Abstract:
A charging device for a battery pack in which universality is achieved without restrictions imposed by the charging terminal unit of the battery pack, a demand for size reduction can be met, and in which the request for safety and reliability may be met with reduction in production cost. To this end, the battery pack charging device includes an ejection member  14  thrust by a battery pack  60  loaded in a battery pack loading unit  6  to accumulate the elastic force, and a lock member  13  engaged with a mating lock portion  66  to hold the battery pack in the battery pack loading unit. On completion of the charging operation, the locked state by the lock member is annulled and the battery pack is uplifted by the ejection member from the battery pack loading unit.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    This invention relates to a battery pack charging device for charging a battery pack which is loaded on a potable electronic equipment for supplying the DC power thereto.  
           [0003]    2. Description of Related Art  
           [0004]    A battery pack charging device has a battery pack loading unit, formed as a recess on e.g., a major surface of a casing of the device, for charging the battery pack loaded therein. In general, the battery pack charging device includes a DC power supply circuit, and a current detection circuit, or a control circuit, enclosed in a housing, and also includes, in the battery loading section, a charging electrode terminal member for connection to a charging terminal member of the battery pack, and a communication terminal for exchanging the information with the battery pack. The battery loading section of the battery pack charging device is provided with a detection switch for detecting the loading of the battery pack. When the loading of the battery pack into the battery loading section has been confirmed by the detection switch, the DC current is supplied from the DC power supply to the charging electrode for charging the battery pack.  
           [0005]    In general, a lock mechanism for holding the loaded state of the battery pack and a popup mechanism for hoisting the battery pack from within the battery pack holding section are provided in the battery pack loading unit of the battery pack charging device. The lock mechanism includes a lock member including a lock part formed at the foremost part thereof and which is slidably mounted in the casing so as to be biased to be protruded into the battery pack loading unit. When the battery pack is loaded in the battery pack loading unit, the lock part of the lock member is engaged in a lock recess formed in the battery pack to keep the loaded state.  
           [0006]    The role of the popup mechanism is usually simultaneously performed by an electrode terminal member connected to the charging terminal member of the battery pack. For example, the free end of the electrode terminal member, formed by e.g., a plate spring, is projected into the battery pack loading unit. In the popup mechanism, when the battery pack is loaded in the battery pack loading unit, the electrode terminal member is connected to a charging terminal member of the battery pack and is thrust by the battery pack to accumulate the force of elasticity. When the charging operation comes to a close and the lock mechanism is actuated, the popup mechanism lifts the battery pack by the force of elasticity to facilitate removal of the battery pack from the battery pack loading unit.  
           [0007]    In the above-described battery pack charging device, since the electrode terminal member simultaneously performs the role of the popup mechanism, the shape-related degree of freedom of the charging electrode unit, inclusive of the electrode terminal member, is limited by the structure of the battery pack side charging terminal unit. The conventional battery pack charging device suffers from the drawback that it must be constructed with different structures of the battery pack loading unit, lock mechanism or the charging electrode unit, in keeping with design parameters for outer shapes of the battery pack or design parameters of the charging terminal unit, which design parameters may be variegated depending on the design parameters of the electronic equipment. As a consequence, the conventional battery pack charging device lacks in universality.  
           [0008]    Moreover, in the battery pack charging device, respective terminals of the charging terminal unit are reduced in pitch, in keeping with attempts in reducing the size and thickness of electronic equipment, consequent upon the improved performance of the secondary cell, so that the terminals of the charging terminal unit are also reduced in pitch. The conventional battery pack charging device has a drawback that, since each electrode terminal member is usually constructed by a plate spring, which plate spring must be afforded with the function of accumulating sufficient force of elasticity to hoist the battery pack, it is difficult to reduce the size of the battery pack charging device.  
           [0009]    Moreover, in the conventional battery pack charging device, each electrode terminal member, formed by a plate spring to perform the popup function, is mounted as it is protruded into the inside of the battery pack loading unit. If, in the battery pack charging device, the battery pack is placed within the battery pack loading unit but is not being charged, the electrode terminal member and the electrode terminal member facing each other need to be kept in the non-connected state in order to prevent e.g., overcharging to maintain safety. If, in the battery pack charging device, burrs are produced or acute protrusions are encountered on the outer periphery of each electrode terminal member, formed by a plate spring, there is raised such a problem that these burrs or protrusions interfere with the guide holes in the casing to produce malfunctions or electrical shorting, or with the operator&#39;s fingers during operation or handling.  
           [0010]    In order to overcome the above problems, encountered with the battery pack charging device, it may be contemplated to maintain non-conducting states for the respective electrode terminal members or to use a molded cover member for overlying the outer periphery of the battery pack charging device. This solution is difficult to resort to because the respective electrode terminal members are directly contacted with the respective charging terminal members. With the conventional battery pack charging device, it is necessary to take such measures as removing the burrs produced on the outer periphery, or to chamfer the protrusions, by way of post-processing. The necessity of taking these measures as well as the shape-related restrictions accounts for increased costs of the battery pack charging device.  
