Abstract:
A battery life extender ( 12 ) for a portable lighting device ( 10 ) employs a reconfigurable mechanism operable to selectively electrically isolate one or more batteries ( 20 ) from a circuit having a parasitic power drain. For example, a lighting device ( 10 ) includes a light generating element ( 14 ), at least one battery ( 20 ), a user operated switch ( 16 ) configured to control delivery of electrical power from the at least one battery ( 20 ) to the light generating element ( 14 ), and a housing assembly ( 18 ) supporting the at least one battery ( 20 ) and the light generating element ( 14 ). The user operated switch ( 16 ) can impart a parasitic power drain. The housing assembly ( 18 ) is reconfigurable to: (a) a first configuration in which the user operated switch ( 16 ) is electrically connected to the at least one battery ( 20 ), and (b) a second configuration in which the at least one battery ( 20 ) is electrically isolated and the at least one battery ( 20 ) is retained by the housing assembly ( 18 ).

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Application No. 61/915,072, filed on Dec. 12, 2013, and also claims the benefit of U.S. Provisional Application No. 61/970,062, filed Mar. 25, 2014, the full disclosures of which are incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Portable electrically powered devices such as flashlights are typically battery powered. In many instances, an extended period of time may pass between usages of a battery powered device. Many battery powered devices, however, may consume battery power at a low, even parasitic rate, even when not being used. For example, a flashlight may include an electronic switch that consumes battery power at a parasitic rate even when the flashlight is not being used. Although such a low rate of consumption of battery power may not significantly discharge the batteries of a portable device over a short period of time, such a parasitic power drain over an extended period of time may discharge the batteries enough to leave inadequate battery power to operate the portable device. 
       BRIEF SUMMARY 
       [0003]    The following presents a simplified summary of some embodiments of the invention in order to provide a basic understanding of the invention. This summary is not an extensive overview of the invention. It is not intended to identify key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some embodiments of the invention in a simplified form as a prelude to the more detailed description that is presented later. 
         [0004]    Approaches and devices for extending the life of batteries used to power portable devices are provided. In many embodiments, a mechanism is provided that is selectively reconfigurable between a first configuration in which a power supply circuit of a portable device is not interrupted and a second configuration in which the power supply circuit of the portable device is interrupted so as to prevent discharge of at least one battery used to power the portable device. The mechanism can be reconfigured by a user of the portable device based upon whether the portable device may not be used for an extended period of time, or whether the portable device is going to be used. For example, the mechanism can be reconfigured from the first configuration to the second configuration when the portable device may not be used for an extended period of time. And the mechanism can be reconfigured from the second configuration to the first configuration prior to use of the portable device. By having the mechanism in the second configuration when the portable device may not be used for an extended period of time, discharge of the at least one battery of the portable device during the extended period of time can be avoided. 
         [0005]    In embodiments described herein, the portable battery powered devices are flashlights. It should be understood, however, that the approaches and mechanisms described herein can be applied to other types of portable battery powered devices. For example, the approaches and mechanisms described herein can be applied to other lighting devices (e.g., headlamps, lanterns, spotlights, etc.). Moreover, the approaches and mechanisms described herein can be applied to suitable battery powered devices (e.g., any suitable fan, pump, radio, speaker, tool, etc.). 
         [0006]    Thus, in one aspect, a lighting device is disclosed that includes a mechanism that is selectively reconfigurable to prevent discharge of battery power. The lighting device includes a light generating element, at least one battery, a user operated switch, and a housing assembly. The user operated switch is configured to control delivery of electrical power from the at least one battery to the light generating element. The housing assembly supports the at least one battery and the light generating element. The housing assembly is reconfigurable to: (a) a first configuration in which the user operated switch is electrically connected to the at least one battery, and (b) a second configuration in which the at least one battery is electrically isolated and the at least one battery is retained by the housing assembly. In many embodiments, the user operated switch includes an electronic switch that consumes power when the housing assembly is in the first configuration. 
         [0007]    In many embodiments of the lighting device, the housing assembly includes a first housing component and a second housing component coupled with the first component in each of the first and second configurations. The second housing component is repositionable relative to the first housing component to allow selective reconfiguration of the housing assembly to each of the first and second configurations. For example, repositioning the second housing component relative to the first housing component to reconfigure the housing assembly to each of the first and second configurations can include rotating and/or translating the second housing component relative to the first housing component. 
