Patent Publication Number: US-2005116684-A1

Title: Portable charger for mobile phones

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates generally to portable chargers for mobile phones, and more particularly to a portable charger for a mobile phone, which has a rechargeable battery therein, thus being easy to carry, in addition to charging the mobile phone.  
      2. Description of the Related Art  
      There have been known various kinds of chargers for mobile phones, for example, a stand-type charger and a jack-type charger. In this case, the stand-type charger is constructed such that a mobile phone is directly seated in the charger. Meanwhile, the jack-type charger is constructed to be connected a power terminal of the mobile phone, thus charging a rechargeable battery incorporated in the mobile phone.  
      The stand-type charger or the jack-type charger, which may be offered as options when purchasing a mobile phone, is used to charge the mobile phone. However, the stand-type charger or the jack-type charger has a problem in that it is difficult to carry, because the charger is usually placed on an item, such as a desk, or is installed at a supermarket or a charging station.  
      Of course, because the jack-type charger is small in volume, a user can carry the jack-type charger. However, the jack-type charger has a problem in that the charger must be connected to an outlet of a building, such as a house or an office, so as to supply electric power of 110 or 220 voltage to the jack-type charger.  
      Further, when a mobile phone is being charged using the conventional chargers, it is impossible to make a call with the mobile phone or listen to music using an audio function of the mobile phone.  
      Therefore, there is a growing demand on a charger for mobile phones, which is easy to carry, thus being available regardless of time and place, and which has a rechargeable battery in the charger, thus allowing a mobile phone to be charged without supplying electric power, and allowing a user to make a call and listen to music using the audio function of the mobile phone even when the mobile phone is being charged.  
      Further, the inventor of this invention proposed a portable charger for mobile phones, which may be offered in place of the stand-type charger or the jack-type charger that have been typically offered as the option when purchasing a mobile phone, or may be separately purchased, thus being convenient to use regardless of time and place.  
     SUMMARY OF THE INVENTION  
      Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a portable charger for mobile phones, which has a rechargeable battery in the charger, thus allowing a mobile phone to be charged without requiring a connection between the charger and an electric power source.  
      Another object of the present invention is to provide a portable charger for mobile phones, which has an earphone in the charger, thus allowing a user to make a call or listen to music even when the mobile phone is being charged.  
      A further object of the present invention is to provide a portable charger for mobile phones, which is constructed such that an earphone wire of the earphone returns to an original length thereof when the earphone wire is released or a button is pressed after the earphone wire is drawn out from a main body to a desired length, thus being convenient to store the earphone in the charger.  
      A still another object of the present invention is to provide a portable charger for mobile phones, which may be offered in place of a stand-type charger or a jack-type charger that are offered as an option when purchasing a mobile phone, or may be separately purchased, thus being convenient to use regardless of time and place.  
      In order to accomplish the above object, the present invention provides a portable charger for a mobile phone, including a main body having a cradle on a predetermined portion thereof so that the mobile phone is seated in the cradle, a rechargeable battery provided in the main body to be charged by electric power supplied to the portable charger, an accessory unit to support the main body in such a way that a user carries the portable charger, and an earphone unit provided to be drawn out from the main body.  
      The accessory unit includes at least one of a clamp provided at a predetermined portion of the main body to clamp the main body on a user&#39;s belt, a neck-strap coupled to the main body to allow the main body to be worn around a user&#39;s neck, and a mount unit detachably mounted to a predetermined position of a vehicle.  
      The earphone unit includes a rotating shaft which is provided in the main body, an earphone wire which is wound around the rotating shaft and is drawn out through a first hole formed on a sidewall of the main body so as to be extended to a desired length, and an elastic member which restores the extended earphone wire to an original state thereof by an elastic force of the elastic member.  
      The earphone unit further includes a stopper unit which is operated to stop the earphone wire when the earphone wire is drawn out from the main body to the desired length and then is released. The stopper unit is operated to make the earphone wire be wound around the rotating shaft by the elastic member.  
