Abstract:
A microphone which does not need a hanger plate structure is provided. A conductive hanger knob is provided at the back of the rear case of a microphone case. The hanger knob has three layers of a conductive shaft part, an insulator part and a conductive bolt part in the named order from its center. The shaft part is electrically insulated from the bolt part. A notch that locks the bolt part of the hanger knob at a hanger surface is formed at a conductive hanger hook on which the microphone is hooked via the hanger knob. A support spring portion disposed at the back of the hanger surface urges the shaft part of the hanger knob locked at the notch in a direction of pushing the shaft part back toward the hanger surface. This provides electric conduction between the shaft part and the bolt part via the hanger hook.

Description:
RELATED APPLICATIONS 
       [0001]    This application is based on Japanese Patent Application No. 2008-268352 filed on Oct. 17, 2008 and Japanese Patent Application No. 2009-211633, and including specification, claims, drawings and summary. The disclosure of the above Japanese Patent Applications is incorporated herein by reference in its entirety. 
       FIELD OF THE INVENTION 
       [0002]    The present invention relates to a microphone provided at a communicating apparatus. 
       DESCRIPTION OF THE RELATED ART 
       [0003]    The ON/OFF mode of a communicating apparatus is changed over between a case where a microphone is hooked on a hanger hook and a case where the microphone is off-hooked therefrom. One hanger switch for detecting if a microphone is hooked on a hanger hook includes a microphone to which a printed circuit board for detection and a conductive hanger knob are mounted, and a metal hanger hook connected to the ground. Such a hanger switch detects the microphone being hooked on the hanger hook as the printed circuit board is electrically connected to the hanger hook via the hanger knob. 
         [0004]    According to the hanger switch for the microphone, wiring extending from the hanger hook to connect the hanger hook to the ground interferes with the operation of the hanger switch. In addition, the hanger hook involves a troublesome work of setting the wiring. In this respect, a hanger switch has been proposed which eliminates the need for the wiring to avoid the interference of such wiring and the troublesome work of setting the wiring at the time of mounting the hanger hook. 
         [0005]    For example, Unexamined Japanese Patent Application KOKAI Publication No. 2003-224897 describes a hanger switch for a microphone, which establishes electrical connection of the first contact of a printed circuit board to a hanger plate by means of a spring pin which presses the first contact and establishes electrical connection of the second contact of the printed circuit board to a hanger knob by means of a plate spring which presses the second contact. This configuration eliminates the soldering process at the time of assembling the microphone, and can completely isolate the rear case from the front case at the time of maintenance. 
         [0006]    Further, Unexamined Japanese Patent Application KOKAI Publication No. 2003-224897 also describes that the hanger plate includes hanger springs having elastic pressing portions with spherical surfaces protrusively formed at approximately cross-shaped arms, respectively, and a hanger plate body for protecting the microphone from shocks. According to the hanger plate, when the microphone is hooked on the hanger hook, at least two of the contact points provided at four locations on the hanger plate contact the hanger hook. This improves the mounting feeling and durability at the time of hooking the hanger knob on the hanger hook. 
         [0007]    Unexamined Japanese Patent Application KOKAI Publication No. 2001-160993 describes a hanger switch for a microphone, which is provided with a spring plate protrusively provided on the top surface of the hanger plate. This enhances the fixation at the time of hooking the microphone on the metal engagement portion provided at an automobile or the like, and suppressing the risk that sudden vibration would cause the microphone to be disengaged from the engagement portion. 
       SUMMARY OF THE INVENTION 
       [0008]    However, both of the hanger switches for a microphone proposed in Unexamined Japanese Patent Application KOKAI Publication No. 2003-224897 and Unexamined Japanese Patent Application KOKAI Publication No. 2001-160993 detect the hooking of the microphone as the hanger plate and hanger knob are made to be electrically conductive with each other via the hanger hook. Those hanger plates have complex shapes. Particularly, the hanger plate disclosed in Unexamined Japanese Patent Application KOKAI Publication No. 2003-224897 is configured to be a 2-part component, making the dies to be used in producing the hanger plate expensive. Further, the formation of a projection, such as an elastic pressing part or a spring plate, at the hanger plate brings about issues of having awkward feeling when the user holds the microphone with a hand, and restrictions on the design of the microphone. 
