US 2477698 A
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2, 1949- G. w. LITTLE- 2,477,698
MICROPHONE MOUNTING FOR HEARING AIDS Filed April 5, 1948 jig. J
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IO J g jizverzh" George WLiZZe ByAZZorzzeys Patented Aug. 2, 1949 STATES MronorHoNs MOUNTING son HEARING AIDS Application April 5, 1948, Serial No. 18,876
2 Claims. 1
My invention relates to hearing aids and, more particularly, to means for reducing or eliminating extraneous noises rom the microphone thereof.
It is common practice in the manufacture hearing aids to position the microphone behind a perforate grill section formed integrally with one of the side walls of the casing. Due to the fact that the casing is conventionally carried in the wearers pocket or on other portions of the body where it is subject to frictional engagement with the clothing of the wearer and other objects, extraneous noises arising from movement of the clothing over portions of the casing are picked up by the microphone and transferred to the ear of the wearer with a resultant noise disturbance which at times becomes very uncomfortable.
In accordance with my invention, I provide a grill member which is disassociated from the casing and insulated both from the casing and from the microphone. With this novel arrangement, noises picked up by the casing are not transmitted to the grill member and hence are not picked up by the microphone.
Another object of my invention is the provision of a structure which, while greatly reducing the noise factor, is no more expensive to manufacture than conventional models heretofore produced, which is durable in use, and which can be used to enhance the appearance of the instrument.
The above and still further objects and advantages of my invention will become apparent from the following detailed specification, appended claims, and attached drawings.
Referring to the drawings, wherein like char= acters indicate like parts throughout the several views:
Fig. 1 is a view in front elevation of a hearing aid casing incorporating my novel arrangement; and
Fig. 2 is an enlarged fragmentary section, taken substantially on the line 2-2 of Fig. 1.
Referring with greater particularity to the drawings, the numeral l indicates, in its entirety, a casing of a conventional hearing aid, preferably formed from synthetic resins or the like and comprising two matching shell-like front and rear sections 2 and 3 respectively. The front wall section 2 is provided intermediate its side edges and preferably above its longitudinal center with a circular opening :3. The obvious reason for positioning the opening 4 above the medial center of the front wall section 2 is so it extends above the top of a shallow pocket, such as a vest pocket in which the casing l is frequently carried by the wearer. conventionally housed within the casing i, together with other electronic apparatus not shown, is a microphone unit 5 of the type manufactured by Shure Brothers, Model HMS, and having therein the usual diaphragm ii. Terminals i, one of which is shown, project laterally from the microphone 5 and are adapted .to maize electrical contact with other electronic apparatus not shown. The microphone 5 is carried by a shallow cupa which maybe-made of any relatively soft flexible resilient material such as soft rubber. The closed end *9 of the cup 3 is adapted to abut the rear wallsection ii; and the annular side wall it of the cup '8 extends forwardly to a point where it has abutting engagement with the inner surface of the front wall section 2, as indicated at H. The front wall section 2 is provided with an axially inwardly projecting circumferential flange 12 which closely encompasses the annular side wall it of the cup 8 and maintains the same against lateral movement within the housing I. The inner surface of the front wall section 2 is counterbored concentric with the opening 4, as indicated at E3, to receive the extreme forward or open end Hi of the cup 8.
The inner surface of the annular wall II) is provided with channels I5 and IS in the former of which the microphone 5 is seated. It will be seen that a portion I 5' of one side wall of the channel it overlies the forward marginal edge of the microphone 5, whereby to prevent movement thereof in a direction outwardly of the cup. When the microphone is equipped with a flange l5, as shown in Fig. 2, the channel I5 is cut away as indicated at it" to contain said flange. Generally, the microphone is bottomed in the cup 8 so as to have abutting engagement with the closed end 9 thereof.
Seated in the groove or channel It is an anchoring flange ll of a perforate grill element it. It will be noted that the central portion of the grill element It is in the nature of a flat circular plate It axially offset from the anchoring flange ll, whereby to provide a tubular side wall 29 having therein circumferentially-extended slots or perforations 2!. The plate i=9 lies substantially in the plane of the front wall section 2 concentric with the circular opening 4 and radially inwardly spaced from the side edge thereof. The spacing between the grill element l 8 and the microphone 5 provides a relatively dead air chamber 22; and it will be seen by reference to Fig. 2 that the side edges of the opening 4 and the circular plate [9 are rounded to provide smooth contours.
The grill element 18 may be formed from any suitable material such as metal or synthetic resins. In either event, the plate portion [9 may be provided with decorative markings or designs which enhance the overall appearance of the instrument.
While I have disclosed a preferred embodiment of my invention, it will be understood that the same is capable of modification without departure from the spirit and scope of the invention as defined in the claims.
What I claim is:
1. In a hearing aid, a casing having front and rear wall sections, said front wall section having a circular opening therethrough, a rubber-like cup within said casing, the base of said cup being in contact with the rear wall of said casing and the open end thereof being in contact with the front wall section of said casing concentric with and adjacent to said circular opening, means limiting lateral movements of said cup within said casing, a microphone within said cup and inwardly spaced from the open end thereof, means limiting axial movements of said microphone in said cup, a radially inwardly opening groove in the side wall of said cup intermediate the microphone and the front wall section of the casing, and a perforate grill member having its peripheral edge seated in said cup, the central portion of said grill member being axially outwardly offset from the peripheral portion thereof and lying within the opening of the casing in spaced relation to the side edges thereof.
2. In a hearing aid, a casing having front andrear wall sections, a circular opening in one of said wall sections intermediate the side edges thereof, a rubber-like cup within said casing with its bottom end in contact with the other of saidwall sections and with its open end in contact with said one of said wall sections concentric with the opening therein, means limiting lateral movements of said cup within said casing, the inner wall of said cup being provided with a pair of axially-spaced circumferentially-extended channels, a microphone within said cup seated within the innermost of said channels, a circular grill element seated in the other of said channels in axially spaced relation to said microphone and said front wall section, said grill element comprising a circular plate in substantially the same plane as the outer surface of said one of said wall sections and concentric with the opening therein, an axially-projecting tubular perforate side wall, and an outwardly-projecting circumferential anchoring flange seated in said channel.
GEORGE W. LII'ILE.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,039,625 Blount May 5, 1936 2,148,347 Gray Feb. 21, 1939 2,323,136 Shapiro Aug. 17, 1943 2,417,153 Darr Mar. 11, 1947 2,436,346 Veneklasen Dec. 14, 1948