      The stopper unit includes a plate spring cap which houses and support the elastic member therein and rotates along with the rotating shaft of the earphone unit, with a plurality of notches being formed around an outer circumferential surface of the plate spring cap to be spaced apart from each other, a rotary pin, and a stop lever rotating about the rotary pin in a see-saw manner, with a first end of the stop lever engaging with one of the notches of the plate spring cap to prevent the plate spring cap from being undesirably rotated, and a second end of the stop lever being exposed to an outside of the main body through a second hole formed on the sidewall of the main body.  
      The second end of the stop lever is exposed to the outside of the main body through the second hole of the main body, thus forming a button which is operated to disengage the first end of the stop lever from the associated notch.  
      The portable charger further includes a support pin which elastically biases a side of the stop lever, thus preventing the first end of the stop lever from being undesirably removed from the associated notch.  
      The earphone unit includes an earphone wire which is drawn out from the main body to a predetermined length, and a wire winding unit which temporarily stops the earphone wire when the earphone wire is drawn out from the main body to a desired length. The wire winding unit allows the earphone wire to be retracted into the main body when the earphone wire is further drawn in a same direction and then is released.  
      The wire winding unit includes a shaft, a bobbin, a guide disc, a return spring, a ball, and a ball moving disc part. The shaft is provided in the main body. The earphone wire is wound around the bobbin, and the bobbin rotates about the shaft and is stopped by a predetermined frictional resistance. The guide disc moves along with the bobbin and selectively compresses the bobbin so that the predetermined frictional resistance occurs between the bobbin and the guide disc. The return spring returns the bobbin to an original position thereof. The ball moves along a guide path formed on the guide disc. The ball moving disc part is provided to face the guide disc so that the ball is placed between the guide disc and the ball moving disc part, and supports the ball and forms a path of the ball&#39;s movement based on a position of the earphone wire extended from the main body.  
      The ball moving disc part is integrally provided on an inner surface of the front cover to be depressed.  
      The ball moving disc part includes a plurality of ball seats in which the ball is seated according to the position of the earphone wire extended from the main body. At least one of the ball seats is provided to have a depth which is different from remaining ball seats.  
      The guide path of the guide disc includes a reciprocating section where the ball reciprocates, and an arc-shaped moving section extending from a first side to a second side of the reciprocating section, so that the ball moves along the arc-shaped moving section. An inclined step is formed at each of both ends of the arc-shaped moving section adjacent to the reciprocating section to guide the ball from the reciprocating section to the arc-shaped moving section according to the position of the earphone wire extended from the main body.  
      The portable charger further includes upper and lower caps mounted to the front and rear covers, respectively, thus preventing the rotation of the shaft of the wire winding unit. Each of the upper and lower caps includes a fitting projection fitted into a slit which is cut on each of upper and lower ends of the shaft of the wire winding unit to have a desired length, and a locking projection to lock each of the upper and lower caps to the corresponding front and rear covers.  
      The return spring comprises a spiral spring seated in a spring seat which is provided in the bobbin, with a first end of the return spring being supported by the slit which is provided on the upper end of the shaft of the wire winding unit, and a second end of the return spring being supported by the bobbin.  
      The cradle supports upper and lower ends of the mobile phone or both side surfaces of the mobile phone.  
      The cradle supports both side surfaces of the mobile phone, and the mobile phone is magnetically attached to and removed from a phone seating surface of the cradle.  
      The portable charger further includes a metal pad attached to a surface of the mobile phone, and at least one magnet provided on the phone seating surface so that the metal pad of the mobile phone is magnetically attached to the magnet.  
      The phone seating surface further includes a magnet support member which supports the magnet, a magnet cover which is placed on the magnet support member and has at least one magnet seating holes to seat the magnet therein, and a fastening member which fastens the magnet cover and the magnet support member to the phone seating surface.  
      The portable charger further includes an ornament pad which is made of a material to pass a magnetic force therethrough, and is attached to the magnet cover.  
