US2433250A - Loud-speaker - Google Patents

Description

Dec. 23; 1947.

C. T. WEIBLER LOUD-SPEAKER Filed Oct. 26, 1945 ar/etoh T h ez'b/er I wmt E Patented Dec. 23, 1947 LOUD-SPEAKER Carleton T. Weibler, St. Charles, Ill., assignor to Operadio Manufacturing 00., St. Charles, 111., a corporation of Illinois Application October 26, 1945, Serial No. 624,660

18 Claims.

This invention relates to a loud speaker and particularly to a loud speaker for use in exposed locations subject to wind pressures.

Loud speakers of the type having a conical diaphregm cannot be used where any wind may strike the diaphragm. Irrespective of the driving means for operating the diaphragm, the diaphragm itself is generally driven by vibrating the same along the cone axis with respect to a normal rest position. Where a speaker is disposed in a location subject to wind pressure, the great area presented by a cone diaphragm results in the diaphragm and driving means being forced away from the normal rest position.

Thus, as an example, in the case of a dynamic speaker having an annular air gap with a voice coil assembly therein, the voice currents cause the assembly to vibrate back and forth from its normal rest position. Depending upon the polarity of the voce currents, the movement of the assembly and diaphragm will either be in the forward or reverse direction from the rest position. If, by virtue of wind pressure, the diaphragm and voice coil assembly is forced to assume a different position as a rest position, then total or partial inoperativeness may result.

A further drawback to the use of a speaker in exposed locations subject to wind resides in the possible damage to which the diaphragm may be subjected by air-borne dust and grit. While weather-proofin diaphr gms is well known, nevertheless sharp particles of grit and sand blown by wind may'cause surface scratches in the diaphragm and expose the diaphragm inter or to undes rable weathering influences. In addition, the abrasive action of air-borne dust and sand may actually weaken the diaphragm to the pont where its characteristics are entirely d fferent from the normal desired characteristics and, in some instances, total destruction of the diaphragm as such may occur.

In accordance with the invention herein, a shielding means i provided for the cone diaphragm of a loud speaker. This shielding means is so designed as to protect the diaphragm against wind and air-borne dust. The shielding member has means associated therewith so designed that the coupling characteristics between the conicalv diaphragm and atmosphere are substantially un affected so that speaker performance in terms: of sound radiation and efficiency remain sub-- stantially unchanged.

The invention further provides means for pre venting any substantial change in air pressure. on the exposed diaphragm surface arising out of the action of any wind blowing against the shielding system. Thus, a structure embodying the invention guides the air so that smooth defiection occurs without an adverse efiect upon speaker erformance. Th guiding of the air is accomplished in such a manner that airborne dust and grit is centrifugally eliminated and prevented from reaching the diaphragm air space. The air space at the exposed diaphragm surface is thus ma ntained in a substantially static condition as far as any wind effects are concerned so that it may respond efiiciently to vibrations of the diaphragm.

A structure embodying the invention additionally provides convenient protection against rein andprevents any water from impinging directly on the diaphragm.

In its more general form, the invention provides an assembly which may be applied to or removed from the sneaker as a unit or which may be incorporated with the speaker to form a complete speaker unit which may be operated in exposed locations. The structure added to the speaker consists generally of a rig d bafile structure and enclosing air relief ring. The bafile structure as a whole has obverse and reverse faces, the two faces terminating in a generally c rcular mounting portion or rim. The bafile structure is preferably symmetrical with respect to an axis, this axis being co ncident with the diaphragm axis of the speaker in the normal use of the bafile structure. The baflle structure is so disposed that the reverse face is spaced in o posed relation from the d aphragm of the speaker. Thus, the obverse face of the battle structure may be seen from the front of the entire speaker including the baffle structure.