         [0009]    The present invention has been made in consideration of the above situations, and it is an object of the invention to provide a microphone which does not need a hanger plate structure. 
         [0010]    To achieve the object, a microphone according to the invention includes a microphone case, a hanger knob secured to the microphone case, and a conductive hanger hook on which the microphone case is hooked via the hanger knob, the hanger knob having a first conductor portion extending in an extension direction of the hanger knob, and a second conductor portion insulated from the first conductor portion, wherein the hanger hook having a hanger member that is formed with a notch to lock the hanger knob and is in contact with the second conductor portion in a locked state, and an urging member that is in contact with the first conductor portion and urges the hanger knob in a direction of pushing the hanger knob back toward the hanger member, with the hanger knob being locked with the notch. 
         [0011]    It is preferable that the urging member include a conductive plate spring. 
         [0012]    Further, a recess may be formed at that portion of the first conductor portion which contacts the urging member, and a projecting portion that fits in the recess may be formed at the plate spring. 
         [0013]    Furthermore, the second conductor portion may include a through hole formed in a direction of a center axis, a screw groove formed on one end portion of the second conductor portion which is secured to the microphone case, and a bolt that is screwed into a nut, provided inside the microphone case, to be secured to the microphone case, and the first conductor portion may extend inside the through hole through an insulator. 
         [0014]    Moreover, the microphone may further include a printed circuit board provided inside the microphone case, a first conductive member that provides electrical conduction between the first conductor portion and a first contact on the printed circuit board, and a second conductive member that provides electrical conduction between the second conductor portion and a second contact on the printed circuit board. 
         [0015]    It is preferable that the printed circuit board should have a detector that determines whether or not the microphone is hooked on the hanger hook, based on a voltage at the first contact and a voltage at the second contact. 
         [0016]    Further, the first conductive member may include a conductive rubber that is insulated from the second conductor portion, have conduction with the first conductor portion, and may be disposed at one end of the first conductor portion which faces the printed circuit board, the rubber being in contact with the first contact of the printed circuit board. 
         [0017]    Furthermore, the second conductive member may include a conductive plate spring that has one end secured to be conductive with the second conductor portion, and another end contacting the second contact of the printed circuit board. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]    These objects and other objects and advantages of the present invention will become more apparent upon reading of the following detailed description and the accompanying drawings in which: 
           [0019]      FIG. 1  is a perspective view showing a microphone according to an embodiment of the present invention; 
           [0020]      FIG. 2A  is an exploded perspective view showing the configuration of the microphone according to the embodiment; 
           [0021]      FIG. 2B  is a perspective view showing a hanger hook according to the embodiment; 
           [0022]      FIG. 3  is a front view showing the hanger hook according to the embodiment; 
           [0023]      FIG. 4  is a schematic cross-sectional view of the essential portions along cut line I-I in  FIG. 3  when the microphone according to the embodiment is hooked on the hanger hook; and 
           [0024]      FIG. 5  is a circuit diagram of a printed circuit board in the microphone according to the embodiment. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0025]    A microphone according to an embodiment of the present invention and a hanger hook for the microphone will be described below with reference to the accompanying drawings. 
         [0026]      FIG. 1  is a perspective view showing a microphone  1  according to the embodiment of the invention. As shown in  FIG. 1 , the microphone  1  is connected to the body of a communicating apparatus by a cord  3 . Transmission is enabled by pressing a press-to-talk switch  113  provided on the side surface of a microphone case  11  having a front case  112  and a rear case  111 . 
         [0027]      FIG. 2A  is an exploded perspective view showing the configuration of the microphone  1  according to the embodiment. 
         [0028]    As shown in  FIG. 2A , the microphone  1  with the front case  112  removed therefrom includes the rear case  111 , a weight  12 , a printed circuit board  13 , a hanger knob  14 , an O ring  15 , a plate spring  16 , a nut  17 , an insulating sheet  18 , and a conductive rubber  19 . 
