US3435721A

US3435721A - Guitar construction

Info

Publication number: US3435721A
Application number: US579617A
Authority: US
Inventors: Rudolph Dopera
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-09-15
Filing date: 1966-09-15
Publication date: 1969-04-01
Anticipated expiration: 1986-04-01

Description

A ril 1, 1969 R. DOPERA GUITAR CONSTRUCTION Sheet of Filed Sept. 15. 1966 .rvm

N 1/5 N TOR R00 0L PH DOPERA BY EDWARD D. O'BR/AA/ Armin/5y April 1, 1969 RJDOPERA 3,435,721

. GUITAR CONSTRUCTION Filed'Sept. 15. 1966 Sheet 2 of 2 FIG. 3.

/ N VE/V 70E RuooL PH DOPE/2A EDWARD D. OER/AN I A770/QNEY United States Patent 3,435,721 GUITAR CONSTRUCTION Rudolph Dopera, 1045A Rosecrans Ave., Gardena, Calif. 90247 Filed Sept. 15, 1966, Ser. No. 579,617 Int. Cl. Gd 3/02 U.S. Cl. 84-296 4 Claims ABSTRACT OF THE DISCLOSURE A stringed musical instrument such as a guitar is disclosed which utilizes an internal polymer composition diaphragm as a support used for the strings used with the instrument. This diaphragm is domed and is provided with a flexed roll adjacent to its edge. The center of the dome of the diaphragm is thicker than the flex roll at the edge of the diaphragm.

Background Guitars are well-known string instruments, and ampliphonic guitars with conventional guitar bodies are known. In the past, however, the diaphragm within the body of an ampliphonic guitar was mounted on the guitar top. This required a large cover plate on the top of the guitar, which cover plate necessarily rendered a substantially different appearance to the guitar as compared to conventional construction. Except for these top mounted diaphragms, it has been necessary to use electronic amplification to provide the volume of tone desired beyond the volume obtainable from a conventional guitar. In conventional guitars, the entire top of the guitar body is intended for diaphragm action. However, since it is a structural member of the guitar, the top cannot fully act to produce the desired tone. Thus, it is desirable to provide a separate diaphragm which is particularly suited for transducing the signal from string vibration into air borne tone. The particular nature of the diaphragm and its mounting are critical factors in producing the proper and desired tone. Furthermore, while metal bodied string instruments have been known in the past, the particular three piece structure of the present guitar is admirably suited for use with the present diaphragm construction. The body construction comprises a top, a bottom, and a side band. Both the top and bottom end have flanges which are turned toward one another and the side band has slots for acceptance of these flanges. The flanges are secured into the slots in the manner consistent with the materials of the top, bottom, and side bands. This rigid construction has not been known in the past in stringed instruments of this nature.

Description Accordingly, it is an object of this invention to provide a guitar construction which is rigid and strong and in which the sound-producing structures are well protected so as to provide a guitar with long, trouble-free life. It is another object of this invention to provide a guitar construction wherein a diaphragm is mounted in a cylinder and the cylinder is mounted through an opening in the bottom of the guitar, the diaphragm carrying the bridge so that the diaphragm vibrates in accordance with string motion to produce excellent tone. It is a further object of this invention to provide a three piece guitar construction with top, bottom, and side bands firmly secured together. It is another object of this invention to provide a metallic guitar body wherein the top, bottom, and side bands are interrelated through flanges engaging in appropriate slots and secured therein for rigid construction. It is another object of this invention to provide a guitar bottom which is concave for com- 3,435,721 Patented Apr. 1, 1969 fortable support against the body of the musician. It is a further object of this invention to provide a bridge guard mounted upon the top, the bridge guard guarding the bridge and thus protecting the diaphragm against damage. Further objects and advantages of this invention will become apparent from a study of the following portion of this specification, the claims and the attached drawings.

FIG. 1 is a top plan view of the guitar construction of this invention.

