Abstract:
A battery-powered light including a body, a light source and a control circuit. The body includes a battery support portion and houses the light source. The battery support portion is operable to physically support a battery pack. The light source is electrically connectable to the battery pack and able to receive a discharge current from the battery pack. The light source also is operable to emit light. The control circuit is supported by the body and is operable to control the discharge current being supplied to the light source.

Description:
RELATED APPLICATIONS  
       [0001]     This patent application claims the benefit of prior filed, co-pending U.S. provisional patent application Ser. No. 60/625,818, filed Nov. 7, 2004, the entire content of which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention generally relates to a light and, more particularly, to a battery-powered light.  
       SUMMARY OF THE INVENTION  
       [0003]     In some constructions and in some aspects, the invention provides a light having a control circuit to perform various functions to enhance operation of the light. In one construction, the circuit can provide an indication to a user that an incorrect light source is connected to the light. In another construction, the circuit can limit the current being supplied to a light source with a lower voltage rating. In a further construction, the circuit can provide a low voltage detection module. In still a further construction, the circuit can provide a sleep circuit to reduce parasitic current draw.  
         [0004]     In some constructions and in some aspects, the invention provides a battery-powered light including a body and a control circuit. The body includes a battery support portion and houses a light source. The battery support portion is operable to physically support a battery pack. The light source is electrically connectable to the battery pack and able to receive a discharge current from the battery pack. The light source is also operable to emit light. The control circuit is supported by the body and is operable to control the discharge current being supplied to the light source.  
         [0005]     In some constructions and in some aspects, the invention provides a combination including a battery pack and a light. The battery pack includes at least one battery cell operable to supply a discharge current, a first switch operable to interrupt the supply of discharge current, and a first circuit operable to control the switch to interrupt the supply of discharge current and operable to sense at least one battery condition during an interruption of supply of discharge current. The light includes a body housing a light source, a second switch having a conducting state and a non-conducting state, low voltage monitor and a second circuit. The light source is electrically connectable to the battery pack and able to receive the discharge current from the at least one battery cell. The second switch is operable to interrupt the supply of discharge current when in the non-conducting state. The low voltage monitor is operable to sense a voltage of the battery pack and operable to control the second switch to interrupt the supply of discharge current when the voltage of the battery pack is at least one of equal to or less than a predetermined voltage threshold. The a second circuit is operable to sense the interruption of supply of discharge current controlled by the first switch in the battery pack and is operable to prevent the low voltage monitor from controlling the second switch to the non-conducting state when the voltage of the battery pack is approximately less than the predetermined voltage threshold during the interruption of supply of discharge current controlled by the first switch.  
         [0006]     In some constructions and in some aspects, the invention provides a light operable to receive a discharge current from the battery pack. The battery pack has a voltage. The light includes a body housing a light source, a switch and a low voltage monitor. The light source is electrically connectable to a battery pack and able to receive the discharge current from the battery pack. The switch is supported by the body and has a conducting state and a non-conducting state. The switch is operable to interrupt the supply of discharge current when in the non-conducting state. The low voltage monitor is operable to sense a voltage of the battery pack and operable to control the second switch to interrupt the supply of discharge current when the voltage of the battery pack is approximately less than a predetermined voltage threshold.  
         [0007]     Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a front perspective view of a light and a battery.  
         [0009]      FIG. 2  is a rear perspective view of the light and the battery shown in  FIG. 1 .  
         [0010]      FIG. 3  is a side view of the light and the battery shown in  FIG. 1 .  
         [0011]      FIG. 4  is another side view of the light and the battery shown in  FIG. 1 .  
         [0012]      FIG. 5  is a front view of the light and the battery shown in  FIG. 1 .  
         [0013]      FIG. 6  is a rear view of the light and the battery shown in  FIG. 1 .  
         [0014]      FIG. 7  is a top view of the light and the battery shown in  FIG. 1 .  
         [0015]      FIG. 8  is a bottom view of the light and the battery shown in  FIG. 1 .  
         [0016]      FIG. 9  is a front perspective view of another construction of a light.  
