CN102163424A - Guitar playing auxiliary device - Google Patents

Abstract

The invention relates to a guitar playing auxiliary device. The guitar playing auxiliary device is characterized by comprising a chord pressing mechanism, wherein the chord pressing mechanism comprises a plurality of chord pressing assemblies which are of the same structure and are respectively electrically connected with a control circuit board, the chord pressing assemblies are arranged in a transverse and longitudinal separation line way to form a plurality of square net structures, only one chord pressing assembly is arranged at each intersection point of the square net structures, the plurality of chord pressing assemblies and regions at which all the components on the neck of a guitar are located are in one-to-one correspondence in position, the quantity of the chord pressing assemblies in each column is the same with that of the chords, at least three chord pressing assemblies are arranged in each row, each chord pressing assembly at least comprises chord pressing blocks, the outer ends of the chord pressing blocks penetrate through the base plate of a box body to be exposed out of the box body, the distances between every two adjacent chord pressing blocks in each column and the distances between every two adjacent chords are in one-to-one correspondence in position. When the device provided by the invention is arranged on the neck of the guitar, a player can release or press a corresponding chord while the chord pressing block is controlled to act by pressing a playing key with fingers of one hand, and the player can play the guitar or accompany a singer while the chords are simply stirred or wiped with the other hand.

Description

A kind of guitar is played servicing unit

Technical field

The present invention relates to a kind of guitar and play servicing unit.

Background technology

Guitar is a kind of musical instrument of the player's of needs bimanualness.Generally push the diverse location (being called product) of string upper end with left-hand finger, the lower end of playing or sweeping group string simultaneously with the right hand is to play out melody.Usually, left-handed operation has certain fixing fingering, is called the chord gimmick.The player has only these gimmicks of grasp, and can skillfully switch between these gimmicks neatly, just can cooperate the right hand to sweep string and carry out accompanying song.

For the guitar beginner, the operation of grasping the right hand is relatively easy, and GPRS left hand fingering is very difficult.Main cause has: 1, the guitar string is harder, and beginner's finger can't bear the reacting force of string mostly; 2, the neck of guitar has certain width, and certain distance is arranged between product and the product, and for the less people of hand, left-handed operation is more difficult; 3, some people is because of congenital reason or there is not time enough exercise, and left hand does not reach the required flexibility ratio of accompaniment all the time.For above-mentioned reasons, most of people have finally abandoned playing guitar.

For the people who seeks simple musical instrument vocal accompaniment, guitar is considered to best choice usually.But owing to grasp relatively difficulty of guitar left hand fingering, common people need spend one month even the longer time just can simply accompany, and this is unacceptable for a lot of people.

Also occur some guitars at present and played assistor.It is to utilize different structures to finish the conversion of guitar chord that the guitar that has is played assistor, but described structure exists following defective: conversion chord glibly, and the accompaniment chord can not be assist well, thereby the song of complexity can't be formed; The guitar that has is played the automatic conversion that assistor can not be realized the guitar chord, and the guitar beginner problem of conversion chord is not glibly solved.

Summary of the invention

Technical matters to be solved by this invention provides a kind of guitar and plays servicing unit, this device is installed on the neck of guitar, the player is as long as play key with the finger presses of a hand, by the action of control circuit board control pressed string block, can finish respectively and loosen or push corresponding string (promptly replace people's a hand to loosen or push corresponding string), the player stirs or sweeps string simply with the another hand, can carry out guitar and play or accompany.

