 |
Description  |
|
|
This invention relates to stringed musical instruments, and more
particularly, to mechanisms for adjusting the spatial relationship between
a string and a fingerboard on a stringed musical instrument.
In recent years the music equipment industry has gone through a revolution
in the construction and use of various instruments and devices. The
amplified electronic music of professional performing groups like "The
Who" and "The Rolling Stones" is as commonly heard as the classic refrains
of Bach and Beethoven. This "new" music often requires that subtle tones
be reproduced and amplified with great clarity. One problem in string
instruments created by this amplification is that heretofore unnoticed
distortions and imperfections will be amplified along with pleasant
sounds, even though it is often not desirable to hear many of these
distortions. Such distortions may arise, for example, where a string of a
guitar vibrates against the fret members of a guitar producing a "buzz"
sound. When amplified, this "buzz" sound can become loud, annoying and
distracting. Instrumentalists may labor for many hours, making delicate,
and often frustrating trial and error adjustments to their equipment so as
to avoid this "buzz". The time lost on this labor can amount to hundreds
of precious work hours.
In common instrument usage, the "nut" of a stringed instrument is an insert
piece of bone, plastic or the like, which fits at the end of the
fingerboard and acts as a support upon which the instrument's strings are
positioned. A series of "V" shaped notches are molded or filed into the
nut so that the strings are maintained in their respective lateral
positions. The V-shaped notches also provide for a two-point contact to
lock-in the string and to minimize buzzing or vibrational noises. Thus, as
the string enters the notch from the peghead, a first contact is made,
while a second contact point is present when the string emerges from the
notch and proceeds toward the frets.
The nut also plays an important role in determining the height of the
string above the fingerboard, commonly referred to as "action". This
parameter is considered of importance to many players of stringed
instruments because of the unique or distinctive playing "feel" and speed
they are able to obtain, depending upon the particular "action"
characteristic of an instrument's structure. Previous designs, however,
allow for little or no adjustment of this "action", thereby limiting the
versatility of a player operating with a particular instrument. In some
cases, the vertical adjustment of a string at either the neck end or
bridged end of the strings can only be accomplished by a similar vertical
adjustment to all of the strings on the instrument. In other cases,
mechanisms have been devised to permit vertical adjustment of each
individual string, but such mechanisms do not provide the certainty and
reliability of either the aforementioned V-shaped notches or the two-point
contact. Such prior art structures are also disadvantageous because they
are complicated in structure and hence expensive to manufacture and use.
Other arrangements have provided that in order to avoid unwanted
"buzzing", a string must fit exactly into a slot so as not to vibrate
against the slot's walls. Still other devices have allowed a string to lie
on a flat surface of an adjusting screw, therefore not being assured of
correct intonation or vibrating length.
It is, therefore, an object of this invention to obviate one or more of the
aforesaid inadequacies.
It is another object of this invention to provide the instrumentalist with
an adjustable nut assembly for individually adjusting the spatial
relationship between each instrument string and fretboard.
It is a further object of this invention to provide a mechanism for
vertical adjustment of each individual string which is simple,
uncomplicated, does not require hand filing of the nut, and is less
expensive to manufacture than existing devices.
Yet another object of this invention is to provide improved string
adjusting means for guitars or the like where the adjustment of the nut
height of one string will not affect the other strings while reliable
contact points for the string are provided.
Still another object of this invention is to provide adjustable inserts for
the "nut" of an instrument which can vary the "action" of a string with
respect to the fretboard.
And it is still a further object of this invention to provide for easily
made owner adjustment of string height to satisfy individual playing
preferences.
Additional objects and advantages of this invention will become apparent
when considered in conjunction with one particular illustrative embodiment
of the invention, wherein a typical adjustable nut includes an underlying
support piece similar in shape to nuts currently in use. The support piece
is provided with a number of holes corresponding to the number of strings
or string pairs of the particular instrument. These holes are tapped or
threaded to accommodate a threaded metal insert, the holes and inserts
being threaded with a very shallow thread pitch so that very fine vertical
adjustments can be made as the insert is rotated in its fitting. The
insert may be turned like a common screw, thereby permitting it to be
raised or lowered with respect to the underlying support mechanism; slots
in the insert's upper surface may be used to effect rotation, although
manual rotation is also envisioned. The inserts are arranged at an acute
angle from the vertical, which angle results in the inserts slanting back
toward the peghead of the instrument; the threads of the inserts and their
accommodating holes permit appropriate adjustment along the angular axis.
