Patent Publication Number: US-7718873-B1

Title: Stringed instrument vibrato device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. Ser. No. 11/749,719, filed on May 16, 2007, now U.S. Pat. No. 7,479,592, which is hereby incorporated herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT 
     Not Applicable. 
     NOTICE OF COPYRIGHTS AND TRADE DRESS 
     A portion of the disclosure of this patent document contains material which is subject to copyright protection. This patent document may show and/or describe matter which is or may become trade dress of the owner. The copyright and trade dress owner has no objection to the facsimile reproduction by any one of the patent disclosure as it appears in the Patent and Trademark Office patent files or records, but otherwise reserves all copyright and trade dress rights whatsoever. 
     FIELD OF THE INVENTION 
     This invention relates to musical instruments, and more particularly to a novel vibrato device for a stringed instrument. 
     DISCUSSION OF RELATED ART 
     Vibrato devices for guitars and other stringed instruments have been in use for many years for the special effect of bending the pitch of a note either higher or lower. Herein the term guitar typically refers to six-stringed guitars, but could mean any stringed instrument with any number of strings. The typical design used on guitars comprises a pivoting base plate located at the rear of the instrument, one or more string attachment devices mounted on top of the plate and an attached lever that, when moved, produces the is vibrato effect. Typically, two or three springs are attached at one end to the bottom of the plate to offset the tension of the strings, the strings being anchored to the instrument at their other ends. 
     Two basic types of vibratos exist: single directional, which can only change the pitch in one direction—usually higher, and two directional, which can either raise or lower the pitch at the musician&#39;s discretion. 
     The single directional vibrato is historically much older. It is fairly simple in design due to its limited abilities, relatively easy to tune and operate and is of no concern here. 
     The two directional device, often referred to as “full floating” vibrato, is more versatile to the musician and far more complex in design. Although these units are very popular, mostly among rock guitarists, every device on the market today has the same flaw—the inability to let the user tune the instrument quickly. 
     A non-vibrato, or solid-bridge guitar, such as the standard acoustic can be tuned by the average user in 1-2 minutes from a completely out of tune but “strings still attached” position. String replacement on a solid bridge guitar can easily be done by removing all six strings simultaneously, reattaching the six new strings and tuning them one at a time, usually in order from the lowest pitch string to the highest. Tuning each string only once results in the guitar being properly tuned when the series is finished. A single directional vibrato guitar may be tuned in substantially the same amount of time. 
     A full floating vibrato unit, however, will take the average user hours if not days to tune from a completely detuned condition, and many users find it beyond their ability entirely. The procedure involves far more than string pitch, becoming a delicate balancing act between the strings, the base plate, and springs located inside the body of the guitar. The procedure is so tedious that it is common to take the guitar to an experienced technician for a “set-up” requiring both time and money whenever new strings are required. 
     String replacement instructions included with the purchase of a new full floating guitar instruct the user to remove one string at a time, re-attach a new string, and re-tune the entire guitar before removing the next string. The process is then repeated five more times, once for each additional string. Even though this is far more tedious tuning than a solid bridge or single direction vibrato, the average user is capable of tuning his own guitar if that was the entire process. 
     However, the very nature of a full floating device forces the user to also level the “floating” base plate as well as tune the strings. Each time a string it tightened, the rear of the pivoting base plate rises. Each time the rear of the base plate rises, the tension of all other attached strings is lessened, dropping each in pitch. Tightening one string raises the rear of the base plate and in turn loosens all other strings. So in essence, raising the pitch of one string lowers the pitch of all other strings. Further, the tightening or loosening of the strings by use of the device stretches strings over time, loosening and detuning them. Common equipment on full floating guitars include tuning knobs and string locks at both ends of the guitar to help with the stretching problem, but the process is still too is cumbersome for many guitarists. 
     The public has found the problem so annoying that numerous devices are presently available on the market to try to help the average user tune a guitar without a technician&#39;s help. Several examples of such devices are taught in US Patent Applications and Patents 2004/0051925 to Smart on Mar. 18, 2004; 2004/0083875 to Burton on May 6, 2004; U.S. Pat. No. 6,812,389 to Trooien on Nov. 2, 2004; U.S. Pat. No. 6,919,501 to Burton on Jul. 19, 2005; and 2006/0005687 to Minakuchi on Jan. 12, 2006. Some of these devices lock the base plate from “floating” until the strings are tuned and the lock is removed, at which time the base plate moves anyway. Others lock the base plate permanently, deactivating the vibrato. While the guitar is then tunable, it behaves as nothing more than a solid bridge guitar, unsuitable for the serious enthusiast who wishes to have a vibrato effect as a playing option. Indeed, many guitarists have the device removed completely, opting for a solid bridge, to avoid the tuning problem altogether. 