For solving the problems of the technologies described above, the invention provides a kind of guitar and play servicing unit, it has hollow box body, be arranged on the box body and in order to this device is installed to the mounting structure on the guitar neck, press string mechanism, be arranged on the some keys of playing on the box body, be arranged in the box body and with play the control circuit board that key is electrically connected, press string mechanism to comprise the identical and some pressure string assemblies that be electrically connected with control circuit board respectively of structure, described pressure string assembly is arranged by the linescan method of lateral separation and longitudinal separation, so that form some square node structures, only there is one to press the string assembly on each joint of square node structure, respectively product region on the neck of described some pressure string assemblies and guitar is corresponding one by one on the position respectively, the quantity of the pressure string assembly in each row is identical with the quantity of string, the quantity of the pressure string assembly in each row is at least three, each presses the string assembly to comprise pressed string block at least, the base plate that the outer end of pressed string block passes box body exposes from box body, and the spacing between per two the adjacent pressed string blocks in each row is corresponding one by one on the position respectively with the spacing between per two adjacent strings.

For can concise description for the purpose of the problem, below a kind of guitar of the present invention is played servicing unit all abbreviate this device as.

Described control circuit board is used for the internal control of this device, has stored each in the control circuit board and has played key, plays the mapping relations program of the respective numbers pressed string block action that key is associated with this.Specifically be exactly: pre-defined and set up the mapping relations table of playing key and pressed string block action in the control circuit board, chord commonly used is only played key by one or is simply played key combination and can realize; One or more different mapping relations tables can be stored in the control circuit board simultaneously, and the player selects one of them to get final product before playing; The player can change the mapping relations table as required, and change back mapping relations table is with standing storage, up to changing once more or resetting.

This device is installed to the neck of guitar by mounting structure, guarantee that the spacing between per two the adjacent pressed string blocks in each row is corresponding one by one on the position respectively with the spacing between per two adjacent strings, and leave the gap between pressed string block and the string, make this device and the relative position of neck fix.

The principle of work of this device is: when playing, the player as required, optionally push one and play key or several combination of playing key, control circuit board is according to the mapping relations table of playing the action of key and pressed string block, pressure string assembly to respective numbers sends instruction, press the string assembly to allow corresponding pressed string block move, make the traversing through end of pressed string block realize loosening or pushing corresponding string respectively, realize the chord conversion according to instruction.

In sum, this device is installed on the neck of guitar, the player is as long as play key with the finger presses of a hand, by the action of control circuit board control pressed string block, can realize loosening or push corresponding string (promptly replace people's a hand to loosen or push corresponding string) respectively, the player stirs or sweeps string simply with the another hand, can carry out guitar and play or accompany.

As of the present invention one preferred, described each pressure string assembly also comprises the motor that places in the box body, worm screw, the worm sector that is meshed with worm screw, vertical cantilever, limit switch, motor is installed in the box body and with control circuit board and is electrically connected, motor shaft is connected with worm screw is coaxial, the arc section upside engagement of worm and wheel, the arc section downside of worm gear respectively with the inner of pressed string block, the upper end of cantilever joins, on the worm gear with the arc section of worm gear away from the radially other end and box plate hinged, limit switch be installed in the box body and the position corresponding with cantilever, respectively there is a vertical limiting plate that extends upward and point to worm gear the length direction both sides of limit switch, and the lower end of cantilever places between two limiting plates.

Adopt above-mentioned pressure string assembly, when playing, the player as required, optionally push one and play key or several combination of playing key, control circuit board is according to the mapping relations table of playing the action of key and pressed string block, pressure string assembly to respective numbers sends instruction, press the string assembly to allow corresponding motor rotate by corresponding direction according to instruction, for described each pressure string assembly, rotate up and down around its articulated position by the worm drive worm gear, allow be arranged on also action thereupon of corresponding pressed string block on the worm gear, when the arc section of worm gear arrives its limes superiors position or smallest limit position respectively, make the traversing through end of pressed string block finish respectively to loosen or push corresponding string, realize the chord conversion, make cantilever contact with the limiting plate of respective side respectively simultaneously, trigger limit switch, allow the motor stall.

