Abstract:
A replaceable, stand-alone charging apparatus for insertion into a portable electronic device having an energy storage device and a rechargeable battery that supplies energy to the energy storage device is provided. The replaceable, stand-alone charging apparatus has a body and a battery charging device housed substantially with the body and operable to charge the rechargeable battery of the portable electrical device. The replaceable, stand-alone charging apparatus further has an electrical connector adapted for connection with a cooperative electrical connector coupled to the rechargeable battery of the portable electronic device. The electrical connector is in electrical communication with the battery charging device.

Description:
FIELD OF THE INVENTION 
     The present invention is directed to charging packs for recharging a power source of a portable electronic device, and more particularly, to charging packs for recharging the power source of portable external defibrillators. 
     BACKGROUND OF THE INVENTION 
     The current trend in the medical industry is to make life-saving portable medical devices, such as portable external defibrillators, more widely accessible to non-medical personnel. As the availability of portable medical devices increases, it is expected that more places will have these devices for use in emergency situations, such as in homes, police cars, worksites, and public gathering places. 
     There are several types of known portable external defibrillators, some of which are commonly referred to as automatic and semi-automatic defibrillators. An automatic defibrillator monitors and analyzes electrocardiogram (ECG) of the patient once the electrodes of the defibrillators are connected to a patient and, based on the ECG analysis, automatically delivers a defibrillation shock to the patient through the electrodes without user intervention. On the other hand, semi-automatic defibrillators operate such that once the ECG analysis indicates that defibrillation is recommended, an operator is prompted to manually trigger delivery of a defibrillation shock to the patient by depressing a triggering mechanism, such as a shock button. In either case, the portable external defibrillator must contain or be connected to an energy source to generate and apply a defibrillation pulse to the fibrillating patient. To ensure true portability, most portable external defibrillators are constructed with a removable battery pack, which rests within a battery well positioned in the defibrillator body. The battery pack is constructed to supply sufficient power to operate the portable external defibrillator for a period of time. The battery pack may be either rechargeable or non-rechargeable, depending on the user&#39;s preference and the environment in which the defibrillator is to be used. One such battery pack is described in U.S. Pat. No. 5,868,790 to Vincent at el., and is presently assigned to Medtronic Physio-Control Manufacturing Corporation of Redmond, Wash. 
     While battery packs are successful in their present application, the overall configuration of utilizing removable battery packs as the power source of portable external defibrillators poses several deficiencies. For instance, as is well known in the art, a portable external defibrillator is unusable as a medical treatment device without the battery pack or with a battery pack that is discharged. In most situations, changing or recharging the battery pack will typically occur during normal testing of the defibrillator in a non-emergency setting. In the case of recharging the battery pack, a separate charging station is required, which is sometimes prohibitively expensive. If the user does not have a charging station, the user must have the battery pack charged and conditioned by a servicing center, prior to which time the portable external defibrillator is without a power source and will not operate if needed. To remedy this situation, additional battery packs must be purchased, which increases the overall operating costs associated with operating portable external defibrillators. 
     Additionally, a current user may have to change the battery pack at the site of the emergency. For example, a prior user of the defibrillator may have left a discharged battery pack in the device that is not discovered until treatment is to be initiated on a patient. Alternatively, the defibrillator could be in use when the battery pack becomes discharged, requiring the current user to replace the battery pack before continuing treatment. In either case, replacing the discharged battery pack with a charged battery pack increases the total time required to deliver treatment to the patient. Furthermore, these additional battery packs must also be purchased and charged, which again, increases the overall cost of operating the portable external defibrillator. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to a selectively removable charging pack that is operable to recharge the power source of a portable external defibrillator when coupled thereto, so as to overcome the deficiencies of the prior art. 
