Swivel mechanism for extending the sound range of a guitar by adding a string and a strumming wheel

Abstract

A stringed instrument in a construction similar to a guitar, with a neck (4), frets (3), and a soundhole (7) beneath which is a pivoting mechanism. This mechanism alternately brings a bow wheel and a striker wheel (16 and 18) into contact with the strings (5) via a drive and pivot crank (11) to excite them. The bow wheel and striker wheel are driven simultaneously by a gear mechanism (29). The resulting soundscape complements the guitar's sound with that of a bowed instrument similar to a hurdy-gurdy. The enclosed body, with its inner frame (20) and the spring-loaded pivot bearings (21) anchored within it, allows the two wheels to engage alternately directly below the strings.

Description

The invention relates to a mechanism by which a musical instrument resembling a guitar is extended in such a way that additional sounds resembling a stringed instrument can be produced, and furthermore a striking wheel which enables the rapid continuous striking of the strings with a sound range also exceeding that of the guitar. Stringed instruments, especially the guitar, have been known for centuries, are widespread, and their construction and sound are well-documented. WO 02013164318A illustrates the classic construction of a guitar and explains a new design and manufacturing method. FR 2 486 697 A1 describes the installation of an adjustable crank in a hurdy-gurdy of classic design. FR 2 556 119 A3 shows a setup in which a rotating wheel excites one or two strings via mechanical stops, which are then picked up electrically to produce tones. Patent CN 206833905U further describes a guitar enhanced with electromechanical elements that both press the frets on the fingerboard and strike the strings above the body. In this way, a microcontroller can play the guitar fully automatically. In terms of sound and playing technique, the guitar differs from stringed instruments like the violin or cello, which use a bow to draw the strings and thus create tones. The guitar's frets define the pitches, and the strings are plucked. In the latter, a bow is used to draw the strings, and the pitch is altered by the musician precisely shortening the strings. A special case of stringed instruments is the hurdy-gurdy, which was frequently described in medieval times. A cranked wheel sets the strings in motion, and keys are used to shorten them, thus varying the pitch. The sound of a plucked or struck guitar differs considerably from the sound of a bowed violin or hurdy-gurdy. The invention aims to expand the tonal range of a guitar through a mechanism that utilizes, firstly, a bow wheel, similar in function to that of a hurdy-gurdy, for sound generation, and secondly, a striking wheel, which is also rotated to produce a novel sound arising from the rapidly struck strings, most comparable to a guitar played in the flamenco style. The classical playing style of a guitar, as well as its normal sound, are retained thanks to the pivoting mechanism. The result of this mechanism is an instrument with a significantly expanded tonal range, which, however, is played exactly like a guitar and is therefore accessible to any guitarist without any learning curve. This novel instrument will henceforth be referred to as the "Gironda," derived from the Italian "Ghironda" for hurdy-gurdy. The mechanism and the resulting functions of the Gironda are defined in claims 1-7, which are described in detail below. The body of the Gironda contains a pivoting mechanism designed according to claim 1, the central rotating elements of which are a string wheel and a strike wheel as defined in claims 2 and 3. The purpose of the pivoting mechanism, according to claim 4, is to bring either the string wheel or the strike wheel, or neither, into contact with the strings of the Gironda. This allows the guitar to switch from the sound of a normal guitar to a stringed instrument sound or a flamenco-like sound. The crank from claim 5 is not only a drive unit but also a switching lever for changing between the functions of the Gironda. The crank drives the gear mechanism from claim 6, which sets the two wheels in rotation. The elements of the pivoting mechanism are anchored in the body of the guitar, which also serves as a resonator, as described in claim 7. The bow wheel of the Gironda is preferably made of wood, plastic, or entirely or partially of metal, has a thickness of 6 mm to 20 mm, but preferably 12 mm, and features a particularly smooth, polished edge. The bow wheel is mounted centrally on a shaft connected to the crank. Its design and finishing ensure that its radius is perfectly round, thus guaranteeing consistent string excitation. As with stringed instruments, the edge of the bow wheel is coated with rosin, achieving the combination of adhesion and smoothness necessary for reliable string excitation. The Gironda's pick wheel is preferably made of plastic, wood, or entirely or partially of metal. It has a thickness of 6 mm to 20 mm, but preferably 8 mm. It has at least one, preferably eight, but also up to 20 mounting points for plectrums. The pick wheel itself has a diameter a few millimeters, preferably 3 mm, smaller than the string wheel, so that the plectrums, and not the pick wheel itself, excite the strings. These plectrums are preferably reversibly connected to the pick wheel by clamping, screwing, or inserting them, and consist of hard, soft, or very soft materials that strike the strings in the desired manner. The angle of the plectrums can preferably be perpendicular to the tangent of the pick wheel, but can also deviate from it or even be adjustable to allow for different plectrums.The mounting for the striking elements is preferably longer on one side than on the opposite side to produce a softer strike in one direction of rotation, where the striking elements have an extended area for bending, while in the other direction they have a shortened area, producing a harder strike of the strings and thus a louder tone. The shape of the striking elements preferably resembles the triangular shape of a plectrum, but can also be round, rectangular, or needle-shaped. Striking elements are preferably made of flexible plastic or other materials with varying degrees of stiffness. The striking elements are attached to the striking wheel in such a way that they preferably protrude one millimeter, but also up to five millimeters, beyond the strings to be struck, in order to produce a tone upon contact. The pivoting mechanism is designed as follows. The pivot bearing of the mechanism is located centrally below the strings at the widest point of the body. Both axes of rotation of the string wheel and the hammer wheel are equidistant from this pivot bearing. The center of the pivot bearing thus forms an isosceles triangle with the centers of the string wheel and hammer wheel, which rotates around the pivot bearing. The detent points of the pivoting mechanism are chosen so that either the string wheel or the hammer wheel reaches the highest point closest to the strings. When engaged at this point, one wheel exerts an excitation on the strings, while the other wheel has sufficient clearance to rotate freely and without effect. A third detent point can be formed midway between the two