Abstract:
A sound generating device is mounted in a recess formed in a case, and a battery is mounted on the case. A pair of terminals are provided on the underside of the case. A pair of leads connect a pair of electrodes of the battery with the terminals.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a buzzer for a portable communication device such as a portable telephone and a beeper. 
   The portable communication device is operated by the power of a storage battery as a main source of electricity having a large capacity under normal conditions. In such a device, it is necessary to provide a backup source for preventing a memory from erasing data such as telephone numbers stored therein, if the voltage of the main source, or the main source is cut off. In addition, it is necessary to provide an auxiliary source to operate a buzzer even if the main source is cut off. 
   As an auxiliary source, a disk type small battery is used. On the other hand, as a sound source for calling sound and a warning sound of the portable communication device, a very small buzzer is used. 
   In general, the auxiliary battery is mounted on a source portion of a substrate, and the buzzer is attached to a position necessary for the portable communication device, which positions have no relation with each other. 
   Referring to  FIG. 7  showing a prior art, a buzzer  21  is disposed on a substrate (not shown) regardless of a battery  22 . The battery  22  is set in an insulation case  23  mounted on the substrate. The battery is connected to a control circuit for a memory and the buzzer through contact plates  24  and  25  connected to a circuit on the substrate. The battery is a storage battery charged at the same time as the charging of the main battery, and provided as a backup battery or a source for the buzzer. 
   In the prior art, since the battery and the buzzer are independently disposed, it is necessary to form a space on the substrate for mounting the battery, resulting in increasing of the size of the substrate and hence the size of the portable communication device. 
   Furthermore, the buzzer  21  and the case  23  for the battery  22  are manufactured in separate manufacturing processes, which causes the manufacturing and assembling costs to increase. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a sound generator having a battery which may be decreased in size and manufactured at a low cost. 
   According to the present invention, there is provided a sound generator for a portable device comprising, a case, a sound generating device mounted in the case, a battery mounted on the case, terminals provided on the case, a pair of leads connecting a pair of electrodes of the battery with the terminals. 
   The case has a recess on an outside wall thereof, and the sound generating device is mounted in the case. 
   Each of the leads comprises a resilient contact plate contacted with the corresponding electrode. 
   The sound generating device may be a buzzer. 
   The battery has an upper electrode and lower electrode. 
   The terminals comprise a pair of terminals for applying a voltage of the battery to a control circuit, and a pair of terminals for applying a voltage from the control circuit to the buzzer for operating it. 
   The battery is held by the contact plate engaged with the upper electrodes. 
   The contact plate holding the battery is offset. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a plan view of a sound generator according to the present invention; 
       FIG. 2  is a sectional side view of the sound generator; 
       FIG. 3  shows the underside of the sound generator; 
       FIG. 4  is a perspective view; 
       FIG. 5  is an explode perspective view; 
       FIG. 6  is perspective view showing a modification of terminals; and 
       FIG. 7  is a perspective view of a conventional sound generator. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to  FIGS. 1 and 2 , a sound generator  1  according to the present invention comprises a case  2  made of plastic, a buzzer  3  mounted in the case  2 , and a disc type small battery  8  attached on the case  2 , so as to expose the battery. The buzzer  3  as a sound generating device comprises a coil  4 , a core  5  and an armature  7 . An electronic current is supplies to the coil from a control circuit (not shown) to generate a buzzing sound. 
   On the case  2 , a circular recess  9  is formed as shown in  FIG. 4 . The small battery  8  has a positive electrode on the upper side thereof and a negative electrode on the underside thereof. Resilient metallic contact plates  10  and  11  are negative electrode. The battery  8  is resiliently held by the elasticity of the contact plate  10 . In order to facilitate to detach the battery  8  from the case  2 , the contact plate  10  is offset as shown in  FIG. 4 . 
   As shown in  FIG. 3 , the contact plates  10  and  11  are extended to the underside of the case  2  and bent on the underside. On the underside of the case  2 , four connecting terminals  12 ,  13 ,  14 , and  15  are attached at four corners. Each of the terminals  12  through  15  comprises a flat metal plate. The contact plates  10  and  11  are connected to two terminals  12  and  13 . 
   More particularly, each of bent portions  10   a  and  11   a  of the contact plates  10  and  11  are engaged with a groove  19  formed in the underside of the case  2  as shown in  FIGS. 4 and 5 . Each of the terminals  12  and  13  is upwardly bent in an inverted L-shape to form a connecting end  12   a  as shown in  FIG. 5 . The bent portion  10   a  ( 11   a ) is connected with the connecting end  12   a  by welding. Thus, the contact plates  10  and  11  are electrically connected with the terminals  12  and  13 . The terminals  14  and  15  are connected to the coil  4 . Furthermore, the case  2  has a sound discharge hole  16 . 
   The sound generator  1  is mounted on a printed circuit (not shown). The terminals  12 ,  13 ,  14  and  15  are connected to corresponding terminals of the control circuit, thereby applying a voltage to the control circuit from the battery  8  through the contact plates  10  and  11  and terminals  12  and  13 . A control signal is applied to the buzzer  3  from the control circuit through the terminals  14  and  15 , so that a buzzing sound emanates from the sound discharge hole  16 . 
   Although the contact plates  10  and  11  and the terminals  12  and  13  are separately made, each couple the contact plate  10  and terminal  12 , and contact plate  11  and terminal  13  may be made by a single plate. 
     FIG. 6  is a perspective view showing a modification of the device. Lead wires  17  and  18  are vertically connected to the terminals  12  through  15 . The wires are inserted in corresponding holes formed in a circuit board and bent on the underside of the circuit board, thereby connecting each terminal with a corresponding terminal of the circuit. 
   In accordance with the present invention, the battery is attached to the case of the sound generation. Therefore, the battery and the sound generator can be assembled in a small size. Since it is not necessary to manufacture a housing for mounting the battery, the manufacturing cost is reduced.