Patent Publication Number: US-2023150106-A1

Title: Battery pack interface

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. Pat. Application No. 17/532,630, filed Nov. 22, 2021, which is a continuation of U.S. Pat. Application No. 15/845,063, filed Dec. 18, 2017, now U.S. Pat. No. 11,179,841, which claims the benefit of U.S. Provisional Pat. Application No. 62/435,443, filed on Dec. 16, 2016, and of U.S. Provisional Pat. Application No. 62/463,427, filed Feb. 24, 2017, the entire content of each of which is hereby incorporated by reference. 
    
    
     FIELD 
     The present invention relates to battery packs and, more particularly, to an interface for a battery pack. 
     SUMMARY 
     In one independent aspect, an interface for an electrical combination may be provided. The electrical combination may include a battery pack and an electrical device, the interface being operable to connect the battery pack and the electrical device. The interface may generally include a body and a rail extending along an axis, the rail and the body defining a space therebetween, the space having a first dimension proximate a first axial location, a second dimension at a second axial location, and a third dimension at a third axial location, the first dimension, the second dimension, and the third dimension being different. 
     In some constructions, the first axial location may be proximate an insertion opening at one axial end, the first dimension being larger than the second dimension and the third dimension. The third axial location may be proximate an opposite axial end, the third dimension being smaller than the second dimension. 
     The body has a body surface extending along and substantially parallel to the axis, and the rail may have a stepped rail surface extending along the axis, the space being defined between the body surface and the rail surface. The rail surface may have a first rail surface portion proximate the first axial location, a second rail surface portion proximate the second axial location, and a third rail surface portion proximate the third axial location. The first rail surface portion, the second rail surface portion and the third rail surface portion may be substantially parallel to the axis. The rail surface may have a first angled portion connecting the first rail surface portion to the second rail surface portion and a second angled portion connecting the second rail surface portion to the third rail surface portion. 
     The rail may have a lateral dimension transverse to the axis and to the space, the rail having a first lateral dimension proximate the first axial location, a second lateral dimension proximate the second axial location, and a third lateral dimension proximate the third axial location, the first lateral dimension, the second lateral dimension, and the third lateral dimension being different. The interface may further include an electrical terminal. 
     In another independent aspect, an electrical combination may generally include an electrical device including a device housing providing a device support portion, and a circuit supported by the device housing; and a battery pack including a battery pack housing providing a pack support portion for engagement with the device support portion, a battery cell supported by the housing, power being transferrable between the battery cell and the circuit when the battery pack is connected to the device. One of the device support portion and the pack support portion may include a body and a rail extending along an axis, the rail and the body defining a space therebetween, the space having a first dimension proximate a first axial location, a second dimension at a second axial location, and a third dimension at a third axial location, the first dimension, the second dimension, and the third dimension being different, and the other of the device support portion and the pack support portion including a first portion positionable in the space at the first axial location, a second portion positionable in the space at the second location, and a third portion positionable in the space at the third location. 
     In some constructions, the first axial location may be proximate an insertion opening at one axial end, the first dimension being larger than the second dimension and the third dimension. The third axial location may be proximate an opposite axial end, the third dimension being smaller than the second dimension. 
     The body has a body surface extending along and substantially parallel to the axis, and the rail may have a stepped rail surface extending along the axis, the space being defined between the body surface and the rail surface. The rail surface may have a first rail surface portion proximate the first axial location, a second rail surface portion proximate the second axial location, and a third rail surface portion proximate the third axial location. The first rail surface portion, the second rail surface portion and the third rail surface portion may be substantially parallel to the axis. The rail surface may have a first angled portion connecting the first rail surface portion to the second rail surface portion and a second angled portion connecting the second rail surface portion to the third rail surface portion. 
     The rail may have a lateral dimension transverse to the axis and to the space, the rail having a first lateral dimension proximate the first axial location, a second lateral dimension proximate the second axial location, and a third lateral dimension proximate the third axial location, the first lateral dimension, the second lateral dimension, and the third lateral dimension being different. The electrical device may further include a device terminal, and the battery pack may further include a pack terminal electrically connectable to facilitate transfer of power between the electrical device and the battery pack. 
     In some constructions, the pack support portion may include the body and the rail defining the space therebetween, and the device support portion may include an axially-extending device rail providing the first portion, the second portion, and the third portion. The device support portion may include a device body, the device rail and the device body defining a second space therebetween, the second space having a fourth dimension proximate a first portion, a fifth dimension proximate the second portion, and a sixth dimension proximate the third portion, the fourth dimension, the fifth dimension and the sixth dimension being different. 
     The device rail may have a lateral dimension transverse to the axis and to the second space, the device rail having a fourth lateral dimension proximate the first portion, a fifth lateral dimension proximate the second portion, and a sixth lateral dimension proximate the third portion, the fourth lateral dimension, the fifth lateral dimension, and the sixth lateral dimension being different. 
     In yet another independent aspect, a latch mechanism for an electrical combination may be provided. The electrical combination may include a battery pack and an electrical device, the latch mechanism being operable to connect the battery pack and the electrical device. The latch assembly may generally include a latching member movable between a latched position, in which the latching member is engageable between the battery pack and the electrical device to inhibit relative movement, and an unlatched position, in which relative movement is permitted; and a switch operable with the latching member, the switch inhibiting power transfer between the battery pack and the electrical device when the latching member is between the latched position and the unlatched position. 
     The latching member may be engageable in a latching recess to inhibit relative movement between the battery pack and the electrical device, and the switch may be operable to inhibit power transfer before the latching member disengages the latching recess. In the latched position, the switch may be operable to facilitate power transfer. 
     The latching mechanism may further include an actuator engageable by a user to move the latching member between the latched position and the unlatched position. The actuator may be a primary actuator, and the latch mechanism may further include a secondary actuator operatively coupled to the primary actuator and movable between a first position, in which the secondary actuator inhibits operation of the primary actuator, and a second position, in which the secondary actuator allows operation of the primary actuator. The latching member may be formed of a first material, and the actuator may be formed of a different second material, the first material being harder than the second material. The latching member may include a protrusion engageable with and operating the switch to inhibit power transfer as the latching member moves toward the unlatching position. 
     In a further independent aspect, an electrical combination may generally include an electrical device including a device housing providing a device support portion, and a circuit supported by the device housing; a battery pack including a battery pack housing providing a pack support portion for engagement with the device support portion, a battery cell supported by the housing, power being transferrable between the battery cell and the circuit when the battery pack is connected to the device; and a latch mechanism including a latching member movable between a latched position, in which the latching member is engageable between the battery pack and the electrical device to inhibit relative movement, and an unlatched position, in which relative movement is permitted, and a switch operable with the latching member, the switch inhibiting power transfer between the battery pack and the electrical device when the latching member is between the latched position and the unlatched position. 
     The latching member may be engageable in a latching recess to inhibit relative movement between the battery pack and the electrical device, and the switch may be operable to inhibit power transfer before the latching member disengages the latching recess. The latching member may be supported on the device support portion, and the latching recess may be defined on the pack support portion. In the latched position, the switch may be operable to facilitate power transfer. 
     The latching mechanism may further include an actuator engageable by a user to move the latching member between the latched position and the unlatched position. The actuator may be a primary actuator, and the latch mechanism may further include a secondary actuator operatively coupled to the primary actuator and movable between a first position, in which the secondary actuator inhibits operation of the primary actuator, and a second position, in which the secondary actuator allows operation of the primary actuator. The latching member may be formed of a first material, and the actuator may be formed of a different second material, the first material being harder than the second material. The latching member may include a protrusion engageable with and operating the switch to inhibit power transfer as the latching member moves toward the unlatching position. 
     The electrical device may further include a device terminal, the battery pack may further include a pack terminal electrically connectable to facilitate transfer of power between the electrical device and the battery pack, and, when the battery pack is connected to the electrical device, the switch may inhibit power transfer between the battery pack and the electrical device before the device terminal and the pack terminal are electrically disconnected. 
     In another independent aspect, an ejector for an electrical combination may be provided. The electrical combination may include a battery pack and an electrical device. The ejector may generally include an ejection member engageable between the battery pack and the electrical device; a biasing member operable to bias the ejection member toward an ejecting position, in which a force is applied to disengage the battery pack and the electrical device; and a switch operable with the ejection member, the switch deactivating at least a portion of the device as the ejection member moves toward the ejecting position. The ejection member may be movable to a retracted position, opposite the ejecting position, the switch activating at least a portion of the device as the ejection member moves toward the retracted position. 
     In yet another independent aspect, an electrical combination may generally include an electrical device including a device housing providing a device support portion, and a circuit supported by the device housing; a battery pack including a battery pack housing providing a pack support portion for engagement with the device support portion, a battery cell supported by the housing, power being transferrable between the battery cell and the circuit when the battery pack is connected to the device; and an ejector. The ejector may include an ejection member engageable between the battery pack and the electrical device, a biasing member operable to bias the ejection member toward an ejecting position, in which a force is applied to disengage the battery pack and the electrical device, and a switch operable with the ejection member, the switch deactivating at least a portion of the device as the ejection member moves toward the ejecting position. 
