Abstract:
A locking device for an electric guitar with a tremolo base plate prevents pivotal movement of the tremolo base plate. The locking device has a slide plate with a receptive slot for slidable reception of a cooperative key. The key contains a body for initiation of longitudinal motion within the slide plate slot and has an adjustable engagement member which is alignable for contact with a rear edge of the tremolo base plate.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    The present invention relates generally to electric guitars. In particular, the present invention relates to a locking system for a floating bridge on an electric guitar.  
           [0002]    Electric guitars usually include a body, a neck, and a head, with strings extending from tuning posts connected to the head down to a bridge which is attached to the body of the guitar. Electric guitars are often made or retrofitted with mechanisms for changing the tension on one or more of the strings so as to vary the pitch. One mechanism used for varying the pitch is often referred to as a tremolo, or a floating bridge. The use of such a mechanism changes the tension on all of the strings together, resulting in a vibrato or tremolo effect. This is a result of reducing the tension or increasing the tension on the strings in what is known as a “choking” effect, or “note bending” and/or “detuning”.  
           [0003]    Because of varying tensions on the strings caused by the use of the tremolo, the strings may slip with respect to the tuning posts, with the result being that one or more of the strings will go out of tune. To prevent the strings from going out of tune, an electric guitar with a floating bridge may incorporate a string locking device between the neck and the head. The string lock mechanism is a clamp used to clamp the strings in a fixed position after the guitar has been tuned. Tuning knobs are initially adjusted on the head to tune the guitar, and then the string lock is secured and the guitar may be played and the vibrato used without causing the strings to go out of tune. As a result of engaging the string lock, the tuning knob for each string is made become unavailable for use to adjust the pitch of its respective strings.  
           [0004]    Ordinary use during the course of playing may cause strings to go out of tune due to various factors. As a result of this, many guitars include a method for tuning the guitar while the string lock is engaged. Such mechanisms are fine tuning mechanisms usually located on the bridge of the guitar, and serve to keep the guitar in tune unless a string breaks. A broken string may require the re-tuning of all the strings, since the tension on the other strings will change when the load born by a tremolo bridge&#39;s counter springs is compensated by the remaining strings (which is one less string than before the break). Replacing the broken string requires removal of the string locking device and re-tuning the instrument. Such an operation is time consuming. One way to reduce the amount of the time needed for re-tuning is to incorporate a bridge lock on the instrument to hold the bridge in place while replacing a broken string.  
           [0005]    When a musician plays a guitar with a tremolo, a song often contains sections that do and do not require the use of the tremolo. Absent a locking mechanism, the tremolo is always active on the guitar when playing such a song. Players must be careful when playing an instrument with the tremolo engaged as any pressure on the bridge of the guitar will result in the strings being tensioned or loosened, resulting in a change in the pitch for those strings.  
           [0006]    One solution to this problem is to employ a system whereby the player can somehow lock the floating tremolo bridge from movement relative to the guitar body. Locking the tremolo bridge prevents accidental motion of the tremolo bridge and provides a steadier tone when the strings are plucked, since there is no movement of the tremolo bridge. While tremolo locking systems are known, none provide a non-unintrusive, simple to mount and simple to manipulate locking system. Known locking systems may employ pivotal or rotation engagement of a locking device, which can be awkward for a musician to manipulate while simultaneously playing the guitar. In addition, many known locking systems may require more extensive modification of the guitar body than desired, and a resultant rather complicated installation procedure.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    In one embodiment, the present invention is a locking device for selectively preventing pivotal movement of a tremolo base plate toward and away from a guitar body. The tremolo base plate is of the type that is disposed under one end of a plurality of longitudinally extending guitar strings and has a laterally extending rear edge. The locking device comprises a slide plate attached to the guitar body adjacent the rear edge of the tremolo base plate, and a lock support slideably mounted on the slide plate. The lock support is moveable longitudinally on the slide plate between a first position spaced from the rear edge of the tremolo base plate and a second position engaged with the rear edge of the tremolo base plate. When the lock support is in its second position, the tremolo base plate is prevented from pivotal movement toward and away from the guitar body.  