     In accordance with one embodiment of the present invention, a replaceable, stand-alone charging apparatus is provided for insertion into a portable electronic device having an energy storage device and a rechargeable battery that supplies energy to the energy storage device. The charging apparatus comprises a body and a battery charging device housed substantially within the body and operable to charge the battery of the portable electrical device. The charging apparatus further comprises an electrical connector adapted for connection with a cooperative electrical connector coupled to the rechargeable battery of the portable electronic device. The electrical connector is in electrical communication with the battery charging device. 
     In accordance with another embodiment of the present invention, a replaceable, stand-alone charging apparatus is provided that is capable of connection to a portable external defibrillator having an energy storage device and a rechargeable battery that supplies energy to the energy storage device. The charging apparatus comprises a body and a battery charging device housed substantially within the body and operable to charge the rechargeable battery of the portable external defibrillator. The charging apparatus further comprises a latch, which is disposed at approximately one end of the body. The latch is movable between an extended position and a retracted position. The latch is biased in the extended position. 
     In accordance with still another embodiment of the present invention, a portable, stand-alone insertable charging pack for charging a battery substantially affixed to a portable external defibrillator and supplying energy to an energy storage device of the portable external defibrillator is provided. The charging pack comprises a body having proximal and distal ends. The body is formed by a base portion and a cover portion. A battery charging device is provided that is positioned within the base portion and operable to charge the battery of the portable external defibrillator. The charging pack further comprise a latch formed from a portion of the cover and located at the distal end of the body. The latch is movable between an extended position and a retracted position, and is biased in the extended position. When the charging pack is partially inserted into the portable external defibrillator, the latch moves to the retracted position. The latch returns to the extended position after the charging pack is fully inserted in a portable external defibrillator. 
     In accordance with still yet another embodiment of the present invention, a portable, stand-alone charging apparatus is provided that is capable of connection to a portable external defibrillator having an energy storage device and a rechargeable battery that supplies energy to the energy storage device. The charging apparatus comprises a body and means for charging the rechargeable battery of the portable external defibrillator. The means for charging is disposed within the body. The charging apparatus also comprises means for transferring power from the charging means to the rechargeable battery of the portable external defibrillator. 
     In accordance with still yet another embodiment of the present invention, a portable external defibrillator device of the type having a body which houses defibrillator components comprising defibrillator circuitry, an energy storage device and a rechargeable battery for supplying energy to the energy storage device is provided. The improvement thereto comprises a charging well provided in the body of the portable external defibrillator and a charging apparatus selectively removable from within the charging well. The charging apparatus comprises a body having a battery charging device operable to charge the rechargeable battery of the portable external defibrillator device. The charging apparatus further comprises an electrical connector coupled to the body of the charging apparatus and in electrical communication with the battery charging device. 
     In accordance with yet still another embodiment of the present invention, a portable external defibrillator system is provided. The portable external defibrillator system comprises defibrillator circuitry, an energy storage device and a rechargeable battery that provides energy to the energy storage device, and a body for housing the defibrillator circuitry. the energy storage device and the rechargeable battery. The portable external defibrillator system also comprises a selectively removable charging apparatus that comprises a body having a battery charging device operable to charge the rechargeable battery of the portable external defibrillator system. The charging apparatus further includes a latch that is movable between an extended position and a retracted position. The latch is biased in the extended position. The portable external defibrillator system further includes a charging well provided in the body of the defibrillator into which the selectively removable charging apparatus is inserted. The charging well includes a side wall, a portion of which is operable to contact the latch of the charging apparatus as the charging apparatus is inserted into the charging well. 