         SUMMARY OF THE INVENTION  
         [0011]    It is therefore an object of the present invention to provide a battery pack charging device in which the structure-related degree of freedom imposed by the charging terminal unit of the battery pack, as well as safety and reliability, may be improved, and in which the demand for reduction in size and cost of the device is met.  
           [0012]    The present invention provides a battery pack charging device in which a battery pack, including a charging terminal unit arranged on a first lateral surface and a mating lock portion on a second lateral surface opposite to the first lateral surface, is loaded in a battery pack loading unit formed as a recess in a major surface of a device casing, from the first lateral surface. The battery pack charging device includes a charging electrode unit arranged on a first lateral surface section of the battery pack loading unit, to which the first lateral surface of the battery pack is abutted, the charging electrode unit being connected to the charging terminal unit of the loaded battery pack, a holder provided to the first lateral surface section of the battery pack loading unit for holding the first lateral surface of the loaded battery pack, a lock member provided on a second lateral surface section opposite to the first lateral surface section of the battery pack loading unit and slidably mounted to the major surface of the device casing, the lock member including a lock portion engaged with the mating lock portion of the loaded battery pack, and an ejection member having one end rotatably carried by a support formed in an inner surface of the device casing and having its other end facing a guide opening formed in the bottom surface of the second lateral surface section of the battery pack loading unit, the ejection member being biased to be intruded into the guide opening.  
           [0013]    In the present battery pack charging device, the ejection member is thrust by the battery pack loaded into the battery pack loading unit, so that an elastic force is accumulated in the ejection member. The first lateral surface of the battery pack is held by the holder in this state, while the lock member locks the mating lock portion of the second lateral surface to accommodate the battery pack. When the charging operation comes to a close, the lock member is slid to unlock the mating lock portion from the lock portion, while the ejection member is uplifted from the bottom surface of the battery pack loading unit under the elastic force stored.  
           [0014]    In the present battery pack charging device, in which the battery pack loaded in the battery pack loading unit is reliably uplifted by the ejection member, the charging electrode unit can be constructed with a relatively free shape not restricted by the shape of the charging terminal member of the battery pack, thus assuring universality. In the present battery pack charging device, the charging electrode members of the charging electrode unit can be reduced in pitch and size, in keeping with the reduction in size and pitch of the charging terminal members of the battery pack, thus reducing the size of the device. Moreover, the charging electrode members and the charging terminal members can be reliably connected to one another without the risk of erroneous connection, thus improving reliability. Additionally, the post-processing, such as deburring, can be omitted, thus further reducing the production cost.  
           [0015]    In the present battery pack charging device, including the ejection member thrust by the battery pack loaded in the battery pack loading unit to accumulate the elastic force therein, and the lock member engaged with the mating lock portion to hold the battery pack in the battery pack loading unit, the locked state by the lock member is annulled, on completion of the charging operation, to uplift the battery pack from the battery pack loading unit, so that the charging electrode unit can be designed to free shape without being restricted by the shape of the charting terminal unit, thus achieving universality. With the present battery pack charging device, the pitch and size of the charging electrode unit and the charting terminal unit can be reduced, while the overall device may also be reduced in size. Moreover, the charging electrode unit and the charging terminal unit mating therewith can be reliably connected to one another, without the risk of erroneous connection, thus improving operational reliability. Additionally, post-processing such as deburring of the respective charging electrode members can be omitted to achieve further reduction in production cost. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a perspective view showing a battery pack charging device embodying the present invention and a battery pack to be loaded on and charged by the battery pack charging device.  
         [0017]    [0017]FIG. 2 is a longitudinal cross-sectional view of the battery pack charging device with the inner mechanism thereof being omitted.  
         [0018]    [0018]FIG. 3 is an exploded perspective view for illustrating component members of a battery pack lock mechanism and a popup mechanism provided in the battery pack loading unit of the battery pack charging device.  
         [0019]    [0019]FIG. 4 is a bottom plan view for illustrating the battery pack loading unit.  
         [0020]    [0020]FIG. 5 is a longitudinal cross-sectional view for illustrating the structure of the popup mechanism.  
         [0021]    [0021]FIG. 6 is a bottom plan view for illustrating essential parts of another embodiment of the battery pack loading unit.  
         [0022]    [0022]FIG. 7 is a perspective view for illustrating the structure of the charging electrode unit provided in the battery pack loading unit.  
         [0023]    [0023]FIG. 8 is a perspective view for illustrating essential parts of an electrode block member provided in the charging electrode unit.  
         [0024]    [0024]FIG. 9 is a longitudinal cross-sectional view of the electrode block member.  
         [0025]    [0025]FIG. 10 is a longitudinal cross-sectional view for illustrating the operation of a detection unit provided to the electrode block member for detecting the loading of the battery pack into the battery pack loading unit.  
         [0026]    [0026]FIG. 11 is a schematic view for illustrating the operation of loading the battery pack to the battery pack loading unit.  
         [0027]    [0027]FIG. 12 is a schematic view showing the state of loading the battery pack in the battery pack loading unit.  
