US3535975A

US3535975A - Stringed musical instrument neck incorporating automatic warp and bow prevention means

Info

Publication number: US3535975A
Application number: US868268A
Authority: US
Inventors: Paul Daniel Broussard
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-10-06
Filing date: 1969-10-06
Publication date: 1970-10-27
Anticipated expiration: 1987-10-27

Description

United States Patent 1 13,535,975

[72] Inventor Paul Daniel Broussard [56] References Cited Andrew, Muisiana (1009 Hebe", UNITED STATES PATENTS 2,335,244 11/1943 Gugino 84/293 P 68,268 2,497,116 2/1950 Dopyera.... 84/293 [22] Oct-@1969 3,418,876 12/1968 Dopyera 84/293 Continuation-impart of application Ser. No. 724,902, April 29, 1968, abandoned.

[45] Patented Oct. 27, 1970 [54] STRINGED MUSICAL INSTRUMENT NECK INCORPORATING AUTOMATIC WARP AND BOW Primary Examiner-Richard B. Wilkinson Assistant Examiner-John F. Gonzales ABSTRACT: Basically, in a stringed musical instrument having a neck pivotably connected to the instrument body, the

improvement comprising, a neck height adjustment means' PREVENTION MEANS 10 Claims, 8 Drawing Figs.

[51] Int.Cl Gl0d3/00 [50] Field of Search 84/293 been such that neck bowing and warping in some instances was not controlled at all, while in other instances the neck incorporated a truss rod or rods which required periodic manual adjustment after having been preset at the factory, thus in such a case the periodic manual adjustments have to be made by trial and error with no guarantee of precise adjustment. If such prior truss rod or rods are overtightened this either causes neck warping and bowing or breakage of the internal truss rod. Furthermore, if such prior truss rod or rods are not capable of being adjusted the neck will warp and bow excessively. In addition, prior art warp and bow prevention means are not self-adjusting thus susceptible to substantial improvement.

It is an object of the present invention to provide an automatically self-adjusting neck bow and warp prevention means to control and prevent excessive neck bending, warping, and bowing.

In the drawings:

FIG. 1 is a face plan view of an instrument incorporating the present invention;

FIG. 2 is a side view of an instrument incorporating the present invention;

FIG. 3 is a back plan view of an instrument incorporating the present invention;

FIG. 4 is a face plan view of an instrument body incorporating the present invention;

FIG. 5 is a back plan view of an instrument neck incorporating the present invention;

FIG. 6 is an enlarged fragmentary transparent side view of an instrument incorporating the present invention;

FIG. 7 is an enlarged fragmentary sectional view taken substantially along line 4-4 in FIG. 6; and

FIG. 8 is an enlarged fragmentary sectional view taken substantially along line 5-5 in FIG. 6.

Referring to the drawings, the present invention shown in FIGS. 1 and 2 incorporates a body 10, a neck 11, tuning keys 12, strings 13, a bridge 14, a tailpiece 15, pickups l6 and 17, controls 18, 19, and 20, a jack 21, and switches 22 and 23. The instrument back 24 is shown in FIGS. 2 and 3 while the instrument sides 25 are shown in FIG. 2. The

shoulder strap buttons

26 and 27 are shown in FIGS. 1, 2, and 3.

The instrument neck 11 shown in FIGS. 1, 2, 3, 5, 6, 7, and 8 is mounted to the instrument body 10 by a hinge 28 shown in FIGS. 2, 3, 4, 5, 6, and 8. One half of the hinge 28 shown in FIG. 5 is mounted to the neck 11 with the

mounting screws

29, 30, and 31 while the other half of the mounting hinge 28 shown in FIG. 4 is mounted to the instrument body 10 with the

mounting screws

32, 33, and 34, and the neck 11 is held in place by the hinge pin 35 which is shown in FIG. 4. It is emphasized that the hinge pin 35 relationship to the hinge 28 should be precision fitting, that is a precise and close tolerance fit, so that the hinge 28 will swivel only in the direction it is manufactured to swivel. If otherwise this allows a slight shift which in turn may cause inaccurate string vibration or string detuning. Furthermore, with the present specific example and the present stringed instrument tuning tension such as for a standard guitar, the hinge 28 should be no less than a full onesixteenth of an inch thick or more such as of plated steel or of equivalent strength, otherwise if the hinge strength is below requirements the hinge 28 will bend with and due to the applied string tension.

Due to the string pull caused by tensioned strings 13 causes neck warping and bowing as well known in the art, thus the present invention utilizes preferably a cylindrical truss rod 36 which is embedded in a routed groove or channel provided for such purpose between the finger board 37 and the neck base 42 as shown in FIGS. 5, 6, 7, and 8. At one end of the truss rod 36 nearest the tuning keys 12 the rod 36 may be straight or preferably bent at an angle. This angle bend in the rod 36 indicated by dashed line 38 in FIGS. 6 and 7 is not critical thus may be any angle such as from 2 to from parallel to the longitudinal axis of the surface of the fretboard 37, and preferably the rod 36 should have a slight curve and are along its length similar to that indicated by dashed line 38 but producing a lesser angle and curve, while near the other end of the truss rod 36 nearest the end of the neck 11 preferably should be bent approximately 90 from parallel to the longitudinal axis of the surface of the fretboard 37 as showniin FIGS. 6 and 8. This approximate 90 bend is indicated by 39in FIGS. 6 and 8, at which point the end of the truss rod 36 traverses the neck base 42 and terminates fitting into the hole provided in the supporting and stopping threaded member 40, but the rod 36 does not thread into the supporting member 40. Instead, the truss rod 36 fits into the hole drilled or formed into the supporting and stopping member 40 as shown in FIGS. 6 and 8. The truss rod supporting and stopping threaded member 40 threads into the instrument body 10 and is inserted through the gear insert member 41 which is pressed into the body 10 to prevent raw wood edge as well as provide a screwdriver guide for neck height adjustment. It is emphasized, the truss rod supporting and stopping member 40 in FIGS. 6 and 8 is provided for neck height adjustment and is not a manual adjustment of the rod 36 nor a manual adjustment of the tension to be imposed upon the rod 36 as is required in prior art.