      The portable charger further includes a circuit board which has a power terminal and is connected to the rechargeable battery to supply the electric power to the rechargeable battery, and a radio local transceiver mounted to a predetermined portion of the circuit board. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:  
       FIG. 1  is a perspective view of a portable charger for mobile phones, according to a first embodiment of the present invention;  
       FIG. 2  is a plan view to show an interior of a rear cover included in the charger of  FIG. 1 ;  
       FIG. 3  is a plan view to show an earphone unit and a stopper unit included in the charger of  FIG. 1 ;  
       FIG. 4  is a schematic sectional view of the earphone unit of  FIG. 3 ;  
       FIG. 5  is a perspective view of a portable charger for mobile phones, according to a second embodiment of the present invention;  
       FIG. 6  is a perspective view of a portable charger for mobile phones, according to a third embodiment of the present invention;  
       FIG. 7  is a perspective view of a portable charger for mobile phones, according to a fourth embodiment of the present invention;  
       FIG. 8  is an exploded perspective view to show a wire winding unit of the charger of  FIG. 7 ;  
       FIGS. 9   a  and  9   b  are respectively plan views to show a guide disc and a rear surface of a front cover of the charger of  FIG. 7 ; and  
       FIG. 10  is an exploded perspective view of a portable charger for mobile phones, according to a fifth embodiment of the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.  
      Reference now should be made to the drawings, in which the same reference numerals are used throughout the different drawings to designate the same or similar components.  
     First Embodiment  
       FIG. 1  is a perspective view of a portable charger for mobile phones, according to a first embodiment of the present invention,  FIG. 2  is a plan view to show an interior of a rear cover included in the charger of  FIG. 1 ,  FIG. 3  is a plan view to show an earphone unit and a stopper unit included in the charger of  FIG. 1 , and  FIG. 4  is a schematic sectional view of the earphone unit of  FIG. 3 .  
      As shown in  FIG. 1 , according to the first embodiment of the present invention, the portable charger  10  for mobile phones includes a main body  11  and an accessory unit. The main body  11  has a front cover  12  and a rear cover  14  that are separable from each other. The accessory unit supports the main body  11  in such a way that a user carries the charger  10 . Further, a cradle  16  is provided on the front cover  12  so that a mobile phone is seated in the cradle  16 .  
      First, second, and third holes  18 ,  20 , and  21  are formed on a sidewall of the rear cover  14 . A plug extending from the mobile phone is inserted into the first hole  18  to charge the mobile phone using a rechargeable battery  26  of the charger  10 . An earphone wire  33   a  of an earphone  33  is drawn through the second hole  20  to an outside of the main body  11 . Further, a button  40   b  which will be described later herein is provided in the third hole  21  to be exposed to the outside of the main body  11 .  
      As an example of the accessory unit, a clamp  24  is provided on a rear surface of the rear cover  14  to clamp the charger  10  on a user&#39;s belt, thus allowing the user to conveniently carry the charger  10 .  
      As shown in  FIG. 2 , the rechargeable battery  26 , an earphone unit  30 , and a stopper unit  35  are provided inside the rear cover  14 .  
      The rechargeable battery  26  functions to charge the mobile phone seated in the cradle  16 , and is connected to a circuit board  26   a  having a power terminal (not shown). When the charger  10  is not in use, it is necessary to connect an electric power source to the power terminal of the circuit board  26   a  through an electric wire so that the rechargeable battery  26  is charged by the circuit board  26   a . Of course, it is preferable that the rechargeable battery  26  have a quick charging structure.  
      As shown in  FIGS. 3 and 4 , the earphone unit  30  includes a shaft support disc  31 , a rotating shaft  32 , the earphone wire  33   a , and an elastic member. The shaft support disc  31  is mounted to a predetermined portion of the rear cover  14 . The rotating shaft  32  is coupled to the shaft support disc  31 . The earphone wire  33   a  is wound around the rotating shaft  32 , and is drawn out from the main body  11  through the second hole  20  to be extended to a desired length. The extended earphone wire  33   a  returns to an original state by an elastic force of the elastic member.  
      According to the first embodiment, a plate spring  34  is used as the elastic member. The plate spring  34  is housed and supported in a plate spring cap  38  which will be described herein later. The plate spring  34  retains an elastic force by the rotation of the rotating shaft  32 , and returns to the original state when an external force is eliminated.  
      The earphone unit  30  further includes the stopper unit  35 . The stopper unit  35  functions to stop the earphone wire  33   a  when the earphone wire  33   a  is drawn out from the main body  11  to a desired length and then is released. Further, the stopper unit  35  is operated to make the earphone wire  33   a  be wound around the rotating shaft  32  by the plate spring  34 .  
