US2390834A - Horn loud-speaker - Google Patents

Description

Dec. 11, 1945. J. HEGENER HORN. LOUDSPEAKER Filed Aug. 24, 1940 Patented Dec. 11, 1945 HORN LOUD-SPEAKER Joseph'flegener. Llanerch, Pa, assigns: to Radio Corporation of America, a corporation of Dela- Application August 24, 1940, Serial No. runs '7 Claims. (01. 181-27) cannon is close to the loudspeaker, have been known to travel back to the horn and to build up such an excessive pressure at the throat end thereof as to permanently deform and even break the diaphragm.

The primary object of my invention is to provide an improved horn structure for loudspeakers wherein the aforementioned danger is obviated.

More particularly, it is an object of my invention to provide an improved horn structure for loudspeakers wherein sound waves which may enter the horn from the atmosphere and build up an excessive pressure therein will be prevented from inJuring the diaphragm.

Another object of my invention is to provide an improved horn structure as aforesaid which is simple in construction and highly efllcient in use.

In accordance with my invention, I provide in the wall of a tubular horn an opening in proximity to the throat end of the horn and place a suitable, valve against the opening to normally close it under the influence of a spring or the like. The valve and its actuating spring are so constructed and arranged that, when sound waves traveling back through the born from the atmosphere build up an excessive pressure in the vicinity of the throat end thereof, the spring will yield in response to the excessive pressure and the valve will open to relieve this pressure and thus avoid injury to the diaphragm.

The novel features that I consider characteristic of my invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, as well as additional objects and advantages thereof will best be understood from the following description of one embodiment thereof, when read in connection with the accompanying drawing in which Figure l is a fragmentary view, partlyin section, of a horn incorporating one form of my invention.

Figure 2 is a plan view of the valve structure of this form of my invention, and

Figure 3 is a transverse sectional view through the throat end of a horn em dying another structure employing the principle of my invention.

Referring more particularly to the drawing, wherein similar reference numerals designate corresponding parts throughout, there is shown, in Fig. 1, a horn comprising an inner double-walled tubular member i cooperating with a reflector 3 to constitute a horn of more or less conventional type driven by a unit I which includes a suitable diaphragm 1. Adjacent the throat end of the tubular member I, there is provided a threaded opening 9 in the'inner wall is of the member I, a similar opening ll being formed in the outer wall lb of the member I in alignment with the opening 9. Into the opening 8 is threaded a short tubular member I! which may easily be inserted in place through the opening ii and which is formed with a shoulder i5 constituting a valve seat for a pair of cooperating flap valves l1 and I! which are hingedly carried on a pin 2i extending through the tubular member If. Wrapped around the central portion of the pin fl is a coil spring 23 which has its end 25 extending tangentially from the coil into engagement with the valve member l1, and its other end 21 extending tangentially from the coil into engagement with the valve member it.

Normally, the free ends I! and 21 of the coil spring 23, pressing against the valve members I! and I9, maintain the latter firmly closed,

against the valve seat I! to close off the opening 9. When, however, an excessive pressure is created in the vicinity of the throat end of the horn i, as by sound waves resulting from cannon fire, the pressure within the horn member I forces the valve member I! and I! away from the valve seat It against the action of the spring 13 to thereby open the opening 9 and permit escape of the air through the opening I I into the atmosphere to thereby relieve the pressure within the horn and thus prevent the excessive pressure from injury in the diaphragm 'i.

In the modification of my invention shown in Fig. 3. the inner wall In of the tubular member I is provided with a pair of openings 2! and Ila,

and the wall lb thereof is formed'with corre-.

spondingly aligned openings 3i and Ila, these openings corresponding, respectively, to the open. ings O and ii of the previously described modifi- 2 aaaassa 280. A coil spring 31 which is wound around the screw 33 and is interposed between the valve plate 35 and a washer or the like 39 on the screw 33 serves to normally maintain the valve plate 3! closed against the openings v2! and 29a. screw 33 may be threadedly adjusted on the tubular wall is through an opening I in the wall lb whereby to adjust the tension or the spring 31. The operation of the last described modification of my invention is similar to that shown in Fig. 1. When sound waves traveling down through the horn from the atmosphere build up an excessive pressure in the vicinity of the diaphragm, this pressure, acting against the valve plate 35. forces it away from the openings 23 and 2911 against the action of the spring 31. Thereupon, the compressed air passes out through the openings 29, 29a, and 3i, 3la, and the pressure at the throat and of the horn member is relieved. 4

Although I have shown and described but two embodiments of my invention, it will be apparent to those skilled in the art that many other modiflcations, as well as changes in those shown and described are possible. I, therefore, desire that my invention shall not be limited except insofar as is made necessary by the prior art and by the spirit of the appended claims.

I claim as my invention: I

1. An acoustical horn comprising a tubular member including a wall having an opening -therein, and yieldable means normally closing The.

said opening, said'means being yieldable in respouse to an excessive air pressure in the vicinity of said opening to permit escape of said air and thereby relieve said pressure.

2. An acoustical horn comprising a tubular member including a wall having an opening therein, and means at the exterior of said member normally closing said opening, said means being yieldable in a direction outwardly of said member in response to an excessive air pressure within said member in the vicinity of said opening to permit escape of said air and thereby relieve the pressure within said member.

3. An acoustical horn comprising a tubular member including a wall having an opening therein constituting a port, a valve movably associated with said port exteriorly of said member for movement into and out of closed relation with said port, and yieldable means normally holding said valve against said will over said opening whereby to close said port, said means being yieldable in response to an excessive air pressure within said member in the vicinity-or said opening to permit movement of said valve out of closed relation with said port whereby said. air may escape through saidport to relieve said pressure.

4. An acoustical horn comprising a tubular member including a wall having an opening therein constltuting a port, a valve movably asso. ciated with said port exteriorly or said member for movement into and out or closed relation .with said port, and a spring normally holding said valve against said wall over said opening to close said port, said spring being yieldable in response to an excessive air pressure within said member in the vicinity of said opening to permit movement of said valve out of closed relation with said port whereby said air may escape said port to relieve said pressure.

5. The invention set forth in 4 characterized in that said opening is located in proximity to the throat end 01' said member.

6. An acoustical horn comprising a tubular member including a wall having'an opening therein, a second tubular member fitted into said opening and extending outwardly of said horn,

. said second named member havinga shoulder constituting a valve seat formed adjacent its outer end, valve means associated with said valve seat, and yieldable means normally holding said valve means against said seat whereby to normally close said opening, said yieldable means being yieldable in responseto an excessive air pressure within said horn in the vicinity of said opening to permit movement of said valve means away-from said seat whereby said air may escape through said opening to release said pressure. I V

7. In a loudspeaker, the combination of a driver for generating acoustical vibrations, said driver including a vibratibl diaphragm, an acoustic amplifying horn coupled to said diaphragm and arranged to transmit to the atmosphere acoustical waves supplied thereto by said diaphragm, said horn including a wall-having an openingtherein in proximity to said diaphragm and constituting a port, a valve movably associated with said port exteriorly or said horn for movement into and out of closed relation with said port, and spring means normally holding said valve against said wall over said opening to close said port, said spring being yieldable in responsetoanairpressurewithinsaidhorn in the vicinity of said opening resulting from passage of acoustical waves from the atmosphere through said horn toward said dia- 'phragm to permit movement of said valve out of closed relation with said port when said air pressure reaches a magnitude greater than that which said diaphragm is capable oi delivering to said horn whereby said air may escape through said port to relieve said pressure and thereby prevent injury to said diaphragm.

- JOSEPH HEGENER.

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