     In accordance with yet a further embodiment of the present invention, a portable external defibrillator system is provided. The portable external defibrillator system comprises defibrillator circuitry, an energy storage device and a rechargeable battery that supplies energy to the energy storage device, and a body for housing the defibrillator circuitry, the energy storage device and the rechargeable battery. The portable external defibrillator system also comprises a selectively removable charging apparatus that comprises a charging apparatus body and a battery charging device operable to charge the rechargeable battery of the portable external defibrillator system. The portable external defibrillator system also comprises a charging well provided in the defibrillator body into which the removable charging apparatus is inserted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a top perspective view of one embodiment of a portable external defibrillator formed in accordance with the present invention, illustrating a charging pack selectively removed from a charging well; 
         FIG. 2  is a top perspective view of the portable external defibrillator of  FIG. 1 , illustrating the charging pack partially inserted into the charging well; 
         FIG. 3  is a bottom front perspective view of one embodiment of a charging pack constructed in accordance with the present invention; 
         FIG. 4  is a rear view of the charging pack of  FIG. 3 ; 
         FIG. 5  is a top rear perspective view of the charging pack of  FIG. 3 ; 
         FIG. 6  is a longitudinal cross-section view of the charging pack of  FIG. 3 ; 
         FIG. 7A  is a partial cross-section view of a schematic representation of the portable external defibrillator of  FIG. 1  showing the charging pack of  FIG. 3  within the charging well; 
         FIG. 7B  is a partial cross-section view of a schematic representation of another embodiment of a defibrillator charging pack inserted into a portable external defibrillator for aiding in securing the top housing section of the portable external defibrillator to the bottom housing section of the portable external defibrillator. 
         FIG. 8  is a partial cut-away view of the portable external defibrillator shown in  FIG. 2 , having the charging pack of  FIG. 3  inserted therein; and 
         FIGS. 9 ,  10  and  11  are cross-section views of the charging pack and charging well, depicting the operation of a latch to secure the charging pack within the charging well. 
         FIG. 12  is a schematic block diagram showing electrical components, with the housings for the charge pack and defibrillator shown in phantom. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     While the present invention was developed to re-charge a power source (e.g., a battery) located in a portable external defibrillator, it is to be understood that the invention can be used in other electrical devices requiring or desiring battery charging capability, such as cordless tools and portable appliances. Thus, the following description relating to portable extended defibrillators is meant to be illustrative and not limiting to the broadest scope of the inventions, as claimed. 
     Prior to describing an exemplary embodiment of a charging pack, a brief discussion of the nature and operation of one type of portable external defibrillator suitable for incorporating the present invention is set forth. In this regard, attention is directed to  FIGS. 1-2 , which illustrate selected components of a portable external defibrillator  20 . Generally described, the portable external defibrillator  20  includes a housing  22  and a lid  24 . The lid  24  is pivotally coupled to the housing  22  so that the lid  24  can be opened to reveal a defibrillator control panel having defibrillator components, such as a shock button. The housing  22  is formed by top and bottom housing sections  22 A and  22 B such that when assembled, the housing sections mate to form a shell to house all of the electrical components of the defibrillator  20 . The housing sections  22 A and  22 B are connected together by any known mechanical fastener, such as snap-lock assemblies or screws. As will be described in more detail below, one embodiment of a charging pack is described that aids in securing the housing sections together. 
     The electronic components of the defibrillator  20  include, but are not limited to, a controller, a charging circuit, an energy storage device, and an output circuit. These components (shown in block form in  FIG. 12  as defibrillator circuitry) are typically utilized in conventional defibrillators, and thus will not be described in any more detail. Power for the defibrillator  20  is provided by a power source (see  FIG. 12 ) in the form of rechargeable cells securely located within the housing  22  of the defibrillator  20 . The electrical components of the defibrillator  20  also include a selectively removable charging pack  60  mounted within a charging well  140  of the defibrillator  20 . When placed within the charging well  140 , the charging pack  60  is operable to recharge the power source so that the defibrillator  20  may deliver the requisite charge. While in the embodiment shown the charging pack  60  is inserted into the charging well  140  of the defibrillator  20 , it will be apparent that the defibrillator  20  and charging pack  60  may be configured so that the charging pack  60  can be coupled externally to the defibrillator  20 , if desired. 
