US 2829728 A
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Description (OCR text may contain errors)
April 8, 1958 l. M. BROWN PROTECTIVE CONE ASSEMBLY FOR LOUD SPEAKERS Filed Nov, 9, 195
PROTECTIVE CONE ASSEMBLY FOR LOUD SPEAKERS Ilo M. Brown, Omaha, Nebn, assignor to The Ballantyne Company, Omaha, Nebr., a corporation of Nebraska Application November 9, 1956, Serial No. 621,238 2 Claims. c1. 131-31 This invention relates to loud speakers such as are used in out-of-door installations and particularly in open air moving picture theatres where the speakers are subjected to extreme weather conditions, and in particular this invention relates to protective cone elements spaced out wardly from, and in sealed relation with respect to the conventional cone of the speaker, whereby the conventional cone is protected and wherein the protective outer cone element is likewise protected and is easy to install in place of a damaged outer cone element.
A principal object of the present invention is to provide a novel and improved protective outer cone element to extend the life of cones of loud speakers in outside installations subjected to atmospheric conditions and possible damage from external sources.
- A further object of the invention is to provide a loud speaker unit for outside installations in which the cone thereof is protected from the weather with an outer shielding cone which can readily be removed and replaced in the field, thereby eliminating expensive repairs at places other than the place of installation.
A still'further object of the invention is to provide a loud speaker unit for outside installation in which the cone thereof is protected from the weather and from vandalism by an outer shielding cone and an outer perforated member of rigid sheet material, assembled into one unit to prevent the careless or intentional damage of the auxiliary cone by objects thrust through the outer grille of the loud speaker assembly.
In open air theatres where patrons are distributed over a comparatively wide area it is customary to provide individual speakers on posts, and although these speakers are substantially enclosed in a housing, with a grille and louvers over the cone, the cone is subjected to moisture and temperature changes whereby efi'icient operation of the speaker is limited to a comparatively short period of time.
Various attempts have been made to protect the paper cones in speakers for this use, such as stretching membranes across the base of the speaker. However, such expedients cause distortions in the sound produced, a loss of fidelity, and general lowering of efliciency. In accordance with U. S. Patent No. 2,670,807, to I. M. Brown, issued March 2, 1954, a speaker has been proposed which employs a paper cone therein enclosed in a housing and having an auxiliary protecting cone substantially of the same shape as the main paper cone, and spaced therefrom, the auxiliary cone being positioned in front of the main cone, whereby, with the space between the cones sealed and with the auxiliary cone having hinges and grooves corresponding with similar elements of the main cone, the auxiliary protecting cone vibrates with the main cone, and substantially the same sound waves are emitted therefrom.
One purpose of the present invention, therefore, is to provide improved means for protecting the main cone of a loud speaker from atmospheric conditions and United rates Patent O 2 vandalism without impairing the eifectiveness of the speaker.
A further purpose of the invention is to provide an improved protective auxiliary cone assembly for loud speaker units which may be readily removed and replaced.
Another purpose of the present invention is to provide an improved auxiliary protective'cone assembly for conventional cones of loud speaker units from changes in atmospheric conditions which may be installed in loud speaker units without materially changing the units and which is itself protected from damage by vandalism.
A still further purpose of the invention is to provide a loud speaker unit for outside installation in which the cone thereof is protected from the weather and from mechanical damage and which is of simple and economical construction.
Further objects, purposes and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings illustrative of a preferred embodiment wherein.
Figure 1 is a front elevational view of an improved auxiliary protective cone assembly for an outdoor loud speaker constructed in accordance with the present invention.
Figure 2 is a vertical, cross-sectional view taken on the line 2-2 of Figure l.
Figure 3 is a rear elevational view of the protective cone assembly of Figure l.
Figure 4 is a vertical cross-sectional view, with the main parts shown separated, of an outdoor loud speaker provided with an improved auxiliary protective cone assembly such as is illustrated in Figures 1, 2 and 3.
Referring to the drawings, 11 generally designates an outdoor loud speaker, com-prising the rear housing section 12, the front cover section 13, and the conventional driving unit 14, which is rigidly secured, in any suitable manner, to the wall of the rear housing section 12. The driving unit 14 includes the main paper cone 15 provided with the spherically curved, outwardly convex dust cap 16, secured centrally in the main cone, as shown in Figure 4. Main core 15 is formed with the annular. hinge 17 and with a plurality of annular corrugations 18 extending coaxially therewith. The frame of driving unit 14, shown at 19, includes the annular recessed rim flange 20 in which the outer peripheral portion of main cone 15 is secured and in which an annular sealing ring 21, of rubher, or other suitable resilient deformable material, is secured.
Designated generally at 22 is an auxiliary protective cone assembly adapted to be nestingly received in. the main cone 15 and being sealingly engageable at its peripheral portion with the sealing ring Zlt, and being spaced from main cone 15 thereby, said assembly 22 including an auxiliary paper cone element 23 which is positioned in spaced parallel relation to said main cone when the assembly 22 is nested therein. Qone element 23 is formed with an annular hinge 24 and with annular corrugations 25, similar to the hinge 17 and corrugations 1.3 of the main cone 15. Said cone element 23 is centrally formed with a spherically curved, rearwardly concave portion 26 similar in curvature to the dust cap 16 and being located in spaced parallel relation thereto when the assembly 22 is nested in main cone 15, as above described.
