Patent Document

BACKGROUND OF THE INVENTION 
   This invention relates to tremolo devices such as those found on Stratocaster® style guitars and are disclosed in U.S. Pat. No. 2,741,146 issued to C. L. Fender on Apr. 10, 1956. The operation and shortcomings of this design were discussed in U.S. Pat. No. 6,943,284 issued to E. W. Didan on Apr. 14, 2005, and are reproduced here. Some reference numbers have been changed where they refer to the present invention. 
   “The bridge plate of the tremolo device is situated to pivot on an axis transverse to the direction of the strings. Bridge saddles located on the bridge plate engage the strings to create the intended change in string tension when the player moves the tremolo actuating arm. A counter spring is employed to oppose and counteract the pull of the strings on the bridge plate. 
   “A problem attendant to the use of such known tremolo devices arises with the breakage of a string. Because the tension of the strings is balanced by the above mentioned counter spring, loss of the force on one or more strings allows the counter spring to displace the bridge plate. This increases the tension on the remaining strings, causing them to go sharp. Thus, the instrument becomes unplayable. 
   “A second problem attendant to the use of such known tremolo devices arises when tuning. Because the tension of the strings is balanced by the above-mentioned counter-spring, change in force of the string being tuned causes the displacement of the bridge plate. This changes the tension on the remaining strings, causing them to go out of tune. In theory, an instrument with such a bridge can&#39;t be tuned. In practice, tuning may only be achieved by repeatedly tuning each successive string until converging on an acceptable tuning of all strings. Thus, the instrument is far more difficult to tune than one with an unmoveable or stabilized bridge. 
   “Referring now to the drawings in detail, wherein like reference numerals indicate like elements, there is seen in  FIG. 1  a guitar designated generally by the reference numeral  1 . As is conventional, the guitar  1  consists of a body  2  having a sounding board or face  8 . Attached to the body  2  is a neck  3 , having a nut  4  and means  5  for a retaining and adjusting the pitch of strings  6 . 
   “A tremolo device, designated generally by the reference numeral  9 , is secured to the face  8 , and secures the bridge end of the strings  6 . Referring now to  FIG. 2 , the tremolo device  9  includes a bridge plate  10 . 
   “Anchor screws  14  secured to the body  2  provide pivot points for the bridge plate  10 . In this regard, referring to  FIG. 6  the bridge plate  10  is provided with holes  24 , adapted to engage the anchor screws  14 . The anchor screws  14  provide a hinge for the bridge plate  10  relative to the face  8 . 
   “Referring now to  FIG. 7 , associated with the bridge plate  10  is an inertia block  11 , which projects downwardly from the bridge plate  10  and extends into a recess  31  in the body  2  of the guitar  1 . The strings  6  are secured by an inertia block  11 . 
   “A tremolo actuating arm  16  is secured to the bridge plate  10 . Also secured to the bridge plate  10  are bridge saddles  13 , which engage the strings  6 . Bridge saddles  13  have intonation screws  12  and elevation screws  15  to govern the length and height of each string respectively. 
   “It will now be seen that movement of the actuating arm  16  causes the bridge plate  10  to pivot relative to the anchor screws  14  and face  8 . The bridge  9  causes such movement to vary the tension of all of the strings  6  to produce the desired tremolo effect. 
   “A counter-spring  28  is provided within recess  31  and coupled in tension to the body  2  and inertia block  11 . Means  29  is provided to couple one end of the counter-spring  28  to an anchor screw  30 , associated with the body  2 . 
   “The foregoing structure is conventional and is found in the prior art, depicted in FIGS.  2  and  7 .” 
   BRIEF SUMMARY OF THE INVENTION 
   Virtually all Stratocaster.®. style guitars are manufactured with the tremolo device as described above. Many players do not use this device in their playing but are forced to deal with the shortcomings of the design as noted above. The present invention provides a solution to these problems by replacing the metal tremolo block, springs, claw, screws, and actuating arm with a machined hardwood block. The purpose of the block is to completely fill the vertical tremolo cavity and convert the guitar to a hardtail configuration. 
   The present invention clamps the bridge plate firmly to the body of the guitar, thus eliminating intonation and tuning problems associated with a counterbalanced floating bridge. This clamping is accomplished by a notch on the top rear portion of the present invention interfacing with a routered lip on the upper rear section of the tremolo cavity. As the bridge plate is screwed into the present invention, the routered lip on the rear section of the tremolo cavity is clamped between the bottom of the bridge plate and the notch described above. This clamping action allows any vibration of the bridge plate to be transmitted to the upper body of the guitar for increased resonance. 
   The present invention has six string holes drilled at an angle of 15 degrees from front to back so that the pull of the strings pulls the back of the block against the rear wall of the tremolo cavity. Any resonance of the bridge plate that is carried through the block is transmitted to the lower body of the guitar and acts in conjunction with the resonance provided by the top of the invention as discussed in [0014] above. 
   The present invention reduces the possibility of string breakage by having the strings enter the block at an angle of 75 degrees rather than the normal 90 degrees as would be the case with the tremolo bridge block. 
   The present invention does not require any cutting or drilling to the exterior of the guitar body. It is inserted from the rear of the guitar up into the tremolo cavity and is secured by three one-inch long #6 wood screws using the original bridge plate. The installation is readily reversible if desired. 
   In addition to the benefits noted above, by replacing the tremolo components below the bridge plate and the actuating arm the weight of the guitar is reduced by 10-15%. This is significant for anyone playing the guitar while standing for extended periods of time. 