The baffle structure as a whole is of ri id material and has the reverse face shaped, in the general form of a cone gener lly congruent to the speaker cone with which it is to be used. The proiected area of the speaker diaphragm is pref erably equal to the projected area of the baffle structure. By proper design and shaping of the baille surfaces, air blowing toward the speaker diaphragm strikes the obverse bafile surface and is deflected toward the mounting portion, The

relief ring structure rovides a passage for such deflected air outwardly toward the atmosphere, the air stream path being generally straight enough so that dirt and dust deflected by the baffle will follow the air out of the speaker. I

In order to prevent aspiration of the air between the speaker diaphragm and reverse face of the bafiie structure, the relief ring is so designed as to provide for the creation of some back pressure. This back pressure is generated in an annular space and mainta ns a substantially constant air pressure on the diaphragm face under wide hanges in wind pressure.

The baffle structure itself may take on a wide variety of forms, and the relief ring may also take on a wide variety of forms. Ifhe two together are rigidly supported withrespect to each other and may form an assembly which may be added to a speaker as a unit or wh ch may be added separately to the speaker and all the parts rigidly maintained to form a stable structure.

For a more complete description .of the invention, reference will now be made to the drawings wherein an exemplary embodiment of the invention is shown, it being understood that the in.- vention itself is susceptible to many modifications.

Referrin to the drawing,

'Figure '1 is an elevation withparts broken-away of a speaker having an assembly embodying the invention attached thereto.

Figure 2 is a detail of the grille.

A 'bafile structure generally indicated by "numeral I and made of any suitable rigid-material such as stamped sheet metalhas generally conical reverse face H and wind deflecting obverse face [2. In its simplest form, bafile structure If) may consistof two sheet metal members l3 and 44 :having mounting rims J and respectively. Sheet metal member 3 may be shaped to provide reverse face H, while member l4 may be bulged out to form obverse face 12. While it is not necessary that obverse face 12 be convex, it is preferred to have such a shape to provide desirable wind deflecting action. In its simplest form, metal member 14 may be shaped to form a portion of a sphere so that obverse face l2 will have a spherical curvature.

Mounting rims l5 and I6 are preferably shaped so that they are flat and may be disposed against each other to form a mounting portion for the baffle structure. Gasket 11 may be disposed between the opposed faces of mounting rims l5 and 16 to provide an air-tight baffle structure. It is understood that the mounting portion for the entire structure may'be thicker if desired.

Annular relief ring I 9 i disposed around mounting rims l5 and I6 and spaced therefrom I to provide annular air space 28 between the inside of relief ring 19 and mounting portions l5 and I6. Annular relief ring I9 may be formed of sheet metal or any other solid material provided with a large number of apertures. It may also be formed of woven wire or the like. Relief ring 19 preferably'forms part of grille 22 extending over the front of the baffle structure, namely obverse face l2. Grille 22 may be formed of the sar ne material as relief ring IS. The grille is provided to prevent dirt, bugs and other relatively large gbiects from getting into the speaker struc: ture. Grille 22 may have any desired shape and ishere'shown as flat.

Spaced from but enclosing relief ring I9 is rain guard 23. This is formed of solid material such assheet metal and is disposed against the peripheral portion of grille 22. To prevent rattling, gasket 2 is disposedbetween the rain guard and grille. As'is clearly evident from the drawing,

rainguard-23 clears relief ring, !9 so that outside air may readily reach relief ring IS. Preferably rain guard 23 extends down to the bottom of relief fins '9- p guard 26 in the form of an annular ring Gil is provided, this guard having upstanding flange 27. The guard and flange are of solid material such as sheet metal with the flange disposed immediately against a portion of the relief ring.- As shown, flange 21 is inside of a part of relief ring l9 although the position may be reversed.

It will be noted that flange 21 has its free edge '28 so disposed with respect to the mounting rims of the bafll structurethat the portion of relief ring l9 which communicates with the atmosphere :is substantially in lateral alignment with the deflecting portion of the baflle structure. Any air deflected from obverse face l2 may, thereforer pass straight throughrelief ring 19.