The head of each insert is slotted so as to accept and hold a string (for a
four, five of six-string instrument) or string pair (for a paired-string
instrument). In one embodiment of the insert, two slots are cut into the
surface of its head and are positioned perpendicular to each other. Each
slot can accommodate one string, thus being suitable for a six-string
instrument. In another embodiment, two pairs of parallel slots are
provided, each pair perpendicular to the other pair. In the latter case,
six inserts, for example, would thereby be able to accommodate an ordinary
twelve-string instrument. In each instance, as a particular string enters
the slot at the peghead end, it rides in the slot and emerges in contact
with the opposite edge of the insert's slot, thereby providing a definite
point of departure as the string proceeds toward the frets of the
instrument.
As stated above, the aforementioned slots or pairs of slots are cut into
the head surface of the insert at right angles to each other. The function
of such design is to facilitate a quarter-turn, 90.degree. adjustment of
the insert rather than requiring a half-turn, 180.degree. adjustment. The
resultant device enables a very accurate fine tuning of the action, given
the shallow pitch of the threads. Thus, an entire turn of an insert will
result in a minute change in its vertical height. A half or quarter-turn
adjustment will result in a correspondingly finer adjustment.
The slots in the head or upper surface of the insert are generally V-shaped
to provide reliable gripping or holding action for the string. Such a
shape results in more positive sideways positioning for the string and
also resists longitudinal slippage. A more definite vibrational length is
also achieved by the V-shaped slots.
It is, therefore, a feature of an embodiment of this invention that an
appropriate number of threaded holes are spatially located in a nut base
according to the string requirements of a particular instrument.
It is another feature of an embodiment of this invention that these holes
receive inserts with correspondingly shallow threads, such that an entire
revolution of the insert will result in minimal vertical displacement of
the insert.
It is a further feature of an embodiment of this invention that the
threaded inserts are tilted back toward the neck end-piece from the
horizontal plane of the fretboard.
It is still another feature of an embodiment of this invention that the
head surface area of each insert is slotted or notched in a V-shape.
It is also a feature of an alternative embodiment of this invention that
said insert has two parallel slots placed at right angles to a second pair
of parallel slots on the head surface area of an insert to facilitate use
of said insert in paired string instruments.
Additional objects, features and advantages of the present invention will
become apparent when considered in conjunction with a presently preferred,
but nonetheless illustrative, embodiment of the invention as explained in
the following detailed description and as shown in the accompanying
drawings, wherein:
FIG. 1 is a top plan view of a typical six-string guitar with which the
adjustable nut of this invention is adapted to be used;
FIG. 2 is a enlarged fragmentary perspective view showing the device of the
invention as incorporated at the junction of the neck and peghead portion
of a typical six-string guitar;
FIG. 3 is a fragmentary side cross-sectional view showing a string
proceeding from the peghead portion at the right, through the insert and
proceeding across the fretboard, taken along plane 3--3 of FIG. 2 in the
direction of the arrows;
FIG. 4 is an enlarged fragmentary cross-sectional view of one embodiment of
an insert, showing a single V-shaped notch and a string therein, taken
along the line 4--4 of FIG. 3 in the direction of the arrows;
FIG. 5 is an enlarged fragmentary cross-sectional view of an alternative
embodiment of an insert, comparable to the view of FIG. 4, showing two
V-shaped notches in its head surface with two corresponding strings
therein;
FIG. 6 is a fragmentary side cross-sectional view of an alternate
embodiment of an insert according to the invention, showing a flathead
screw-type configuration of an insert, and supporting a string comparable
to the arrangement shown in FIG. 3;
FIG. 7 is a top perspective view of the alternative embodiment of the
insert of FIG. 6 showing two perpendicular notched grooves cut into its
head surface area; and
FIG. 8 is a top plan view of the surface area of the head of another
alternative embodiment of an insert, showing two pairs of parallel
grooves, one pair meeting the other at right angles.
The drawings illustrate the invention in connection with a conventional
six-string guitar, although it will be appreciated that the invention is
applicable to a variety of stringed musical instruments, including banjos,
mandolins, ukuleles, violins and the like. The main components of the
invention, to be described hereinafter, are a nut base, six threaded bores
spaced equidistantly along the upper surface of the nut base, the bores
being angled backward toward the neck end (which carries the string pegs),
six threaded inserts threadedly mated with said bores, and notches cut
into the head surface area of each insert, each notch being "V"-shaped and
in which a string may rest, with selected opposing notches intersecting at
right angles.
