Handset for telephone apparatus.

The invention relates to a handset for telephone sets according to the preamble of claim 1.

Arrangements of this kind are known for example from DE 23 09 978 C3. In the structural design of the handsets to have a predetermined sensitivity for the hearing and speech capsules comply, but beyond that is crucial for the quality of the transmission behavior which circulated damping is to be realized. This circulation attenuation is a measure of how much of the light emitted by the earphone sound reaches the microphone capsule. With an insufficient circulation damping occur feedback that can lead to whistling. Such feedback is particularly to be feared when the handset is stored on a hard disk, as in the area of ​​this plate a significant sound reflection between handset and pad occurs. A feedback may also have the effect that the telephone communication is disturbed on neighboring lines of the handset associated telephone set. In digital telephone networks may be caused by the feedback an echo that the sound distorts and affects the intelligibility unfavorable.

Both in the device according to DE 23 09 987 C3 as well as in devices according to the DE 24-40899 A1 and DE-OS 20 61 692 sealing elements are provided which are used to a largely airtight connection of the hearing and speaking capsules with the housing will. This largely airtight storage of capsules in the area of ​​housing affects the recoverable circulation attenuation, because the total sound energy is feedback about the environment.

Object of the present invention is therefore to improve a handset of the generic type such that a sufficient circulation damping is ensured without impairing the external appearance of the handset.

This object is achieved with the features of claim 1.

By the sound-damping intermediate piece is formed an acoustic shunt that increases the circulating damper. The derived in the inner space of the telephone handset sound can no longer reach the sealed capsule opening. The special acoustic resistance of the opening ensures that the transmission quality characterizing frequency curve is not or at least only insignificantly affected.

The arrangement of the sound-deadening intermediate piece in the region of the earphone to avoid deterioration of the external appearance of the handset. The sound-damping intermediate piece is not visible from the outside and is thus not perceived by a viewer of the handset to be disturbing for molding.

According to a preferred embodiment, it is provided that the sound-deadening intermediate piece is designed as a foam insert. Alternatively, the sound-deadening intermediate piece may be formed by recesses in the region of the support, which have a roughness of approximately 1/100 mm.

In the drawing embodiments of the invention are shown schematically. Show it:<dl id="dl0001"><dt>Fig. 1:</dt><dd>a sectional view of a handset in the earpiece with a sound-deadening intermediate piece as a foam insert on the line II of Fig. 2,</dd><dt>Fig. 2:</dt><dd>a plan view of FIG. 1,</dd><dt>Fig. 3:</dt><dd>another sectional view of FIG. 1 with a sound-deadening intermediate piece by a roughened support.</dd></dl>

The handset of a telephone set shown consists essentially of a housing (1), which in its end regions cavities (5) having sound passage openings (9) for the air-borne sound. The cavities (5) take on capsules (3), which are designed as earphone and Microphone. The capsules (3) are received on the housing (1) via supports (4). Here, the capsule (3) approximately centrally by a retaining ring (7) having a plurality of lands (2) is mechanically held. In order to stiffen the housing (1) are arranged ribs (8). Further, a Verschraubungsbohrung (10) for the two housing parts (1) of the handset is shown.

Between earpiece (3) and support (4) is inserted, a sound-damping intermediate piece (6). This is carried out according to FIG. 1 as a foam insert. Alternatively, it is provided according to FIG. 3, to replace the foam insert by roughening the pad (6 ').

The use of foam inserts (6) is possible not only in the construction of new handsets. The foam inserts (6) may instead be provided as a retrofit kit for existing handsets.

The arrangement of the acoustically damped opening in the support (4), it is possible that circulating attenuation to increase by about 4 to 5 dB.