US 3408461 A
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Description (OCR text may contain errors)
Oct. 29, 1968 B. G. LANGFORD HEARING AID Filed May 28, 1965 United States Patent O 3,408,461 HEARING AID Byron G. Langford, Phoenix, Ariz., assignor to Royal Industries, Inc., Pasadena, Calif., a corporation of California Filed May 28, 1965, Ser. No. 459,786 4 Claims. (Cl. 179-107) ABSTRACT F THE DISCLOSURE A sound coupling device for an ear mold of an electrical hearing aid, the device including a removable housing which carries an acoustic attenuator. The housing and attenuatorare readily removable as a unit for cleaning. A passage is provided to vent the ear canal of the user to outside air to avoid annoying pressure buildup within the ear.
This invention relates to a hearing aid and more particularly an improved ear mold comprising an integrated hearing aid.
Many different types of hearing aids are available to assist persons having hearing deliciencies. Such hearing aids typical-ly incorporate a microphone for converting sound waves to an electrical signal, an electronic amplifier for amplifying the signal, and a transducer for converting the amplied electrical signal into amplied sound waves which are directed through a passageway to the ear drum.
Miniaturization of electronic components and batteries has made possible the production of integrated hearing aids having all component parts incorporated in a single ear mold assembly worn in the ear. Integrated hearing aids are desirable because they are lightweight and convenient to use, and because they have the cosmetic advantage of being nconspicuous.
Because electronic components and batteries are disposed within the ear mold of an integrated hearings aid, the ear mold cannot be immersed in liquid for cleaning and removal of accumulated cerumen (ear wax) or other matter. Instead, the user must attempt to clean the ear mold with a pointed or probe-like instrument. Unfortunately, this often results in cerumen or other matter being pushed into the ear-mold passageway leading to the transducer.
Even partial blockage of the passageway is undesirable as it can markedly alter the amplilication and frequencyresponse characteristics of the hearing aid. Furthermore, attempts to clean the passageway may result in damage to the transducer.
Another problem encountered with conventional hearing aids is the buildup of a differential pressure between the outer atmosphere and the ear-canal region between the tightly fitted hearing aid and the ear drum. This pressure is a source of annoyance and possible discomfort to the user of the hearing aid. In the past, it has been necessary to provide a vent from the ear canal to the outside atmosphere by drilling a hole through the passageway which conducts sound waves from the transducer to the ear drum. This is a painstaking and expensive operation due to the limited space available and the many shape variations in custom-fitted ear molds.
A third problem with existing hearing aids is the lack of an inexpensive and standardized mounting for an acoustic attenuator between the transducer and the ear drum. Such attenuators are useful to control the frequency response of the hearing aid, and to avoid overdriving the ear drum as a result of louder-than-normal sounds.
The integrated ear mold hearing aid of the present invention includes a sound coupling device that overcomes all of these difficulties in a simple assembly which is 3,408,461 Patented Oct. 29, 1968 ice mounted in the portion of the hearing-aid ear mold which extends into the ear canal of the user. Provision is made for mounting the acoustic attenuator in a housing which is readily removed from the ear mold for cleaning. Cerumen and other matter is kept from entering the ear mold, accumulating instead on the removable housing where it can be easily removed. Means are provided to vent the ear canal to the outside atmosphere in a simple, inexpensive manner.
Briefly stated, the sound coupling device comprises a hollow shell having an open end and a closed end. The shell is secured to an ear mold of a hearing aid whereby the open end of the shell faces the inner ear and the closed end is sealed Within the ear mold. The closed end of the shell is provided with an opening which is in communication with a sound transducer disposed within the ear mold. A housing mounting an acoustic attenuator is releasably secured across the open end of the shell. In a preferred form, the closed end of the shell is provided with a second opening whereby the interior of the shell is vented to the ear mold interior. The attenuator may be provided with a screen secured to the housing, whereby the screen, housing and acoustic attenuator can be removed as a unit for cleaning.
The invention will be further described with reference to the attached drawings in which:
FIG. 1 is a View, partly broken away, of a hearing-aid ear mold mounted in an ear illustrating the hearing-aid electronics in dotted outline and incorporating the sound coupling device;
FIG. 2 is an enlarged cross sectional View of the detached sound coupling device of FIG. 1;
FIG. 3 is an end view of the detached sound coupling device, showing the end which faces the ear drum; and
FIG. 4 is a sectional view of the detached sound coupling device, taken on line 4 4 of F IG. 3.
Referring to FIG. l, the sound coupling device of this invention is shown as mounted in an integrated hearing aid 10 in which all hearing-aid components are mounted in a conventional ear mold 12. The ear mold is typically custom formed to assure a close, comfortable lit in the Wearers outer ear and ear canal. Disposed within the ear mold are a microphone 14, electronic amplier 15, battery 16 and sound transducer 17. These interconnected components may be of the conventional type and, for brevity, will not be described in detail.
A hollow extended portion 20 of the ear mold is tightly fitted into the outer part of an ear canal 21. A sound coupling device 23 is sealed Within the end of the hollow extended portion to be interposed between sound transducer 17 and the wearers ear drum (not shown). A tube 25 connects the sound transducer to the sound coupling device.