FIG. 2 is an enlarged partial section taken generally along the line 2-2 of FIG. 1.

FIG. 3 is an enlarged partial section taken along the line 33 of FIG. 2.

FIG. 4 is an enlarged isometric view, with parts broken away, showing the details of interconnection between the top, side band, and bottom of the guitar as well as the place of entrance of the neck into the guitar body.

Referring to the drawings, the guitar construction of this invention is generally indicated by the guitar illustrated at 10. The guitar 10 has a body 12 and a neck 14. Body 12 is made up of top 16, bottom 18, and sides 20. Top 16, bottom 18, and sides 20 are made out of suitable material. This material may either be stainless steel or aluminum, or other materials. Except for slightly ditferent fabrication techniques, various materials may be interchangeably used in the guitar construction of this invention, but metal is preferred. Top 16 is of generally convex parabolic shape. It has S holes 22 and 24 to permit the escape of air vibrations from the interior of body 12 to provide exterior sound. Bridge opening 26 is also provided in top 16. Flange 28 is turned down around the edges of top 16. Top 16 may be formed by appropriate stamping and drawing steps.

Bottom 18 is similar to top 16 in that its plan outline is identical. However, bottom 18 is flat and has an upturned flange 30. Additionally, diaphragm cylinder opening 32 is provided in bottom 18. Opening 32 is preferably. circular in nature and is defined by circular recessed flange 34.

Sides 20 are preferably formed of extruded material having a flat outside surface 36. Sides 20 are thickened adjacent top and the

bottom edges

38 and 40 and provided with

slots

42 and 44 for the reception of

flanges

28 and 30. Since sides 20 are formed as a continuous extrusion, they are cut to length and are bent inward to provide

abutting panels

46 and 48. The extrusion is suitably contoured so as to match the shape of

flanges

28 and 30 and

panels

46 and 48 are secured together by suitable means such as spot welding or by adhesive. Similarly,

flanges

28 and 30 are respectively secured in

slots

42 and 44 by welding, soldering or adhesive means. Thus, the guitar body is formed.

Referring now to FIG. 2, it is seen that the diaphragm cylinder opening 32 is defined b circular recessed flange 34 which is inset above the bottom 18. Cylinder 50 is also formed of extruded material which is preferably turned into a hollow circular cylinder and secured in that form by overlapped edges. Cylinder 50 has an outward extending bottom flange 52 which fits into the recess of circular recessed flange 34. Cylinder 50 extends upwardly toward top 16 and has diaphragm flange 54 formed so as to extend inwardly just below the top edge of cylinder 50. A plurality of openings 56 are formed in the wall of cylinder 50 so as to permit communication from the interior of the cylinder to the exterior of the cylinder, still within body 12.

Neck openings

58 and 60 are also formed in the walls of cylinder 50 so as to permit a portion of the neck 14 to pass therethrough. Cylinder 50 is preferably formed of the same material from which top 16, bottom 18, and sides 20 are formed. Cylinder cover 62 is of such diameter as to fit within the recess formed by circular recessed flange 34, and is of such thickness as to lie, at its edges, flush with bottom 18. Screws 64 are engaged through cylinder cover 62 and bottom flange 52 into circular flange 34 so as to retain the entire structure in place. A suflicient number of screws 64 are used around the periphery of cover 62 to properly close the bottom end of cylinder 50. Cylinder cover 62 is preferabl concave so as to provide a concavity at this portion of the bottom of the guitar body. Such concavity is helpful in providing comfort to the user of the guitar as he holds it against his body. The material of cylinder cover 62 may either be that of the material of the other parts, or it may be of polymer composition material.

