A HOUSING FOR A TRANSMITTER/RECEIVER, A TRANSMITTER/RECEIVER AND A METHOD OF ITS ASSEMBLY

Abstract: A housing (2) for a transmitter/receiver adapted to house a microphone means (8) includes a main body (3) having a portion defining a rear sound inlet (7), and a front cover (4) having a portion defining a front sound inlet (6), said microphone means (8) being provided with a microphone housing (8a) having a front portion (8b) defining at least one front opening (8c) to be acoustically associated with said front sound inlet (6) and a rear portion defining rear openings (8e) to be acoustically associated with said rear sound inlet (7). According to the invention, spacing means (10, 11) are provided for sealingly keeping the microphone means (8) substantially equidistantly in a space (18a, 18b) between said front sound inlet (6) and said rear sound inlet (7).

Description: A housing for a transmitter/receiver, a transmitter/receiver and a method of its assembly BACKGROUND OF THE INVENTION The present invention relates to a housing for a transmitter/receiver adapted to house a microphone means, said housing including a main body having a portion defining a rear sound inlet, and a front cover having a portion defining a front sound inlet, said microphone means being provided with a microphone housing having a front portion defining at least one front opening to be acoustically associated with said front sound inlet and a rear portion defining rear openings to be acoustically associated with said rear sound inlet. The invention also relates to a transmitter/receiver, such as a mobile telephone, or a cordless telephone, a satellite telephone or a walkie-talkie, including such a housing and a disconnectible or integrated power source, such as a battery. It also relates to a transmitter/receiver, for a stationary telephone having such a housing. The invention also relates to a method of assembling a transmitter/receiver of the above described kind. Such a housing for a transmitter/receiver and such a transmitter/receiver is known from US-A-5 682 418. The known housing however suffers from a drawback the design thereof does not allow automatic assembly, i.e. it is not adapted for serial production, as e.g. the microphone cannot be mounted in the housing without difficulties. The therein described transmitter/receiver is rather a product which is intended for extremely short series made by hand. The object of the present invention is therefore to improve the known transmit- ter/receiver such that a series production is allowed. SUMMARY OF THE INVENTION This object has been achieved by a housing as initially defined, wherein spacing means are provided for sealingly keeping the microphone means substantially equi- distant in a space between said front sound inlet and said rear sound inlet. Preferably, said spacing means includes a first sealing member adapted to be arranged between said front sound inlet and said space. Hereby is achieved a spacing means, which at the same time seals off the microphone in relation to the rest of the housing. It has also been achieved by the method as defined initially, wherein said first sealing member is adapted to receive a microphone means and to keep it centrally and equidistantly in relation to said front sound inlet and a rear sound inlet. Suitably, said first sealing member is adapted to seal off a microphone means of a predetermined size and form. Hereby is achieved that different kinds of microphones are allowed to be used in the production. Advantageously, the front cover is provided with a guide means for guiding said first sealing member towards an inner surface of said front cover. Hereby is achieved a fast mounting of the front cover towards the main body, while the spacing means is guided towards the front cover. Preferably, said guide means is provided with at least a first guide member, against which the first sealing member is adapted to seal, said first guide member protruding from said inner surface of the front cover. Hereby is achieved that the mounting of the front cover allows the spacing means to be guided to a predetermined location of the interior of said front cover. In particular, said first sealing member is provided with a flange having an annular protrusion, said flange being adapted to face a peripheral portion of the front portion of said microphone means, said annular protrusion being adapted to seal a substantially annular space between the housing of the microphone means and the micro- phone receiving member. Preferably, a printed circuit board means is adapted to be arranged between the main body and the front cover. Advantageously, said printed circuit