Abstract:
A guitar sting tension device for an electrical guitar retrofitted with a vibrato unit to prohibit displacement of the strings on the bridge of the guitar consisting of a rotatable string retention bar, two rotatable connection arms, a pivotal anchor collar with recessed aperture; and a mounting adapter to affix the vibrato unit to the guitar.

Description:
TECHNICAL FIELD 
     The present invention relates to optional effects for electrical guitars, in particular, the device allows for retrofitting a vibrato unit to an electric guitar. 
     BACKGROUND OF THE INVENTION 
     Electric guitars are sometimes manufactured with an optional vibrato unit to provide a mechanism that allows the guitarist to stretch or loosen the guitar strings while the guitar is being played. This provides a fanciful variation to the sounds of the guitar by allowing the guitar player to alter the pitch by moving the lever mechanism of the vibrato unit. In the past, if a guitar owner wanted a guitar with a vibrato unit, the owner would have to procure a guitar that was manufactured with such a vibrato. 
     A guitar owner may attempt to mount a vibrato unit by drilling holes in the deck of the guitar to screw on a vibrato unit. However this could affect the tone of the instrument and could also affect the structural integrity of the deck, especially in hollow bodied guitars, which have thin wooden decks. Additional holes in the guitar may also affect the value of the guitar. A guitar owner did not have a commercially available option to effectively add such a vibrato mechanism to an existing electric guitar. 
     On an ordinary guitar, the strings are held in place on the face of the guitar at the tailpiece. To retrofit a vibrato unit onto an electric guitar, the existing tailpiece, aft of the bridge, must be removed to accommodate the installation. This because the vibrato unit would then serve to hold in place the end of the strings. The removal of the tailpiece typically leaves either mounting bolts sticking up from the face of the guitar or holes in the deck. This is cosmetically degrading and affects the value of the guitar. 
     Also, the substitution of the vibrato unit for the tailpiece typically alters the length of the strings between the bridge and the terminal attachment point. For hollow bodied guitars, the length of the strings is greater with the vibrato unit than with the tailpiece. The strings also approach the bridge from there connection with the vibrato at a lesser angle than with the tailpiece. This results in lesser down force or tension, which further results in problems keeping the strings in place on the bridge when the vibrato unit is activated. It also affects the action of the strings at the neck. The lesser angle further provides problems retaining the stings on the bridge when the guitar is being played. The present invention provides a means for maintaining the proper tension on the strings with the proper angle as well. 
     Additionally, the removal of the tailpiece leaves either an unsightly set of holes or studs on the face of the guitar where the tailpiece was connected. Leaving holes in the guitar face will alter the tone of the instrument as well as provide an unsightly guitar. 
     Therefore, there exists a need to create a device that would allow the retrofitting of a vibrato mechanism to an electric guitar that provides downward tension on the strings and utilizes the former connection method of the discarded tailpiece. 
     SUMMARY OF THE INVENTION 
     The present invention provides an electric guitar string tension device including a rotatable retention bar to rest on the guitar strings, two rotatable support arms at each end of the retention bar, two pivotal attachment collars on the other end of the support arms and two connection bolts to affix the attachment collars to the electric guitar. In an alternate construction, the retention bar and support arms are fabricated as one piece. 
     In another embodiment a mounting bracket is utilized to affix a vibrato unit to the electric guitar including an attachment means. 
     In yet another embodiment, a kit combining the electric guitar string tension device together with a mounting bracket and assorted bolts, nuts and screws is contemplated. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the assembled guitar string tension device; 
         FIG. 2  is a perspective view of an electric guitar retrofitted with a vibrato unit with the string tension device installed in accordance with this invention; 
         FIG. 3  is a partial perspective view of the guitar shown in  FIG. 2  indicating how the components of the string tension device are assembled; 
         FIG. 4  is a plan view of the string tension device; 
         FIG. 5  is a full side view of the string tension device shown in  FIG. 4 ; and 
         FIG. 6  is a cross-sectional view along line  6 - 6  of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Unless defined otherwise, all terms used herein have the same meanings as are commonly understood by one of skill in the art to which this invention belongs. All patent, patent applications and publications referred to throughout the disclosures herein are incorporated by reference in their entirety. In the event that there is a plurality of definitions for a term herein, those in this section prevail. 
     The term “attachment means” as used herein refers to a means for securely holding one component to another by a variety of methods known by one skilled in the art such as for example bolts and nuts to attach a vibrato unit to a mounting bracket. 
     The term “affixed” as used herein refers to a means for fastening or connecting, permanently or reversibly, one element of the invention to another element by a variety of methods know by one skilled in the art such as a bolt securing an annular collar onto a recessed threaded aperture on the face of a guitar. 
     The present invention of an electric guitar string tension device  30  contemplates a variety of device constructions including a retention bar  32  to rest on the guitar strings  16 , two support arms  34  at each end of the retention bar  32 , two pivotal attachment collars  36  on the other end of the support arms  34  and two connection bolts  38  to affix the attachment collars  36  to the guitar  10 . 