     The ejection member may be movable to a retracted position, opposite the ejecting position, the switch activating at least a portion of the device as the ejection member moves toward the retracted position. The electrical device may further include a device terminal, the battery pack may further include a pack terminal electrically connectable to facilitate transfer of power between the electrical device and the battery pack, and, when the battery pack is connected to the electrical device, the switch inhibits power transfer between the battery pack and the electrical device before the device terminal and the pack terminal are electrically disconnected. 
     The electrical device may include a first power tool including a first tool housing providing a first tool support portion, and a first motor supported by the first tool housing, the pack support portion being engageable with the first tool support portion, the battery cell being operable to power the first motor when the battery pack is connected to the first power tool, the biasing member having a first stiffness selected based on a characteristic of the first power tool. The electrical combination may further include a second power tool including a second tool housing providing a second tool support portion, and a second motor supported by the second tool housing, the pack support portion being engageable with the second tool support portion, the battery cell being operable to power the second motor when the battery pack is connected to the second power tool; and a second ejector including a second ejection member engageable between the battery pack and the second power tool, a second biasing member operable to bias the second ejection member toward an ejecting position, in which a force is applied to disengage the battery pack and the power tool, the second biasing member having a second stiffness selected based on a characteristic of the second power tool, the second stiffness being different than the first stiffness. 
     In a further independent aspect, a dual-action latch mechanism for an electrical combination may be provided. The electrical combination may include a battery pack and an electrical device, the latch mechanism being operable to connect the battery pack and the electrical device. The latch mechanism may generally include a primary actuator operatively coupled to a latching member movable between a latched position, in which the latching member is engageable between the battery pack and the electrical device to inhibit relative movement, and an unlatched position, in which relative movement is permitted; and a secondary actuator operatively coupled to the primary actuator and movable between a first position, in which the secondary actuator inhibits operation of the primary actuator, and a second position, in which the secondary actuator allows operation of the primary actuator. 
     The latch mechanism may further include the latching member; and a switch operable with the latching member, the switch inhibiting power transfer between the battery pack and the electrical device when the latching member is between the latched position and the unlatched position. The latching member may be engageable in a latching recess to inhibit relative movement between the battery pack and the electrical device, and the switch may be operable to inhibit power transfer before the latching member disengages the latching recess. In the latched position, the switch may be operable to facilitate power transfer. 
     The latching member may be formed of a first material, and the actuator may be formed of a different second material, the first material being harder than the second material. The latching member may include a protrusion engageable with and operating the switch to inhibit power transfer as the latching member moves toward the unlatching position. 
     In another independent aspect, an electrical combination may generally include an electrical device including a device housing providing a device support portion, and a circuit supported by the device housing; a battery pack including a battery pack housing providing a pack support portion for engagement with the device support portion, a battery cell supported by the housing, power being transferrable between the battery cell and the circuit when the battery pack is connected to the device; and a dual-action latch mechanism including a primary actuator operatively coupled to a latching member movable between a latched position, in which the latching member is engageable between the battery pack and the electrical device to inhibit relative movement, and an unlatched position, in which relative movement is permitted, and a secondary actuator operatively coupled to the primary actuator and movable between a first position, in which the secondary actuator inhibits operation of the primary actuator, and a second position, in which the secondary actuator allows operation of the primary actuator. 
     The latch mechanism may further include the latching member, and a switch operable with the latching member, the switch inhibiting power transfer between the battery pack and the electrical device when the latching member is between the latched position and the unlatched position. The latching member may be engageable in a latching recess to inhibit relative movement between the battery pack and the electrical device, and the switch may be operable to inhibit power transfer before the latching member disengages the latching recess. In the latched position, the switch may be operable to facilitate power transfer. 
     The latching member may be formed of a first material, and the actuator may be formed of a different second material, the first material being harder than the second material. The latching member may include a protrusion engageable with and operating the switch to inhibit power transfer as the latching member moves toward the unlatching position. 
     In yet another independent aspect, a battery pack may generally include a housing assembly providing a terminal block and a pack support portion engageable along an axis with a device support portion of an electrical device, the housing assembly defining a cavity, the housing assembly having a bottom wall opposite the pack support portion, a first end wall portion opposite the terminal block, connected to the pack support portion, and extending in a plane substantially perpendicular to the axis, and a second end wall connected between the bottom wall and the first end wall portion, the second end wall portion being oriented at an angle between 90 degrees and 180 degrees relative to the first end wall portion; a plurality of battery cells supported in the cavity; and a pack terminal supported by the terminal block and engageable with a device terminal of the electrical device. The second end wall portion may be oriented at an angle of between about 110 degrees and about 160 degrees. The second end wall portion may be oriented at an angle of about 135 degrees. 
     In a further independent aspect, a battery pack may generally include a housing including a support portion connectable to and supportable by an electrical device, the support portion defining a channel operable to receive a projection on the electrical device, the support portion including a plastic material molded to define the channel, and a metal material molded in the plastic material, the metal material defining a C-shaped portion around the channel; a plurality of battery cells supported by the housing; and a battery terminal electrically connected to the plurality of battery cells and connectable to a terminal of the electrical device. 
     In another independent aspect, a battery pack may generally include a housing including a support portion connectable to and supportable by an electrical device, the housing also including a bottom wall opposite the support portion; opposite side walls connected between the bottom wall and the support portion and opposite end walls connected between the bottom wall and the support portion and between the side walls, adjacent walls meeting at an edge; elastomeric material on at least one edge, the elastomeric material being thickest proximate the edge and thinning in a direction away from the edge; a plurality of battery cells supported by the housing; and a battery terminal electrically connected to the plurality of battery cells and connectable to a terminal of the electrical device. 
     In a yet another independent aspect, a shock absorption assembly may be provided for an interface between a battery pack and an electrical device. The assembly may include a housing assembly including a first housing portion having an outer surface and providing a support portion connectable to and operable to support the battery pack, a second housing portion at least partially around the first housing portion and having an inner surface in facing relationship to the outer surface; a post supported by one of the first housing portion and the second housing portion supporting a post, the other of the first housing portion and the second housing portion defining a recess aligned with the post; and a shock absorption member supported on the post and received in the recess. 
     Other independent features and independent aspects of the invention may become apparent by consideration of the following detailed description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view of a battery pack coupled to a battery-receiving portion of an electrical device according to a first embodiment. 
         FIG.  2    is a perspective view of the battery-receiving portion shown in  FIG.  1   . 
         FIG.  3    is a bottom view of the battery-receiving portion as shown in  FIG.  2   . 
         FIG.  4    is a cross-sectional side view of the battery-receiving portion as shown in  FIG.  2   . 
         FIG.  5    is an enlarged perspective view of a spring ejector of the battery-receiving portion shown in  FIG.  2   . 
         FIG.  6    is a partial cross-sectional perspective view of the spring ejector shown in  FIG.  5   . 
         FIG.  7    is a perspective view of the battery pack shown in  FIG.  1   . 
         FIG.  8    is an enlarged perspective view of a portion of the battery pack shown in  FIG.  7   . 
         FIG.  9 A  is a second enlarged perspective view of a portion of the battery pack shown in  FIG.  7   . 
         FIG.  9 B  is a third enlarged perspective view of a portion of the battery pack shown in  FIG.  7   . 
         FIG.  10    is a top view of the battery pack shown in  FIG.  7   . 
         FIG.  11    is a cross-sectional side view of the battery pack coupled to the battery-receiving portion as shown in  FIG.  1   . 
         FIG.  12 A  is a cross-sectional side view of a latching mechanism of the battery-receiving portion shown in  FIG.  11   , illustrated in a latched position. 
         FIG.  12 B  is a cross-sectional side view of the latching mechanism shown in  FIG.  12 A , illustrated in an intermediate position. 
         FIG.  12 C  is a cross-sectional side view of the latching mechanism shown in  FIG.  12 A , illustrated in an unlatched position. 
         FIG.  13 A  is a cross-sectional side view of the spring ejector shown in  FIG.  5   . 
         FIG.  13 B  is a cross-sectional side view of the spring ejector shown in  FIG.  13 A , illustrating when the battery pack is coupled to the battery-receiving portion. 
         FIG.  14    is a perspective view of a battery pack coupled to a battery-receiving portion of an electrical device according to a second embodiment. 
         FIG.  15    is a perspective view of the battery-receiving portion shown in  FIG.  14   . 
         FIG.  16    is a bottom view of the battery-receiving portion shown in  FIG.  15   . 
         FIG.  17    is a cross-sectional side view of the battery-receiving portion shown in  FIG.  15   . 
         FIG.  18    is a perspective view of the battery pack shown in  FIG.  14   . 
         FIG.  19    is a top view of the battery pack shown in  FIG.  18   . 
         FIG.  20 A  is a cross-sectional side view of a latching mechanism of the battery-receiving portion shown in  FIG.  17   , illustrated in a latched position. 
         FIG.  20 B  is a side view of a cross section of the latching mechanism as shown in  FIG.  20 A , illustrated in an intermediate position. 
         FIG.  20 C  is a side view of a cross section of the latching mechanism as shown in  FIG.  20 A , illustrated in an unlatched position. 
         FIG.  21    is a perspective view of a battery-receiving portion of an electrical device according to a third embodiment. 
         FIG.  22    is a bottom view of the battery-receiving portion shown in  FIG.  21   . 
