US1708846A - Electrostatic telephone - Google Patents

Description

April 9, 1929. R. NAGEL ELECTROSTATIC TELEPHONE Filed May 9, 1928 Patented Apr. 9, 1929.

UNITED STATES PATENT OFFICE.

RICHARD NAGEL, OF SPAND'AU, GERMANY, ASSIGNOR TO F. AUGUST SGHROEDER, F

. NEW. YORK, N. Y.

ELECTROSTATIC TELEPHONE.

Application filed Ma 9, 1928, Serial No.

My invention relates to an electrostatic telephone and more particularly to a telephone of the stated type, the Ob]GCtS of which include the obtaining of high ei'liciency and reliability of operation, with a construction which is highly practical and which may be manufactured at a comparatively low cost.

Electrostatic telephones as hitherto constructed are provided, in order to comply with the above stated requirements, with strong, solid capacity bodies, such as castingswhich are worked and finished by means of special turning, grinding and polishing machines. Telephones or loud speakers constructed in this way necessarily have considerable weight and, therefore, cause inconvenience in moving them from place to place.

One object of my invention is to remedy this defect and with this object in view I provide, with the particular example of the invention here shown, in lieu of the heavy undivided capacity body hitherto used, a com posite body, made of sheet metal and composed of a plurality of individual units or members interconnected to form in their totality a rigid body of. the required shape and with an absolutely plain operating surface. The means I employ for the interconnecting purpose may be of various kinds such as clinchers, brackets, rings or similar fixtures.

In a preferred construction I employ sheet metal members or units of segmental shape which are to be interconnected only at their peripheral and central ends, while the radial edges thereof remain unconnected. Preferably I use for the purpose segmental sheets of a light metal or alloy of a thickness of approximately 1 millimetre and I provide perforations therein in the 'manner of a sieve. For reinforcin purposes I bend the free radial edges 0 the segmental members so that they form flanges projecting from the rear surface or side thereof, that is to say, the surface turned awa from the diaphragm, and constituting a re iable reinforcing means.

A construction adapted to be used in combination with the capacity body hereinbefore described, in general may comprise a wheellike body made of a light metal or alloy, and a preferably metallic thin sheet or foil which is kept under tension while being placed upon the said wheel-like body in order to be firmly connected therewith. In one example 276,490, and in Germany April 28, 1926.

like body, as regards circumferential size, is

employed to overlie the diaphragm and the segmental members are placed uponsuch insulating ring so as to be supported peripherally by the rim portion of the wheel-like body and centrally by the hub portion thereof, with the insulating ring intermediate between the rim portion of the wheel-like body and the peripheral ends of the segmental members, and with an insulating disk between the hub portion of the same and the central ends of the segmental members, so that the assembled parts will be properly insulated.

All of the segmental members having been accurately assembled to form a closed circular grid on the wheel-like body, an annular insulating body of comparatively great thickness is to be placed over and upon the peripheral ends of the segmental members. The annular body is similar to the rim of the wheel-likebody, in diametrical respects, and

.both bodies are provided with registering holes for the reception of screws for firmly uniting the two bodies with the capacity grid and the diaphragm inclusive of the insulating means therebetween, the diaphragm thus being safely held in place to maintain the full of its tension previously imparted to it. The segmental members constituting the capacity body preferably may be of the same size and shape. It goes without saying, however, as to certain phases of-the invention that they may be made of different areas and given any different sizes as regards the angle formed by the two radial edges of each member, and the capacity body may be composed of any desired number of segmental members of the same size or of different sizes.

With the above recited objects and general purposes in view, the invention resides in. the novel features of construction and combinations of parts as set forth in the following specificatiomas particularlypointed out in the, appended claims and illustrated in the accompanying drawings, it beingunderstood that the right is reserved to embodiments other than those actually illustrated herein, to the full extent indicated by the general meaning of the terms in which the claims are ex ressed.

n the accompanying drawings, forming surface or grid-plate composed of a number of segmental members of like shape and size Figure 2 is a similar view of the same with all of the parts constituting thetelephone duly assembled, but partially broken away to expose underlying parts; Figure 3 is a sectional'view, the section being taken on the I line AB of Figure 1;

Figure 4xis a perspective view of one of the segmental members; Figure 5is a sectional view. with the section taken on the line G-D of Figure 4; and Figure 6 is a perspective view of one of the segments constituting the annular insulating body.

.Parts which are repeated in the severalfigures bear the same reference characters in each case.

Referring to Figure 1 the wheel-like body 10 preferably made of a suitable aluminium alloy, comprises a rim 11, spokes 12 and a hub 13 having a threaded central bore 14 for the reception of a screw. The thin metallic sheetor foil constituting-the diaphragm 15 is supported by the wheel 10 and afiixed thereto while being kept under suitable tension.