     Further, if a string breaks while playing a full floating guitar, the guitarist is immediately thrown out of tune relative to other band members. Since the strings and springs are thrown out of balance with one less string pulling the plate upward, the springs take up the slack by pulling the plate downward, raising the pitch of the other five strings. Such an incident during a live performance can be disastrous if a replacement string and/or guitar is unavailable. US Patent Application 2005/0076766 to Didan on Apr. 14, 2005, attempts to address this problem. 
     U.S. Pat. No. 6,384,311 to Cota on May 7, 2002, shows a bass guitar with four separate vibrato units, one for each string. However, there is no way to vibrato all four strings together short of pushing on all four arms simultaneously. 
     US Patent Application 2003/0183062 to Schryer on Oct. 2, 2003, uses wheels that are notched like teeth on a sprocket, and each sprocketed wheel is locked inside a large cylindrical encasement. As such, there is no freedom of movement between strings once locked in place. 
     In my previous application, I successfully accomplished a vibrato device that allows for independent tuning of each string without substantially affecting the tuning of other strings. My prior device allows for quickly tuning all strings on the instrument, while still providing for an effective two-directional vibrato effect. Yet my prior device allows for greater changes upward in pitch than downward in pitch when the vibrato handle is actuated. As such, there is still a need for a vibrato device that allows for a generally equal number of steps in pitch both upward and downward when actuating the vibrato handle, while still retaining the benefits of my previous device. The present invention accomplishes these objectives. 
     SUMMARY OF THE INVENTION 
     The present device is a vibrato device for an instrument, such as a guitar, that has at least one string. The vibrato device includes a base plate with a pivot means formed proximately to a forward side thereof. A plurality of string attachment means are each fixed to the base plate and independently pivotable about an axis that is substantially parallel to, above, and to the rear of the forward side of the base plate. Each string attachment means is fixed to one string of the instrument and includes a string biasing means that keeps the string in tension. Each string biasing means generally balances the string around the pivot means. A vibrato handle is fixed to the base plate and, when moved, causes the base plate to pivot around the pivot means. 
     In use, with each string of the instrument fixed to one of the string attachment means, each string is tunable against the string biasing means independently of any other string. The base plate is biased thereby towards the pivot means along the longitudinal axis of the strings, whereby the vibrato handle may be moved to cause the base plate to pivot around the pivot means to cause the effective pitch of each string to be changed thereby. The base plate pivots on the pivot means while being prevented from lateral or elevational movement thereon. 
     In a simple embodiment of the invention, each string attachment means is an elongated string block having a forward end and an aperture therein for receiving one of the strings. The string block further includes proximate a rear end thereof a pivot aperture therein for pivoting around a pivot pin that is fixed with the base plate. The longitudinal axis of the pivot aperture is substantially perpendicular to the longitudinal axis of the string aperture. The axis of the pivot pin may be elevated above, or below, the base plate by fixing the is pivot pin to the base plate through a pair of raised, or lowered, pivot pin tabs. 
     A bridge is selectively fixable with the base plate. Each string attachment means holds one of the strings of the instrument against the bridge, which may include at least one roller for contacting each string. In one embodiment of the invention, each elongated string block further includes a second roller for contacting one of the strings. Further, the bridge may include a plurality of independent bridge elements, each of which is independently fixable to the base plate, and each being offset from adjacent bridge elements if desired. In one embodiment of the invention, each elongated string block is formed integrally with one bridge element, wherein each string block includes its own pivot pin. 
     The present invention is a vibrato device that allows for independent tuning of each string without substantially affecting the tuning of other strings. The present device allows for quickly tuning all strings on the instrument, while still providing for an effective two-directional vibrato effect, allowing for a generally equal number of steps in pitch both upward and downward when actuating the vibrato handle in either direction. Further, the present invention is easily added to existing guitars and other stringed instruments. Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial top plan view of my prior art invention as installed in a guitar; 
         FIG. 2  is an exploded view of my prior art invention; 
         FIG. 3  is a cross-sectional view of a string attachment means of my prior art invention, taken generally along lines  3 - 3  of  FIG. 2 ; 
         FIG. 4  is a partial perspective view of my prior art invention; 
         FIG. 5  is a partial top plan view of one embodiment of the invention; 
         FIG. 6  is an exploded view of the embodiment of  FIG. 5 ; 
         FIG. 7  is a partial perspective view of the embodiment of  FIG. 5 ; 
         FIG. 8  is a partial top plan view of another embodiment of the invention; 
         FIG. 9  is an exploded view of the embodiment of  FIG. 8 ; 
         FIG. 10  is an exploded perspective view of an elongated string block of the embodiment of  FIG. 8 ; 
         FIG. 11A  is a cross-sectional view of the elongated string block of the embodiment of  FIG. 8 , taken generally along lines  11 - 11  of  FIG. 8 , and illustrating a fine-tuning screw in a raised position; 
         FIG. 11B  is a cross-sectional view of the elongated string block of the embodiment of  FIG. 8 , taken generally along lines  11 - 11  of  FIG. 8 , and illustrating the fine-tuning screw in a lowered position; 
         FIG. 12  is a partial perspective view of the embodiment of  FIG. 8 ; 
         FIG. 13  is a partial top plan view of yet another embodiment of the invention; 
         FIG. 14  is an exploded view of the embodiment of  FIG. 13 ; and 
         FIG. 15  is a partial perspective view of the embodiment of  FIG. 13 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Illustrative embodiments of the invention are described below. The following explanation provides specific details for a thorough understanding of and enabling description for these embodiments. One skilled in the art will understand that the invention may be practiced without such details. In other instances, well-known structures and functions have not been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments. 
     Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural or singular number respectively. Additionally, the words “herein,” “above,” “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. When the claims use the word “or” in reference to a list of two or more items, that word covers all of the following interpretations of the word: any of the items in the list, all of the items in the list and any combination of the items in the list. 
       FIGS. 5-7  illustrate a simple embodiment of a vibrato device  10  for an instrument  20  that has a plurality of strings  30 . Each string preferably includes a string stop  33  at an end thereof. The vibrato device  10  includes a base plate  40  that has a top surface  48 , a bottom surface  42 , and at least one peripheral edge  45  connecting the top surface  48  with the bottom surface  42 . A pivot means  50  is formed proximately to a forward side  41  of the at least one peripheral edge  45 . Preferably the pivot means  50  includes two tapered notches  90  in the forward side  41  of the peripheral edge  45  and two pivot bolts  100 . Each pivot bolt  100  is fixed at one end  102  to the instrument  20  and has at a second end  108  a tapered waist  109  for engaging one of the tapered notches  90  ( FIGS. 6 and 7 ). 
     A plurality of string attachment means  60  are each fixed to the base plate  40  and independently pivotable about an axis l 1  that is substantially parallel to and to the rear of, the forward side  41  of the peripheral edge  45 . Each string attachment means  60  is fixed to one string  30  of the instrument  20  and includes a string biasing means  70  that keeps the string  30  in tension at the string attachment means  60 . Each string biasing means  70  generally balances the string  30  around the pivot means  50 . A vibrato handle  80  is fixed to the base plate  40  and, when moved, causes the base plate  40  to pivot around the pivot means  50 . 
     In use, with each string  30  of the instrument  20  fixed to one of the string attachment means  60 , each string is tunable against the string biasing means  70  independently of any other string  30 . The base plate  40  is biased thereby towards the pivot means  50  along the longitudinal axis of the strings  30 , whereby the vibrato handle  80  may be moved to cause the base plate  40  to pivot around the pivot means  50  to cause the effective pitch of each string  30  to be changed thereby. The base plate  40  pivots on the pivot bolts  100  at the notches  90  therein while being prevented from lateral or elevational movement thereon. 
     In the simple embodiment of the invention, each string attachment means  60  is an elongated string block  110  having a forward end  112  and an aperture  120  therein for receiving one of the strings  30  of the instrument  20 . The longitudinal axis of the aperture  120  is generally co-aligned with the longitudinal axis of the string  30 . The string block  110  further includes proximate a rear end  118  thereof a pivot aperture  130  therein for pivoting around a pivot pin  140  that is fixed with the base plate  40 . The longitudinal axis of the pivot aperture is substantially perpendicular to the longitudinal axis of the string aperture  120 . The axis l 1  may be offset above ( FIG. 6 ) or below (not shown) the base plate  40  by fixing the pivot pin  140  to the base plate  40  through a pair of pivot pin tabs  220  of the base plate  40 . 
     The string block  110  further includes a spring attachment means  150  fixed at a bottom side thereof. In one embodiment each spring attachment means  150  is a spring attachment aperture  160  traversing the bottom side  116  of each string block  110  and is adapted to capture one of the string biasing means  70  therein. Each string biasing means  70  may be, for example, a coil spring  170  having one end  172  fixed to one of the spring attachment means  150  and a second end  178  fixed to a spring attachment rod  180  that is fixed with the instrument  20  with a spring attachment rod mounting means  190  ( FIG. 6 ), such as a generally U-shaped bracket that includes at least one instrument mounting bolt  200  that is attachable to the instrument  20  through a bolt aperture  210  formed in a forward end of the bracket. 
