US1722020A

US1722020A - Sound reproducer

Info

Publication number: US1722020A
Application number: US129733A
Authority: US
Inventors: Edwin H Smythe
Original assignee: Western Electric Co Inc
Current assignee: AT&T Corp
Priority date: 1926-08-17
Filing date: 1926-08-17
Publication date: 1929-07-23
Anticipated expiration: 1946-07-23

Description

July 23, 1929. E. H. SMYTHE SOUND REPRODUGER Filed Aug. 17, 1926 Patented July 23, 1929.

UNITED STATES. PATENT OFFICE.

EDWIN H. SMYTHE, EVANSTON, ILLINOIS, ASSIGNOR TO WESTERN ELECTRIC OOH-- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SOUND BEPBODUCEB.

Application filed August 17, 1926. Serial No. 129,783.

This invention relates to sound reproducers employing direct-acting diaphragms. The principal object of the inventon is to increase the energy imparted to the air from a sound radiating surface.

Another object of the invention is to increase the relative movement between stationary-and movable walls of a direct-acting sound reproducer.

The invention provides a sound reproducer comprising a movable wall and a stationary supporting wall which are so related that the entire surface of the movable wall is free to vibrate in response to sound variations. According to a feature of the invention, sub

stantially all the flexibility necessary to per mit the movable wall to vibrate as a whole for low frequencies is concentrated near the periphery of the structure and external to the movable 'wall.

In aspecific embodiment of the invention a conical diaphragm, which is driven at the apex, and a frusto-conical supporting member are connected base to base by means of an annular ring of extremely light flexible material, such as 'duralumin, having one or more peripheral corrugations. The'connecting ring, is rigid in the direction of the plane of the base of the diaphragm, but

is flexible in a direction perpendicular to the plane of the base of the diaphragm, and hence permits the diaphragm to move toward and away from the support in responseto sound vibrations, but prevents the diaphragm from moving laterally .with respect thereto, and also prevents the. radial relief of air pressures from the space enclosed be tween the relatively movingmember and the relatively stationary member.

ti0n,the bases of the conical diaphragm and frusto-conical supporting member are cemented directly together, and the required flexibility is obtained by cutting a series of slots close to the extreme outer edge of the supporting member.

The inventi Y will be described in connection with the accompanying drawing, in which similar reference'characters designate so similar parts in the different views, and in which: i

Fi 1 is aside view, partly in section, of a sound reproducer having a unilaterally flexible peripheral connection between the dia- 58 phragmand supporting member;

According to a modification of the inven-,

Fig. 2 is a fragmentary sectional view showmg a modified form of peripheral connections;

Fig. 3 is a perspective view showing a sound reproducer in which flexibility is obtained by cutting a series of slots adjacent the periphery of the supporting member; and

Fig. 4 is a fragmentary view showing a modified method of slotting the supporting member.

.The sound reproducer shown in Fig. 1 comprises a conical diaphragm 5 and a frusto-' V conical supporting member 6 which may be made of light stifi' material, such as blotting paper. The truncated end of the supporting member .6 is fastened securely to a suitable standard 7. The member 8 is provided for connecting a driving member to the apex of the conical diaphragm.

The connection between the diaphragm 5 and the supporting member 6 is provided by means of an annular ring 9 of extremely light flexible material, such as very light gauge duralumin, having a single deep peripheral corrugation 10. The connecting ring 9 is slightly larger in diameter than the diaphragm and supporting member and is joined on opposite sides-of the corrugation to the outer edges of the diaphragm and supporting member by means of cement 11. If desired, the connecting member 9 may be provided with a plurality of peripheral corrugations 12 as illustrated in Fig. 2.

