Patent Abstract:
A locking and tuning stabilizing device for an electric guitar having a tremolo device includes a clamp screw and an adjustment screw to enable the player to lock the tremolo or to stabilizing the tuning of the strings by turning an appropriate, easily accessible knob projecting from the guitar. In a first embodiment, an axially movable pin is in contact with the tremolo device at one end and in contact with an adjustment screw disposed in the end of the guitar at the opposite end. In second and third embodiments, an anchor block is disposed within a cavity on the back of the guitar. A pin connects to the tremolo device and is axially slidable within the anchor block. Clamping the pin to a fixed position within the anchor block, by tightening a clamp screw disposed in the anchor block, functions to lock the tremolo device in place.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATION 
   This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/421,790, filed Oct. 29, 2002. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to electric guitars equipped with “floating bridge” tremolo devices. More specifically, the invention is a locking and tuning stabilizing device which modifies a Floyd Rose floating bridge tremolo device to permit the user to more easily lock the tremolo device, thereby stopping the tremolo effect, which stabilizes the tuning. With the present invention, locking the tremolo device can be performed quickly and easily by manually turning respective knobs that are located at conveniently accessible locations on the guitar, even when playing the guitar. 
   2. Description of Related Art 
   Tremolo devices used on stringed instruments, such as guitars, have been used for a long time. One of the original and still very popular solid-body electric guitars equipped with a tremolo device is the guitar built by the Fender Musical Instruments Corporation (Scottsdale, Ariz.), which dates back to the 1950&#39;s. However, more recently, this type of tremolo device has been replaced with a more widely used tremolo device called the “Floyd Rose” tremolo device, originally patented in 1979 by Floyd Rose in U.S. Pat. No. 4,171,661, discussed below. In both the original Fender and the original Rose versions, the tremolo devices are blocks that pivot on a fulcrum located on the front face of the guitar. On one side of the fulcrum, the tremolo block is fastened to the strings on the front face of the guitar; on the opposite side, the tremolo block is attached to springs that, in turn, are fastened to the guitar body in a cavity near the rear face. 
   U.S. Pat. No. 668,604, issued to Russell on Feb. 19, 1901, U.S. Pat. No. 1,747,650, issued to Sawyer on Feb. 18, 1930, and U.S. Pat. No. 1,755,019, issued to Parker, Jr. on Apr. 15, 1930, broadly teach stringed musical instruments that have tremolo effects created by bending the neck of the instrument back-and-forth relative to the body. 
   U.S. Pat. No. 4,171,661, issued to Rose on Oct. 23, 1979, teaches a guitar with a tremolo device in which the strings are intended to stay in tune when the tremolo device is not being used. 
   U.S. Pat. No. 4,285,262, issued to Scholz on Aug. 25, 1981, teaches a tremolo device in which all the strings can be re-tuned simultaneously. 
   U.S. Pat. No. 4,383,466, issued to Shibuya on May 17, 1983, teaches a tremolo device for an electric guitar in which the strings can be individually tuned. 
   U.S. Pat. No. 4,608,906, issued to Takabayashi on Sep. 2, 1986, teaches a guitar tremolo device having a tuning feature. 
   U.S. Pat. No. 4,656,916, issued to Gressett, Jr. on Apr. 14, 1987, teaches a modified tremolo device which tunes all the strings simultaneously using an adjustment screw extending from the device to the bottom of the guitar. 
   U.S. Pat. No. 4,882,967, issued to Rose on Nov. 28, 1989, teaches a tremolo device having a locking feature. 
   U.S. Pat. No. 5,311,804, issued to Wilkinson on Mar. 17, 1994, teaches a spring-loaded locking mechanism for a “floating bridge” tremolo device, such as for a Floyd Rose tremolo device. 
   U.S. Pat. No. 5,986,192, issued to Wingfield et al. on Nov. 16, 1999, teaches a locking device for tremolo devices on electric guitars. 
   There is a need in the art, however, for a convenient manner of locking or unlocking the tremolo device whenever desired, particularly by using easily accessible and rotatable knobs on the guitar body. 
   None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed. 
   SUMMARY OF THE INVENTION 
   The present invention is a locking device for a guitar equipped with a tremolo device, specifically of the type typically called the Floyd Rose tremolo block. The Floyd Rose tremolo block is used by electric guitar players to provide a tremolo effect by moving a tremolo arm towards and away from the body of the guitar while playing in order to vary the tension on the strings, the tremolo arm being connected directly to the tremolo block. The tremolo block includes a knife-edge that pivots back-and-forth with the movement of the tremolo arm on a fulcrum, e.g., a pair of spaced screws, which is fixed to the front face of the guitar. On one side of the fulcrum, the tremolo block is fastened to the lower ends of the strings on the front of the guitar. On the opposite side of the fulcrum, the tremolo block is fastened to a set of springs that are, in turn, fastened to the body of the guitar inside a cavity near the rear face of the guitar. 