           [0008]    In one embodiment, the present invention is an improvement in a guitar of the type having a tremolo base plate mounted to a guitar body of the guitar for pivotal movement toward and away from the guitar body in order to produce tremolo sounds and a locking device for selectively preventing such pivotal movement. The improvement comprises a locking device having a lower portion and an upper portion, with the lower portion being fixedly attached relative to a top surface of the guitar body rearwardly from the tremolo base plate, and the upper portion being mounted on the lower portion for slideable longitudinal movement relative to the lower portion between a first disengaged position spaced from the tremolo base plate and a second engaged position contacting the tremolo base plate.  
           [0009]    In one embodiment, the present invention is a method for selectively immobilizing a tremolo base plate from pivotal movement toward or away from a stringed instrument. The inventive method comprises: providing a slide plate affixed to the body of a stringed instrument, with a lock support slidably mounted on the slide plate, wherein the lock support has a tremolo plate engagement member moveably mounted thereon; selecting a locked position of the engagement member relative to the lock support; fixing the engagement member in the locked position; and longitudinally sliding the lock support along the slide plate until the engaging member contacts the tremolo base plate to fix it in position relative to the body of the stringed instrument. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The present invention will be further explained with reference to the drawing figures listed below, wherein like structures are referred to by like numerals throughout the several views.  
         [0011]    [0011]FIG. 1 is a isometric view of a guitar with a locking device mounted onto the guitar body, adjacent its tremolo bridge.  
         [0012]    [0012]FIG. 2 is an enlarged top view of the tremolo bridge and the locking device.  
         [0013]    [0013]FIG. 3 is a sectional view as taken along lines  3 - 3  in FIG. 2.  
         [0014]    [0014]FIG. 4 is an exploded view showing the components of the inventive locking device. 
     
    
       [0015]    While the above-identified drawing figures set forth one embodiment of the invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art which fall within the spirit and scope of the principles of this invention.  
       DETAILED DESCRIPTION  
       [0016]    [0016]FIG. 1 illustrates a typical electric guitar of the type having a body  2 , a neck  4 , a head  6 , a floating tremolo bridge  8  and a tremolo lever  10 . The head  6 , neck  4 , and body  2  are usually made of wood or some composite or polymer, while the tremolo bridge  8  and tremolo lever  10  are usually constructed of metal such as steel. A plurality of longitudinally extending strings  14  are stretched from the head  6  of the guitar  1  over the length of a neck  4  and attached to the tremolo bridge  8 . To create a tremolo sound effect, a player exerts pressure on the tremolo lever  10 , which moves the tremolo bridge  8  relative to the guitar body  2 . The movement of the tremolo bridge  8  changes the tension exerted on the strings  14 , resulting in a change in pitch when the strings  14  are played. Rapid back and forth or rocking movement of the tremolo lever  10  will produce a vibrato effect. The FIGS. illustrate a six string guitar, but this is only intended to represent a typical stringed instrument for application of the present invention, which will have applicability on any stringed instrument having a floating tremolo bridge.  
         [0017]    As seen in FIG. 1, a tremolo locking device  12  is mounted on the guitar body  2 , adjacent the tremolo bridge  8 . When activated, the locking device  12  stops all motion of the tremolo bridge  8  by holding the bridge in a stable position relative to the guitar body  2 . The lack of motion of the tremolo bridge  8  has two advantages. First, if one of the strings breaks, the rest of the strings are stabilized in position and may not require immediate re-turning. As a result, play of the guitar may continue (even absent one of the strings) and when that string is eventually replaced, the tuning operation is quicker, allowing a player to reduce downtime of the instrument. Second, the tremolo bridge  8  is held in a fixed position so there is no motion in the tremolo bridge  8 , and thus none in the strings  14 . This creates a steady tone as the strings  14  are played.  
