Acoustics – Anatomic or prosthetic relation – Ear and mouth
Reexamination Certificate
2000-07-11
2001-09-11
Dang, Khanh (Department: 2837)
Acoustics
Anatomic or prosthetic relation
Ear and mouth
C128S864000
Reexamination Certificate
active
06286622
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a hearing protector intended for placing in an auditory canal of a user. The hearing protector includes a sealing body with a channel extending through it and a muffling device which is connected to the sealing body and connects to the channel. The sealing body is adapted to be placed in an auditory canal, so that the channel extends between the auditory canal and the atmosphere, in which the channel has a distal end part at the side of the auditory canal and a proximal end part at the side of the atmosphere. The muffling device connects to the proximal end part of the channel and comprises a rotatable control element, which control element is provided with at least one through aperture. The muffling device further comprising a housing element, which housing element is provided with at least one through aperture, the control element and the housing element being rotatable relative to each other between rotational positions with a corresponding muffling value, with the result that the apertures in the control element and the housing element overlap each other to a greater or lesser extent depending on a mutual angle of rotation.
BACKGROUND OF THE INVENTION
Such a hearing protector is known from DE-A-40 08 982, which discloses a substantially solid sealing body which is made to measure for a particular user (otoplastic). The sealing body contains an aeration channel which is widened at the proximal end part. A muffling device is fitted in the widened end part. The muffling device consists of a cylindrical element which is provided with a through aperture. The through aperture is made eccentrically in the element, the diameter of the aperture corresponding approximately to the diameter of the aeration channel. On the front side, the element is provided with a slot in which a screwdriver can engage. In this way, the element can be rotated relative to the sealing device, with the result that the aeration channel is cleared to a greater or lesser extent by the through aperture.
A disadvantage with this known hearing protector is that the muffling device is difficult to control. If a specific muffling value is desired, said value is difficult or impossible to set or distinguish. The design of the muffling element is intended in particular for otoplastics, and it is ill suited for use on a hearing protector with a sealing body of a more open design intended for universal use. In the open position of the muffling device, inadequate sound muffling can be achieved as a result of the relatively large diameter of the through aperture in the cylindrical element. In the fully closed position of the muffling device, undesired acoustic leakage still occurs. Moreover, the muffling device cannot be controlled without an aid.
EP-A-0 333 298 and DE-U-93 13 061 disclose hearing protectors with muffling devices, in which the muffling device comprises a housing which is fixed in the channel of the sealing body and comprises a central bore, consisting of a cylindrical threaded part and a part which tapers in the distal direction. A correspondingly threaded adjusting pin, which is formed such that it is complementary to the tapering part of the bore, fits into the bore, which pin can be moved in the axial direction by rotation in the bore, with the result that the passage to the open environment can be adjusted. This permits a stepless adjustment of the passage, and thus of the muffling action of the muffling device. Said stepless adjustment of the muffling action is used for having the muffling action set once by a manufacturer, by way of measurement, at a value specified by a user.
As in the case of DE-A-40 08 982, it is also a disadvantage in this type of hearing protector that the muffling device is difficult to control. Any change in the muffling value to a different muffling value will usually have to be carried out again by the manufacturer by means of rotating the adjusting pin and at the same time measuring the muffling value. The setting of the muffling value will generally not be changed by the user. However, if the user still changes the setting of the muffling device himself, it will have to be carried out by feel, and there is a risk here that a muffling effect which is correct by feel will turn out to be too low a muffling value in certain circumstances, so that the user, without noticing it, runs the risk of hearing loss in the long run.
SUMMARY OF THE INVENTION
The object of the present invention is to overcome the abovementioned disadvantages, and in particular to provide a hearing protector in which several desired muffling values of a muffling device can be adjusted quickly, reliably and in a reproducible manner by a user himself. Another object of the invention is to provide a muffling device which is suitable for combining with a sealing body designed for universal use.
These objects are achieved according to the invention including a hearing protector. The muffling device comprises a housing element which has at least one through aperture. The elements are rotatable relative to each other between two or more discrete rotation positions with corresponding muffling values. In the discrete rotation positions the apertures in the elements overlap to a greater or lesser extent, depending on the mutual angle of rotation. Various specific muffling values, determined in advance by a manufacturer, can advantageously be set by the user himself in a simple and reproducible manner. The dimensions of the muffling device do not change when the muffling device is adjusted to another muffling value set during use. This provides a very compact hearing protector with adjustable muffling value. The control element and the housing element are provided with complementary position-indicating means, for indicating the two or more discrete rotation positions. Herewith the complementary position-indicating means comprise parts which, through a rotation of the elements relative to each other, snap or click into each other. The muffling device in each case can be rotated until a click is heard and/or felt by the user, which indicates that the muffling device is situationed in a discrete rotational position. If desired, the rotation of the muffling device may also be carried out when the hearing protector is in the user's ear.
The hearing protector with the muffling device according to the invention is suitable in particular for use with a sealing body suitable for universal use. Such sealing bodies are known in many forms; see, for example, NL-A-94 01 212 and U.S. Pat. No. 4, 540 063. However, there is still room for improvement in the wearing comfort and the muffling characteristics of these known sealing bodies. The present invention now provides a hearing protector with a muffling device in which a sealing body is provided which, on the one hand, gives optimum wearing comfort and, on the other hand, in the specific combination with the muffling device according to the invention results in desired muffling characteristics. To this end, the sealing body comprises a central tube having a channel therein, at least one shell provided on the tube and designed to rest in a sealing manner against an auditory canal, and an end wall bounding the distal end part of the channel and having an end edge part of elastically deformable material which is bent inwards in the radial direction. In this case the end edge part is dimensioned in such a way that it deforms elastically in the axial direction under an axial pressure load, for example as a result of fitting the sealing body in an auditory canal. Thus a hearing protector is provided having a universal sealing body made of a flexible plastic which can shut off the auditory canal of different persons without in the process exerting unpleasant or painful pressure on the walls of the auditory canal. With the hearing protector designed in this way, the readily deformable front wall part of the sealing body will yield in the optimum manner, while effective insertion of the earplug body in the auditory canal is still e
Dang Khanh
Hoffmann & Baron , LLP
Simply Silence Simsin B.V.
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