         FIG.  23    is a cross-sectional side view of the battery-receiving portion shown in  FIG.  21   . 
         FIG.  24    is a perspective view of a battery pack for use with the battery-receiving portion of  FIG.  21   . 
         FIG.  25    is an enlarged perspective view of a portion of the battery pack shown in  FIG.  24   . 
         FIG.  26    is a top view of the battery pack shown in  FIG.  24   . 
         FIG.  27    is a perspective view of a portion of battery pack coupled to the battery-receiving portion of  FIG.  21   . 
         FIG.  28    is a perspective view of the portion of battery pack shown in  FIG.  27   , illustrated as partially engaged with the battery-receiving portion of  FIG.  21   . 
         FIG.  29    is a cross-sectional side view of an alternative construction of a latching mechanism of a battery-receiving portion. 
         FIG.  30    is a perspective view of a battery-receiving portion of an electrical device according to a fourth embodiment. 
         FIG.  31    is a top view of the battery-receiving portion shown in  FIG.  30   . 
         FIG.  32    is a cross-sectional side view of the battery-receiving portion shown in  FIG.  30   . 
         FIG.  33    is a front view of the battery receiving portion shown in  FIG.  30   . 
         FIG.  34    is a perspective view of a battery-receiving portion of an electrical device according to a fifth embodiment. 
         FIG.  35    is a top view of the battery-receiving portion shown in  FIG.  34   . 
         FIG.  36    is a cross-sectional side view of the battery-receiving portion shown in  FIG.  34   . 
         FIG.  37    is a front view of the battery receiving portion shown in  FIG.  34   . 
         FIG.  38    is a perspective view of a battery pack for use with the battery-receiving portion. 
         FIG.  39    is an enlarged perspective view of a portion of the battery pack shown in  FIG.  38   . 
         FIG.  40    is a top view of the battery pack shown in  FIG.  38   . 
         FIG.  41    is a perspective view of an electrical device, such as a charger, including a battery-receiving portion. 
         FIG.  42    is a top view of the device of  FIG.  41   . 
         FIG.  43    is a partial cross-sectional side view of the device of  FIG.  41   . 
         FIGS.  44 A- 44 I  are views of an alternative construction of a battery pack. 
         FIG.  45    is a side view of a battery pack and a portion of an electrical device illustrating the battery pack impacting a surface. 
         FIGS.  46 A- 46 B  are views of a battery pack illustrating overmold material. 
         FIGS.  47 A- 47 B  are views of a support portion of the battery pack. 
         FIGS.  48 A- 48 F  are views of a portion of a battery interface illustrating a shock absorption arrangement. 
         FIGS.  49 A- 49 H  are views of another alternative construction of a battery pack. 
     
    
    
     DETAILED DESCRIPTION 
     Before any independent embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other independent embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
     Use of “including” and “comprising” and variations thereof as used herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Use of “consisting of” and variations thereof as used herein is meant to encompass only the items listed thereafter and equivalents thereof. Unless specified or limited otherwise, the terms “mounted,” “connected,” “supported,” and “coupled” and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. 
     Also, the functionality described herein as being performed by one component may be performed by multiple components in a distributed manner. Likewise, functionality performed by multiple components may be consolidated and performed by a single component. Similarly, a component described as performing particular functionality may also perform additional functionality not described herein. For example, a device or structure that is “configured” in a certain way is configured in at least that way but may also be configured in ways that are not listed. 
     Furthermore, some embodiments described herein may include one or more electronic processors configured to perform the described functionality by executing instructions stored in non-transitory, computer-readable medium. Similarly, embodiments described herein may be implemented as non-transitory, computer-readable medium storing instructions executable by one or more electronic processors to perform the described functionality. As used in the present application, “non-transitory computer-readable medium” comprises all computer-readable media but does not consist of a transitory, propagating signal. Accordingly, non-transitory computer-readable medium may include, for example, a hard disk, a CD-ROM, an optical storage device, a magnetic storage device, a ROM (Read Only Memory), a RAM (Random Access Memory), register memory, a processor cache, or any combination thereof. 
     Many of the modules and logical structures described are capable of being implemented in software executed by a microprocessor or a similar device or of being implemented in hardware using a variety of components including, for example, application specific integrated circuits (“ASICs”). Terms like “controller” and “module” may include or refer to both hardware and/or software. Capitalized terms conform to common practices and help correlate the description with the coding examples, equations, and/or drawings. However, no specific meaning is implied or should be inferred simply due to the use of capitalization. Thus, the claims should not be limited to the specific examples or terminology or to any specific hardware or software implementation or combination of software or hardware. 
       FIG.  1   -13B illustrate a battery-receiving portion  50  of an electrical device (e.g., a power tool, an outdoor tool, a non-motorized device (e.g., a light, an audio device, etc.), a battery charger, etc.) configured to receive a battery pack  54  (e.g., a rechargeable lithium-ion battery pack). As will be described in greater detail below, an interface for the battery pack  54  (e.g., the illustrated battery-receiving portion  50  (see  FIGS.  2 - 4   )) includes stepped grooves  58  and a latching mechanism  66  to facilitate coupling of the battery pack  54  to the battery-receiving portion  50 . In other embodiments (not shown), the grooves  58  may be substantially linear. 
     With reference to  FIGS.  1 - 6   , the battery-receiving portion  50  includes a cavity  70  defined by a lower surface  74 , a pair of sidewalls  78 , and an end wall  82  and having an open end  86  opposite the end wall  82 . In addition, an upper end wall  90  extends above the end wall  82  proximate the cavity  70 . Device contacts  94  are supported on the end wall  82  and are configured to mechanically and electrically interface with the battery pack  54  to transfer electrical power therebetween. 
     In the illustrated embodiment, at least a portion of the latching mechanism  66  protrudes from the lower surface  74  near the open end  86 . The latching mechanism  66  is configured to engage the battery pack  54  to maintain engagement between the battery pack  54  and the battery-receiving portion  50 . However, in other embodiments (not shown), the latching mechanism  66  may be disposed at various locations (e.g., on a sidewall  78 , the end wall  82 , the upper end wall  90 , etc.) such that the latching mechanism  66  engages corresponding structure on the battery pack  54  to maintain engagement between the battery pack  54  and the battery-receiving portion  50 . 
     With specific reference to  FIGS.  2 - 4   , the battery-receiving portion  50  includes stepped grooves  58  extending between the open end  86  and the end wall  82  (e.g., as illustrated, from the open end  86  to the end wall  82 ). The stepped grooves  58  are defined by rails  98  disposed on the sidewalls  78 . The rails  98  protrude from the sidewalls  78  to define an upper extent of the grooves  58  that face the lower surface  74 . 
     As shown in  FIG.  4   , the illustrated rails  98  include a number of (e.g., three) generally parallel horizontal portions  102  defining distinct vertical clearances C 1 , C 2 , C 3  ... Cn of the grooves  58  measured between each horizontal portion  102  and the lower surface  74 . Each horizontal portion  102  is connected by an angled portion  106  extending obliquely toward the lower surface  74  (e.g., when moving from left to right in  FIG.  4   ) such that each horizontal portion  102  defines a successively smaller clearance, thereby forming the “stepped” configuration of the grooves  58 . In the illustrated embodiment, the vertical clearance C 1 , C 2 , C 3  of each of the horizontal portions  102  changes by a constant amount. 
     In other embodiments (not shown), the rails  98  may include two horizontal portions  102  or more than three horizontal portions  102 . In addition, these portions  102  may be disposed at an angle relative to the lower surface  74 . In other embodiments, the vertical clearances C 1 , C 2 , C 3  may vary by different amounts (e.g., the difference in clearance may be greater or less than the difference in adjacent clearances). 
     A horizontal clearance is measured from the sidewall  78  to a periphery of the rails  98 . In the illustrated embodiment (see  FIG.  3   ), a stepped configuration is provided laterally between the opposite rails  98 . The rails  98  include a number of (e.g., three) generally parallel axially-extending portions  107  defining distinct lateral clearances L 1 , L 2 , L 3 ...Ln therebetween. Each portion is connected to an angled portion  108  extending obliquely toward the opposite rail  98  (e.g., when moving from right to left in  FIG.  3   ) such that the opposite portions  107  define a successively smaller lateral clearance, thereby forming the “stepped” configuration between the rails  98 . In the illustrated embodiment, the lateral clearance L 1 , L 2 , L 3  between each portion  107  changes by a constant amount. 
     In other embodiments (not shown), the rails  98  may include two portions  107  or more than three portions  107 . In addition, these portions  107  may be disposed at an angle relative to the rail  98 . In other embodiments, the lateral clearances L 1 , L 2 , L 3  may vary by different amounts (e.g., the difference in clearance may be greater or less than the difference in adjacent clearances). 
     As shown in  FIGS.  2 ,  4 , and  11   -12C, the latching mechanism  66  includes a pivotable actuator or handle  110  operatively engaging a latch member  114 . The latch member  114  is slidably disposed in a bore  118  defined in the lower surface  74  and is biased by one or more biasing members (e.g., a spring  122 , such as a coil spring, a torsion spring, etc.) to protrude through the lower surface  74  and into the cavity  70 . The latch member  114  has an inclined surface  126  (e.g., angled about 30 degrees to about 60 degrees relative to the lower surface  74 ) facing toward the open end  86  and a generally vertically-extending surface  130  (e.g., about 0 degrees to about 10 degrees relative to a vertical axis) facing toward the end wall  82 . 
