Patent Publication Number: US-2007096690-A1

Title: Charger system for cordless power devices

Description:
PRIORITY STATEMENT  
      This U.S. non-provisional patent application claims priority to provisional application 60/731,270, filed Oct. 31, 2005, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND  
      Example embodiments relate generally to a battery charger for cordless power tools.  
     DESCRIPTION OF RELATED ART  
      Cordless products which use rechargeable batteries are prevalent throughout the workplace as well as in the home. From house wares to power tools, rechargeable batteries are used in numerous devices. Ordinarily, nickel-cadmium, nickel metal-hydride and/or Lithium-ion battery cells are used in these devices. The devices typically use a plurality of battery cells, which may be packaged as battery packs. These battery packs may be coupled with the cordless devices and secured to the device. The battery pack may be removed from the cordless device and charged in a battery charger or charged in the cordless device itself.  
      As most cordless devices employ the use of battery chargers to recharge the battery packs, the design of the battery charger should be simple and easy to manufacture. Moreover, as the use of such batteries in our daily life is becoming more and more common, charging of rechargeable batteries and reliability of charging units are becoming significant. For instance, the design and manufacturing of these charging units should be simple and ergonomic. However, most charging units are merely used to charge batteries and stored away when the batteries are fully charged. Accordingly, there exists a need to replace the conventional charging unit with a charging unit that is multi-purpose or versatile, e.g., perform other functions.  
     SUMMARY  
      In accordance to an example embodiment, a battery charger is disclosed. The battery charger may include a housing formed by an upper housing half-shell and a lower housing half-shell connected together so that the half-shells align with one another, an opening for inserting a battery pack, and an electrical cord extending form the housing. The upper and lower housing half-shells each may include an indent area, wherein the indent areas are in alignment with one another so that the electrical cord wraps around and occupies the indent areas.  
      In accordance with another example embodiment, a battery charger may include a housing formed by an upper housing half-shell and a lower housing half-shell connected together so that the half-shells align with one another. The lower housing half-shell may include a plurality of connectors to retain a printed circuit board (PCB) therein, and an electrical cord extending from the housing.  
      In accordance to another example embodiment, a battery charging unit may include a housing having an upper shell housing and a lower shell housing formed with a longitudinally extending parting line, and an opening for inserting a battery pack, wherein the upper shell housing including at least one linear blade retention area for holding a blade.  
      In accordance to another example embodiment, a battery charging unit may include a housing having an upper shell housing and a lower shell housing formed with a longitudinally extending parting line, and an opening for inserting a battery pack, wherein the upper shell housing including at least one linear blade retention area for holding a blade.  
      In accordance to another example embodiment, a battery charging unit may include a housing having an upper shell housing and a lower shell housing formed with a longitudinally extending parting line, and an opening for inserting a battery pack, wherein the housing including a note pad on a top surface of the upper shell housing.  
      In accordance to another example embodiment, a battery pack may include a LED light indicator on a top surface of the battery pack for indicating a status of the battery pack. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The present invention will become more apparent by describing, in detail, exemplary embodiments thereof with reference to the attached drawings, wherein like elements are represented by like reference numerals, which are given by way of illustration only and thus do not limit the example embodiments.  
       FIG. 1  is a schematic view of a battery charger in accordance with an exemplary embodiment of the present invention.  
       FIG. 2  is a schematic view of a battery charger in accordance with an exemplary embodiment of the present invention.  
       FIGS. 3 through 5  are side views of the charger in accordance with exemplary embodiments of the present invention.  
       FIG. 6  is a schematic view of a battery charger in accordance with another exemplary embodiment.  
       FIG. 7  is a schematic view of a battery pack and a battery charger in accordance with an exemplary embodiment.  
       FIG. 8  is a schematic view of a lower housing half-shell of the housing in accordance with an exemplary embodiment. 
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS  
      It should be noted that these Figures are intended to illustrate the general characteristics of the exemplary embodiments of the present invention, for the purpose of the description of such exemplary embodiments herein. These drawings are not, however, to scale and may not precisely reflect the characteristics of any given embodiment, and should not be interpreted as defining or limiting the range of values or properties of exemplary embodiments within the scope of the exemplary embodiments of the present invention. The relative dimensions and size of the cordless device, battery pack and/or battery charger may be reduced or exaggerated for clarity. Like numerals are used for like and corresponding parts of the various drawings.  
      As used herein, power tools may be understood as a cordless power tool with the use of light-weight portable power sources, such as, but not limited to, lithium-ion (Li-ion) battery packs that may provide the commensurate power with its use.  
      The battery pack may include a plurality of battery cells disposed within a housing of the battery pack. The battery pack may be embodied as at least one of a lithium ion (Li-ion), a nickel cadmium (NiCd), a nickel metal hydride (NiMH) and a lead-acid battery pack, for example, in terms of the chemistry makeup of individual cells, electrodes and electrolyte of the battery pack. The battery cells may be connected in series and/or parallel.  
