Abstract:
A device and method for reducing wear and stress in the string of a stringed instrument, such as a guitar. Certain stringed instruments are strung by advancing strings through string apertures in the body of the instrument. The device includes tubular sleeves that are placed into the string apertures. As the instrument is strung, the strings of the instrument are tightened. When tightened, the strings abut against and bend around the tubular sleeve. The tubular sleeve has a curved surface against which the strings bend. This lowers stress concentrations in the strings at the points of the bend. Furthermore, the tubular sleeves are made from a material that is softer than the material of the instrument&#39;s strings. Accordingly, as the instrument&#39;s strings wear against the sleeves, the sleeves experience the wear more so than the strings.

Description:
RELATED APPLICATIONS 
   This Application is a Continuation-In-Part of application Ser. No. 09/776,597, which was filed on Feb. 5, 2001 now abandoned. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   In general, the present invention relates to instrument strings of the type that are most commonly used on modern electric guitars. More particularly, the present invention relates to guides that are used in conjunction with guitar strings to help the guitar strings resist breakage during use. 
   2. Description of the Prior Art 
   Hand strummed stringed instruments have been in existence for many centuries. During that period of time, such stringed instruments have evolved into many different forms. One of those forms came is the acoustical guitar. Acoustical guitars have a hollow body and a neck that extends from the body. A plurality of strings are strung from the neck across an opening in the body. As the strings are strummed, the vibration of the string resonates in the hollow body of the guitar, thus amplifying the sound of the string. 
   In an acoustic guitar, the strings are attached to the top of the neck with tuning pegs or geared tuning mechanisms. These devices are used to adjust the tension in the guitar strings. At the opposite end of the guitar strings, the strings attach to a saddle block that firmly anchors the guitar strings in place. 
   In the middle of the twentieth century, the design of guitars again evolved, thereby introducing the electric guitar. Originally, electric guitars where merely acoustical guitars with an acoustical transducer placed within the hollow body of the guitar. The acoustical transducer was connected to an electrical amplifier and a speaker that reproduced the sound of the guitar. 
   As electrical guitar designs matured, the entire design of the guitar was designed around its electrical components. In modern electrical guitar designs, the body of the guitar is no longer hollow. Rather the body of the guitar is solid. Positioned below the stings is now an electrical pick-up. The electrical pick-up directly converts the vibrations of the guitar strings into corresponding electrical signals that can be amplified, altered and broadcast by other electronic devices. 
   Along with the advent of the solid guitar body came a new way to mount guitar strings to the guitar body. Many modern electrical guitars have apertures formed through the solid body. The apertures have a diameter just wide enough to enable the passage of a guitar string through the aperture. Specialized guitar strings are produced for use with such electric guitars. The specialized strings terminate at one end with enlarged end caps. Such strings are shown in U.S. Pat. No. 5,913,257 to Schaller, entitled Method Of Manufacturing Guitar Strings And Guitar Strings Resulting From Such Method. The strings can pass through the apertures in the guitar, but the end caps cannot. As such, by threading such a specialized guitar string through an aperture in the guitar body, the guitar string becomes firmly anchored in place. 
   Electric guitar strings are passed from the rear of the guitar body toward the front of the guitar body. As the strings pass through the guitar body, the guitar strings fold over a bridge assembly before extending across the guitar body and up to the neck of the guitar. The bridge assembly in an electric guitar typically contains metal saddles. The guitar strings abut and bend against the saddles as the guitar strings turn toward the neck of the guitar. 
   As the guitar is played, the strings vibrate. Some of this vibration is experienced at the interface between the guitar strings and the saddles in the bridge assembly. As the guitar strings vibrate, the strings wear against the saddle. Furthermore, the point of contact against the saddle is a stress concentration point for the guitar strings. Eventually, the guitar strings wear to a point where the stress on the string causes them to break. The break on the string is typically right at the point where the string contacts the saddle. 
   In the prior art, there have been different techniques used that are intended to help a guitar string resist breakage. One technique is to reinforce the guitar string at the point where the guitar string contacts the saddle in the bridge assembly. Such prior art techniques are exemplified by U.S. Pat. No. 4,581,976 to Ball, entitled Reinforced Musical Instrument String. This technique works, however, the reinforcements add significantly to the cost of the guitar strings. 
   Another technique used to reduce guitar string breakage, is to increase the curvature of the saddle at the point where the string abuts the saddle. Such prior art techniques are exemplified by U.S. Pat. No. 4,960,027 to Dunwoodle, entitled Bridge For A Stringed Instrument. Such devices do reduce the number of guitar string breakages. However, the guitar string still does wear against a metal saddle and does eventually wear to a point of breakage. 
   Recognizing that wear is caused by the contact of the metal guitar string against the metal saddle, pads have been developed that are intended to be placed between the string and the saddle. Such prior art pads are exemplified by U.S. Pat. No. 5,465,643, entitled Guitar String Support. The problem associated with such pads is that they are very difficult to correctly position between the guitar string and the saddle. Furthermore, the pad conforms to the shape of the saddle, thus the guitar string still wears against a salient point. This often causes the pad to prematurely wear away. This effects the protection provided to the guitar strings by the pads and the tuning of the guitar strings. 
