Patent Description:
The top of a guitar, electric or acoustic is primarily responsible for the sound quality produced by plucking a guitar string. The action of vibrating strings is governed largely by the structure the strings are anchored to and tensioned across. The more rigid the structure is made, the more the structure is resistant to vibrating. A structure resistant to vibrating will absorb little of the string's energy allowing the string to continue vibrating for an extended length of time. This characteristic of a rigid supporting structure and corresponding longer sustaining string vibration is manifested in a long sustaining musical tone of the instrument; this quality is a benefit to the musician performing on such an instrument.

The disadvantage of a rigid supporting structure is that the imparted limitation on vibration directly impacts the ability of the structure to resonate and convert the vibration of the strings into audible volume. Volume is measured in amplitude of vibration. Volume is necessary for a musical instrument to amplify the vibration of the strings. This is true even when the volume produced by a guitar is amplified electrically as in the case of an electric guitar. The more flexible the supporting structure of the instrument is, the higher the amplitude or potential volume of the produced musical tones.

There exists between the two considerations of the structure supporting the strings a direct opposition. Namely, opposition between the rigidity needed for long sustaining vibration and flexibility needed to produce audible volume in the form of vibrational amplitude. Conventionally, instruments are constructed in a manner which attempts to balance rigidity and flexibility to result in a musical instrument possessing both sustain and volume.

In the case of acoustic guitars, bracing is used on an underside of the guitar top to crease stiffness in certain areas. Electric guitars, because they have much smaller internal spaces in the interior of the body do not lend themselves to structural bracing on the underside of the guitar top. What is needed is a way to tune the sound of an electric guitar by creating tension at predetermined areas of the top. Additionally, there is a need to more effectively and simply attach components to an electric guitar top including a bridge assembly to anchor the strings at the body and to permit easy adjustment of a saddle portion of the bridge assembly in order to change the length of a string that is suspended and permitted to vibrate. <CIT> discloses a tremolo unit for a guitar comprising a bridge fixed to the body of the guitar.

The present disclosure generally comprises a guitar having a body having a bottom and sides and a top. A bridge is attached to the top with at least two anchor bolts extending through the top and secured within a bridge support with a threaded connection between an outer surface of the bolts and an inner surface of the bridge support. A receiver is disposed between each anchor bolt and the inner surface of the bridge support, the receiver having inner threads for a threaded connection to the anchor bolt and outer threads for a threaded connection to the bridge support.

The present invention relates to components of a guitar including the guitar top as well as the guitar bridge assembly and adjustment thereof. More particularly, the invention relates to a novel way of tuning an electric guitar by changing the thickness of the guitar top in predetermined areas to affect rigidity in those areas. Additionally, other embodiments relate to a novel way to anchor a bridge assembly and the provision of a more effective way to adjust a saddle member of the bridge. While the Figures and description of a preferred embodiment relate to an electric guitar, it will be understood that aspects of the invention can be equally valuable when utilized with an acoustic guitar or any other stringed instrument utilizing a top that enhances sound quality.

<FIG> is a top view of an electric guitar <NUM> including some aspects of the invention. The guitar includes a body <NUM> having a top <NUM>, a neck <NUM> attached at one end to the body and a headstock <NUM> formed at an opposite end of the neck. Strings (typically <NUM>) <NUM> run the length of the guitar from a bridge <NUM> located on the guitar top <NUM> to tuning pegs <NUM> located on the headstock. The strings are suspended between a nut <NUM> at the headstock end and a saddle <NUM> located on the bridge <NUM> at an opposite end. The neck <NUM> is equipped with frets <NUM> along its length permitting any or all of the vibrating length of the strings <NUM> to be essentially shortened in order to change their pitch. Because the guitar is an electric guitar, it includes pickups <NUM> as well as tone and volume controls <NUM>.

<FIG> is a perspective view of the guitar body <NUM> with the top <NUM> removed. In the example shown, the guitar is a partially solid guitar shown having a cavity <NUM> formed in the interior of the body and a bridge support <NUM> partially filling the cavity. The top <NUM>, which may be of a different material like a different wood, is typically attached at its lower edge <NUM> to an upper rim <NUM> of the body <NUM> with a glue adhesive (not shown). <FIG> are side and end views respectively of the guitar body <NUM> and top <NUM>. In each Figure, the bridge support <NUM> is visible as well as the upper surface and lower edge <NUM> of the top and the upper rim <NUM> of the body <NUM> that will receive the lower edge <NUM>.

