A vibrato device for guitars which is easily omnidirectionally adjustable by a clamp screw and a pivot screw concentric therewith, both conveniently accessible from the rear of the device, and by elevation screws mounted in the string-supporting saddles and conveniently accessible from the top of the device. The brass saddles are provided with a steel block insert for improved resonance and damping, and the control lever can be conveniently either locked in one position, or allowed to swing freely, at any time during play. The device is provided with self-centering straight knife-edge bridge pivots. The free ends of the strings are clamped to the bottom of a steel sustain block depending from the bridge of the device, and the clamp screws for both the strings and the lateral saddle position adjustment are turnable with coins.

This invention relates to a vibrato device for guitars, and more 
particularly to a device which provides an improved clarity of tone and 
improved multidirectional adjustability. 
BACKGROUND OF THE INVENTION 
Vibrato systems for guitars are well known as shown, for example, in U.S. 
Pat. No. 4,171,661. These systems are generally sold as an attachment to 
existing guitars and can be operated by way of an actuating lever to 
simultaneously relax the tension of all the strings of the guitar to a 
small degree, thereby detuning it slightly. 
Existing vibrato systems have the disadvantage of being difficult to adjust 
for various string spacings, and producing a harsher sound than desirable. 
Furthermore, a number of guitarists consider it desirable to have the 
opportunity of leaving the actuating lever in a forward position between 
uses, or to have it swing out of the way under its own weight whenever it 
is not in use. 
SUMMARY OF THE INVENTION 
The present invention overcomes the problems of the prior art by providing 
a vibrato system in which each of the individual string guides or saddles 
are easily and independently adjustable transversely of the guitar to 
allow adjustment of the individual spacings of the strings. This 
adjustment is accomplished by an arrangement in which the string-carrying 
saddle is pivotable vertically about the head of a longitudinal adjustment 
screw mounted concentrically, and constrained by a vertical slot, within a 
lateral adjustment clamping screw. The tone of the system is improved by 
the use of a steel string guide insert in each of the brass saddles. In 
accordance with another aspect of the invention, the actuating arm can be 
selectively, by a flick of the finger, either locked in a predetermined 
position with respect to the vibrato device, or unlocked so that it can 
freely swing to a position dictated either by gravity or by the player as 
the vibrato device is being used.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows guitar 10 of conventional construction to which the vibrato 
device 12 of this invention has been attached. It will be noted in the 
detail of FIG. 2 that when the vibrato system of this invention is used, 
the strings 14 are strung in the opposite direction from normal, i.e. with 
the ball end 16 at the tuning key 18 rather than on the body of the 
guitar. The reason for this arrangement is that when a vibrato device is 
used, the strings are periodically relaxed and tightened. If the strings 
are strung in the normal way, with their free ends wound around the tuning 
key 18 in multiple turns, the action of the vibrato device gradually 
shifts the position of the string windings on the tuning key with respect 
to one another, resulting in a slight detuning of the instrument. 
By winding the free ends of the strings 14 around the retaining screws 20 
at the bottom of the vibrato device 12 as shown in FIGS. 4, 8 and 9, it is 
possible to tune the guitar with only about one-half of a turn of the 
string 14 around the key 18, thus eliminating the abovementioned source of 
undesired detuning. The heads of the retaining screws 20 are preferably 
provided with slots 21 wide enough to receive a coin for tightening or 
loosening the screws 20. 
As best shown in FIGS. 3 and 4, the vibrato device 12 consists of a bridge 
22 and a steel sustain block 24 integrally attached thereto and depending 
therefrom. At its forward end, the bridge 22 has knife-edge protrusions 26 
which engage V-notches 40 in a bearing 30 attached to the upper surface of 
the guitar 10. The sustain block 24 carries on its underside a plate 32 
which is pulled toward the left in FIG. 4 by springs 34 attached to a 
bracket 36 fixed to the underside of the guitar 10. It is important that 
the ends of the springs 34 be firmly attached to the plate 32 of the 
sustain block 24 so that the ends of the springs 34 cannot change their 
position with respect to the sustain block 24 in the slightest during 
play. This prevents unintended detuning of the guitar. (The attachment of 
the other end of springs 34 is not critical as those ends do not move 
significantly during play.) 
The curved edges 37 of V-notches 40 assist in centering the bridge 22 with 
respect to bearing 30 without interfering with the free movement of knife 
edge 26 about the transverse horizontal pivot axis defined by it. The 
straight shape of knife edge 26 prevents the binding and misadjustment 
observed with the conventional screwhead pivot bearings of the prior art. 
Normally, the tension of the spring 34 and the strings 14 is such as to 
maintain the bridge 22 in equilibrium in a horizontal position in FIG. 4. 
By manipulating the control arm 38, the guitarist can cause the bridge 22 
to pivot about the knife-point edge 40 so as to temporarily relax the 
tension in the strings 14 to change the tone of the guitar. By 
appropriately manipulating the control of arm 38, an alternating 
tensioning and relaxing of the strings 14 can be achieved so as to produce 
a vibrato effect. When the control arm 38 is released, the vibrato device 
12 returns to its equilibrium position in which the guitar 10 is exactly 
in tune. 
As best shown in FIGS. 3 and 8, the strings 14 are individually threaded 
over guide blocks 54 of saddles 42, and through string channels 44 in the 
balance block 24, to be tied down at the retaining screws 20. 
