Audiphone earpiece

Jan. 30, 1940.

2,188,591

T. J. CARLSON

AUDIPHONE EARPIECE

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Patented Jan. 30,1940

2,188,591

UNITED STATES PATENT OFFICE

2,188,591 AUDIPHONE EARPIECE Thomas J. Carlson, San Francisco, Calif. Application April 16, 1938, Serial No. 202,479 4 Claims. (Cl. 179—107)

This invention relates to earpieces for audiphones, and has for its objects improvements in the construction of these devices which facilitate manufacture, assemblage and accessibility, and 5 provide for individual fitting to the ears of different persons.

Other advantages of the improved construction are extreme ruggedness combined with low cost of production, yet withal an earpiece giving 10 a high quality of performance. Other advantages of the improved construction will appear in the following description and accompanying drawing.

In the drawing: Figure 1 is a general view of 15 the completely assembled earpiece shown full size and attached to its electric cord.

Figure 2 is a greatly enlarged vertical central section of the earpiece in position shown in Figure 1.

Figure 3 is a plan view of the electro-magnet core piece. -

Figure 4 is a perspective view of the core winding.

Figure 5 is an end view of the base receptacle 25 of Figure 2 as seen with the diaphragm cap, and retaining ring removed.

Figure 6 is a perspective view of a modified form of the cap of the device.

In further detail, my improved earpiece which 30 is preferably made of a light metal, such as aluminum, though it may be made of Bakelite or any suitable plastic material if desired, comprises a base receptacle or cup I, formed with an enlarged open end covered over the open end by 35 a flexible steel diaphragm 2, surmounted by a cap 3 held in place by a threaded marginal collar 4, while within the cup is a U-shaped iron magnet core formed with a flat base 5 riveted at 6 to the bottom of the cup and provided with two 40 spaced pole pieces Ί, Τ, projecting upwardly to a point adjacent the underside of the diaphragm, while wound about one of the pole pieces is a coil 8, the terminals of which are respectively secured to one wire 9 or 9' of the double electric cord 9, 45 which enters the cup through an opening 10 formed in the side of the cup, the wire leads from the usual microphone receiving set worn on the person, and is not shown on the drawing as the present invention relates only to the construction 50 of the earpiece.

At the top of the cap 3 is an ear tube or nipple 11 for inserting into the auditory canal of the ear in the known manner, and with the enlarged end of the device or collar 4 seated within the 55 concha to be supported also at its margin by the tragus of the ear. The cap is belled outwardly above the diaphragm to form the usual sound box space X.

The special features of my construction include a cap member 3 formed with a hollow dome 5 12 with the. nipple threaded at its inner end and screwed into a hole drilled through the dome and tapped to suit. This provision of a dome provides for drilling the hole at any of the angles A, B, C, D, etc. to suit the particular angle of 10 the auditory canal of the ear being fitted after carefully ascertaining the correct angle, for I have found that there is a great difference in this angle in different persons’ ears and unless the angle of each ear is individually fitted, consider- 1β able discomfort ensues which detracts from the efficiency of the device, whereas when the canal angle is correctly provided for the user is hardly conscious of the mechanical presence of the device. . ²θ

Instead of providing a dome to facilitate drilling at the ascertained angle, the cap may have an elevated hollow portion of the form shown in perspective in Figure 6, and wherein the cap is designated 3' and the hollow protuberance 12' 25 shown here as generally triangular in form with the hypothenuse represented by a relatively wide curved wall 12'' anywhere along the center line F—F of which the hole for the nipple may be drilled. ³⁰

The cap 3 is formed with a marginal step or ledge 13 to receive an inwardly turned flange 4' of collar 14 so that the outer surface of the assembled collar and cap will be smooth and free from ridges to irritate the wearer, and the body 35 of the cup is beveled off as at ί' to smaller diameter so as to fit within the concha and it is in this annular beveled area that the hole 10 is drilled.

The, magnet is of one piece struck up out of a piece of sheet iron to form a large, round, flat 40 base 5 which fits within the lower end of the cup to center it and is secured to the bottom by the rivets 6 as explained. This makes an easily centered unit of great rigidity.

The coil 8 is separately wound on a flat mandrel 45 to the form shown in Figure 4, preferably of enameled wire with the first layer around a wrapping of thin insulating paper or fiber 14, and the remaining layers of wire each separated by a sheet of Cellophane 15, left projecting be- 50 yond the wire about a sixteenth of an inch at both ends and with the inner and outer terminals of the wires 8' and 8'' brought to the upper end of the coil, and after which the coil is simply pushed down over one of the poles 7 as far as it 55

2,188,581 will go, thfe projecting Cellophane insuring insulation at the lower end. The double electric wire is passed through hole 10, the leads 9 and 9' with bared ends are separated, and bent in op5 position directions around pole 7’, and pushed down between the coil and the pole to position shown in Figure 5, but before this a small patch of surgeon’s rubber tape is struck to the inner surface of the cup at opposite points as at 16, 10 and the terminals of the coil are respectively soldered to the ends of the cord, and after pushing down in place the soldered connections will each lie against one of the tape patches 16, and are each covered with another tape patch 17 15 which is pushed tightly around the joint to gum itself securely to the patch below and surrounding metal to hold the joint firmly in place.

In Figure 5 the wire joint at the right side of the view (that of wires 9' and 8') is shown rest20 ing against the first tape patch 16, but not yet covered with the upper patch 17, whereas the other joint is shown completed and covered as described. The assemblage of coil and wire ends fits snugly and resiliently over and between the 15 pole pieces so that it cannot come out or shake loose in use or rough handling, yet is very easily pulled out if necessary to renew the coil or inspect the same.