The overall invention is illustrated in use in FIG. 1 as it is incorporated
into a typical six-string guitar 10, inwhich strings 22-27 run from the
peghead end 32 of the instrument 10 across the adjustable nut assembly 12
and then proceed down the fretboard 34 to the strumming section 11 of the
instrument. The passage of the strings over frets 28 establishes the
normal fret-string spacing, with the string being depressed by a player's
fingers so as to contact the fretboard 34 between the frets 28. In
addition, the dimension "Z" is thereby established to create the
adjustable "action" to be discussed below. The inserts for nut assembly 12
may be better seen in FIG. 2, where each of six strings 22-27 is supported
by its own respective insert 14-19 mounted in nut base 30. Nut base 30 is
constructed of bone, brass, aluminum, plastic, or comparably rigid
material, and is affixed to the instrument 10 at the ordinary location for
a typical guitar nut, namely at the junction of the fretboard 34 and the
peghead end 32, as may be seen in FIGS. 1 and 2.
Referring to one insert for descriptive purposes, a typical insert 14 is
threadedly mated with a typical bore 36 in nut base 30. String 22 is
supported by insert 14 to a height Z above the fretboard 34, as seen in
FIG. 3. For each of said inserts, a correspondingly threaded bore 36 is
provided. As also shown in FIG. 3, bore 36 is angled toward the neck end
of the instrument at approximately 105.degree. from the horizontal, an
illustrative angle which provides a rearward departure terminal for a
string (such as 22) as it proceeds over the frets 28. This terminal point
is located immediately below edge 39 as illustrated in FIG. 3. When string
22 extends to the left in FIG. 3 from insert 14 and toward the main
portion 11 of guitar 10, its vibrating length will be measured from the
terminal contact point below edge 39 on insert 14 to the opposite terminal
at the bridge end of the instrument where the string is fixed in place on
the body 11. Insert 14 is adjusted within bore 36 in the nut base 30, so
that the height of its upper surface (carrying slots 44 and 46) is
appropriate for the individual player with respect to fretboard 34. In
this manner, dimension Z is adjusted for each string 22-27 whenever
necessary or desired. This allows individualized control of the "action"
(Z) of each string, with each player having the capability of adjusting
the strings to his own preference.
Various configurations of insert 14 may be envisioned. The insert shown in
FIGS. 3-5 is cylindrical and is threaded to be received into bore 36 of
nut base 30. The recommended thread size for said insert and bore is on
the order of 6/40 or 6/56 threads per inch, thus insuring a fine
adjustment of height for each turn or half-turn of the insert. An
alternate embodiment 54 of insert 14 is shown in FIGS. 6-7, which
resembles a flat-head machine screw with a broad round-head 56 placed over
relatively narrow cylindrical shaft 58.
In the version of insert 14 shown in FIGS. 3 and 4, the upper surface 15 is
provided with a V-shaped notch 46 within which typical string 22 rests. An
insert 14 moves vertically within threaded bore 36, string 22 moves up or
down accordingly. As a practical matter, adjustment of insert 14 may
require temporary withdrawal of string 22 from notch 46--once the proper
vertical height is reached, the string can resume its normal position
within the notch.
A similar but modified insert embodiment 14A is shown in FIG. 5. This
element is usable for dual string support, as in the case of a
twelve-string guitar. Thus, there are two corresponding notches 46A and
46B, each carrying a respective string 22A and 22B. (Notches 44A and 44B
are not visible in FIG. 5.) In other respects, the inserts 14 (FIGS. 3-4)
and 14A (FIG. 5) are substantially identical.
The configuration of the top surface area 60 of the head 56 of a modified
insert 54 is shown in FIGS. 6 and 7, where a configuration for a
six-string instrument is shown. It will be seen that notch 66--66' (FIG.