Another is preferred as of the present invention, described each pressure string assembly also comprises electromagnetic relay, the elastic sheet metal that places in the box body, one end of sheet metal has the arc fold bending section, the pairing center of circle of bending section is near the other end of sheet metal, the coil of electromagnetic relay is electrically connected with control circuit board, sheet metal joins by bending section and electromagnetic relay, and the other end of sheet metal and the inner of pressed string block join, and electromagnetic relay, pressed string block are in the both sides of sheet metal respectively.

Adopt above-mentioned pressure string assembly, when playing, the player as required, optionally push one and play key or several combination of playing key, control circuit board is according to the mapping relations table of playing the action of key and pressed string block, pressure string assembly to respective numbers sends instruction, press the string assembly to allow the coil of corresponding electromagnetic relay get electric or dead electricity according to instruction, for described each pressure string assembly, by coil absorption or relieving sheet metal, allow be arranged on also action thereupon of corresponding pressed string block on the sheet metal other end, make the traversing through end of pressed string block finish respectively to loosen or push corresponding string, realize the chord conversion.

Another is preferred as of the present invention, described each motor of pressing string assembly also to comprise to place in the box body, screw rod, the eccentric nut that is slidingly matched with box body, motor is electrically connected with control circuit board, motor shaft is connected with screw coaxial, one end of screw rod and eccentric nut spins, the other end of eccentric nut and the inner of pressed string block join, and motor, pressed string block are in the both sides of eccentric nut respectively.

Adopt above-mentioned pressure string assembly, when playing, the player as required, optionally push one and play key or several combination of playing key, control circuit board is according to the mapping relations table of playing the action of key and pressed string block, pressure string assembly to respective numbers sends instruction, press the string assembly to allow corresponding motor rotate by corresponding direction according to instruction, for described each pressure string assembly, move along screw axial by the screw drive eccentric nut, allow be arranged on also action thereupon of corresponding pressed string block on the eccentric nut, make the traversing through end of pressed string block finish respectively to loosen or push corresponding string, realize the chord conversion.

As present invention further optimization, the interface that links to each other with computer is arranged on the described control circuit board; Described mounting structure comprises two semicircle collars, and two collars lay respectively at the upper and lower of the base plate of box body, homonymy one end of two collars and the base plate hinged of box body, the homonymy other end of two collars and the base plate clamping of box body.

Adopt described interface, control circuit board is connected with computer by interface, be convenient in control circuit board to store each and play key, play the mapping relations program that respective numbers pressed string block that key is associated moves with this; Adopt above-mentioned mounting structure, make this device be easy to be installed to the neck of guitar, this device and the neck of guitar are fixed.

This device is applicable to the guitar beginner, wish association's guitar vocal accompaniment in the short time the singer, because of congenital or day after tomorrow reason can not effectively compress the player of guitar string etc. flexibly.

Description of drawings

Fig. 1 is the work installation diagram of this device embodiment one;

Fig. 2 is the stereographic map of this device embodiment one;

Fig. 3 surveys exploded perspective view for the axle of this device embodiment one;

Fig. 4 is for pressing the stereographic map of string assembly among this device embodiment one;

Fig. 5 is the B portion enlarged drawing of Fig. 1;

Fig. 6 is the theory diagram of control circuit board among this device embodiment one;

Fig. 6-1 is the circuit diagram of circuit for controlling motor among Fig. 6;

Fig. 6-2 is the circuit diagram of main control circuit among Fig. 6;

Fig. 6-3 is the circuit diagram of usb circuit among Fig. 6;

Fig. 6-4 is the circuit diagram of keyboard input control circuit among Fig. 6;

Fig. 7 is for pressing the stereographic map of string assembly among this device embodiment two;

Fig. 8 is for pressing the stereographic map of string assembly among this device embodiment three.

Embodiment

Further specify the present invention below in conjunction with accompanying drawing and by embodiment.

