due to the weight of the key cap, magnetic element, and elastic element, leading to incorrect signal transmission.
Innovation Solution
A low-profile multi-directional key switch structure featuring a magnetic element, a key cap, an elastic element with a spiral structure, and a protection pad, which alleviates the weight pressure on the dome switch by allowing the elastic element to adjust its spiral structure and providing a protection pad to prevent interference, thereby reducing accidental activations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a soft elastic element with excellent elasticity is used to provide restoring force, then the key cap can return to original position effectively, but the weight of the elastic element continuously applies pre-existed downward pressure on the dome switch, causing accidental activation
Solution Approach 1:
The elastic element is segmented into a spiral structure with multiple coils, distributing the weight-bearing function across multiple segments rather than a single continuous element, reducing concentrated pressure on the dome switch
Solution Approach 2:
A protection pad is introduced as an intermediary component between the key cap assembly and the dome switch, preventing direct transmission of weight-induced pressure to the dome switch while allowing the elastic element to maintain its restoring force function
2Reliability
If the key cap, magnetic element and elastic element are designed to be lightweight, then accidental activation is reduced, but the restoring force may be insufficient
Solution Approach 1:
The spiral structure parameters (coil diameter, wire thickness, coil spacing) are optimized to achieve the desired balance between weight and restoring force, allowing the elastic element to be lightweight while maintaining sufficient elastic recovery capability
Solution Approach 2:
The elastic element is made from composite materials or optimized polymer compositions that provide high elastic modulus-to-weight ratio, achieving maximum restoring force with minimum weight
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 design effectively reduces the likelihood of accidental dome switch activation by distributing the weight of the key cap and magnetic element through the adjustable spiral structure of the elastic element and preventing foreign interference, enhancing the accuracy of signal transmission.
Implementation Method 1
The elastic element D is made of a soft material with excellent elasticity. When the key cap B moves, the elastic element D is deformed to generate a restoring force to pull the key cap B back to the original position.
Implementation Method 2
The magnetic element C is disposed inside the key cap B. The displacement detection means F can be electrically connected to an external electrical device. A plurality of Hall sensors are configured in the displacement detection means F, for detecting the movement of the key cap B.
Data Source
AI summary
A low-profile multi-directional key switch structure is disclosed, which includes a magnetic element, a key cap for receiving at least a portion of the magnetic element therein, an elastic element centered near the key cap, and a protection pad disposed between the extension portion of the key cap and the elastic element. The key cap has an extension portion protruding outwardly. The elastic element includes a central region and a spiral structure connected with the central region. The spiral structure is extended from the central region outwardly, and the elastic element is centered near the key cap by the central region for limiting a movement of the key cap and the magnetic element to an original location of the elastic element. The protection pad covers a most portion of the spiral structure of the elastic element, and a receiving opening is disposed in a center of the protection pad for passing the magnetic element through.