     The latch member  114  is coupled to the spring  122 . In some embodiments (not shown), two or more springs  122  may be coupled to the latch member  114 . In such multi-spring arrangements, each spring  122  may be smaller/shorter, leading to a shorter overall height of the latch member  114  and the spring  122  without a reduction in biasing force. 
     The handle  110  is engaged with the latch member  114  via a cam surface  131  such that actuation (e.g., clockwise pivoting/rotation of the handle  110  with respect to the position shown in  FIG.  4   ) of the handle  110  causes the latch member  114  to translate downward against the bias of the spring  122  to withdraw the latch member  114  from the cavity  70 . 
     The latching mechanism  66  may be constructed for reduced wear. For example, the latch member  114  (and/or the latching recess (e.g., the slot  182 ) with which the latch member  114  is engageable) may be formed of or have one or more engagement surfaces including wear-resistant material. In the illustrated construction, the latch member  114  includes a polycarbonate (PC)-based material, such as, for example KINGFA® JH830, manufactured by Kingfa Science &amp; Technology Co., Guangzhou, PRC. The material of the latch member  114  may, for example, increase hardness, impact resistance, wear resistance, etc., compared to Acrylonitrile butadiene styrene (ABS) or softer plastics. 
     The illustrated latching mechanism  66  also includes a switch  134  (e.g., a micro-switch  134 ) facilitating electrical coupling/decoupling of the battery pack  54  during actuation of the handle  110  to withdraw the latch member  114  from the cavity  70 . In other embodiments, however, the switch  134  may be omitted. As will be described in greater detail with respect to  FIGS.  12 A- 12 C , the switch  134  may act to electrically decouple the battery pack  54  from the battery-receiving portion  50  and the device prior to removal of the battery pack  54  from the battery-receiving portion  50 . 
     With reference to  FIGS.  4 - 6  and  13 A- 13 B , an ejector  138  is supported on the end wall  90 . The ejector  138  includes an ejection member  142  biased by a biasing member (e.g., one or more springs (not shown)) to protrude through the end wall  90  (as shown in  FIGS.  4 - 6  and  13 A ). When the battery pack  54  is attached to the battery-receiving portion  50  (see  FIG.  13 B ), the ejection member  142  is pushed into the end wall  90  to compress the biasing member. From this position, the spring ejector  138  is configured to exert a force F on the battery pack  54  to push the battery pack  54  out of engagement with the battery-receiving portion  50  (e.g., upon release of the latching mechanism  66 ). 
     The stiffness of the ejector spring(s) may be tailored to the electrical device to which the battery pack  54  is connected. The stiffness may be based on a characteristic of the electrical device, such as, for example, a weight, mass, size, etc. of the electrical device, a speed of a motor (if provided), vibration generated by operation of the electrical device, etc. For example, for a power tool, such as a core drill, the stiffness of the spring(s) may be greater than that for another electrical device having a lower weight/mass, no motor, generating less vibration, etc. In contrast, for an electrical device, such as a charger, the stiffness may be relatively less to provide a decreased biasing force. 
     In another example, the biasing force of the ejector spring(s) may be different based on the electrical device. A stationary device, such as a table saw, a battery charger, etc., may require the ejector spring(s) to have increased biasing force to assist with ejection of the battery pack  54  from the electrical device, compared to a movable device, such as a hand-held power tool, which may be adjusted (e.g., moved to a position) to assist with removal of the battery pack  54 . 
     In the some embodiments (as shown in  FIGS.  4 ,  6  and  13 A- 13 B ), a switch  146  (e.g., an AC switch  146 ) is incorporated into the ejector  138 . The switch  146  is configured to activate/deactivate an electrical device (e.g., a battery charger) based on a position of the battery pack  54  relative to the battery-receiving portion  50 . In one example, pushing the ejection member  142  into the end wall  90  causes the ejection member  142  to engage and activate the switch  146 . The switch  146  may be activated to permit power to be transferred to a portion of the device (e.g., a master board of a charger, etc.) when the battery pack  54  is initially inserted but prior to activation of the device contacts  94  (e.g., for charging operations). 
       FIGS.  7 - 10    illustrate a battery pack  54  for use with the battery-receiving portion  50 , described above. The battery pack  54  includes a housing  150  defining an internal cavity in which one or more battery cells (not shown) are supported. Each battery cell may have a nominal voltage between about 3 V and about 5 V and may have a nominal capacity between about 2 Ah and about 6 Ah (in some cases, between about 3 Ah and about 5 Ah). The battery cells may be any rechargeable battery cell chemistry type, such as, for example, lithium (Li), lithium-ion (Li-ion), other lithium-based chemistry, nickel-cadmium (NiCd), nickel-metal hydride (NiMH), etc. 
     The battery cells may be connected in series, parallel, or combination series-parallel to provide the desired electrical characteristics (e.g., nominal voltage, current output, current capacity, power capacity, etc.) of the battery pack  54 . The battery cells are coupled to battery contacts  154  supported on or within the housing  150  and configured to electrically and mechanically engage the device contacts  94  to facilitate the transfer of electrical power between the device and the battery pack  54 . As will be described in greater detail below, the battery pack  54  includes mechanical features configured to engage corresponding features on the battery-receiving portion  50  to couple and maintain engagement of the battery-receiving portion  50  and the battery pack  54 . 
     The housing  150  includes a protrusion  148  supporting, at a front end  158 , the battery contacts  154 . On each lateral side  162 , a rail  166  extends laterally outwardly and to define a groove  170 . Proximate a rear end  174 , a top surface  178  defines a slot  182  sized and shaped to cooperate with the latch member  114 . 
     In the illustrated embodiment, the rails  166  include a number of (e.g., three) parallel horizontal portions  186  defining distinct vertical clearances C 4 , C 5 , C 6 ... Cn of the grooves  170  measured between each horizontal portion  186  and the body of the housing  150 . Each portion  186  is connected by an angled portion  190  extending obliquely away from the housing  150  when moving from the rear end  174  toward the front end  158  so each horizontal portion  186  defines a successively smaller clearance. As illustrated, the rails  166 /grooves  170  of the battery pack  54  form a mated engagement between the rails  98 /grooves  58  of the battery-receiving portion  50 . 
     A horizontal clearance is measured from the lateral side  162  to a periphery of each rail  166 . In the illustrated embodiment (see  FIG.  10   ), a stepped configuration is provided laterally between the opposite rails  166 . The rails  166  include a number of (e.g., three) generally parallel axially-extending portions  191  defining distinct lateral dimensions L 4 , L 5 , L 6 ...Ln therebetween. Each portion is connected to an angled portion  192  extending obliquely toward the opposite rail  166  (e.g., when moving from right to left in  FIG.  10   ) such that the opposite portions  191  define a successively smaller lateral dimension, thereby forming the “stepped” configuration between the rails  166 . In the illustrated embodiment, the lateral dimension L 4 , L 5 , L 6  between each portion  191  changes by a constant amount. 
     It should be understood that, if the size and shape of the battery-receiving portion  50  is modified, corresponding variations in the size and shape of the battery pack  54  may be made. For example, the geometric configuration of the rails  98 ,  166  will be consistently varied in order to maintain the mating engagement between the battery pack  54  and the battery-receiving portion  50 . It should be understood that, in other constructions (not shown), the orientation of the rails  98 ,  166  may be reversed with the rails  98  being directed outwardly and the rails  166  being directed inwardly. 
     With reference to  FIGS.  1 ,  11 ,  12 A-C, and  13 B , the battery pack  54  is coupled to the battery-receiving portion  50  by aligning the rails  166  of the battery pack  54  with the grooves  58  of the battery-receiving portion  50 , and subsequently sliding the battery pack  54  along a battery insertion axis  194  until the device contacts  94  engage the battery contacts  154 . 
     In order to allow the sliding of the battery pack  54  onto the battery-receiving portion  50 , the latch member  114  retracts into the bore  118  in the lower surface  74 . To do so, a user may pivot the handle  110  to retract the latch member  114  while sliding the battery pack  54 , or the user may simply slide the battery pack  54  relative to the battery-receiving portion  50  such that the front end  158  of the protrusion  148  engages the inclined surface  126 . The angle of the inclined surface  126  causes the force exerted by the front end  158  to act vertically against the bias of the spring  122  such that the latch member  114  is “automatically” retracted into the bore  118  when the battery pack  54  slides through the cavity  70 . 
     The size and shape of the rails  166  relative to the grooves  58  (and of the rails  98  relative to the grooves  170 ) act to facilitate and guide insertion of the battery pack  54  onto the battery-receiving portion  50 . The relative clearances defined between the rails  166  and the grooves  58  decrease as the battery pack  54  is inserted further onto the battery-receiving portion  50 . In the illustrated embodiment, engagement between the rails  166  and the grooves  58  (and between the rails  98  and the grooves  170 ) is closest proximate the front end  158  and the end wall  82  and proximate the rear end  174  and the open end  86 . This construction may facilitate a tighter, more secure engagement between the battery pack  54  and the battery-receiving portion  50  as the battery pack  54  approaches and reaches full insertion. 