7) bisects and is perpendicular to notch 64--64', both notches
intersecting at center point 68. An alternate insert head configuration 62
is shown in FIG. 8, which would accommodate a pair of strings of a
paired-string instrument (e.g., a twelve-string guitar) where notches
66A--66A' and 66B--66B' are shown parallel to each other and perpendicular
to a second pair of parallel notches 64A--64A' and 64B--64B', the notches
intersecting at points 68A-D. In the embodiments of FIGS. 6-8, the strings
are carried in the designated notches as with inserts 14 and 14A described
above. However, these "headed" embodiments permit somewhat more ready
access for manual tuning of the inserts, and also provide a more definite
departure point for the strings as they proceed over the frets 28. As
shown best in FIG. 7, the departure point for a string in notch 66--66'
can either be at point 67A or 67B, depending on the orientation of insert
54. The threaded embodiments of FIGS. 6-8 also assures that the string
departure point, such as at 67A, 67B, will be directly over the fretboard
end 31 so that the length of the string 22 will correspond with the length
of the fretboard 34.
In use, a typical string 22 will be securely nestled in notch 44 or 46, in
the case of six-string instruments, or in the corresponding notches of a
paired-string embodiment. The six-string embodiment (shown in FIG. 4) has
string 22 nestled in notch 46 of insert 14. It will be seen that the
string 22 rests in the "V" notch 46 a distance "X" from the bottom 42 of
said notch. In the alternate embodiment shown in FIG. 5, two strings 22A
and 22B are each nestled in a corresponding notch 46A and 46B,
respectively, of insert 14A; the insert is threadedly secured in bore 36
of nut base 30.
In typical operation, an instrumentalist would either purchase an
instrument with an adjustable nut in accordance with the invention or
would replace the standard nut on his stringed instrument with the
invention, affixing the nut base 30 to the instrument 10 in a conventional
manner. Thereafter, the invention may function as a standard nut, but with
the added features of easily adjustable action and minimized unwanted
vibration of the strings. When the action of a string is desired to be
adjusted, subsequently, either at the factory or by an individual
instrumentalist, the appropriate string, or string pair, is loosened and
removed from the insert, whereupon adjustment may commence.
In the prior art, even where string adjustments were at all possible, they
would involve cutting or filling the nut down to a new size, obviously a
tedious and irreversible process relying on undesirable trial and error.
Often, the V-notch would have to be reshaped after each adjustment.
Moreover, even hard-filed notches would not avoid the buzzing because of
the "flat" slidable relationship between the string and the notch. With
the present device, an insert 14-19 may be selectively adjusted to any
position, which is entirely variable, while the V-notch 46 also retains
its form. Fine adjustments are effected by the shallow threading of the
insert 14 and bore 36 co-acting with the quarter-turn adjustment
facilitated by the perpendicular placement of the V-notches (FIGS. 5 and
8). Therefore, in actual use, a quarter-turn rotation of an insert will
accomplish only a very minor change in the action of a string, and may be
easily reversed if an incorrect adjustment has been made.
After suitable adjustments have been made, the strings are retightened. As
seen in FIG. 4, string 22 is thus nestled into V-notch 46 such that the
string is supported at the elevation "X" above the bottom 42 of the notch
46. Distance "X" is in part a function of the diameter of the string 22
and of the shape of the notch and is not of critical importance, as long
as the string 22 does not contact and vibrate against the bottom junction
42.
Furthermore, in all embodiments of this invention, the inserts 14-19 (or 54
or 62) are set into nut base 30 at a back angle which may illustratively
be approximately 105.degree. measured from the horizontal plane of the
fretboard 34 toward the neck end 32 of the instrument 10. This canted
position further reduces the likelihood of improper or extraneous string
vibrations.
Unwanted buzzing of strings against the conventional nut may be minimized
by the aforementioned canted design in the invention. Specifically, the
area of vibrational contact of a string with an insert is focussed at the
leading edge of the insert, for example, at leading edge 39 of insert 14
(FIG. 3), or leading edge 59 (FIG. 6) of insert 54. This focussing is
achieved by the backward cant of the inserts. Vibration of the string is
effectively damped by focussing initial string-insert contact at the
forward edge of the insert head. If the insert is not canted in accordance
with this invention, the string may still vibrate against the entire
surface of a flat prior art notch and result in unwanted buzzing. Canting
the inserts so that the string vibrations are focussed and damped at the
leading edge of the insert is a desirable goal and achievement of this
invention.
It is to be understood that the above-described embodiments are merely the
illustrative of the application of the principles of this invention.
Numerous variations may be devised by those skilled in the art without
departing from the spirit or scope of the invention.
* * * * *
|
|
 |
|
 |
Description |
|
