US1443371A - Sound box for phonographs - Google Patents

Description

Patented dan. 39, 1923.

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HENRY o. MARTIN, or nnxnanr, INDIANA.

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Application led January 23, 1922. Serial No. 531,232., l

To @ZZ whom t may `conce/rn.' 4 Be it known that l, HENRY C. Mnii'iiiy, a citizen of the United States of Anierica,,re

siding at Elkhart, in the countyof Elkhart? and State of indiana, have invented certain new and usefulV lmproveinents in Sound' Boxes for Phonographs, ot which the following is a specification.

The 4 present invention Vrelates particularly n to certain improvements in instruments oi' the phonograph type involving the sound conve Tinw members which include the conphragm of the 'sound box, and the tone arm `or tubular sound conveyer between the sound box andthe amplifying member 'or amplifier, together with other correlated improvements as will be hereinaiter niore'specifically pointed out and claimed. By the utilization of my invention sound conveying means are provided for accurately recording `and reproducing sounds or tones with fullv ymeasure and value that are clear and lifelike, and with the original full volume.

To this end the invention relates particularly to the construction of the sound conveying members, which are of increasing y conveying capacity, from the needle or stylus to the amplifier. `The thickness ot the inaterial of the walls of the conveyers also increases uniformly and gradually from the smaller end `of. the sound coiiveyer to the larger end, as will be `hereinafter specified and claimed.v i

,In the accompanying drawings l have illustrated one complete example of the physical yembodiment of my invention 'wherein the parts are combined and arranged according to thel best mode l have thus `far devised for the practical applica- ,tion of the principles of my invent-ion. n

Figure 1 is a top plan view, partly in section, of the adjustable, telescopic tone l the soundbox showing the diaphragm and,

the means of attaching, the conveyer arms thereto. i i

In the preferred form of the invention as y shown in the; drawings, the sound box des-- ignated as a' whole by the numerall is attached to the `tone armv and disposed at an angle to tlieplane ot the record disk cariiedcii the `turntable of the phonograph not shown, but which may be of suitable construction. V The angularly disposed sound'box thus travels' across the face ofthe disk in usual manner for recording and reproducing sounds. `ln yFigure l ity will be seen that the box includes ar metallic circular base lplate 2 havingan open center yfor attachment of the elbow or bend 3 of the tone arm el, andthe metallic elbow is fashioned with an exterior, annular vcollar ing head 6, there being interposed between the flange and head suitable non`-conduct `ing gaskets or rings 7. The plate, head, and

elbow are secured firmly together by means or screws passing through the flanged iead and the base plate as shown.

.or flange 5 to be encased within theretain- The diaphragm 9 oit' the sound boxis pret- 'erably of mica, and is of peculiar and novel construction. lt is in the form of a circular disk, concavo convex in shape with its vconcavity toward the reproducing or recording stylus, and its maximum thickness vat its radial center, adjacent to the opening in the elbow of the tone arm. The edges of the diaphragm decrease in' thickness toward the periphery there-of, and this formation, together with theconcavo-convex structure of the diaphragm, which is of `course resilient insures a movement of ythe sound vibrations or waves in a more conf centrated or central direction toward the outlet or opening of the sound box when recording,`and toward the inlet opening when reproducing, from whence thevibra tions or waves are distributed. The com paratively thin edges of the diaphragm are retainedpand secured to the base plate of the sound box, by a flanged retaining ring 10, and here also non-conducting gaskets,

ot rubber or other suitable material, are iny' terposed between the diaphragm and its re taining ring, vto prevent 'radiation of sound,V and the retaining ring is secured'to the underside of the base plate by screws 11.

Associated with the sound box are a multiplicity of sound conveying arms,.here inl vdicated as five in number and designated respectively 12, 13, le, 15, and 16, the arms increasing in capacity for conveying sound waves or vibrations. rllliese arms are of resilient metal, and formed into helical coils iio similar to springs, and the succeeding arms from 12 through 16 are composed of wire of increasing gauge and constitute successively heavier and less resilient conveyers, although all of the conveyer arms are resilientv tosome extent. The lower end of each of the arms, as indicated at 17 is brought to form an integral part of the stylus holder 18of usual form, and the needle19, which, because of the angular' position of the sound box,l is also disposed at an angle to the plane ofthe record, travels inthe groove usual, and is secured by the set screw 2O in the holder.y n A l The upper end of each of these conveyer arms, as 21, is secured in the diaphragm by means of upper and lower clamp nuts 22 and 23 as seen in Figure 4. The several conveyer arms are disposed about the center of the diaphragm, between the latter and the stylus holder, andare arranged symmetrically with ytheir respective upper and lower ends brought into close formation. The conveyer f arms differ, not only in the diameter of their 25 coils and gauge of thicknessv of the wire forming the coils, but they differ in length of wire between the stylus and the diaphragm and the wire may increase in thickness toward the stylus.