     In the illustrated embodiment, increased clearance is provided between the rails  166  relative to the grooves  58  (and of the rails  98  relative to the grooves  170 ) in the region between the front end  158 /the end wall  82  and the rear end  174 /the open end  86 . This arrangement may facilitate smooth and easy insertion of the battery pack  54  due to, for example, reduced engagement, interference, etc. 
     When the battery pack  54  is fully inserted ( FIGS.  1 ,  11  and  12 A ), the latch member  114  protrudes from the lower surface  74  to engage the slot  182  on the protrusion  148  thereby latching the battery pack  54  to the battery-receiving portion  50  (e.g., in a latched or locked position). The spring  122  biases the latching member  114  to engage the slot  182 , and the vertical surface  130  of the latching member  114  engages a corresponding surface on the interior of the slot  182 . Removal (and ejection) of the battery pack  54  along the insertion axis  194  is inhibited by the latch member  114 . This engagement of the latching member  114  may also ensure and maintain close mechanical and electrical connection of the pack contacts  154  and the device contacts  94 . 
       FIGS.  12 A- 12 C  illustrate operation of the pivot-actuated latching mechanism  66 . As the latch member  114  is moved from the latched position ( FIG.  12 A ) to an intermediate position ( FIG.  12 B ), the switch  134  is activated to inhibit the transfer of electrical power between the battery pack  54  and the device before the battery pack  54  is released by the latching member  114  and removable from the battery-receiving portion  50  and before the contacts  154 ,  94  disengage. Activation of the switch  134  to stop power transfer between the battery pack  54  and the device may, for example, prevent arcing between the contacts  154 ,  94  as the battery pack  54  is removed. 
     Further movement of the latching member  114  to an unlatched position ( FIG.  12 C ) removes the latching member  114  from the slot  182 , and the battery pack  54  is permitted to move along the battery insertion axis  194  off of the battery-receiving portion  50 . The switch  134  is maintained in the on position to continue inhibiting the transfer of power between the battery pack  54  and the device. 
     As illustrated in  FIGS.  12 A- 12 C , the latch member  114  includes a protrusion  198  engaging an actuator  196  of the switch  134 . In the illustrated construction, the intermediate position ( FIG.  12 B ) in which the switch  134  is actuated is approximately halfway between the latched position ( FIG.  12 A ) and the unlatched position ( FIG.  12 C ) of the latch member. In other embodiments (not shown), actuation of the switch  134  may occur at any point between the latched and unlatched positions of the latch member  114 . 
       FIGS.  13 A- 13 B  illustrate operation of the ejector  138 . When the battery pack  54  is fully inserted onto the battery-receiving portion  50  (see  FIG.  13 A ), the ejection member  142  is pushed into the end wall  90  and the biasing member is compressed (e.g., the compressed condition of the ejector  138 ). In the compressed position, the ejection member  142  actuates the switch  146  to activate the electrical device (e.g., to permit power to be transferred to a portion of the device (e.g., a master board of a charger, etc.)). 
     When the latching member  114  is moved to the unlatched position (see  FIG.  12 C ), the biased ejection member  142  exerts a force F along the direction of the battery insertion axis  194  to force the battery pack  54  toward disengagement from the battery-receiving portion  50  (e.g., the eject position (see  FIG.  13 B )). In one example, the ejection member  142  forces the battery pack  54  to a position in which the battery contacts  154  and the device contacts  94  become mechanically and electrically disengaged. As mentioned above, prior to this movement, the switch  134  has been activated to inhibit the transfer of electrical power between the battery pack  54  and the device. Displacement of the ejection member  142  to protrude through the end wall  90  disengages the switch  146  to deactivate a portion of the device (e.g., to inhibit power transfer to a portion of the device (such as the master board)), to disconnect the device contacts  94 , or both. 
       FIG.  14   -20C illustrate an alternative construction of a battery-receiving portion  250  of an electrical device configured to receive a corresponding battery pack  254 . The battery-receiving portion  250  and the corresponding battery pack  254  are similar to the battery-receiving portion  50  and the battery pack  54  shown in  FIG.  1   -13B, and common elements have the same reference number plus “200”. 
     The following description will focus on aspects of the battery-receiving portion  250  and battery pack  254  different than the battery-receiving portion  50  and the battery pack  54 . It should be noted, however, that features of the battery-receiving portion  250  or the battery pack  254  may be incorporated or substituted into the battery-receiving portion  50  or the battery pack  54 , or vice versa. 
     The battery-receiving portion  250  includes a first cavity  252  and a second cavity  256 . The illustrated cavities  252 ,  256  are aligned but separated by a solid portion  260 . The first cavity  252  is defined by a first lower surface  264 , a pair of sidewalls  268 , a first end wall  272 , and an open end  286  opposite the first end wall  272 . The second cavity  256  is similarly defined by a second lower surface  276 , a pair of sidewalls  280 , a second end wall  284 , and a third end wall  288  opposite the second end wall  284 . 
     In the illustrated embodiment, at least a portion of a latching mechanism  266  protrudes from the first lower surface  264  and is configured to engage the battery pack  254  to maintain a connection between the battery pack  254  and the battery-receiving portion  250 . However, in other embodiments (not shown), the latching mechanism  266  may be disposed at various locations (e.g., on a sidewall  268 , the end wall  272 , the upper end wall  290 , the second cavity  256 , etc.) such that the latching mechanism  266  engages corresponding features on the battery pack  254  (e.g., a slot  382 ) to maintain engagement between the battery pack  254  and the battery-receiving portion  250 . 
     With specific reference to  FIGS.  15 - 17   , the battery-receiving portion  250  includes first grooves  258 A defined by first rails  298 A disposed along a portion of the sidewalls  268  of the first cavity  252  from the open end  286  to the first end wall  272 . Second grooves  258 B are defined by second rails  298 B disposed along a portion of the sidewalls  268  of the second cavity  256  from second end wall  284  toward the third end wall  288 . The illustrated rails  298 A,  298 B are collinear and collectively define a single battery sliding axis  394 . 
     Device contacts  294  are supported on the end wall  290  and configured to receive battery contacts  354 . An ejector  338  is configured to provide assisted removal of the battery pack  254  along the battery sliding axis  394 . 
       FIGS.  18 - 19    illustrate the battery pack  254  for use with the battery-receiving portion  250 , described above. The battery pack  254  includes a housing  350  supporting one or more battery cells (not shown) coupled to the battery contacts  354 . 
     The battery pack  254  includes a first protrusion  400  and a second protrusion  404  defined on the housing  350 . Each protrusion  400 ,  404  has lateral sides  408 , each including a rail  412  outwardly therefrom to define a groove  416 . The first protrusion  400  further includes a surface  420  defining the slot  382  to receive the latch member  314 . The rails  412  of the first protrusion  400  and the second protrusion  404  are collinear and sized and shaped to be received by the grooves  258 A,  258 B defined within the first cavity  252  and the second cavity  256 , respectively. 
     With reference to  FIGS.  20 A- 20 C , the latching mechanism  266  is substantially similar to the latching mechanism  66  described above. However, in this embodiment, a switch  334  is not engaged until the latch member  314  is nearly removed from the first cavity  252 . The intermediate position ( FIG.  20 B ) may, for example, correspond to the latching member  314  being approximately 55% to 95% removed from the first cavity  252 . 
     As illustrated in  FIG.  14   -20C, the battery-receiving portion  250  and the battery pack  254  provide a “drop and slide” configuration. That is, to attach the battery pack  254  to the battery-receiving portion  250 , the battery  254  is first “dropped” into the battery-receiving portion  250  along a vertical axis such that the first protrusion  400  and the second protrusion  404  drop into the first cavity  252  and the second cavity  256 , respectively. Subsequently, the battery pack  254  “slides” along the battery sliding axis  394  to initiate coupling and latching in a similar manner as described above with respect to  FIG.  1   -13B. In addition, decoupling or removal and ejection of the battery pack  254  is similar to the procedure described above with respect to  FIG.  1   -13B. 
       FIGS.  21 - 23  and  27 - 28    illustrate an alternate construction of a battery-receiving portion  550  of an electrical device configured to receive a corresponding battery pack  554  ( FIGS.  24 - 28   ). The battery-receiving portion  550  and the corresponding battery pack  554  are similar to the battery-receiving portions  50 ,  250  and the battery pack  54 ,  254  shown in  FIG.  1   -13B and 14-20C, respectively. Common elements have the same reference number plus “500” from the battery-receiving portion  50  and the battery pack  54  and the same reference numeral plus “300” from the battery-receiving portion  250  and the battery pack  254 . 
     The following description will focus on aspects of the battery-receiving portion  550  and the battery pack  554  different than the battery-receiving portions  50 ,  250  and the battery pack  54 . It should be noted, however, that features of the battery-receiving portion  550  or the battery pack  554  may be incorporated or substituted into the battery-receiving portions  50 ,  250  or the battery pack  54 ,  254 , or vice versa. 