       FIG. 1  is a schematic view of a battery charger in accordance with an exemplary embodiment. Referring to  FIG. 1 , the battery charger  1  includes a housing  10  formed by a lower housing half-shell  20  and an upper housing half-shell  30 . The lower and upper half-shells  20 ,  30  may be formed by injection-molded plastics. A printed circuit board (PCB) (shown in  FIG. 8 ) is disposed within housing  10  essentially extending parallel to the housing bottom. The PCB supports electrical components thereon. The upper housing half-shell  30  includes a plurality of slots or vents  45  on an upper edge surface of the upper housing  30  for ventilation, an LED indicator  47  for indicating the status of the battery charge, and an opening  50  for receiving the rechargeable battery to be inserted. The opening  50  can be dimensioned to fit a Li-ion battery pack, for example. Conductive terminals (not shown) may be provided in the opening  50  for interconnecting between the battery and a charger circuit for charging purposes and electrical communications.  
      It should be appreciated that the lower housing half-shell  20  may include additional openings or vents for additional ventilation.  
      It should further be appreciated that heat sink(s) may be included in the housing. The heat sink(s) may be embodied as a heat dissipater, a heat spreader, and/or a hermetic heat dissipater.  
      It should further be appreciated that the heat sink(s) may be any type of metallic sink with projecting portions that are metallic or made of a thermally conductive medium. Example thermally conductive materials include, but are not limited to potting compounds, gels and/or greases to extract the heat.  
      It should further be appreciated that a fan (not shown) may be included within the housing  10  to move the fluid through the battery charger  1 . The fluid can be directed by the fan so as to enable components in the charger  1  to be cooled or heated. The fan can also be coupled to electronics powered by the battery cells, the charger  1 , or both, to control cooling or heating. Further, the fan may include a motor (not shown) which may run off a battery or run off of the charger  1 .  
      Referring to  FIG. 2 , an electrical cord  100  to be plugged into an A/C outlet extends from the housing  10 . The lower housing half-shell  20  includes an indent area  60  near opening  50 . The upper housing half-shell  30  also includes an indent area  70  that corresponds with indent area  60 . In other words, when the half shells  20 ,  30  are connected to one another, indent areas  60 ,  70  are correspondingly aligned, as shown in  FIG. 1 . The indent areas  60 ,  70  are formed so that the electrical cord  100  wraps around and occupies the indent areas  60 ,  70  of the charger  1  to provide a convenient and orderly system of wrapping the cord  100  to the charger  1 .  
      The electrical cord  100  includes a plug  105  which has a groove  110  formed therein to retain or lock a portion of the wrapped cord  100  therein. This prevents unwinding of the cord  100 , or enables the wrapped cord  100  to be secured around the charger housing  10  within the indention formed by indent areas  60 ,  70 . The electrical cord  100  also may be provided with a small fastener  115  (e.g., clip) to provide further locking of the cord  100 .  
      It should be appreciated that the indent areas  60 ,  70  may be formed in other shape besides as shown in  FIG. 2  as long the areas  60 ,  70  serve the function of securing the cord  100  around the housing  100  of the charging unit  1 .  
       FIGS. 3 through 5  are side views of the charger in accordance with exemplary embodiments. As shown in  FIG. 3 , the battery charger  1  includes a battery insertion open portion  15  and a component housing portion  12 . The component housing portion  12  is larger relative to the battery insertion open portion  15  due to heat sinks and other components (not shown) that are required to cool electronics within the component housing portion  12 . The heat sinks may be positioned within the component housing  12  to transfer away heat created by the electronics, and expelled through the vent openings (not shown) located in the component housing portion  12 .  
      Referring to  FIG. 3 , the component housing portion  12  includes a top surface  25 . The top surface  25  may include a bit retention area  65  for holding tool accessories, such as, for example, drill bits or screws  71 . The bit retention area  65  may be a slot formed by injection-molding with the component housing portion  12 . The bit retention area  65  may also include a snap-fitting member formed in the slot. The snap-fitting member may be made from a metal material.  
      It should be appreciated that there may be more than one bit retention area on the top surface  25 . To further reduce breakage of the bit retention area  65 , there may be a metal insert (not shown) fitted therein.  
      Referring to  FIG. 4 , the component housing portion  12  of  FIG. 4  includes a linear blade retention area  66  for holding a blade  72 , such as a reciprocating saw blade and a jigsaw blade, for example. It should be appreciated that  FIG. 4  is similar to  FIG. 3  except for the component housing portion  12  having a linear blade retention area  66 . The linear blade retention area  66  may be a slot formed by injection-molding with the component housing portion  12 . The linear blade retention area  66  may also include a snap-fitting member formed in the slot. The snap-fitting member may be made from a metal material.  
      It should be appreciated that there may be more than one linear blade retention area on the top surface  25 . To further reduce breakage of the linear blade retention area  66 , there may be a metal insert (not shown) fitted therein.  