     To facilitate use, the defibrillator  20  may be formed from impact-resistant plastic and includes an integral handle  26  to allow the user to easily carry the defibrillator to the desired location. In operation, the defibrillator  20  is preferably positioned so that the control panel (hidden by the lid  24 ) is oriented upwards toward the user. The control panel contains a user interface that allows the user to operate the defibrillator after the defibrillator is connected to the patient via a pair of electrodes (not shown). As is well known in the art, under the control of the controller, the charging circuit transfers energy from the power source to the energy storage device, and the output circuit transfers energy from the energy storage device to the electrodes. In the case of a semi-automatic version of the defibrillator, a shock key is depressed by the operator to trigger application of a defibrillation shock to the patient. 
     One suitable embodiment of a charging pack  60  formed in accordance with the present invention is illustrated in  FIGS. 3-6  and comprises an elongate body of generally triangular shaped cross section having a front region  62 , a back region  64 , a top region  66 , and left and right sides  70  and  72 , that form a bottom region  74  at the convergence of left and right sides. The front region  62  of the charging pack is formed with a latch  120  which may be utilized by a user to remove the charging pack from the defibrillator. As will be discussed in detail below, the latch  120  automatically secures the charging pack  60  in the charging well when the charging pack  60  is inserted into the defibrillator. The front region  62  of the charging pack  60  is suitably formed so that when the charging pack  60  is inserted into the defibrillator, the front region  62  of the charging pack  60  is substantially flush with the side of the defibrillator. The front region  62  may also include ridges  76  disposed on the front surface of the charging pack  60  that provide gripping surfaces for a user&#39;s fingers when the charging pack  60  is pushed into place within the charging well. 
     As best shown in  FIGS. 3 and 4 , the bottom region  74  of the charging pack  60  includes an in-cut ridge  80  that is formed into the bottom surface of the charging pack  60  and extends along the length of the charging pack. As will be described in more detail below, the ridge  80  is disposed within a slot formed by the flange members of the housing sections when the charging pack  60  is inserted into the charging well of the defibrillator. Accordingly, the ridge  80  of the charging pack  60  aids in securing the housing sections together. 
     In accordance with one aspect of the present invention, the charging pack aids in securing the top housing section to the bottom housing section.  FIG. 7A  is a partial side view of a schematic representation of the defibrillator  20  depicting the charging well  140 . As shown in  FIGS. 1 and 7A , the charging well  140  is positioned at the front of the defibrillator  20  and is formed by the mating of the housing sections  22 A and  22 B. The top housing section  22 A includes flange members  40  that are spaced-apart and extend along the longitudinal axis of the charging well  140 . Similarly, the bottom housing section  22 B includes flange members  42  that are spaced-apart and extend along the longitudinal axis of the charging well  140 . The flange members  40  and  42  are disposed at the front of the charging well and protrude slightly into the charging well  140 . The flanges  40  and  42  are adapted to mate as interlocking fingers, which define a slot  44  for receiving the ridge  80  of the charging pack  60 . When the charging pack is inserted into the charging well, the ridge  80  of the charging pack  60  slides into the slot  44  formed by the flange members  40  and  42 . Once the charging pack  60  is fully inserted into the charging well  140 , the ridge  80  of the charging pack  60  prevents the top housing section  22 A from separating from the bottom housing section  22 B, as shown in  FIG. 7A . 
       FIG. 7B  is a partial cross-section view of a schematic representation of another embodiment of a defibrillator charging pack inserted into a portable external defibrillator for aiding in the securement of the top housing section to the bottom housing section. The construction and operation of the defibrillator  200  and charging pack  260  are similar to that of the defibrillator  20  and charging pack  60 , respectively, except for the differences that will now be described in detail. As best shown in  FIG. 7B , the ridge of the charging pack shown in FIGURES is replaced by spaced-apart flange members  282 A and  282 B. The spaced-apart flange members extend outwardly away from the bottom surface of the charging pack  260 , along its length. The space formed between the flange members defines a slot  284 . In this embodiment, the top housing section  222 A include a flange member  242 A that extends along the longitudinal axis of the charging well  140 . Similarly, the bottom housing section  222 B include a flange member  242 B that extends along the longitudinal axis of the charging well  240 . The flange member  242 A and  242 B are disposed at the front of the charging well and protrude slightly into the charging well  240 . The flanges  242 A and  242 B are adapted to either contact or be disposed adjacent to one another when assembled as shown in  FIG. 7B . 