      The stopper unit  35  includes the plate spring cap  38 , a rotary pin  39 , and a stop lever  40 . The plate spring cap  38  rotates along with the rotating shaft  32 , with a plurality of notches  38   a ,  38   b , and  38   c  being formed around an outer circumferential surface of the plate spring cap  38  to be spaced apart from each other. The stop lever  40  rotates about the rotary pin  39  in a see-saw manner. A first end  40   a  of the stop lever  40  engages with one of the notches  38   a ,  38   b , and  38   c  of the plate spring cap  38  to prevent the plate spring cap  38  from being undesirably rotated, and a second end  40   b  of the stop lever  40  is exposed to an outside of the main body  11  through the third hole  21 .  
      In this case, each of the notches  38   a ,  38   b , and  38   c  has a triangular cross-section with a hooking surface, while the first end  40   a  of the stop lever  40  has a shape of a hook. Thus, as shown in  FIG. 3 , when the first end  40   a  of the stop lever  40  engages with one of the notches  38   a ,  38   b , and  38   c , the plate spring cap  38  can rotate clockwise but cannot rotate counterclockwise.  
      The second end  40   b  of the stop lever  40  forms the button which is exposed to the outside of the main body  11  through the third hole  21 . Thus, when the button  40   b  is pressed, the stop lever  40  rotates about the rotary pin  39 , and simultaneously the first end  40   a  of the stop lever  40  disengages from the associated notch  38   a ,  38   b ,  38   c.    
      The stopper unit  35  further includes a support pin  41 . The support pin  41  elastically biases a side of the stop lever  40  to prevent the first end  40   a  of the stop lever  40  from being undesirably removed from the associated notch  38   a ,  38   b ,  38   c . In other words, the support pin  41  biases the first end  40   a  of the stop lever  40  to the plate spring cap  38 .  
      The operation and operational effect of the portable charger  10  according to the first embodiment are as follows.  
      The mobile phone is seated in the cradle  16  of the charger  10  to be supported by the charger  10 . Next, the plug (not shown) extending from the mobile phone is inserted into the first hole  18 . Thus, while the mobile phone is being charged by the charger  10 , a user can make a call. Further, when the mobile phone is seated in the charger  10 , the user can carry the charger  10  on the user&#39;s belt using the clamp  24 .  
      When the user desires to make a call or listen to music during the charge of the mobile phone, the user draws the earphone wire  33   a  exposed to an outside of the rear cover  14  through the second hole  20 . At this time, the rotating shaft  32  installed in the rear cover  14  rotates, so that the length of the earphone wire  33   a  is further extended.  
      As the rotating shaft  32  rotates, the plate spring cap  38  and the plate spring  34  simultaneously rotate. Meanwhile, when the user stops drawing the earphone wire  33   a , the rotating shaft  32  and the plate spring cap  38  rotate in the reverse direction by the restoring force or elastic force of the plate spring  34 . During such rotations of the rotating shaft  32  and the plate spring cap  38 , the first end  40   a  of the stop lever  40  engages with one of the notches  38   a ,  38   b , and  38   c  of the plate spring cap  38 . Thereby, the rotation of the plate spring cap  38  is ceased. Thus, it is possible to use a common function of the mobile phone while maintaining the length of the earphone wire  33   a  as desired.  
      When there is no necessity of using the earphone wire  33   a  after making a call or listening to music, the button  40   b  of the stop lever  40  exposed to the outside of the rear cover  14  through the third hole  21  is pressed. Then, the stop lever  40  rotates about the rotary pin  39  in the see-saw manner, so that the first end  40   a  of the stop lever  40  disengages from the associated notch  38   a ,  38   b ,  38   c  of the plate spring cap  38 . Simultaneously, the rotating shaft  32  is rotated by the restoring force of the plate spring  34 , so that the earphone wire  33   a  is wound around the rotating shaft  32 , thus returning to the original state.  
      As such, according to the first embodiment, the portable charger is constructed to allow a user to carry, thus being available regardless of time and place. Further, the portable charger has the rechargeable battery  26  therein, thus being capable of charging the mobile phone without an additional supply of electric power. Furthermore, the portable charger allows the user to make a call or listen to music even when the mobile phone is being charged.  