         [0008]    The reconfiguration of the housing from the second configuration to the first configuration can result in relative translation between the first and second housing components so as to electrically connect the user operated switch with the at least one battery such that the user operated switch is electrically connected with each of a positive terminal of the at least one battery and a negative terminal of the at least one battery. The relative translation between the first and second housing components can result in at least one of: (a) a housing positive electrical contact electrically connected to the user operated switch is placed into electrical connection with the positive terminal of the at least one battery; and (b) a housing negative electrical contact electrically connected to the user operated switch is placed into electrical connection with the negative terminal of the at least one battery. The relative translation between the first and second housing components can result in translation of the at least one battery relative to the each of the first and second housing components. 
         [0009]    The lighting device can include a deformable assembly that is used to interrupt a power supply circuit in the lighting device. For example, the deformable assembly can be configured to: (a) apply a biasing force to position the at least one battery relative to the housing assembly so as to prevent the housing negative electrical contact from being placed into electrical connection with the negative terminal of the at least one battery when the housing assembly is in the second configuration; and (b) deform when the housing assembly is reconfigured from the second configuration to the first configuration so as to permit the housing negative electrical contact being placed into electrical connection with the negative terminal of the at least one battery. As another example, the deformable subassembly can be configured to: (a) apply a biasing force to position the at least one battery relative to the housing assembly so as to prevent the housing positive electrical contact from being placed into electrical connection with the positive terminal of the at least one battery when the housing assembly is in the second configuration; and (b) deform when the housing assembly is reconfigured from the second configuration to the first configuration so as to permit the housing positive electrical contact being placed into electrical connection with the positive terminal of the at least one battery. 
         [0010]    The lighting device can include a battery cartridge supporting the at least one battery. The battery cartridge can include a cartridge positive contact in electrical connection with the positive terminal of the at least one battery and a cartridge negative contact in electrical connection with the negative terminal of the at least one battery. The relative translation between the first and second housing components can result in the housing positive contact being brought into contact with the cartridge positive contact and the housing negative contact being brought into contact with the cartridge negative contact. Each of the cartridge positive and negative contacts can be disposed on a side of the battery cartridge that is substantially parallel to the relative translation between the first and second housing components. The lighting device can include both the battery cartridge and the deformable assembly. Each of the cartridge positive and negative contacts can include a spring loaded assembly that accommodates a range of relative positions between the first and second housing components while maintaining electrical connection between the at least one battery and the user operated switch. 
         [0011]    In many embodiments of the lighting device, the housing assembly is configured such that the second housing component is rotatable relative to the first housing component about a rotational axis. The housing assembly can include at least one housing electrical contact electrically connected with the user operated switch and radially offset from the rotational axis. The at least one housing electrical contact can be electrically isolated from the at least one battery when the housing assembly is in the second configuration. The at least one housing electrical contact can be electrically connected with the at least one battery when the housing assembly is in the first configuration. 
         [0012]    In many embodiments of the lighting device, a visual indication is provided that indicates the isolation status of the at least one battery. For example, the lighting device can include an indicator that is viewable by a user when the housing assembly is in the second configuration. 
         [0013]    In another aspect, a battery powered portable device includes a battery powered portion, at least one battery, and electronic switch, a first housing portion, and a second housing portion. The electronic switch is configured to control delivery of electrical power from the at least one battery to the battery powered portion. The electronic switch consumes power when electrically connected with the at least one battery. The first housing portion is configured to at least partially house the at least one battery. The second housing portion is coupled with the first housing portion via a threaded connection. The second housing portion includes an electrical connection assembly that forms part of an electrical connection between the at least one battery and the electronic switch when the second housing portion is in a first position relative to the first housing portion and forms a break in the electrical connection when the second housing portion is in a second position relative to the first housing portion. The second housing portion is closer to the first housing portion when in the second position relative to when in the first position. 
         [0014]    In many embodiments, the electrical connection assembly includes a first electrical contact electrically connected to the electronic switch, a second electrical contact electrically connected to the at least one battery, and a deformable element. The deformable element biases the second electrical contact into contact with the first electrical contact when the second housing portion is in the first position relative to the first housing portion. The deformable element deforms in response to repositioning of the second housing portion into the second position so as to accommodate separation between the first and second electrical contacts. 
