Music – Instruments – Stringed
Reexamination Certificate
2003-10-30
2004-11-09
Lockett, Kimberly (Department: 2837)
Music
Instruments
Stringed
C084S305000, C084S306000, C084S303000
Reexamination Certificate
active
06815596
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to a peg for a stringed instrument such as a guitar, and more particularly, relates to a peg for a stringed instrument in which the winding shaft rotates due to the tension of the string, and tuning is thereby made easy.
2. Background Art
The peg used in a stringed instrument such as a guitar generally comprises a worm gear provided coaxialy with respect to a knob, and a worm wheel which meshes with the worm gear and is provided coaxialy with respect to a winding shaft. In this type of peg, a large string tension acts on the winding shaft, and the string tension is often changed due to tuning of the string and choking made for a performance. In addition, because the peg must be mounted within a limited space at the head of the guitar, there are limitations with respect to the structure of the peg. Furthermore, since the peg is required to have a decorative appearance, the parts of the peg are often coated by plating or coating. For this reason, it is difficult to maintain the precision of size in the parts of the peg, and because of this situation, there have been problems hitherto with respect to the structure of the peg.
FIG. 7
shows a cross-sectional view of an example of a peg used in an electric guitar, a folk guitar, and the like. In the peg shown in
FIG. 7
, a main body
1
is mounted to a guitar head H, and a winding shaft
3
having a worm wheel
2
fixed to an end thereof is rotatably supported by the main body
1
. A worm gear which meshes with the worm wheel
2
is rotatably supported by the main body
1
, and a knob having the same axis as the worm gear is fixed to the worm gear (neither is shown).
The worm wheel
2
is closely fitted into the winding shaft
3
such that relative rotation with respect to an end portion thereof is prevented, and the worm wheel
2
is secured to the winding shaft
3
with a screw
4
. In addition, a plate portion
1
a
of the main body
1
is disposed between the shoulder
3
a
of the winding shaft
3
and the bottom surface
2
a
of the worm wheel
2
with a gap. In addition, a screw
1
b
is formed on an inner surface of one end portion of the main body
1
, and a securing nut
5
is screwed to the screw
1
b
. The winding shaft
3
is rotatably inserted through the securing nut
5
.
In the peg described above, a leading end portion of the string is anchored at the string winding surface
3
b
of the winding shaft
3
. When the knob is rotated, the string is wound. In the peg shown in
FIG. 7
, because the plate portion
1
a
of the main body
1
is disposed between the shoulder
3
a
of the winding shaft
3
and the bottom surface
2
a
of the worm wheel
2
with a gap there between them, the winding shaft
3
is rotatable in the direction of slackening due to the tension of the string. Accordingly, the surface of the teeth of the worm wheel
2
is always pressed in a set direction with respect to the surface of the teeth of the worm gear due to the string tension. This type of structure is used because in tuning, and the effects described in the following are achieved.
Specifically, when the string is tensioned, the winding gear
3
is rotated due to the surface of the teeth of the rotating worm gear being pressed against the surface of the teeth of the worm wheel. On the other hand, since the surface of the teeth of worm wheel
2
is pressed to the surface of the teeth of the worm gear in a constant direction, when the worm gear rotates in the direction of slackening of the string, the worm gear rotates along with the worm wheel
2
in the same direction. Accordingly, the string is slackened by the exact amount by which the knob is turned in real time, and this has the advantage that tuning is made easy.
Conversely, the conventional peg has a structure in which the plate portion
1
a
is tightened by shoulder
3
a
of the winding shaft
3
and the bottom surface
2
a
of the worm wheel
2
. In this type of peg, since there is a large amount of frictional resistance between the winding shaft
3
and the main body
1
, the winding shaft is not easily rotated by the string tension. Thus, if after the knob is rotated in one direction, and is rotated again in the opposite direction, there is a time lag corresponding to the amount of backlash of the worm gear and the worm wheel
2
generated between the time when the knob is first rotated until the time when the worm wheel
2
rotates. As a result, there is a problem in that tuning is difficult. In addition, after tuning in the direction of slackening of the strings has been completed, the worm gear may gradually rotate during backlash of the worm wheel
2
due to string tension, and the notes may become out of tune during performance. For this reason, at the time of tuning, a method must be used in which, the sound is adjusted while tensioning the string after the string has been sufficiently slackened, and this is the main reason why tuning is so difficult.
However, even in the winding device shown in
FIG. 7
, many kinds of problems have become apparent. That is to say, the gap between the plate portion
1
a
of the main body
1
and the worm wheel
2
and the shoulder
3
a
of the winding shaft
3
is set such that even if the winding shaft
3
becomes inclined due to the string tension, the winding shaft
3
never moves in the axial direction. However, the dimension of the gap may fluctuate with the precision of the processing or the thickness of the plating of the winding shaft
3
and the plate portion
1
a
. As a result, if the dimension of the gap is smaller than a set value, there is a large amount of frictional resistance between the winding shaft
3
and the main body
1
, and thus, the same problems caused by backlash which are described in the foregoing occur.
On the other hand, if the distance of the gap is larger than the set value, a space is generated in the axial direction in which the winding shaft moves. For this reason when the direction of rotation of the worm gear changes, first the worm wheel
2
moves along with the winding shaft
3
in the axial direction, and when the winding shaft
3
reaches the moving end of the worm wheel
2
, the rotation of the worm gear is transmitted to the worm wheel
2
. That is to say, the gear is in the same state as it is when there is backlash. In addition, when the worm wheel
2
moves in the axial direction, the surface of the teeth thereof are abraded by the corners of the surface of the teeth of the worm gear, and as a result, errors in rotation are caused and a gap is formed between the surfaces of the teeth, thus hindering smooth rotation. Also, when the worm wheel
2
is forcibly rotated, the plate portion
1
a
bends, thus rendering the winding shaft unusable.
Furthermore, in the peg shown in
FIG. 7
by providing the gap between the plate portion
1
a
of the main body
1
and the worm wheel
2
and also between the plate portion
1
a
of the main body
1
and the shoulder
3
a
of the winding shaft
3
, the screw
4
must be fixed loosely. As a result, the screw
4
becomes even looser due to vibrations of the string at the time of performance, and due to sympathetic vibration, the screw may fall out. In an effort to eliminate this problem, the screw
4
has been fixed with an adhesive, but when this is done, repair of the peg becomes extremely difficult.
A peg in which a spring washer is disposed between a worm wheel and a plate portion has also been provided. In this type of peg, movement of the winding shaft in the axial direction is controlled and rotation due to string tensioning becomes possible. However, the material for forming the main body is generally made from a diecast product of soft metals such as aluminum or zinc or brass, or the like. As a result, there is a problem in that the spring washer which is caused to rotate along with the worm wheel shaves the main body. Furthermore, the axial direction position of the worm wheel may vary in accordance with the strength with which the screw is tightened, and more particularly,
Armstrong Kratz Quintos Hanson & Brooks, LLP
Gotoh Gut Co., Ltd.
Lockett Kimberly
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