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Description  |
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electronic stringed musical instrument
in which a string vibration detector, called a pickup device, detects
vibrations of strings and produces electrical signals corresponding to the
detected vibrations, and musical sounds to be produced by musical sound
generating means are controlled in response to the produced electrical
signals, and more particularly, to a technology for mounting a string
supporting unit, used to support one end of each of stretched strings, on
a body unit.
2. Description of the Related Art
The following are descriptions of conventional electronic stringed musical
instruments of this type, and U.S. related applications.
Disclosed in pending U.S. patent application Nos. 112,780; 184,099;
256,398; and 252,914 (assigned to the assignee of this application) are
guitar synthesizers or electronic guitars, which use an electromagnetic
type pickup device, a pitch extracting device, and a pitch designating
device. The pickup device magnetically detects vibration of each string
and produces a pickup signal in response to the detected string vibration.
The pitch extracting device extracts a string vibration cycle (i.e.,
string vibration pitch) from the pickup signal. The pitch designating
device is used to designate a pitch corresponding to the extracted string
vibration pitch. On account of the use of the pitch extracting device, the
guitar synthesizers or electronic guitars of this type are called
electronic stringed musical instruments of a pitch-extraction type.
Disclosed in Japanese Utility Model Disclosure No. 63-51395 (assigned to
the assignee of this application) is an electronic stringed musical
instrument which uses an electromagnetic type pickup device, an envelope
detecting device, and a peak measuring device. The pickup device
magnetically detects vibration of each string and produces a pickup signal
in response to the detected string vibration. The peak detecting device
detects an envelope signal from the pickup signal. The peak measuring
device is used to measure the peak of each envelope signal. The peak of
each envelope signal indicates the strength of a string touch, and the
envelope signal is used to control the volume of a musical sound to be
produced by musical sound generating means.
Since the control of the production of the musical sounds is triggered by
the vibrations of the strings, the aforesaid musical instrument is called
an electronic stringed musical instrument of a string-triggered type.
Disclosed in U.S. Pat. No. 4,723,468, moreover, is an electronic stringed
musical instrument which uses an electromagnetic type pickup device and a
fingering position detecting device. The pickup device magnetically
detects vibration of each string. The position detecting device detects a
fingering position for each string on a fingerboard by using an ultrasonic
waves. A pickup signal produced by the pickup device indicates a state of
vibration of each string, and is used to instruct the start and end of
production of musical sounds by musical sound generating means, and to
control the volume of the produced musical sounds. The instrument of this
type is called an electronic stringed musical instrument of an ultrasonic
type, on account of the use of ultrasonic waves.
Disclosed in U.S. Pat. No. 4,765,219, furthermore, is an electronic
stringed musical instrument of a violin type which uses a pickup device
for electromagnetically detecting vibrations of strings and producing
pickup signals in response to the detected string vibrations.
Disclosed in U.S. Pat. No. 4,702,141, moreover, is an electronic stringed
musical instrument of an optical-pickup type which uses a pickup device
for optically detecting string vibrations and producing pickup signals in
response to the detected string vibrations.
Disclosed in U.S. Pat. No. 4,658,690, furthermore, is an electronic
stringed musical instrument of a Hall-device type which uses a pickup
device for detecting string vibrations by means of a combination of a
Hall-device and a magnet and producing pickup signals in response to the
detected string vibrations.
In order to produce specific musical sounds in response to vibrations of
picked strings, in any of the electronic stringed musical instruments of
various these types, it is essential to provide a pickup device for
detecting the string vibrations produced by a plucking operation as
electrical signals and an electric circuit for electrical processing to
produce the musical sounds. In the case of a so-called electric guitar or
an electronic stringed musical instrument of an electric-guitar type, for
example, the electrical signals are directly amplified or processed as
required, to be used as a sound source for the production of the specific
musical sounds. In the cases of the electronic stringed musical
instruments of the aforementioned pitch-extraction type, string-triggered
type, or ultrasonic type, the electrical signals are used to control the
tone or volume of musical sounds produced by separate musical sound
generating means.
In the conventional electronic stringed musical instruments, the pickup
device and a circuit substrate constituting the specific electric circuit
are arranged around a string supporting member for supporting one end of
each string. In this case, the pickup device and the substrate are mounted
independently of the supporting member, on the body of the stringed
musical instrument. According to this conventional arrangement, therefore,
the string supporting member, the pickup device, and the circuit substrate
are mounted on the instrument body naturally in separate processes. Thus,
the assembly work for the instrument body is troublesome. In this
arrangement, moreover, if the pickup device or the circuit substrate, for
example, must be replaced due to some trouble, it occasionally is
impossible to remove only the damaged element from the instrument body. In
most cases, therefore, some other parts on the instrument body must be
also removed therefrom for the replacement.