excitation points, at which position neither wheel exerts an excitation on the strings.This free locking point can be used exclusively for playing as a classical guitar or for servicing the mechanism. To ensure correct contact of the Gironda's preferably six strings with the wheels, each string is individually guided in a fine height adjustment point, allowing each string to be precisely aligned with the wheels' circular path. The radius of both wheels is large, preferably 9 cm, but can also be smaller or larger, so that the arc described by the strings is as flat as possible and does not interfere with normal plucked playing of the Gironda. However, the wheel radius should not be too large, as this would also make the instrument's body very large. The pivoting mechanism engages at detents where the crank at the rear of the instrument swings into place. This is achieved either by two spring-loaded pivot points, located in front of and behind the pivoting mechanism, connecting it to the frame of the Gironda's body, or by the detents themselves encompassing and locking the pivot axis with spring-loaded clamps. The spring tension should preferably be chosen so that no unintentional pivoting out of the detents occurs during normal cranking. However, the spring tension should not be so strong that the effort required to pivot from one detent to the next becomes unpleasant. Adjusting the spring tension with adjustment screws allows for a comfortable locking force for the user. The pitch is achieved by pressing down the metal frets of the Gironda, similar to a guitar. It is also conceivable to construct the Gironda without frets, so that a continuous fingerboard runs along the neck of the instrument, played in the same way as a violin or cello. In the preferred version with frets, the distance between the frets is defined by the length of the strings from the nut to the bridge. The crank at the rear of the instrument is connected to the gearbox via a polished shaft, preferably made of stainless steel, with a diameter of 6 mm to 12 mm, but preferably 8 mm. The shaft is guided in ball bearings or plastic bearings to ensure quiet, precise, and low-friction operation. To facilitate changing the detents, the shaft is surrounded by one or more ball bearings at the detent point, which further reduces friction. The crank is shaped as a knobby, rotationally symmetrical handle that rotates eccentrically around the shaft on a radius of at least 40 mm, preferably 70 mm, but not more than 120 mm. The crank itself can be fixed to the handle or rotate on single or double ball bearings to eliminate the need to reposition the crank during playing. Preferably, the crankshaft acts directly on the striking wheel and indirectly, via a transmission, on the stop wheel, or vice versa. A transmission, preferably consisting of gears, toothed belts, or a belt drive, is used to bridge the gap between the axes of rotation of the striking wheel and the stop wheel. The gear transmission is preferably designed with helical gears, which ensure a continuous power transmission with low noise. A reduction or overdrive is conceivable; however, preferably both wheels rotate at the same speed. Motorizing the transmission is conceivable, but manual operation is preferred. The transmission can also be equipped with a flywheel, which can be designed either as a weighted striking or stop wheel, or as a third flywheel connected via a further reduction gear.This would allow the stringing function to be maintained for a certain period of time, during which the musician could simultaneously produce bowing and plucking sounds. The shafts of the gearbox are guided in ball or plain bearings to ensure low frictional resistance. It is conceivable to expand the Gironda with an internal microphone in the body or an electric pickup that is inserted between the neck and soundhole or at the bridge and allows the sound to be reproduced via an external electric amplifier. The present invention is described below in one possible embodiment with reference to Figures 1-4. Figure 1 shows a longitudinal section of the Gironda. Figure 2 shows a schematic alternation between the excitation of the strings by the bow wheel (left) and by the strike wheel (right). Figure 3 shows the central elements of the pivoting mechanism in a top view. Figure 4 shows the complete pivoting mechanism in a perspective view without the surrounding body. In Fig. 1, the preferably 6, but also 1 to 12 possible strings (5) of the Gironda are attached to the head of the neck (4) with a tuning peg (1) for each string and are tensioned to the correct pitch. The tensioned strings run over the nut (2) along the neck (4), over the playable frets (3), to the soundhole (7) in the upper tonewood (6), in which the string wheel (16) and the stop wheel (18) rotate. At the fine-adjustment point (9), the height of each individual string above the wheels is adjusted so that it touches or does not touch the wheels, depending on the playing style. The strings are anchored in the bridge (10). At the rear of the Gironda, the crank (11) is mounted, which, via the shaft (13), can reach the various detents (27) in the rear plate (12) and thus moves the entire pivoting mechanism and its elements (15-19). The crank drives the striking and stop wheel via the shaft (13) through the gearbox (29).To enable the locking from point to point, the pivoting mechanism is located in the spring-loaded bearings (14 and 21). As shown in Fig. 2, when the bow wheel (16) is pivoted to the right (25) to switch to the stop wheel, the center point of the bow wheel and stop wheel rotates along the circular path described by the pivot radius (23), which has the spring-loaded pivot axis (22) as its center point. The wheels rotate around the pivot angle (24), which, depending on the design and size, lies between 40° and 60°. In the right-hand image of Fig. 2, the schematically depicted stop wheel (18) touches the strings of the Gironda, while the bow wheel rotates freely without contact with the strings. Figure 3 shows the elements of the previously described process again in a production-oriented drawing. The striking wheel (16) has recesses that make the element lighter. In the illustrated design, the stop wheel (18) has 8 mounting points for stop elements (26 and 28). The front pivot frame element 19, which is connected to 2 further frame elements (15 and 17), forms the rigid frame of the pivot mechanism. Fig. 4 provides an overview of the entire swivel mechanism of the Gironda. For better visibility, the frame elements 20 and the rest of the body are hidden. In particular, the locking points 27 in the rear plate 12 are clearly visible in this version with 3 locking points. Reference symbol list 1 Tuning pin 2 Nut 3 Frets 4 Neck 5 Strings 6 Upper tonewood 7 Soundhole 8 Contact point of the lyre wheel 9 Fine height adjustment point 10 Bridge 11 Crank 12 Back plate with locking mechanism 13 Crankshaft 14 Rear spring-loaded pivot bearing 15 Rear pivot frame 16 String wheel 17 Middle pivot frame 18 Stop wheel 19 Front pivot frame 20 Body rib 21 Front spring-loaded pivot bearing 22 Pivot axis 23 Pivot radius 24 Pivot angle 25 Pivot direction 26 High part of the mounting point for the stop element 27 Detent points 28 Low part of the mounting point for the stop element 29 Gearbox