         [0029]    The rear case  111  is made of a non-conductive material and has a hole  111   a  having two steps formed at the edge. The O ring  15  and a second flange portion  145  of the hanger knob  14  to be described later are locked at the steps formed at the edge of the hole  111   a  at the time the hanger knob  14  fitted in the O ring  15  is inserted in the hole  111   a  from the back face of the rear case  111 . 
         [0030]    The weight  12  is formed by a metal plate. The weight  12 , provided to give a weight to the microphone  1 , is attached to the front face of the rear case  111 . 
         [0031]    The printed circuit board  13  is mounted to the rear case  111  with the weight  12  in between. The printed circuit board  13  is connected with a connector  131  which is used to supply the voltage from outside and transmit a signal from the microphone  1 . A first contact  132  and second contact  133  which constitute a part of a circuit for a hanger switch are formed by a solder film or the like at the rear surface of the printed circuit board  13 . 
         [0032]    The hanger knob  14  has a shaft part  141 , an insulator part  142 , a bolt part  143 , a first flange portion  144 , and a second flange portion  145 . The shaft part  141  is formed of a conductor, and is positioned at the center axis of the hanger knob  14 . A projecting portion  141   a  protruding from the front face of the hanger knob  14  is formed at one end of the shaft part  141  which faces the printed circuit board  13 . This projecting portion  141   a  is fitted into a hole  19   a  formed in a conductive rubber  19  to be described later. A recess  141   b  in which a projection  24   a  of a support spring  24  of the hanger hook  2  to be described later is to be fitted is formed in the other end of the shaft part  141 . The insulator part  142  is formed of a non-conductor. As the insulator part  142  is formed so as to cover the shaft part  141 , the shaft part  141  and the bolt part  143  are electrically insulated from each other. The bolt part  143  is formed of a conductor so as to cover the insulator part  142 . A screw groove is formed on one end portion of the bolt part  143 , while a first flange portion  144  and a second flange portion  145  are formed at the other end portion thereof. That face of the first flange portion  144  which faces the rear case  111  will come into contact with a hanger surface  23  of the hanger hook  2  to be described later, when the microphone  1  is hooked on the hanger hook  2 . The second flange portion  145  is locked at the steps formed at the edge of the hole  111   a  when the hanger knob  14  is inserted in the hole  111   a  from the back face of the rear case  111 . Further, as the bolt part  143  having the screw groove formed thereon is screwed into the nut  17  inside the microphone  1 , the hanger knob  14  is secured to the rear case  111 . 
         [0033]    The O ring  15 , formed of a rubber material, prevents water or the like from entering the microphone  1  from a clearance between the hanger knob  14  and the hole  111   a . The O ring  15  is locked at the steps formed at the edge of the hole  111   a  of the rear case  111 , with the bolt part  143  of the hanger knob  14  being inserted in the O ring  15 . 
         [0034]    The plate spring  16 , made of a metal, has a hole  16   a  in which the bolt part  143  of the hanger knob  14  is to be inserted. The plate spring  16  is held and secured between the rear case  111  and the nut  17  with the bolt part  143  being inserted into the hole  16   a,  at the time of fastening the bolt part  143  and the nut  17  together. A contact-pressing arm portion  161  bent in the shape of an angled bracket (“&lt;”) is formed at the plate spring  16 . An end portion of the arm portion  161  presses the second contact  133  of the printed circuit board  13  mounted to the rear case  111 . This provides electric conduction between the second contact  133  and the bolt part  143  via the plate spring  16 . 
         [0035]    The nut  17  is made of a metal. As the nut  17  is fastened onto the bolt part  143  of the hanger knob  14  which is inserted into the hole  111   a  of the rear case  111 , from the front side of the rear case  111 , the hanger knob  14  is secured to the rear case  111 . 
         [0036]    The insulating sheet  18 , made of a non-conductive material, has a hole  18   a  in its center for insertion of the projecting portion  141   a  of the shaft part  141  of the hanger knob  14 . 
