WO2000033290A1

WO2000033290A1 - A guitare bridge

Info

Publication number: WO2000033290A1
Application number: PCT/ZA1999/000129
Authority: WO
Inventors: René Uberbacher
Original assignee: Uberbacher Rene
Priority date: 1998-12-01
Filing date: 1999-11-30
Publication date: 2000-06-08
Also published as: ZA200003672B; AU2060200A

Abstract

A guitar bridge assembly is provided for use in creating sound effects of the general nature known as 'note bending', vibrato or chord changing by causing an increase or decrease in the tension in the guitar strings (6). The bridge assembly is used in combination with an integrated or separate set of intonation supports and comprises a movable anchor unit (11) providing an anchoring formation (13), for a free end of each string of an associated guitar. The anchor unit is rotatable or swivelable about an axis transverse to the direction in which strings of an associated guitar extend by means of an operating member (16). The anchor unit has individual adjustment means (14, 15) for cooperation with each guitar string to enable independent adjustment to be made of the amount of change in tension in an associated guitar string that is created by a particular extent of movement of the operating member.

Description

A GUITAR BRIDGE

FIELD OF THE INVENTION

This invention relates to a guitar bridge and, more particularly, to a guitar bridge which enables the tension in the strings of a guitar to be varied in order to achieve certain sound effects such as those known as "note bending"; "vibrato"; and "chord changing". Such effects are, as far as applicant is aware, generally achieved by means of a controlled decrease in the tension in the relevant guitar strings and the unit used to achieve this is sometimes referred to as a vibration control unit.

It is to be noted that the term "guitar" as used in this specification is to be interpreted broadly and is intended to include any appropriate instrument having a body with a sound table; a neck carrying a finger board with frets; and strings held tightly over the sound table and finger board for creating the desired sounds.

BACKGROUND TO THE INVENTION

Various mechanisms have been proposed in order to achieve the controlled variation of the tension in guitar strings with a view to producing sound effects of the general type indicated above.

As far as applicant is aware the most common of these is the so-called Tremolo bridge system in which a bridge assembly is supported on the sound table in a manner such that it can swivel about an axis roughly in the region of the face of the guitar. The bridge assembly is biased to a position in which the guitar strings are kept in tension, usually by means of a spring positioned within the guitar body and acting on an arm extending inwardly from the bridge assembly. A lever is attached to the bridge assembly so that it can be moved against the spring bias to decrease the tension in the guitar strings and thereby create sound effects of the type indicated above. The bridge assembly includes an adjustable, individual intonation support and guide for each string which passes over such support and downwardly towards the inner end of the arm to which the free end of the string is attached. Each of these supports is adjustable in position approximately in the plane of the strings so as to be capable of adjusting the effective length of the associated string between its base fret and the support so that the correct intonation or tuning can be achieved for each string.

This arrangement suffers from a number of limitations. Firstly, because of the different characteristics of each string, the decrease in frequency, and thus pitch, achieved by a particular degree of movement of the lever is different for each string. Thus a true change in pitch of two or more strings cannot be achieved simultaneously as one of them would deviate from its true relationship to the other. Secondly, the only control over the degree of movement of the lever is the force applied to it by the particular guitarist and, accordingly, the decrease in pitch achieved depends entirely on the skill of the guitarist. There is also no means of catering for different strengths of guitarist in that the force needed to be applied to the lever is not adjustable in any way. In addition to this, fitting of a tremolo system to an electric guitar may require considerable modification of the guitar, in particular, hollowing out a portion of the body to receive the tension springs and associated arm.

OBJECT OF THE INVENTION

It is an object of this invention to provide a guitar bridge assembly, and guitar embodying same, in which at least some of the disadvantages of the tremolo system are obviated. SUMMARY OF THE INVENTION

In accordance with one aspect of this invention there is provided a guitar bridge assembly for use in combination with an integrated or separate set of intonation supports which provide support for each string of a guitar with which the bridge is to be associated, the bridge assembly comprising a movable anchor unit providing an anchoring formation for a free end of each string of an associated guitar and wherein the anchor unit is rotatable or swivelable about an axis transverse to the direction in which strings of an associated guitar extend, and an operating member attached to the anchor unit for moving it about said axis by means of the hand of a guitarist playing the guitar, the bridge assembly being characterized in that the anchor unit has individual adjustment means for cooperation with each guitar string to enable independent adjustment to be made of the amount of change in tension in an associated guitar string that is created by a particular extent of movement of the operating member.