     With specific reference to  FIGS.  21 - 23   , the illustrated battery-receiving portion  550  includes stepped grooves  558  extending along a portion of the sidewalls  578  between the open end  586  and the end wall  582  (e.g., as illustrated, from near the open end  586  to the end wall  582 ). In other embodiments (not shown), the grooves  558  may be substantially linear. The stepped grooves  558  are defined by rails  598  disposed on the sidewalls  578 . The rails  598  protrude from the sidewalls  578  to define an upper extent of the grooves  558  that face the lower surface  574 . As seen in  FIGS.  21 - 23   , the rails  598  do not extend along a portion of the sidewalls  578  proximate the open end  586  such that a widened portion  592  is defined at the open end  586 . 
     In the illustrated embodiment (see  FIG.  22   ), a stepped configuration is provided laterally between the opposite rails  598 . The rails  598  include a number of (e.g., two) generally parallel axially-extending portions  607  defining distinct lateral clearances L 1 ′, L 2 ′, ...Ln′ therebetween. Each portion is connected to an angled portion  608  extending obliquely toward the opposite rail  598  (e.g., when moving from right to left in  FIG.  22   ) such that the opposite portions  607  define a successively smaller lateral clearance, thereby forming the “stepped” configuration between the rails  598 . In addition, a lateral clearance L′ is provided between the sidewalls  578  in the widened portion  592  at the open end  586 . In other embodiments (not shown), the rails  598  may include more than two portions  607 . 
       FIGS.  24 - 26    illustrate a battery pack  554  for use with the battery-receiving portion  550 , described above. As will be described in greater detail below, the battery pack  554  includes mechanical features configured to engage corresponding features on the battery-receiving portion  550  to couple and maintain engagement of the battery-receiving portion  550  and the battery pack  554 . 
     In the illustrated embodiment, the rails  666  include a number of (e.g., three) parallel horizontal portions  686  and the body of the housing  650  includes a number of (e.g., two) projections  652  defining pads or flat surfaces  656  facing the rails  666 . The grooves  670  are defined by distinct vertical clearances C 4 ′, C 5 ′, C 6 ′...Cn′ of the grooves  670  measured between each horizontal portion  686  and the flat surfaces  656  (e.g., C 4 ′ and C 6 ′) or the body of the housing  650  (e.g., C 5 ′). Each portion  686  is connected by an angled portion  690  extending obliquely away from the housing  650  when moving from the rear end  674  toward the front end  658 . As illustrated, the rails  666 /grooves  670  of the battery pack  554  form a mated engagement between the rails  598 /grooves  558  of the battery-receiving portion  550 . 
     The illustrated battery pack  554  includes a pair of slots  682   a ,  682   b  on the surface  678  configured to receive the latching member  614 . When battery pack  554  is connected to the battery-receiving portion  550  and the latching mechanism  66 ,  266  is engaged, the latch member  114 ,  314  engages the slot  682   a . When the latch member  114 ,  314  is disengaged from the slot  682   a , as the battery pack  554  is removed from the battery-receiving portion  550 , the latch member  114 ,  314  will engage the slot  682   b  if the handle  110 ,  310  is no longer actuated/has been released. This re-engagement of the latch member  114 ,  314  may inhibit the battery pack  554  from being disconnected inadvertently (e.g., if the handle  110 ,  310  was inadvertently actuated). 
     A horizontal clearance is measured from the lateral side  662  to a periphery of each rail  666 . In the illustrated embodiment (see  FIG.  26   ), a stepped configuration is provided laterally between the opposite rails  666 . The rails  666  include a number of (e.g., three) generally parallel axially-extending portions  691  defining distinct lateral dimensions L 4 ′, L 5 ′, L 6 ′...Ln′ therebetween. Each portion is connected to an angled portion  692  extending obliquely toward the opposite rail  666  (e.g., when moving from right to left in  FIG.  26   ) such that the opposite portions  691  define a successively smaller lateral dimension, thereby forming the “stepped” configuration between the rails  666 . In the illustrated embodiment, the lateral dimension L 4 ′, L 5 ′, L 6 ′ between each portion  691  changes by a constant amount. 
     Again, it should be understood that, if the size, shape, orientation, etc. of the battery-receiving portion  550  is modified, corresponding variations in the size, shape, orientation, etc. of the battery pack  554  may be made. 
       FIGS.  27 - 28    illustrate a mating portion of the battery pack  554  (e.g., the battery pack  554  with the body of the housing  560  removed) being coupled to the battery-receiving portion  550 . As illustrated, the rails  666  of the battery pack  554  are aligned with the grooves  558  of the battery-receiving portion  550 , and, subsequently, the battery pack  554  slides along a battery insertion axis  694  until the device contacts  594  engage the battery contacts  654 . 
     The widened portion  592  may facilitate insertion of the battery pack  554  by providing extra clearance at the open end  586  to reduce the difficulty in aligning the rails  666  of the battery pack  554  with the grooves  558  of the battery-receiving portion  550 . Likewise, the larger relative clearances defined between the rails  666  and the grooves  558 , which decrease as the battery pack  554  is inserted further onto the battery-receiving portion  550 , may also facilitate insertion of the battery pack  554  while providing a tighter, more secure engagement between the battery pack  554  and the battery-receiving portion  550  by creating tighter clearances (e.g., at C 4 ′ and C 6 ′) at full insertion of the battery pack  554 . 
       FIG.  29    illustrates an alternative construction of a slide-actuated latching mechanism  566 . The latching mechanism  566  may be used with one of the battery-receiving portions  50 ,  250 ,  550  (e.g., with or in place of latching mechanisms  66 ,  266 ). 
     The illustrated latching mechanism  566  includes a laterally-displaceable actuator or button  610  operatively engaging a latch member  614 . The latch member  614  is pivotally disposed in a cavity  618  (e.g., defined in the lower surface  574 ) and is biased by a biasing member (e.g., a torsion spring  622 , a coil spring, etc.) to protrude through the lower surface  574  and into the cavity  570 . 
     The latch member  614  has an inclined surface  626  (e.g., angled about 30 degrees to about 60 degrees relative to the lower surface  674 ) facing toward the open end  586  and a generally vertically-extending surface  630  (e.g., about -10 degrees to about 10 degrees relative to a vertical axis) facing toward the end wall  582 . 
     The latch member  614  is coupled to the spring  622  and includes an end  632  coupled to the button  610  (e.g., via a cam surface). The button  610  is engaged with the latch member  614  such that actuation (e.g., pressing the button to effect lateral displace to the left in  FIG.  29    to reach the position illustrated in  FIG.  29   ) of the button  610  causes the latch member  614  to pivot against the bias of the spring  622  to withdraw the latch member  614  from the cavity  570 . 
     The illustrated latching mechanism  566  also includes a switch  634  (e.g., a micro-switch  634 ) facilitating electrical coupling/decoupling of the battery pack  554  during actuation of the button  610  to withdraw the latch member  614  from the cavity  570 . In other embodiments, however, the switch  634  may be omitted. As described above in greater detail, the switch  634  may act to electrically decouple the battery pack  554  from the battery-receiving portion  550  and the device prior to removal of the battery pack  554  from the battery-receiving portion  550 . 
     As the latch member  614  is moved from the latched position (not shown but similar to the position shown in  FIG.  12 A ) to an intermediate position (not shown but similar to the position shown in  FIG.  12 B ), the switch  634  is activated to inhibit the transfer of electrical power between the battery pack  554  and the device before the battery pack  554  is released by the latching member  614  and removable from the battery-receiving portion  550  and before the contacts  654 ,  594  disengage. Activation of the switch  634  to stop power transfer between the battery pack  554  and the device may, for example, prevent arcing between the contacts  654 ,  594  as the battery pack  554  is removed. 
     Further movement of the latching member  614  to an unlatched position ( FIG.  29   ) removes the latching member  614  from the slot  682   a ,  682   b , and the battery pack  554  is permitted to move along the battery insertion axis  694  off of the battery-receiving portion  550 . The switch  634  is maintained in the on position to continue inhibiting the transfer of power between the battery pack  554  and the device. 
     It should be understood that, in other constructions (not shown), features described as being on one of the battery-receiving portion  50 ,  250 ,  550  and the battery pack  54 ,  254 ,  554  (e.g., the stepped grooves  58 ,  558 , the “drop and slide” arrangement, the latching mechanism  66 ,  566 , the ejector  138 , etc.) may be provided on the other of the battery-receiving portion  50  and the battery pack  54 . 
       FIGS.  30 - 33    illustrate an alternate construction of a battery-receiving portion  750  of an electrical device configured to receive a corresponding battery pack  754  ( FIGS.  38 - 40   ). The battery-receiving portion  750  and the corresponding battery pack  754  are similar to the battery-receiving portions  50 ,  250 ,  550  and the battery pack  54 ,  254 ,  554  shown in  FIG.  1   -13B, 14-20C, and 21-29, respectively. Common elements have the same reference number plus “700” from the battery-receiving portion  50  and the battery pack  54 , the same reference numeral plus “500” from the battery-receiving portion  250  and the battery pack  254 , and the same reference numeral plus “200” from the battery-receiving portion  550  and the battery pack  554 . 