         [0037]    The conductive rubber  19 , formed of a conductive rubber material, has a hole  19   a  in its center in which the projecting portion  141   a  of the shaft part  141  of the hanger knob  14  is to be fitted. As the projecting portion  141   a  inserted through the insulating sheet  18  is fitted in the hole  19   a,  the conductive rubber  19  is attached to the shaft part  141  in such a state as to be electrically insulated from the bolt part  143 . That face of the conductive rubber  19  which faces the printed circuit board  13  presses the first contact  132  of the printed circuit board  13  which is mounted to the rear case  111 . Accordingly, the first contact  132  and the shaft part  141  have electric conduction therebetween via the conductive rubber  19 . 
         [0038]      FIG. 2B  is a perspective view showing the hanger hook  2 , which is made of a conductive material.  FIG. 3  is a front view of the hanger hook  2 . The hanger hook  2  has two fixed surfaces  21  for fixing the hanger hook  2 , a projecting surface  22  provided between the two fixed surfaces  21  and protruding in the cross-sectional shape of an approximately square bracket (“]”) with respect to the fixed surfaces  21 , and a support spring  24 . Each of the two fixed surfaces  21  has a hole  21   a  to be used to fix the hanger hook  2 . A U-shaped notch  23   a  is formed in the projecting surface  22 , extending from the fixed surface  21  to the hanger surface  23  protruding therefrom. The support spring  24  extends from the fixed surface  21  toward the hanger surface  23 . A projection  24   a  to be fitted in the recess  141   b  of the shaft part  141  is formed at the distal end of the support spring  24 . 
         [0039]      FIG. 4  is a schematic cross-sectional view of the essential portions along cut line I-I in  FIG. 3  when the microphone  1  is hooked on the hanger hook  2 . As shown in  FIG. 4 , the hanger knob  14  provided at the rear surface of the microphone  1  is inserted in the notch  23   a , and the first flange portion  144  is hooked at the lowermost end of the notch  23   a.  Then, the microphone  1  is hooked firmly with the repulsive force of the support spring  24  and the fitting of the projection  24   a  at the distal end of the support spring  24  in the recess  141   b  provided in the shaft part  141 . 
         [0040]    The operation of the hanger switch of the microphone  1  according to the embodiment will be described below. With the microphone  1  hooked on the hanger hook  2 , the support spring  24  contacts the shaft part  141 , causing the shaft part  141  of the hanger knob  14  to be conductive with the bolt part  143  via the hanger hook  2 . The printed circuit board  13  is electrically conductive with the shaft part  141  via the conductive rubber  19 . Further, the printed circuit board  13  is conductive with the bolt part  143  via the plate spring  16 . 
         [0041]      FIG. 5  shows an example of the circuit diagram of the printed circuit board  13  in the microphone  1  according to the embodiment. A resistor R 1  and a resistor R 2  are connected in series to each other, and are connected to a supply voltage Vcc and the ground, respectively. Likewise, a resistor R 3  and a resistor R 4  are connected in series to each other, and are connected to the supply voltage Vcc and the ground, respectively. The resistors R 1 , R 2 , R 3  and R 4  satisfy a relationship of R 1 ·R 4 ≠R 2 ·R 3 . The shaft part  141  is connected between the resistors R 1  and R 2 . The bolt part  143  is connected between the resistors R 3  and R 4 . The printed circuit board  13  has a detector  13   a  connected to the first contact  132  and the second contact  133 . The detector  13   a  is composed of, for example, a comparator circuit whose non-inverting input terminal is connected with the first contact  132  and whose inverting input terminal is connected with the second contact  133 . The comparator is adjusted to output a first voltage when the two input voltages are different and to output a second voltage when the two input voltages are almost equal. Likewise, the detector  13   a  may be composed of an inverter (NOT) circuit. When an input is supplied to one of the first contact  132  and the second contact  133  and the other one serves as a reference potential, the inverter circuit may be adjusted to output different logical values depending on the potential values of the first contact  132  and the second contact  133 . Specifically, the inverter circuit may be adjusted to output 1 (or 0) when the two potential values are different and to output 0 (or 1) when the two potential values are almost equal. 