     Second Embodiment  
       FIG. 5  is a perspective view of a portable charger for mobile phones, according to a second embodiment of the present invention. Referring to  FIG. 5 , the portable charger  110  has a neck-strap  124 , as an example of the accessory unit. The neck-strap  124  is coupled to the main body  11  to allow the main body  11  to be worn around a user&#39;s neck. Of course, it is preferable that coupling rings (not shown) be provided at predetermined portions of the main body  11  so as to easily couple the neck-strap  124  to the main body  11 .  
      According to the second embodiment, the user is capable of wearing the portable charger  110  around the user&#39;s neck using the neck-strap  124 . In this case, the operational effects of the portable charger  110  according to the second embodiment remain the same as the portable charger  10  according to the first embodiment.  
     Third Embodiment  
       FIG. 6  is a perspective view of a portable charger for mobile phones, according to a third embodiment of the present invention. Referring to  FIG. 6 , the portable charger  210  is removably mounted to a predetermined position of a vehicle. In order to removably mount the charger  210  to the vehicle, a mount unit (not shown) may be provided at a predetermined portion of the charger  210 .  
      However, in case where the portable charger  210  is not provided with the mount unit, as shown in  FIG. 6 , a connecting member  224  may be additionally provided to connect the charger  210  to a lighter jack  230  of the vehicle.  
      In this case, the connecting member  224  may have various shapes. However, in order to apply the connecting member  224  to a common jack-type charger, the connecting member  224  must have a simple structure, as shown in  FIG. 6 . That is, the connecting member  224  is constructed so that a first portion  224   a  thereof is inserted into the lighter jack  230  of the vehicle, while a second portion  224   b  thereof is inserted into a charging part  210   a  provided on a lower end of the charger  210 .  
      Or, the connecting member  224  may be constructed such that the first portion  224   a  thereof is inserted into the lighter jack  230  of the vehicle, and the second portion  224   b  thereof has a shape of a conventional socket so that a plug of an extension cable which is connected to the charging part  210   a  provided on the lower end of the charger  210  can be inserted into the socket of the connecting member  224 .  
     Fourth Embodiment  
       FIG. 7  is a perspective view of a portable charger for mobile phones, according to a fourth embodiment of the present invention,  FIG. 8  is an exploded perspective view to show a wire winding unit of the charger of  FIG. 7 , and  FIGS. 9   a  and  9   b  are respectively plan views to show a guide disc and a rear surface of a front cover of the charger of  FIG. 7 .  
      According to the fourth embodiment, the portable charger  310  includes a main body  311  and an accessory unit. The main body  311  has a front cover  312  and a rear cover  314  that are separable from each other. The accessory unit supports the main boy  311  to allow a user to carry the main body  311 .  
      A cradle  316  is provided on the front cover  312  so that a mobile phone is seated in the cradle  316 . A projecting terminal (not shown) is provided at a predetermined position of the cradle  316  to be inserted into a depressed terminal formed on a lower end of the mobile phone, and an elastic bar  316   a  is provided at a position of the cradle  316  opposite to the projecting terminal so as to prevent the mobile phone to be removed from the cradle  316 .  
      As an example of the accessory unit, a clamp  324  which has a construction different from the clamp  24  of  FIG. 1  is provided on a rear surface of the rear cover  314  to clamp the charger  310  on a desired item, such as the user&#39;s belt, thus allowing the user to carry the charger  310 . The clamp  324  of the fourth embodiment is constructed as follows. That is, when a first portion  324   a  of the clamp  324  is pressed, a second portion  324   b  of the clamp  324  is elastically spaced apart from the rear cover  314 . Conversely, when the first portion  324   a  is released, the second portion  324   b  comes into contact with the rear cover  314  again. Thus, such a clamp  324  allows the charger  310  to be easily held on a desired item, such as a belt.  
      A rechargeable battery  326  is provided inside the rear cover  314 . As described above, the rechargeable battery  326  functions to charge the mobile phone, and is connected to a circuit board  326   a  having a power terminal (not shown).  
      When the charger  310  is not in use, an electric power source is connected to the power terminal of the circuit board  326   a  through a charging electric wire or an adapter (not shown) so that the rechargeable battery  326  is charged by the circuit board  326   a.    
