Keyboard Device Hammer Bounce Suppression and Key Load Reduction
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Solution Overview
Problem
Conventional keyboard devices for electronic keyboards experience issues with hammer bouncing upon return, increased key load during soft depression, and variation in key gaps due to thermal expansion, affecting playability and keyboard alignment.
Innovation Solution
The keyboard device incorporates a hammer bounce-suppressing member made of urethane foam and a key contact portion with a constant distance between the contact point and the hammer fulcrum, along with a keyframe front design featuring connecting engagement protrusions and recesses for stable bonding, to address these issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the hammer is made to pivot upward in accordance with key depression, then the hammer can strike the keys to produce sound, but the hammer bounces when returning to its original position, causing the key to slowly return and reducing playability
Solution Approach 1:
A hammer bounce-suppressing member is provided on the key at a position forward of the first contact portion. This member suppresses hammer bounce by being brought into contact with the hammer when the hammer returns from the pivotally-moved position to the initial position, cushioning the return motion before the hammer fully returns and the key can slowly return to its original position.
2Force
If the hammer contact point is positioned to achieve proper striking, then the hammer can effectively strike the key, but the distance between the contact point and hammer fulcrum increases during pivotal motion, increasing key load during soft depression
Solution Approach 1:
The hammer is designed with a specific contact geometry where the key contact portion has a curved surface that maintains a substantially constant distance from the hammer fulcrum during pivotal motion. This local geometric property ensures that while the hammer can strike the key effectively, the key load during soft depression is reduced because the distance between the contact point and hammer fulcrum remains constant.
3Ease of manufacture
If the keyframe front is made from molded articles connected together, then the keyboard can be manufactured efficiently, but thermal expansion causes variation in key gaps, affecting keyboard alignment
Solution Approach 1:
The keyframe front is designed with expansion compensation features that account for thermal expansion of the molded articles. By incorporating design elements that allow for controlled expansion and contraction, the keyboard maintains consistent key gaps despite temperature changes, thus preserving keyboard alignment while retaining manufacturing efficiency.
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 suppresses hammer bouncing, reduces key load during soft depression, and maintains consistent key gaps, enhancing playability and long-term stability of the keyboard.
Implementation Method 1
a hammer bounce-suppressing member provided on one of the upper surface of the key and a lower surface of the hammer at a predetermined position forward of the first contact portion and configured to suppress bouncing of the hammer by being brought into contact with the other of the upper surface of the key and the lower surface of the hammer when the hammer returns from the pivotally-moved position to the initial position
Implementation Method 2
a keyframe front design featuring connecting engagement protrusions and recesses for stable bonding, to address these issues
Data Source
AI summary
A keyboard device for an electronic keyboard instrument, capable of suppressing bouncing of a hammer returning to its original position. A key extends in a front-rear direction swingably about a balance rail pin. The hammer is formed vertically pivotally movable between initial and pivotally-moved positions about a hammer fulcrum provided near a rear end of the key and is placed on the key via a key contact portion in contact with a rear end of upper surface of the key from above, for pivotal motion by swinging of the key. A hammer cushion is provided on upper surface of the key at a predetermined location forward of the key contact portion to suppress bouncing of the hammer by contact with a cushion contact portion of the hammer returning from the pivotally-moved position to the initial position by releasing the key depression.