      Referring to  FIG. 5 , the top surface of the component housing portion  12  may further include a note pad  73  for allowing the user to write down notes, measurements and/or reminders. The note pad  73  may be a multi-sheet pad having self-adhesive tape, such as is used in office settings.  
      Thus, as illustrated in  FIGS. 3-5 , the battery charging unit  1  provides a central location for storing a variety of tool accessories and/or accessories, in addition to performing as a recharging station.  
       FIG. 6  is a schematic view of a battery charger in accordance with an exemplary embodiment. Referring to  FIG. 6 , the housing  10  of the charger  1  includes an A/C receptacle outlet  75  located on a top surface of the housing  10 . The A/C receptacle outlet  75  on the housing  10  permits other A/C devices (e.g., power tools, other battery chargers, lighting, and etc.) to be plugged into the charger  1  while the charger  1  is plugged into an electrical outlet (not shown).  
      It should be appreciated that there may be more than one A/C receptacle outlet  75  on the housing  10 , and that the A/C receptacle outlet  75  may be located at other places of the housing  10  besides the top surface.  
      It should further be appreciated that a D/C power source may be used rather than A/C.  
      Referring back to  FIG. 1 , the battery charger includes a LED display  47  on the housing  10 . The LED display  47  provides an indication that the battery is fully charged by lighting the appropriate LED light. For example, the left-most LED light indicator may indicate that the battery requires a full charge, the middle LED light indicator may indicate that the battery is partially charged, and the right-most LED light indicator may indicate that the battery is fully charged.  
      As shown in  FIG. 7 , the battery charger is similar to  FIG. 1  except with the addition of a battery pack  85  inserted in the charger. The battery pack  85  also includes an LED display  88 . The LED display  88  in the battery pack may be a three LED arrangement as similarly shown in  FIG. 1  or a single LED with different color indicators (e.g., a red light indicates a full charge is required, a yellow light indicates a partial charge is required, and a green light indicates no charge is required). Because the battery pack  85  is generally the tallest part of the charging system, the position of the LED display  88  (e.g., status of the battery) is displayed near the top of the battery pack  85 . This allows a user to see the status of the battery pack  85  from across a room and from 360 degrees around the charger  1  (e.g., adds height to the status light so that charger  1  status can be viewed over other objects which might obstruct the charger LED&#39;s from view).  
      The battery charger  1  may include an electronic circuit (not shown) within the housing  10  for controlling the LED display  88  of pack  85 . When the battery pack  85  is fully charged, the electronic circuit within the charger will provide a signal to illuminate the LED display  88  for a fully charged indication. The electronic circuit in the charger  1  may also communicate with an electronic circuit (not shown) in the battery pack  85  when the battery pack  85  is inserted in the charger  1 . The electronic circuit in the charger  1  may provide a status signal to the electronic circuit in the battery pack  85 . The battery pack electronic circuit controls and communicates the signals to the charger  1 , which is the power source of the LED display  88  on battery pack  85 .  
       FIG. 8  is a perspective view of a lower housing half-shell in accordance with an exemplary embodiment. As shown in  FIG. 8 , the lower housing half-shell  20  is an injection-molded plastic piece including a plurality of holes  90 A- 90 E, a terminal block  91  for interconnecting with a terminal block of a battery (not shown), and a printed circuit board (PCB)  95  disposed extending parallel to a housing bottom of the lower housing half-shell  20 . The plurality of holes  90 A- 90 E may correspond or align with plurality of holes (not shown) in the upper housing half-shell  30 . Once the plurality of holes in the lower and upper housing half-shells  20 ,  30  are aligned, fasteners (e.g., screws, bolts) may be inserted to connect the upper and lower housings  20 ,  30  together. It should be appreciated that the upper and lower housings  20 ,  30  may connect in a tongue-and-groove design formed around an outer periphery of housing  10  between the two housings  20 ,  30 .  
      The PCB  95  supports electrical components, such as capacitors, connectors, transformers and lights formed thereon. Components, and may be of any conventional design.  
      The lower housing half-shell  20  includes snap-on connectors  97  integrally formed and extending from the bottom surface of the lower housing half-shell  20  to engage the PCB  95 . The PCB  95  includes openings for receiving the snap-on connectors  97 . The snap-on connectors  97  are inserted into the openings in the PCB  95  to hold the PCB  95  in place within the charger housing  10 . The snap-on connectors  97  may be formed as upstanding protrusions that provide structural strength to prevent the PCB  95  from moving, particularly upwardly in the vertical direction. Further, the snap-on fasteners  97  eliminate the need of fasteners (e.g., screws, bolts), as the snap-on fasteners  97  are integrally formed with the housing  10 . This results in easier and faster assembly time of the PCB  95  therein, and lowers cost of manufacturing.  
      It should be appreciated that more than two snap-on connectors  97  may be employed, and the snap-on connectors  97  may be at other locations beside the ones shown in  FIG. 8 .  
      The exemplary embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as departure from the spirit and scope of the exemplary embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the described invention.