GB2406955A

GB2406955A - Stringed instrument fretting apparatus

Info

Publication number: GB2406955A
Application number: GB0323362A
Authority: GB
Inventors: Colin Arthur Davis
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-10-07
Filing date: 2003-10-07
Publication date: 2005-04-13
Also published as: GB0323362D0

Abstract

Fretting apparatus for a stringed instrument comprising an electronic keypad 6 adapted for attachment to the fingerboard of the instrument having one key for each of a plurality of chords, a central processor (CPU) for selecting fretting operations as required to produce each chord, a plurality of electrically operated solenoid fretting actuators 11 one for each note of the chords, which actuators are arranged to be selectively operated consequent upon depression of a key appertaining to a predetermined chord so as to effect fretting operations as determined by the CPU which are appropriate for that chord.

Description

1 2406955 Stringed instrument fretting apparatus.

This invention relates to fretting apparatus for stringed instruments and more especially but not exclusively it relates to fretting apparatus for guitars.

The term fretting as used herein means holding down one or more strings of a stringed instrument against frets on the fingerboard of the instrument thereby to select notes played when the strings are plucked or otherwise played. Fretting is usually used for chord selection and since it is accomplished with the fingers it requires a considerable degree of skill and dexterity and many hours of practice in order to make rapid chord changes.

In order to simplify the fretting operation so that chord changes may be made without the need for a high level of manual skill and dexterity, apparatus for attachment to the fngerboard is known which comprises a keypad for chord selection with a key for each chord, in which fretting is effected via mechanical linkages when a key is pressed.

Apparatus of this kind, which uses mechanical linkages coupled to the keys, requires a relatively large force to be applied to the keys for chord selection and in view of the mechanical complexity the necessary linkages must be made to quite close tolerances which may make fabrication problematic.

It is an object of this invention to provide fretting apparatus for attachment to a stringed instrument which facilitates chord selection with a light touch and which may be relatively easily fabricated.

According to the present invention fretting apparatus for a stringed instrument comprises an electronic keypad adapted for attachment to the fngerboard of the instrument having one key for each of a plurality of chords, a central processor (CPU) for selecting fretting operations as required to produce each chord, a plurality of electrically operated solenoid fretting actuators one for each note of the chords, which actuators are arranged to be selectively operated consequent upon depression of a key appertaining to a predetermined chord so as to effect fretting operations as determined by the CPU which are appropriate for that chord.

The solenoid actuators may comprise latching actuators having two stable positional states, said actuators being constrained by a signal of one polarity produced when a key is pressed to move to an operational positional state whereat a string of the instrument is fretted, and constrained by a signal of opposite polarity produced when that key is released to move back to its original non-operational positional state.

The latching actuators may each be driven by a pair of drivers which respectively provide drive signals of opposite polarity, one polarity being used to switch an actuator to the operational positional state and the other polarity being used to switch it back to the non- operational positional state, thereby to effect operation in accordance with signals provided by the CPU.

The solenoid actuators may each comprise an actuator rod to one end of which is attached a string fretter which serves to make contact with a string and hold it against a fret when the solenoid actuator with which it is associated is in its operational positional state.

The apparatus may comprises a housing in which the keypad is mounted including spacers by means of which the string fretters are spaced away from the fngerboard so as to permit of solenoid actuator operation for fretting purposes.

The apparatus may comprise fixing means used to attach the housing to the musical instrument.

The fixing means may comprise at least one strap.

The CPU may comprise a microprocessor including a data store for data that serves to specify fretting operations as required to produce each chord, the fretting operations required to produce a predetermined chord being effected in accordance with stored data appertaining to that chord.

The data store may comprise a lookup table in which details of the fretting operations for each chord are contained and a ROM for a program in accordance with which the apparatus is operated.

The electronic keypad may be a membrane keypad.