         [0017]      FIG. 10  is a rear perspective view of the light shown in  FIG. 9 .  
         [0018]      FIG. 11  is a side view of the light shown in  FIG. 9 .  
         [0019]      FIG. 12  is a front view of the light shown in  FIG. 9 .  
         [0020]      FIG. 13  is rear view of the light shown in  FIG. 9 .  
         [0021]      FIG. 14  is a top view of the light shown in  FIG. 9 .  
         [0022]      FIG. 15  is a rear view of the light shown in  FIG. 9 .  
         [0023]      FIG. 16  is another side view of the light shown in  FIG. 9  and illustrating two orientations of the light.  
         [0024]      FIG. 17  is a front perspective view of another construction of a light and a bit holder.  
         [0025]      FIG. 18  is a schematic diagram of a light and a battery.  
         [0026]      FIG. 19  is a schematic diagram of a circuit included in a light, such as the light shown in  FIGS. 1, 9  and  17 .  
         [0027]      FIG. 20  is a schematic diagram of another construction of a circuit included in a light, such as the light shown in  FIGS. 1, 9  and  17 . 
     
    
     DETAILED DESCRIPTION  
       [0028]     Before any 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 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. The use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. 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. Further, “connected” and “coupled” are not restricted to physical or mechanical connections or couplings.  
         [0029]     A light  40  is illustrated in  FIGS. 9-16  and shown connected to a battery  50  in  FIGS. 1-8 . The light  40  is configured to receive power from a power source, such as, for example, the battery  50 . As shown in  FIGS. 1-8 , the battery  50  is a removable, rechargeable battery. In some constructions and in some aspects, the light  40  can be configured for receiving power from a battery similar to or including features of those batteries shown and described in co-pending U.S. patent application Ser. No. 10/720,027, filed Nov. 20, 2003, entitled METHOD AND SYSTEM OF BATTERY PROTECTION (Attorney Docket No. 066042-9536-01), in co-pending U.S. patent application Ser. No. 10/721,800, filed Nov. 24, 2003, entitled BATTERY PACK (Attorney Docket No. 066042-9537-00), in co-pending U.S. patent application Ser. No. 11,138,070, filed May 24, 2005, entitled METHOD AND SYSTEM OF BATTERY PROTECTION (Attorney Docket No. 066042-9689-00), in co-pending U.S. patent application Ser. No. 11/165,615, filed Jun. 22, 2005, entitled BATTERY PACK (Attorney Docket No. 066042-9690-00), the entire contents of all of which are hereby incorporated by reference.  
         [0030]     In the illustrated constructions, the light  40  is configured to receive power from a battery  50  having a nominal voltage of approximately 28 V. In the illustrated constructions, the light  40  is also configured to receive power from a battery having a nominal voltage less than 28 V, such as, for example, approximately 12 V, approximately 14.4 V, approximately 18 V, approximately 21 V, and the like. In further constructions, the light  40  can receive power from a battery having a nominal voltage greater than 28 V.  
         [0031]     In the illustrated constructions, the light  40  includes a housing  60  supporting a circuit  70  (shown schematically in  FIGS. 18, 19  and  20 ). In some constructions, the circuit  70  includes a light source  75  and a switch  80  which couples the light source  75  to the power source, such as, for example, the battery  50 . The switch  80  is controlled by a user-activated on/off switch  85  supported by the housing  60 . In some constructions, the on/off switch  85  includes a first position for disabling the light source  75  and a second position for enabling the light source  75 . In other constructions, the on/off switch  85  can include more positions relating to various settings which control the brightness of the light source  85 . For example, the on/off switch  85  can include a first position for disabling the light source  75 , a second position for enabling the light source  75  in a high mode (e.g., full brightness), and a third position for enabling the light source  75  is a low mode (e.g., low brightness). In further constructions, the on/off switch  85  can include more positions than shown and described.  
