Abstract:
A portable radio communication device comprising a housing and a buzzer that rings on activation to alert a user of an event, the buzzer being disposed adjacent the inner surface of the housing and next to an audio outlet orifice for the buzzer provided in the body cover member, wherein the housing has a channelled recess provided in its outer surface in the area of the audio outlet orifice.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to portable radio communication devices, and more particularly to mounting arrangements for ringer buzzers for such devices. 
     Ringer buzzers, sometimes simply called buzzers, are the audio transducers in a mobile communication device such as a portable radiotelephone which ring on activation to alert the user of an incoming call or other event. Typically, in the mobile phone a buzzer is mounted directly onto one of the printed circuit boards (PCB&#39;s) and once the PCB is assembled in relation to the phone housing the buzzer is located next to an orifice in the housing through which the ringer sound is emitted when the buzzer is activated. The PCB&#39;s are mounted in the phone by fixing them into the rear cover member of the housing, for example by screwing them down in the vertical direction. The body or orifice support for the buzzer is provided in the rear face of the cover member and therefore sealing the buzzer against the rear cover in the vertical direction is straight forward because it is brought into alignment with the seal and the orifice in the vertical direction. This is because the sound outlet is at the rear of the phone. 
     The drawback of such an arrangement between the buzzer and cover member is that because the sound outlet is on the back face of the phone, if the phone is placed on a table or pushed against the users body, for example in a pocket, then the sound outlet port becomes blocked (either by the surface of the table or the body) and this can seriously effect the buzzer audio output from the phone. This obviously in turn makes it harder for the user to hear the buzzer when it is ringing, which could lead to missed calls. 
     One solution that has been used to overcome this problem is to provide the buzzer orifice at the side of the phone. In this way, when a phone is laid flat on a table surface, the buzzer is directed sideways from the phone and is therefore not obstructed. This type of buzzer again is initially mounted on a PCB and the PCB is assembled by lowering it in a vertical direction into the cover member of the phone, with the buzzer being received in a sealing boot of the phone. This arrangement is shown in FIG. 1 of the accompanying drawings. As is apparent, the buzzer needs to be sealed in a horizontal direction against the side of the phone, while only compressing the parts concerned in a vertical direction. The result is either poor sealing or a clash of the parts as they are slid past one another making assembly difficult. 
     SUMMARY OF THE INVENTION 
     Against this background, the present invention seeks to overcome the difficulties with the prior art buzzers outlined above. Accordingly, the present invention provides a portable radio communication device comprising a housing and a buzzer that rings on activation to alert a user of an event, the buzzer being disposed adjacent the inner surface of the housing and next to an audio outlet orifice for the buzzer provided in the body cover member, wherein the housing has a channelled recess provided in its outer surface in the area of the audio outlet orifice. 
     By means of the invention, even if the communication apparatus is laid flat on for example a table their will be a duct for allowing the sound produced by the buzzer to be outletted to the surrounding environment. In effect, the duct is defined by the channel recess and the surface of the table. As a result, such communication apparatus would benefit in that the sound of the buzzer would not be obstructed or muffled in such circumstances. 
     Furthermore, because the audio outlet orifice is provided in the rear surface of the cover member, sealing of the buzzer can be effected in a vertical direction, i.e. in a plane parallel to PCB mounting. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will now be described by way of example with reference to the accompanying drawings in which 
     FIG. 1 illustrates a prior art arrangement for mounting a buzzer in a radio telephone; 
     FIG. 2 is a perspective view of a housing cover member incorporating a channelled recess in accordance with the present invention; 
     FIG. 3 is a side-on sectional view of the buzzer mounting arrangement of the present invention. 
     FIG. 4 illustrates alternative constructions of portable radio communication devices including a recess of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring initially to FIG. 2 there is shown a back cover member  10  of a radiotelephone. 
     The back cover member  10  is conveniently moulded from plastics material. It is designed with a great number of formations to house for example a PCB and receive the battery. Towards the upper end of the rear surface of the back cover member  10  near the corner formed where the top side  12  meets the rear surface  14  and spaced downwards from the topside, there is provided an outlet orifice port  16  for a buzzer ringer. As is apparent from FIG. 2, in the area of the back cover member  10  surrounding the audio outlet orifice  16 , the rear surface  14  thereof has a scooped out recess  18 . 
     The sectional view of FIG. 3 illustrates the profile of the scooped out recess  18  in greater detail. The audio outlet orifice  16  is located substantially centrally in relation to the scooped out recess  18 . The wall of the back cover member  10  is indented and follows a smooth inwardly curved “S” profile. The recess  18  has a generally concave configuration that extends lengthwise to define a channelled recess which extends from below the orifice  16  to the edge  12  of the top side surface of the radiotelephone. Accordingly, when the radiotelephone is placed flat on a surface such as a desk or table or in a briefcase the scooped out recess  18  together with the flat surface forms an audio passageway which acts to guide the sound from the orifice  16  out into the surrounding environment. 
     Referring still to FIG. 3, the sectional view shows a formation that straddles the audio outlet orifice  16  which extends inwardly from the internal surface of the cover member  10 , formations which from FIG. 3 appear to be a pair of legs  20 . These however in the preferred embodiment constitute a continuous annular wall  20 . The annular wall  20  is so constructed that the rim  22  presents is a flat ring with a plane substantially parallel to the plane of the radiotelephone. Because the location of the annular wall  20  is in the area of the recessed surface contour, the depth of the annular wall that forms it is graded, being deeper on one side than the other, so as to provide the flat rim surface  22 . 
     During the assembly process the PCB  24  from which the buzzer  26  depends, is lowered in a vertical axis into the back cover member  10 , in such a manner that the buzzer  26  is aligned with the annular wall  20 . Once the buzzer  26  is located against the rim  22  of annular wall  20 , the PCB  24  is fixed in relation to the back cover member  10  by any convenient means such as screws. In this way, the buzzer  26  is fixed in relation to the annular wall  20 . Sandwiched between the abutting surface of the buzzer  26  and the rim  22  of the annular wall  20  there is provided an annular sealing ring  28 , which acoustically seals the buzzer in an outward direction thereby preventing buzzer sound leaking back into the inside of the radiotelephone. Sealing is thereby effected in the direction in which the PCB board and buzzer are assembled into the radiotelephone. 
     In operation, when the buzzer  26  is activated the buzzer sound will be emitted and emerge from the outlet orifice  16 , be transmitted into the scooped recess  18  and outwards away from the radiotelephone. The recessed nature of the back cover member ensures that the outlet orifice is not closed when the radiotelephone is on or pressed against a flat surface. 
     The present invention may be embodied in other specific forms without departing from its essential attributes. For example the recess may conveniently take the form of a groove or channel. Also, instead of the buzzer being located next to an audio outlet port in the back cover member, it may well be that it is located in relation to the front cover member of the radio telephone if the audio outlet port is provided in the front cover member, in which case the scooped out recess is provided in the outer surface wall of the front cover member. Alternative constructions of portable radio communication devices utilising with advantage the present invention are depicted in FIG.  4 . Accordingly reference should be made to the appended claims and other general statement herein rather than to the foregoing specific description as indicating the scope of invention. 
     Furthermore, each feature disclosed in this specification (which term includes the claims) and/or shown in the drawings may be incorporated in the invention independently of other disclosed and/or illustrated features. In this regard, the invention includes any novel features or combination of features disclosed herein either explicitly or any generalisation thereof irrespective of whether or not it relates to the claimed invention or mitigates any or all of the problems addressed. 
     The appended abstract as filed herewith is included in the specification by reference.