         [0028]    [0028]FIG. 13 is a schematic view for illustrating the operation of unlocking the battery pack locked by a lock member.  
         [0029]    [0029]FIG. 14 is a schematic view for illustrating the battery pack popup operation.  
         [0030]    [0030]FIG. 15 is a perspective view looking from the bottom side of the battery pack.  
         [0031]    [0031]FIG. 16 is a perspective view looking from the upper surface side of the battery pack.  
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0032]    Referring to the drawings, a battery pack charging device  1 , according to a preferred embodiment of the present invention, is now explained in detail. The battery pack charging device  1  includes a casing combined from an upper casing  2  and a lower casing  3 , both formed of synthetic resin. Within this casing, there are enclosed e.g., a DC power supply circuit unit, a current detection circuit and a control circuit unit. The battery pack charging device  1  includes a power supply terminal unit  4 , having a pair of pin terminals  4   a,    4   b,  on the outer rim of the casing, with a power supply cable being connected to the power supply terminal unit. The current is supplied over a power supply cable from an external power supply, not shown, to the DC power supply circuit unit of the battery pack charging device  1 . The battery pack charging device  1  is provided with a power supplying unit  5  on a bottom surface  6   d  of a battery pack loading unit  6 , as later explained, and is connected to a relay cord, not shown, for directly relaying and furnishing the current from the external power supply to the equipment to which the battery pack is connected.  
         [0033]    To the battery pack charging device  1 , a battery pack  60  of a width slightly broader than the battery pack loading unit  6  is loaded in a substantially horizontal state with its foremost part  60   a  directed slightly downwards. The battery pack charging device  1  is provided with an electrode unit  7  for supplying the charging current to the battery pack loading unit  6  and a loading detection unit  8  for detecting the loading of the battery pack  60 . The battery pack  60  is charged in a preset fashion after detecting by e.g., a current detection circuit whether or not the battery pack  60  may be charged. The battery pack charging device  1  is provided with a positioning rib  9  for setting the position of the battery pack  60  loaded in the battery pack loading unit  6  and a stopper projection  10  for prohibiting its extrication. The battery pack charging device  1  is also provided with a lock/eject mechanism  11  for locking the loaded battery pack  60  and for lifting the battery pack  60  from within the battery pack loading unit  6 .  
         [0034]    The battery pack  60  is used e.g., as a power supply for a video camera, and includes a rectangular casing of a broader width, combined from an upper half  61  and a lower half  62 , bot of which are molded from synthetic resin, such as polycarbonate resin. The battery pack  60  includes, in its casing, a chargeable lithium ion secondary cell, in a manner not shown in detail. The battery pack  60  includes its one longitudinal side as a loading surface  60   a  into the battery pack charging device  1 , and has a charging terminal unit  63  on one width-wise side of this loading surface  60   a.  The charging terminal unit  63  will be explained in detail subsequently.  
         [0035]    The battery pack  60  includes a positioning recess  64  which is formed astride the loading surface  60   a  and the opposite side lateral surface facing the charging terminal unit  63 . When the battery pack  60  is loaded in the battery pack loading unit  6  of the battery pack charging device  1 , the positioning recess  64  is engaged by the positioning rib  9 , so that the battery pack is loaded in position. On an upper surface  60   c  in proximity to the loading surface  60   a  of the battery pack is formed an index  65  for demonstrating its loading direction to the battery pack charging device  1 . The longitudinal lateral surface of the battery pack  60  opposite to the loading surface  60   a  of the battery pack  60  is formed as a lock surface  60   b  which is locked by the lock/eject mechanism  11  when the battery pack  6   s  is loaded in the battery pack charging device  1 . A lock recess  66  is formed in the lock surface  60   b.    
         [0036]    Referring to FIG. 15, the charging terminal unit  63  is provided in a fitting recess  67  formed in the loading surface  60   a  for opening to a bottom surface  60   d  and a lateral surface of the battery pack  60 , as shown in FIG. 15. The battery pack  60  has its loading surface  60   a  locked by the fitting recess  67  engaging with the stopper projection  10  when the battery pack  60  is loaded in the battery pack loading unit  6  as will be explained subsequently. The charging terminal unit  63  includes a cathode charging terminal member, a communication terminal member and an anode charging terminal member, each formed of a metal plate. These terminal members are arrayed in this order in the fitting recess  67  from the inner side towards the outer side. Although not shown in detail, the respective terminal members are arrayed in slits  69   a  to  69   d  so as not to be exposed to outside. In the charging terminal unit  63 , a convexed protection rib  68  is formed for surrounding a slit site accommodating the respective terminal members.  
         [0037]    In the battery pack  60 , the respective terminal members of the charging terminal unit  63  are connected to the respective electrode members of the electrode unit  7 , by the battery pack charging device  1  being housed in the battery pack loading unit  6 , as will be explained subsequently in detail. The battery pack  60  sends the information on design parameters or the charging information through the communication terminal member to the battery pack charging device  1 . The charging current is supplied through the cathode charging terminal member and the anode charging terminal member to perform the preset charging on the enclosed secondary cell.  