     When the charging pack  260  is inserted into the charging well  240 , the flange members  242 A and  242 B of respective housing sections  222 A and  222 B slide into the slot  284  formed by the spaced-apart flange members  282 A and  282 B of the charging pack  260 . Once the charging pack  260  is fully inserted into the charging well  240 , the space-apart flange members  282 A and  282 B of the charging pack  260  prevent the top housing section  222 A from separating from the bottom housing section  222 B, as shown best in  FIG. 7B . 
     Referring back to  FIGS. 3 ,  4  and  5 , the back region  64  of the charging pack  60  includes a shelf portion  84  and an upright portion  86 . The shelf portion includes a socket  88  disposed in the longitudinal direction of the charging pack  60 . The socket  88  contains a conductive set of pins  90  that are electrically connected to charging cells  110  (shown in  FIG. 6 ) located within the charging pack  60 . Locating the conductive pins  90  within the socket  88  minimizes the likelihood that the user will inadvertently come into contact with the conductive pins. In the embodiment shown, the upright portion  86  is constructed orthogonal to the protruding shelf portion  84  to provide a flat surface to which a biasing member engages when the charging pack is positioned within the charging well of the defibrillator. 
     As shown in  FIG. 5 , the top region  66  of the charging pack  60  is substantially planer and maybe formed with a recessed region (not shown). The recessed region allows a label to be affixed to the top region  66  of the charging pack  60  without protruding above the top surface of the charging pack  60 . The label may contain general information identifying the type of charging cells, a “use by” date, a part number, and date code, to name a few, if desired. 
     The internal construction of the charging pack  60  will be better appreciated with respect to the cross-sectional view of  FIG. 6 . As shown in  FIG. 6 , the body of the charging pack  60  is generally comprised of a cover  100  and a base  102 . The cover  100  and base  102  are preferably formed of an injection-molded plastic and secured together via any conventional method, e.g., ultrasonic welding or adhesive bonding. It will be appreciated by those skilled in the art, however, that the cover  100  and base  102  may be formed of other materials. In the embodiment shown, the cover  100  is an elongate member that is substantially plate-like, and is positioned such that when secured to the base  102 , forms the top region  66  of the charging pack  60 . 
     The base  102  is generally V-shaped in cross section, and includes an inner upstanding wall  106  that, in conjunction with the back region  64  of the charging pack  60 , defines an interior cavity  108 . Mounted within the interior cavity  108  are a plurality of charging cells  110  held into place via molded structures in the base  102 . The charging cells  110  can be either rechargeable or non-rechargeable cells, which are well know in the art and will not be described in further detail. The charging cells  110  are electrically connected in a conventional manner to a circuit board  112  mounted below the cover  100 . Connected to the circuit board  112  in electrical communication with the charging cells  110  is the set of pins  90 . The set of pins  90  define an electrical connector (see  FIG. 12 . element a) that mates with a corresponding electrical connector (see  FIG. 12 . element b) mounted within the charging well of the defibrillator. In the embodiment shown, the set of pins  90  protrudes downwardly into the socket  88  of the shelf portion  84 . 
     While the electrical connector of the charging pack  60  has been described above and illustrated herein as a set of pins, it will be apparent to those skilled in the art that the electrical connector may be any known electrical connector operable to electrically connect the charging pack to the portable external defibrillator. Additionally, it will be appreciated to those skilled in the art that the placement of the electrical connector shown in the FIGURES is just one of the many possible locations for the electrical connector, and therefore should not be construed as limiting the present invention. 