         [0015]    The electrical connection assembly can further include a conductive spring connected to the second electrical contact. The spring can contact the at least one battery in each of the first and second positions of the second housing portion relative to the first housing portion. 
         [0016]    In many embodiments, the deformable element includes a deformable material layer having a first side and a second side opposite to the first side. The first side can contact the second electrical contact. The second side can contact an end wall of the second housing portion. 
         [0017]    In another aspect, a battery powered portable device includes a battery powered portion, at least one battery, an electronic switch, and a user operated mechanical switch. The electronic switch is configured to control delivery of electrical power from the at least one battery to the battery powered portion. The electronic switch consumes power when electrically connected with the at least one battery. The user operated mechanical switch is operable to selectively electrically connect the at least one battery to the electronic switch and to electrically isolate the at least one battery from the electronic switch. 
         [0018]    For a fuller understanding of the nature and advantages of the present invention, reference should be made to the ensuing detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]      FIG. 1  shows a flashlight including a battery life extending mechanism, in accordance with many embodiments. 
           [0020]      FIG. 2  shows a cross-sectional view of the flashlight of  FIG. 1  in a configuration in which batteries of the flashlight are electrically isolated. 
           [0021]      FIG. 3  shows a cross-sectional view of the flashlight of  FIG. 1  in a configuration in which batteries of the flashlight are electrically isolated. 
           [0022]      FIG. 4  illustrates the flashlight of  FIG. 1  in the configuration in which the batteries of the flashlight are electrically connected for delivery of electrical power to operate the flashlight. 
           [0023]      FIG. 5  shows a cross-sectional view of a flashlight, in accordance with many embodiments, in a configuration in which both positive and negative terminals of a battery stack are electrically isolated. 
           [0024]      FIG. 6  shows a cross-sectional view of the flashlight of  FIG. 5  in a configuration in which both positive and negative terminals of the battery stack are electrically connected for delivery of electrical power. 
           [0025]      FIG. 7  partially illustrates a flashlight that includes a user operated mechanism operable to selectively connect and disconnect one or more batteries of the flashlight, in accordance with many embodiments. 
           [0026]      FIG. 8  shows a partial cross-sectional view of the flashlight of  FIG. 7  in a configuration in which a non-conducting member of the user operated mechanism separates an electrical contact from a battery terminal. 
           [0027]      FIG. 9  shows a partial cross-sectional view of the flashlight of  FIG. 7  in a configuration in which the non-conducting member of the user operated mechanism does not separate the electrical contact from the battery terminal. 
           [0028]      FIG. 10  shows a partial cross-sectional view of a flashlight in a configuration in which a reconfigurable mechanism including a deformable element forms part of an electrical connection for supplying battery power, in accordance with many embodiments. 
           [0029]      FIG. 11  shows a cross-sectional view of the flashlight of  FIG. 10  in a configuration in which the reconfigurable mechanism forms an interruption in the electrical connection for supplying battery power. 
           [0030]      FIG. 12  through  FIG. 15  schematically illustrate the use of relative rotation between components of a portable device about an axis of rotation to selectively connect and isolate battery terminals, in accordance with many embodiments. 
           [0031]      FIG. 16  shows a user worn headlamp including a battery life extending mechanism, in accordance with many embodiments. 
           [0032]      FIG. 17  shows a cross-sectional view of the headlamp of  FIG. 16  in a configuration in which a battery cartridge of the flashlight is electrically connected for delivery of electrical power to operate the headlamp. 
           [0033]      FIG. 18  shows a cross-sectional view of the headlamp of  FIG. 16  in a configuration in which the battery cartridge of the headlamp are electrically isolated. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    In the following description, various embodiments of the present invention will be described. For purposes of explanation, specific configurations and details are set forth in order to provide a thorough understanding of the embodiments. It will also be apparent to one skilled in the art, however, that the present invention may be practiced without the specific details. Furthermore, well-known features may be omitted or simplified in order not to obscure the embodiment being described. 