Diaphragm 66 is mounted upon diaphragm flange 54 to close the upper end of cylinder 50. Securement to the flange may be by any means which is consistent with the material. For example, when a polymer composition diaphragm 66 is used, it is preferably adhesively secured to flange 54. Diaprhagm 66 carries bridge base 68 at its center. Bridge base 68 extends through bridge opening 26. It is thus seen that vibration of bridge base 68 causes vibrational movement of diaphragm 66 to thus transduce the mechanical vibrations into sound energy. For best reproduction, the thickness and material combination of diaphragm 66 is critical. For fiberglass filled epoxy, or similar polymer composition materials, the dome of diaphragm 66, adjacent bridge base 68, is preferably about .060 inch. This decreases in the radially outward direction to a thin point of .010 inch at flex roll 70. From that point again, the thickness increases in the radial direction until it is of adequate thickness at diaphragm flange 54 for adequate support, preferably about .050 inch. Thus, there is substantial vibration of the entire dome of diaphragm 66 out to flex roll 70.

Referring now to FIG. 3, the diaphragm 66 and its bridge base 68 are shown in detail therein. Bridge base 68 is threaded at 72 and 74 for reception of screw posts 76 and 78. Screw posts 76 and 78 respectively carry

support flanges

80 and 82 upon which are mounted bridge 84. Bridge 84 has

suitable clearance openings

86 and 88 which accept the unthreaded upper ends of screw posts 76 and 78. Thus, by rotation of screw posts 76 and 78, which have screw driver slots accessible from the top, bridge 84 may be adjusted up and down. The bridge has conventional string notches in which the guitar strings are positioned. The mechanical energy introduced into the bridge by engagement of the strings in these notches cause vibration of the diaphragm and thus the production of sound.

Bridge guard 90 is mounted upon screws 92 and 94. Screws 92 and 94 are screwed into top 16 in appropriate position adjacent bridge opening 26. Bridge guard 90 is an appropriately shaped piece of material pivoted on screw 94 which passes through slot 95 in the end of the bridge guard. The other end of bridge guard 90 is secured by screw 94 which passes through slot 100, see FIG. 1, which is arranged so that when screws 92 and 94 are loosened, the bridge guard may be swung out of the way, and removed if desired, for adjustment of screw posts 76 and 78. However, when bridge guard 90 is swung into place and screws 92 and 94 are tightened it adequately protects bridge 84 and thus diaphragm 66.

Neck 14 is conventional construction. Neck 14 carries a fingerboard 102 which in turn has frets 104. Nut 106 has notches therein which act as string guides to hold the strings 108 at a proper height with respect to the fingerboard at the nut end, and to hold the strings in proper substantially parallel relationship to each other at the length of the fingerboard. Capstans 110 adjustably tighten strings so as to provide the proper tone, in accordance with the string weight, length between nut 106 and bridge 84 and tension. Of course the adjustable height of bridge 84 Provides for h pr p r clearance of the strings over the frets toward bridge 84.

Neck 14 also includes neck member 112 which extends into the opening interiorly of body 12 defined by

inturned flanges

114 and 116. These flanges are illustrated in FIG. 4 at the juncture of the ends of the side strip which form sides 20. Neck member 112 is preferably secured to these flanges so as to make a rigid neck connection with body 12. Neck member 112 is spaced from top 16 by means of wedge 118 which conforms to the shape of the top and provides a parallel bottom for adhesive securement to neck member 112. Neck member 112 further extends through

neck openings

58 and 60 in cylinder 50. Of course, upon assembly, wedge 118 and block 120 are first installed. Then, cylinder 50 is installed and this is followed by the installation of the neck member 112. The neck member 112 is appropriately clamped so that it can be glued, if desired, against wedge 118 and block 120. Screw 122 extends from the outside through block 120 and through cross dowell 124. This firmly secures the neck 14 in place and properly positions fingerboard 102 so that string 108 may be positioned in relation to it.

It is clear from the guitar construction described that a three piece guitar body is described. Of course, this construction is applicable to any stringed instrument of the type disclosed, and is not limited to guitars. The interlocking of the bottom and top with the sides provide excellent mechanical strength for long life whether the material is such that adhesive securing is necessary, or in.

the case where the material permits convenient soldering. This body has excellent acoustic properties, especially When the sound source is diaphragm 66 located within the body. The character of the diaphragm described is especially suitable for the production of the desired sound.