   The locking and tuning stabilizing device of the present invention includes an elongated pin extending from the tremolo block, with a compression spring and an adjustment screw axially aligned with the pin, and a clamp screw aligned normal to the pin. When the clamp screw is in an unlocked position, the tremolo device operates as designed to alter tension on the guitar strings in response to movement of the tremolo arm. When the clamp screw is tightened to a locked position against the pin, the tremolo block is unable to pivot, thereby disabling the tremolo device. When the clamp screw is in the unlocked position, the adjustment screw may be moved axially to adjust the bias on the compression spring, which takes any “slack” out of the strings, thereby allowing the device to be as effective as possible. 
   The locking and tuning stabilizing device may be furnished as original equipment with the guitar, or may be installed as an aftermarket addition to a guitar having a tremolo device. 
   Accordingly, it is a principal object of the invention to provide a locking and tuning stabilizing device for a guitar equipped with a tremolo device for temporarily disabling the tremolo device. 
   It is another object of the invention to provide a locking and tuning stabilizing device for a guitar equipped with a tremolo device in which the locking device is easily operable by a single clamp screw. 
   It is a further object of the invention to provide a locking and tuning stabilizing device for a guitar equipped with a tremolo device having an adjustment screw for adjusting spring bias applied to the tremolo device for more effectively stabilizing the tuning of the guitar strings. 
   Still another object of the invention is to provide a locking and tuning stabilizing device for a guitar equipped with a tremolo device which may be installed as original equipment with the guitar, or as an aftermarket addition. 
   It is an object of the invention to provide improved elements and arrangements thereof in an apparatus for the purposes described which is inexpensive, dependable and fully effective in accomplishing its intended purposes. 
   These and other objects of the present invention will become readily apparent upon further review of the following specification and drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIGS. 1A and 1B  are front and rear plan views, respectively, of a guitar tremolo device modified to include the locking and tuning stabilizing device according to the first embodiment of the present invention. 
       FIG. 1C  is a section view along the lines  1 C— 1 C of FIG.  1 A. 
       FIG. 2  is a plan view of the first embodiment of the tremolo locking and tuning stabilizing device without the guitar structure. 
       FIG. 3A  shows a perspective view of the knife-edged pin bracket of the locking and tuning stabilizing device of the present invention. 
       FIG. 3B  is a section view along lines  3 B— 3 B of FIG.  3 A. 
       FIGS. 4A and 4B  show fragmented elevational views of the contact of the adjustable pin with the knife-edged bracket in the locking and tuning stabilizing device of the present invention. 
       FIG. 5  shows a perspective view of a guitar with the components of the locking and tuning stabilizing device of the present invention exploded. 
       FIG. 6  shows a plan view of a second embodiment of a guitar tremolo locking and tuning stabilizing device according to the present invention. 
       FIG. 7  is a section view along the lines  7 — 7  of FIG.  6 . 
       FIG. 8  shows a plan view of a third embodiment of a guitar tremolo locking and tuning stabilizing device according to the present invention. 
       FIG. 9  is a section view along the lines  9 — 9  of FIG.  8 . 
       FIG. 10  is an exploded view of a clamp screw of a guitar tremolo locking and tuning stabilizing device according to the present invention. 
       FIG. 11  is a section view similar to  FIG. 1C , showing rotation limiting hardware disposed on the clamp screw of a guitar tremolo locking and tuning stabilizing device according to the present invention. 
   

   Similar reference characters denote corresponding features consistently throughout the attached drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   The present invention is directed to a device for locking and stabilizing the tuning of a guitar equipped with a Floyd Rose “floating bridge” tremolo device in order to temporarily disable the tremolo device and to facilitate stabilizing the tuning of the guitar. In addition, the invention prevents the guitar from going out of tune when a guitar string is broken. 
     FIGS. 1A through 5  are directed to a first embodiment of the lock and tuning stabilizing device of the present invention.  FIGS. 1A and 1B  show a fragmented front view and a fragmented rear view of an electric guitar  100  including a first embodiment a locking and tuning stabilizing device for a Floyd Rose tremolo device. The locking and tuning stabilizing device of the present invention is particularly suitable for use with an electric guitar equipped with a Floyd Rose tremolo device. 