The entire assembly may be maintained as a unit by suitable means disposed at circumferentially spaced points along mounting rims l5 and 16. As shown, clamping regions are provided, each one having eyelet 30 threaded through suitably aligned apertures in the gaskets, rain guard, grille and dripguard. To maintain the parts in the position shown, spacing sleeve .32 and 33may be provided on opposite sides of the baffle structure mounting portion. Gasket 34 may be disposed against drip guard 26, this gasket being on the outside of the bafile assembly. Gasket 34 thus presents an annular surface which may be considered a mounting surface for the entire -assembly.

The entire assembly may be secured-to a speaker by bolting the same. Thus, speaker 36 has annular mounting portion .31 against which gas.- ket 34 may be fitted. Annular mounting portion 37 is generally formed as a sheet metal spider or basket construction '38. Annular mounting portion 31 has secured thereto the large end of conical diaphragm 49. It is preferred to havereverse face ll generally congruent toconical diaphragm '40 with the two being substantially of equal size.

The distance between the assembly mounting portion determined by gasket 34 orring 2l,-if no gasket is used, and mounting rims l5 and I8 of the baffle structure will generally determine the spacing between opposed face .H and diaphragm 4D. The air-space thus formed, generally indicated by numeral 4|, terminates in a circumferential area 42 generally extending between the peripheral edges of face H and diaphragm 40. In general, area 42 may be considered as a cylindrical surface tangent to sleeves 32. 33. It is pre ferred to so proportion air space 4! that the opposed diaphragm and baille faces are generally parallel. It is also-preferred to so proportion air space d! that circumferential area 42 is substantially equal to the area of diaphragm 40. Thus, air waves generated by diaphragm 40 will tend to move out of the air space toward area 42 and the coupling between air space M and annular space 29 will be such as to minimize interference. From annular region 20, airwaves generated by diaphragm .40 continue around mounting rims l 5 and I6 of the baffle and pass through grill 22 to the front of the speaker. At a short distance away from the front of the entire speaker, it is found that the speaker characteristics with or without the baffle assembly remains substantially the same.

Conical diaphragm 40 differs somewhat from reverse face H at the small ends. Many speakers have dust cap 43. this generally having a spherical curvature. Dust cap. is part of voice coil assembly 44, this assembly, as is well known, providing a cylindrical voice coil. The voice coil assemblyoperatesin an annular 11.1.1 gap OI the usual magnetic structure. The magnetic structure may be either of the permanent or electromagnetic type, all of which are well known in the art.

The small end of conical diaphragm 40 is supported on corrugated disc 45 whose outer edge tainer.

It is evident that eyelets 30 may be omitted, and that the bafiie structure assembly may be added to the speaker as individual parts rather than as a complete assembly, and the whole speaker as such maintained rigid by bolts, eyelets or any other means.

It is clear that a baiile structure embodying the invention permits of speaker operation under wind conditions. Rain guard 23 may be omitted if desired. Similarly, grille 22 may be omitted. Wide variations and changes in mechanical details of the baflie structure, support and spacing means may be made without departing from the spirit of the invention.

What is claimed is:

1. An assembly for use with a conical diaphragm type of speaker for attachment thereto to permit speaker operation in exposed locations, said assembly comprising a baffle structure having obverse and reverse faces and a mounting portion all symmetrical with respect to an axis, said reverse face having a generally conical shape, an annular apertured member enclosing said structure at the mounting portion but spaced from said mounting portion to provide an annular air space, means for rigidly supporting said annular apertured member and baflle structure, said assembly being adapted to be disposed so that the axis of said baflie is coincident with the diaphragm axis and the reverse face is spaced from but opposed to said diaphragm, said bafile structure covering the entire diaphragm whereby air and dirt which would otherwise impinge on said diaphragm are deflected.