Further features of the invention provide for the anchor unit to include an adjustable saddle element for each guitar string to adjust the distance between the saddle element and said transverse axis, or alternatively, for the anchoring formation for each string to be longitudinally adjustable relative to said transverse axis; for each saddle element to have a fulcrum for engaging the associated string; for each saddle element to be longitudinally adjustable in the general direction of the guitar strings; for an adjustable stop to be included to limit movement of the anchor unit to that corresponding to a required change in pitch; for the resistance to movement of the anchor unit to be adjustable, conveniently using a compression spring with a screw threaded adjustment member; for the sensitivity or amount of movement required of the lever to achieve a certain change in pitch to be adjustable, in particular by adjusting the position of the said axis in a direction towards and away from the sound table; and for the anchor assembly to be pivotally attached to a base in turn adapted to be secured to the sound table by means of fasteners.

The anchor unit is preferably rotatable or swivelable in a direction tending to increase tension in the strings in which case the anchor unit cooperates with a fixed stop to hold it in its normal position and the lever serves to move the anchor unit to increase tension in the strings. In this case the normal position of the anchor unit does not require springs to keep it in place and, accordingly, the tuning of the strings in their normal position remains substantially constant.

However, the invention includes with its scope an arrangement in which movement of the anchor unit tends to decrease tension in the strings and, indeed, the invention is intended to include an arrangement in which the anchor unit could be moved in either of two directions in order to selectively increase or decrease tension in strings with the attendant increase or decrease in pitch. In these instances a spring bias in the arrangement would undoubtedly be required with a central normal position defined, for example, by means of a suitable cam cooperating with a formation associated with the anchor unit or base to which the latter is attached.

In accordance with a second aspect of the invention there is provided a guitar comprising a body having a sound table, and a neck having a finger board with frets extending from the body, the body having a bridge as defined above attached thereto so that the anchoring formations associated with the anchor unit can receive the free ends of the guitar strings and an intonation piece, either integral or separate from the bridge assembly and defining a support for each of the guitar strings between the anchor unit and neck.

It will be understood that by using the intonation piece to achieve normal tuning of the strings and the individual adjustment means of this invention on the anchor unit to "tune" the strings individually to the higher semitone, for example, the sound effects indicated above can be achieved on any combination of the strings simultaneously and even on chords strummed on all of the strings.

In order that the above and other features of the invention may be more fully understood various embodiments thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings :-

Figure 1 is a schematic illustration of a guitar, typically an electric guitar;

Figure 2 is a schematic side elevation illustrating the main concept of the invention in one embodiment thereof;

Figure 3 is a view similar to Figure 2 the illustrating the anchor unit rotated in a direction to increase tension in the guitar strings;

Figure 4 is a plan view of a preferred bridge assembly;

Figure 5 is a side view of the bridge assembly illustrated in Figure 4 and illustrating in cross-section an anchoring formation for a string and an associated adjustable saddle unit having a fulcrum engaging the string ;

Figure 6 is an isometric view of a second embodiment of the invention; Figure 7 is an exploded rear isometric view of the anchor unit of the embodiment illustrated in Figure 6;

Figure 8 is an isometric view of a third embodiment of the invention in which the intonation supports are integral with the anchor unit; and,

Figure 9 illustrates a still further embodiment of invention in side elevation.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

Referring firstly to Figure 1 , the bridge (1) of this invention is adapted to be secured to the sound table (2) of a guitar body generally indicated by (3) in place of the conventional bridge (not shown). A separate intonation piece (4) has an individual support roller (5) (see Figures 2 to 5) for each string (6) and is spaced forward of the bridge (1). The normal note sounded by any string is therefore determined by the tension in the string and the length of string between the intonation piece and the relevant fret (7) on the finger board (8) of the guitar. The support rollers are adjustable for fine tuning purposes.