It is also of utmost importance and greatly emphasized, the groove or channel between the fingerboard 37 and the neck base 42 provided for the truss rod 36 to be inserted and embedded therein has to have free play as apparent in FIGS. 6, 7, and 8. That is a slight clearance between the rod 36, the fingerboard 37 and the neck base 42. Thus the said groove or channel embedding the said rod is to be slightly larger than the truss rod 36. Therefore, so that the glue used to glue the fingerboard 37 to the neck base 42 does not adhere to the rod 36, the rod 36 preferably may be insulated by fitting the rod 36 into a thin plastic tubing or coating such as Teflon tubing or the rod 36 may be coated with heavy grease such as axle grease prior to placing the rod 36 into position and permanently embedding it between the fingerboard 37 and the neck base 42. If the rod 36 is not free to move slightly along its entire length let it be clearly understood that the rod 36 in such a case will not function properly or may not function at all.

An exact 90 bend in the rod 36 near the end of the neck 11 indiwted by 39 in FIGS. 6 and 8 is again not a precise requirement. In fact, the rod 36 may be bent at other angles such as illustrated by dashed line 43 in FIG. 6 which represents an approximate 70 angle from the longitudinal axis of the strings 13.

The rod 36 shown in FIGS. 6, 7, and 8 may be of any suitable material which will withstand the applied string pressure, but has to be soft and flexible enough to bend, conform to the aforesaid groove or channel, and free to move alongits length, such as of preferably soft steel or brass. A specific size which may be used for example may be approximately three-thirtyseconds of an inch in diameter. Furthermore, the rod 36 preferably may be weakened, such as by scoring in the general area of the 90 bend 39 in FIGS. 6 and 8 to reduce the pressure required to cause the rod 36 to move forwards. In fact, in such a case a larger diameter rod may then be used.

In the operation of the neck 11 shown in FIG. 5, the neck 1 may be mounted, removed, replaced, or exchanged with the hinge pin 35 shown in FIG. 4 while the height of the neckll may be adjusted by application of a screwdriver to the slot provided in the truss rod supporting and stopping threaded member 40 shown in FIGS. 6 and 8.

Shown in FIG. 6, as the tension is applied to the strings l3 such as by the tuning keys 12 this causes a corresponding tension upon the neck 11, causing the neck 11, the neck mounting hinge 28, and the rod 36 to swivel in the direction of the supporting and stopping threaded member 40, however the truss rod supporting and stopping threaded member 40 stops the rod 36 from swiveling thereby causing a corresponding equal counter tension, pressure, and force to be exerted and applied to the rod 36 along its entire length back to the tip of the rod 36 bent at an angle indicated by dashed line 38 in FIGS. 6 and 7 thus a corresponding self-adjusting counter tension, pressure, and force is internally exerted upon the neck .11 in opposition to the applied string tension for controlling and preventing excessive longitudinal distortion of the neck i 11 along the length of the fingerboard 37.

It is tobe understood, regardless of the method of bow and warp prevention, any neck may bow very slightly. in fact, any neck should be allowed to bow slightly to enable lower string clearance and reduce string rattle or hiss, as well known in the art. Thus by automatically self-adjusting warp and bow prevention means, it is meant any neck which automatically self-adjusts to compensate, counteract, and equalize string pull to thereby keep the instrument neck true to practical limits whereby the neck does not become bowed nor warped to the point of requiring excessive string clearance, thus not to be limited to an absolutely true instrument neck.

It is also to be understood and apparent that the present invention may be applied to semihollow body type, hollow body type, flat top type, arched type, accoustic type, electric type, as well as right-or left-handed instruments. Furthennore, it is also apparent that the instrument neck may be mounted to an instrument body countersunken in the instrument body as practiced in the art, that is mounting the neck to the instrument body in such a manner that only part of the neck extends above the surface of the top of the instrument body.

The foregoing is considered as illustrative of the principals of the invention, further, since numerous modifications and changes may readily occur, it is not desired to limit the invention to the exact construction and operation shown and described. Thus all suitable modifications and equivalents may be resorted to without falling beyond the scope of the present invention.

1 claim:

1. In a stringed musical instrument having connected to the instrument body, mg:

a neck height adjustment means mounted within' said body;

a truss rod loosely secured within a channel in'said neck;

and having one end terminating against said neck height adjustment means whereby said adjusting means and said truss rod are movable to vary the force acting agaihstsaid neck in order to prevent neck warping and bowing, and at the same time for controlling the height of said neck.

2. The invention specified in claim 1 wherein the neck height adjustment means comprises a threaded member threading into the instrument body.

3. The invention specified in claim 1 wherein said truss rod is bent near the end of said neck nearest the instrument bridge.

4. The invention specified in claim 3 wherein said truss rod is bent within a range from parallel to from parallel to the longitudinal axis of the fingerboard.

5. The invention specified in claim 1 wherein said truss rod is curved along its length.

6. The invention specified in claim 5 wherein said truss rod a neck pivotably the improvement comprisis bent along its length within a range from parallel to less than