US1284036A - Instrument to aid the hearing. - Google Patents

Description

' C. ANDERSON 6% HM. RWZMEW.

INSTRUMENT T0 KID THE HEARING.-

APPLICATION FILED; NOV- Patented Nov. -5

CL ANDERSON, OF NEW YORK, N. Y.

AND FREDERICK M. RI'IZMER, OF WEST EN GLE- WOOJD, NEW JERSEY, ASSIGNORS '10 CARL ANDERSON ELECTRIC CORPORATION, OF

NEW YORK, N. Y. A CORPORATION.

INSTRUMENT r0 AID THE HEARING.

IEIOSO.

Specification of Letters Patent.

Patented Nov. 5, IOI.

To all whom it may concern: Be it known that we, CARL ANDEnsoN, a

citizen of the United States, and a resident of the city, county, and State of New York, and FREDERICK M. RITZMER, subject ofthe Emperor of Germany and an applicant for citizenship of the United States, and a resident of West Englewood, in the county of Bergen and State of New Jersey, have jointly invented new and useful Improvements in Instruments to Aid the Hearing, of which the following is a specification.

Our invention relates to instruments for aiding the hearing and it is of service to persons who are hard of hearingor partially deaf. The present improvements relate more particularly to the part of the apparatus which serves as the transmitter. While the present device is particularly useful when used as part of an apparatus for aiding the hearing of those who are partially deaf, nevertheless, the device may be used generally wherever a transmitter is required. I

The object of our invention is to provide an instrument of the class described which will be very sensitive to all sounds, which will transmit the sounds with clearness to the receiving instrument and which will cause the sounds to be reproduced much louder in the receiver than with apparatus heretofore used. a

Another advantage of the present device is that it may be readily adapted to suit the peculiarities of various forms and conditions of deafness so that each instrument may be fitted to the particular user to give the best results. In instruments for aiding the hearing the principal object is to make sounds audible to the user of the instrument and we have found that in difi'erent forms or conditions of deafness, there are individual peculiarities. tain cases the person will be better able to hear sounds of a given character or quality than others. The present device is adapted to be readily modified to suit the varying conditions.

The principal feature of our invention resides in the use of a vibratory member which we prefer to call the drum head and which is inclosed in the casing and disposed so that sound waves entering the casing strike 4 front member 2 and For instance, in oer by a screw this drum head and are reflected by the latter upon the diaphragm of the microphone. The drum head is arranged at the rear side of the casing and facing the microphone dia ahragm. Preferably, it is inclosed by t e casing so that there is a closed air space behind it. In the fullest embodiment of the invention we employ perforated plates between the drum head and the diaphragm, arranged in a novel manner as will be set 'forth hereinafter.

In the drawing forming plication,

Figure 1 is a front'elevation of the transmitting instrument which embodies the features of our invention,

Fig. 2 is a sectional view taken on the line 2-2 of Fig. 1,

Fig. 3 is a sectional view taken on the line 33 of Fig. 2, and

' Fig. 4: is an elevation of the microphone detached.

The outer shell or casing 1 comprises the a rear member 3, having, respectively, the front wall 4, the rear wall 5 and the telescoping flanges 6 and 7. This casing is adapted to contain the various parts of the transmitting instrument. When body the wall 5 faces the body and the wall 4 faces away therefromor in the general direction from which the sounds are likely to be received.

Withinthe casing 1 there is arranged the microphone and it is preferably placed so that the sound waves approach its diaphragm from the rear of the casing. Any sensitive microphone may be used in the device. The one shown herein comprises the casing member 8 which is attached to the part of this apfront wall 4 of the outer casing l by screws 9, and of a rear member 10, the members 8 and 10 having telescoping flanges 11, 12 secured together by a set screw 13. The carbon cup 14 is attached to the casing wall 8 15 and it has a number of recesses containing carbon balls 16. The lat ter rest against the diaphragm 17. The diaphragm is clamped against the end of the flange 11 and next to it there s placed a washer 18, then a plate 19 and then another washer 20. The plate 19 which we have arranged close to the diaphragm, is provided the instrument is carried upon the with a number of apertures 21 arranged near the outer edge, and the sound waves enter through these apertures just before reaching the diaphragm, So that they first reach the diaphragm at the edge and then move toward its center. The rear wall 10 of the microphone casing has a number of apertures 22 arranged in circles, and these apertures are nearer the axial line of the diaphragm than the apertures 21 of the plate 19. This arrangement of walls and apertures seems to add to the elearness of the instrument.

It will be understood that the carbon cup and the diaphragm connect in the usual manner with the plugs 23 With which the plug socket 24 may be connected. The wires 15 leading from the plug 24 are connected with any suitable battery and receiver, the latter instruments forming no part of our present invention and their use is well understood in the art.