<FIG> are section views of the guitar body <NUM> and top <NUM> of <FIG> taken from <NUM>-<NUM> and <NUM>-<NUM> of <FIG> and showing the bridge support <NUM> as well as the various surfaces of each part. In the embodiment shown, the upper rim <NUM> and the upper surface of the bridge support <NUM> form a convex profile that will create a correspondingly concave shape on the underside of the top <NUM> when it is installed on the body. The existence of the convex profile of the body in each view ensures that the top will be substantially dome-shaped when installed on the body.

<FIG> is a section view taken perpendicular to the direction of the guitar strings <NUM> (not shown) and shows the guitar top <NUM> after it has been attached to the body <NUM> along the upper rim <NUM> the body and lower <NUM> edge of the body. As shown, the upper surface of the top <NUM> has been urged into a convex profile <NUM> corresponding to the convex profile of the upper surfaces of the body <NUM> and bridge support <NUM> and attached at each end to the corresponding edge <NUM> of the body, typically with an adhesive designed for woods. In one example, the top is clamped in its dome-shaped position while drying. In addition to the post attachment, convex profile <NUM> of the top, the original profile <NUM> is shown in dotted lines.

<FIG> is the section view of <FIG> but in addition to showing the original <NUM> and post attachment <NUM> profiles of the top in dotted lines, a profile <NUM> is shown after material has been removed from the outer perimeter of the top <NUM>, resulting in a reduced thickness of the top in the area of attachment to the body <NUM>. The primary reason for removing the material is to reduce the tension in the top that was created when it was bent into the dome-shape. Also shown in <FIG> is the bridge <NUM> visible in <FIG> and used to anchor the strings at the body. The bridge in the embodiment shown is an assembly including a bridge portion <NUM>, an adjustable saddle <NUM> attached to the bridge with adjustment screws <NUM>, and anchor bolts <NUM> used to anchor the bridge to the bridge support <NUM> formed in the body. In practice, the bridge <NUM> would typically be installed and anchored to the bridge support <NUM> after the top <NUM> is installed on the guitar body <NUM>.

<FIG> is an enlarged, more detailed section view illustrating deformation of the guitar top <NUM> brought about by stresses in the top <NUM> as a result of being urged into a dome shape and reduced in thickness in the area of attachment to the body <NUM>. In the example, the post material removal profile <NUM> includes a portion that has been deflected upwards as a result of its thickness being reduced. The original, non-deflected portion is shown in dotted line 210a.

Once the top is installed and the material removed, the top will be in tension or stress on its upper surface, and compression or strain on its underside. Because the top is "bent" not in a single axis but into a multi-axis dome shape, these stresses are magnified many times, resulting in some amount of tension throughout the top.

In one embodiment, the top is bent into a dome shape using the convex profile created by the upper rim <NUM> of the body <NUM> and upper surface of the bridge support <NUM>, and then glued in place. Once the glue is dry, the perimeter of the top can be thinned out, typically in the area of attachment to the body. The material can be removed by sanding or in a preferred embodiment, with a milling machining and cutters, followed by sanding. In another embodiment, material is removed by hand sanding. In the embodiments shown and discussed, the original top <NUM> is essentially a planar member having a uniform thickness. It will be understood however, that the top could initially be somewhat dome-shaped and that initial shape could be further enhanced by installation onto a body having a convex profile along its upper surface as described herein. Similarly, the top <NUM> could be of varying thicknesses initially and then, after installation on the body, its thickness could be further reduced around the perimeter. Additionally, the preferred embodiment presumes a bridge support <NUM> formed in a cavity <NUM> of the guitar body <NUM> that facilitates the bending of the top during installation. The invention could be practiced without a bridge support that functions as a guide for bending the top. Also, while the top <NUM> is described as being done-shaped after installation, it will be understood that due to the differing length and width of the body, the dome-shaped top might not be spherical, but will typically be somewhat elongated in a direction running parallel to the strings.

<FIG> is a section view of the guitar body and top showing the bridge <NUM> anchored to the bridge support <NUM> with one of the two anchor bolts <NUM>. In the embodiment shown, each bolt <NUM> is held by a receiver <NUM> which is an insert having threads formed on an inner <NUM> and outer <NUM> diameters thereof. The receiver <NUM> is typically formed of metal-steel, stainless steel, brass, or potentially aluminum, since these materials resist deformation under the stress imparted to them from string tension on the bridge <NUM> which is transferred to the anchor bolts <NUM>. In one example, the receiver <NUM> is threaded into pre-tapped female threads <NUM> in the guitar top <NUM> and bridge support <NUM>. Thereafter, with the receiver in place, the anchor bolt <NUM> is threadedly inserted. An adjustment nut <NUM> between the upper portion of the receiver and a lower surface of the bridge <NUM> permits the relative height of the bridge and the saddle <NUM> thereabove to be adjusted by a user relative to the guitar top <NUM>. In prior art arrangements, the anchor bolts and any receiver-type device are not threaded. Rather, outwardly extending longitudinal ridges or flutes running the length of the receiver serve to anchor the receiver in the bridge support after the receiver is driven in axially. The arrangement often results in the bolts tipping forward over time due to the force of the tensioned strings urging the bolts in the direction of the headstock. The novel embodiment disclosed herein, because it uses a threaded engagement between the insert and the material of the top and bridge support, results in a more robust and sturdier assembly that is less likely to fail over time.