         [0018]    [0018]FIGS. 2 and 3 are enlarged views of the tremolo bridge  8  and inventive locking device  12 . As illustrated in FIG. 2, the tension provided by a spring  20  under the tremolo bridge  8  exerts a force against the tension exerted by the strings  14  on the top of the tremolo bridge  8 . The spring  20  is attached to the guitar body  2  in a cavity  21  below the tremolo bridge  8 . In this exemplary form of a tremolo bridge  8 , the tremolo bridge  8  has a tremolo base plate  22  extending over the cavity  21 . The tremolo base plate  22  is pivotally connected at its front end  23  to a top surface  24  of the guitar body  2 , adjacent a forward end of the cavity  21 . A pair of pivot mounts  26  and  28  are fastened to the guitar body  2  and positioned against the front end  23  of the tremolo base plate  22 . The pivot mounts  26  and  28  are notched or tapered to provide lateral pivoting points for the front end  23  of the tremolo base plate  22 , which itself is tapered to a laterally extending sharp front edge in engagement with the pivoting points of the pivot mounts  26  and  28 . Unless the inventive locking device  12  is engaged, the tremolo base plate  22  is thus free to pivot relative to the guitar body  2  about the pivoting points  26  and  28 , in direction of arrows  29  (FIG. 3). In operation, the player moves the tremolo lever  10  attached to the tremolo base plate  22 . The resulting movement of the tremolo base plate  22  changes the pitch of the strings  14  by extending or shortening the length of the strings  14  as the player pushes down or pulls up on the tremolo lever  10  (relative to the guitar body  2 ).  
         [0019]    As illustrated by FIG. 3, the tremolo base plate  22  is held in a steady position if there is no pressure put onto the tremolo lever  10  due to the force exerted on the tremolo bridge  8  by the spring  20 . However, since the tremolo base plate  22  contains six strings  14  attached to it, if one string should break, the string tension counteracting the tension of the spring  20  changes and the tremolo base plate  22  will move (pivoting downwardly, or counterclockwise as viewed in FIG. 3). For this reason (among others), the locking device  12  is installed to provide a means for holding the tremolo base plate  22  steady when the guitar player so desires.  
         [0020]    The tremolo bridge  8  illustrated in FIGS.  1 - 3  is shown in simplified form for clarity. The tremolo base plate  22  has a laterally extending rear edge  30  thereon, as seen in FIGS. 2 and 3. It is typical for a tremolo bridge  8  to include a fine tuning adjustment apparatus for each string  14 . An exemplary fine tuning apparatus  32  is illustrated in phantom for string  14 A in FIG. 2, and may include an adjustment knob  34  for each string  14  extending rearwardly past the rear edge  30  of the tremolo base plate  22 . The fine tuning adjustment apparatus  32  is used to fine tune a string independently of other strings, without using a string tuning knob on the head  6  of the guitar  1 .  
         [0021]    The inventive locking device  12  is mounted onto the guitar body  2  adjacent the rear edge  30  of the tremolo base plate  22 . The locking device includes a slide plate  35  which is attached to the top surface  24  of the guitar body  2  using one or more screws  37  or similar fasteners. In the illustrated embodiment, two screws  37  are used to secure the slide plate  35 . The holes for the screws  37  in the slide plate  35  are countersunk to allow tapered screw heads to lie flush or below the surface of the slide plate  35 . The slide plate  35  is mounted near the rear edge  30  of the tremolo base plate  22  (just rearwardly of the cavity  21  in the guitar body  2 ). The slide plate  35  has a longitudinally extending keyway  39  thereon, as seen in FIG. 4, which defines a slide slot  40 . In the illustrated embodiment, the keyway  39  is shaped like an inverted “T”, but any suitable keyway shape will suffice. The locking device  12  includes a lock support  41  which has a key  43  (FIG. 4) shaped to mate with the shape of the keyway  39  in the slide plate  35 . This cooperative arrangement thus permits longitudinal movement of the lock support  41  relative to the slide plate  35  (and tremolo bridge  8 ).  
         [0022]    In the embodiment illustrated, the key  43  of the lock support  41  is shaped like an inverted “T” formed by horizontal wings  45 ,  45  and a vertical body  47 . A vertical upper member  49  extends from the vertical body  47  adjacent a forward end of the body  47 . From a rear end of the lock support  41 , a handle  51  extends rearwardly beyond the vertical body  47  and has a plate  53  attached thereto. The plate  53  is chamfered on its top corners to eliminate sharp corners that could injure a performer utilizing the locking device  12 . In the embodiment illustrated, the handle  51  angles vertically toward the rear, and then extends horizontally and rearwardly, perpendicular to the vertical upper member  49 . The plate  53  and handle  51  form a finger touch arm  55  for use in manual manipulation of the locking device  12  while playing the guitar  1 . While performing, the player may manually push or pull the finger touch arm  55 , thus moving the lock support  41  longitudinally relative to the slide plate  35  and tremolo bridge  8 .  