     The base  102  also includes an outer upstanding wall  114  spaced apart from the inner upstanding wall  106  and remote from the interior cavity  108 . The outer upstanding wall  114  extends from the bottom surface of the charging pack to just proximate the cover  100  to form the front surface of the charging pack  60 . A space  116  is created between the bottom surface of the cover  100  and the top edge of the outer upstanding wall  114  so that a front portion  118  (having a smaller width dimension as the top of the base shown in  FIG. 5 ) of the cover  100  is cantilevered about the inner upstanding wall  106 . The amount of space created is designed such that the front portion  118  is prevented from over-traveling, which may cause damage to the latch. The inner wall  106  supports the cover  100 . As described above, the outer upstanding wall  114  includes outwardly extending spaced-apart ridges  76  that provide a gripping surface to a user&#39;s finger when the charging pack  60  is pushed into place within the charging well. 
     Referring now to  FIGS. 5 and 6 , the latch  120  is formed by the cantilevered portion of the cover  100  and includes an actuation member in the form of a tab  122 . The latch  120  is operable to secure the charging pack  60  within the charging well of the defibrillator. In the embodiment shown, the latch  120  includes a latch member  124  that engages with a slot disposed in the charging well of the defibrillator, as will be described in detail below. The latch member  124  includes a inclined leading face  128  (shown in  FIG. 6 ) and a trailing face  130 . The latch member  124  protrudes outwardly from the top surface of the charging pack  60  when in an extended position. Downward movement of the latch tab  122  causes a corresponding downward movement of the latch member  124 , thereby retracting the latch member  124  below the top surface of the charging pack  60 . 
     Referring to  FIGS. 7 and 8 , the charging well  140  of one type of portable external defibrillator  20  briefly described above will now be described in detail. The geometry of the charging well  140  in cross section corresponds with the outer cross-sectional geometry of the charging pack  60  and is dimensioned slightly greater than the charging pack  60  so that the charging pack  60  is keyed to the charging well  140  of the defibrillator  20 . This assures proper alignment of the charging pack  60  as the charging pack  60  is inserted into the charging well  140 . The keying feature also prevents incorrect insertion of the charging pack  60  into the defibrillator  20 . The depth of the charging well  140  is of suitable dimension so that the charging pack  60  nests entirely within the charging well  140 , the front surface of the pack  60  being flush with the side of the defibrillator  20 . 
     Referring to  FIGS. 8 and 9 , the charging well  140  includes an upstanding side wall  144  that is positioned adjacent to the top surface of the charging pack  60  when the charging pack is inserted. As best shown in  FIGS. 9-11 , the side wall  144  is formed with a slot  148 . The slot  148  is suitably dimensioned to receive the latch portion  124  of the charging pack  60  when the charging pack  60  is completely inserted into the charging well  140 . Located outwards of the slot  148  is an outer wall portion  150  of the side wall  144 , which will engage with the latch portion  124  when the charging pack  60  is inserted into the charging well  140 . 
     While the latch  120  of the charging pack  60  has been described above and illustrated herein to include a latch member for securing the charging pack  60  within the charging well, it will be apparent to those skilled in the art that the latch  120  may have alternative configurations for securing the charging pack within the charging well. In one embodiment, the latch  120  may omit the latch member  124 . In this embodiment, the latch may be configured such that when inserted, the friction generated between the top surface of the latch  120  and the side wall  144  of the charging well  140  retains the charging pack  60  therein. Alternatively, the latch  120  may include a slot instead of the latch member  124 . In this embodiment, the side wall  144  of the charging well  140  is provided with a latch member similar to that of latch member  124  described above for engagement within the slot of the latch  120 . 
     Referring now to  FIG. 8 , the charging well further includes an electrical connector  160  and a biasing member  162  mounted at the rear of the charging well. The electrical connector  160  is adapted to connect with the set of pins  90  (shown in  FIG. 4 ) positioned within the socket of the charging pack  60 . The biasing member  162  engages the upright portion  86  of charging pack  60  when the charging pack  60  is fully inserted into the charging well  140 . 