         [0038]    The above-described battery pack  60  is loaded into the battery pack loading unit  6 , from the loading surface  60   a  first. The battery pack  60  is positioned in the battery pack loading unit  6  and kept in its loading state. The battery pack loading unit  6  is a rectangular recess substantially corresponding in profile to the outer shape of the battery pack  60  and has a longitudinal lateral side as an abutment surface  6   a  against which abuts the loading surface  60   a  of the battery pack  60  being loaded. Referring to FIGS. 1 and 2, the battery pack loading unit  6  has its lateral sidewall sections  6   b,    6   c  formed to an arcuate shape with the height of the lateral sidewall sections decreasing progressively from its loading surface  60   a  towards a longitudinal mid portion. By this outer shape of the lateral sidewall sections  6   b,    6   c,  the battery pack loading unit  6  permits the battery pack  60  to be readily be gripped from its both sides.  
         [0039]    The bottom surface of the battery pack loading unit  6  represents a supporting surface  6   d  carrying the bottom surface  60   d  of the battery pack  60  being loaded. The battery pack  60  has a depth corresponding to approximately one half the depth of the battery pack  60 , and houses the battery pack  60  therein with the bottom surface  60   d  of the battery pack  60  resting on the bottom surface  6   d  of the battery pack  60 , with the upper surface of the battery pack  60  being exposed to outside. On the inner surface of the loading surface  60   a  of the battery pack  60  is arranged the electrode unit  7 , towards one longitudinal lateral side of the battery pack, as shown in FIG. 1. The loading detection unit  8  is arranged next to the electrode unit  7 , while the positioning rib  9  is formed on the same inner surface towards the opposite side longitudinal lateral side of the battery pack loading unit  6 . In the bottom surface  6   d  of the battery pack loading unit  6 , there is provided a power supplying unit  5  in the form of a substantially L-shaped opening, in the vicinity of the positioning rib  9 .  
         [0040]    The stopper projection  10  is formed as one with the abutment surface  6   a  of the battery pack loading unit  6  in association with the electrode unit  7 . The lock/eject mechanism  11  is provided to an upper surface  2   a  of the upper half  2  lying opposite to the abutment surface  6   a  of the battery pack loading unit  6 . A display unit  12  is provided on the upper surface  2   a  of the upper half  2  lying towards its side provided with the power supply terminal unit  4  to display the power supplying state to the equipment connected in circuit and the charging state of the battery pack  60 .  
         [0041]    The lock/eject mechanism  11  is provided with a lock member  13  for locking the lock surface  60   b  of the battery pack  60  loaded on the battery pack loading unit  6  and an ejection member  14  for uplifting the battery pack  60  from the battery pack loading unit  6 . The lock/eject mechanism  11  includes a spring member  15  combined with the bottom surface side of the ejection member  14  for applying the elastic force thereto and a torsion spring  16  for biasing the lock member  13  towards the battery pack loading unit  6 .  
         [0042]    The upper half  2  is formed with a recess  17  in its upper surface  2   a  opening to the battery pack loading unit  6  and with a cut-out guide opening  18  in the bottom surface  17   a  of the recess  17 , as shown in FIGS. 2 and 3. The recess  17  is formed with a width-wise cut-out guide opening  17   b  in its bottom surface  17   a  for opening to the supporting surface  6   d  of the battery pack loading unit  6 , as shown in FIG. 3. The lock member  13  is assembled to this upper half  2  through the cut-out guide opening  17   b  for slidably combining the lock member  13  to the recess  17  and to the cut-out guide opening  18 . The upper half  2  is formed with a rectangular guide opening  19  in the supporting surface  6   d  of the battery pack loading unit  6  in association with the recess  17 . The ejection member  14  is carried by extending an actuation portion  26  outwards from this guide opening  19 . A mounting boss  20  for securing one end of a spring member  15  by a set screw  20  to the inner surface of the upper half  2  is mounted upright on the upper half  2 , as shown in FIG. 4.  
         [0043]    The inner surface of the upper half  2  is formed as one with rib wall section carrying the inner surface of the spring member  15 , from a mounting boss section  20 . A first positioning projection  21   a  and a second positioning projection  21   b  are formed upright on a portion of the rib wall section. Each of plural positioning projections  21  is used for positioning the spring member  15 , secured to the mounting boss section  20 , as will be described in detail subsequently. The inner surface of the upper half  2  is formed as one with a pair of bearing boss sections  22   a,    22   b  on both sides of the cut-out guide opening  18 . The bearing boss sections  22   a,    22   b  are formed as one with the inner surface of the upper half  2  in a spaced apart relation to each other, and is formed with a bearing opening of a substantially U-shaped cross-section, with the open side of the letter U being directed to the mounting boss section  20 , as shown in FIG. 5. The bearing boss sections  22   a,    22   b  are adapted for rotatably carrying supporting shafts  28   a,    28   b  formed as one with the ejection member  14  in a manner which will be explained subsequently in detail.  