      In this case, a lead acid battery, a nickel cadmium battery, a nickel hydrogen battery, a lithium ion battery, a lithium polymer battery, and others may be used as the rechargeable battery  326 . Of course, it is preferable that the rechargeable battery  326  have a quick charging structure, thus being more convenient to use the rechargeable battery  326 .  
      According to the fourth embodiment, an earphone unit  330  includes an earphone wire  330   a  and a wire winding unit  340 . The earphone wire  330   a  has at an end thereof an earpiece, and is drawn out from the main body  311  to a desired length. The earphone wire  330   a  is wound around a bobbin  344  which will be described hereinafter. In this case, the bobbin  344  is constructed to have an additional boss, so that the earphone wire  330   a  is wound around the additional boss as well as the web of the bobbin  344 , and thus a desired length of the earphone wire  330   a  is secured.  
      When the earphone wire  330   a  is drawn out from the main body  311  to a desired length, the wire winding unit  340  functions to temporarily stop the extended earphone wire  330   a  at a predetermined position. Further, when the earphone wire  330   a  is released after being slightly drawn in the same direction, the earphone wire  330   a  returns to an interior of the main body  311  by the wire winding unit  340 .  
      Such a wire winding unit  340  includes a shaft  342 , the bobbin  344 , a guide disc  345 , a return spring  347 , a ball  348 , and a ball moving disc part  349 . The shaft  342  is provided in the main body  311 . The bobbin  344  around which the earphone wire  330   a  is wound rotates about the shaft  342 , and is stopped by a predetermined frictional resistance. The guide disc  345  moves along with the bobbin  344  to selectively compress the bobbin  344  so that the predetermined frictional resistance occurs between the guide disc  345  and the bobbin  344 . The return spring  347  functions to return the bobbin  344  to an original position thereof. The ball  348  moves along a guide path  346  formed in the guide disc  345 . The ball moving disc part  349  is provided at a position to face the guide disc  345  so that the ball  348  is placed between the ball moving disc part  349  and the guide disc  345 . The ball moving disc part  349  supports the ball  348 , and forms a path of the ball&#39;s movement based on a position of the earphone wire  330   a  extended from the main body  311 .  
      The ball moving disc part  349  compressing an upper portion of the ball  348  may be separately manufactured, and then assembled with other elements into a single structure. However, according to the fourth embodiment, the ball moving disc part  349  is integrally provided on an inner surface of the front cover  312  to be depressed.  
      As shown in  FIGS. 9   a  and  9   b , a plurality of ball seats  349   a  are provided in the ball moving disc part  349  so that the ball  348  is placed in the associated ball seat  349   a  according to the position of the earphone wire  330   a  extended from the main body  311 . At least one of the ball seats  349   a  is provided to have a depth which is different from remaining ball seats  349   a . When the ball  348  is placed in the ball seat  349   a  which has a shallow depth, the ball moving disc part  349  compresses the ball  348 . Thereby, there occurs the frictional resistance between the guide disc  345  and the bobbin  344 , so that the bobbin  344  is stopped and thereby the earphone wire  330   a  is stopped.  
      The ball  348  moves along the guide path  346  of the guide disc  345  as well as the ball seats  349   a  of the ball moving disc part  349 . In this case, the guide path  346  includes a reciprocating section  346   a  where the ball  348  reciprocates, and an arc-shaped moving section  346   b . The arc-shaped moving section  346   b  extends from a first side to a second side of the reciprocating section  346   a , so that the ball  348  moves along the arc-shaped moving section  346   b.    
      Further, an inclined step  346   c  is provided at each of both ends of the arc-shaped moving section  346   b  adjacent to the reciprocating section  346   a  to guide the ball  348  from the reciprocating section  346   a  to the arc-shaped moving section  346   b  according to the position of the earphone wire  330   a  extended from the main body  311 .  
      Referring to  FIGS. 9   a  and  9   b , at first, the ball  348  is placed in a portion A of the ball seats  349   a  of the ball moving disc part  349 . When the earphone wire  330   a  is drawn in such a state, the ball  348  moves to portions B, C, and D of the ball seats  349   a . In this case, when the user stops drawing the earphone wire  330   a , the ball  348  is placed in the portion B of the ball seats  349   a . In this case, the portions A and B of the ball seats  349   a  are shallower than the remaining ball seats  349   a , thus functioning to compressing the ball  348  toward the bobbin  344 .  