   
     DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     There is seen in the drawings a form of the present invention which is presently preferred (and which constitutes the best mode contemplated for carrying the invention into effect), but it should be understood that the invention is not limited to the precise arrangement or materials shown. 
       FIG. 1  is a pictorial view of a guitar utilizing the present invention. 
       FIG. 2  is an enlarged perspective view of a tremolo device. 
       FIG. 3  is a top non-perspective view of the present invention. 
       FIG. 4  is a view of  FIG. 3  rotated 90 degrees clockwise to show the side view. 
       FIG. 5  is a view of  FIG. 3  rotated 180 degrees clockwise to show the bottom view. 
       FIG. 6  is an exploded perspective view showing the assembly of the present invention with the original bridge plate. 
       FIG. 7  is a partial cross-sectional view along sight-line  7  in  FIG. 1  showing a tremolo device in an operative condition. 
       FIG. 8  is a view similar to  FIG. 7 , taken along the line  7 - 7  in  FIG. 1  showing the present invention in its operative state. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   If a player does not use the tremolo when playing, a method of removing the counterbalancing feature of the tremolo bridge is desirable. Referring to  FIGS. 3 through 8 , a preferred method of accomplishing this is presented. 
     FIG. 3  shows a top view  17  of the present invention, herein after referred to as “the block”, and is designed to fit snugly into the routed tremolo cavity of body  2 . As presented, it is machined from a piece of clear maple hardwood with the grain running longitudinally from top to bottom and completely fills the vertical portion of the tremolo cavity as shown in  FIG. 8  reference  31 , including the rounded sections. Maple was used as its tonal qualities are most compatible with the neck, which is usually constructed of maple. 
   Six one-eighth inch diameter holes  18  are drilled so that they align with holes  25  on the bridge plate  10 . Three three-sixteenth inch holes  19  are drilled so that they align with holes  26  in the bridge plate  10 . 
   A notch  20  is cut one-quarter inch deep and one-quarter inch wide on the right-hand side of the top face  17 . This notch must interface with the lip  32  on the body  2  as shown in  FIG. 8 . This lip must be routered so that it is parallel to the top surface  8  of the guitar  2 . See  FIGS. 7 and 8 . The top of the block  17  must be kept one-sixteenth of an inch below the top surface  8  of guitar  2  in order that a clamping action can occur when the base plate  10  is secured to the block  17  using screws  27 . This one-sixteenth of an inch gap will be removed as this clamping is preformed. 
     FIG. 4  shows  FIG. 3  rotated 90 degrees clockwise having a cross-section  21 . Six holes  18  are drilled at angle  33  of 15 degrees from front to back. This angle of 15 degrees is critical to the performance of the block. A smaller angle will not provide enough pressure on the back of the block against the rear of the tremolo cavity causing a loss of sustain. A larger angle produces too much pressure and causes sustain to be lost. The bottom of the block is also cut at a 15 degree angle  34  from front to back. Holes  18  are counterbored three-eighths of an inch at the bottom to accept industry-standard metal ferrules  22 . These ferrules are important in centering the string in the bore. If the strings touch the walls of the bore, sustain will be lost. 
     FIG. 5  is a view of  FIG. 3  rotated 180 degrees clockwise and shows the bottom of the block having a face  23 . Holes  18  are counterbored and metal ferrules  22  have been inserted. 
     FIG. 6  is an exploded perspective view showing the assembly of the block  17  with the original bridge plate  10 . The bridge plate  10  is first secured to face  8  of the body  2  using the original screws  14  through holes  24 . The block is then pressed into the tremolo cavity  31  of  FIG. 8  from the rear until notch  20  intercepts lip  32  of the guitar. At this point, face  17  of the block is one-sixteenth of an inch below the bottom of bridge plate  10 . 
   Screws  27  are then inserted through holes  26  in the bridge plate  10  and screwed down until the bridge plate  10  is flush with face  8  of body  2 , and face  17  of the block is flush with the underside of base plate  10 . 
     FIG. 7  shows a partial cross-section view of a typical tremolo bridge in its normal operating position as viewed at angle  7  in  FIG. 1  and has been described in the section “Background of the Invention.” 
     FIG. 8  is a modified version of  FIG. 7  showing the block in its installed position. The original tremolo block  11 , springs  28 , claw  29 , retaining screws  30 , and actuating arm  16  have all been removed. Lip  32  has been routered so that its face is parallel to face  8 . 
   Each of the six strings  6  are inserted through holes in the ferrules  22 , up through holes  18 , then through the bridge plate holes  25  and over saddles  13 . They are terminated at the tuners  5 . The other end of the strings  6  have a metal ball or nut that is retained in the ferrules  22 , allowing the strings to be tuned. 
   No drilling or cutting of the guitar body  2  exterior is required to use the block and the guitar can easily be returned to its original setup if desired. 
   The present invention provides a means of overcoming the instability problems associated with a counterbalanced tremolo bridge and represents a viable option for players who do not use a tremolo. They also have the benefit of increased sustain provided by the interaction of the clamping action on lip  32  and the pressure provided to the lower portion of the block by the 15 degree string offset  18 . 
   The present invention may be used in other forms without departing from its essential attributes. Reference should be made to the claims rather than the above specification in determining the scope of the present invention.

Technology Category: g