     The following description will focus on aspects of the battery-receiving portion  750  and the battery pack  754  different than the battery-receiving portions  50 ,  250 ,  550  and the battery pack  54 ,  254 ,  554 . It should be noted, however, that features of the battery-receiving portion  750  or the battery pack  754  may be incorporated or substituted into the battery-receiving portions  50 ,  250 ,  550  or the battery pack  54 ,  254 ,  554 , or vice versa. 
     With reference to  FIGS.  30 - 33   , the battery-receiving portion  750  is substantially similar, in particular, to the battery-receiving portion  550  illustrated in  FIGS.  21 - 29   . However, the battery-receiving portion  750  further includes a dual-action latching mechanism  766 . In other words, in order to operate the latching mechanism  766  to release the battery  754  from the battery-receiving portion  750 , two separate actions are required. 
     As shown in  FIGS.  30 - 33   , the latching mechanism  766  includes a primary actuator or handle  810  that supports a secondary actuator  812 . The secondary actuator  812  includes a user interface  816  on a first end and a housing engaging portion  820  on an opposite end. 
     The secondary actuator  812  is pivotable between a first position, in which the housing engaging portion  820  engages a portion of the lower surface  774 , and a second position, in which the housing engaging portion  820  extends into a groove or aperture  776  in the portion of the lower surface  774 . The secondary actuator  812  is biased toward the first position by a biasing member  824  (e.g., a torsion spring, etc.) to maintain engagement with the lower surface  774 . 
     In the first position, the engagement of the engaging portion  820  and the lower surface  774  inhibits or prevents movement (e.g., pivoting) of the actuator  810  to prevent unlatching of the battery pack  754 . A user can apply a force to the user interface  816  to pivot the secondary actuator (e.g., in a counterclockwise direction in  FIG.  33   ) against the bias of the biasing member  824  into the second position. In the second position, the engaging portion  820  no longer engages the lower surface  774  and is instead aligned with the groove  776  thereby providing clearance for the actuator  810  to pivot and unlatch the battery pack  754 , as described in greater detail below. 
     The actuator  810  operatively engages the latch member  814 . The latch member  814  is slidably disposed in a bore  818  defined in the lower surface  774  and is biased by two biasing members (e.g., springs  822 , such as a coil spring, a torsion spring, etc.) to protrude through the lower surface  774  and into the cavity  770 . As seen in  FIG.  32   , the biasing springs  822  are located beneath opposing lateral sides of the latch member  814 . The latch member  814  has an inclined surface  826  (e.g., angled about 30 degrees to about 60 degrees relative to the lower surface  774 ) facing toward the open end  786  and a generally vertically-extending surface  830  (e.g., about -10 degrees to about 10 degrees relative to a vertical axis) facing toward the end wall  782 . 
     The latch member  814  is coupled to the springs  822 . In some embodiments (not shown), one spring  822  may be coupled to the latch member  814  instead of two. In other embodiments (not shown), three or more springs  822  may be coupled to the latch member  814 . In such multi-spring arrangements, each spring  822  may be smaller/shorter, leading to a shorter overall height of the latch member  814  and the spring  822  without a reduction in biasing force. 
     The handle  810  is engaged with the latch member  814  via a cam surface  831  such that actuation (e.g., clockwise pivoting/rotation of the handle  810  with respect to the position shown in  FIG.  33   ) of the handle  810  causes the latch member  814  to translate downwardly against the bias of the springs  822  to withdraw the latch member  814  from the cavity  770 . 
     The latching mechanism  766  also includes a switch  834  (e.g., a micro-switch  834 ) facilitating electrical coupling/decoupling of the battery pack  754  during actuation of the handle  810  to withdraw the latch member  814  from the cavity  70 . In other embodiments (not shown), the switch  834  may be omitted. The switch  834  may act to electrically decouple the battery pack  754  from the battery-receiving portion  750  and the device prior to removal of the battery pack  754  from the battery-receiving portion  750 . The operation of a similar switch  134  was described in greater detail with respect to  FIGS.  12 A- 12 C . 
     As seen in the foregoing description, the dual-action latching mechanism  766  requires a user to perform two actions in order to unlatch the battery pack  754 . More specifically, the user must operate the secondary actuator  812  into the second position before the actuator  810  may be operated to remove the latch member  814  from the cavity  770 , to thereby unlatch the battery pack  754 . Such a mechanism can, for example, prevent or reduce the likelihood of unintended unlatching of the battery pack  754  from the battery-receiving portion  750 . 
     It should be understood that, in other constructions (not shown), features described as being on one of the battery-receiving portion  50 ,  250 ,  550 ,  750  and the battery pack  54 ,  254 ,  554 ,  754  (e.g., the stepped grooves  58 ,  558 , the “drop and slide” arrangement, the latching mechanism  66 ,  566 , the ejector  138 , etc.) may be provided on the other of the battery-receiving portion  50 ,  250 ,  550 ,  750  and the battery pack  54 ,  254 ,  554 ,  754 . 
       FIGS.  34 - 37    illustrate an alternate construction of a battery-receiving portion  950  of an electrical device configured to receive a corresponding battery pack  754  ( FIGS.  38 - 40   ). The battery-receiving portion  950  is similar to the battery-receiving portions  50 ,  250 ,  550 ,  750  shown in  FIG.  1   -13B, 14-20C, 21-29, and 30-33, respectively. Common elements have the same reference number plus “900” from the battery-receiving portion  50 , the same reference numeral plus “700” from the battery-receiving portion  250 , the same reference numeral plus “400” from the battery-receiving portion  550 , and the same reference numeral plus “200” from the battery-receiving portion  750 . 
     The following description will focus on aspects of the battery-receiving portion  950  different than the battery-receiving portions  50 ,  250 ,  550 ,  750 . It should be noted, however, that features of the battery-receiving portion  950  may be incorporated or substituted into the battery-receiving portions  50 ,  250 ,  550 ,  750 , or vice versa. 
     With reference to  FIGS.  34 - 37   , the battery-receiving portion  950  is substantially similar, in particular, to the battery-receiving portion  550 ,  750  illustrated in  FIGS.  21 - 29  and  30 - 33   , respectively. However, the battery-receiving portion  950  further includes an alternate embodiment of a dual-action latching mechanism  966 . To operate the dual-action latching mechanism  966  to release the battery  754  from the battery-receiving portion  950 , two separate actions are required. 
     As shown in  FIGS.  34 - 37   , the latching mechanism  966  includes a primary actuator or handle  1010  that supports a linearly displaceable secondary actuator  1012 . The secondary actuator  1012  includes a user interface  1016  and a housing engaging portion  1020 . The secondary actuator  1012  is linearly displaceable (e.g., slidable) between a first position, in which the housing engaging portion  1020  engages a portion of the lower surface  974 , and a second position, in which the housing engaging portion  1020  extends into a groove or aperture  976  in the portion of the lower surface  974 . The secondary actuator  1012  is biased into the first position by a biasing member  1024  (e.g., a coil spring, etc.) to maintain engagement with the lower surface  974 . 
     In the first position, the engagement of the engaging portion  1020  and the lower surface  974  inhibits or prevents movement (e.g., pivoting) of the actuator  1010  to prevent unlatching of the battery pack  754 . A user can apply a force to the user interface  1016  to displace the secondary actuator against the bias of the biasing member  1024  into the second position. In the second position, the engaging portion  1020  no longer engages the lower surface  974  and is instead aligned with the groove  976  thereby providing clearance for the actuator  1010  to pivot and unlatch the battery pack  754 , as described in greater detail below. 
     The pivotable actuator  1010  operatively engages the latch member (not illustrated in this embodiment but similar to the latch member  814 ). The latch member is slidably disposed in a bore  1018  defined in the lower surface  974  and is biased by two biasing members (e.g., springs, such as a coil spring, a torsion spring, etc.) to protrude through the lower surface  974  and into the cavity  970 . The biasing springs  1022  are located beneath opposing lateral sides of the latch member. The latch member has an inclined surface  1026  (e.g., angled about 30 degrees to about 60 degrees relative to the lower surface  974 ) facing toward the open end  986  and a generally vertically-extending surface  1030  (e.g., about -10 degrees to about 10 degrees relative to a vertical axis) facing toward the end wall  982 , similar to the latch members  114 ,  614 ,  814 . 
     The latch member is coupled to the springs  1022 . In some embodiments (not shown), one spring  1022  may be coupled to the latch member instead of two. In other embodiments (not shown), three or more springs  1022  may be coupled to the latch member. In such multi-spring arrangements, each spring  1022  may be smaller/shorter, leading to a shorter overall height of the latch member and the spring  1022  without a reduction in biasing force. 
     The handle  1010  is engaged with the latch member via a cam surface  1030  such that actuation (e.g., clockwise pivoting/rotation of the handle  1010  with respect to the position shown in  FIG.  36   ) of the handle  1010  causes the latch member to translate downward against the bias of the springs  1022  to withdraw the latch member from the cavity  970 . 
     The latching mechanism  966  also includes a switch (e.g., a micro-switch; not shown but similar to the switch  834 ) facilitating electrical coupling/decoupling of the battery pack  754  during actuation of the handle  1010  to withdraw the latch member  1014  from the cavity  970 . In other embodiments (not shown), the switch may be omitted. The switch may act to electrically decouple the battery pack  754  from the battery-receiving portion  950  and the device prior to removal of the battery pack  754  from the battery-receiving portion  950 . The operation of a similar switch  134  was described in greater detail with respect to  FIGS.  12 A- 12 C . 