Embodiment one

Referring to Fig. 1-Fig. 5, this device hashollow box body 1, be arranged on thebox body 1 and in order to the mounting structure on the neck A1 that this device is installed to guitar A, press string mechanism, be arranged on thebox body 1 sevenplay key 4, be arranged in thebox body 1 and with play thecontrol circuit board 5 thatkey 4 is electrically connected, the interface (not shown described interface among Fig. 4) that links to each other with computer is arranged on the control circuit board 5.Box body 1 comprisesloam cake 11 andbase plate 12.

For can concise description for the purpose of the problem, only show two among Fig. 1, Fig. 2, Fig. 5 and playkey 4, Fig. 4 only show described twoplay key 4 pass hole (not shown two piece numbers that pass the hole among Fig. 4).Playkey 4 and be arranged on the side ofloam cake 11.

Press string mechanism to comprise 24pressure string assemblies 3 that structure is identical and be electrically connected withcontrol circuit board 5 respectively, describedpressure string assembly 3 is arranged by the linescan method of lateral separation and longitudinal separation simultaneously, so that form some square node structures, only there is one to pressstring assembly 3 on each joint of square node structure, the quantity of thepressure string assembly 3 in each row is identical with the quantity of string (to be six, the piece number of not shown string among Fig. 1, Fig. 5), the quantity of thepressure string assembly 3 in each row is four.

Each is pressedstring assembly 3 to comprise pressedstring block 31 and placesmotor 32 in thebox body 1,worm screw 33, theworm sector 34 that is meshed withworm screw 33,vertical cantilever 35,limit switch 36,motor 32 is installed in thebox body 1 and withcontrol circuit board 5 and is electrically connected, motor shaft and 33 coaxial connections of worm screw,worm screw 33 meshes with the arc section upside ofworm gear 34, the arc section downside ofworm gear 34 respectively with the inner of pressedstring block 31, the upper end ofcantilever 35 joins, on theworm gear 34 with the arc section ofworm gear 34 away from the radiallyother end 37 hinged with thebase plate 12 ofbox body 1,limit switch 36 be installed in thebox body 1 and the position corresponding withcantilever 35, respectively there is a verticallimiting plate 361 that extends upward and point toworm gear 34 the length direction both sides oflimit switch 36, and the lower end ofcantilever 35 places between twolimiting plates 361.

Thebase plate 12 that the outer end of pressedstring block 31passes box body 1 exposes frombox body 1, and the spacing between per two the adjacent pressedstring blocks 31 in each row is corresponding one by one on the position respectively with the spacing between per two adjacent strings.

Mounting structure comprises that 2, twocollars 2 of two semicircle collars lay respectively at the upper and lower of thebase plate 12 ofbox body 1, and homonymy one end of twocollars 2 and thebase plate 12 ofbox body 1 are hinged,base plate 12 clampings of the homonymy other end of twocollars 2 and box body 1.This device is installed to the neck A1 of guitar A by mounting structure, guarantee that the spacing between per longitudinally two adjacent pressedstring blocks 31 is corresponding one by one on the position respectively with the spacing between per two adjacent strings in each row, and leave the gap between pressedstring block 31 and the string, make this device and the relative position of neck A1 fix.

Referring to Fig. 6, control circuit board is used for the internal control of this device, and is made up of keyboard input control circuit, usb circuit, circuit for controlling motor and main control circuit.

The keyboard input control circuit is used for the signal of the function key of playingkey 4 and other potential designs is inputed to main control circuit.

Usb circuit is used for realizing being connected of this device and computer, is used incontrol circuit board 5 pre-defined and set up the mapping relations table of playingkey 4 and pressedstring block 31 actions.The player can change the mapping relations table as required, and change back mapping relations table is with standing storage, up to changing once more or resetting.

Circuit for controlling motor is used for carrying out the steering order (rotating with stop) of themotor 32 of main control circuit and sends the position signalling ofmotor 32 to main control circuit.

Having stored each in the main control circuit playskey 4, plays the mapping relations program of respective numbers pressedstring block 31 actions thatkey 4 is associated with this.One or more different mapping relations tables can be stored in thecontrol circuit board 5 simultaneously, and the player selects one of them to get final product before playing.

