US1808757A

US1808757A - Stringed musical instrument

Info

Publication number: US1808757A
Application number: US422337A
Authority: US
Inventors: George D Beauchamp
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-01-21
Filing date: 1930-01-21
Publication date: 1931-06-09
Anticipated expiration: 1948-06-09

Description

June 9, 1931.

e. D. BEAUCHAMP STRINGED MUSICAL INSTRUMENT Filed Jan. 21, 1930 2 Sheets- Sheet A TTORNE X8? June 9, 1931.

G. D. BEAUCHAMP 1,808,757

STRINGED MUSICAL INSTRUMENT Filed Jan. 21, 1930 2 Sheets-Sheet 2 a IN VEN OR.

A TTORNE Y Patented June 9, 1931 UNITED STATES PATENT OFFICE STBINGED MUSICAL INSTRUMENT Application filed January 21, 1930. Serial No. 422,337.

This invention relates to stringed musical instruments .embodyin thin metallic resonators ordiaphragms a apted tobe tensioned against or connected with the strings in such a manner that the vibrations set up in the strin s when the instrument is played will be su stantially amplified and the volume of the instrument increased.

'An'object of my invention is to provide in such an instrument an improved type of diaphragm so formed that a single large diaphragm may be employed in lieu of a plurality of smaller diaphragms. It will be understood that in instruments of the type mentioned the size of the diaphragms influences the quality and volume of the tones produced by the instruments. That is to say, that diaphragms of the character generally used which are conical in form and are con 2 nected with the strings at their apexes become inefficient as amplifiers or resonators as their diameters are increased beyond certain limits. In case diaphragms of excessive diameter are employed the vibrations which 26 emanate from the strings and are distributed to the diaphragms at their axes are dissipated before they reach the peripheries of the diaphragms. It is, however, desirable to provide in an instrument of the character mentioned a single diaphragm in lieu of a plurality of diaphragms for the reason that a single diaphragm lends itself to a more economical and simple construction.

Accordingly this invention comprehends 36 the provision of an improved form of diaphragm of relatively large diameter as compared to diaphragms usually employed in such instruments. My improved diaphragm 7 may be said to be generally of conical cross section, but includes a plurality of smaller conical portions or expressions integral with the main cone but having their axes arranged at points intermediate the axis and the periphery of the diaphragm. In this type of v construction the vibrations from the strings are communicated to the apexes of the smaller conical portions at points nearer the periphery of the main cone than would be possible were the strings connected with the apex of the main cone. Furthermore, there being a plurality of the conical expressions the vibrations from the strings are communicated at a plurality of points, preferably concentric with respect to the axis of the main cone, thus insuring a uniform distribution of the vibrations thruout the diaphragms.

This construction also provides clarity and quality of tone comparable with that obtained by the use of a plurality of separate diaphragms.

Another object is to provide an improved body structure for mounting the composite diaphragm in operative relation with the strings.

Other objects may appear in the description hereinafter following.

In the accompanying drawings I have shown a preferred form of my invention, in which Fig. 1 is a top plan view of an instrument embodying my improvements.

Fig. 2 is a transverse section of the same on line 22of Fig. 1.

Fig. 3 is a fragmentary section of the instrument on line 33 of Fig. 2.

Fig. i is an enlarged sectional plan of a diaphragm and supporting means therefor on line H of Fig. 2. v

Fig. 5 is a top plan View of a diaphragm.

Fig, 6 is a side elevation of the same.

The body of the instrument is preferably formed of thin sheet metal with the top 1 and bottom 2 substantially spaced apart and connected by a continuous side portion 3. A neck 4 and a tail piece 5 are suitably secured to opposite'ends of the body and serve to support a plurality of

strings

6, 6 etc., in tension over the top 1. The top of the body has a depressed central portion 7 integrally formed therewith and provided with an in- Wardly turned flange 8 at the bottom, thus forming a shallow compartment 9 at the top of the instrument, in which is held a single diaphragm 10.

The top 1 is counter-sunk at 11 at the upper side of the depression 7 so as to provide a seat for a plate 12 which closes the upper side of the compartment 9 and is attached to the body by means of screws or rivets 13.

i The plate 12 has a central aperture 14 and a internally: of the flange plurality of sets of apertures 15 therein thru which the tones of the instrument emanate. The diaphragm 10 is generally of conical cross section and has a peripheral flange 15 adapted to sea-t on the flange 8 of the body. One or more annular beads 16 may be formed 15 for rendering the diaphragm sufliciently flexible and. fmore. sensitive to vibrations th n would be possible Withoutthe beads. 1 4