One embodiment of the invention will now be described by way of example only with reference to the accompanying drawings, which are somewhat schematic and not to scale, wherein corresponding parts of the various figures bear where appropriate the same numerical designations and in which; Figure 1, is a perspective view of a guitar to which fretting apparatus is fitted, Figure 2, is a plan view of a keypad and housing comprising a part of the fretting apparatus shown in Figure 1, Figure 3, is perspective part cutaway view of the keypad and housing shown in Figure 2, Figure 4, is a perspective view of a solenoid actuator for use in the fretting apparatus, Figure 5, is a sectional view of the keypad and housing as shown in Figures 2, and 3, and, Figure 6, is a somewhat schematic block/circuit diagram of the apparatus.

Referring now to Figure 1, a guitar 1, having a flngerboard 2, in which are set metal frets 3, has attached thereto, fretting apparatus 4.

The fretting apparatus 4, is positioned towards that end of the fmgerboard 2, of the guitar 1, which is adjacent to string tension adjusters 5, so as to cover those of the fingerboard frets 4, which are required for nine of the most commonly used chords which in this embodiment are deemed to be C, F. G. D7, C7, G7, A7, Am, and Dm as may be required for tunes played in the key of C. These chords require use of the first three frets only and thirteen different fretting positions are required in different combinations, one combination for each chord.

As shown in Figure 2, the fretting apparatus comprises a nine key membrane keypad 6, which is supported in a housing 7, the nine most commonly used chords being printed on the keys so as to identify them to a user.

As shown in Figure 5, the housing 7, also contains and supports a keypad support panel 8, a printed circuit board 9, and a spacer/support 10, which is positioned between the keypad support panel 8, and the printed circuit board 9. The housing 7, is also adapted to contain and support thirteen latching solenoid actuators 11, as shown also in Figures 3, and 4, one for each fretting position. As shown most clearly in Figure 4, each solenoid 11, comprises an actuator rod 12, and electrical connection conductors 13. As shown partly in Figure 5, the solenoid actuators 11, are arranged in six rows, one row for each guitar string, the solenoid actuators 11, in each row being mutually spaced apart so that they align with frets to be used by the apparatus.

The housing 7, is arranged to be clamped to the guitar by means of a strap 14, and spaced from the fngerboard 2, by means of spacers 15.

The underside 16 of the housing is pierced with holes 17, through which the actuator rods 12, are arranged to project so that each is correctly positioned in its designated fretting position. The ends of the actuator rods 12, which actually make contact with the strings during a fretting operation, are covered with a plastics material chosen to facilitate fretting.

In use of the apparatus, when a key of the keypad 6, is pressed, predetermined solenoid actuators 11, are simultaneously energised thereby to effect a fretting operation as required to play a chord corresponding to the key pressed. In order to facilitate operation, each of the solenoid actuators 11, is electrically driven as will now be described with reference to Figure 6, wherein for simplicity one key only of the keypad 6, is shown and only one of the solenoid actuators 11, is shown which is believed to be sufficient, since all operate in a similar manner.

Referring now to Figure 6, each key of the keypad 6, embodies a switch such as the switch 18, operation of which is sensed by a microprocessor 19, which is mounted on the printed circuit board 9, shown in Figure S. The microprocessor 19, is arranged to be responsive to operation of all of the keys on the keypad 6, and to a lookup table 20, in which fretting instructions are contained for the appropriate chord to be selected when a particular key is pressed. When the switch 18, is operated the microprocessor 19, sends a signal via a line 21, to operate a solenoid driver 22, which causes solenoid actuator 23, to move to an operational positional state whereat a guitar string (not shown) with which it is associated is fretted. Similarly, other solenoid actuators (not shown) are simultaneously selected by the microprocessor 19, in accordance with instructions in the lookup table 20, as required for the chord appertaining to the key associated with the switch 18.

The solenoid actuators 11, are reciprocating latching devices having two stable states which require a drive signal of one polarity to cause them to latch into an operational positional state and a reverse polarity drive signal to return them to their non-operational positional state. Accordingly when the key associated with the switch 18, is released such that the switch 18, goes open circuit, the microprocessor 19, is arranged to sense this and send a signal via a line 24, to a reverse polarity driver 25, which operates to return the solenoid actuator 23, to its non-operational positional state. Similarly, the other solenoid actuators that were simultaneously operated as just before described, are also returned to their non-operational positional states.