Arbitraryly play the combination that key 4(chord commonly used only playskey 4 by or simply playkey 4 and can realize as long as press),control circuit board 5 is under the control of mapping relations program, to sending control signal with thiscorresponding motor 32 of playingkey 4 and have in thepressure string assembly 3 of mapping relations, controlcorresponding motor 32 is rotated, thereby makes corresponding pressedstring block 31 push, loosen string.

Referring to Fig. 6-1, circuit for controlling motor is by motor control chip, data selector, code translator, form with door, phase inverter etc.Because themotor 32 that will control is more, drawing breadth is limited, so only announced in arbitrary row the circuit for controlling motor of fourmotors 32 in four horizontalpressure string assemblies 3 among Fig. 6-1.Circuit for controlling motor is by motor control chip IC1-IC4, data selector U1, code translator U2, with a door U3A, form with door U3B, a phase inverter U4A, motor control chip IC1-IC4 adopts motor control chip L9110, data selector U1 adopts 74HC153, code translator U2 adopts 74HC155, with door U3A, adopt a 74LS08 with door U3B, phase inverter U4A adopts 74LS14.Motor control chip IC1-IC4 is responsible for controlling the rotating of fourmotors 32 and stopping.Gate circuit is responsible for makingmotor 32 stalls whenmotor 32 puts in place.Because four 32 same times of motor have only a rotation, so adopt data selector 74HC153 and code translator 74HC155.Data selector 74HC153 is responsible for according to choice of location and input control signal whenfront motor 32, and code translator 74HC155 is responsible for outputing it to according to the control signal of main control circuit the control end of themotor 32 of appointment.Circuit for controlling motor also can adopt the H bridge circuit.

Referring to Fig. 6-2, main control circuit is made up of single-chip microcomputer U17, oscillatory circuit, reset circuit.Oscillatory circuit is made of crystal oscillator Y1, capacitor C 22, capacitor C 26, and reset circuit is made ofresistance R 1, capacitor C 27 and switch S 7, and single-chip microcomputer U17 adopts the atmega16 of AVR.Main control circuit is the core ofcontrol circuit board 5, the pre-defined mapping relations table of playingkey 4 and pressedstring block 31 actions, and having stored each in the main control circuit playskey 4 and plays the mapping relations program that pressedstring block 31 thatkey 4 is associated moves with this, like this, by this device of mapping relations program controlled system.

Referring to Fig. 6-3, usb circuit uses USB bridging chip CH341T chip, is connected with single-chip microcomputer U17 by serial ports, realizes the input of PC end data.Be connected with computer by interface, can manually set up or change the mapping relations table of playingkey 4 and pressedstring block 31 actions easily.

Referring to Fig. 6-4, the keyboard input control circuit is made up of 3*4 matrix keyboard S1-S13, and wherein: seven keys are for playingkey 4, and all the other are function key, and each ranks circuit is connected with the IO mouth of single-chip microcomputer U17 in the main control circuit.

The principle of work of this device is: when playing, the player as required, optionally push one and playkey 4 or several combination of playingkey 4,control circuit board 5 is according to the mapping relations table of playingkey 4 and pressedstring block 31 actions,pressure string assembly 3 to respective numbers sends instruction,press string assembly 3 to allowcorresponding motor 32 rotate by corresponding direction according to instruction, for described eachpressure string assembly 3, drivingworm gear 34 byworm screw 33 rotates up and down around its articulated position, allow the corresponding pressedstring block 31 that is arranged on theworm gear 34 also move thereupon, when the arc section ofworm gear 34 arrives its limes superiors position or smallest limit position respectively, make the traversing through end of pressedstring block 31 finish respectively to loosen or push corresponding string, realize the chord conversion, makecantilever 35 contact with thelimiting plate 361 of respective side respectively simultaneously,trigger limit switch 36, allowmotor 32 stalls.