     The component in contact with the guitar strings  16  is the retention bar  32 . The retention bar  32  is held rotatably in place against the strings  16  by two support arms  34 . In a preferred embodiment, the retention bar  32  is tubular and the support arms  34  are rods. 
     The retention bar  32  should be slightly longer than the distance between the first string on the guitar  10  and the last string as measured perpendicular to the length of the strings  16  near the bridge of the guitar  12 . The inside diameter of the retention bar  32  should be slightly greater than the outside diameter of the support arms  34  to allow free rotational movement of the retention bar  32  yet close enough to be secure and not allow excessive movement. 
     The retention bar  32  may be constructed from a variety of materials known to one skilled in the art that provides sufficient strength and rigidity to prohibit excessive bending or flexing that may interfere with the operation of the string tension device  30 . For example, the retention bar  32  may be constructed of metal, polymer plastic or high-density polymer. A preferred material is metal tubing. 
     The support arms  34  may be constructed from solid rod material or hollow tubing material from a variety of materials known to one skilled in the art that provides sufficient strength and rigidity to prohibit excessive bending or flexing that may interfere with the operation of the string tension device  30 . Preferably, the support arms  34  are constructed of metal rods. Each support arm  34  is bent at two locations resulting in two legs, one long leg and one short leg. The longer legs of the support arms  34  are bent inward relative to the retention bar  32  at approximately 90 degrees and the shorter legs are bent outward relative to the retention bar  32  at approximately 90 degrees in accordance with  FIG. 4 . 
     The outside diameters of the support arm  34  rods are slightly less than the inside diameter of the tubular retention bar  32 . The longer legs of the support arms  34  are inserted into each end of the retention bar  32  during assembly. The lengths of the longer legs of the support arms  34  should be sufficient to provide strength to the assembled components yet not longer than approximately one half the length of the retention bar  32 . The distance is known by one skilled in the art to be related to the distance between the two bolts or apertures  14  that served to hold the tailpiece in place before the tailpiece was removed to accommodate the string tension device  30 . 
     The length of the support arms  34  between the two legs is determined by the amount of desired deflection of and tension on the strings  16 . One skilled in the art could determine a desired length based on the desired angle of the strings  16  relative to the bridge  12 . Such angle is critical to the invention as the greater the angle or the greater the tension, the more likely the strings  16  will remain on the bridge  12  as the guitar  10  is played. 
     One skilled in the art would recognize that the angle could also be adjusted by addition or removal of spacers under the annular collars  36 . Preferred spacers would be annular washers. 
     The short legs of the support arms  34  are attached to the annular collars  36 , each of which contain a recessed aperture. During assembly of the guitar string retention device  30 , the shorter legs of the support arms  34  are inserted into the recessed apertures which are mounted with the apertures facing each other. The inside diameter of the recessed apertures of the annular collars  36  is slightly larger than the outside diameter of the rods used for the support arms  34  to allow for free movement of the support arms  34 , yet close enough in diameter for the components to be securely held in place. 
     The annular collars  36  may be constructed from a variety of materials known to one skilled in the art that provides sufficient strength and ease of machining. For example, the annular collars  36  may be constructed of metal, polymer plastic or high-density polymer. 
     One skilled in the art would recognize that the inside diameter of the annular collars  36  should be slightly larger than the diameter of the affixing means such as connection bolts  38 . There should be a tight fit to prevent any movement of the annular collars  36  once assembled. The outside diameter and height of the annular collars  36  should be sufficient to provide sufficient depth for the recessed apertures of the annular collars  36  to accommodate the short legs of the support arms  34 . 
     An affixing means is necessary to attach the string tension device  30  to the electrical guitar  10 . One skilled in the art would recognize that the optimal attachment method would utilize the same connection system that was used to affix the tailpiece to the guitar  10 . Because the tailpiece is replaced by the vibrato unit  20 , the string tension device  30  could easily adapt to the former connection. In one embodiment, the attachment means would be connection bolts  38  that match the thread pattern of the former tailpiece connection  14 . 
     In another embodiment of the invention, the retention bar  32  and support arms  34  are constructed as one piece. In this configuration, the components could be cast or machined from metal. 
     Another aspect of the invention is the mounting means of the vibrato unit  20 . In one construction, a mounting bracket  40  may be used to affix the vibrato unit  20  to the electric guitar  10 . In one embodiment, the mounting bracket  40  may be a L shaped configuration that mounts at the bottom tail bolt  18  of the electric guitar  10  in accordance with  FIG. 2 . The face of the connection bracket  40  may allow a multiplicity of apertures that match the mounting bolt pattern on the vibrato unit  20 . An aperture located in the center of the connection bracket  40  may allow the tail bolt  18  to affix and secure the connection bracket  40 . Bolts extending outwardly from the connection bracket may be utilized to mount the vibrato unit  20 . The use of acorn nuts would provide a aesthetic installation. In another embodiment, screws may be used to affix the vibrato unit  20  to the guitar  10 . 
     In yet another embodiment, a kit for installing a vibrato unit  20  may include the spring tension device  30 , a connector bracket  40  custom fitted for specific vibrato units. connection bolts  38 , assembly screws or bolts and acorn nuts.