         [0044]    The lock member  13  is formed of synthetic resin as one with an actuation portion  23 , a slide portion  24  and a spring retainer  25 . The actuation portion  23  has an outer shape substantially corresponding to the opening shape of the recess  17  and a thickness substantially corresponding to the depth of the recess  17 . An arcuate-shaped finger support projection  23   a  is formed at one end of the actuation portion  23 . The actuation portion  23  is formed as one with a lock projection  23   b  on its lateral surface opposite to the finger support projection  23   a.  The lock projection  23   b  is a rectangular projection formed in register with a lock recess  66  formed in the lock surface  60   b  of the battery pack  60 , and is adapted for being protruded in the inside of the battery pack loading unit  6  when the lock member  13  is mounted to the recess  17 .  
         [0045]    The slide portion  24  is formed as one with the lateral surface of the actuation portion  23  carrying the lock projection  23   b  parallel to the actuation portion  23  with a gap substantially corresponding to the thickness of the recess  17 . The slide portion  24  is a plate-shaped section having a width slightly smaller than the groove width of the cut-out guide opening  17   b  and is formed at its distal end with resilient arm sections  24   a,    24   b,  as shown with a dotted line in FIG. 4. The resilient arm sections  24   a,    24   b  are protruded from the slide portion  24  with an amount of protrusion larger than the groove width of the cut-out guide opening  17   b  on the whole, with the amount of protrusion progressively increasing from the distal end towards the proximal end of the slide section  24 .  
         [0046]    The lock member  13  is assembled to the upper half  2  from the battery pack loading unit side, as the resilient arm sections  24   a,    24   b  are converged, by thrusting the slide portion  24  from its distal end first into the cut-out guide opening  17   b.  On the inner surface of the upper half  2 , the torsion spring  16  has its one end retained by the spring retainer  25  of the lock member  13 . The torsion spring  16  has its coil portion engaged by the rib formed on the inner surface of the upper half  2 , while having its other end retained by the mounting boss section  20 , in the compressed state of the torsion spring  16 , for causing the lock-member  13  to exert the elastic force towards the battery pack loading unit  6 . The lock member  13  is kept in its assembled state by the distal ends of the resilient arm sections  24   a,    24   b,  restored to their natural state, abutting against the inner surface of the cut-out guide opening  17   b.  The lock member  13  is slidably combined with the recess  17 , with the lock projection  23   b  being protruded into the battery pack loading unit  6  as described above.  
         [0047]    The ejection member  14  is formed of synthetic resin as one with an actuation portion  26   a,  a supporting portion  27  and with a supporting shaft  28 , as shown in FIG. 3. The actuation portion  26  is adapted for uplifting the battery pack  60  loaded on the battery pack loading unit  6 , and is of an outer shape substantially corresponding to the shape of the guide opening  19 . In the state in which the ejection member  14  has been mounted to the upper half  2 , the actuation portion  26  is intruded into the guide opening  19  to form a portion of the supporting surface  6   d  of the battery pack loading unit  6 , as shown in FIG. 2. The actuation portion  26  is formed as an inclined surface with its upper surface  26   a  progressively increasing in height from its distal end towards its proximal end, with an increasing amount of protrusion thereof from the supporting surface  6   d  of the battery pack loading unit  6 , as shown in FIG. 2. The actuation portion  26  has its foremost lateral side formed with s protuberant stopper edge  26   b.  In the state in which the actuation portion  26  is intruded into the guide opening  19 , as later explained, the protuberant stopper edge  26   b  abuts against the opening edge of the guide opening  19  to prevent descent of the ejection member  14 .  
         [0048]    The supporting portion  27  is formed on the bottom surface of the actuation portion  26  as a site larger then the guide opening  19  and is formed as one with arm-like projections  27   a,    27   b  towards the proximal end side, as shown in FIGS. 3 and 4. The supporting portion  27  abuts against the opening edge of the guide opening  19  to prevent extrication of the ejection member  14  when the ejection member  14  has been assembled to the upper half  2  from its inner side, with the actuation portion  26  being then intruded from the guide opening  19  into the inside of the battery pack loading unit  6 , as will be explained subsequently. The distal ends of the projections  27   a,    27   b  are formed as one with lugs, not shown, the lateral surfaces of which are formed the supporting shafts  28   a,    28   b.  These supporting shafts  28   a,    28   b  are rotatably carried by bearing units  22   a,    22   b  formed on the inner surface of the upper half  2  with a width-wise separation from each other.  
         [0049]    The ejection member  14  is rotatably carried by the bearing units  22   a,    22   b,  on the inner surface side of the upper half  2 , by the supporting shafts  28   a,    28   b  engaging in the bearing openings from the opened portion. In this state, the ejection member  14  is combined with the upper half  2  by the upper surface  26   a  of the actuation portion  26  engaging in the battery pack loading unit  6  through the guide opening  19 . The ejection member  14  is kept in its assembled state to the upper half  2  by the spring member  15  being mounted to the upper half  2 .  
