US1634292A

US1634292A - Art of the transmission of sound

Info

Publication number: US1634292A
Application number: US545293A
Authority: US
Inventors: Lederer Karl Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 1922-03-20
Filing date: 1922-03-20
Publication date: 1927-07-05
Anticipated expiration: 1944-07-05

Description

1927' K. M. LEDERER ART OF THE TRANSMISSION OF SOUND Filed March 20, 1922 2 Slants-Shae;v 1

mm ,0 a WW. m m. H

WITNESS E5 1927' K. M. LEDERER V ART OF THE TRANSMISSION OF SOUNQ Shoots-Sheet 2 Fil'qd March 20. 1922 Jhvehtor Witne ss I Patented July 5, 1927.

KARL mam LEDEBEE, F NEWARK, NEW JERSEY.

AM or rm: 'rnmsuissrou or scum Application fled latch 20, 1922. serial No. 545,898.

My. invention relates to the mechanical and electromagnetical-mechanical transmission of sound by means of a diaphragm as it prevails in phonographs, telephone receivers,

microphones and transmitters for ordinary as well as wireless telephony and the present invention has reference, more particularly, to a novel sound-transmisison device provided with a diaphragm which, due to its special construction and the material of which it is made is of extremelyIhi h elasticity and rigidity; and under ot erwise equal conditions, will transmit and reproducesounds more audibly than with the or- 16 dinary telephone diaphragm, since my novel diaphragm swings over a wider angle and therefore into motion a greater voiume of air. The invention is also adapted for use in producing original records for phono- 2 graphs, and the features above stated are also important in this respect.

When used for so-ca led telephone receivers with electromagnetic action, the diaphragm is provided a with a cone shaped armature which shall swin between correspondingly shaped cores form pole pieces) thereby permitting the diaphragm to swing over a wider angle than that of ordinary receivers.

Theconstruction is also such that there is a special path provided for the oscillating air, the conical armature acting as a valve or as piston in a pump, driving the air into the ear or other channels adapted for the reception, or transmission of the sound waves of such device as the megaphone and so called loud speakers and recording devices.

By the introduction of a stream of'air into the air chamber, formed by the case and diaphragm of the receiver, which stream of air, when desirable may be regulated in strength and which-stream of air must even tually pass throughthe only path left open for it, that is the opening in t e core around the cone of the diaphragm, the loudness of the sound shall be magnified stillfurther and possibly modulated.

This principle can readil be applied for phonographs and any simi ar 5 devices, which depend u on a diap ragm asan agency, but with neit er of the above-mew tioned apparatuses or devices is the throttling action of the cone on the diaph an absolute necessity/and where desirab e the cone may be omitted and a flat armature be applied.

With the various objects and purposes herein-above stated, the present invention consists, primarily, in the-novel sound-transmitting device hereinafter more fully set then finally embodied in the clauses of the v claims, which are appended to, and which form an essential part of the said specification.

The invention is illustrated in the accompan ing drawings, in which Figure 1 is a lan view of a diaphragm, showing one em odiment of the principles of the present invention; Figure 2 is a vertical section of the same; and Fi ure 3 is a vertical section of a-slightly mo ified. form of diaphragm.

Figure 4 is a transverse vertical section; Figure 5 a side elevation; and Figure 6 a plan view of a telephone receiver embracing the-novel features of the present invention Figure 7 is a vertical sectional representation of another design. of receiver or transmitter; and Figure 8 isa. side elevation of the same, with a portion of the device heing represented in section.

igures

9 and 10 are representations of other slightly modified forms of receivers; Figure 11 is a transverse vertical section of a double-acting loudvertical sectional 4 speaking receiver embodyin the principles of the present invention; an Figure 12 isa side elevation of the same.-

Similar'characters of reference are employed in all of the said above described views to indicate corresponding parts. Referring now more particularly to said Figures 1, 2 and 3, the numeral ,(1) represents the diaphragm disk, (2) thearmature, which, in all fi shape of a sing e or double cone, butwhich may also be only a plainpart of the diaphragm'or'which may in the'case of a nonma etic diaphragm consist of a magnetic dis or a flat ring. 7

The armature (2) may be part of the diares where visible, has the phragm as in upper part of Figure (2) or in upper part at lefthand side of the View in Figure (3); or itmay be staked in, as in lower part (2) in Figure (2) or it may be cemented, riveted. or screwed to the diaphragm as indicated in right hand side section of Figure (3).

The diaphragm is provided with an arrangement of annular grooves and ribs (3) which serve to increase flexibility and strength of the diaphragm. .The grooves and ribs (3) in Figure (2) are arranged symmetrically to the original plane of the diaphragm, while the grooves in Figure (3) are all on one side of the ori inal plane of the diaphragm. This latter -orm possesses certain advantages of manufacture. The

cross-section of such a diaphragm shall showor U shaped grooves or grooves of a sinusoidal character.

