Patent Publication Number: US-7581848-B1

Title: Flashlight with replaceable housing

Description:
FIELD OF THE INVENTION 
   The field of the invention relates to flashlights and more particularly to flashlights used by police or military personnel. 
   BACKGROUND OF THE INVENTION 
   Flashlights are generally known. Flashlights are generally constructed with a housing that holds a set of batteries. A switch and light source is typically located on an outer surface of the housing. The switch is connected in series with the light source and batteries. 
   Flashlights relied upon by the police and/or the military are used in different ways and have different requirements than flashlights used by civilians. For example, police or military personnel are often required to carry a great deal of equipment in order to achieve their assigned goals. Because of the equipment carried by police or military personnel, the size, weight and configuration of a flashlight is of critical importance. If a flashlight is bulky or heavy, then the flashlight may be left behind. If the office or military person is suddenly confronted by a threat in a darkened area, the absence of a flashlight could place the person&#39;s life in peril. 
   A flashlight carried by police or military personnel must also be reliable. In this regard, light sources (e.g., bulbs) that could easily burn out from use or are easily damaged from shock cannot be tolerated. In addition, the flashlight must provide a superior light output to weight ratio with a predictably long battery life. 
   Moreover, flashlights used by police or military personnel should not easily become weapons that can be used against the carrier. For this reason, a flashlight used by a police officer or military person should be compact and relatively small. However, even in keeping with the concept of small size, the flashlight should be adaptable to different battery configurations in order to accomplish different missions without loss of utility. Accordingly, a need exists for a flashlight that is small, yet adaptable, for the needs of police and military personnel. 
   SUMMARY 
   A flashlight is provided that includes a LED light source, a power circuit that provides power to the LED light source and a buck and boost power controller within the power circuit in series with the LED light source where the buck and boost circuit boosts a battery voltage to the light source when the battery voltage is below the predetermined voltage and reduces the battery voltage to the light source when the battery voltage exceeds the predetermined voltage. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a flashlight with a mode selector in accordance with an illustrated embodiment of the invention; 
       FIG. 2  shows the flashlight of  FIG. 1  with the mode selector in a third position; 
       FIGS. 2A-B  show operational details of a switch assembly of the flashlight of  FIG. 2  with the mode selector in the third position; 
       FIG. 3  shows the flashlight of  FIG. 1  with the mode selector in a first position; 
       FIGS. 3A-B  show operational details of the switch assembly of the flashlight of  FIG. 3  with the mode selector in the first position; 
       FIG. 4  shows the flashlight of  FIG. 1  with the mode selector in a second position; 
       FIGS. 4A-B  show operational details of a switch assembly of the flashlight of  FIG. 4  with the mode selector in the second position; 
       FIG. 5  is an exploded view of the flashlight of  FIG. 1 ; 
       FIG. 6  is a cut-away view of the flashlight of  FIG. 1  shown with two batteries; 
       FIG. 7  is a cut-away view of the flashlight of  FIG. 1  under an alternate embodiment wherein the housing of the flashlight of  FIG. 1  contains three batteries; 
       FIG. 8  is a cut-away view of the flashlight of  FIG. 1  under another alternate embodiment wherein the housing of the flashlight of  FIG. 1  contains four batteries; 
       FIG. 9  shows the flashlight of  FIG. 1  being held by a user in a non-threat hand; and 
       FIG. 10  shows the flashlight of  FIG. 1  being held by a user in a threat hand with a weapon in the other hand. 
   

   DETAILED DESCRIPTION OF AN ILLUSTRATED EMBODIMENT 
     FIG. 1  is a side view of a flashlight  10  shown generally in accordance with an illustrated embodiment of the invention. The flashlight  10  includes a housing  12 , a light source assembly  16  on a first end of the flashlight  10  and a switch control assembly  14  on a second end of the flashlight  10 . 
   The switch control assembly  14  is provided with a rotatable cap (i.e., a mode selector)  18  extending axially from the second end of the housing. The mode selector  18  rotates around a predominant axis  19  of the housing  12 . 