   The guitar  100  is conventional in construction, having a body with a front face and a rear face, a neck extending from the body, and a plurality of strings  172  extending from a tailpiece or bridge  180  up the neck to a nut (not shown) and pegs (not shown) for adjusting tension on the strings  172 . A plurality of knobs  120  on the front face of the guitar  100  are electrically connected between a transducer in the body and an amplifier for adjusting the quality of the amplified sound (bass, treble, etc.). As shown in  FIGS. 1B and 5 , the rear face of the body of the guitar may have a cover  190  providing access to a cavity  192  defined in the body which contains at least some of the components of the tremolo device. 
   The tremolo device, shown schematically in the drawings, is also conventional in construction. As seen in  FIGS. 1A-1C ,  2 , and  5 , the tremolo device includes an L-shaped tremolo block  150  having a first leg or plate  144  extending parallel to the body of the guitar  100 , and a second leg  146  extending into the cavity  192 . The first leg  144  terminates in a knife-edge  152  which pivots against the neck of one or more screws  154  attached to the front face of the guitar body. The second leg  146  has a plurality of bias springs  80  attached thereto at fitting  84  and disposed in the cavity  192  which extend between the second leg  146  of the tremolo block  150  and an L-shaped bracket  88  affixed to the wall of the cavity, e.g., by screws  90 . The bottom ends of the strings  172  are attached to the tremolo block  150  by fittings  156  which include fine adjustment screws  158 . A tremolo arm  110  is attached to the tremolo block  150  and extends from the front face of the guitar. 
   When the guitarist wishes to create a tremolo effect, movement of the arm  110  causes the knife-edge  152  to pivot against screw(s)  154 , raising or lowering tremolo block  150  against the bias of springs  80 , thereby altering tension on the strings  172  and creating a tremolo effect. The foregoing is conventional in a Floyd Rose tremolo device. 
   The present invention is a locking and tuning stabilizing device for temporarily locking the tremolo device to prevent its operation, and to provide means for stabilizing tuning of a guitar equipped with the tremolo device. In the first embodiment of the present invention, the guitar body is modified by drilling cylindrical bores into the body, a first bore  76  being perpendicular to and in communication with a second bore  78 . The first bore  76  extends from the end  102  of the guitar  100  opposite the neck and into the tremolo cavity  192 . The second bore  78  extends from the front face of the guitar into the first bore  76 . 
   The outer portion of the first bore  76  towards the end  102  of the body of the guitar  100  is threaded to receive an adjustment screw  30 . The inner portion of the first bore  76  extending between the adjustment screw  30  and the cavity  192  has an elongated, smooth-faced cylindrical sleeve  62  that is fixed essentially flush with the internal surface of the first bore  76  and held in place. An opening  64  is formed in the wall of sleeve  62 , and the opening  64  is placed in alignment with the second bore  78 . Inside the sleeve  62 , a pin  70  is movable axially. A compression spring  50  is disposed between the adjustment screw  30  and the pin  70 . 
   An inner L-shaped tremolo bracket  36 , and an outer, L-shaped tremolo bracket  32  which overlaps the inner bracket  36 , are fixed to the tremolo block  150 , e.g., by fasteners  86 . As shown in  FIGS. 3A and 3B , outer bracket  32  is an angle formed by two plates connected at right angles. A slot  34  is defined through one of the plates, bisecting the plate and extending partially into the second plate. The edges  42  of the bisected plate at the slot  34  are beveled. As shown in  FIG. 4B , the inner bracket has a recess or slot  38  defined therein which is aligned with the slot  34 . 
   The end of the pin  70  opposite spring  50  has a neck  72  defining a ball head  74  at the end of the pin  70 . As shown in  FIGS. 4A and 4B , the neck  72  of the pin  70  slides between the beveled edges  42  of the slot  34 , the head  74  of the pin being accommodated by the recess or slot  38  defined in inner bracket  36 , so that pin  70  is attached to tremolo block  150 , the block  150  being free to move in response to tremolo arm by the sliding movement of brackets  32  and  36  on the head  74  of pin  70 . 
   Second bore  78  may be threaded, or a threaded sleeve may be fixed in the second bore  78 , or the opening  64  in sleeve  62  may be internally threaded, to receive a clamp screw  40 . Clamp screw  40  is of sufficient length that it extends through opening  64  to clamp pin  70  against the opposing wall of sleeve  62  when in the locked position, thereby preventing axial movement of pin  70 . In the unlocked position, clamp screw  40  is withdrawn into second bore  78  just sufficiently to permit axial movement of pin  70 . 
   In operation, when the guitarist wishes to produce a tremolo effect, the clamp screw  40  on the front face of the guitar body is moved to the unlocked position. When the guitarist wishes to preclude the tremolo effect, the clamp screw  40  is moved to the locked position to preclude axial movement of pin  70 , thereby precluding rocking of tremolo block  150 . In the locked position, tuning stability is greatly increased. 