It will be appreciated that each of the solenoid actuators 11, is arranged to be operatively associated with its own pair of drivers corresponding to the drivers 22, 25, the drivers being supported on and connected via the printed circuit board 9, on which the microprocessor 19, and a power supply 26, for the apparatus are also mounted, along with the lookup table 20, and a ROM 27, for a software program in accordance with which the microprocessor 19, is arranged to operate.

As will be appreciated by those familiar with the guitar, and as hereinbefore explained, in order to play the chords as shown printed on the keys 6, in Figure 2, the first three frets only are used and only thirteen solenoids are required for the fretting positions needed to play them. Thus if the apparatus is to be restricted to these chords only, this somewhat simplified solenoid arrangement is sufficient.

However, it is contemplated that various modifications may be made to the apparatus described without departing from the scope of the invention and for example the set of chords represented may be arranged to be changed, as by means of a switch, to a different set as appropriate for each of several different musical key signatures.

Moreover, the keys of the keypad may be adapted to include an illuminated display to indicate which chords are represented, the illuminated display being changed appropriately as a set is selected. It is also contemplated that provision may be made for the chords represented to be customised. In order to facilitate provision of these arrangements a solenoid matrix may be provided comprising eighteen solenoids in six rows of three or twenty four solenoids in six rows of four or for that matter any number which will enable the chords required to be fretted. Additionally it is also envisaged that a keypad having more than nine keys may be provided to provide for a larger chord selection.

Claims

CLAIMS.

1. Fretting apparatus for a stringed instrument comprising an electronic keypad adapted for attachment to the flngerboard of the instrument having one key for each of a plurality of chords, a central processor (CPU) for selecting fretting operations as required to produce each chord, a plurality of electrically operated solenoid fretting actuators one for each note of the chords, which actuators are arranged to be selectively operated consequent upon depression of a key appertaining to a predetermined chord so as to effect fretting operations as determined by the CPU which are appropriate for that chord.

2. Fretting apparatus as claimed in Claim 1, wherein the solenoid actuators comprise latching actuators having two stable positional states, said actuators being constrained by a signal of one polarity produced when a key is pressed to move to an operational positional state whereat a string of the instrument is fretted and constrained by a signal of opposite polarity produced when that key is released to move back to its original non-operational positional state.

3. Fretting apparatus as claimed in Claim 2, wherein the latching actuators are each driven by a pair of drivers which respectively provide drive signals of opposite polarity, one polarity being used to switch an actuator to the operational positional state and the other polarity being used to switch it back to the non-operational positional state? thereby to effect operation in accordance with signals provided by the CPU.

4. Fretting apparatus as claimed in Claim 2 or Claim 3, wherein the solenoid actuators each comprise an actuator rod to one end of which is attached a string fretter which serves to make contact with a string and hold it against a fret when the solenoid actuator with which it is associated is in its operational positional state.

5. Fretting apparatus as claimed in Claim 4, wherein the apparatus comprises a housing in which the keypad is mounted including spacers by means of which the string fretters are spaced away from the fingerboard so as to permit of solenoid actuator operation for fretting purposes.

6. Fretting apparatus as claimed in Claim 5, wherein the apparatus comprises fixing means used to attach the housing to the musical instrument.

7. Fretting apparatus as claimed in Claim 6, wherein the fixing means comprises at least one strap.

8. Fretting apparatus as claimed in any preceding claim, wherein the CPU comprises a microprocessor including a data store for data which serves to specify fretting operations as required to produce each chord, the fretting operations required to produce a predetermined chord being effected in accordance with stored data appertaining to that chord.

9. Fretting apparatus as claimed in Claim 8, wherein the data store comprises a lookup table in which details of the fretting operations for each chord are contained and a ROM for a program in accordance with which the apparatus is operated.

10. Fretting apparatus as claimed in any preceding claim, wherein the electronic keypad is a membrane keypad.

11. Fretting apparatus substantially as hereinbefore described with reference to the accompanying drawings.