      While the ball  348  moves along the ball seats  349   a  of the ball moving disc part  349 , the ball  348  is placed in the reciprocating section  346   a  of the guide path  346 , and then moves to the arc-shaped moving section  346   b  after passing through one of the inclined steps  346   c.    
      Further, upper and lower caps  351  and  352  are provided on opposite ends of the wire winding unit  340  to close the opposite ends of the wire winding unit  340  and prevent movement of the shaft  342 . The upper cap  351  includes a fitting projection (not shown) fitted into a slit  342   a  which is cut on an upper end of the shaft  342 , and two locking projections (not shown) inserted into two locking holes  312   a  of the front cover  312 , respectively. Similarly to the upper cap  351 , the lower cap  352  includes a fitting projection  352   a  fitted into a slit  342   b  which is cut on a lower end of the shaft  342 , and two locking projections  352   b  inserted into two locking holes  314   a  of the rear cover  314 , respectively.  
      Thus, when the shaft  342  is placed at a predetermined position in the main body  311  and then the upper and lower caps  351  and  352  are respectively fastened to the upper and lower ends of the shaft  342  through the front and rear covers  312  and  314 , the fitting projection (not shown) of the upper cap  351  and the fitting projection  352   a  of the lower cap  352  are respectively fitted into the slits  342   a  and  342   b  which are cut on the upper and lower ends of the shaft  342 , thus preventing the shaft  342  from rotating.  
      A spring seat  344   a  is provided in the bobbin  344  which rotates when the earphone wire  330   a  is drawn or released, so that the return spring  347  is seated in the spring seat  344   a . According to the fourth embodiment, the return spring  347  comprises a spiral spring. A first end  347   a  of the return spring  347  is supported by the slit  342   a  which is provided on the upper end of the shaft  342  passing through the bobbin  344 , while a second end  347   b  of the return spring  347  is supported by the bobbin  344 .  
      Thus, when the earphone wire  330   a  is drawn out from the main body  311 , the return spring  347  is compressed. Thereafter, when the earphone wire  330   a  is released, the return spring  347  returns to an original state thereof, thus allowing the bobbin  344  to return to an original position thereof.  
      By such a construction, when the earphone wire  330   a  is drawn out from the main body  311 , the ball  348  moves from the reciprocating section  346   a  of the guide path  346  of the guide disc  345  through one of the inclined steps  346   c  to the arc-shaped moving section  346   b.    
      Simultaneously, the ball  348 , which is placed in the portion A of the ball seats  349   a  at first, moves to the portions B, C, and D of the ball seats  349   a  by the rotating bobbin  344  and guide disc  345  until the user stops drawing the earphone wire  330   a . At this time, the ball  348  is placed in the portion B which has a shallower depth.  
      Thus, the ball  348  placed in the portion B compresses the guide disc  345  and the bobbin  344 , so that the frictional resistance occurs between the bobbin  344  and an inner surface of the rear cover  314 . Due to the frictional resistance, the bobbin  344  is forcibly stopped. Since the rotation of the bobbin  344  is stopped, the earphone wire  330   a  is temporarily stopped at a desired length.  
      Meanwhile, when the earphone wire  330   a  is slightly drawn in the same direction and then is released, the ball  348  moves from the portion B to the portions C and D which are more deeply formed. At this time, the compressed return spring  347  returns to the original state thereof, so that the earphone wire  330   a  returns to the original position thereof in the main body  311 .  
     Fifth Embodiment  
       FIG. 10  is an exploded perspective view of a portable charger for mobile phones, according to a fifth embodiment of the present invention. The portable charger  410  of the fifth embodiment has a construction similar to the portable charger  310  of the fourth embodiment shown in  FIG. 7 .  
      As shown in  FIG. 10 , the portable charger  410  includes a main body  411  and an accessory unit. The main body  411  has a front cover  412  and a rear cover  414  that are separable from each other. An earphone  430  having an earphone wire  430   a  is retractably coupled to the main body  411 . Further, as an example of the accessory unit, a clamp  424  is provided on the rear cover  414 .  