         [0050]    The spring member  15  is monolithically formed of metal with a proximal portion  29 , an elastic arm  30  and a pair of axial stoppers  31   a,    31   b,  as shown in FIG. 3. The proximal portion  29  is in the form substantially of an isosceles triangle having a bottom side slightly shorter than the width of the upper half  2 . A circular first positioning opening  29   b  and an elongated second positioning opening  29   c  are formed on both sides of a center mounting opening  29   a.  An elastic arm section  30  is protuberantly formed from a site of an apex of the proximal portion  29 . The elastic arm section  30  is formed as one with the proximal portion  29  from near the apex site thereof and has a length sufficient to extend to near the opening edge of the foremost part of the guide opening  19 . The elastic arm section  30  is bent so as to be directed progressively upwards from the proximal portion  29  and has its foremost part arcuately warped downwards to form an abutment portion  30   a  abutting against the bottom of the actuation portion  26  of the ejection member  14 .  
         [0051]    The axial stoppers  31   a,    31   b  are formed as convexed pieces of an L-shaped cross-section extending parallel to the elastic arm section  30  along both sides of the proximal portion  29 . The axial stoppers  31   a,    31   b  are each of a length such that the foremost part of each of the axial stoppers  31   a,    31   b  faces the bearing unit  22 , with the mounting opening  29   a  as reference. The axial stoppers  31   a,    31   b  are bent at the respective foremost parts so as to face each other to form anti-extraction means for the ejection member  14 , as will be explained subsequently in detail.  
         [0052]    In the assembled state of the ejection member  14 , the spring member  15  is mounted to the inner surface of the upper half  2 , as shown in FIG. 4. The spring member  15  has its proximal portion abutted against the inner surface of the upper half  2  as the mounting opening  29   a  is positioned in register with the mounting boss section  20 , the first positioning projection  21   a  is engaged in the first positioning opening  29   b  and as the second positioning projection  21   b  is engaged in the second positioning opening  29   c.  The spring member  15  has its mounting position adjusted within the lengthwise extent of the second positioning opening  29   c  and is subsequently mounted to the upper half  2  by a mounting screw  32  which is threaded to the mounting boss section  20 .  
         [0053]    In this state, the elastic arm section  30  of the spring member  15  is extended towards the guide opening  19 , with the abutment portion  30   a  formed at the forermost part thereof abutting against the bottom surface of the actuation portion  26  of the ejection member  14  for uplifting the actuation portion  26 . On the other hand, the distal ends of the axial stoppers  31   a,    31   b  face the bearing units  22   a,    22   b  for closing the opening site of the bearing holes thereof to prohibiting extrication of the supporting shaft  28  of the ejection member  14  carried by the bearing units  22   a,    22   b.    
         [0054]    Meanwhile, it is possible for the spring member  15  to have not only the function of holding the ejection member  14  as described above but also the function of operating as a holder for other component members assembled to the upper half  2 . The spring member  15  includes a lug  34  formed as one with the bottom side of the proximal portion  29 , as shown for example in FIG. 6. The lug  34  holds a light conducting member  33  mounted to the inner surface of the proximal portion  29 . The light conducting member  33  is formed of, for example, transparent acrylic resin, and is formed as one with projections in association with light emitting elements  33   a,    33   b.  The light conducting member  33  is mounted to the inner surface of the upper half  2  by the proximal portion  29  fitting in the display opening formed in the upper half  2 .  
         [0055]    The spring member  15  is assembled to the ejection member  14  as described above, at the same time as it is mounted to the upper half  2  as the light conducting member  33  is mounted thereto. The spring member  15  thrusts the light conducting member  33  against the inner surface of the upper half  2  to hold it by the lug  34  abutting against the bottom surface of the light conducting member  33 .  
         [0056]    The upper half  2  is formed with a cut-out  2   b,  extending astride the abutment surface  6   a  and the bottom surface  6   d  of the battery pack loading unit  6 , as shown in FIG. 2. In the cutout  2   b  of the upper half  2 , there are provided an electrode block member  35 , forming the electrode unit  7  and the loading detection unit  8 , and a shutter member for protecting the electrode unit  7  and the loading detection unit  8 , as shown in FIG. 7. Referring to FIGS.  8  to  10 , the electrode block member  35  includes a molded frame  37 , a cathode electrode member  38 , forming the electrode unit, an anode electrode member  39  and a communication terminal member  40 , while also including a fixed contact piece  41 , a movable contact piece  42  and an actuation member  43 .  
         [0057]    The electrode block member  35 , having the above-mentioned components, is able to unify the electrode unit  7  and the loading detection unit  8  to each other to achieve high precision positioning and mounting of the electrode block member  35  to the upper half  2 . The electrode block member  35  is thrust from its back side by a spring plate member  44  mounted to the inner surface of the upper half  2 , in a manner free from vibrations, as shown in FIG. 2.  
         [0058]    The molded frame  37  is molded from synthetic resin to substantially a plate shape with a certain thickness on the whole, and is mounted to high precision in the cut-out  2   b  of the upper half  2 , by being formed with a mounting recess for mounting to e.g., a circuit substrate, mounted in position to the lower casing  3 , or with an arm-like protuberant mounting bracket having a mounting opening. The molded frame  37  is divided in two regions in the longitudinal direction, that is into first and second regions in which the electrode unit  7  and the loading detection unit  8  are arranged, respectively.  
