MUSICAL STRING INSTRUMENT

Abstract: A stringed musical instrument provided with a neck 1 and body 2 such as a guitar comprises a fingerboard 1a the frets 8 of which are retractable under the control of the player.

Description: Known guitar type musical instruments comprise a neck, on the surface of which a board known as a "fingerboard" is applied, and a resonance body over which the instrument strings are stretched. The body can be either of the acoustic type or electronic type, in this latter case it consisting of a solid block with one or more pick-ups which are disposed in proximity to the bridge to pick up the vibrations of the individual strings and feed them to suitable amplifiers. Each of these strings is stretched between two projections known respectively as the "bridge" and "nut", which define its useful length. During the playing of the music, the player can vary the useful or active length of each string by pressing it against the fingerboard. Each string can thus vibrate to emit sounds of different frequencies (musical notes) as a function of its tension and useful length, and of different intensities depending on the vibration amplitude. The instruments of the aforesaid type are divided into two categories depending on the timbre and playing requirements of the player. In this respect, known instruments are either provided or not provided with frets, such a fret being a generally metal bar disposed transversely below the strings and rigid with the upper surface of the fingerboard. In instruments provided with frets, the player presses with his fingers a string on the other side of a fret with respect to the body, so that the string rests against said fret and assumes a useful length equal to the distance between the fret and the bridge. By choosing the correct fret, he is able to obtain from the string a discrete series of notes of precisely defined timbre, and of metallic character due to the nature of the fret. In contrast, in instruments without frets, the useful length of the string is determined by the distance between the point at which the player keeps the string pressed against the fingerboard and the bridge, the absence of the fret meaning that the sound assumes a much softer character. The player has therefore the possibility of choosing at his own discretion the useful length of the string without the limitation due to the predetermined position of the frets. Basically, the two instruments with or without frets emit sounds of very different characteristics and timbre, and the same player while playing one and the same piece may require instruments with and without frets at different moments. At the present time, in particular for bass guitars, each player has two instruments available, and where the playing pattern allows it he replaces one instrument with the other according to requirements. However, this greatly limits his playing range in that the rhythm of the music does not always allow him the time necessary for making the required replacement. The present invention relates to an instrument of the aforesaid type, and in particular a base guitar, either electronic or acoustic, which obviates the aforesaid drawbacks in that it can be converted from an instrument with frets to an instrument without frets. Such a instrument is shown in US-A-429736, where the neck is provided with retractable frets which can be raised above the upper surface of the fingerboard under the control of the operator. The aim of the presebt invention, is to improve the fret retraction mechanism to allow a quick, singlehand control of the rovement of the frets between the extended and the retracted posiotions. This aim is achieved by the instrument as characterised in the claims. The invention is below described and one embodiment thereof is illustrated hereinafter by way of non-limiting example with reference to the accompanying drawings. These relate to an electric bass guitar, but it is apparent that the invention can be applied without restriction to any type of stringed instrument provided with a neck and body. Figure 1 is a plan view of an electric bass guitar. Figure 2 is a side view thereof. Figure 3 is a section on the line III-III of Figure 1. Figure 4 is a section on the line IV-IV of Figure 3. Figure 5 is a section on the line V-V of Figure 3. The aforesaid figures show an instrument consisting of a neck 1, at the end of which there is provided a solid block 2 forming the body and carrying the pick-ups 3 and the bridge 4. At the opposite end, the fingerboard 1a fixed on to the neck 1 comprises a projection 5 known as the "nut". The strings 6 are stretched between the bridge 4 and projections 5, and their tension can be adjusted by the adjustment screws 7, one for each string. On the top of the fingerboard 1a there is disposed a series of frets 8, of the usual number and distribution for the instrument, each of them being inserted into a seat8Oin which it can slide, to be raised above the upper surface of said fingerboard or to be lowered at least to the level thereof. The frets 8 are in the form shown in Figure 5, and comprise an upper bar provided with a central stem 9 and two projections 10 to the sides of the stem. The stem 9 opens into a lower cavity of the neck, in which a spring 11 urges it downwards such that the fret lies level with the finderboard. In a position below the projections 10, the neck comprises two longitudinal cavities 12 into which two shafts 13 are inserted. In correspondence with each fret, each shaft 13 is provided with a cam 14 which acts on the respective projection 10, and when the shaft is rotated causes the fret 8 to rise above the level of the fingerboard. For this purpose, each shaft 13 is provided with a gear wheel 15. The two wheels 15 engage with the same central pinion 16, on the pin of which there is disposed an operating knob 17 at the end of the neck. Between the body 2 and the end of the neck, in an opposite position to the strings 6, there is provided a stiffener 18 which prevents deformation of the neck induced by the tension of the strings. A detailed description of the other parts of the instrument, such as the means for fixing the strings,the electrical part and other undefined parts, is omitted as these are usual. The operation of the instrument is apparent, and allows the player to change from the configuration with frets to the configuration without frets or vice versa, in a very short time of the order of one second by simply rotating the knob 17 through little more than one quarter of a revolution.

Claims: Musical string instrument of the type provided with a neck (1) carrying a fingerboard (1a) and a solid body (2) carrying pick-ups (3), the neck (1) and fingerboard (1a) comprising a series of transverse seats (80) each of which is arranged to slidingly receive a fret (8), and means simultaneously operable by a single external control (17) for causing all the frets (8) to translate simultaneously such that they become positioned projecting from the upper surface of the fingerboard or completely retracted into the respective seat, characterised in that it comprises: shaft means (13) provided with a plurality of cams (14) rotatably disposed within said neck (1), in a position below the frets (8), for engaging and actuating said frets (8); spring means (11) for biasing said frets (8) to a retracted position and into engagement with said cams (14) of said shaft means (13); and means (15, 16) for rotating said shaft menas (13) for simultaneously actuating said plurality of frets (8)to an extended or retracted position, said means (15, 16) being operable by said external control (17). The instrument according to claim 1, characterised in that said shaft means (13) comprises two parallel shafts (13) each provided with a gear wheel (15) at one end, and said means for rotating said shafts (15) comprises a pinion (16) engaging said gear wheels (15) of said shafts (15), said external operating member (17) being connected to said pinion (16) The instrument according to claim 2, characterised in that said external operating member (17) comprises a knob (17) extending from the end of said neck (1), and connected to said pinion (16) for rotating said pinion (16). The instrument according to claim 2, characterised in that it comprises a stem (9) extending from each fret (8) with each stem (9) terminating in a cavity provided in the lower part of the neck (1), in which a spring (11) retains it with the respective fret (8) in its lowered position. The instrument according to claim 4, characterised in that said stem of each fret (8) is positioned in between said two parallel shafts (13) and each fret (8) is provided with two projections (10) wherein one projection (10) engages with one cam (14) of one shaft (13) and the other projection (10) engages with one cam (14) of the other shaft (13).

Inventors: PIGOZZI, GABRIELE
Applicants: PIGOZZI, GABRIELE
Application year: 1987
Main classification: G10D1
IPC codes: G10D1, G10D3