Wherever the diaphragm disk is an integral part of the path of the magnetic flux it must be of a magnetic material. In cases, however, where it is acting solely mechanlcally, the principal requirements are, high flexibility, durability and permanency. Besides the already well known materials used for this purpose such as steel, iron, mica, phosphor bronze, aluminum, aluminum alloys, etc., I may use hardened and properly tempered steel, cellon, celluloid and bakelite, condensite, and any other suitable compound or material capable of being moulded, pressed, machined or otherwise formed into the desired shape.

Referring now to Figure (4) the numerals (4), (4) indicate the two sections of pressed steel. or iron, connected to provide a suitable case which may serve either as a permanent magnet or as the yoke for an electromagnet. The joint 5-5, between the two sections of the case is preferably made in the form of annular bands folded over the two sections of the case for holding them together, the diaphragm (3) being suspended between the two sections of the case. The tubular core (6) of the electromagnet may either be solid or laminated (with laminations arranged in a spiralic tube) as indicated in Figures 4 and 11, or it may be drawn in the form of a tube as shown in Figures 9 and 10. p

This core is hollow so as to provide for an air path (7) and it is widened out towards the center of the diaphragm for reception of the armature 2.

The winding (8) of the electromagnet may either be wound on a light spool or may be made selfsupporting as shown in Figures 9, 10 and 11. One end of each of the cores in Figure (4) is screw threaded and the lower coreis held in lace by means of a suitable nut (10). This nut servesalso as an ear funnel, by means of which the sound waves are directed into the .ear. The u per core is screwed into an outlet (11) w ich carries a tubular extension '(12) by means of which acoustic connection may be established to the other ear, thereby providing a double acting phone. Numeral (9) indicates a washer which insulates the winding from the case and (13), (13) are binding posts for the electrical connection from the winding of the electromagnet to the external electrical circuit.

In the construction represented in

F igures

7 and 8 the joint (5), (5)" between the two sections of the case is made either by a tight fit or by screwing one section into the other. The lower case has arecess into which thediaphragm (3) is fitted. The upper section of case (4) has thashape of a cone and is increased in'height at the ex pense of the lower sectionas there is only one winding (8) used in said lower section being formed with an inwardly extending and suitably curved portion, as 17.

The tubular core (6) in Figure (7) has an extension (14) to which is secured by means of a collar (15) (which however could also be omitted) a horn or megaphone (16). The tubular core (6) as has been described in connection with the deviceshown in Fig ure (4), but it may be added that in Figure (6) the lower core is staked or screwed into the ear funnel (10). It is obvious that, when desirable, another megaphone, as 17, could be attached for the other side of the-diaphragm as indicated in Figures 11 and 12 of the drawings. If however only one megaphone is to be used and both sides of the diaphragm shall be utilized and connected to it, then acoustic connection has to be made so that said connections shall be in opposition, since there exists a phase difference of 180 degrees between the two sides of the diaphragm.

In the upper section of Figures (7) and 8) a nozzle (18) is shown through which a continuous-stream of gas (air) is passed whereby the sound is amplified, the action and purposes of which has been reviously stated. It is obvious that both sides of the receiver could be provided with such gas (air) amplifiers, as indicated in said Figures 11 and 12 of the drawings.

Referring now to the modification shown in Figure 7 of the drawings, the two

sections

4, 4 are held together by the screws or rivets 5, whereby the diaphragm is properly positioned and securely clamped in place.

This construction of the device differs from the device herein-before described, in that the core 6 is in the form of a tube, suitably widened at the. bottom for reception of the armature 2 therein. In its up er end,

the core is staked or spun into t e, case,

where it also carries a nozzle 21 with which, by means of a flexible tube, acoustic connection (which is not shown) may be established to the other ear. The lower section of the case 4 is caved in at 22 to perform the functions of an ordinary receiver of a head set. A short pole piece 11 also of a tubin is staked to the member 22 on the inner si e of the case; but the latter could also assume this function if it were drawn and spun out as will be evident.

Figure differs from Figure 9 only in the lower part of the case and the form of diaphra m applied. Only one view has been given 0% the modifications represented by Figures 9 and-10, as it is thought, that the other views with the rest of the ordinary details could readily be imagined. Figure 10,

represents a receiver transmitter with a sinle cone-shaped armature and one may speak into the lower section of the case 20, which approaches the form of a mouth piece of a transmitter and which is to be made preferably of metal, but which could naturally be made of composition. One could also receive messages at the upper end, when acoustic connection to one or both ears is established by means of flexible or semi-flexible tubes and earpieces. Itcan readily be imagined that such a receiver transmitter could be provided with bands, straps, etc.,

to be carried on the head by any telephone operator without being held in any way by the hand, as such is already done when separate nstruments are provided for trans -mitter and receiver. Contrary to the ordinary receiver, the receiver and receiver transmitter just described can successfully be operated over long and high resistance lines, as their windings consist of a great many turns over an iron core of substantial cross section-Wand an impedance (of several thousands of-"ohms-) which can readily be made congruent to the resistance, inductance and capacitance of long lines.