board means defines a substantially circular trough-hole having a lateral opening allowing the circular-cylindrical portion of said first sealing member to be moved in a radial direction via said lateral opening to said through-hole, the side of the flange of the first sealing member facing the circular-cylindrical portion and being provided with an annular reinforcement member adapted to bear against the side of the printed circuit board, which is intended to face the main body. Hereby, a quick mounting of the spacing means is achieved before mounting of the front cover on the main body. DRAWING SUMMARY In the following the invention will be described with reference to the accompanying drawings, in which Figure la and lb are a perspective views of a mobile telephone having a micro- phone end, Figure 2 is a cross-section of the microphone end of the mobile telephone shown in figure 1, Figures 3 a and 3b are exploded views of the mobile telephone at the microphone end including a printed circuit board, Figures 4a and 4b illustrate insertion of a spacing means in different views. DETAILED DESCRIPTION Figure la and lb shows a mobile telephone 1, including a housing 2 including a main body 3 including a detachable or non-detachable, preferably rechargeable, battery 3 a and a front cover 4. The front cover 4 has a sound outlet 5, behind which, a loudspeaker is arranged. The front cover also has a front sound inlet 6, whereas the main body has a rear sound inlet 7. The front cover 4 is furthermore provided with openings 7a, in which push-buttons 7b are arranged, for allowing e.g. dialling of a telephone number or selecting a user option. A display 7c is provided for dis- play of information and a system connector 7d for connection to external power supply and external microphone and loudspeaker, so called hands-free equipment. Figure 2 is a cross-section of a part of the mobile telephone, including the main body 3, front cover 4 having an inner surface 4a, the front sound inlet 6 and the rear sound inlet 7. Between the front and rear sound inlets, a circular cylindrical microphone 8 of the uni-directional kind is provided. The microphone 8 has a housing 8a including a front portion 8b defining at least one front sound opening 8 c, which is directed towards the front sound inlet 6 of the front cover 4, and a rear portion 8d defining at least one rear sound opening 8e, which is directed towards the rear sound inlet 7 of the main body 3. For achieving the best sound quality, a uni-directional or bi-directional microphone should be arranged centrally between the front sound inlet and the rear sound inlet. For this purpose, an circular cylindrical microphone member or seat 9 for a prede- termined size of microphone 8 is provided. The seat 9 is furthermore an integral part of the system connector 7d. A front spacing means 10 is arranged between the mi- crophone 8 and the front cover 4. Likewise, a rear spacing means 11 is provided between the seat 9 and the main body 3. The front spacing means 10 and the rear spacing means 11 also constitute sound sealing members, the purpose of which is to insulate against sound that has penetrated into the housing at other locations, e.g. at the push-buttons 7b. Accordingly, both the front and rear spacing means 10, 11 are at least partly constituted by a resilient, e.g. elastomeric, material. Between the rear spacing means 11 and the main body 3, a sound damping member 12 covering the rear sound inlet 7 is provided for allowing less sound to penetrate to the microphone via the rear sound inlet 7, than via the front sound inlet 6. The mobile telephone 1 is furthermore provided with a printed circuit board 13, hereinafter called PCB. The PCB 13 has a through-hole 14, through which a substantially circular cylindrical portion 10a of the front spacing means 10 extends, while an annular flange member 10b of a larger diameter than the through-hole 14 is intended to bear against the side of the PCB 13 which is intended to face the microphone 8. The flange 10b has an annular surface 10c, which is provided with an annular protrusion lOd, of a diameter slightly larger than the diameter of the microphone, however of a diameter slightly smaller than an annular edge 9a of the circu- lar cylindrical seat 9. In order to achieve an even better contact, flange 10b is furthermore provided with an annular reinforcement member lOe, made of metal or hard plastics, which is intended to bear against the side of the PCB 13 facing the microphone in an annual groove lOf. This also causes the annular surface 10c to be pressed against the microphone and optionally against an annular surface 9b of the seat 9, whereas