Abstract:
A device for setting the tension in a string of a stringed musical instrument whereby a musician can instantly retune the string to play either one of two predetermined notes by merely actuating a lever. The device is preferably attached between the tailpiece or body of the instrument and an end of the string. The element of the tuner to which the string is attached (a string anchor) moves with a rectilinear motion to change the string tension. Two embodiments are disclosed, one of which used a rotating cam to position the string anchor, and the other of which uses a two-bar linkage to position the string anchor.

Description:
RELATED APPLICATIONS 
     This application claims the benefit under 35 USC §119(e) of the filing date of U.S. Provisional Patent Application Ser. No. 61/631,605, entitled “Musical Instrument Retuning Device” filed on Jan. 9, 2012. By this reference, the contents of Application Ser. No. 61/631,605 are incorporated herein in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Music, as composed and played in the western world, is almost universally based on the use of harmonically related notes, i.e., the notes are selected from groups of notes, the frequencies of which groups differ from each other by factors of two, i.e., an octave. The individual notes within each octave (in the western world) are commonly defined by a twelve-tone equal-tempered scale. In this scale, the adjacent notes are related by the twelfth root of two, and alternate notes are named C, D, E, F, G, A, and B (with C being the lowest note). The semi-tones between are termed “sharp” or “flat”. Conventionally, the octaves are numbered (1, 2, 3, etc.) such that the note A4 has a frequency of 440 Hz. 
     Stringed musical instruments, such as the upright bass, viola, violin, guitar, etc. each include a specified number of stretched strings, each of which produces one of the desired notes. The note produced by a particular string depends on a number of factors, including the mass of the string, its length, and the tension in the string. Different instruments are designed to produce particular notes. An upright bass, for example, usually has four strings, tuned to produce the notes E1, A1, D2, and G2. Other instruments have the same or a different number of strings, generally tuned to provide specific notes as appropriate to the type of instrument. 
     While instruments that are tuned in the historically customary manner can, and do, provide much pleasing music, sometimes a musician may wish that his or her instrument is capable of playing other notes. For example, if an upright bass player were able (during a performance) to retune the low E1 note to D1, more harmonic variations would be possible, which could enhance the musical performance. Or, if the upright bass tuning could be instantly changed to fifths (C1, G1, D2, A2—cello tuning for bass) from the standard fourths tuning (E1, A1, D2, G2—standard bass tuning), the instrument would have substantially increased versatility. 
     There have been a number of attempts to produce devices that provide the foregoing functionality, but they generally have not been completely satisfactory. In many cases, it has not been easy or convenient to switch from one tuning to another during a performance, so that the advantage of the extra notes potentially available has not been easily accessible. In other cases, significant modification of the basic instrument is required, which is resisted by most musicians. Other problems have also arisen. 
     SUMMARY OF THE INVENTION 
     While the present invention has applicability to any stringed instrument (acoustic or electric), for purposes of convenience and ease of presentation, the invention is described here primarily as being applied to an acoustic upright bass. The physical size of various stringed musical instruments varies substantially, so it will be understood that, similarly, the physical size and other construction details of embodiments of the invention may vary. 
     In one presently preferred embodiment of the invention, the invented device can be thought of as part of the string assembly. In this embodiment, a string with one of the invented tuners attached to one end is hooked onto the instrument tailpiece, passed over the bridge, stretched along the instrument neck, and wrapped around the post of a tuning machine at the far end of the instrument neck. Actuating a lever on the invented tuner changes the length of the tuner by a predetermined amount, and thereby changes the tension in the string, and correspondingly its natural frequency. Each tuner changes the frequency at which one string vibrates; by installing an invented tuner at the end of each string, the tuning of any or all strings of an instrument may be changed by the musician, even during a performance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a plan view of a portion of the body of an acoustic upright bass musical instrument with four of the invented tuners installed thereon. 
         FIGS. 2A and 2B  each depict a right side view of one of the invented tuners as installed on the instrument shown in  FIG. 1 .  FIG. 2A  shows the tuner set to its high pitch position, and  FIG. 2B  shows its low pitch position. 
         FIG. 3  is an exploded view of one embodiment of the invented tuner. 
         FIG. 4A  is a detail view of one form of cam that may be used in connection with the invention. 
         FIG. 4B  is a detail view of a second form of cam that may be used in connection with the invention. 
         FIG. 5  is a right side view of one embodiment of the invention, the tuner being shown in its low pitch condition.  FIG. 5A  is a complete tuner, while  FIG. 5B  shows the tuner as in  FIG. 5A , with the actuating lever removed. 
         FIG. 6  is a right side view of the embodiment of the invention as shown in  FIG. 5 , the tuner being shown in its high pitch condition.  FIG. 6A  is a complete tuner, while  FIG. 6B  shows the tuner of  FIG. 6A  with the actuating lever removed. 
         FIG. 7  is a plan view of six instances of the invented tuner as mounted on a guitar. 
         FIG. 8  is a right side view of one of the tuners of  FIG. 7 . 
         FIG. 9  is a right side view of a second embodiment of the invention, shown in its high pitch condition. 
         FIG. 10  is a right side view of a second embodiment of the invention, shown in its low pitch condition. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows four tuners  10  according to one embodiment of the invention, each with a string  14  attached, and each hooked onto the tailpiece  11  of an acoustic upright bass musical instrument  12 . This installation permits all four of the strings of the instrument to be instantly tuned, each to produce one of two preset tones. The actuating lever  13  of each tuner is individually accessible to change the tension of the corresponding string  14 , and thereby its tuning. The ability of a tuner to be attached to and removed from an instrument without using tools is referred to herein as being “removable” or “removably attached”. 