In sum, this device is installed on the neck A1 of guitar A, the player is as long as playkey 4 with the finger presses of a hand, by 31 actions ofcontrol circuit board 5 control pressed string blocks, can realize loosening or push corresponding string (promptly replace people's a hand to loosen or push corresponding string) respectively, the player stirs or sweeps string simply with the another hand, can carry out guitar and play or accompany.

This device all is suitable for for the guitar of left hand control chord and the guitar of right hand control chord.

Embodiment two

Need to prove, in this device except that control circuit board, each presses string assembly, all the other concrete structures are identical with embodiment one, so here all the other concrete structures of this device are repeated no more.Because control circuit board is the prior art part, and very little, so here the concrete structure of the control circuit board of this device is also repeated no more with the difference of control circuit board among the embodiment one.

Referring to Fig. 7, described each pressure string assembly comprises pressedstring block 1 and places box body interiorelectromagnetic relay 2,elastic sheet metal 3, one end ofsheet metal 3 has arcfold bending section 31, thebending section 31 pairing centers of circle are near theother end 32 ofsheet metal 3, thecoil 21 ofelectromagnetic relay 2 is electrically connected with control circuit board,sheet metal 3 joins bybending section 31 andelectromagnetic relay 2, theother end 32 ofsheet metal 3 joins with the inner of pressedstring block 1, andelectromagnetic relay 2, pressedstring block 1 are in the both sides ofsheet metal 3 respectively.

Adopt above-mentioned pressure string assembly, when playing, the player as required, optionally play key or several combination of playing key by the next one, control circuit board is according to the mapping relations table of playing key and pressedstring block 1 action, pressure string assembly to respective numbers sends instruction, press the string assembly to allow thecoil 21 of correspondingelectromagnetic relay 2 get electric or dead electricity according to instruction, for described each pressure string assembly, bycoil 21 absorption or relievingsheet metal 3, allow also action thereupon of corresponding pressedstring block 1 on theother end 32 that is arranged onsheet metal 3, make the traversing through end of pressedstring block 1 finish respectively to loosen or push corresponding string, realize the chord conversion.

Embodiment three

Need to prove, in this device except that control circuit board, each presses string assembly, all the other concrete structures are identical with embodiment one, so here all the other concrete structures of this device are repeated no more.Because control circuit board is the prior art part, and very little, so here the concrete structure of the control circuit board of this device is also repeated no more with the difference of control circuit board among the embodiment one.

Referring to Fig. 7, described eachmotor 1 of pressing string assembly also to comprise to place in the box body, screwrod 2, theeccentric nut 3 that is slidingly matched with box body,motor 1 is electrically connected with control circuit board, motor shaft is connected with screw coaxial,screw rod 2 spins with an end ofeccentric nut 3, the inner of the other end ofeccentric nut 3 and pressedstring block 4 joins, andmotor 1, pressedstring block 4 are in the both sides ofeccentric nut 3 respectively.

Need to prove, for each presses the string assembly, the needed sliding matching structure that is slidingly matched betweeneccentric nut 3 and the box body is: two symmetrical guide rails are arranged on theeccentric nut 3, and there are corresponding two guide-track grooves the inboard of box body, and two guide rails place two guide-track grooves respectively; Perhaps: have two to connect and symmetrical horizontal guide rail grooves on theeccentric nut 3, there are corresponding two guide rails the inboard of box body, and two guide rails place two guide-track grooves respectively.Because described sliding matching structure is conventional version, does not illustrate so give among Fig. 7.