the annular protrusion lOd will be pressed into an annular space lOg between the microphone 8 and the seat 9. However, as shown in figure 2, a passage 15 for a microphone contact member 16 may be provided for allowing connection thereof to the PCB 13. The front cover 4 is furthermore provided with an annular protrusion 17 of a diameter, which is slightly larger than the diameter of the circular cylindrical portion 10a of the front spacing means 10. When the front cover 4 is mounted on the main body 3, the portion 10a is pressed into the annular protrusion 17, as the por- tion 10a is constituted by an elastomeric material. A sound insulation between the front spacing means 10 and the a space 18a between the PCB 13 and the front cover 4 is established. The rear spacing means 11 has a flat rear surface 19 and an annular protrusion 20 intended to bear against a rear surface 21 of the seat 9. A sound insulation between the rear spacing means 10 and the a space 18b between the PCB 13 and the mam body 3 is thereby established. It should be noted that in figure 2, the portions 10a, lOd and 20 have been shown in an uncompressed state for a better understanding of the figures. When correctly mounted, the spacing means 10 and 11 ensure that the microphone 8 is mounted equidistantly, i.e. centrally between the openings 6, 7. They also insulate against sound that has penetrated through the housing 2 into the from the interior thereof so that the sound received by the microphone is substantially pure, i.e. substantially without sounds causing interfering noise. Also acoustic feedback from the loudspeaker is avoided. Furthermore, the spacing means 10 and 11 create an optimal sound path for a uni-directional microphone. Figures 3a and 3b illustrate assembly of the mobile telephone 1 as seen from two different view angles. The PCB 13 is fastened to the main body 3 by means of screws 21a, thereby creating the above mentioned pressure on the rear spacing means 11. In turn, the front cover 4 is provided with a plurality of barb like protrusions 22, while the main body 3 is provided with thereto corresponding members 23. the protrusions 22 and members 23 together forming a snap lock. While mounting the front cover 4 on the main body 3, pressure is put on the front spacing means 10, so that a press-fit is created in relation to the annular protrusion 17. For facilitating mounting, the annular protrusion 17 is provided with a plurality of guide members 17a for guiding the circular cylindrical portion 10a of the front spacing means 10 towards the annular protrusion 17. It should be noted that each of the guide members 17a and the annular protrusion constitutes guide means for guiding the circular cylindrical portion 10a towards the inner surface 4a of the front cover 4. In order to facilitate quick assembly of the mobile telephone 1, the through-hole 14 includes a lateral opening 24, which is large enough to allow the circular cylindrical portion 10a of the front spacing means 10 to pass laterally therethrough - indicated by arrows in Figures 4a and 4b - while sliding the flange 10b in the groove 1 Of between the PCB 13 and the seat 9. MOUNTING When mounting the mobile telephone, the sound damping member 12 is put in place in front of the opening 7, see figures 2 and 3a. Thereafter the rear flat surface of the rear spacing means 11 is placed on the sound damping member 12. The system connector 7d with integrated seat 9 is then put in place, the annular protrusion 20 bear- ing against the a rear surface 21 of the seat 9. The microphone 8 is placed in the seat 9, whereafter the PCB 13 is placed on top of the of the system connector 7d and fastened to the main body 3 by means of the screws 21a. Before tightening the screws 21a completely, the flange 10b of the front spacing means 10 is slid into the groove 1 Of via the lateral opening 24. The circular cylindrical portion 10a protrudes through the through-hole 14. Thereafter, the screws 21a are tightened, causing the annular protrusion to be deformed. The front cover 4 is placed on top of the main body 3, and is fastened thereonto by means of the snap lock. i.e. the protrusions 22 and members 23, while gently press- ing at the front sound inlet, the guide members 17a thereby guiding the circular cy- lindrical portion 10a of the front spacing means 10 towards the annular protrusion 17, which then is allowed to embrace the circular cylindrical portion 10a. Of course, it would be possible to perform the assembly in such a way that the spacing means 10, 11, the seat 9 etc. are fastened onto the front cover by screwing the PCB 13 thereonto, whereafter the main body is snapped onto the front cover.