         [0035]    Referring now to the drawings, in which like reference numerals represent like parts throughout the several views,  FIG. 1  shows a flashlight  10  that includes a battery life extending mechanism  12 , in accordance with many embodiments. The flashlight  10  includes a light generating element  14 , a user operated switch  16 , and a housing assembly  18 . The housing assembly  18  has an internal volume that accommodates a battery assembly including one or more batteries used to power the flashlight  10 . In many embodiments, the user operated switch  16  includes an electronic switch that consumes battery power when the user operated switch  16  is operatively connected to the one or more batteries. To enable selective electrical isolation of the one or more batteries so as prevent discharge of the one or more batteries via the electronic switch, the battery life extending mechanism  12  is user reconfigurable such that the user can selectively electrically connect the one or more batteries with the user operated switch  16  and electrically isolate the one or more batteries from the user operated switch  16 . 
         [0036]      FIG. 2  shows a cross-sectional view of the flashlight  10  in a configuration in which the battery assembly  20  of the flashlight  10  is electrically isolated from the user operated switch  16 .  FIG. 2  also illustrates additional components of the flashlight  10 . For example, the housing assembly  18  includes a main body  22 , an end cap  24 , a head assembly  26 , and the battery life extending mechanism  12 . The user operated switch  16  includes a push button  28  and a tactile switch  30  that is selectively operated by user depression of the push button  28 . In many embodiments, the tactile switch  30  includes electronic components that may consume a small amount of power from the one or more batteries of the battery assembly  20  when the tactile switch  30  is electrically connected to the one or more batteries of the battery assembly  20 . 
         [0037]    The battery assembly  20  further includes spring loaded contact assemblies  32 ,  34 . In the illustrated embodiment, the spring loaded contact assembly  32  is connected with to one polarity of the one or more batteries (e.g., positive or negative) and the spring loaded contact assemblies  34  are connected to the other polarity (e.g., negative or positive). While the illustrated embodiment of the battery assembly  20  includes two of the spring loaded contact assemblies  34 , a single spring loaded contact assembly  34  can be used. Each of the spring loaded assemblies  32 ,  34  includes a conductive spring  36 ,  38  and a contact member  40 ,  42 . Each of the contact members  40 ,  42  partially accommodates a respective one of the spring  36 ,  38 . The battery assembly  20  further includes a frame member  44  that interfaces with and accommodates each of the contact members  40 ,  42 . Each of the contact members  40 ,  42  is configured to extend past an end face of the frame member  44  by a fixed amount when the flashlight  10  is in the configuration illustrated in  FIG. 2 . For example, each of the contact members  40 ,  42  can have a feature that interfaces with the frame member  44  so as to limit the amount that the contact member  40 ,  42  extends past the frame member  44  under the biasing force supplied by compressive deformation of the respective spring  36 ,  38 . 
         [0038]    The battery assembly  20  further includes a base contact assembly  46 . The base contact assembly  46  interfaces with each of the conductive springs  36 ,  38  and electrically connects the conductive springs  36 ,  38  to respective polarities of the one or more batteries of the battery assembly  20 . When the battery assembly  20  includes two or more batteries, the batteries can be electrically connected in any suitable fashion such as in series, in parallel, or in both series and parallel (e.g., two sets of two series connected batteries with the two sets being connected in parallel). 
         [0039]    The head assembly  26  includes, the light generating element  14 , an external housing member  48 , a reflector  50 , a lens  52 , a lens cap  54 , and an internal frame assembly  56 . The reflector  50  and the lens  52  are supported by the external housing member  48  and retained within the external housing member  48  via the lens cap  54 , which is removably coupled with the external housing member  48  via a threaded connection  58 . The internal frame assembly  56  is coupled to the external housing member  48  via a threaded connection  60  and includes electrical contacts  62 ,  64  that are electrically coupled with a circuit including the light generating element  14  and the tactile switch  30 . The electrical contact  62  is centrally disposed and configured to be selectively be brought into contact with the contact member  40  via selective reconfiguration of the battery life extending mechanism  12 . The electrical contact  64  is annular shaped and configured to be selectively brought into contact with the contact members  42  via selective reconfiguration of the battery life extending mechanism  12 . 