In the case of the stringed musical instrument of the string-triggered
type, when a pickup signal is delivered from the pickup device, as
mentioned before, a musical sound of any desired tone, selected among
various tones preset in the musical sound generating means, is produced in
response to the attainment of a predetermined level by the pickup signal.
If a string vibration continues over a predetermined period of time after
the production of the specific musical sound, the level of the pickup
signal following the string vibration exceeds the predetermined level over
the predetermined period of time. Thus, an unexpected sound may sometimes
be produced against a player's intention. In order to prevent this, the
string vibration must be suppressed in a short period of time directly
after the string is plucked.
Disclosed in U.S. Pat. No. 3,015,247 is a stringed musical instrument which
is provided with a string vibration damping member for damping string
vibration in a short period of time after string plucking operation. In
this instrument, however, a string supporting unit for supporting strings
is formed independently of the damping member. When the supporting unit is
fixed to the body of the stringed musical instrument, therefore, the
vibration damping member sometimes cannot be properly pressed against the
string. In such a case, the damping member cannot fulfill its string
vibration damping function.
SUMMARY OF THE INVENTION
The present invention has been contrived in consideration of these
circumstances, and has an object to provide an electronic stringed musical
instrument, in which a pickup device and the like can be readily assembled
and mounted on the body of the instrument, and the pickup device and an
electric circuit substrate can be easily replaced in case of trouble.
Another object of the invention is to provide an electronic stringed
musical instrument capable of securely effectively suppressing string
vibration in a short period of time directly after string plucking
operation.
In order to achieve the former object, an electronic stringed musical
instrument according to the present invention is characterized by
comprising a body unit, at least one string stretched over the body unit,
a string supporting unit removably mounted on the body unit to support and
fix at least one end of the string, string vibration detecting means
removably mounted on the string supporting unit to detect vibration of the
string and deliver an electrical signal corresponding to the detected
vibration, and an electronic processing substrate removably mounted on the
string supporting unit and adapted to perform electric processing for
controlling a musical sound to be produced, in response to the electrical
signal detected by the string vibration detecting means.
In order to achieve the latter object, the electronic stringed musical
instrument according to the present invention is further characterized by
comprising a string vibration damping member located near the string
vibration detecting means to damp the vibration of the string.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic exploded perspective view of an electronic stringed
musical instrument according to the present invention;
FIG. 2 is a schematic plan view of a string supporting unit mounted on the
top surface of a body of the electronic stringed musical instrument;
FIG. 3 is a schematic sectional view taken along line III--III in FIG. 2;
FIG. 4 is a schematic sectional view taken along line IV--IV in FIG. 2;
FIG. 5 is a schematic bottom view of the string supporting unit; and
FIG. 6 is a schematic perspective view of an electromagnetic type pickup
attached to the string supporting unit.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An embodiment of the present invention will now be described with reference
to the accompanying drawings.
FIG. 1 is an exploded perspective view schematically showing an electronic
stringed musical instrument according to an embodiment of this invention.
Electronic stringed musical instrument 1 shown in FIG. 1 is in the form of
a guitar. On body unit 5, which is composed of body 2, neck 3, and head 4,
six strings 6a to 6f (partially shown in FIG. 1) are stretched parallel to
one another between body 2 and head 4, in the longitudinal direction of
neck 3. Each string is a nonmagnetic string (nylon, silk-thread, or gut)
on which magnetic coil spring 7 is fitted at a position near the body-side
end portion thereof (see FIG. 3). The prospective body-side end portions
of strings 6a to 6f are supported by string supporting portion 44 of
string supporting unit 8 (which will be described later with reference to
FIGS. 2 to 5), and are fixed by means of string fixing portion 45.
Supporting unit 8 is removably mounted on the center of the rear portion
of the top surface of body 2. The respective head-side end portions of
strings 6a to 6f are fixed individually to tuning pegs 10 of string
tension adjusting mechanism 9 (which will be described later) fixed to the
top surface of head 4.
Arranged on the top surface of body 2 of body unit 5 are power switch 11,
volume controls 12, mute switches 13, pat control switches 14, rhythm
select switches 15, tone select switches 16, etc., as well as string
supporting unit 8. A circuit substrate (not shown), on which an electric
circuit for electronic stringed musical instrument 1, and speaker 17 are
formed, are arranged inside body 2. Fingerboard 18 (mentioned later) is
mounted on the upper surface of neck 3.
