US2490138A - Valved closure for sound passages - Google Patents

Description

aNvEqToR ALFRED H.KETTLER ATTORNEY Dec. 6, 1949 A. H. KETTLER VALVED CLOSURE FOR SOUND PASSAGES Filed om. so, 1948 Patented Dec. 6, 1949 2,490,133 VALVED CLOSURE FOR SOUND PASSAGES Alfred H. Kettler, Collingswood,

Radio Corporation of America,

Delaware N. 1., assignor to a corporation of Application October 30, 1948, Serial No. 57,476

Claims.

This invention relates to sound translating apparatus, and more particularly to a mechanical means for preventing the pick up of noise by sound-powered telephones.

Telephones oi the sound-powered type are particularly adapted for use in many military applications, such as on battleships, or in other locations where there is considerable ambient noise. The sound powered telephone, which is employed in a conventional telephone headset, is of the reversible type, that is, it operates as a transmitter as well as a receiver. It frequently becomes necessary for a listener to remove his headset and lay it down or hang it on a hook. Since the headset usually remains connected to the telephone system, undesirable noise is picked up by the transducers and transmitted into the system, thereby interfering considerably with the transmission of useful signals to other listeners using telephone receivers which are also connected into that system.

In some cases, attempts have been made to overcome introducing undesirable signals into the system by connecting a switch between the telephone receiver and its connection to the telephone system which permits the user to disconnect the sound-powered telephone from the systern when the telephone is not in use. However, the switch is not as positive a means of preventing noise from being fed into the system as would be desired, for, as in many cases, the user might leave his post and forget to disconnect the instrument from the line, thereby creating a condition which permits introducing undesirable noise into the system. It is, therefore, the primary object of this invention, to provide a positive, automatic, mechanical means for preventing the pick up of undesirable noise by soundpowered telephones when they are not being used, although remaining connected in the telephone system.

It is another object of the invention to provide a mechanical means for automatically closing the sound opening in a telephone receiver when the receiver is removed from a listeners head and use thereof is discontinued, although the receiver remains connected to the telephone system.

It is also an object of the invention to provide an improved means for preventing noise pick up by sound translatin devices as aforesaid which is simple in construction, highly efiicient in use, and economical of manufacture.

The casing of a sound-powered telephone which houses the sound translating apparatus is customarily provided with an opening through which sound waves generated by the translating apparatus can emerge from the casing and be heard by a listener when the telephone is held in proximity to the ear. For the purpose of preventing extraneous sounds from being heard by the listener, as well as to permit the instrument to be worn with comfort, a flexible ear cap is usually attached to the casing, such ear cap surrounding the casing opening.

In accordance with the present invention, a valve is provided for closing the casing opening when the telephone receiver is not in use, the valve being normally biased to a closed position The flexible ear cap is arranged to contact the valve so that, when external pressure is applied to the ear cap (as when the ear cap is placed against the ear), it will withdraw the valve sufficiently from the casing opening to provide a path or passage through which sounds can emerge.

The novel features that are considered characteristic of the invention, as well as additional objects and advantages thereof, will be understood better from the following detailed description when read in connection with the accompanying drawing, in which Figure l is a front elevation of a telephone unit .in accordance with my present invention,

Figure 2 is a cross section of the telephone unit shown in Figure 1, taken on the line 22, showing the valve in a closed position, and

Figure 3 is a fragmentary, sectional view similar to Figure 2 but showing the valve in an open or withdrawn position.

Referring more particularly to the drawing, wherein similar reference numerals are used to designate corresponding parts throughout, there is shown a sound-powered telephone unit I including a casing 3 havin a removable cover or front plate 5. A vibratory element or diaphragm l is shown mounted within the casing 3 in spaced relation to the front plate 5. Sound translating apparatus which may comprise an electromechanical converter 9 of any suitable kind is also mounted in the casing and is operatively connected to the diaphragm l by means of a drive rod iii, the diaphragm and converter being adapted to function in a manner well known in the art.

An aperture or opening it is centrally located in the front plate or cover 5 for the purpose of permitting sound waves generated by the vibratory member 1 to emerge from the casing When a listener uses the device or unit I as a telephone receiver, the front plate 5 is held against the car so that sound waves generated by the vibratory member will be transmitted directly to the auditory canal. For the purpose of providing an acoustic seal against extraneous noises, as well as providing comfort for the wearer, an ear cap or flexible member !3 is attached securely to the front plate 5 by any suitable means. The ear cap i3 is constituted of a soft, flexible material, such as sponge rubber, or

an equivalent thereof which is capable of conforming easily to the contour of the human car. A central opening l provided in the ear cap I3 is in registry with the casin opening H and tapers outwardly toward the peripheral edges of the ear cap, as best seen in Figure 2.