         [0042]    Because the resistors R 1 , R 2 , R 3  and R 4  satisfy the relationship of R 1 ·R 4 ≠R 2 ·R 3 , with the microphone  1  off-hooked from the hanger hook  2 , the shaft part  141  and the bolt part  143  have different potentials with respect to the ground. The detector  13   a  detects that the voltages at the first contact  132  and the second contact  133  are different. Accordingly, it is possible to detect that the microphone  1  is off the hanger hook  2 . With the microphone  1  set on the hanger hook  2 , the first contact  132  and the second contact  133  are connected to each other. As a result, the detector  13   a  detects that the first contact  132  and the second contact  133  have the same voltage. Accordingly, it is possible to detect that the microphone  1  is hooked on the hanger hook  2 . The detector  13   a  sends a signal indicative of the detected state to the body of the communicating apparatus (not shown) from the connector  131  via the cord  3 . 
         [0043]    The circuit of the printed circuit board  13  is not limited to the example shown in  FIG. 5 . For example, either the resistor R 2  or resistor R 4  may have 0 Ω, i.e., either the shaft part  141  or the bolt part  143  may be grounded. The circuit of the printed circuit board  13  has only to set the voltages of the shaft part  141  and the bolt part  143  different from each other with the microphone  1  off-hooked from the hanger hook  2 , and set the voltages substantially the same with the microphone  1  hooked on the hanger hook  2 . The detector  13   a  may be any detector circuit as long as the circuit has an adequate input impedance as compared with the resistors R 1 , R 2 , R 3  and R 4 , and can discriminate the different voltage states and the identical voltage state of the first contact  132  and the second contact  133 . 
         [0044]    The hanger knob  14  is not limited to the shape shown in  FIGS. 2A and 4 . The bolt part  143  may not have a circular cylindrical shape. For example, referring to  FIGS. 2A and 4 , the bolt part  143  may have a structure to cover only the lower side of the shaft part  141  so long as the flange portion  144  which is engaged with the hanger hook  2  to be electrically conductive therewith is provided at the distal end of the bolt part  143 . Further, the shaft part  141  may not have a columnar shape. The shaft part  141  should be in contact with a part (support spring  24 ) of the hanger hook  2  to be electrically conductive therewith when the microphone  1  is hooked on the hanger hook  2  with the hanger knob  14 . 
         [0045]    According to the embodiment, the configuration of the microphone  1  can allow the printed circuit board  13  to detect hooking of the microphone  1  on the hanger hook  2 , thus making it possible to eliminate the wiring to the hanger hook  2 . 
         [0046]    According to the embodiment, hooking of the microphone  1  on the hanger hook  2  can be detected with the structure of the hanger knob  14  alone, eliminating the need for providing the microphone  1  with the hanger plate structure. It is therefore possible to eliminate the troublesome work of processing the hanger plate and attaching the hanger plate to the rear case, and suppress restrictions on the design of the microphone. 
         [0047]    According to the embodiment, the hanger switch is comprised only of the hanger hook  2  and the hanger knob  14 . The embodiment can be adapted to a conventional microphone without a hanger switch if the hanger knob is modified and the printed circuit board is provided with contacts. 
         [0048]    Because the hanger hook  2  need not be provided with a projecting structure for pressing the hanger plate according to the embodiment, the hanger hook is superior to the hanger hook having the projecting structure in appearance and safety. 
         [0049]    In addition, the foregoing hardware configuration is illustrative, and can be modified and changed optionally as needed. 
         [0050]    Various embodiments and changes may be made thereunto without departing from the broad spirit and scope of the invention. The above-described embodiments are intended to illustrate the present invention, not to limit the scope of the present invention. The scope of the present invention is shown by the attached claims rather than the embodiments. Various modifications made within the meaning of an equivalent of the claims of the invention and within the claims are to be regarded to be in the scope of the present invention.