The front wall 4 of the outer casing has apertures 26 arranged near its central portion and the sound waves enter through these apertures into the space 27 formed between the front wall 4 and the wall 8 of the microphone casing. The waves then pass through the annular space 28 between the inner and outer casings to the space 29 at the rear. From these they pass through the apertures 22 in the wall 10 and thence through the apertures 21 in the plate 19 and 'act on the diaphragm.

The member 30 which we call the drum head is clamped against a rear washer 31 by means of a front Washer 82 which fits snugly wit in the flange 7 and is driven tightly against the drum head. This arrangement forms a closed air space between the drum head 30 and the rear wall 5 of the outer casing. The drum head is thus inclosed and it can not come in contact with the person wearin the instrument or with other objects WhlCTl might arrest its vibrations in response to' the incoming sound waves and thus detract from its effect upon the diaphragm. In this arrangement the drum head will generally be much lighter and more resonant than the rear wall 5, so that it has a greater tendency to reflect the sound waves into the microphone. Its reflecting effect is also enhanced. by the closed air space 29 and by the wall5 which prevent the waves from passing right on through the rear of the instrument.

As abov pointed out, the sound waves entering the space 29 from the annular space 28 strike the drum head 30 and as the latter is very resonant these Waves are reflected with great energy through the opening in the wall 10 and plate 19 to the diaphragm. The drum head is a detachable and removable element, so that one may be removed and be replaced by another of different thickness or of different material. By altering the drum head it is possible to adapt the device for each individual case of deafness so that the instrument will be best adapted to the peculiar requirements. In some cases the hearing will be more sensitive to sound if a very thin drum head, say, for instance, one which is from four to ten thousandths of an inch thick, is used. In other cases a drum head up to one thirtysecond of an inch thick may be more suitable. Also, in some cases, better results may be obtained with a celluloid drum head whereas, in another case one of brass or some other metal may serve the purpose better. 'Diff'erent materials affect the quality of the sound and in some cases the' hearing may be more sensitive to one quality than another. Thus, the drum head not only improves the delicacy of the instrument but it serves as a ready means for adapting instruments to the peculiarities of different forms of deafness.

The more resonant the drum head is the greater will be its effect in reflecting the sound waves to the diaphragm. In most cases it will be thinner and more resonant than the casing and it will require the protection of the casing t prevent injury there to. It may be made of celluloid, aluminum, brass, zinc, wood, or any other suitable material.

The drum head used in conjunction with the microphone in the manner shown is of decided advantage in securing the results set forth above and furthermore, there will be no blasting in the receiving instrument even when the sounds originate close to the transmitting instrument and it thus eliminates the confusion of sounds generally )resent in instruments of this class. Th use of the wall 10 and the plate 19 in the manner hereinshown gives better results, though they are not absolutely necessary to the use of the drum head itself.

The disposition of the drum head is such that its resonance causes the sound waves to be reflected to the diaphragm and not back toward their source.

Having described our invention what we claim is:

1. A sound instrument comprising :1 casing having a perforated front wall, a microphone in said casing and spaced therefrom to form a sound space around the microphone, said microphone having its diaphragm facing away from said perforated front wall of the casing, and a resonant member mounted in spaced relation to the rear wall of the casing and arranged to reflect the sound waves entering said sound space upon the diaphragm of said microphone.

2. A- sound instrument comprising a casing having a perforated front wall, a microraaaoac phone in said casing and spaced therefrom to form a sound space around the microphone, said microphone having its dia-' phragm facing away fromsaid perforated front wall of the casing, and a resonant member mounted in spaced relation to the rear wall of the casing and forming with the casing a sealed air space behind said resonant member, said resonant member being arranged t 'be acted upon by the sound waves entering said perforated front Wall of the casing and to reflect them upon the diaphragm of said microphone. I

3. A sound instrument comprising a casing having a perforated front wall, a micro phone in said casing and spaced therefrom t form a sound space around the microphone, said microphone having its diaphragm spaced away from said perforated front wall, a resonant member mounted in spaced relation to the rear wall of the easing and adapted to reflect the sound waves entering said sound space upon the diaphragm of said microphone and a perforated plate or wall interposed between said resonant member and Saul diaphragm;

4.- A sound instrument oomprislng a casing having a perforated front Wall, a microphone, said microphone having its dia hragm facing away fron said perforated ront Wall, aresonant member mounted in I spaced relation to the rear wall of the cas ing and adapted to reflect the sound waves entering said sound space upon the diaphragm of said microphone and a plurality of perforated plates or walls spaced apart and interposed between said resonant member and said diaphragm, the one nearest the diaphragm having apertures opposite the outer portion of the diaphragm and the. one farther from the diaphragm havingl apertures nearer the axial line of the diap ragm. Signed this seventh day of July, 1917.

CARL ANDERSON. FRED M. RITZMER.

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