         [0059]    The molded frame  37  includes a supporting wall section  37   c,  extending forwards for forming a portion of the supporting surface  6   d  of the battery pack loading unit  6 , and protective ribs  37   a,    37   b  lying on this supporting wall section  37   c  on both sides of the electrode unit  7 . The protective ribs  37   a,    37   b  are formed by wall-shaped projections larger than the outer shape of the electrode members  38  to  40  as later explained. These protective ribs protect the electrode members  38  to  40  while being engaged in the fitting recess  67  of the battery pack  60  for positioning the positioning ribs  9  and the battery pack  60 . The molded frame  37  is formed with an actuation guide  37   e  for slidably assembling the actuation member  43  to the loading detection unit  8 .  
         [0060]    In the electrode unit  7 , the cathode electrode member  38 , anode electrode member  39  and the communication terminal member  40 , formed of metal plates, are insert-molded so that these members face one another with a preset separation from one another and so that the communication terminal member  40  will be arranged at a center position, with the cathode electrode member  38  and the anode electrode member  39  being arranged on its both sides. The cathode electrode member  38 , anode electrode member  39  and the communication terminal member  40  are arranged so that the respective upper and foremost parts are protruded into the inside of the battery pack loading unit  6 . The cathode electrode member  38  and the anode electrode member  39  are connected to the cathode electrode charging terminal member and to the anode electrode charging terminal member loaded in the battery pack loading unit  6 . The communication terminal member is connected to the communication terminal member of the battery pack  60  to exchange the information, such as the specifications information or the charting information, with the battery pack  60 .  
         [0061]    A fixed contact member  41  and a movable contact member  42  are carried by a site of the loading detection unit  8  extending laterally from the electrode unit  7 . Moreover, the actuation member  43 , actuated by the battery pack  60 , is slidably assembled to the loading detection unit  8 . The fixed contact piece  41  and the movable contact piece  42  are fixedly carried at one ends thereof by the molded frame  37  so as to be at right angles to the electrode members  38  to  40  of the electrode unit . 7 , respectively. The fixed contact piece  41  and the movable contact piece  42  face each other in parallel with a preset distance therebetween. At the fixed ends, the terminal unit is passed through the molded frame  37  so as to be protruded towards the bottom. side in the same direction as the terminals of the electrode members  38  to  40 . The fixed contact piece  41  is positioned at the free ends thereof by a stopper projection  37 d protuberantly formed on the molded frame  37 .  
         [0062]    The movable contact piece  42  has its one end secured to the molded frame  37  so that the resilient force will be accumulated in the direction of being separated from the fixed contact piece  41 . The movable contact piece  42  has its free end faced by an actuation portion  43 b of the actuation member  43 , as shown in FIG. 9. In case the battery pack  60  is not loaded in the battery pack loading unit  6 , the movable contact piece  42  is kept in such a state in which the contacts formed on the inner surface of the foremost part thereof are not contacted with the fixed contact piece  41 . Since the force of elasticity is accumulated in the movable contact piece  42 , the movable contact piece  42  is prevented form having inadvertent contact with the fixed contact piece  41  even on application of e.g., vibrations.  
         [0063]    The actuation member  43  is similarly formed unitarily from synthetic resin, such as polybutylene terephthalate. The actuation member  43  in its entirety is substantially plate-shaped and has its foremost part formed with a cam  43   a,  while having its rear part formed as actuation portion  43   b,  in a manner not shown in detail. By the cam  43   a  being thrust by the battery pack  60  loaded in the battery pack loading unit  6 , as will be explained in detail subsequently, the actuation member  43  is slid in a direction parallel to the electrode members  38  to  40  to thrust the movable contact piece  42 . In the state in which the battery pack  60  is not loaded in the battery pack loading unit  6 , the actuation member  43  abuts against the outer lateral surface of the free end of the movable contact piece  42  and hence is subjected to the elastic force stored in the movable contact piece  42 .  
         [0064]    When the actuation member  43  is loaded in the battery pack loading unit  6 , the cam  43   a  is thrust onto the loading surface  60   a  of the battery pack  60 . The actuation member  43  is intruded into the inside of the actuation guide  37   e,  against the force of elasticity of the movable contact piece  42 , so that the movable contact piece  42  is elastically displaced by the actuation portion  43   b  into contact with the fixed contact piece  41  to issue an output detecting the loading of the battery pack  60  in the battery pack loading unit  6 .  
         [0065]    The actuation member  43  causes elastic displacement of the fixed contact piece  41  through the movable contact piece  42 , to maintain the contact state between the fixed contact piece  41  and the movable contact piece  42 , as shown in FIG. 10. On the actuation member  43 , there act the elastic force, indicated by arrow B, and the elastic force, indicated by arrow C, as shown in FIG. 10.  