.The connecting ring 9 may be formed in any suitable manner, such as by passing aflat strip of very light gauge duraluinin between properly shaped rollers adapted to form a channel of deeply corrugated cross-section and circular in form. This construction provides a pleated connecting ring which is inherently flexible across the plane of the corrugation, but is inherently rigid in the direction of the plane of the corrugation so that it will readily move in and out but will not buckle as the entire surface of the diaphragm 100 vibrates. i

In the modification of the invention illustrated in Fig. 3, the diaphragm and supporting member are cemented together base to base. The flexibility necessary to permit the 5 entire surface of the diaphragm to vibrate is provided by cutting a series of slots 13 disposed as closely as possible to the extreme outer edge of the frusto-conical supporting member, and preferably cut obliquely to 1m A I closure,

5 but further reducethe resistance offered by the connecting fingers of material to axial movement of the diaphragm. A strip of light flexible cloth 14 is pasted over the slots 13, in order to avoid any substantial air leakage through the slots. The'flexible cloth strip 14 may be pasted only along its inner and outer edges so that it will not increasethe transverse rigidity of the supporting membar in the zone that it covers. The shape and disposition of the slots adjacent the peripheral margin of the supporting member may be varied as desired to reduce the constraint of the supporting member upon the diaphragm for example, .being made triangular as illustrated in Fig. 4. 7,

Sound vibrations imparted to the apex of the conical diaphragm will tend to cause the entire surface of the diaphragm to vibrate as a unit and produce a greater relative movement between the surfaces of the diaphragm and supporting members' This produces a greater velocity of air movement into and out of the space between the diaphragm and supporting member and improves the respouse in the lower part of the musical scale.

The invention is also capable of other modifications and adaptations without departing from the scope and spirit of the invention as defined in the appended claims.

What is claimed is:

1. A sound reproducer comprising a directacting diaphragm and a supporting member forming a partial enclosure, and a unilateral- 11y flexible folded member connecting said iaphragm and said supporting member.

2. A sound reproducer comprising a directacting conical diaphragm and a supporting member forming a partial enclosure, and means including a V-shaped hinge joining the outer edges of said diaphragm and said supporting member to form a closure therebetween.

3. A sound reproducer comprising a conical diaphragm driven at the apex, a supporting member therefor forming a partial? en and a pleated member securedfto said diaphragm and said of'th flexible in a direction perpendicular to the plane of the base of'said diaphragm.

4:. A sound reproducer comprisingxa conical diaphragm driven at the apex,l.afrustoconical support for the. base offsaid diaphragm, and means including an annular pleated member of slightly, different outer diameter than the bases of the diaphragm and the support for connecting said support and sad diaphragm together.

ppert ng m era pleated member being rigid in'the direction e plane of the base-ofs'aid diaphragm @fa -c ndiment means for rigidly 's'upportinggsaidiap means providing a flexible connection. be-

tween said diaphragm and said support, saidmeans being positioned within the confines of the outer ed es of said diaphragm and said support and eing rigid in the direction parallel to the base of the diaphragm.

6. A sound reproducer comprising a conical diaphragm driven at the apex, a frustoconical support for the base of said diaphragm, the bases of said diaphragm and said support being substantially equal and spaced apart laterally and means for connecting the basesof said diaphragm and support comprising a member which is rigid in the direc tion of the plane of the base of said diaphragm and is flexible in a direction perpendicular to the plane of said base.

7. A sound reproducer comprising a conical diaphragm driven at the apex, a frustoconical support, the bases of said diaphra m and said support being spaced apart an a ring of extremely light resilient material connecting the outer edges of said diaphragm and support,

8. A sound reproducer comprising a conical diaphragm driven at the apex, a frustoconical support, and an annular ring of extremely light spring metal having a deep peripheral corrugation connecting the base of said diaphragm to the base of said support.

9. In a sound reproducing device, the combination of two dished members of equal base diameters, one of said members having an aperture therein, a link connecting the bases of said members together, said link being flexible in the direction of the axes of said members and rigid in the-direction perpendicular to the axes of said members, means for rigidly supporting one of said dished members at its aperture, and means connected to a point on the surfacefof th other of a dm rs. f m

thereto.

forte T noi i lar i mam bet, meansconnected to. spam for imparting vibrational forces thereto.

err-tad .f tits ape are, and 3.1115?- "the other of'said col o dal-shaped ineinbers In witness whereof,"I hereunto subscribe my name this 12 day of August A. D., 1926.

. EDWIN H.