2. An assembly for use with a conical diaphragm type of speaker and adapted to be readily attached thereto to permit speaker operation in exposed locations, said assembly comprisin a bafile structure generally symmetrical to an axis coincident with the diaphragm axis when said assembly is disposed on a speaker, said baffle structure having a peripheral mounting portion and a generally conical reverse face and a wind deflecting obverse face, said two faces being symmetrical with respect to said axis, an annular member surrounding said baffle structure at the mounting portion, said annular member being spaced from said mounting portion to provide an annular air space, saidannular member bein apertured to provide air communication with the atmosphere and means for maintaining said annular member and baffle structure in assembled relation, said baffle structure when mounted being adapted to have said reverse face projecting inwardly toward said conical diaphragm and spaced therefrom.

3. An assembly for use with a conical diaphragm type of speaker and adapted to be readily attached thereto to permit speaker operation in exposed locations, said assembly comprising a baffle structure symmetrical with respect to an axis and having a circular mounting portion symmetrical with respect to said axis, said baflle structure having a reverse cone surface adapted to be disposed in proximity to a speaker diaphragm, said bailie structure having an obverse wind deflecting surface, an annular ring shaped member surrounding said mounting portion and spaced therefrom to form an annular air space between the two, a plurality of supporting means spaced along said mounting portion and engaging said annular ring for maintaining the two in assembled relation, the intervening space along said mounting portion between adjacent supporting means being otherwise clear, said annular member being apertured to provide air communication between said annular air space and outside atmosphere.

4. The structure of claim 3 wherein said annular apertured member has a portion thereof disposed over said obverse face of said baffle structure, said covering portion being apertured.

5. An assembly for use with a conical diaphragm type of speaker to permit operating the same in windy locations, said assembly comprising a baflle structure having a cone and baffle member each with a mounting rim, said bafile and cone bulging outwardly away from each other to provide obverse and reverse faces for said baille structure and having their rims sealed together, an annular apertured member disposed around said mounting rims and spaced therefrom to define an annular air space, said apertured member having a mounting portion lying in a plane parallel to the plane of said baffle structure mounting rims and laterally displaced therefrom on the baffle side, a mounting ring parallel to the mounting portion of said apertured member but on the other side of the mounting rims for said bafile structure, a plurality of spacing sleeves disposed at points spaced along the length of and on opposite sides of said baffle mounting rims and extending toward the mounting portion and mounting ring, and means passing through said sleeves for maintaining said assembly in rigid relation.

6. The structure of claim 5 wherein said apertured annular member has a portion also apertured and spaced from and over-lying the obverse space of said baffle structure.

7. An assembly for use with a conical diaphragm type of speaker to permit operating the same in windy locations, said assembly comprising a baffle structure having a cone and baffle member each with a mounting rim, said baiile and cone bulging outwardly away from each other to provide obverse and reverse faces for said baffle structure and having their rims sealed together, an annular apertured member disposed around said mounting rims and spaced therefrom to define an annular air space, said apertured member having a mounting portion lying in a plane parallel to said baffle structure mounting rims and laterally displaced therefrom on the baffle side of said rims, a mounting ring lying in a plane parallel to said mounting portion and disposed on the other side of said mounting rims, said mounting ring having a solid flange-like portion forming the outer wall of a portion of the annular air space on the cone side of the mounting rims, spacing means on opposite sides of said mounting rims and extending toward said mounting portion and mounting ring respective- 7 113 saidspacing means being localized ;at-;regions :spacedalong thesmountin rims soathat said annular airspace has substantiallyfree communication with the airon the two faces of said baflle structure, and means for maintaining said,

said apertured member is provided, said solid :memher having a mounting portion disposed to lieagainst the mounting portion of said apertured member.