       FIGS. 2A and 2B  each show a right side view of the installation for one of the strings shown in  FIG. 1 , where  FIG. 2A  shows the actuating lever  13  in its high pitch position, and  FIG. 2B  shows the actuating lever  13  in its low pitch position. Also seen (in both  FIG. 2A  and  FIG. 2B ) are the bridge  15  and string  14 . Each string  14  has a “ball”  16  attached to its end, as is customary in stringed musical instruments. The ball  16 , instead of being attached to the tailpiece of the instrument, as is the usual case, is attached to the invented tuner, i.e., to string anchor  27 , as will be described later. 
       FIG. 3  is an exploded view of one embodiment of the invention where a base member  20  is seen having a hook  21  which is fastened thereto by screws  22 . Three holes  23  are preferably provided in the base member tail, which allows the hook to be installed in more than one location, as might be convenient for installation on different instruments. The hook  21  is intended to hook over the tailpiece of the instrument in place of the string ball that ordinarily is in that position. The base member  20  carries a rotatable cam  24 , which is secured to the base member by screw  25 . The cam  24  is rotated, at the will of the musician, by actuating lever  13 . 
     A portion of string anchor  27  passes between base member  20  and rotatable cam  24  and further includes surface  29  on which cam surface  28  rides. Tension in the string  14  causes string anchor  27  to move substantially rectilinearly as the positioning means (cam  24 ) is rotated. The string anchor includes an opening  30 , into which the ball  16  is inserted; the string exits the string anchor through slot  31 . A ridge  32  is preferably provided at the edge of opening  30  to keep the ball from sliding out of the opening. 
     While not essential, it is preferred that a small amount of lubricant, such as white lithium grease, be placed between the string and the bridge to aid in the smooth operation of the tuner. 
     The position of string anchor  27  with respect to base member  20  is determined by the position of cam  24 . As seen in  FIG. 5  (the low pitch position), the string anchor is in its furthest right position (with respect to the drawings). As seen in the drawings, this corresponds to the actuating lever  13  “up” position. Conversely, in  FIG. 6  (the high pitch position), the actuating lever, in its “down” position, can be seen to correspond to the string anchor being in its furthest left position. The changes in string anchor position are brought about by the cam surface  28  acting on follower surface  29  (as can be seen in  FIG. 4 ). Tension in the string causes the follower surface  29  to always be in contact with the cam  24 . In the drawings, the cam surface  28  appears sharp, but in practice, it is preferably somewhat rounded. 
     The invented tuner is intended to provide a musician with the capability of instantly retuning a string of a musical instrument to provide one of two notes, one (the high pitch) corresponding to positioning the actuating lever  13  “down”, i.e., against string anchor  27 , and the second (the low pitch) corresponding to positioning the actuating lever  13  “up”, where its motion is limited by the adjusting screw  40 . As seen in  FIGS. 6A and 6B , the tuner is shown in its high pitch position, with lever  13  pushed down as far as it will go. In  FIGS. 5A and 5B , the tuner is set to its low pitch position, where the upward position of actuating lever  13  (and thereby the location of string anchor  27 ) is limited by adjusting screw  40 . 
     When in the high pitch position, the note that a particular string will provide is preferably set by adjusting the instrument&#39;s tuning machine at the end of the neck. The low pitch for that string is then set by adjustment of adjusting screw  40 . A spring  41  is preferably provided to avoid the problems that might arise due to vibration when the instrument is played. 
       FIG. 4B  illustrates a slightly different shaped cam  24 ′, including a more gently curved cam surface  28 ′. Other modifications and embodiments of the present invention are possible within the spirit of the claims, such as (but not limited to) other methods for fastening the tuner to the musical instrument, as by using screws or other known fastening methods, instead of the hook shown in the embodiment of  FIGS. 1-6 . For example,  FIG. 7  depicts six instances of an embodiment of the invention ( 10 ′) fastened to the body  50  of a guitar using screws ( 51 ).  FIG. 8  is a right side view of the embodiment shown in  FIG. 7 . All such modifications as fall within the claims, including equivalents thereto, are intended to be covered hereby. 
       FIGS. 9 and 10  depict a second embodiment of the invention wherein a different positioner construction is used. In this embodiment, a two-bar toggle linkage is utilized to position the string anchor with respect to the base member. An “over-center” toggle, as shown, is preferred, but a two-bar linkage, without the over-center feature could also be used. As seen in  FIGS. 9 and 10 , the base member  60  can be seen equipped with a hook  21  for engaging the instrument tailpiece, just as the first embodiment. A string anchor  61  includes an opening  30 , a retaining ridge  32  and slot  31  (to accept a string and ball), as in the first embodiment. Instead of a cam to control the position of the string anchor, this embodiment uses a two-bar linkage ( 62 ,  63 ). When actuating lever  64  is in its down position ( FIG. 9 ), the bar  63  rests against stop  66 , limiting the motion of string anchor  61  (which is being pulled to the right by string tension). When actuating lever  64  is in the up position ( FIG. 10 ) string tension drives link  63  against adjusting screw  65 , which sets screw anchor position in the low pitch position. 
     Tuning of the second embodiment is the same as for the first embodiment. First, the desired high pitch note is set by using the tuning machines or pegs at the end of the neck, and then the desired low pitch note is set by adjusting screw  65 .