   A need therefore exists for a device that can prevent wear between a guitar string and a saddle of a bridge assembly, yet is easy to install and is inexpensive. This need is provided by the present invention as described and claimed below. 
   SUMMARY OF THE INVENTION 
   The present invention is a device and method for reducing wear and stress in the string of a stringed instrument, such as a guitar. Certain stringed instruments are strung by advancing strings through string apertures in the body of the instrument. The present invention device consists of tubular sleeves that are placed into the string apertures. As the instrument is strung, the strings of the instrument are tightened. When tightened, the strings abut against and bend around the tubular sleeves. Each tubular sleeve has a curved surface against which a string bends. This lowers stress concentrations in each string at the point of the bend. Furthermore, the tubular sleeves are made from a material that is softer than the material of the instrument&#39;s strings. Accordingly, as the instrument&#39;s strings wear against the sleeves, the sleeves experience the wear more so than the strings. By reducing the stress and the wear on the instrument&#39;s strings, the usable life of the instrument&#39;s strings is dramatically increased. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is made to the following description of an exemplary embodiment thereof, considered in conjunction with the accompanying drawings, in which: 
       FIG. 1  is a perspective view of an electric guitar in accordance with the present invention; 
       FIG. 2  is a cross-sectional view of the area of a prior art electric guitar in the area surrounding the bridge assembly; 
       FIG. 3  is a cross-sectional view of the area of an electric guitar, in accordance with the present invention, in the area surrounding the bridge assembly; and 
       FIG. 4  is cross-sectional view of a tubular sleeve in accordance with the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Although the present invention device and method can be used on many stringed instruments, such as violins, banjos, mandolins and the like, the present invention device and method are particularly well suited for use on electric guitars. Accordingly, the illustrated examples of the present invention device will show applications where the device is being used to prolong the life of a guitar string strung onto an electric guitar. 
   Referring to  FIG. 1 , an exemplary embodiment of an electric guitar  10  is shown. The electric guitar  10  has a solid body  12  and a neck  14  that extends from the body  12 . Geared tuning mechanisms  16  are attached to the end of the neck  14 . Toward the bottom of the solid guitar body  12  is located a bridge assembly  18 . The bridge assembly  18  includes a tremolo  20  and a set of saddles  22  for pulling the guitar strings  24  taut against the tremolo  20 . Beneath the bridge assembly  18  is a bank of apertures  25 . There is one aperture  25  for each string  24  of the guitar  10 . The saddles  22  in the bridge assembly  18  align over the apertures. 
   The free end of the guitar strings  24  are passed through the apertures from the back side of the guitar body  12 . Each of the guitar strings  24  terminates at one end with an enlarged end cap  26 . The end cap  26  is too large to pass fully through the apertures  25  in the guitar body  12 . The free end of each guitar string  24  is at the end of the guitar string  24  opposite the end cap  26 . The free end of each guitar string  24  is passed fully through the guitar body  12 . The free end of each guitar string  24  is then advanced through a corresponding saddle  22 , over the tremolo  20  and to a corresponding geared tuning mechanism  16 . As the tuning mechanisms  16  apply tension to each of the strings  24 , the guitar strings  24  are pulled taut between the bridge assembly  18  and the geared tuning mechanisms  16 . 
   Referring to  FIG. 2 , it can be seen that with a traditional prior art configuration, each guitar string  24  extends through an aperture  25  and through the bridge assembly  18 . Once the guitar string  24  is installed, the guitar string  24  is pulled taut over the tremolo and abuts against the corner of the saddle  22 . 
   Referring now to  FIG. 3 , it can be seen that the configuration of the present invention includes a protective tubular sleeve  30 . The protective tubular sleeve  30  is made of a material that is softer than the metal of the guitar string  24 . The tubular sleeve  30  can be made from a soft metal, such as brass, bronze, aluminum or an aluminum alloy. However, preferably, the tubular sleeve  30  is made of a synthetic material that is resistant to wear. Although compositions such as Kevlar, and Teflon can be used, a preferred material is Surlyn, which is the wear-resistant material commonly used on the exterior of modern golf balls. 
   The protective tubular sleeve  30  is comprised of a head section  32  and a neck section  34 . The neck section  34  has an exterior diameter that is small enough to fit into a string aperture  25  in the solid body  12  of the guitar  10 . The neck section  34  can have a constant external diameter or can be slightly tapered to help the neck section  34  pass into one of the apertures  25 . The head section  32  of the protective tubular sleeve  30  is enlarged. The external diameter of the head section  32  is larger than that of the string aperture  25  in the guitar body  12 . As such, when a protective tubular sleeve  30  is placed into one of the string apertures  25  in the guitar  10 , the protective tubular sleeve  30  comes to rest in the string aperture  25  at the transition point between the head section  32  and the neck section  34  of the protective tubular sleeve  30 . 