The character of the cylinder 50 and its installation through the guitar bottom also contributes to the ease of construction, the quality of sound rendition and the protection of the sound producing structure. This bottom mounted installation permits virtually continuous top, with only a small opening through which the bridge base extends. The adjustable bridge is thus easily protectable by a bridge guard supported upon the top. Of course, the adjustable bridge makes more quick and accurate string height adjustment with respect to frets 104. Openings 56 in the cylinder wall permit the sound waves within the cylinder to get into the main portion of the body, and the openings 56 provide proper modulation to produce the desired sound. The concave cover 62 provides an additional comfort and appearance factor.

While the bottom inserted resonant cylinder, which carries the diaphragm 66 on its top and bridge 84 on the top of the diaphragm, is described in connection with a guitar having a metallic body, it is clear that the bottom insertion of the cylinder, diaphragm and bridge is suitable on other types of guitar body constructions. For example, in a wood body guitar diaphragms have been known in the past. However, these previous diaphragms have been inserted from the top with the result that a large opening was required in the top of the guitar body. This was unsightly, unless covered by a large, decorative cover plate. In any event, it modified the appearance of the top of the guitar to an extent which some users considered to be unsatisfactory. The bottom inserted cylinder and diaphragm of this invention can just as readily be used on a wood body guitar to overcome these prior objections. Thus, the particular bottom inserted cylinder and diaphragm, carrying the bridge, can be used in any stringed instrument wherein the tone is produced by mechanical vibration, as contrasted to electronic amplified equipment.

This invention having been described in its preferred embodiment, it is clear that it is susceptible to numerous modifications and embodiments within the skill of the routine artisan and without the exercise of the inventive faculty.

I claim:

1. A stringed musical instrument which includes:

a hollow instrument body having a top and a bottom 6 and a centrally located hole positioned Within said 3. A stringed musical instrument as claimed in claim top, 1 including: a neck attached to said body so as to extend therefrom, a cylinder positioned within the interior .of said body, a plurality of strings attached to the extremity of said said cylinder extending from the bottom of said body neck remote from said body and to said body, said 5 towards the top of said body and being spaced from strings extending across said hole in the top of said the top of said body and body, wherein said edge of said diaphragm is mounted on the a diaphragm positioned within said body, extremity of said cylinder adjacent to said top of said diaphragm having a centrally-located dome, an said body.

edge and a flex roll separating said dome from said 4. A stringed musical instrument as claimed in claim 3 edge, wherein: said diaphragm being imperfO-rate, said polymer composition is a fiberglass composition. said diaphragm being formed of a polymer material, said diaphragm being thickest at the center of said dome References Cited and thinnest at said flex roll, 15 UNITED STATES PATENTS g gg g graiguauy decreasmg T thckness from 1, 9 ,434 2 1933 Dom/era 5 0 sa1 dome towards sald flex roll, 2 029 469 2/1936 D 84 296 the edge of said diaphragm being mounted within the 2045265 6/1936 Dopyera 84 292 interior of said body so that said dome and said flex 2905O42 9/1959 Hopyera roll are unsupported within the interior of said body, 20 oyer said dome projecting from said edge and said flex roll T R EFERENCES towards said top with the center of said dome being Valco Guitars, Inc. (advertising pamphlet), Dec. 7, located beneath said opening in said top, 1964; cover a e only,

a bridge mounted on the center of said dome, said bridge extending through said opening and en- 5 RICHARD WILKINSON, Primary Examinergaging said strings so as to pp said strings LAWRENCE R. FRANKLIN, Assistant Examiner. 2. A stringed musical instrument as claimed as in claim 1 wherein: US. Cl. X.R.

said polymer composition is a fiberglass composition. 8