     When the charging pack  60  is nearly fully inserted into the charging well  140 , the electrical connector  160  mounted at the rear of the charging well  140  is received by the socket  88  (shown in  FIG. 5 ) in the shelf portion  84  of the charging pack  60 . While the connector  160  mounted at the rear of the charging well  140  is received by the socket in the back of the shelf portion  84 , the upright portion  86  of the charging pack  60  pushes against the biasing member  162  of the charging well  140 , placing the biasing member  162  in a loaded or cocked position. The electrical connector  160  is specifically designed to mate with the conductive pins  90  (shown in  FIG. 4 ) in the charging pack  60 . The construction of the charging well  140  and the charging pack  60  ensure that the mating of the corresponding pins is automatically performed as the charging pack  60  is inserted fully into the charging well  140 , without requiring the user to align the charging pack. The alignment provided by this mating feature ensures that the pins on the charging pack  60  will not be broken or bent as the charging pack  60  is inserted into the defibrillator  20 . 
     Referring now to  FIGS. 9-11 , to prevent the charging pack  60  from falling out of the charging well once it has been inserted, latch  120  is designed to automatically secure the charging pack  60  within the charging well  140 . As the charging pack  60  is slid into the charging well  140 , as shown in  FIG. 9 , the leading face  128  of the latch member  124  comes into contact with the outer wall portion  150  of the side wall  144 . The leading face  128  of the latch member  124  is angled so that as the charging pack  60  is further inserted into the charging well  140 , the latch member  124  is automatically forced in the direction of the bottom  74  of the charging pack  60  as the leading face  128  contacts the outer wall portion  150  of the side wall  144 , as shown in  FIG. 10 . A user therefore does not have to move latch  120  when inserting the charging pack  60 , since the displacement of the latch member  124  is automatically performed. 
     Referring now to  FIG. 10 , as the charging pack  60  nears the position illustrated, the latch member  124  continues to travel along the outer wall portion  150 . Again, the angled leading surface  128  of the latch member  124  causes the latch  120  to move as the latch member  124  travels along the outer wall portion  150 . After traveling along the outer wall portion  150 , the latch member  124  is forced into the slot  148  by the biasing action of the cantilevered latch  120 , as best shown in  FIG. 11 . As will be appreciated by those skilled in the art, the cover  100  ( FIG. 6 ) that forms the latch  120  is constructed from a suitable material such that when the latch  120  is displaced, the cover  100  creates a sufficient biasing force to return the latch  120  to the non-displaced or extended position. When the latch member  124  is captured in the slot  148 , the trailing face  130  of the latch member  124 , which is generally flat, is brought into contact with the flat outward side of the slot  148 . The contact between the latch member  124  and the flat outward side of slot  148  secures the charging pack  60  in place, and prevents the charging pack  60  from becoming separated from the defibrillator  20 . 
     To remove the charging pack  60 , a user must apply a force in the direction of the bottom of the charging pack  60  onto tab  122  to retract the latch member  124  from the slot  148 . Displacing the tab  122  lowers the latch member  124  so that the trailing face  130  of the latch member  124  clears the flat outward side of the slot  148 . As the tab  122  is displaced, the charging pack  60  is automatically thrusted outwardly from the defibrillator  20  due to the biasing force of the loaded or cocked biasing member  162  (shown in  FIG. 8 ) against the back upright portion  86  of the charging pack  60 . Once the latch member  124  clears the flat outward side of the slot  148 , the user may return the latch  120  to the extended position. 
     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention. For example, the number of charging cells can vary depending on the required operation voltage of the defibrillator. Additionally, while the charging pack was shown having a generally triangular cross section, other cross-sectional geometries, such as circular or rectangular to name a few, are to be within the scope of the present invention. It will be appreciated that as the cross-sectional geometry of the charging pack changes, the shape of the charging well may also change accordingly. Further, the electrical connector is shown at the rear of the charging pack; however, it may be located anywhere on the body, as desired.