Front cover section 13 is formed with a circular recess 27 adapted to receive the peripheral portion of the assembly 22 and is adapted to be secured to rear housing section 12 by means of any suitable fastenings, whereby to clamp the peripheral portion of the assembly 22 against the deformable sealing ring 21. The front cover section 13 is formed with the horizontal slots 28 opening into the recess 27 and with the downwardly and outwardly sloping louvers 29 adjacent said slots, as shown in Figure 4. I
The peripheral edge of rear housing section 12 is recessed, as shown at 30 to receive a peripheral flange 31 provided on front cover section 13, to insure accurate registry of cover section 13 with rear housing section 12 and to provide a tight joint therebetween.
The lower portion of front cover section 1.3 is recessed, as shown at 32 to receive the knob 33 of a volume control potentiometer 34 mounted in the wall of the front cover section, as shown.
Referring now to Figures 1, 2 and 3, the auxiliary protective cone assembly 22 comprises a perforated disc 35 of rigid sheet material, such as aluminum or the like, the disc having its perforations, shown at 36, closely spaced and distributed uniformly thereover. The disc is inwardly offset at its central portion, as shown at 37, to improve its rigidity. The perforations 36 are relatively small, so as to effectively prevent the insertion of an object therethrough, and to thus protect the auxiliary cone 23 against mechanical damage through vandalism, but are sufiiciently closely spaced to allow free passage of sound waves therethrough without substantial impairment there of.
Disc 35 is formed with an annular forwardly facing peripheral seat 38 substantially of right-angular cross-sectional configuration in which is secured, in any suitable manner, as by the use of a suitable cement, a forwardly projecting sealing ring 39 of rubber or any other suitable resilient deformable material. The margin of the auxiliary paper cone element 23 is secured, by cement, or the like, to the rear surface of the peripheral seat 38, whereby the elements 23, 35 and 39 are fastened together and define the unitary assembly 22.
The assembly 22 may be readily replaced in the field whenever necessary by merely detaching front cover section 13 from rear housing section 12, which frees the as sembly 22 for removal, allowing a new auxiliary protective cone assembly to be substituted. Said assembly 22 may be also employed as a substitute for damaged auxiliary protective cones, such as employed in the above mentioned U. 5. Patent No. 2,670,807, without requiring any substantial modification of the main speaker housing components.
As will be apparent, by employing the improved auX- iliary cone assembly 22, as above described, the main cone 15 of the speaker driving unit 14 is protected against the effects of adverse atmospheric conditions, and both the auxiliary cone element 23 and said main cone 15 are protected against mechanical damage from vandalism.
While a specific embodiment of an improved outdoor loud speaker assembly has been disclosed in the foregogoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art.
Therefore, it is intended that 4 no limitations be placed on the invention except as defined by the scope of the appended claims.
What is claimed is:
1. An outdoor speaker comprising interlocking concave front and rear housing segments, a driving assembly secured in said rear housing segment, said driving assembly comprising a frame, a field structure secured in said frame, a main paper cone secured in said frame coaxially with said field structure and having a voice coil secured centrally thereof cooperating with said field structure, an outwardly convex dust cap secured centrally in said main cone, said main cone being formed with a plurality of annular corrugations extending coaxially therewith, an annular recessed rim flange on the frame, means securing the outer peripheral portion of the main cone in said rim flange, an annular resilient sealing ring secured in said rim flange over said outer peripheral portion of the main cone, an auxiliary protective cone assembly nestingly received in said main cone and sealingly engaging said sealing ring at its peripheral portion and'being spaced thereby from the main cone, said protective cone assembly comprising an auxiliary paper cone element positioned in spaced parallel relation to said main cone and being formed with annular corrugations coaxial with the main cone and being centrally formed with a spherically curved rearwardly concave portion similar in curvature with and located in spaced parallel relation to said dust cap, a perforated disc of rigid sheet material formed with an annular forwardly facing peripheral seat substantially of right angular cross section, means securing the peripheral portion of said auxiliary paper cone to the rear surface of said peripheral seat, and a forwardly projecting resilient sealing ring secured in said seat, said front housing segment being formed on its inside wall surface with a circular recess receiving said foiwardly projecting last named resilient sealing ring and being formed with sound transmitting apertures opening into said circular recess.
2. The structure of claim 1, and wherein said perforated disc of rigid sheet material comprises a relatively thin sheet metal disc having closely spaced relatively small perforations distributed uniformly thereover, the disc being inwardly offset at its central portion.
References Cited in the file of this patent UNITED STATES PATENTS 2,346,226 Marlow Apr. 11, 1944 2,483,317 Laurent Sept. 27, 1949 2,670,807 Brown Mar. 21, 1954 2,718,931 Boudouris Sept. 27, 1955 2,761,912 Touger et al Sept. 4, 1956 FOREIGN PATENTS 143,160 Australia Sept. 3, 1951