     A global tension adjustment means  230  may include a pair of threaded apertures  240  fixed to the spring attachment rod mounting means  190 , each having a threaded adjustment screw  250  rotationally engaged therewith and each having a screw foot  255  is fixed thereto. As such, the screw foot  255  of each threaded adjustment screw  250  presses against the instrument  20  when mounted therein to cause the spring attachment rod mounting means  190  to pivot about each instrument mounting bolt  200  for adjusting the tension in each of the coil springs  170  ( FIG. 7 ). 
     A bridge  260  is selectively fixable with the top surface  48  of the base plate  40 . Each string attachment means  60  holds one of the strings  30  of the instrument  20  against the bridge  260 . The bridge  260  may include at least one roller  270  for contacting each string  30  of the instrument  20 , preferably at a bottom side  32  thereof. In one embodiment of the invention, each elongated string block  110  further includes a second roller  280  pivotally fixed between the aperture  120  of the forward end  112  thereof, and each second roller  280  contacts one of the strings  30  of the instrument  20  on a top side  38  thereof ( FIGS. 8-12 ). Further, the bridge  260  may include a plurality of bridge elements  262 , each of which is independently fixable to the base plate  40 , and each being offset from adjacent bridge elements  262  if desired ( FIG. 9 ). 
       FIGS. 9-12  illustrate an embodiment wherein each elongated string block  110  further includes a threaded string locking bolt  290  for receiving along a hollow longitudinal bore  295  therein one of the strings  30  of the instrument  20 . The string locking bolt  290  is engaged with a threaded aperture  305  in a pivot block  300  that pivots around the pivot pin  140  and is pivotally fixed within the string block  110 . A threaded fine-tuning screw  310  traversely mounted in the string block  110  is adapted to press against the locking bolt  290  and pivot the pivot block  300  to change the tension on the string  30 . 
     Each pivot block  300  may further include a string lock  320  pivotally fastened thereto. In such an embodiment the string locking bolt  290  is adjustable to press the string lock  320  against the string  30  to lock the string  30  longitudinally in place with respect to the pivot block  300 . 
     In one embodiment, illustrated in  FIGS. 13-15 , each elongated string block  110  is formed integrally with one bridge element  262 , wherein each string block  110  includes its own pivot pin  140 . As such, only as many elongated string blocks  110  need to be included as there are strings  30  on the instrument  20 , and such string blocks  110  may be easily individually replaced if damaged, for example. 
     While a particular form of the invention has been illustrated and described, it will be apparent that various modifications can be made without departing from the spirit and scope of the invention. For example, the particular shape of each elongated string block and the base plate may be varied from those illustrated. Further, while each string block  110  of the present invention has been illustrated on a mechanical pivot pin  140 , an alternate form of the invention instead includes a resilient rubber block (not shown) fixed between each string block  110  and the base plate  40 . As such, a resilient rubber block acts as the string biasing means  70 . Accordingly, it is not intended that the invention be limited, except as by the appended claims. 
     The teachings provided herein can be applied to other systems, not necessarily the system described herein. The elements and acts of the various embodiments described above can be combined to provide further embodiments. All of the above patents and applications and other references, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the invention. 
     These and other changes can be made to the invention in light of the above Detailed Description. While the above description details certain embodiments of the invention and describes the best mode contemplated, no matter how detailed the above appears in text, the invention can be practiced in many ways. Details of the system may vary considerably in its implementation details, while still being encompassed by the invention disclosed herein. 
     Particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the invention. 
     The above detailed description of the embodiments of the invention is not intended to be exhaustive or to limit the invention to the precise form disclosed above or to the particular field of usage mentioned in this disclosure. While specific embodiments of, and examples for, the invention are described above for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize. Also, the teachings of the invention provided herein can be applied to other systems, not necessarily the system described above. The elements and acts of the various embodiments described above can be combined to provide further embodiments. 
     All of the above patents and applications and other references, including any that may be listed in accompanying filing papers, are incorporated herein by reference. Aspects of the invention can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the invention. 
     Changes can be made to the invention in light of the above “Detailed Description.” While the above description details certain embodiments of the invention and describes the best mode contemplated, no matter how detailed the above appears in text, the invention can be practiced in many ways. Therefore, implementation details may vary considerably while still being encompassed by the invention disclosed herein. As noted above, particular terminology used when describing certain features or aspects of the invention should not be taken to imply that the terminology is being redefined herein to be restricted to any specific characteristics, features, or aspects of the invention with which that terminology is associated. 
     In general, the terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification, unless the above Detailed Description section explicitly defines such terms. Accordingly, the actual scope of the invention encompasses not only the disclosed embodiments, but also all equivalent ways of practicing or implementing the invention under the claims. 
     While certain aspects of the invention are presented below in certain claim forms, the inventor contemplates the various aspects of the invention in any number of claim forms. Accordingly, the inventor reserves the right to add additional claims after filing the application to pursue such additional claim forms for other aspects of the invention.