<FIG> is a section view of the guitar body and top like <FIG>. However, in <FIG> a separate and distinct piece of anchoring material <NUM> is utilized in the bridge support <NUM> for receiving the anchor bolt <NUM>. Separating the anchoring material from the remainder of the bridge support permits the anchoring material to be chosen for its strength and permits the remainder of the support to be a different, more sonically desirable material. In one embodiment, a cavity is formed in the bridge support <NUM>, and the material <NUM> for receiving the anchor bolts is inserted and glued in place prior to the top <NUM> being installed on the guitar body. For example, the material <NUM> for receiving the bolts could be a hard maple, rosewood, or ebony chosen because of the relative hardness of those woods, whereas the main bridge support <NUM> material might be a softer and lighter weight wood like mahogany, alder, ash, or spruce.

<FIG> and <FIG> are top views of a portion of the guitar <NUM> showing the bridge assembly and a pickup <NUM>. The view illustrates some of the same components of the bridge assembly that are visible in <FIG>. In particular, the Figures show a novel arrangement for adjusting the position of the saddle <NUM> relative to the guitar top <NUM>. As explained herein, the length of a guitar string that is permitted to vibrate and sound is that portion that is suspended between the nut at the headstock end of the guitar and the saddle at the bridge end. In one prior art arrangement, the saddle of a guitar is adjusted by adjusting the bridge upon which it is mounted. In another prior art arrangement, the saddle can be independently adjusted but only by removing the entire bridge assembly in order to access certain fasteners. In the embodiment shown, the saddle <NUM> is adjustably mounted on the bridge <NUM> with adjustment screws <NUM>, each of which is mounted in a slot <NUM> formed at each end of the saddle <NUM>. The screws and slots are constructed and arranged to permit the adjustment of the saddle towards and away from the headstock of the guitar, thereby increasing or decreasing the length of a string that is supported between the saddle and nut and permitted to vibrate when plucked. In every case, the saddle adjustment is accomplished without disturbing the location of the bridge.

In <FIG> for example, the screws <NUM> are both seated at a closed end of their respective slot <NUM>, resulting in a relatively short length of string available for vibration. <FIG> shows one possible adjustment of the saddle <NUM> in relation to the bridge <NUM>. In the example, a left side of the saddle <NUM> remains in its original position in its slot <NUM> while the adjustment screw of the right side of the saddle has been loosened and the right side of the saddle essentially rotated clockwise and then re-tightened, thereby changing the position of the right side of the saddle and creating a distance <NUM> and an angle <NUM> between the right and left sides of the saddle. The result of the arrangement in <FIG> is that a longer length of the larger diameter strings is available for vibrating compared to the smaller diameter strings. While the slots <NUM> are illustrated in the Figures as having an open end and a closed end, an open end is not necessary as a closed slot could still permit the desired movement of the saddle and screw <NUM> within the slot <NUM>.

Claim 1:
A guitar (<NUM>), the guitar (<NUM>) comprising:
a body (<NUM>), the body (<NUM>) having a bottom, sides, a top (<NUM>), and a cavity (<NUM>) formed in an interior thereof and a bridge support (<NUM>) formed within the cavity (<NUM>);
a neck (<NUM>) extending from the body (<NUM>);
a bridge (<NUM>, <NUM>) attached to the top (<NUM>) with at least two anchor bolts (<NUM>) that extend through the top (<NUM>), and a receiver (<NUM>) having inner threads (<NUM>) for a threaded connection to the anchor bolt (<NUM>) and outer threads (<NUM>),
characterized in that
the anchor bolts (<NUM>) are secured within the bridge support (<NUM>) with a threaded connection between an outer surface of the bolts (<NUM>) and an inner surface of the bridge support (<NUM>); in that
the receiver (<NUM>) is disposed between each anchor bolt (<NUM>) and the inner surface of the bridge support (<NUM>), and in that the outer threads (<NUM>) of the receiver (<NUM>) are for a threaded connection to the bridge support (<NUM>).