In the preferred embodiment of the invention the bridge assembly comprises a base (9) which is simply secured to the face of the sound table by means of screws or bolts. The base has a pair of laterally spaced coaxial journals (10) which pivotally support an anchor unit (11). The axis of the journals is, in this case, located above the anchor unit itself as indicated by numeral (12) in Figures 2, 3 and 5.

In this embodiment of the invention the bridge assembly is made for use on a conventional electric guitar having six strings. An anchor formation is provided for each of these strings at the rear of the anchor assembly as indicated by numeral (13) (see Figure 5). Also associated with each string is a saddle unit (14) adjustable in position by means of a screw threaded adjuster (15) so that the position of the saddle in the direction of the guitar string 6 can be adjusted within the anchor unit. Each of the saddle units has a fulcrum (14a) extending downwards onto the relevant string with the fulcrum being adapted to engage and pull on the relevant string when the anchor assembly is rotated about the journals. Rotation is achieved using a hand operable lever (16) attached to an anchor point rearwards of the journals.

The arrangement is such that the tension in the strings holds the anchor assembly in a rest position in which it engages a cooperating formation on the base and is in the position illustrated in Figure 2. When it is decided to create a sound effect by increasing the tension in the strings the lever can be rotated towards the sound table and an increase in frequency and thus pitch can be achieved. The extent of rotation is preferably limited by means of a suitable adjustable stop (17) (see Figure 4).

It will be understood that, when the lever is operated until movement of the anchor assembly is arrested by the stop, an increase in tension will be applied to the portion of the string extending between the intonation piece (4) and the anchor formation (13). The extent of the increase in tension will depend, in each case, on the exact position of the fulcrum of the relevant saddle unit and that, accordingly, the change in pitch occasioned by the movement of the anchor unit can be adjusted. What this means is that the six saddles can be adjusted so that the increase in pitch of each of the strings is proportional to each other and, accordingly, there is no limit to the number of strings that can be played simultaneously prior to implementing one of the sound effects indicated above. Thus the increase in pitch may be set at a semi-tone in each string at the point where the lever is arrested by the stop. This is a totally different situation from that which has applied in all prior art cases of which applicant is aware. In this embodiment of the invention the sensitivity, by which term is meant the distance by which the lever must be moved to achieve movement of the anchor assembly to a position in which it is arrested by the stop, can be adjusted. In order to achieve this the journals (12) are adjustable in height above the surface of the sound table. The height adjustment is achieved using grub screws (18), one of which is associated with each journal. Also, it is to be noted that for convenience of operation of the lever it is rotatable about an axis at right angles to the axis if the journals, ie it is rotatable in a plane roughly parallel to the sound table.

Turning now to the embodiment of the invention illustrated in Figures 6 and 7, the assembly once more includes an intonation piece (30) in which the support rollers (31 ) are individually adjustable by means of screws (32). In this case the base (33) supports an anchor unit (34) in which there are six individually adjustable anchor elements (35) each having an anchor formation (36) for its associated string (37). In this case the relative degree of tension change in the six strings is adjusted by adjusting screws (38) (see Figure 7) which move the individual anchor elements (35) in the general direction of the strings.

In this case the axis of rotation of the anchor unit is nearer the surface of the sound table and, accordingly, the normal position of the anchor unit is a raised one and the anchor unit is pushed downwards in order to increase the tension in the strings. The limit of movement of the anchor unit is defined by a screw (39) cooperating with a lug (40) at the rear of the anchor unit such that the free end (41) of the screw (39) forms a stop by engagement with a zone (42) on the base.

In this embodiment of the invention movement of the anchor unit is achieved using a hand operable plate (43) which serves also as a cover for the anchor unit. The plate (43) is pivotally attached to the anchor unit by pivots (44) and it engages, in the first place, a head (45) of a screw (46) which in turn cooperates with a compression spring (47). The effect of this is that the force required to be exerted on the plate in order to initiate movement of the anchor unit about its pivots (49) can be adjusted. It is also possible to adjust the base position of the plate in this example of the invention. This is achieved through the medium of a further adjustable bolt 43a (see Figure 7) which transmits the movement of the plate to the anchor unit 34.