         [0032]     The housing  60  includes a battery support portion  52 , a handle portion  54 , and a head portion  56 . The battery support portion  52  can physically support the battery  50  on the light  40  and on the housing  60 . The battery support portion  52  also includes a terminal assembly (not shown) for electrically connecting the battery  50  to the circuit  70 .  
         [0033]     The handle portion  54  supports the user-activated on/off switch  85 . As shown in  FIGS. 2, 6 ,  10  and  13 , the on/off switch  85  is positioned on the rear side  90  of the handle portion  54 . In other constructions, the on/off switch  85  can be located on another portion of the light  40 .  
         [0034]     The head portion  56  of the light  40  includes a light source receptacle (not shown) which couples the light source  75  to the control circuit  70 . The head portion  56  includes a removable cover  95  for providing access to the light source  75 . As shown in  FIG. 16 , the head portion  56  can pivot back and forth between a first position  96  and a second position  98 .  
         [0035]     One construction of the control circuit  70  is shown schematically in  FIG. 19 . As mentioned previously, the circuit  70  includes a light source  75 . In one construction, the light source  75  includes a removable 28 V light bulb. In other constructions, the light source  75  includes a removable light bulb having a different voltage rating. In further constructions, the light source  75  can include a light emitting diode. In still further constructions, the light source  75  can include multiple light sources, such as, for example, two or more light bulbs, two or more light emitting diodes, a combination of bulbs and diodes, or the like.  
         [0036]     As shown in  FIG. 19 , the circuit  70  includes a current shunt  110  that is positioned in series with the light source  75  and a semiconducting switch  120 . In the illustrated construction, the semiconducting switch  120  includes a field effect transistor (“FET”), such as, for example, a metal oxide semiconducting field effect transistor (“MOSFET”). The circuit  70  also includes an RC delay network  115 , a first comparator  120  and a duty-cycle control module  125 . The RC delay network  115  includes a first resistor  135  and a capacitor  140 . The duty-cycle control module  125  includes a second resistor  142  and the resistor  135  and the capacitor  140  of the RC delay network  115 .  
         [0037]     In the construction illustrated in  FIG. 19 , the circuit  70  can sense if an incorrect light bulb  75  has been inserted into the light source receptacle (not shown). For example, a user may insert a light bulb  75  having a lower voltage rating, such as, for example, a 12 V light bulb, a 14.4 V light bulb, an 18 V light bulb, or the like. When the circuit  70  senses an incorrect light source  75 , the circuit  70  can also perform one of two functions, depending on a few of the ratings of various components included in the circuit  70 .  
         [0038]     In a first construction, when the circuit  70  senses an incorrect light source  75  inserted in the light source receptacle, the circuit  70  will indicate to the user that an incorrect light source  75  is connected to the circuit  70 . For example, the circuit  70  can provide indication to the user by controlling the light source  75  (e.g., the light bulb) to flash on and off. In one example, the circuit  70  will flash the light source  75  on and off between approximately 0.5 cycles per second or approximately 1 cycle per second. According to this aspect, the light source  75  would be flashing on and off in such a manner that would render the light  40  useless for providing sufficient light to a user.  
         [0039]     In a second construction, when the circuit  70  senses an incorrect light source  75  inserted in the light source receptacle, the circuit  70  will limit the current being supplied to the light source  75 . The circuit  70  would limit the current in order to enable the light  40  to function with a lower-rated light source  75 . In the second construction, the circuit  70  limits the current supplied to the light source  75  by flashing the light source  75  on and off. However, in the second construction, the circuit  70  is controlling the light source to flash at a higher rate per second such that the flashing would not be readily apparent to a user. The duty-cycle control module  125  controls the output  150  of the comparator  120  in a hysteretic manner. The ratings of the first resistor  135 , the second resistor  142  and the capacitor  140  determine the upper and lower hysteretic threshold values of the comparator  120 .  