The diaphragm 10 is supported onthe portion 7 at the top with its concave side downward and its convex side upward, and is formed with a plurality of conical portions 17, 1 T-etc concentriea ly arranged about the axis thereof. tersect the main cone of the diaphragm 10 and are positioned with theiraxesintermediate' the axis and theperiphery of the main cone. 'A spider 18 is mounted on the diaphragm 10 and is provided with a plurality of'arms 19, 19 etc., with

terminal portions

20, 20 etc., formedthereon which are adapted torest upon the. apexes oi the. portions 17. I may provide apertures at-the apeXes of thecportions 17 to .receive teats as at21, so

that the spider 18 will be incapable ofdis-- placement from operative. position'onthe diaphragm. .I prefer to arrange the spider 18 with two of the

arms

19, 19 in longitudinal alinement andthe other at right angles thereto, as shown inFig. 4, especially- Where three of the conical portions 17 are provided on the diaphragm. By this means I may groove the right angularly disposed arm 19 of the spider to receive a wooden-bridge 22-. Thus the spider 18 supports the bridge 22 in frictionalengagementwith the strings 6,

as shown in Fig. 3, and-the strings are tensioned over the bridge as'usual. f It will be noted that the bridge 22 extends upwardly thru the central opening 1 in the plate 12 and I provide a guard 23 formed. of flat strap metal which extends transversely over the strings6 and the opening-14 andis bent downwardly at its ends and 'fsuit ably secured] to the plate 1 The, guard 23' also serves as a hand rest-for the operatorwhenthe instrument-is being played. From the foregoingdescription of my invention, considered with the illustrations of the drawing, it will be apparentthat by communicating the vibrations from'the; strings 6 to the apeXes of the-conical portions17 inthe diaphragm 10, particularly at points 'outwardlyofthe axis of the diaphragm, the

vibrations-will more readily traverse the distances from the apexes of the-smaller cones to the outer periphery of the maincone than they would from the axis to the periphery of the main cone, and 1 substantially the same 7 quality of tone will be provided ina-single All diaphragm which would otherwise be provided in a multiple diaphragm. instrument.

The conical portions 17 iii-- The supporting portion 7 of the body has a large central aperture 24 therein so that body, and havingaplurality of portions at central points arranged to support said strings, ton-thepimpose. described;

v 2. A stringed. musical instrument: com-. prising. a body having s.ringsheldthereon .in tension,"a diaphragm. mounted in said. body;

and provided with apluralityof conically' formed portions, and meansengagingco1me+ sponding points of said portionsand alsoengaging said strings, :forthe purpose de-v scribedm v 3. A stringed musical/instrument;comprise. ing a body having stringsiheld thereon. in tension, a diaphragm. having. a plurality. of cones formed thereon and having-faxes intermediatethe axis. and. periphery otthe diaphragm, and means. intermediate the. axes .of

said cones andsaidstrings forcommunicating the vibrations from. the 'stringsx to the dia:

phragm.

4. A" strin edimusical?instrumenti incluch ing a body having stringsad-aptedto beheld in tension thereon, a. unitary V diaphragm formed'i'ot sheet metal supported; at its. periphery on said body and provided with a plurality of portions bent outwardly. from its periphery, and :mea'nsengaging saidoute wardlybentportionsand 'saidgstrings, for. the

purpose described I 5. A stringed musical instrument comprising a body having strings held in tension thereon, a metal chaphragm supported at. its periphery on said body and provided with a plurality of portions: bent outwardly from the planeofits periphery, and. common means engaging correspondingpoints on said outwardly-bent portions-- and engag ng said strings, forthepurpose described.

- 6.- In stringed mus-ical' instrument, 7 a metal d aphragmh-avlng a peripheral supporting flangeand a-plurality of outwardly bent=cones with axes concentric with theaxis of the diaphragm. V 7'; In a stringed musical instrument, adiaphragm in the form ot-a shallow'conehaving a peripheral supportingportion anda plurality of conical portions intersecting the main cone and arranged with thei-raXes concentric; with th'eaxis'oztthe main-cone. 8. Astringed musical instrument comprisin-ga body having its top bent-downwardly and inwardlyto provide a support,1a plate secured to the top of said body, strings held in tension over said plate, a diaphragm held at its periphery on said support and having a plurality of cones bent outwardly from the plane of the periphery of said diaphragm, and common means engaging corresponding portions of said cones and said strings, for the purpose described.

' 9. A stringed musical instrument comprising a body having its top bent downwardly and inwardly to provide a support, a plate secured to the top of said body, strings held in tension over said plate, a diaphragm held at its periphery on said support and having a plurality of cones bent outwardly from the plane of the periphery of said diaphragm, and common means engaging corresponding portions of said cones and said strings, said means including a spider in contact with the diaphragm, and a bridge intermediate said spider and said strings, for the purpose described.

10. A stringed musical instrument comprising a body having its top bent downwardly and inwardly to provide a support, a plate secured to the top of said body, strings held in tension over said plate, a diaphragm held at its periphery on said supportand havin a plurality of cones bent outwardly from t e plane of the periphery of said diaphragm, common means engaging corresponding portions of said cones and said strings, said means including a spider in contact with the diaphragm, a bridge intermediate said spider and said strings, said plate having an opening thru which said bridge extends, and a guard secured to said plate and overlying said strings.

GEORGE D; BEAUCHAMP.