Body 2 are constructed by coupling upper and lower halves 19 and 20, which
are made of synthetic resin and are formed independently of each other, by
means of bolts (not shown). Neck 3 is also made of synthetic resin and is
formed independently of body 2. Neck 3 is coupled integrally to body 2 by
means of bolts (not shown) or the like, after proximal end portion 22 of
neck 3 is fitted into groove 21 formed in the center of the front portion
of the upper surface of body 2.
Belt-shaped metallic reinforcing member 23 extends along the upper surface
of neck 3 and the inner surface of upper half 19 of body 2 from head 4
formed integrally on the free end of neck 3 to a portion of the top
surface of body 2 on which string supporting unit 8 is mounted. Head-side
end portion 24 of reinforcing member 23 is coupled integrally, by means of
bolt 26, to metallic base member 25 of string tension adjusting mechanism
9, which is fixed to the top surface of head 4. Body-side end portion 27
of member 23 is connected to supporting unit 8 by means of bolts 77 (see
FIGS. 2 to 4). Metallic reinforcing member 23 is housed in the entrance of
opening 28 in the upper surface of neck 3. A plurality of bosses 29 are
formed integrally on the bottom surface of opening 28 so as to be arranged
at predetermined intervals in the longitudinal direction, and member 23 is
fixed to neck 3 by means of bolts (not shown) which are inserted in bolt
holes 31 of member 23 and are screwed in tapped holes 30 in the upper end
faces of bosses 29. Body-side end portion 27 of member 23 is inserted in
shallow belt-shaped groove 34 formed in the center of the top surface of
body 2, through hole 33 bored in body-side end plate 32 of neck 3. In this
arrangement, the upper surface of reinforcing member 23 is flush with the
top surface of body 2.
Fingerboard 18 is composed of elastic flexible rubber sheet 36 and circuit
substrate 35 which is attached integrally to the lower surface of sheet
36. Substrate retaining projections are formed individually along the both
longitudinal edges of the lower surface of sheet 36. These projections
have their respective grooves 37 and 38 whose cross section is
substantially C-shaped. Circuit substrate 35 are integrated on flexible
sheet 36 by fitting the both longitudinal edges of substrate 35 in grooves
37 and 38 of sheet 36. Also, substrate 35 and sheet 36 are coupled to each
other by means of bolts (not shown) inserted in bolt holes 39 of sheet 36.
Fixed contacts 40 are provided on the upper surface of circuit substrate
35. Fixed contact 40 are arranged on the upper surface under the strings
at each halftone of each string. Frets 41 are arranged on the upper
surface of flexible sheet 36 at positions corresponding to the individual
halftones of strings 6a to 6f. Movable contacts (not shown) are provided
on the lower surface of sheet 36. Movable contacts are arranged on the
lower surface at positions corresponding to fixed contacts 40. Spacers
(not shown) are interposed between the adjacent movable contacts on the
lower surface of sheet so as to form vertical gaps between the movable
contacts and fixed contacts 40 on substrate 35. If the upper surface of
elastic flexible sheet 36 is depressed, the movable contact which
corresponds to the depressed portion of the upper surface contacts its
corresponding fixed contact 40. As a result, a fret switch which
corresponds to the depressed portion is turned on, so that a predetermined
pitch designating signal is delivered to a musical sound generator circuit
(contained in body 2) as a sound source and the pitch of a musical sound
produced by the sound generator circuit is set. Fixed contacts 40 and the
movable contacts are formed on the upper surface of circuit substrate 35
and the lower surface of flexible sheet 36, respectively, by carbon
printing. Frets 41 and the aforesaid spacers (not shown) are formed
integrally on the upper and lower surfaces of the flexible sheet 36,
respectively. Fingerboard 18 constructed in this manner is placed on
support ribs 42 and 43 formed integrally on the both longitudinal edges of
opening 28 in the upper surface of neck 3 so as to be fitted in opening 28
in a state that it is superposed on the upper surface of metallic
reinforcing member 23. Fingerboard 18 is fixed to neck 3 by means of
bonding agent.
String supporting unit 8 is formed of synthetic resin, and is provided on
its upper surface with string supporting portion 44, string fixing portion
45, mounting portion 47 for string vibration damping member (damper) 46,
mounting portion 49 for spring fixing member 48 which is used to fix coil
springs 7 fitted on strings 6a to 6f, and mounting portion 51 for
electromagnetic type pickups 50 as pickup means, as shown in FIGS. 2 to 5.