Claims

A stringed instrument with a neck (4), a body and several strings (5), characterized in that a device for extending the sound spectrum of the stringed instrument is arranged in the body, comprising a stringing wheel (16) and a striking wheel (18) as well as a pivoting mechanism by means of which the stringed instrument can be brought into a first state in which at least one string can be set into vibration by means of the stringing wheel (16) and into a second state in which at least one string can be set into vibration by means of the striking wheel (18). Stringed instrument according to claim 1, characterized in that the bow wheel (16) and the strike wheel (18) are simultaneously set in rotation via a transmission (29). Stringed instrument according to claims 1 and 2, characterized in that the bowing wheel (16) excites one, several or all strings by bowing, and furthermore that the striking wheel (18) accommodates at least one, preferably 8, but at most 20 striking elements of different stiffness in order to excite one, several or all strings by striking in rapid succession. Stringed instrument according to claims 1, 2 and 3, characterized in that the pivoting mechanism exchanges the string-exciting rotational paths (23) of the bow wheel (16) and the strike wheel (18) via a spring-loaded or fixed pivot point (14 and 21) and that the pivoting mechanism can be designed such that in a third state neither the bow wheel (16) nor the strike wheel (18) is in contact with the strings and the stringed instrument can be played as a guitar. Stringed instrument according to claims 1, 2 and 4, characterized in that a hand-operated crank (11) attached to the rear of the body, with a crankshaft (13) preferably made of metal, serves simultaneously as a drive element for the transmission (29) for the bowing wheel (16) and the stop wheel (18), but is also a switching lever for the pivoting mechanism. Stringed instrument according to claim 5, characterized in that the transmission (29) allows a rotation of the crank (11) to act directly on the string wheel (16) and drives the stop wheel (18) with a reduction, transmission or the same speed via preferably arrow-shaped gears but also toothed belts or belt drive. Stringed instrument according to claims 1, 4 and 5, wherein the body, preferably made of wood, serves both as an reinforcing resonating body and as the pivot point of the pivoting mechanism of the transmission (29) and the detent point of the switching lever.

Images