         [0040]      FIG. 3  illustrates relative movement between the head assembly  26  and the housing assembly  18  that is used to reconfigure the battery life extending mechanism  12  between the configuration shown in  FIG. 2  and the configuration show in  FIG. 4 . In the configuration shown in  FIG. 2 , the one or more batteries of the battery assembly  20  are electrically isolated from the circuit including the light generating element  14  and the tactile switch  30 . In the configuration shown in  FIG. 4 , the one or more batteries of the battery assembly  20  are electrically connected with the circuit including the light generating element  14  and the tactile switch  30 . As shown in  FIG. 3 , the external housing member  48  is coupled with the frame member  44  via a threaded connection  66 . By rotating the external housing member  48  relative to the frame member  44 , the head assembly  26  can be controllably translated relative to the frame member  44  so as to selectively bring the centrally disposed contact  62  and the annularly shaped contact  64  into contact with or out of contact with the spring loaded contact assemblies  32 ,  34 . Accordingly, the flashlight  10  can be reconfigured between the configuration shown in  FIG. 2  and the configuration shown in  FIG. 4  via relative rotation of the head assembly  26  relative to the frame member  44 , which is rotationally fixed relative to the main body  22 . 
         [0041]      FIG. 5  shows a cross-sectional view of a flashlight  100 , in accordance with many embodiments, in a configuration in which both positive and negative terminals of a stack of batteries  102  are electrically isolated from a circuit including a light emitting element  14  and a user operated switch controlling delivery of power from the stack of batteries  102  to the light emitting element  14 . The flashlight  100  includes a main housing  104 , an end cap assembly  106 , a head assembly  108 , and a deformable member  110 . The end cap assembly  106  includes an electrical contact  112 . The electrical contact  112  is electrically connected to the circuit including the light emitting element  14  and the user operated switch. In the configuration shown in  FIG. 5 , the deformable member  110  is in an extended configuration that maintains a separation gap  114  between the stack of batteries  102  and the electrical contact  112 . In many embodiments, when the flashlight  100  is in the configuration shown in  FIG. 5 , the deformable member  110  exerts a biasing force on the stack of batteries  102  so as to maintain contact between the stack of batteries  102  and a shoulder feature  116  of the main housing  104 . 
         [0042]    The head assembly  108  includes an external housing member  118 , a reflector  120 , a lens  122 , a lens cap  124 , and an internal frame assembly  126 . The reflector  120  and the lens  122  are supported by the external housing member  118  and retained within the external housing member  118  via the lens cap  124 , which is removably coupled with the external housing member  118  via a threaded connection  128 . The internal frame assembly  126  is coupled to the external housing member  118  via a threaded connection  130  and includes an electrical contact  132  that is electrically coupled with the circuit including the light generating element  14  and the user operated switch. 
         [0043]    The head assembly  108  is selectively repositionable relative to the main housing  104 . In the illustrated embodiment, a selective rotation  134  of the head assembly  108  relative to the main housing  104  can be accomplished by a user to reposition the head assembly  108  in a direction  136 . The selective rotation  134  results in repositioning of the head assembly  108  due to the head assembly  108  being coupled to the main housing  104  via a threaded connection  138 . In the configuration illustrated in  FIG. 5 , the head assembly  108  is positioned relative to the main housing  104  such that a gap exists between the stack of batteries  102  and the electrical contact  132 . The head assembly  108  can be coupled with the main housing  104  such that a desired amount of the selective rotation  134 , for example, 45 to 180 degrees of rotation, is used to reposition the head assembly  108  from the configuration shown in  FIG. 5  to the configuration shown in  FIG. 6 . 
         [0044]    In the configuration illustrated in  FIG. 6 , the head assembly  108  is positioned relative to the main housing  104  such the electrical contact  132  is in contact with the stack of batteries  102  and the head assembly  108  exerts a biasing force onto the stack of batteries  102  sufficient to compress the deformable member  110  and to maintain contact between the stack of batteries  102  and the electrical contact  112 . As can be seen by comparing  FIG. 5  and  FIG. 6 , the head assembly  108  is repositionable so as to displace the stack of batteries  102  relative to the main housing  104  sufficient to compress the deformable member  110  and bring the stack of batteries  102  into contact with the electrical contact  112 . In the configuration shown in  FIG. 6 , the stack of batteries  102  is operatively electrically connected to the circuit including the light emitting element  14  and the user operated switch. 