10.,An assembly for use with a conical diaphragm type of speaker to permit operating the same in windy locations, said assembly comprising a bafile structure and having a cone and baflie member each with a mounting rim in a plane perpendicular to the cone axis, said baflle and .cone bulging outwardly away from each other :to provide obverse and reverse faces for said baflle structure :and having their rims disposed against each other, an annular apertured member disposed around said mounting rims and spaced therefrom to define an annular air space and having an apertured grille portion in front of said obverse face, said apertured member having a,

portion thereof forming a mounting portion lying in a plane parallel to the plane of said bafile mounting rims and laterally displaced therefrom on the bafiie side of said rims, a mounting ring lying in a plane parallel to said apertured mounting portion but on the other side of said mounting rims, said ring having an upstanding flange portion extending toward the plane of said mounting rims and terminating near said plane, said flange forming an enclosing wall for part of said annular air space, sleeves extending from said mounting rims on opposite sides toward said mounting portion and ring respectively, said sleeves being spaced circumferentially along said mounting rims, and means passing through said sleeves for maintaining the entire assembly in rigid relation.

11. The structure of claim 10 wherein-said last- ,named maintainingmeans comprises eyelets passing through said sleeves.

.12. A loud speaker comprising a conical diaphragm, a baffie structure for said diaphragm, said baffle structure having a conical reverse face and having an obverse face, means for mounting said baffle structure so that the reverse face is spaced from andsymmetrically disposed with respect to the outer diaphragm surface, an apertured enclosing member surrounding the edge of said ballie structure and spaced therefrom to define an annular air space joining the air spaces -'on the opposite faces of .said baffle structure, and means formaintaining said bafile structure, apertured member and cone diaphragm in assembled "relation.

v13. The structure of claim '12 wherein said cone face of said bafiie structure is generally congruent to said cone diaphragm and wherein the spacing between the two is so chosen that the transverse rain from entering into said side.

31882241213118 outer edge of the'airzspacebetween'the diaphragm and obverseface is substantially equal to the diaphragmarea.

14. A loud speaker including a cone diaphragm having a mounting rim at the large end .of the -.cone,1-a baffle-structure having a cone and a .baflle member disposed ;in back-to-back relation, said structurehaving amounting rim spaced from but overlying the mounting rim at the diaphragm, said bafiie structure having the cone spaced from .said diaphragm, an apertured member enclosing said baflle mounting rim but spaced therefrom to providean annular air space, said apertured member having a mounting portion over-lying the baffle mounting rim but spacedtherefrom on the 16. The structure of claim 14 wherein the spacing between the diaphragmand cone is such that .the peripheral area of this space is substantially equal to the area of the diaphragm.

1.7. Aloud speaker including-a cone diaphragm having a mounting rim at the large end of the cone, a baffle structure having a cone and baifle member each with a mounting rim in a plane perpendicular to the axis of the diaphragm, said bafiie and cone bulging outwardly away from each other to provide obverse and reverse faces respectively for said baffle structure and having their rims disposed against each other, the reverse face being opposite and spaced from said cone diaphragm, the spacing being such that the peripheral area is equal to the diaphragm area, an annular apertured member disposed around said mounting rims and spaced therefrom to define an annular air space, said apertured member having a portion thereof forming a mounting portion lying in a plane parallel to the plane of said ba-file mounting rims and laterally displaced therefrom on the baffle side of said rims, a mounting ring lying in a plane parallel to said apertured mounting portion but on the other side of said bafiie mounting rims, sleeves extending from said vbaiilemounting rims on opposite sides toward said mounting portion and ring respectively, said sleeves being spaced circumferentially along said mounting rims, said mounting ring being disposed against the mounting rim of the speaker, and means passing through said sleeves for main taining the entire assembly in rigid relation.

18. The structure of claim 17 wherein said mounting ring has an upstanding flange portion extending toward the plane of said baflie mounting rims and terminating near said plane, said flange forming an enclosing wall for part of said annular air space, and wherein a solid annular member is provided spaced from but enclosing said apertured member.

CARLE'ION T. WEIBLER.

Images