US 2619960 A
Description (OCR text may contain errors)
| T. REYNOLDS 42,619,960
AURAL PROTECTIVE DEVICE Dec. 2, 1952 Filed Dec. 4, 1950 JNVENTOR.
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Patented Dec. 2, 1952 UNITED STATES PATENT OFFICE AURAL PROTECTIVE DEVICE Lee T. Reynolds, Hollywood, Calif. Application December 4, 1950, Serial No. 199,365`
This invention relates to an ear plug of the type designed for the protection and prevention of injuries to the tympanic membrane or ear drum of the ear, and has for its principal object the provision of a plug of this character which will not interfere with the transmission of sound vibrations to the ear drum at normal uniform levels, but which will act instantly to prevent sudden sounds of increased intensity from instantly reaching the ear drum so as to relieve all sudden impacts on the latter.
A further object of this invention is to provide what might be termed an ear check valve which will act instantly and efficiently to prevent sudden increases or decreases in air pressure from reaching the ear drum.
The invention is particularly useful for protecting the ear drum from the results of heavy gun nre, and is so designed that when the compression Waves from the discharge of a large gun reach the ear, the sound passage to the ear drum will be instantly closed, and when the vacuum or 10W pressure wave which follows a compression wave reaches the ear, the passage will be again closed to prevent sudden diiferentials in air pressure from occurring on the opposite faces of the ear drum which might result in injury or damage thereto.
The improved ear plug will also be found useful in shops, manufacturing plants, mining operations, etc., for protecting the ears from sudden extreme and unexpected sounds and noises. and yet allowing conversation and all other sounds of a uniform, continuous character to reach the ear drum without interference.
Other objects and advantages reside in the detail construction of the invention, which is designed for simplicity, economy, and efficiency. These will become more apparent from the following description.
In the following detailed description of the invention, reference is had to the accompanying drawing which forms a part hereof. Like numerals refer to like parts in all views of the drawing and throughout the description.
In the drawing:
Fig. 1 is a side view of the improved ear plug;
Fig. 2 is a longitudinal section therethrough, taken on the line 2-2 of Fig. 3;
Fig. 3 is an inner end view ear plug;
Fig. 4 is an outer end view thereof; and
Fig. 5 is a cross-section, taken on the line 5-5, Fig. 2.
In Fig. 1 the improved plug is illustrated subof the improved mediate the extremities of,
(Cl. 12S-152) stantially full-size, and in the remaining figures the scale has been increased to substantially four times the natural size. i
The improved ear plug employs a cylindrical housing or barrel l0 closed at its outer extremity by means of an outer cap member Il and at its inner extremity by means of an inner cap member l2. The cap members Il and l2 are shouldered to receive the extremities of the cylindrical barrel l0, and the shouldered portion of the outer cap H is forced into the outer extremity of the barrel with suilicient pressure to frlctlonally retain itself in place therein. The edge: of the inner extremity of the barrel l0 is rolled inwardly into a dovetailed groove l5 in the shoulder of the inner cap member l2, after the internal mechanism is in place, to retain the three members'l, il, and l2 permanently together.
The projecting portion of the inner cap member is conical and is axially tapped to form threads I4 for receiving the threaded extremity of an ear tube I3. The outer cap member Il is provided with a conical, axially positioned spring cavity It, the smaller diameter of which opens through the exterior of the cap member il. The inner cap member l2 is provided with a similar conical spring cavity I'i, which opens to the interior of the ear tube I3. The larger diameters of the conical spring cavities are cut back to form spring clamping channels I 8.
The inner faces of the cap members Il and l2 are spaced apart within the housing I0, and each of these faces carries an annular cup-shaped valve seat member i 9 having central sound ports 20. The seat members t over and are forced onto cir cular bosses formed on the inner faces of the cap members Il and l2 and have their flat faces facing each other in spaced-apart, parallel. relation within the housing I0.
