Keyboard Device Curved Hammer Surface for Stable Contact
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Solution Overview
Problem
Conventional keyboard devices for electronic keyboards face challenges in accurately detecting key depression information due to non-uniform compression of the switch body, leading to unstable contact states between movable and fixed contacts, especially when the hammer's pivotal motion is increased to mimic the touch feeling of an acoustic piano.
Innovation Solution
A keyboard device design where the switch body is compressively deformed uniformly by a hammer with a convexly curved pressure-applying surface, ensuring that the pressure-receiving surface conforms to the pressure-applying surface orientation at the end of pivotal motion, maintaining equal compression across movable contacts and preventing displacement or detachment from fixed contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hammer's pivotal motion is increased to mimic the touch feeling of an acoustic piano, then the touch feeling similarity is improved, but the switch body is compressed non-uniformly causing contact instability
Solution Approach 1:
The pressure-applying surface of the hammer is designed with a convexly curved configuration, and the pressure-receiving surface of the switch body is designed with a concavely curved configuration that conforms to the hammer's pressure-applying surface orientation at the end of pivotal motion. This curvature matching ensures uniform compression distribution across the switch body during hammer pivotal motion, preventing non-uniform compression that would cause contact instability.
Solution Approach 2:
The invention changes the geometric parameters of the pressure-applying and pressure-receiving surfaces by introducing specific curvature radii and orientation angles. The pressure-applying surface has a convex curvature with a specific radius, while the pressure-receiving surface has a concave curvature with a matching radius and oriented at a specific angle relative to the substrate, ensuring that the compression force is distributed uniformly across the switch body during hammer motion.
2Ease of operation
If the hammer's pivotal motion is increased to enhance touch feeling, then the acoustic piano-like feel is improved, but the movable contacts may be displaced or detached from fixed contacts
Solution Approach 1:
The convexly curved pressure-applying surface of the hammer and concavely curved pressure-receiving surface of the switch body are designed with matching curvature radii. This curvature matching ensures that during hammer pivotal motion, the compression force is distributed uniformly across the switch body, preventing displacement or detachment of movable contacts from fixed contacts even with larger pivotal motion amplitudes.
Solution Approach 2:
The pressure-receiving surface is designed with a concave curvature that locally adapts to the hammer's pressure-applying surface geometry. This local quality matching ensures that the compression force is concentrated and distributed appropriately at the contact interface, maintaining stable contact between movable and fixed contacts during dynamic hammer motion.
3Reliability
If the switch body is compressed uniformly, then the contact stability is improved, but the hammer's pivotal motion angle is constrained
Solution Approach 1:
The convexly curved pressure-applying surface and concavely curved pressure-receiving surface with matching curvature radii are designed to work together. This curvature matching allows the hammer to achieve uniform compression of the switch body while maintaining a sufficiently large pivotal motion angle, as the curved surfaces guide the compression force distribution throughout the motion range.
Solution Approach 2:
The invention optimizes the curvature radius parameters of the pressure-applying and pressure-receiving surfaces to achieve a balance between uniform compression and adequate pivotal motion angle. By carefully selecting the curvature radii and their matching relationships, the design enables stable contact while allowing the hammer to pivot through the necessary angle for acoustic piano-like touch feeling.
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
This design ensures stable and accurate detection of key depression information even with larger pivotal motion of the hammer, enhancing the touch feeling similarity to an acoustic piano while preventing contact instability.
Implementation Method 1
Each switch body is formed as a hollow member of an elastic material, such as rubber... the switch body is provided with a first movable contact and a second movable contact... as the pressure-receiving surface of the switch body is pressed by the pressure-applying surface of the hammer in accordance with depression of the key, thereby causing compressive deformation of the switch body
Data Source
AI summary
A keyboard device for an electronic keyboard instrument, capable of ensuring stable contact between movable contacts and fixed contacts of a switch body, to accurately detect key depression information. A hammer has a pressure-applying surface formed in a predetermined configuration. A key switch detects key depression information and includes a substrate with fixed contacts, a hollow switch body with a pressure-receiving surface, and movable contacts provided inside the body. Pressing of the pressure-receiving surface by the pressure-applying surface sequentially brings the movable contacts into contact with the fixed contacts, causing switch body compressive deformation. The pressure-receiving surface and pressure-applying surface are complementary in shape, and an orientation of the former conforms to an orientation of the latter when hammer pivotal motion is terminated after the movable contacts are brought into contact with the fixed contacts.