Claims: CLAIMS 1. A housing (2) for a transmitter/receiver adapted to house a microphone means (8), said housing (2) including a main body (3) having a portion defining a rear sound inlet (7), and a front cover (4) having a portion defrning a front sound inlet (6), said microphone means (8) being provided with a microphone housing (8a) having a front portion (8b) defrning at least one front opening (8c) to be acoustically associated with said front sound inlet (6) and a rear portion defrning rear openings (8e) to be acoustically associated with said rear sound inlet (7), characterised in that spacing means (10, 11) are provided for sealingly keeping the microphone means (8) substantially equidistant in a space (18a, 18b) between said front sound inlet (6) and said rear sound inlet (7). 2. A housing according to claim 1, wherein said spacing means (10, 11) includes a first sealing member (10) adapted to be arranged between said front sound inlet (6) and said space (18a). 3. A housing according to claim 2, wherein said first sealing member (10) is adapted to seal off a microphone means (8) of a predetermined size and form. 4. A housing according to claims 2 or 3, wherein the front cover (4) is provided with a guide means (17, 17a) for guiding said first sealing member (10) towards an inner surface (4a) of said front cover. 5. A housing according to claim 4, wherein said guide means (17, 17a) is provided with at least one first guide member (17), against which the first sealing member (10) is adapted to seal, said first guide member (17) protruding from said inner surface (4a) of the front cover (4). 6. A housing according to claim 5, wherein said first sealing member (10) is provided with a flange (10b) having an annular protrusion (lOd), said flange being adapted to face a peripheral portion of the front portion (8b) of said microphone means (8), said annular protrusion (lOd) being adapted to seal a substantially annu- lar space (lOg) between the housing (8a) of the microphone means and a microphone receiving member (9). 7. A housing according to anyone of the preceding claims, wherein a printed circuit board means (13) is adapted to be arranged between the main body (3) and the front cover (4). 8. A housing according to claim 7, wherein said printed circuit board means (13) defines a substantially circular trough-hole (14) having a lateral opening (24) allowing a circular-cylindrical portion (10a) of said first sealing member (10) to be moved in a radial direction via said lateral opening (24) to said through-hole (14), the side of the flange (10b) of the first sealing member (10) facing the circular- cylindrical portion (10a) being provided with an annular reinforcement member (lOe) adapted to bear against the side of the printed circuit board, which is intended to face the main body (3). 9. A transmitter/receiver, such as a mobile telephone (1), or a cordless telephone, a satellite telephone or a walkie-talkie, including a housing (2) according to anyone of the preceding claims and a disconnectible or integrated power source (3 a), such as a battery. 10. A transmitter/receiver, for a stationary telephone including a housing (2) according to anyone of the claims 1-8. 11. A method of assembling a transmitter/receiver, including the following steps: a) mounting a printed circuit board means (13) on a main body (3) of a housing (2); b) moving a circular-cylindrical portion (10a) of a first sealing member (10) through a lateral opening (24) of a substantially circular trough-hole ( 14) of said printed cir- cuit board means (13), while a flange (10b) of the first sealing member (10) facing the circular-cylindrical portion (10a) is adapted to lie against the side of the printed circuit board (13), which is faces the main body (3); c) mounting a front cover (4) on said main body (3) for covering said printed circuit board (13), wherein said circular-cylindrical portion (10a) extends from the side of the printed circuit board (13) that faces the main body (3) to the front cover (4); wherein said first sealing member (10) is adapted to receive a microphone means (8) and to keep it centrally and equidistantly in relation to said front sound inlet (6) and a rear sound inlet (7). 12. A method according to claim 11, including providing said flange (10b) with an annular reinforcement member adapted to bear against the side of the printed circuit board (13) that faces the main body (3).

Inventors: ENGBLOM GOERAN, ENGBLOM, GOERAN
Applicants: ERICSSON TELEFON AB L M, TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
Application year: 2000
Main classification: H04M1
IPC codes: H04M1, H04R1, H05K7