         [0023]    An engagement member  57  is movably mounted on the vertical upper member  49  of the lock support  41 . The engagement member  57  contains a threaded hole on a rear side thereof for reception of a set screw  59 . A vertical bore  61  extends through the engagement member  57  and is shaped to slidably receive the vertical upper member  49  of the lock support  41 . In the illustrated embodiment, the engagement member  57  is parallelopiped shaped. Two jaws  63  and  65  extend from the top and bottom of a front side of the engagement member  57 . The jaws  63  and  65  are mirrors of each other, and contain angled faces extending from outer surfaces toward inner surfaces. A portion of the front side of the engagement member  57 , between inner faces of the jaws  63  and  65 , extends laterally and is shaped for reception of the rear edge  30  of the tremolo base plate  22 . Thus, the front side of the engagement member  57  contains a c-shaped opening to allow for reception of the rear edge  30  of the tremolo base plate  22 . By using the set screw  59 , the engagement member  57  can be fixed in position anywhere along the height of the vertical upper member  49  of the lock support  41 , as indicated by arrows  67 . This allows the player to adjust the locking device  12  to fix the position of the tremolo bridge  8  in any position he or she desires relative to the guitar body  2 . The components of the locking device  12  are made of metal or some other suitably rigid material (i.e., polycarbonate).  
         [0024]    [0024]FIGS. 2 and 3 show the locking device  12  in two positions, relative to the tremolo bridge  8 : (1) spaced rearwardly and disengaged (in solid), and (2) moved forwardly and engaged (in phantom). The keyway and key are shaped so that the lock support  41  does not separate from the slide plate  35  at either end thereof. The lock support  41  is retained in its desired position relative to the slide plate  35  by friction, yet the lock support  41  is easily movable longitudinally by manual pressure on the touch arm  55  thereof (in direction of arrows  69  in FIG. 3) to either engage or disengage the engagement member  57  and the rear edge  30  of the tremolo base plate  22 . When the tremolo bridge  8  includes fine tuning adjustment apparatus (which may include adjustment knobs  34  (FIG. 2) extending rearwardly from the tremolo base plate  22 , the engagement member  57  is shaped and positioned to engage the tremolo base plate  22  without interfering with the fine tuning adjustment apparatus (or other devices mounted on the guitar  1 ). Preferably, the slide plate  35  is positioned so that when the locking device  12  is engaged, the engagement member  57  contacts the center of the rear edge  30  of the tremolo base plate  22 . However, it is possible to mount the locking device  12  elsewhere as long as the engagement member  57  is contacting the rear edge  30  of the tremolo bridge plate  22 .  
         [0025]    Since the engagement member  57  is adjustable, it is possible for a player to use the locking device  12  to aid in the tuning of the guitar  1 . This is accomplished by setting the set screw  59  in the engagement member  57  in a higher or lower position along the vertical upper member  49  of the lock support  41 . For example, by setting the engagement member  57  at the top end of the vertical upper member  49 , and locking the tremolo base plate  22  at this position, the tremolo bridge  8  will be pivoted upward, thus reducing the length and tension of the strings  14  and resulting in a flattened tone of all the strings  14 . To engage the tremolo base plate  22  in this position the player must exert some upward pressure on the tremolo arm  10  to draw the tremolo base plate  22  upwardly. The lock support  41  is then moved forwardly so that the engagement member  57  thereon engages the rear edge  30  of the tremolo base plate  22 .  
         [0026]    The locking device of the present invention, when engaged, stops motion of the tremolo bridge in both pivotal directions. Also, the present invention provides an easy to manipulate tool to assist in re-tuning a guitar when a string breaks by only requiring the tuning of a single string instead of all strings on the instrument. The invention overcomes the drawbacks present in prior art, and is a simple, inexpensive and easily accessible addition to an existing instrument. The present invention is easy to use while playing the instrument requiring, for example, only a single finger to selectively disable the tremolo bridge and create a fixed bridge.  
         [0027]    Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention. For instance, as noted above, the slot in the slide plate created by the keyway can be of numerous geometries so long as it allows for the reception and longitudinal sliding of a lock support key therein. As discussed above, friction alone may suffice to retain the lock support in a desired position relative to the slide plate, although other means for doing so can be provided, such as detent engagement therebetween or the use of one or more magnets operable to hold the lock support in place relative to the slide plate. Shapes for the lock support  41  and its components (e.g., the touch arm  55  and engagement member  57 ) other than those illustrated are contemplated, so long as the requisite functions are achieved.