         [0066]    A shutter member  36  is formed of a synthetic resin material to an arcuate cross-section The shutter member is located below the stopper projection  10 , and has its upper portion rotatably supported by the inner surface of the upper half  2 . Although not shown, a spring is mounted on a support shaft of the shutter member  36  for biasing it clockwise in FIG. 7. When the battery pack  60  is not loaded in the battery pack loading unit  6 , the shutter member  36  is kept in such a state in which it covers the electrode members  38  to  40  to protect these electrode members as well as to prevent dust and dirt from becoming deposited thereon. When the battery pack  60  is loaded in the battery pack loading unit  6 , the shutter member  36  is rotated to expose the electrode members  38  to  40  to outside.  
         [0067]    Referring to FIGS.  11  to  14 , the operation of loading the battery pack  60  to the battery pack charging device  1  and of ejecting it therefrom is explained. The battery pack  60  is loaded into the battery pack loading unit  6  from the loading surface  60   a,  as the battery pack is slightly tilted relative to the upper surface  2   a  of the upper half  2 , as indicated by arrow in FIG. 11. The battery pack  60  is positioned in such a manner that, as the loading surface  60   a  of the battery pack  60  is abutted against the abutment surface  6   a  of the battery pack loading unit  6 , as indicated by a chain-dotted line in FIG. 11, the stopper projection  14  is engaged with the fitting recess  67  to hold the loading surface side, with the positioning rib  9  engaging with the positioning recess  64 , for positioning the battery pack  60 .  
         [0068]    In the battery pack charging device  1 ,when the battery pack  60  descends in the battery pack loading unit  6 , with the lock surface  60   b  first, the lock member  13  is slid within the recess  17 , against the force of the torsion spring  16 , under the thrust exerted by the lock surface  60   b.  When the stopper projection  23   a  is slid on the lock surface.  60   b  until facing the lock recess  66 , the lock member  13  is slid under the elastic force of the torsion spring  16 , whereby the stopper projection  23   a  is engaged with the lock recess  66 .  
         [0069]    In the battery pack charging device  1 , the ejection member  14  is rotated clockwise in FIG. 12, about the supporting shafts  28   a,    28   b  as the fulcrum, as a consequence of the actuation portion  26  being thrust by the battery pack  60  loaded in the battery pack loading unit  6 . Thus, the actuation portion  26  is thrust inwards from the guide opening  19 . By the stopper projection  26   b  abutting against the opening edge of the guide opening  19 , the actuation portion  26  is substantially flush with the supporting surface  6   a  of the battery pack loading unit  6  to support the bottom surface  60   d  of the battery pack  60 . The ejection member  14  during its rotation causes downward resilient movement of the elastic arm section  30  of the spring member  15  applied to its inner side. To the ejection member  14 , there is applied the elastic force operating in the counterclockwise direction from the spring member  15  in FIG. 12.  
         [0070]    When the battery pack charging device  1  is loaded in the battery pack loading unit  6 , its loading surface  60   a  of the battery pack  60  is held by the stopper projection  14 , while its lock surface  60   b  is held by the lock member  13 . In the battery pack charging device  1 , the elastic force of the spring member  15  is applied to the bottom surface  60   d  of the battery pack  60 , through the ejection member  14 , while the elastic force of the fixed contact piece  41  and the movable contact piece  42  is applied to the loading surface  60   a  through the actuation member  43 .  
         [0071]    When the charging operation for he battery pack  60  by the battery pack charging device  1  has come to a close, the lock member  13  is slid towards left in the recess  17  in FIG. 13 against the force of the spring member  15 . With the lock member  13 , thus slid, the stopper projection  23   b  of the actuation portion  23  is extricated from the lock recess  66  to unlock the lock surface  60   b  of the battery pack  60 . In the battery pack charging device  1 , the actuation portion  26  is protruded via guide opening  19  into the inside of the battery pack loading unit  6 , under the force of the spring member  15 , as shown in FIG. 13. The ejection member  14  uplifts the lock surface  60   b  of the battery pack  60 , as indicated by arrow in FIG. 11.  
         [0072]    In the battery pack charging device  1 , the elastic force of the fixed contact piece  41  and the movable and the contact piece  42  is applied to the loading surface  60   a  of the battery pack  60  through the actuation member  43 . By the side of the lock surface  60   b  being opened, the battery pack  60  is thrust by the actuation member  43  in a direction indicated by arrow in FIG. 13. This causes the battery pack  60  to be moved in its entirety in the battery pack loading unit  6  towards the lock/eject mechanism  11 , as indicated by arrow in FIG. 14. In the battery pack charging device  1 , the charging terminal unit  63  is separated from the electrode unit  7 , by such movement of the battery pack  60 , as shown in FIG. 14. In the battery pack charging device  1 , the shutter member  36  is restored to its initial position to keep the electrode unit  7  and the charging terminal unit  63  separated from each other.  
         [0073]    In the battery pack charging device  1 , the operation of the actuation member  43  in causing the movement of the battery pack  60  towards the lock/eject mechanism  11  by the actuation portion  26  being rotated in sliding contact with the bottom surface  60   d  of the battery pack  60 .