      Meanwhile, the cradle  316  (see,  FIG. 7 ) is constructed to support the upper and lower ends of a mobile phone C/P. However, in this case, different kinds of chargers must be required to charge different kinds of mobile phones.  
      In order to solve the problem, as shown in  FIG. 10 , the portable charger  410  is constructed such that the mobile phone C/P is seated in a phone seating surface  416  by a magnetic force while both side surfaces of the mobile phone C/P are supported by phone support walls  416   a  and  416   b . Of course, in this case, the mobile phone C/P must be connected to the charger  410  via a connection line, so that charging power is supplied from the charger  410  to the mobile phone C/P. Because such a construction is known to those skilled in the art, the construction will not be described in detail herein.  
      A simple method of holding the mobile phone C/P using a magnetic force is as follows. That is, a metal pad  438  is attached to a rear surface of the mobile phone C/P, and a plurality of magnets  432  are provided on the phone seating surface  416  to be in magnetic contact with the metal pad  438  of the mobile phone C/P.  
      As shown in  FIG. 10 , the portable charger  410  may further include a magnet support member  430 , a magnet cover  434 , and a plurality of fastening members  436 . The magnet support member  430  supports the magnets  432 . The magnet cover  434  is placed on the magnet support member  430 , and a plurality of magnet seating holes  434   a  are provided on the magnet cover  434  so that the magnets  432  are seated in the corresponding magnet seating holes  434   a . The magnet cover  434  and the magnet support member  430  are integrally fastened to the phone seating surface  416  by the fastening members  436 .  
      Further, an ornament pad  437  which is made of a material to pass a magnetic force therethrough may be attached to the magnet cover  434  so that the charger  410  has a good appearance and advertising effects. Of course, a name of a charger manufacturing company may be provided on the ornament pad  437 .  
      When the above-mentioned elements are sequentially mounted to the phone seating surface  416  as shown in  FIG. 10 , thus producing the portable charger  410 , the portable charger  410  is capable of compatibly charging various kinds of mobile phones.  
      The present invention is described herein with reference to the above embodiments, but this invention is not limited to the embodiment.  
      In the above-mentioned embodiments, the plate spring is used as an elastic member. But, a coil spring, an elastic cord, and others may be used as the elastic member without being limited to the plate spring. Further, the construction of the earphone unit may be changed according to the kind of the elastic member.  
      Further, according to the embodiments, the earphone unit, the stopper unit, and the first, second, and third holes are provided at the rear cover. But, the above-mentioned elements may be provided at the front cover or provided at predetermined positions of an interior of the main body.  
      Further, according to the embodiments, a user uses the function of the mobile phone using the earphone wire. However, it is possible to use the function of the mobile phone by a wireless earphone communicating with a radio local transceiver, for example, a radio module having bluetooth chips. It is preferable that the radio module be mounted to a circuit board. But, the radio module may be installed at a position other than the circuit board.  
      According to the above embodiment, a metal pad is attached to a rear surface of a mobile phone. However, it is unnecessary to attach the metal pad to the mobile phone, if the mobile phone is made of a metal which is attracted by a magnet.  
      As described above, the present invention provides a portable charger for mobile phones, which has a rechargeable battery in the charger, thus allowing a mobile phone to be charged without the necessity of connecting the charger to an electric power source.  
      Further, a portable charger for mobile phones has an earphone therein, thus allowing a user to make a call or listen to music even when the mobile phone is being charged.  
      According to the present invention, a portable charger for mobile phones is constructed such that an earphone wire of the earphone returns to an original length thereof when the earphone wire is released or a button is pressed after the earphone wire is drawn out from a main body to a desired length, thus being convenient to store the earphone in the charger.  
      Further, a portable charger for mobile phones may be offered in place of a stand-type charger or a jack-type charger that are offered as an option when purchasing a mobile phone, or may be separately purchased, thus being convenient to use regardless of time and place.  
      Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.  
      The entire disclosure of Korean Patent Application No. 2003-37078 filed Nov. 27, 2003 and Korean Patent Application No. 2004-3577 filed Feb. 12, 2004 are hereby incorporated by reference.