         [0040]     For both the first and second constructions, if a lower voltage bulb  75  is inserted in the light  40 , the filament resistance of the light source  75  will be lower. Thus, a light source  75  with a lower voltage rating will have a higher current rating. The voltage dropped across the current shunt  110  is fed into the RC delay network  115 . This voltage is in turn fed into the comparator  120  with a set point of reference. A lower voltage light source  75  will create a large voltage across the RC delay network  115  and once the reference voltage is tripped, the output  150  of the comparator  120  toggles. The toggled output  150  biases the semiconducting switch  112  back and forth between a conducting state and a non-conducting state. When the semiconducting switch  112  is biased into a non-conducting state, the capacitor  140  slowly discharges. The light source  75  remains off until the lower hysteretic value is reached. Once the comparator  120  resets, the light source  75  will turn on.  
         [0041]     As shown in  FIG. 19 , the circuit  70  can also include a low voltage monitor  205 . In some constructions, the low voltage monitor  205  can monitor the voltage of the battery  50  supplying power to the light  40  and can turn the light source  75  off at a first preset voltage level. Once the battery voltage drops below the first preset value, the light  40  will not be activated until the battery voltage rises above a second preset value. In some constructions, the first preset value is lower than the second preset value. In one construction, the low voltage monitor  205  can be reset when the on/off switch  80  is toggled off and back on. For example, the low voltage monitor  205  can set the first preset value to approximately 24 V and can set the second preset value to approximately 27 V. In other constructions, the low voltage monitor  205  can include higher or lower preset values than described above.  
         [0042]     As shown in  FIG. 19 , the low voltage monitor  205  includes a second comparator  210 . The comparator  210  is controlled using a preset point of reference defined by the ratings of a third resistor  215  and a fourth resistor  220 . A second capacitor  225  along with the fourth resistor  220  create a time delay network  230 . The time delay network  230  can ensure the battery voltage applied to the second comparator  210  at pin  240  has reached a steady state before the reference voltage applied to the second comparator  210  at pin  245  reaches a steady state value. The time delay network  230  can ensure no nuisance tripping of the low voltage battery monitor  205 .  
         [0043]     Still referring to  FIG. 19 , a logic AND gate  248  is formed by a first diode  250  and a second diode  255 . Once both comparator outputs are high then the semiconducting switch  112  is biased to a conducting state and the light source  75  will turn on. Similarly, if the output  260  of the second comparator  210  is low, the semiconducting switch  112  is biased to a non-conducting state and the light source  75  will turn off.  
         [0044]     Another construction of the circuit  70  is shown in  FIG. 20 . In the illustrated construction, the circuit  70  includes a “hold-up” capacitor  270  and a steering diode  275 . In some constructions, the battery  50  can include a microcontroller which may be programmed to periodically measure certain battery characteristics. In these constructions, the microcontroller briefly interrupts the discharge current for approximately 0.5 ms per second in order to obtain the measurements. If such a battery is supplying power to the light  40 , the hold-up capacitor  270  allows the circuit  70  to ignore the brief interruptions of discharge current which can cause the low voltage monitor  205  to trip during every interruption (causing the light source  205  to flash once every second). The steering diode  275  is positioned within the circuit  70  to prevent the light source  75  from pulling energy out of the hold-up capacitor  270  during the interruptions of discharge current.  
         [0045]     Still referring to  FIG. 20 , the circuit  70  can also include a sleep subcircuit to reduce parasitic current draw when the battery  50  is still electrically connected to the light  40 , but the light  40  is not turned on. The low voltage monitor  205  will shut off the light  40  when the battery reaches the first preset voltage threshold, such as, for example, approximately 26 V. When the battery voltage continues to fall and reaches a third voltage threshold, such as, for example, approximately 25.5 V, a zener diode  280  will begin to stop conducting. A first transistor  285  will stay conducting until the battery voltage reaches a fourth voltage threshold, such as, for example, approximately 25 V. Once the fourth voltage threshold is reaches, the zener diode  280  has stopped conducting completely and the first transistor  285  is cutoff. In one construction, for example, the control circuit  70  reduces the parasitic current from approximately 7 mA to approximately 0.1 uA.  
         [0046]     The constructions described above and illustrated in the figures are presented by way of example only and are not intended as a limitation upon the concepts and principles of the present invention.