Adopt above-mentioned pressure string assembly, when playing, the player as required, optionally push one and play key or several combination of playing key, control circuit board is according to the mapping relations table of playing key and pressedstring block 4 actions, pressure string assembly to respective numbers sends instruction, press the string assembly to allowcorresponding motor 1 rotate by corresponding direction according to instruction, for described each pressure string assembly, drivingeccentric nut 3 byscrew rod 2 moves axially alongscrew rod 2, allow be arranged on also action thereupon of corresponding pressedstring block 4 on theeccentric nut 3, make the traversing through end of pressedstring block 4 finish respectively to loosen or push corresponding string, realize the chord conversion.

Above-described only is three embodiments of the present invention.Should be pointed out that for the person of ordinary skill of the art under the prerequisite that does not break away from the principle of the invention, can also make some modification and improvement, these also should be considered as belonging to protection scope of the present invention.As: for three embodiment, play the quantity of key and the position is set all can determines flexibly as required, such as, play the front etc. that key also can be arranged on loam cake.

Claims (5)

1. a guitar is played servicing unit, hollow box body is arranged, be arranged on the box body and in order to this device is installed to the mounting structure on the guitar neck, be arranged on the some keys of playing on the box body, be arranged in the box body and with play the control circuit board that key is electrically connected, it is characterized in that: this device is pressed string mechanism in addition, press string mechanism to comprise the identical and some pressure string assemblies that be electrically connected with control circuit board respectively of structure, described pressure string assembly is arranged by the linescan method of lateral separation and longitudinal separation, so that form some square node structures, only there is one to press the string assembly on each joint of square node structure, respectively product region on the neck of described some pressure string assemblies and guitar is corresponding one by one on the position respectively, the quantity of the pressure string assembly in each row is identical with the quantity of string, the quantity of the pressure string assembly in each row is at least three, each presses the string assembly to comprise pressed string block at least, the base plate that the outer end of pressed string block passes box body exposes from box body, and the spacing between per two the adjacent pressed string blocks in each row is corresponding one by one on the position respectively with the spacing between per two adjacent strings.

2. a kind of guitar according to claim 1 is played servicing unit, it is characterized in that:

Described each pressure string assembly also comprises the motor that places in the box body, worm screw, the worm sector that is meshed with worm screw, vertical cantilever, limit switch, motor is installed in the box body and with control circuit board and is electrically connected, motor shaft is connected with worm screw is coaxial, the arc section upside engagement of worm and wheel, the arc section downside of worm gear respectively with the inner of pressed string block, the upper end of cantilever joins, on the worm gear with the arc section of worm gear away from the radially other end and box plate hinged, limit switch be installed in the box body and the position corresponding with cantilever, respectively there is a vertical limiting plate that extends upward and point to worm gear the length direction both sides of limit switch, and the lower end of cantilever places between two limiting plates.

3. a kind of guitar according to claim 1 is played servicing unit, it is characterized in that:

Described each pressure string assembly also comprises electromagnetic relay, the elastic sheet metal that places in the box body, one end of sheet metal has the arc fold bending section, the pairing center of circle of bending section is near the other end of sheet metal, the coil of electromagnetic relay is electrically connected with control circuit board, sheet metal joins by bending section and electromagnetic relay, the other end of sheet metal and the inner of pressed string block join, and electromagnetic relay, pressed string block are in the both sides of sheet metal respectively.

4. a kind of guitar according to claim 1 is played servicing unit, it is characterized in that:

Described each motor of pressing string assembly also to comprise to place in the box body, screw rod, the eccentric nut that is slidingly matched with box body, motor is electrically connected with control circuit board, motor shaft is connected with screw coaxial, one end of screw rod and eccentric nut spins, the other end of eccentric nut and the inner of pressed string block join, and motor, pressed string block are in the both sides of eccentric nut respectively.

5. play servicing unit according to each described a kind of guitar in the claim 1 to 4, it is characterized in that:

The interface that links to each other with computer is arranged on the described control circuit board; Described mounting structure comprises two semicircle collars, and two collars lay respectively at the upper and lower of the base plate of box body, homonymy one end of two collars and the base plate hinged of box body, the homonymy other end of two collars and the base plate clamping of box body.

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