For the purpose of closing or sealing the casing opening ii, in order to prevent undesirable sound waves, which originate externally of the receiver I, from entering the casing 3 when the receiver is not in use, a valve or closure member 11 is provided. The valve comprises a cylindrical portion I 9 disposed within the opening ll, an inner, disc-like portion 2| disposed on one end of the cylindrical portion, and an outer, resilient or spring-biased, disc-like portion 23 disposed on the opposite end of the cylindrical portion. The cylindrical portion i9 has a diameter smaller than the diameter of the casing opening H and a length greater than the thickness of the casing front plate 5. The inner and outer disc-like portions 2!, 23 have diameters greater than that of the casing opening II. The outer disc 23 is provided around its periphery, With a plurality of tabs or finger-like parts 25 which are resilient and bias the valve [7 outwardly from the receiver I by exerting pressure against the external surface 26 of the front plate 5. Thus, the outer disc 23 forces the inner disc 2|, which is located inside of the casing 3, against the internal surface 28 of the front plate 5, thereby forming a closure or seal for the casing opening I I, as shown in Figure 2.

A plurality of apertures 21 are provided in the outer disc 23 for the purpose of permitting sound waves, to be transmitted to the ear cap opening i5 while the instrument is in use and the valve is in an open or withdrawn position, as shown in Figure 3, the arrows 29 designating the path of the sound waves.

In order to move the valve to an open position, the inner marginal portions 3| Of the ear cap [3 are in contact with the marginal portion 33 of the outer disc 23 and the spring fingers 25. When the telephone receiver is placed on the head of a listener, the ear cap I3 is placed in contact with the listeners ear. The head band (not shown), which supports the receiver, presses the receiver against the listeners ear with sufiicient force to press the ear cap l3 against the outer disc 23 thereby flexing the spring fingers 25 and pushing the valve i'i inwardly to an open position. When the receiver is removed from the listeners head, the valve l1, being spring "biased outwardly, will be returned to its normal, closed position.

It will, of course, be recognized by those persons skilled in the art, that the above-described telephone unit may be used as a microphone or sound-powered transmitter, as well as a receiver when used as a transmitter, the ear cap is pressed against the region of a user's face about his 7 mouth with suiflcient pressure to push the valve to an open position, thereby permitting sound waves from his mouth to enter the casing for actuating the diaphragm. In this case, the ear cap forms an effective seal against extraneous sounds when it is in contact with the users-face and prevents those sounds from entering the casing.

From the foregoing description, it will be apparent to those persons skilled in the art that'the invention provides a positive, automatic, mechanical means for preventing extraneous noises from entering the casing of a sound-powered telephone receiver when the receiver is not being used as such although it remains connected into a telephone system. Although there is illustrated and described but a single embodiment of the invention, it will be apparent to those skilled in the art thatother forms, as well as changes, are possible. Therefore, it is desired that the particular form of the invention described herein be considered merely as illustrative and not as limiting.

What is claimed is:

1. In an acoustic device, the combination of a casing having an opening for the passage of sound therethrough, a closure member movably mounted within said opening and normally biased to closing relation with said opening for preventing the passage of sound therethrough, and a flexible member having an opening in registry with said casing opening carried by said casing,

said flexible member being in contact with said closure member and being yieldable in response to external pressure for displacing said member from its said closed relation with said casing opening to thereby leave said casing opening open for the passage of sound waves therethrough.

2. The invention set forth in claim 1 characterized in that said closure member comprises a cylindrical portion disposed within said casing opening, an inner disc disposed within said casing and connected to one end of said cylindrical portion, and an outer disc on the opposite end of said cylindrical portion external to said casing, and further characterized in that said inner and outer discs have diameters greater than said casing opening.

3. The invention set forth in claim 2 characterized in that said outer disc includes a plurality of resilient tabs which are in contact with the exterior surface of said casing for biasing said closure member outwardly with respect to said casing and into said closed relation.

4. The invention set forth in claim 3 characterized in that said outer disc is also provided with a plurality of openings in registry with said ear cap opening for the passage of sound waves transmitted through said casing opening, and further characterized in that the inner marginal portion of said flexible member contacts said outer disc adjacent said resilient tabs.

5. Sound translating apparatus for use in contact with the human ear comprising a casing having an opening for the passage of sound through one side thereof, sound translating means mounted within said casing, closure means extending through said casing opening and biased to provide a closure for said opening when said apparatus is not in use, and a flexible ear cap carried by the exterior of said one casing side and having an opening in registry with said casing opening, said ear cap being in contact with said closure means for influencing said means away from said casing opening when said ear contacts and presses against said ear cap thereby to permit passage of sound through said casing opening.

ALFRED H. KETTLER.

. 'No references cited.

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