         [0045]    In the flashlight  100 , repositioning of the head assembly  108  relative to the main housing  104  along the direction  136  is accomplished via the selective rotation  134  in combination with the threaded connection  138 . Alternatively, other suitable approaches for repositioning the head assembly  108  relative to the main housing  104  along the direction  136  can be used. For example, the head assembly  108  can be slideably coupled with the main housing  104  to allow selective translation along the direction  136  between the configurations shown in  FIG. 5  and  FIG. 6 . One or more suitable detent mechanisms can be used to prevent inadvertent relative translation between the head assembly  108  and the main housing  104  so as to selectively maintain each of the configurations shown in  FIG. 5  and  FIG. 6 . 
         [0046]      FIG. 7  partially illustrates a flashlight  200  that includes a user operated mechanism  202 . The user operable mechanism  202  is user reconfigurable to enable selective interruption of a circuit between one or more batteries of the flashlight  200  and a user operated switch used to control delivery of battery power to a light emitting element  14  of the flashlight  200 . 
         [0047]      FIG. 8  shows a partial cross-sectional view of the flashlight  200  in a configuration in which a non-conducting member  204  of the user operated mechanism  202  separates an electrical contact  206  from a battery terminal  208  of one or more batteries of the flashlight  200 . The user operated mechanism  202  is configured to maintain the illustrated position of the non-conducting member  204  absent user interaction with the mechanism  202 . The electrical contact  206  is electrically connected to a circuit including the light emitting element  14  and a user operated switch that controls delivery of battery power to the light emitting element  14 . 
         [0048]      FIG. 9  shows a partial cross-sectional view of the flashlight  200  in a configuration in which the non-conducting member  204  of the user operated mechanism  202  does not separate the electrical contact  206  from a battery terminal  208  of one or more batteries of the flashlight  200 . The user operated mechanism  202  is configured to maintain the illustrated position of the non-conducting member  204  absent user interaction with the mechanism  202 . 
         [0049]    Alternatively, other approaches can be used to selectively isolate one or more batteries of a flashlight from a circuit including a light emitting element and a user operated switch used to control delivery of battery power to the light emitting element. For example, an additional user operated switch (e.g., a simple on/off single pole, single throw electrical switch) can be incorporated into the circuit including the light emitting element and the user operated switch used to control delivery of battery power to the light emitting element. 
         [0050]      FIG. 10  shows a partial cross-sectional view of a flashlight  300  that includes a light emitting element, a user operable switch controlling delivery of battery power to the light emitting element, one or more batteries  302 , a battery housing  304  and a reconfigurable mechanism  306  coupled with the housing  304 . The reconfigurable mechanism  306  is selectively reconfigurable to electrically isolate the one or more batteries  302  from a circuit including the light emitting element and a user operated switch controlling delivery of battery power to the light emitting element. The mechanism  306  includes an end cap frame  308 , a deformable member  310 , an electrical contact  312 , and a conductive spring  314 . The end cap frame  308  is coupled with the battery housing  304  via a threaded connection  316 . 
         [0051]    In the configuration illustrated in  FIG. 10 , the one or more batteries  302  are electrically connected with the circuit including the light emitting element and the user operated switch controlling delivery of battery power to the light emitting element. The end cap frame  308  is positioned relative to the housing  304  such that a sufficient separation between the one or more batteries  302  and the end cap exits to accommodate a semi-compressed state of the combination of the deformable member  310 , the electrical contact  312 , and the conductive spring  314  in which the electrical contact  312  is held in contact with an electrical contact  318  supported by the end cap frame  308  via a biasing force exerted on the electrical contact  312  by the deformable member  310 . The electrical contact  318  is electrically coupled with the circuit including the light emitting element and the user operated switch controlling delivery of battery power to the light emitting element. 
         [0052]    In the configuration illustrated in  FIG. 11 , the one or more batteries  302  are electrically isolated from the circuit including the light emitting element and the user operated switch controlling delivery of battery power to the light emitting element. The end cap frame  308  is positioned relative to the housing  304  such that a separation between the one or more batteries  302  and the end cap exits to accommodate a compressed state of the combination of the deformable member  310 , the electrical contact  312 , and the conductive spring  314  in which the electrical contact  312  is separated from the electrical contact  318  supported by the end cap frame  308 . 
         [0053]    In the illustrated embodiment, repositioning the end cap frame  308  relative to the battery housing  304  is accomplished via the threaded connection  316  by rotation of the end cap frame  308  relative to the battery housing  304 . Alternatively, other suitable approaches for repositioning the end cap frame  308  relative to the battery housing  304  can be used. For example, the end cap frame  308  can be slideably coupled with the battery housing  304  to allow selective translation between the configurations shown in  FIG. 10  and  FIG. 11 . One or more suitable detent mechanisms can be used to prevent inadvertent relative translation between the end cap frame  308  and the battery housing  304  so as to selectively maintain each of the configurations shown in  FIG. 10  and  FIG. 11 . 