   On the interior of the protective tubular sleeve  30  is a conduit  36 . The conduit  36  has a diameter large enough to accommodate a guitar string. A single sized conduit  36  can be used that is sized to accommodate the largest of the guitar strings, or different sized conduits  36  can be used that are sized to accommodate the different diameter strings  24  of the guitar  10 . 
   The diameter of the conduit  36  is constant until the conduit approaches the top of the head section  32  of the protective tubular sleeve  30 . At this point, the conduit flares out. The result is that a curved surface is formed on the inner edge  38  of the conduit  36  at the top of the head section  32 . The curved inner edge  38  preferable has a radius of curvature at least as large as the diameter of the neck section  34  of the tubular sleeve  30 . 
   To install the protective tubular sleeves  30 , the strings  24  are removed from a guitar and the tubular sleeves  30  are inserted into the apertures  25  in the guitar  10 . The protective sleeves  30  are inserted through the saddles  22 , with the head sections  32  of the protective sleeves  30  facing upwardly. The free ends of the strings  24  are then advanced through the conduits  36  in the protective sleeves  30 . In an alternate installation step, the free ends of the guitar strings  24  can first be advanced through the string apertures  25  in the guitar body  10 . The protective tubular sleeves  30  can then be threaded onto the free ends of the strings  24 . The strings  24  can then be used as guides to advance the protective tubular sleeves  30  down into the apertures  25  in the guitar body  10 . 
   Once the protective tubular sleeves  30  are in place, the free ends of the strings  24  are advanced over the tremolo  20  and to the geared tuning mechanisms  16  ( FIG. 1 ) on the neck of the guitar  10 . As can be seen, once the protective tubular sleeves  30  are in place, each string  24  folds around the curved inner edge  38  of the protective tubular sleeve  30 . As a result, each guitar string  24  is prevented from wearing against a salient point of the saddle  22 . Furthermore, the metal strings  24  are wearing against the synthetic material of the tubular sleeves  30 . Thus wear of the strings  24  themselves is reduced and the number of broken strings caused by wear and stress is proportionally reduced. 
   Furthermore, since the protective tubular sleeves  30  are tubular, they are symmetrically disposed around the guitar strings  24  within the apertures  25 . Accordingly, they have no one proper orientation that must be adhered to during installation. This allows the protective tubular sleeves  30  to be rapidly and simply installed. 
   Referring now to  FIG. 4 , it can be seen that each protective tubular sleeve  30  has a head section  32  with a certain diameter and a neck section  34  with a certain length. The length of the neck section  34  serves little purpose other than to hold the head section  32  concentrically within a guitar body string aperture. As such, the length of the neck section  34  of the protective tubular sleeve  30  can have any length greater than half the diameter of the head section  32 . The maximum length of the neck section  34  is not to exceed the length of the string aperture into which the protective tubular sleeve  30  is being placed. 
   The conduit  36  defined by the tubular sleeve  30  expands as the conduit moves from the neck section  34  of the tubular sleeve  30  to the head section  32  of the tubular sleeve  30 . This produces the curved inner edge  38  against which a guitar string is biased. The curved inner edge  38  has a radius of curvature at least as large as the diameter of the neck section  34  of the tubular sleeve  30 . As a result, the curved inner edge  38  has no sharp corners against which a guitar string will wear. 
   From  FIG. 4 , it can be seen that each tubular sleeve  30  has a top end  41  and a bottom end  42 , The central conduit  36  extends from the top end  41  to the bottom end  42 . The central conduit  36  has a first diameter in the neck section  34  of the tubular sleeve  30 . The central conduit  36 , however, expands through the head section  32  to a larger second diameter at the top end  41 . The expansion occurs along the curved inner surface  38 . The top end  41  of the tubular sleeve  30  meets the curved inner surface  38  of the central conduit  36  at a tangent. As a result, there is a smooth curving transition from the top end  41  of the tubular sleeve  30  into the central conduit  36 . No edges are therefore present against which the guitar string can wear. 
   The above embodiment described the use of metal guitar strings placed in a wooded guitar. Such descriptions are merely exemplary. The use of the tubular sleeves can also be used with plastic guitar strings and other synthetic material strings. Furthermore, the tubular sleeves can be used in instruments having metal or plastic bodies. The material of the instrument or string is not relevant. Rather, the present invention is directed toward relieving stress at the points where the strings abut against the instrument and cause wear in the string, 
   It will be understood that the embodiment of the present invention device and method described is merely exemplary and a person skilled in the art can make many variations to the embodiment shown without departing from the scope of the present invention. For example, the prior art is replete with different types of synthetic materials that can be used in the fabrication of the tubular protective sleeves. Any such material can be used provided it is softer than the metal of the guitar string yet has an expected wear life longer than that of the guitar string. All such variations, modifications and alternate embodiments are intended to be included within the scope of the present invention as defined by the appended claims.