US2229206A - Audiometer - Google Patents

Description

Patented Jan. 21, 1941 came emiss- AUDIOMETER Joseph R. Cubert, Chicago, Ill., assignor to Aurex Corporation, Chicago, 111.,

nois

a corporation of Illi-' Application May 3, 1939, Serial no. 271,573

4 Claims.

This invention relates to audiometers for use in testing the hearing by means of an ear-piece held to the ear and in which a tone is produced by suitable means, and having a volume control by which the volume of -the said tone may be a reduced, to greater or less volume, until it can no longer be heard by the person whose hearing is being tested, and in which means are also provided for changing the pitch of said tone, so that the persons hearing may be tested for practically any note of the musical scale.

Generally stated, the object of the invention is to provide a novel and improved construction and arrangement whereby the said tone, at no matter what pitch or place in the musical scale, may be characterized by a tremolo effect, or other tremulus effect as a means of more accurately evaluating the hearing of the person whose ears are being tested, as it is found that some people can hear a. tone when it is unsteady, like a tremolo effect, when they would not be able to hear the same tone when the latter is continuous or steady, thereby to more accurately or more effectively test and evaluate the hearing of any person. It is also an object to provide certain novel details and features of construction and com binations tending to increase the general efliciency and desirability of an audiometer' of this particular character.

To the foregoing and other useful ends, the invention consists in matters hereinafter set forth andclaimed and shown in the accompanying drawings, in which- Fig. 1 is a front elevation of an audiometer embodying the principles of the invention.

Fig. 2 is a simple diagram showing the circuits thereof. I

Fig. 3 is a fragmentary or broken vertical longitudinal section, showing certain interior parts of the instrument.

Fig. 4 is a horizontal section on line 4-4 in Fig. 3 of the drawings.

As thus illustrated, the invention comprises a cabinet or housing I, with a front panel upon which the conti ols are located, as shown in Fig. 1 of the drawings.

In general, the audlometer shown is of a well known type, having the well known elements shown in Fig. 2 of the drawings, connected to the ear-piece 2, whichis placed to the ear to test the hearing, and the novelty is practically in the variable frequency oscillator 3 indicated in said diagram. This variable frequency oscillator comprises a condenser l which-is mounted in said cabinet or housing, in any suitable or desired. manner. The horizontal shaft 5 of this condenser is suitably mounted in bearings and has its front end provided with a knob 6 ,for the operation thereof by hand. In this way, the tone effective in the ear-piece to test the hearing of the person can range from the lower to the higher part of the musical scale, in order to vary the pitch of the tone and test the hearing for either high or low or intermediate notes of the scale.

As previously stated, it is found that a person may not hear a weak tone, when the latter is steady or continuous, but may be able to hear the same tone, without changing the volume thereof, when the tone is unsteady or oscillatory in character, like that of an ordinary tremolo effect in music. Therefore, to provide for such a tremolo effect in the ear-piece 2, as a matter of more accurately evaluating the hearing of the 'person, a motor 1 is provided and connected by a reduction gearing 8 with the shaftof a condenser 9 connected in shunt of the condenser 4 previously mentioned. With this arrangement, and with a switch Ill controlling said motor, a true tremolo effect is obtained, inasmuch as the pitch of the tone goes up and down, slightly, when the motor is running, but sufliciently to make it more audible, to some people, than practically the same tone when the latter is steady or continuous.

It is obvious, however, that the production of the tremolo effect can be accomplished in various ways, without departing from the spirit of the invention, for the purpose of more accurately evaluating the hearing, or the loss of hearing, of any. person whose hearing is being tested by th use of the audiometer instrument.

It is also obvious that the tone or sound in the ear-piece can be rendered unsteady, instead of continuous, in various ways, instead of .by using the ordinary tremolo effect, as by using what is known in music as a trill, or by using a rapid fluctuation of the volume, within limits approximating the limits of the variation of the pitch necesasry for a proper tremolo efiect, without departing from the spirit of the invention. In other words, an unsteady tone or sound suitable for the testing of the hearing, in the manner and for the purpose explained, may be produced by any suitable or desired means, in order to realize the fundamental and broader concepout that the term tremulous effect" or tremu lous sound effect as used in the present specification and claims is intended to cover the foregoing illustrative effects whether a so-called true tremolo eflect, a trill, or a relatively restricted periodic variation in volume. Inother words, the term tremulous effect as used herein is intended to cover tremolo and equivalent effects, whether produced by periodic variation in-pitch or intensity or both.

Obviously, the, so-called variable attenuator, which is a volume control, indicated at I I in Fig. 2 the drawings, can be of any suitable known or approved character and does not need any detail showing or description, as there are many well known volume controls that can be, and are, used for this purpose, and the same is true of the other common and well known elements of the instrument.

The purpose of the tremulous tone, in the earpiece, of course, is to make a tone audible, or more audible, which if steady would not be audible, or would be less audible.

What I claim as my invention is:

1. An audiometer comprising an ear piece for testing the hearing, means operatively connected to said ear piece for setting up in said ear piece sound of audible frequency, said last named means comprising an adjustable member for selectively varying the frequency of said sound to any of a plurality of fixed frequencies within the audible range, a manual control member connected to said adjustable member for manually rotating said member in any of said positions, volume control means operatively connected with said first named means for controlling the intento cause a predetermined relative minor variation sity of the sound, manual control means connected with said volumecontrol means and shiftable to rotate the volume control selectively in any of a series of positions corresponding to different sound intensities, and tremulous sound effect means operatively connected with said sound producing means, said last named means comprising a member shiftable through a predetermined path in tone characteristic, power operated means connected to said shiftable member and operable to periodically move said shiftable member in timed relation, and means for selectively controlling said power operated means.

2. In an audiometer, an ear piece for testing the hearing and comprising a converter for changing electrical vibrations to sound vibrations, an audiooscillator connected in electrical circuit with said ear piece and operable for causing sound vibrations, said audio-oscillator comprising means operatively connected therewith shiftable for selectively controlling the frequency set up by said oscillator, said last named means being shiftable to progressively control said frequency at any of a plurality of fixed audible frequencies and having manual control means connected therewith for rotating the shiftable means in any of said shifted positions, means in electrical circuit with said oscillator for controlling the amplitude of said vibrations, a manual control member connected therewith for independently determining said amplitude, tremulous effect means operatively associated with said circuit, said last named means comprising a member operatively associated with said oscillator circuit and movable through a limited predetermined path to vary the tone characteristic throughout a relatively restricted range, power operated means for shifting said movable member in periodic timed relation, and means for selectively operating said power operated means.

3. An audiometer as defined in claim 2, wherein said means for producing the tremulous eflect comprises a condenser connected in said audiooscillator circuit for periodically varying the pitch or volume within a relatively limited range.

4. An audiometer as defined in claim2, wherein said pitch control means comprises a variable condenser manually shiftable to determine the frequency of oscillation of said oscillator throughout a relatively great range, and wherein said means for producing a tremulous effect includes a rotary condenser of relatively limited capacity connected in electrical circuit with said first named condenser to vary the eiiective capacity thereof within a relatively narrow range with respect to any selected setting.

I JOSEPH R. CUBERT.

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