         [0054]      FIG. 12  through  FIG. 15  schematically illustrate the use of relative rotation between components of a flashlight to selectively connect and isolate battery terminals, in accordance with many embodiments.  FIG. 12  schematically illustrates a configuration in which battery terminals  320  are separated from electrical contacts  322 . The electrical contacts  322  are electrically connected to a circuit including a light emitting element and a user operated switch operable to control delivery of battery power to the light emitting element. The batteries  324  of the battery terminals  320  are housed within a battery housing  326 . The battery terminals  320  are radially offset from a centerline axis of the battery housing  326 . In many embodiments, the batteries  324  are restrained from moving radially relative to the battery housing  326 . The electrical contacts  322  are also offset from the centerline axis of the battery housing  326 . The electrical contacts  322  are supported so as to be selectively rotatable relative to the battery housing  326  so as to enable selective separation between the battery terminals  320  and the electrical contacts  322  as depicted in  FIG. 12  and selective engagement between the battery terminals  320  and the electrical contacts  322  as depicted in  FIG. 13 .  FIG. 14  and  FIG. 15  schematically illustrate a similar configuration as illustrated in  FIG. 11  and  FIG. 12 , but with a single battery  324  and terminal  320  and a single electrical contact  322 . 
         [0055]      FIG. 16  shows a user worn headlamp  400  including a battery life extending mechanism, in accordance with many embodiments. The headlamp  400  includes a main assembly  402  and a headband  404  for holding the main assembly  402  in place on a user, such as holding the main assembly  402  in place on a user&#39;s forehead. The main assembly  402  includes one or more light emitting elements  406 . 
         [0056]      FIG. 17  shows a cross-sectional view of the main assembly  402  in a configuration in which one or more batteries of the headlamp  400  are electrically connected for delivery of electrical power to the one or more light emitting elements  406 . The main assembly  402  includes a housing  408 , a battery door  410 , a spring  412 , and a battery cartridge  414 . The battery cartridge  414  houses one or more batteries and includes battery cartridge electrical contacts  416 ,  418 . The battery cartridge electrical contacts  416 ,  418  are electrically connected to respective polarities of the one or more batteries of the battery cartridge  414 . The main assembly  402  includes main assembly electrical contacts  420 ,  422 . The main assembly electrical contacts  420 ,  422  are electrically connected to a circuit that includes the one or more light emitting elements  406  and a user operated switch that controls delivery of battery power from the battery cartridge  414  to the one or more light emitting elements  406 . In the configurations shown in  FIG. 16  and  FIG. 17 , the spring  412  exerts a biasing force onto the battery cartridge  414  thereby maintaining contact between the battery cartridge  414  and the battery door  410 . The battery door  410  is coupled with the housing  408  via a threaded connection  424 . In the configuration illustrated in  FIG. 17 , the battery door  410  is fully installed into the housing  408  via the threaded connection  424 , thereby aligning, and maintaining contact between, the battery cartridge electrical contacts  416 ,  418  and the main assembly electrical contacts  420 ,  422 . In the configuration illustrated in  FIG. 18 , the battery door  410  is partially installed into the housing  408  via the threaded connection  424 , thereby misaligning, and maintaining separation between, the battery cartridge electrical contacts  416 ,  418  and the main assembly electrical contacts  420 ,  422 . By partially installing the battery door  410  as illustrated in the configuration illustrated in  FIG. 18 , parasitic draining of power from the battery cartridge  414  can be prevented during an extended period of time between usages of the headlamp  400 . 
         [0057]    Other variations are within the spirit of the present invention. Thus, while the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof are shown in the drawings and have been described above in detail. It should be understood, however, that there is no intention to limit the invention to the specific form or forms disclosed, but on the contrary, the intention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and scope of the invention, as defined in the appended claims. 
         [0058]    The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. The term “connected” is to be construed as partly or wholly contained within, attached to, or joined together, even if there is something intervening. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate embodiments of the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. 
         [0059]    Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 
         [0060]    All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.