Mounting portion 53 for circuit substrate 52 is formed on the lower
surface of unit 8.
String supporting portion 44 is formed substantially in the center of the
upper surface of string supporting unit 8, with respect to the
longitudinal direction of strings 6a to 6f. Portion 44 is composed of a
plurality of string supporting projections 55a to 55f which protrude
substantially vertically at positions corresponding to strings 6a to 6f.
Each projection has horizontal string hole 54 through which its
corresponding string is passed. Hole 54 has a diameter large enough to
allow the passage of coil spring 7, and spring 7 fitted on its
corresponding string is passed through each corresponding hole 54.
String fixing portion 45 is situated on the rear end portion of the upper
surface of string supporting unit 8, and is composed of lower half 56
formed integrally on the upper surface of unit 8 and upper half 57
removably connected to lower half 56 by means of bolts (not shown). The
upper surface of lower half 56 is serrated so that its cross section has
vallies as many as strings 6a to 6f. The bottom end of each valley is in
the form of semicircular groove 58 in which each corresponding string can
be fitted without being damaged. The lower surface of upper half 57, which
contacts the upper surface to lower half 56, is also serrated so that its
cross section has vallies as many as strings 6a to 6f. As in the case of
the upper surface of lower half 56, the bottom end of each valley is in
the form of semicircular groove 59 in which each corresponding string can
be fitted without being damaged. In string fixing portion 45 constructed
in this manner, the body-side end portions of strings 6a to 6f are fitted
into their corresponding grooves 58 of lower half 56 after upper half 57
is removed from lower half 56. Then, the two halves 56 and 57 coupled
together by means of bolts so that the respective body-side end portions
of the strings are fixed on string supporting unit 8, as shown in FIG. 3.
String vibration damping member 46 is used to damp the vibration of plucked
strings in a short period of time (several seconds). It is in the form of
a square pillar made of silicone rubber or hard synthetic rubber. Mounting
portion 47 for damping member 46 is arranged in front of string supporting
portion 44 on the upper surface of string supporting unit 8. Portion 47 is
composed of a groove formed in the upper surface of unit 8 so that damping
member 46 can be press-fitted therein.
Spring fixing member 48 is used to fix coil springs 7 fitted on strings 6a
to 6f and supported by string supporting portion 44. Member 48 is formed
of synthetic resin to have a square pillar shape, and is fitted in
groove-shaped mounting portion 49 defined between supporting portion 44
and fixing portion 45 on the upper surface of string supporting unit 8.
Coil springs 7 are pressed at large-diameter portions 61 of the body-side
ends thereof on to the rear end surface of string supporting portion 44 by
supporting portion-side end face 60 of spring fixing member 48 titled in
mounting portion 49, so that coil spring 7 are fixed on their
corresponding strings with respect to the longitudinal direction thereof.
Before the strings are passed through their corresponding coil springs 7,
the springs are passed individually through string holes 54 of string
supporting portion 44 from the rear end side thereof. Thereafter, spring
fixing member 48 is fitted into mounting portion 49. Formed in the upper
surface of string fixing member 48 are deep grooves 62 which are cut to
the depth of the center holes at positions corresponding to the center
holes of springs 7. Strings 6a to 6f are inserted into their corresponding
springs 7 from the side of string fixing portion 45 toward head 4. As the
strings are fitted in their corresponding deep grooves 62 of fixing member
48 between springs 7 and fixing portion 45, member 48 is fixedly pressed
against groove-shaped mounting portion 49 by the strings.
As shown in FIG. 6, each electromagnetic type pickup 50 includes holder 64
having a plurality of output terminals 63, core 65 mounted on the upper
surface of holder 64, and coil bobbin 67 fitted on core 65 and wound with
coil 66. When coil springs 7 fitted on strings 6a to 6f change magnetic
flux produced in electromagnets (each including core 65, coil 66, and
bobbin 67) of their corresponding electromagnetic type pickups 50 by
string vibration attributable to plucking operation, induced electric
potential is produced. The induced electric potential is detected as an
electrical signal responsive to the string vibration. Mounting portion 51
for pickups 50 is composed of a plurality of stepped through holes 68
which are arranged in front of mounting portion 47 for string vibration
damping member 46 on the upper surface of string supporting unit 8, so as
to correspond to strings 6a to 6f. Pickups 50 are fitted into their
corresponding through holes 68 from the lower openings thereof. In this
case, each electromagnet (including elements 65, 66 and 67) is fitted into
small-diameter portion 69 of its corresponding hole 68 on the upper side
thereof, while each holder 64 is fitted into large-diameter portion 70 on
the lower side. Since electromagnetic type pickups 50 are mounted on
circuit substrate 52 (described in detail later), they are automatically
set in their corresponding through holes 68 when substrate 52 is fixed to
mounting portion 53 on the lower surface of string supporting unit 8.