The segmental members 16 to be mounted over and upon the diaphragm 15 in parallel relationship thereto, are made of a suitable sheet metal such as an aluminium alloy, and are provided throughout the whole area between the turned-up-radial edges or flanges 18 with smallholes or perforations '17 of circular or any, other appropriate form, while the peripheral ends 19 and the central ends 20 of the segm'ntal'meinbers 16 are preferably not perforated, aswill be seen in Figure 4;. 1

The area 19 forming the larger peripheral end of each segmental member 16 may be provided with two holes 21 and 22, a lateral nose or lug 24: on one side and a correspondingly shaped recess 23 on the other side for the reception of the lugof the adjacent memher when the members are duly assembled to form a circular body. In thisway the assemblage of the members'16 to constitute the latter may be effected in a ready manner and any unintentional displacement of the members with relation to each other during the assembling and mounting operations is prevented.

Inserted between the wheel 10 and the segmental members 16 is an insulating sheet or membrane 25 which has two holes 26 corresponding, as regards location to the holes fornse in connection with an electrostatic telephone having a capacity 21 and 22 of the'area 19. Instead of a membrane such as 25, any other insulating members or even an insulating ring of appropriate shape and size to conform to the rim 11 of the wheel, may be emplo ed.

The smaller central en s 20 of the segmental members 16 are supported by the hub 13 of the wheel 10 and a suitable insulating member may likewise be interposed between the ends 20 and the hub 13. This insulating member may be the sheet or membrane 25 or else a separate insulating means such as a small disk or the like or both may be used 'for the purpose in View.

When the parts so far described are properly assembled, they are to be interconnected in the following manner in order to constitute a rigidly framed structure. I place a rubber ring or washer 27 on the central part of the capacity grid so that the ends 20 of the segmental members 16 will lie between the washer 27 and the hub 13 of the wheel 10, as clearly shown in Figure 3, and

on top of the washer 27 I place a metallic disk 28 having a central bore for the accommodation of a screw 29, whereupon I firmly connect the disk 28 with the hub 13 by means of the-screw 29 engaging in the threaded bore 14 of the hub.

When the parts thus have been rigidl connected at the centre of the tele hone roceed to firmly unite the same at t e eri ery by mounting an annular body of insu ating material on the rim 11 of the wheel with the parts 16, 25 and 16lying between the wheel plurality of members of sheet metal, and

means for assembling and interconnecting the said members to form a rigid structure.

2. An electrostatic telephone, comprising a diaphragm, a capacity body composed of segmental members of sheet metal arranged radiallyclose by each other, and means for interconnecting the said members to form a rigid structure.

3. An electrostatic tele hone, comprising a diaphragm, a capacit ody composed of segmental membersof eet metal arranged radially close to each other, and means for interconnectin the central smaller ends and the peripherafiargerends, respectively, with each other.

4. An electrostatic telepgone, comprising a diaphragm, a capacity dy composed of segmental members having lateral or radial flanges and assembled with their flanges close by each other, and means for interconnecting the said members to form a rigid structure.

5. An electrostatic telephone, comprising a vibratory diaphragm, a capacity body cooperating with said diaphragm including a plurality of pressed sheet metal members, each formed with struck-up portions extending in a direction away from the dia hragm for Iionsiring the relative rigidity of t e capacity 6. An electrostatic telephone comprising a diaphragm, a capacity bodycomposed .of a plurality of sectionsopposed to" said dia phragm, means for interconnecting said sections to form a relatively ri id structure, and means individual to each 0 said sections for clamping the opposed diaphragm area in re spect to said sections respectively.

7. An electrostatic telephone, comprising'a diaphragm, a capacity body composed o a plurality of sections opposed to said diaphragm, said sections being formed with interlocking lug portions and recesses, and

means for clamping said sections in respect to each other to form a relatively rigid structure.

8. An electrostatic telephone comprising a diaphragm including conductive means, a

capacity body composed of a plurality of sections respectively opposed to said diaphragm, and resilient means for clamping portions of said sections in respect to said dlaphragm.

9. An electrostatic telephone comprising a diaphragm including conductive means, a supporting frame member, a capacity body comprising a plurality of sections opposed to said diaphragm, and clamping means at the mid-portion of the diaphragm for interconnecting said members.

10. An electrostatic telephone construction comprising a cast frame member, a perforated metal capacity body having struckup portions strengthening the same, and a vibratory diaphragm clamped in respect to said frame to extend over and to cooperate with said capacity body.

11. An electrostatic telephone construction comprisin a conductive vibratory diaphragm e ement, a plurality of relatively rigid capacit elements opposed to said diaphragm, a rame structure, and common means for clamping said diaphragm and said capacity members in respect to said frame structure.

In testimony whereof I have signed my name to this specification.

RICHARD NAGEL.

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