   A spring-loaded pushbutton  20  extends axially from a distal end of the mode selector cap  18  ( FIG. 2 ). As used herein, a spring-loaded pushbutton is a pushbutton that must be activated by an external force (e.g., the finger of a user) and that returns to the same deactivated state each time the external force is removed. 
   The mode selector cap  18  has a first position of rotation wherein the light source cannot be activated. The position wherein the light source cannot be activated is shown in  FIG. 3  wherein the short horizontal line  11  on the mode selector  18  is aligned with the short horizontal line  13  on the housing  12 . 
   The mode selection cap  18  also has a second position of rotation wherein the light source activates only for so long as the pushbutton  20  is activated. The second position is shown in  FIG. 4  and is defined by alignment between the line  11  and open circle  15 . 
   The mode selector cap  18  also has a third position of rotation wherein the light source transitions from an OFF to an ON state or from an ON to an OFF state once each time the pushbutton  20  is activated. The third position is shown in  FIG. 2  and is defined by alignment between the line  11  and closed circle  17 . 
   The flashlight  10  is constructed so that when the flashlight is held in a palm of a user&#39;s left hand, the second position can be achieved by grasping the mode selection cap between the user&#39;s thumb and forefinger and pushing with the thumb while pulling with the forefinger. Alternatively, when the flashlight is held in a palm of a user&#39;s right hand, the first position can be achieved by grasping the mode selection cap between the user&#39;s thumb and forefinger and pushing with the thumb while pulling with the forefinger. 
   This arrangement is a safety feature for a police officer who preferentially uses one hand (e.g., a right hand) for a weapon (e.g., a firearm). This arrangement is a safety feature because if the police officer is holding a gun in his right hand and the flashlight  10  in his left hand as shown in  FIG. 10 , then the officer would not want to activate the flashlight  10  in a mode where the flashlight  10  remains activated after the pushbutton  20  is released. Under this naming convention, the officer&#39;s left hand is referred to as the “threat hand” for holding the flashlight  10  and the right hand is referred to as the “safe hand” for holding the flashlight  10 . This terminology is used because if the officer is holding the flashlight  10  in his/her right hand (i.e. the safe hand) as shown in  FIG. 9 , then the officer does not feel threatened and would want the flashlight  10  to remain activated after the first activation of the pushbutton  20 . On the other hand, if the officer is holding the flashlight in his/her “threat hand”, then the officer feels threatened and may or may not have his gun drawn in his right hand. In the situation where the officer feels threatened, the officer will use a mode of flashlight use called “flicking.” In this case, the officer will flick the pushbutton  20  of the flashlight to momentarily illuminate a target. The short time of activation allows the officer to view a target without leaving himself/herself exposed to weapons fire. 
   It should be noted that while the flashlight  10  is intended for a right-handed officer, a left-handed officer could also use the flashlight  10 . In the case of the left-handed officer, the officer would have to be trained to pull with his thumb and push with his/her forefinger. The naming convention of threat and safe hand would also be reversed. 
   Turning to  FIG. 6 , the switch control assembly  14  will be discussed first.  FIG. 6  is a cut-away view of the flashlight  10 . As shown in  FIG. 6 , an axially extending rib  22  on a side of the pushbutton  20  and complementary slot  24  on an inside surface of the mode selector cap  18  allows the pushbutton  20  to be pushed towards the flashlight in a direction parallel to the predominant axis  19  against the force of a spring  27  when a user activates a proximal end of the pushbutton  20  with his finger. Since the rib  22  and slot  24  are parallel to the predominant axis  19 , the pushbutton  20  can easily be pushed inward by the user&#39;s thumb without moving the mode selector  18  and wherein the spring  27  will return the pushbutton  20  to a deactivated state when the pushbutton  20  is released. However, when the mode selector  18  is rotated, the rib  22  and complementary slot  24  also causes the pushbutton  20  to rotate in unison with the mode selector  18 . 
   A distal end of the pushbutton  20  (i.e., inside the flashlight  10 ) is provided with an inside aperture  29  that extends over a switch assembly  30  ( FIG. 5 ) and allows a pin  26  on an inside of the pushbutton  20  to activate a switch  28  of the switch assembly  30  when the mode selector  18  is in its second and third positions. 