   Referring to  FIGS. 10 and 11 , the clamp screw  40  may include hardware to prevent the clamp screw  40  from being excessively tightened or backed too far out of the second bore  78 . A threaded flange  46  is pressed into the guitar body at the top of the second bore  78 . A pin  48  extends from the top surface of the threaded flange  46 . A semi-circular stop  44  is fastened to the clamp screw  40  so that, once the clamp screw  40  is properly positioned, the pin  48  and the semi-circular stop  44  prevent the clamp screw  40  from being turned more than a single partial turn. 
   A second embodiment of the locking and tuning stabilizing device, designated as  200  in the drawings, is shown in  FIGS. 6 and 7 . In this embodiment, no bores are made in the body of the guitar. The device  200  is entirely enclosed in the cavity  192  and accessed through a cover  296  in the rear face of the body of the guitar, similar to the cover  190  shown in FIG.  1 B. The tremolo device is again conventional in construction, and includes tremolo block  300 , tremolo arm  310 , knife-edge  320 , pivot screws  324 , strings  302 , and tremolo springs  210  connected to tremolo block  300  by fasteners  216 , and fixed to a bracket attached to the body by fasteners  212 , all of which are similar in construction and operation to the tremolo device discussed above. The tremolo block  300  has a first leg  204  extending parallel to the body of the guitar  100 , and a second leg  206  extending into the cavity  192 . 
   In this embodiment, the locking and tuning stabilizing device includes an L-shaped bracket  250  fixed to the second leg  206  of the tremolo block  300  by fastener  252 . Pin  260  has a head  254  at one end that is pivotally attached to L-shaped bracket  252 . Two collars are disposed about pin  260 . A first collar  290  is fixed to the pin  260  near the end opposite head  254  by fastener  292 , and a second collar  270  is slidably disposed on pin  260  between bracket  250  and first collar  290 . A bias spring  280  is axially disposed about pin  260  between first collar  290  and second collar  270 . Clamp screw  272  extends through a hole  298  in cavity cover  296  and through a threaded transverse bore defined through the second collar  270 . 
   In operation, clamp screw  272  is moved to an unlocked position which permits axial movement of pin  260 , thereby permitting normal operation of the tremolo device to produce tremolo sound effects. With the clamp screw  272  turned into collar  270  to clamp pin  260  in a locked position, pin  260  is prevented from moving axially, thus prohibiting the tremolo block  300  from moving. In the locked position, tuning stability is greatly increased. 
   A third embodiment of the locking and tuning stabilizing device, similar to the second embodiment, is shown in  FIGS. 8 and 9 . In this embodiment, as in the second embodiment, no bores are made in the body of the guitar. The tremolo device is again conventional in construction, and includes tremolo block  300 , tremolo arm  310 , knife-edge  320 , pivot screws  324 , strings  302 , and tremolo springs  210  connected to block  300  by fasteners  216 , and fixed to a bracket attached to the body by fasteners  212 , all of which are similar in construction and operation to the tremolo device discussed above. The tremolo block  300  has a first leg  204  extending parallel to the body of the guitar  100 , and a second leg  206  extending into the cavity  192 . 
   In this embodiment, the locking and tuning stabilizing device includes a clamp bracket  334  fixed to the second leg  206  of the tremolo block  300  by setscrew  336 . The head  254  of pin  260  is defined by a right angle bend in pin  260 . The head  254  is pivotally attached to the clamp bracket  334 . Anchor  328  is fastened against the floor of the cavity  192 . The anchor  328  comprises a “U” bracket  330  or channel that is fastened to the floor of the cavity  192 , and an anchor block  332  or bar pivotally retained within the “U” bracket  330 , pivotal about pivot pin  338 . Because anchor block  332  is pivotally retained within the “U” bracket  330 , the anchor block  332  can be pivoted out of the way for installation. Pin  260  is received in a bore  340  defined longitudinally in anchor block  332 . Clamp screw  272  is engaged in a threaded bore defined in anchor block  332  transverse to the bore  340 , and can be tightened to retain pin  260  in place. Clamp screw  272  extends through a hole  298  in the cavity cover  296 . 
   In operation, clamp screw  272  is moved to an unlocked position which permits axial movement of pin  260 , thereby permitting normal operation of the tremolo device to produce tremolo sound effects. With the clamp screw  272  turned into the anchor block  332  to clamp pin  260  in a locked position, pin  260  is prevented from moving axially, thus prohibiting the tremolo block  300  from moving. In the locked position, tuning stability is greatly increased. 
   It is to be understood that the present invention is not limited to the sole embodiments described above, but encompasses any and all embodiments within the scope of the following claims.

Technology Classification (CPC): 6