Keyboard Shutter Cutout for Optical Sensor Timing
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Solution Overview
Problem
Conventional sound control apparatuses for keyboard-based musical instruments suffer from erroneous sound generation due to shutter contact with the back check, leading to hammer rebound and impaired touch feeling, and require labor-intensive assembly.
Innovation Solution
A sound control apparatus featuring a plate-shaped shutter integrated with the hammer, with a cutout on one edge to prevent contact with the back check, and optical sensors for accurate sound generation and stop timing setting, eliminating the need for a shutter window and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the shutter is attached to the catcher without a cutout, then the assembly is simpler, but the shutter contacts the back check causing hammer rebound and erroneous sound generation
Solution Approach 1:
The patent extracts the problematic portion of the shutter by forming a cutout (removing material) from the shutter body. This cutout prevents the shutter from contacting the back check during hammer return motion, eliminating the source of rebound and erroneous sound generation while maintaining the rest of the shutter structure for light blocking function
2Ease of operation
If the shutter is attached to the catcher, then the shutter can control light paths, but the shutter contacts the back check causing vibrations that impair touch feeling
Solution Approach 1:
The cutout is extracted from the shutter to eliminate the contact point with the back check. This removes the source of vibrations that would otherwise be transmitted to the key and degrade the player's touch feeling, while the shutter retains its ability to control light paths for sensor activation
3Reliability
If the shutter window is designed with offset halves, then the light path control works, but the assembly requires much labor and time
Solution Approach 1:
The complex shutter window structure with offset halves is replaced by a simpler shutter design incorporating a cutout. This extraction of the problematic window structure eliminates the need for precise offset positioning and complex assembly procedures, significantly improving manufacturing efficiency while maintaining light path control functionality
Solution Approach 2:
Instead of creating a complex window structure to control light paths, the patent inverts the approach by using a solid shutter with a cutout. This reversal of the design concept simplifies the structure and assembly while achieving the same light path control objective through the cutout geometry
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
Prevents erroneous sound generation and maintains a satisfactory touch feeling by preventing shutter contact with the back check, allowing for precise sound timing settings and reducing assembly complexity.
Implementation Method 1
light from the light emitter of the first sensor 65 is intercepted by the shutter 64, while light from the light emitter of the second sensor 66 reaches the light receiver through the lower half 67b of the shutter window 67
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A sound control apparatus for a keyboard-based musical instrument for avoiding a touch of a shutter (6) to a back check (17), thereby appropriately setting a sound generation timing and maintaining a satisfactory touch feeling. The sound control apparatus comprises a shutter (6) integrated with a hammer (5) adapted to swing associated with a swinging motion of a key (4), extending along a plane including a path along which said hammer swings, and formed with a cutout in an edge on an opposite side to a direction in which said hammer swings. An optical sensor (7,8) has a light emitter disposed on one side of the swinging path of said shutter for emitting light, and a light receiver disposed on the other side of the swinging path for receiving the light from said light emitter, and generates a detection signal in accordance with a light receiving state of said light receiver. A CPU sets a sound generation timing at which music sound should be generated based on the detection signal of said optical sensor responsive to opening and closing of a light path of the light from said light emitter of said optical sensor (7,8) by said shutter (6), when said hammer (5) swings.