The improved diaphragm, when same is combined with the air amplifier can readily be used in the microphone of a phonograph, and similar devices, and the available motive power can be utilized to drive a small fan,

H turbine or bellows to furnish a continuous nected to the diaphragm of the receiver.

And a ain, reversing conditions, a hone, as just .cscribed, may be used for t e reproduction of phonograph records over long telephone lines or by means ofwireless telephony. Instead of using carbon microphones, or the like, I- use one or a number of receiver transmitters and then employ the well known means of transmission f or ordinary or wireless telephone,

And, goin one step further, I establish a direct mec ianical transmission of the motions of a needle or lever, following with one end the indentations of a (phonograph or gramophone, etc.) record, to the diaphragm of a receiver transmitter of the proper impedance and electrodynamic capacity, so that b the motions of the diaphragm, electrica currents are generated in the phone congruent to the motions of the diaphragm and the original soundways graphically imbedded in the record..

It is evident, that by the latter procedure, less distortion of sound and electrical current waves will result; because one step of the transformation is entirely eliminated, (the step from the diaphragm of the phonograph to the diaphragmof the microphone) and the process of reproduction, especially with regards to clearness, has been materially improved. In this respect (acoustically) the receiver is by far superior to the microphone, and last but not least, the whole energy setfree by the mechanically operated diaphragm of the phonograph receiver transmitter is available for the gen-. eration of electrical currents and the em ciency must therefore reach a maximum.

From the foregoing description it will be evident, that I have produced a diaphragm, made of any suitable material, such as celluloid, cellon, and of analogous material, or of metal, for uses in devices for the transmission of sound, and it is understood that such devices also include those for recording sound waves, devices for taking original' phonographic records, gramophones, and the like, and such other devices which serve more strictly in the transmission ofsounds, as in telephone receivers, transmitters, microphones, and the like.

I claim 1. A diaphragm for devices of the character specified comprising a disk-sha ed element provided with a cone-shape armature, and concentrically disposed annular grooves.

Q 2. A diaphragm for devices of the character specified comprising a disk-shaped element provided upon its opposite faces with cone-shaped armatures, and concentrically disposed annular grooves.

3. A diaphragm for devices of the character specified comprising a disk-shaped cle ment provided with a cone-shaped armature of magnetic material, and concentrically disposed annular grooves.

4. A diaphragm for devices of the character specified comprising a disk-shaped element provided upon its opposite faces with cone-sha ed armatu res of magnetic material, an concentrically disposed annular grooves.

5. In a device for the "transmission of sound, and similar apparatus, a diaphragm, associated with a tubular core, consisting of spirally wound= laminations, and a coil wound upon said core.

6. In a device for the transmission of sound, and similar apparatus, a diaphragm comprising a disk-shaped element provided with a cone-shaped armature, associated with a tubular core provided with a coneshaped opening fitted-over said armature, and a coil wound upon said core.

\ 7.1n a device for the transmission of sound,'and similar apparatus, a diaphragm comprising a disk-shaped element provided with a cone-shaped armature, associated with a tubular core consisting of spirally wound laminations and provided with a cone-shaped opening fitted over said armature, and a coil wound upon said core.

8.121 a device for the transmission of sound, and similar apparatus, a casing comprising a pair of sections, a diaphragm disposed between and held in place by said sections, means connected with said casing for admitting air into the-same, associated with a tubular" core, and a coil sound upon said core.

9. In a device for the transmission of sound, and similar apparatus, a casing comprising a pair of sections, a diaphragm disposed between and heldin place by said sections, means connected with said casing for admitting air into the same, a coneshaped armature associated with said diaphragm, a tubular core provided with a cone-shaped opening fitted over said armature, and a coil wound upon said core.

10. In a device for the transmission of sound, and similar apparatus, a casing comprising a pair of sections, a diaphragm disposed between and held in place by said sections, and each section being provided with an air-inlet for admission of a continuous stream of air into said casing and about the diaphragm.

11. In a device for the transmission of sound, and similar apparatus, a casing comprising a pair of sections, a diaphragm disposed between and held in place by said sections, and each section being provided with an air-inlet for admission of a continuous stream of air into said casing and about the diaphragm, associated with a tubular core, and a coil wound upon said core.

12. In a device for the transmission of sound, and similar apparatus, a casing comprising a pair of sections, a diaphragm disposed between and held in place by said sections, and each section being provided with an air-inlet for admission of a continuous stream of air into said casing and about the diaphragm, a cone-shaped armature associated with said diaphragm, a tubular cone provided with a cone-shaped opening fitted over said armature, and a coil wound upon said core.

In testimony whereof, I have subscribed my name.

KARL MARTIN LEDERER.