     As seen in the foregoing description, the dual-action latching mechanism  966  requires a user to perform two actions in order to unlatch the battery pack  754 . More specifically, the user must operate the secondary actuator  1012  into the second position before the actuator  1010  may be operated to remove the latch member from the cavity  970 , to thereby unlatch the battery pack  754 . Such a mechanism can, for example, prevent or reduce the likelihood of unintended unlatching of the battery pack  754  from the battery-receiving portion  950 . 
     It should be understood that, in other constructions (not shown), features described as being on one of the battery-receiving portion  50 ,  250 ,  550 ,  750 ,  950  and the battery pack  54 ,  254 ,  554 ,  754  (e.g., the stepped grooves  58 ,  558 , the “drop and slide” arrangement, the latching mechanism  66 ,  566 , the ejector  138 , etc.) may be provided on the other of the battery-receiving portion  50 ,  250 ,  550 ,  750 ,  950  and the battery pack  54 ,  254 ,  554 ,  754 . 
       FIGS.  38 - 40    illustrate the battery pack  754  for use with the battery-receiving portion  750 ,  950 , described above. As will be described in greater detail below, the battery pack  754  includes mechanical features configured to engage corresponding features on the battery-receiving portion  750 ,  950  to couple and maintain engagement of the battery-receiving portion  750 ,  950  and the battery pack  754 . 
     In the illustrated embodiment, the rails  866  include a number of (e.g., three) parallel horizontal portions  886  and the body of the housing  850  includes a number of (e.g., two) projections  852  defining pads or flat surfaces  856  facing the rails  866 . The grooves  870  are defined by distinct vertical clearances C 4 ″, C 5 ″, C 6 ″...Cn″ of the grooves  870  measured between each horizontal portion  886  and the flat surfaces  856  (e.g., C 4 ″ and C 6 ″) or the body of the housing  850  (e.g., C 5 ″). Each portion  886  is connected by an angled portion  890  extending obliquely away from the housing  850  when moving from the rear end  874  toward the front end  858 . As illustrated, the rails  866 /grooves  870  of the battery pack  754  form a mated engagement between the rails  798 ,  998 /grooves  758 ,  958  of the battery-receiving portion  750 ,  950 . 
     A horizontal clearance is measured from the lateral side  862  to a periphery of each rail  866 . In the illustrated embodiment (see  FIG.  40   ), a stepped configuration is provided laterally between the opposite rails  866 . The rails  866  include a number of (e.g., three) generally parallel axially-extending portions  891  defining distinct lateral dimensions L 4 ″, L 5 ″, L 6 ″ ...Ln″ therebetween. Each portion is connected to an angled portion  892  extending obliquely toward the opposite rail  866  (e.g., when moving from right to left in  FIG.  40   ) such that the opposite portions  891  define a successively smaller lateral dimension, thereby forming the “stepped” configuration between the rails  866 . In the illustrated embodiment, the lateral dimension L 4 ″, L 5 ″, L 6 ″ between each portion  891  changes by a constant amount. 
     With reference to  FIG.  40   , the battery pack  754  includes a single slot  882 . The slot  882  is sized and shaped to receive and engage latch member  814 ,  1014  to prevent removal of the battery pack  754  when the battery pack  754  is attached to the battery-receiving portion  750 ,  950 . 
       FIGS.  41 - 43    illustrate an electrical device, such as a battery charger, including a battery-receiving portion  1150 . As illustrated, the battery-receiving portion  1150  has a “stepped” configuration provided by stepped rails  1158 , similar to the stepped rails  58 ,  558 ,  758 ,  958 , described above, and configured to receive a battery pack with a complementary configuration, such as the battery pack  54 ,  554 ,  754 . When connected, the battery charger is operable to charge the battery pack  54 ,  554 ,  754 . 
     In other constructions (not shown), the battery-receiving portion  1150  may have a different configuration, such as a “drop and slide” configuration similar to the battery-receiving portion  250 , described above, and be configured to receive a battery pack having a complementary configuration, such as the battery pack  254 . 
       FIGS.  44 A- 44 I  and  FIGS.  49 A- 49 H  illustrate alternative constructions of the battery pack  1254  and  1554 , respectively. The battery packs  1254  and  1554  are similar to the battery  54  described above. Common elements have the same reference number plus “1200” or “1500” respectively, from the battery pack  54 . The battery packs  1254  or  1554  may include features of the battery packs  54 ,  254 ,  554 ,  754 . 
     Each battery pack  54 ,  254 ,  554 ,  754 ,  1254 ,  1554  may include one or more cell strings, each having a number (e.g., 5,  10 ,  20 , etc.) of battery cells connected in series to provide a desired discharge output (e.g., nominal voltage (e.g., 20 V, 40 V, 60 V, 80 V, 120 V) and current capacity). In the illustrated construction, the battery pack  1254  includes one string of 20 series connected cells (a “20S1P” configuration), while the battery pack  1554  includes two strings, each having 20 series connected cells (a “20S2P” configuration). 
     Due to the higher number of cells used in the battery pack (e.g., the battery pack  1254 ), the size/weight of the electrical device, the battery pack  1254  may be more vulnerable to damage. In some constructions (see, for example,  FIG.  45   -48F), the battery-receiving portion  50  and/or the battery pack  1254  may be constructed with one or more of the below-described structures to improve impact resistance. 
     In one example, as shown in  FIG.  45   , the housing  1350  of the battery pack  1254  may be constructed with one or more angled surfaces  1400  to remove or soften corner shapes. As a result, rather than impacting a sharp or square corner, the battery pack  1254  may impact on a flat or blunt surface. The angled surface(s)  1400  may increase the strength of the battery pack  1254  during impact of loading. 
     In another example (see  FIGS.  46 A- 46 B ), the battery pack  1254  may include elastomeric overmold material  1410  covering surfaces most likely to be impacted (e.g., exposed edges  1414  of the housing  1350 ). The overmold material  1410  may include an elastomeric material such as a thermoplastic elastomer (TPE), polyurethane, rubber, reduce a load experienced during an impact or drop (e.g., a force up to about 250 Joules or more). As shown in  FIG.  46 B , in the illustrated construction, the overmold material  1410  is thickest (e.g., about 4 mm or more) along the exposed edges  1414  of the housing  1350  and tapers away from these locations (e.g., to a thickness of about 1 mm or less). 
     In yet another example (see  FIGS.  47 A- 47 B ), material of the interface between a battery pack  1254  (e.g. the housing  1350 , the protrusion  1348  and the rails  1366 ) and/or the associated electrical device (e.g., the battery-receiving portion  50 , the side walls  78  and the rails  98 ) may be reinforced. In the illustrated construction, the material of the housing  1350  and of the battery-receiving portion  50  includes plastic, and the reinforcement  1420  is formed of metal. As illustrated, the reinforcement  1420  is molded with the material of the housing  1350  or of the battery-receiving portion  50 . The reinforcement  1420  may contribute to improved impact resistance and drop strength, resistance to material fatigue from vibration, etc. 
       FIGS.  47 A- 47 B  illustrate reinforcement of the interface of the battery pack  1254 . The reinforcement  1420  is provided in areas of the rails  1366  and the protrusion  1348 . The illustrated reinforcement  1420  includes a stamping  1424  including portions following the cross-section of the rails  1366 , forming a generally C-shape around the grooves  1370 . The stamping  1424  also spans the width of the protrusion  1348 . In the illustrated construction, the stamping  1424  is tied directly to bosses  1428  in the housing  1350 . 
     In a further example (see  FIGS.  48 A- 48 F ), a shock absorption arrangement  1440  may be provided between the battery pack  1254  and the electrical device. The arrangement  1440  may provide impact or drop isolation for the battery pack  1254  by providing shock absorbing cushions in the interface. The arrangement  1440  may be provided for shock rather than vibration isolation and provides isolation in all directions. 
     As shown in  FIGS.  48 A and  48 E , the battery-receiving portion  50  is provided by a housing  1444  defining on its outer surface a number of locations (e.g., recesses  1448 ). A projection or post  1452  is supported at each location (e.g., extends from each recess  1448 ). A shock absorption member  1456  is supported on each post  1452 . 
     An outer housing  1460  (see  FIGS.  48 B- 48 E ) and at least partially surrounds the housing  1444 . The housing  1460  defines a corresponding number of locations (e.g., recesses  1464 ), each receiving a shock absorption member  1456 . 
     The shock absorption members  1456  are generally puck-shaped and, in the illustrated construction, are formed of an elastomeric material, such as polyurethane. As shown in  FIG.  48 F , the shock absorption members  1456  may have different constructions, depending on the electrical device, the location in the arrangement  1440 . 
     Thus, the invention may provide, among other things, an interface for a battery pack including a stepped arrangement or a drop and slide configuration. A latching mechanism with a switch to selectively electrically couple and decouple the battery pack and the electrical device may be provided. An ejection mechanism with a switch to selectively activate and deactivate a portion of the electrical device may be provided. 
     Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of one or more independent aspects of the invention as described. 
     One or more independent features and/or independent advantages may be set forth in the following claims.