Music – Accessories – Tuning devices
Reexamination Certificate
2003-04-21
2004-04-27
Lockett, Kimberly (Department: 2837)
Music
Accessories
Tuning devices
C084S458000
Reexamination Certificate
active
06727416
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
Applicant's invention relates to a device for adjusting the hammers in upright pianos and a method for using same. More particularly, it relates to a device and method to adjust the rake, hammer bore length, and shank length.
Background Information
Conventional upright pianos, including such variations as spinets, consoles, studios, and grand uprights, have the piano action located vertically inside the piano case and a few inches away from the piano strings. The strings are installed in such a way that, along the bridging, the strings rise and slope to the rear and wrap on the piano harp hitch pin which is known as the rear string bearing. Likewise, the slope in front of the bridge, called the front bearing, and the string terminates at the agraffs. The piano hammer is attached to hammer shank which connects into a hammer butt which is attached to the action by a flange. When a key is pressed, the hammer rotates along an arc until it contacts a piano string.
Ideally, the hammer should contact the string directly on its crown and at a 90% angle, or perpendicular to the string. However, because the string is not exactly vertical and the hammer is traveling along an arc, adjusting the hammer to make the ideal hit is a difficult procedure. Additionally, the hammer should strike the string one-eighth of an inch from the center of the front bearing, making the length of the hammer shank an important measurement as well. Further increasing the difficulty, each hammer in the piano has a different shank length and travels along a different arc necessitating that each hammer be individually measured and adjusted.
If the hammer does not contact the string at 90%, one-eighth of an inch below the front bearing, and on the hammer crown, the hammer strike will not produce the piano's best possible sound. If the hammer shoulders contact the string or if hammer contacts at a different angle or at a different point, the piano will not produce a brilliant and clean sound. However, if the hammer is adjusted correctly, the piano will produce the best possible sound, making sustained music that has clarity, power, and projection.
The parameters of string deflection and piano mechanism distance to the string, coupled with the fact that the hammer center crown must strike the string at a pre-determined point below the agraff makes the process of hammer installation and adjustment a challenging project. The piano technician must find the correct bore distance, rake, and shank length to achieve a 90% hammer strike at a pre-determined point along the string. Unfortunately, the correct tolerances vary from piano to piano, even within the same brands.
Generally, piano technicians will remove the old hammer with the shank and butt and try to duplicate the existing hammer dimensions. Unfortunately, it is difficult to replicate an old hammer, in part due to wear and replication problems, and it also assumes that the old hammer was correctly adjustment, which may not be correct.
Thus, there is a need for a device and method for correctly measuring the bore distance, rake, and shank length of pianos.
SUMMARY OF THE INVENTION
The present invention measures the bore distance, rake, and shank length of an upright piano hammer in order to optimize the strike point and position of the piano hammer. The method of the present invention involves the usage of the device in order to correctly measure and install piano hammers in a piano in order to optimize the strike-pointed position of the hammer and thereby obtain the piano's optimal sound quality.
The present invention provides a novel apparatus that will accurately measure the three most important elements of piano hammer installation: (1) bore length, (2) rake, and (3) piano shank length.
The present invention further provides:
a. A single device that is compatible with many and various upright pianos;
b. Adjustments that can be made inside a specific piano to account for that individual piano's characteristics; and
c. A method to precisely measure those angles and distances unique to the subject piano so that piano hammers can be correctly and optimally installed.
In order to solve the difficulties presented in attempting to obtain these features, an apparatus has been developed which is attached to the existing hammer shank and simulates a piano hammer. However, the present invention's dimensions and angles are adjustable so that, as it is moved into strike position, it can be adjusted to meet the optimal strike point of the piano string. The multiple adjustments allow the piano technician to measure the characteristics needed for optimal adjustment of the installed piano hammer.
The method of use of the present invention involves determining the optimal measurements and angles of the hammer to strike the piano string at its optimal strike point.
Specifically, the present invention provides for a device and method to achieve a 90% perpendicular angle strike on the piano string by the piano hammer's center crown at a desired point along the piano string, thus, obtaining the optimal clarity, power, projection, and sustaining quality of sound of that piano.
REFERENCES:
patent: 3696699 (1972-10-01), Tachida
patent: 4686879 (1987-08-01), Ito et al.
patent: 4896577 (1990-01-01), Trivelas et al.
patent: 5565636 (1996-10-01), Sugiyama
patent: 6087574 (2000-07-01), Kitashima et al.
patent: 6509517 (2003-01-01), Wroblewski
Jackson & Walker, LLP
Lockett Kimberly
White Cline H.
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