The Vconveying or transmitting arms lead ing from the stylus or needle to the diaphragm, where they are centrally located at the maximum thickness of the diaphragm insure a maximum force of vibrations on the diaphragm, thereby influencing the vibrations to greater action in their course of development and amplification in the tapered tone arm 4 forreproduction, and from the diaphragm to therecord in recording sounds. n

The tone arm 4 is also designed with this purpose in view, and is adjustable as to its length for adapting it to different conditions, thereby bringing the voice or sound to be recorded closer to the diaphragm and record, thus enhancing or increasing the force of the vibrations at the recording point, resulting in a deeper and clearer record produced by the needle.

As best seen in Figs. 1 and 2 the tone arm is a telescopic structure, and includes an inner tubular section 24 having a split end sleeve 25 with perforated ears 26, and a clamp screw 27 by means of which the sleeve, which embraces the upper end of the sound boxv elbow 3, is secured thereto in adjusted position for properly locating the sound box and needle on the record. The exterior, telescopictube orfsection 28 embraces the sec.-

tion 24 and isv movableuthereon, to extend or contract the length of the tone arm, there being sufficient frictional engagement betweenthe parts to hold thesections ofthe tube in adjusted location. The Vcross area, or interior diameter of the tone arm increases with its distance from the vsound box, and the material in, or the thickness of the walls of the tone arm also increases with the distancel from the sound box. The outer end of the tone arm is embraced by a sleeve 29 of the horizontally disposed elbow 30, the frictional contact between the sleeve and arm being vsuch as to hold the parts in proper relation, and a vertically disposed elbow 31 having an end sleeve 32 surrounds the reduced lextension 33 of the `horizontal elbow 30. The lower end 34 of the vertical elbow is encased within the larger sleeve 35 of the third elbow 36, and these three elbows, which form the connection between the tone arm proper and the amplifier", also have the ratio of their interior diameter, and the ratio of the thickness of their walls, increasedV with the distance from the sound box.

lBetween the tone arm above the record and the amplifier beneath the record, I employ a tone modifier, joining the ends ofthe divided amplifier and adapted to be extended or contracted in linear direction, to provide deeper or lower tones,l and lighter or higher tones respectively. Usually thisV re-V sult is accomplished in phonographs by increasing or diminishing the speed of the revolving Vor rotating record, and is objectionable for the reason that the tempo or time is unduly altered. By the utilization of my modifier, the tempo or time4 is not changed, although the tone is modified vas desired.

The structure employed inthe tone modiyfier involves the free end 37 ofthe elbow 36, a horizontallydisposed Ushape tubular member having legs 38 and 39, and the inf termediate bend 40, co-acting with 'sai'dend 37 and a complementary end 4l of the am plier, a portion of which isindicated as 42. In Figure 2 the modifier may be 'pulled outwardly or to the right to extend or elongate the amplifier at this point, or in similar manner, the modifier may be moved t'o its contracted position, as in the drawing, the tubes 38 and 39 sliding on the tubular ends 37 and 41. j

The gradual and uniform increase in the diameter of the conveyer or tone arm from the sound box through the tuning slide, and the corresponding thickness of the walls of the sound conveyer, assist in the development or amplication of the partials or fractions of sounds, before they reach the amplifier, and stimulate the action of the sound waves, thus rendering theirE production more facile.

It will be understood thatthe length of the vtone arm may be Aextended or 'contracted -through the relatively movable inner section 24 and outer section 28, and that the tone arm bodily. swings on the swivel joint 311-35 beneath the elbow 31, as usual.

Having thus fully described my invention, what I claim as new and desire to seof a sound box and stylus holder, of a plu-` CII rality of transmitting arms varying in length and composed of various but uniform thicknesses and eachhaving their respective ends connected with diaphragm and stylus holder. r

2. The combination with the diaphragm of a sound box and a stylus, of tone transmitting arms of dissimilar'degrees of resiliency, varying in length, and composed of various'but uniform thicknesses and each having their respective ends attached to said diaphragm and stylus.

l 3. The combination in a recording and reproducing instrument including the diaphragm and stylus, of a plurality of tone transmitting arms Varying in length and formed in helicaly coils of different diameters, each having its respective ends ateters and composed of various butuniformy thicknesses, and each said arm havingl its respective ends attached to said diaphragm and stylus. t t

In testimony whereof I aiiX my signature.

HENRY f CQ MARTIN.

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