A circular flutter between the flat faces of either seat member to close the central sound passage or port 20 therein. The flutter valve disc 2| is formed or mounted on a valve shaft 22 interand at right angles to, the axis of the latter. The shaft 22 extends axially outward from both faces of the valve disc 2l through both the ports 20 and into the conical spring cavities IB and l'l. Each extremity of the shaft 22 is provided with a spring-retaining ring or ange 23 set back from the adjacent extremity so that the extremities will project beyond the flanges 23 at each end of the shaft.
the smaller diameter of A watch-type hair spring 24 surrounds each extremity of the shaft 2|. Hair springs of this type consist of a lat steel wire wound in a dat spiral so that normally the entire spring lies in a common plane. In this device, however, the circumferential extremity of each spring 2A is clamped in one of the spring channels l between the adjacent seat the cap members 2|). The axial extremity of each spring is then slipped over one Vof the extremities of the shaft 2| so that it will lie against the flange 22 thereon. This distorts the two springs outwardly so that they form conical, spiral helixes, as shown in Fig. 2, which support the entire weight of the iiutter disc 2| and the shaft 2.2.
This manner of mounting the utter disc totally eliminates all friction and the disc hangs suspended in the opposing thrust of the two hair springs 2li.
A tubular rubber sleeve 25 is slipped over the eartube I3. The sleeve is provided with an inwardly extending annular ridge 25 which ts into a circumferential receiving groove formed in the ear tube i3. Two exible annular, dished anges 2 and 28 are formed on, and project about, the inner extremity of the sleeve 25 in spaced relation and serve to engage the walls of the oral cavity to retain the ear plug in place therein.
It will be noted that the ange 2i is of smaller diameter than the flange 28 so as to conform to the decrease in size of the natural ear cavity. The outer extremity of the rubber sleeve '.25 is flared outwardly to form a flexible cup 2d about the inner cap I2 to protect the valve mechanism from ear discharges and the like, and to form an outer seal in the ear canal about the ear tube I3.
It can be seen that normal air vibrations or waves caused from sounds or other means can pass through the cavity I6, the outer port 2G, past the disc 2|, and through the inner port 2&3 and the cavity I1 to the ear tube I3 to vibrate the ear drum.
During all normal vibrations or waves the valve disc will simply flutter or vibrate between the double seat members I8 without closing either port 2U. Should'a sudden, loud noise occur, or should there be a sudden increase in atmospheric air pressure, the velocity of the air through the outer port 2|] will act to force the valve disc instantly against the inner seat member I to seal the port 2li therein and so as to prevent a sudden or abrupt rise in air pressure on the ear drum.
Should a sudden or abrupt decrease in atmospheric pressure occur for any reason, such as in the wake of a pressure wave, the pressure on the inside of the flutter valve 2| will force it outwardly against the outer seat member |9 to close the port 20 therein to prevent a sudden evacuation on the outer face of the ear drum, which might result in damage thereto.
member I9 and one or" It can be seen from the above that the passage to the ear drum is normally open so that vibrations of all normal sounds can pass freely to the ear drum. The valve only functions on sudden and abrupt changes in sound volume or air pressure which act to create a pressure differential on opposite faces of the flutter valve disc 2|.
It is preferred to form the barrel It and the caps and I2 from non-magnetic material, such as aluminum, and to form ythe shaft y22 and the disc 2| from a resin plastic so as to avoid any interference due to adjacent magnetic fields.
While a specific form of the improvement has been described and illustrated herein, it is to be understood that the same may be varied, within the scope of the appended claims, without departing from the spirit of the invention.
Having thus described the invention, what is claimed and desired secured by Letters Patent is:
l. An aural protective device comprising a cylindrical barrel, inner and outer caps closing the opposite ends of said barrel and havingportions extending into the barrel, said caps being each formed with a ,central orice taperedtowards its outer end, a valve disc disposed loosely in the barrel between the inner ends of` said caps having a centrally located shaft projecting from the opposite sides of the disc and into the orifices through the inner ends thereof, spiral springs disposed vabout said shaft and located at opposite sides of said disc within the tapered orices, said springs being initially at and distorted longitudinally of the shaft to a conical formation and having their inner convolutions connected with the ends ofthe shaft and their outer convolutions engaging the inner faces of the caps about the inner ends .of said orifices, contraction of the springs being towards the disc in opposition to each other whereby the springs yieldably support the disc between and in spaced relation to the inner ends of the caps and permit movement of the disc towards either cap for closing the oriice thereof.
22 The structure of claim l, wherein an. annular valve seat member is mounted upony the inner end of each cap for `engagement by the disc when the latter is moved to a closed position, said seat members bearing against the outerfconvolutions of the springs andilrmly holding the springs to the caps.
LEE T. REYNOLDS.
REFERENCES CITED The iollowing'references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 2,465,606 Reynolds Mar. 29, 1949 2,487,038 Baum Novr 8, 1949