Turning now to Figure 8 of the drawings there is illustrated a similar embodiment of the invention but one in which the intonation support rollers (50) are embodied in the anchor unit itself.

Figure 9 illustrates an embodiment of the invention in which the anchor unit

(51) swivels, as opposed to actually rotating, about a mounting attachment

(52) on a base (53).

It will be understood that numerous variations may be made the embodiments of the invention described above without departing from the scope hereof. In particular, the invention may be applied a device in which the tension in the strings is decreased and thus creates sound effects similar to those created by the existing tremolo units. However, in contradistinction to existing tremolo units the effect can be achieved simultaneously on a plurality of strings in consequence of the individual adjustment thereof insofar as the degree to which tension is increased or decreased in each string may be adjusted by the adjustment means.

Claims

CLAIMS:-

1. A guitar bridge assembly (1) for use in combination with an integrated or separate set of intonation supports (5,31 ,50) which provide support for each string (6,37) of a guitar (3) with which the bridge is to be associated, the bridge assembly comprising a movable anchor unit (1 ,34) providing an anchoring formation (13,) for a free end of each string of an associated guitar and wherein the anchor unit is rotatable or swivelable about an axis transverse to the direction in which strings of an associated guitar extend, and an operating member (16,43) attached to the anchor unit for moving it about said axis by means of the hand of a guitarist playing the guitar, the bridge assembly being characterized in that the anchor unit has individual adjustment means (11 ,35) for cooperation with each guitar string to enable independent adjustment to be made of the amount of change in tension in an associated guitar string that is created by a particular extent of movement of the operating member.

2. A guitar bridge assembly as claimed in claim 1 in which the anchor unit includes an adjustable saddle element (1 1 ) for each guitar string to adjust the distance between the saddle element and said transverse axis.

3. A guitar bridge assembly as claimed in claim 1 in which the anchoring formation (36) for each string is longitudinally adjustable relative to said transverse axis.

4. A guitar bridge assembly as claimed in claim 2 in which each saddle element has a fulcrum (14) for engaging the associated string.

5. A guitar bridge assembly as claimed in either of claims 2 or 4 in which each saddle element (35) is longitudinally adjustable in the general direction of the guitar strings.

6. A guitar bridge assembly as claimed in any one of the preceding claims in which an adjustable stop (39) is included to limit movement of the anchor unit to that corresponding to a required change in pitch.

7. A guitar bridge assembly as claimed in any one of the preceding in which the resistance to movement of the anchor unit is adjustable.

8. A guitar bridge assembly as claimed in claim 7 in which the resistance to movement is provided by a compression spring (47) with a screw threaded adjustment member (45).

9. A guitar bridge assembly as claimed in any one of the preceding claims in which the sensitivity or amount of movement required of the lever to achieve a certain change in pitch is adjustable.

10. A guitar bridge assembly as claimed in claim 9 in which the sensitivity is adjustable by adjusting the position of the said axis in a direction towards and away from the sound table.

11. A guitar bridge assembly as claimed in any one of the preceding claims in which the anchor unit is pivotally attached to a base ( 9,33,53) in turn adapted to be secured to the sound table of a guitar by means of fasteners.

12. A guitar bridge assembly as claimed in any one of the preceding claims in which the anchor unit is rotatable or swivelable in a direction tending to increase tension in the strings and the anchor unit cooperates with a fixed stop to hold in its normal position.

13. A guitar bridge assembly as claimed in any one of claims 1 to 11 in which the anchor unit tends to decrease tension in the strings.

14. A guitar bridge assembly as claimed in any one of claims 1 to 11 in which the anchor unit is selectively movable in either of two directions in order to selectively increase or decrease tension in strings with the attendant increase or decrease in pitch.

15. A guitar comprising a body having a sound table, and a neck having a finger board with frets extending from the body, the body having a bridge as claimed in any one of the preceding claims attached thereto with the anchoring formations associated with the anchor unit receiving the free ends of the guitar strings and an intonation piece, either integral or separate from the bridge assembly defining a support for each of the guitar strings between the anchor unit and neck.