Referring to FIGS. 2 through 4, the sound coupling device includes a hollow shell 27 having an open end and a closed end. The closed end includes an opening 28 formed by a tubular extension 29 for interconnection with tube 2S. A housing 31 having an outwardly extending annular ange 32 is disposed within the shell, the ange abutting the open end of the shell. A screen 34 is secured to the flange, and a washer-like ring 36 is secured to the yscreen to lock it to the housing 31.
A central opening in ring 36 is preferably of approximately the same diameter as the inside diameter of the housing. The screen is preferably constructed of stainlesssteel wire. A satisfactory screen may be woven from approximately 0.0045-inch-diameter wire, the wire being spaced to produce substantially square openings of approximately 0.0055-inch side length.
The ange, screen and ring may be bonded together by cementing, soldering, or any other convenient means. The housing is removably secured within the shell by a male detent 38 in the shell and a female detent 39 in the housing, or by any other conventional means such as threads. If the housing and shell are threaded together, the ange can be slotted to engage a screwdriver for ease of removal.
The shell, housing, and ring may be constructed from metal or plastic. In a preferred form of the invention, these components are machined from Type 430F stainless steel.
An acoustic attenuator 41 is disposed within the housing between screen 34 and the closed end of shell 27. Acoustic attenuators, suitable for use in the sound coupling device are commercially available, and .may be obtained from Sintered Specialities Division, Panoramic Corp., 1405 Riverside St., Janesville, Wis. Models A- 308 through A-315 available from this manufacturer have, among others, proved suitable for use in the sound coupling device.
Shell 27 is permanently cemented in hollow extended portion 20 of the ear mold as shown in FIG. 1. The shell is allowed to project slightly from the end of the ear mold to form a recess 43 between the ear mold and ange 32 of the housing. When the ear mold is removed for cleaning, the housing, attenuator, screen and ring are easily withdrawn as a unit from the shell, the recess providing a convenient grip.
Any accumulations of cerumen or other matter within the ear canal are kept from entering the ear mold by the sound coupling device. These accumulations are easily removed by withdrawing the shell, attenuator, screen and ring assembly from the shell and submerging them in a cleaning solution.
In a preferred form of the invention, a second opening 45 is provided in the closed end of the shell. This opening serves to vent the sealed region of the ear canal to the outside atmosphere to compensate for changes in arnbient atmospheric pressure. In this form, the sound coupling device is used with a ventilated ear mold which has at least one opening from its outer surface to the hollow interior of the ear mold. Such openings are typically present around microphone 14 or, for example, around a hearing-aid volume control (not shown). The venting path is from the ear canal through screen 34, the porous acoustic attenuator, and opening 45, to the ventilated interior of the ear mold.
There has been described an improved integrated ear mold hearing aid including a sound coupling device which provides a mounting for an acoustic attenuator, an atmospheric vent for the ear canal, and a barrier to keep cerumen and other material from entering the interior of the ear mold. It is to be understood that the use of the sound coupling device is not restricted to integrated hearing aids in which all component parts of the hearing aid are located within the ear mold. For example, the invention also has utility in hearing aids having only the sound transducer mounted in the ear mold, the amplifier, battery, and microphone being located elsewhere on the wearers person.
1. In a hearing aid having an ear mold which houses a sound transducer for converting electrical signals into audible sounds, the ear mold having a hollow extended portion shaped to Iit sealingly within an ear canal, the extended portion having an open end spaced from the transducer and facing an ear drum of a user; an improved sound coupling device for transmitting sounds from the transducer into the ear canal, the device comprising:
a hollow housing releasably secured at the open end of the extended portion; an acoustic attenuator disposed in the housing whereby the housing and attenuator can be removed from the extended portion as a unit for cleaning; and
means coupled to the housing and to the sound transducer for transmitting sounds from the transducer to the attenuator.
2. The sound coupling device defined in claim 1 in whish said means comprises a hollow shell secured within the extended portion adjacent the open end thereof, the shell being shaped to receive the hollow housing in releasable engagement, the shell having an outer end facing away from the ear drum, and a tubing connected to the outer end of the shell and to the transducer to form a passageway for communicating sounds from the transducer to the interior of the shell.
3. The sound coupling device defined in claim 2 in which the housing has a flanged inner end facing the ear -drum and extending from the housing adjacent the open end of the extended portion, and further comprising a screen secured across the flanged inner end and extending over the acoustic attenuator.
4. The sound coupling device dened in claim 3 in which the ear mold is of the ventilated type having a passage permitting outside air to ow into the interior thereof, and in which the outer end of the shell has an opening communicating the interior of the ear mold and the acoustic attenuator.
References Cited UNITED STATES PATENTS 871,470 11/1907 Booth 179-182 2,874,231 2/1959 Wallace 179-107 2,939,923 6/1960 Henderson l79-182 3,126,977 3/1964 McGee 179-107 3,170,046 2/1965 Leale 179-107 KATHLEEN H. CLAFFY, Primary Examiner.
A. A. MCGILL, Assistant Examiner.