In accordance with this invention, the saddles 42 can be independently 
moved in two horizontal and one vertical direction to accommodate various 
string heights and string spacings by means of the mechanism depicted in 
detail in FIGS. 5 through 7. 
Turning first to FIG. 5, one of the saddles 42 is shown in detail in this 
exploded view. The saddle 42 consists of a hollow brass body 50 which is 
cut out at the front, as at 52, to receive a steel guide block 54. It is 
well known among guitar manufacturers that the use of steel at the points 
of attachment of strings gives a guitar a desirable resonance; however, 
the use of an excessive amount of steel results in excessive resonance 
which must be attenuated by the interposition of a less resonant vehicle 
between the steel guide block 54 and the base of the bridge 22. This 
problem had previously been solved by mounting a flexible sheet steel 
string support on a brass base, but it was found that this expedient 
tended to result in an eventual detuning of the guitar. In accordance with 
the present invention, a solid steel guide block 54 is inserted into the 
front end of the saddle. The solid nature of guide block 54 avoids 
deformation and maintains its position with respect to the body 50 of the 
saddle 42. In this manner the string 14 is firmly held in place on the 
resonant guide block 54, yet the material of the brass saddle 42 is 
interposed completely between the guide block 54 and the steel sustain 
block 24. 
The vertical position of the saddle 42 can be adjusted to conform to the 
desired heights of the strings 14 above the guitar's finger board by means 
of elevation screws (FIG. 6), which are threaded into the vertical 
openings 58 in the saddle body 50. In this manner, as best seen in FIG. 7, 
the string 14 touches only the guide block 54, whose groove 60 centers 
string 14, and descends into the balance block 24 (FIG. 4) without 
touching the body 50 of saddle 42. 
The saddle 42 is connected to the spacing block 62 in a vertically free but 
horizontally restrained manner by the pivot screw 64 which is threaded 
into the opening 66 of saddle 42. As best seen in FIG. 7, the channel 68 
of spacing block 62 is sufficiently high to allow the pivot screw 64 to 
pivot about point 70 (FIG. 7; see also dot-dash lines in FIG. 8) as the 
front end of saddle 42 is raised. On the other hand, the width of the 
channel 68 is essentially the same as the diameter of pivot screw 64, so 
that the screw 64, and with it saddle 42, cannot move sideways with 
respect to spacing block 62. The position of saddle 42 can be adjusted in 
a forward rearward (i.e. axial) direction by tightening or loosening the 
pivot screw 64 against the bias of spring 72. 
The transverse horizontal position of the saddle 42 can be adjusted by 
loosening the clamp screw 74 and sliding the spacing block 62 transversely 
on its flat surfaces 82 within the guide slot 76 formed in the bridge 22 
(FIG. 10). For this purpose, the clamp screws 74 are preferably provided 
with a slot 75 of a width suitable to permit the use of a coin for turning 
the clamp screw 74. Following a transverse horizontal adjustment, the 
spacing block 62 can be fixed in place by tightening the clamp screw 74 on 
the screw thread 78 of spacing block 62 so as to pinch the shoulder 80 
(FIG. 8) between the clamp screw 74 and the spacing block 62. It will be 
noted that the clamping of clamp screw 74 does not affect the vertical 
mobility of pivot screw 64, which remains freely vertically movable at all 
times. Saddle 42 is held down against the bridge 22 by the tension of the 
string 14. 
FIGS. 8 and 9 illustrate the routing of strings 14 over the guide blocks 54 
and down through individual channels 44 to the retaining screws 20 on the 
underside of the balance block 24. It will be seen that in this manner, 
the string 14 contacts only steel portions of the vibrato device, while 
any resonance resulting therefrom is attenuated by the interposition of 
the brass saddle 42 between the string and the base of the bridge 22. By 
tightening the free end of the string 14 on the vibrato device while 
positioning their ball ends at the keys on the neck of the guitar, 
detuning of the guitar by repeated operation of the vibrato device is 
effectively avoided. 
FIGS. 11 and 12 illustrate another feature of this invention. It is 
sometimes convenient for a guitarist to have the control arm 38 in a 
position pointing toward the neck of the guitar where it can be readily 
grasped for the operation of the vibrato device 12. At other times, the 
same guitarist may want the control lever 38 completely out of the way so 
as not to interfere with the ordinary playing of the guitar. The present 
invention makes it possible to rapidly switch between these two conditions 
by providing a control lever lock 89. A locking lever 90 is attached to a 
locking screw 92 in such a manner as to allow the control lever 38 to turn 
freely within the bore 94 in bridge 22 when the locking lever 90 is in the 
down position shown in FIG. 12 (and in dotted lines in FIG. 11), while 
locking the control lever 38 against rotation within the bore 94 when the 
locking lever 90 is in the horizontal position as shown in solid lines in 
FIG. 11. In order to allow this rather sensitive adjustment, the locking 
lever 90 and screw 92 are preferably two pieces releasably interconnected 
by serrations 96 which allow the relative positions of screw 92 and 
locking lever 90 to be varied for an accurate adjustment. 
With this arrangement, the guitarist may bring the lever 90 to a horizontal 
position as long as he wishes to use the vibrato devices, and he can then 
flip it to the vertical position with a quick and simple flick of the 
finger. With the locking lever 90 in the vertical positions of FIGS. 11 
and 12, gravity will cause the control lever 38 to pivot within the bore 
94 to a position transverse of the vibrato device 12 when the guitar is 
held in its normal playing position against the guitarist's body.