Mounted on circuit substrate 52 are specific electronic parts 71, circuits
connected to electromagnetic type pickups 50, etc. Parts 71 serve to
process electrical signals detected by pickups 50 and deliver the
processed signals to the musical sound generator circuit as the sound
source (contained in body 2). Substrate 52 is fitted in hollow mounting
portion 53 on the lower surface of string supporting unit 8, and is fixed
to the lower surface by means of bolts (not shown).
String supporting unit 8 constructed in this manner is fitted in hollow 72
in the top surface of body 2, and is removably mounted on body 2 by means
of a plurality of bolts 73. A supporting unit mounting region of the top
surface of body 2, in which hollow 72 is formed, is reinforced by means of
metal plate 74, which is fixed to the inner surface of the upper wall of
upper half 19 of body 2 by means of bolts so as to correspond to the
mounting region. As shown in FIG. 3, the front end portion of plate 74 and
body-side end portion 27 of metallic reinforcing member 23, which projects
from the neck side into groove 34 in the top surface of body 2, face each
other with the upper wall of body 2 or upper half 19 being interposed
their between. These two end portions are fixed to each other by means of
a plurality of bolts 77 penetrating the upper wall of body 2.
A sensor cover (not shown) is removably mounted on string supporting unit 8
so as to protect electromagnetic type pickups 50 and the like, which are
exposed on the upper surface of unit 8. String vibration damping member
(damper) 86 is mounted on the upper surface of body-side end plate 32 at
proximal end portion 22 of neck 3 so as to project upward from the top
surface of body 2.
String tension adjusting mechanism 9 on head 4 includes base member 25, a
plurality of pegs 10 arranged on member 25 so as to correspond to strings
6a to 6f and be slidable in the longitudinal direction of the strings, and
operating members 78 attached to pegs 10 and used to slide the pegs. A
plurality of guide grooves (dovetail grooves) 79 are formed on the upper
surface of base member 25 so as to correspond to strings 6a to 6f and
extend in the longitudinal direction of the strings. Nut 80, which is
formed integrally on the lower portion of its corresponding peg 10, is
slidably fitted in each guide groove 79. Screw rod (male screw) 81 of a
predetermined length is fixed to each nut 80. Rod 81 extends in each
corresponding guide groove 79 toward free end face 82 of base member 25 in
the longitudinal direction of each string. Cylindrical operating member
(bar nut) 78 is threadedly engaged with the free end portion of each screw
rod 81 which projects from groove 79. Operating member 78 has an internal
thread at one end to mate with rod 81, and a hexagonal hole at the other
end to be adapted to engage a tool (hex wrench) for rotating the operating
member 78.
Since one end of each operating member 78 abuts against free end face 82 of
base member 25, if member 78 is turned by means of the hex wrench, each
peg 10, along with its corresponding screw rod 81, slides in guide groove
79 in the longitudinal direction of the string. As pegs 10 are thus slid
relatively to base member 25, strings 6a to 6f, whose head-side end
portions are fixed to pegs 10, are adjusted in tension. This tension
adjustment can be achieved without removing cover 83 from string tension
adjusting mechanism 9. Cover 83, which is removably mounted on head 4, has
guide grooves 84 on its upper surface. Pegs 10 are inserted in grooves 84
for sliding motion. Holes 85 for operating members 78 are bored through
the front end face of cover 83.
In electronic stringed musical instrument 1 of the present embodiment
constructed in this manner, electromagnetic type pickups 50 and circuit
substrate 52 are attached to string supporting unit 8 which is removably
mounted on body 2. Therefore, pickups 50 and substrate 52 can be set in a
predetermined position in instrument 1 by previously attaching them to
specific mounting portions 51 and 53 in supporting unit 8, and then
mounting unit 8 on a predetermined portion of the top face of body 2 by
means of bolts 73.
If electromagnetic type pickups 50 and circuit substrate 52 are out of
order, they can be easily replaced by removing only string supporting unit
8, among other elements on body 2, from the body.
In the embodiment described above, the present invention is applied to an
electronic stringed musical instrument of a string-triggered type. The
invention is not limited to this embodiment, however, and may be also
applied to electronic stringed musical instruments of a pitch-extraction
type, ultrasonic, etc.
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