   In this regard, the distal end of the pushbutton  20  has an inside diameter that is slightly larger than an outside diameter of the switch assembly  30 . One or more axially extending ribs  32  ( FIG. 3 ) on the outside surface of the switch assembly  30  engages a set of complementary slots  34  on an inside surface of the pushbutton  20 . 
   The ribs  32  and slots  34  prevent relative axial movement of the pushbutton  20  and switch assembly  30  unless the mode selector  18  is in one of the first, second or third positions. As noted above, the mode selector  18  and pushbutton  20  must rotate together because of the rib  22  on the outside of the pushbutton  20  and slot  24  on the outside of the mode selector  18  and therefore the rotational position of the mode selector  18  also defines the rotational position of the pushbutton  20 . 
   A projection  38  on a switch assembly  30  ( FIG. 3A ) engages a switch control profile  36  that extends around the periphery of the distal end of the pushbutton  20 . In the first, second and third positions of the mode selector  18 , a different portion of the profile  36  of the pushbutton  20  bottoms out against the projection  38  when the pushbutton  20  is activated by a user. 
     FIG. 3A  shows the pushbutton  20  and switch assembly  30  with the mode selector in the first position and with the pushbutton  20  in an activated state.  FIG. 3B  shows the pushbutton  20  and switch assembly  30  with the mode selector in the first position and with the pushbutton  20  in a deactivated state. 
   In the first position of the mode selector  18 , the projection  38  engages a first portion  40  of the control profile  36  ( FIG. 3A ). The first portion  40  is an extended portion of the tubular body of the pushbutton  20  that allows only a limited movement of the pushbutton  20  into the housing  12 . The limited movement of the pushbutton  20  prevents the pin  26  from contacting the switch  28 . 
     FIG. 4A  shows the pushbutton  20  and switch assembly  30  with the mode selector in the second position and with the pushbutton  20  in an activated state.  FIG. 4B  shows the pushbutton  20  and switch assembly  30  with the mode selector in the second position and with the pushbutton  20  in a deactivated state. 
   When the mode selector cap  18  is rotated to the second position ( FIG. 4 ), the projection  38  contacts a second portion  42  of the control profile  36  ( FIG. 4B ). The second portion  42  allows the pushbutton  20  to be advanced into the housing  12  to a second position that is further into the flashlight  10 . In the second position, the pin  26  engages the switch  28  to move an activation pin of the switch  28  a first distance. 
   The switch  28  is a wiping contact type switch with two modes of operation. If the switch is moved the first distance, the switch  28  operates as a momentary contact switch  28 . If the switch is moved any further, then the switch  28  operates as a toggle switch that maintains the switch status (i.e., open or closed) until it is again toggled. 
   With the mode selector  18  in the second position, the switch  28  operates as a momentary contact switch. As such, when the user activates the pushbutton  20 , the switch  28  completes the circuit and activates the flashlight  10 . When the user releases the pushbutton  20 , the flashlight  10  automatically becomes deactivated. 
     FIG. 2A  shows the pushbutton  20  and switch assembly  30  with the mode selector in the third position and with the pushbutton  20  in an activated state.  FIG. 2B  shows the pushbutton  20  and switch assembly  30  with the mode selector in the third position and with the pushbutton  20  in a deactivated state. 
   When the user moves the mode selector  18  into the third position ( FIG. 2 ), the portion  44  contacts the projection  38  ( FIG. 2B ). In this mode, the pin  26  encounters and advances the activation pin of the switch  28  sufficiently to toggle the switch  28 . In this situation, the flashlight  10  remains activated when the user releases the pushbutton  20 . To deactivate the flashlight  10 , the user must activate the pushbutton  20  a second time. 
   The light source assembly  16  will now be discussed. Returning now to  FIG. 5 , the light source assembly  16  contains a power control circuit board  50  and a light emitting diode (LED) circuit board  52 . The power control board  50  and LED circuit board  52  are orthogonal to the predominant axis  19 . The power control board  50  and LED circuit board  52  are detachably interconnected via a set of push-on electrical connectors  58 ,  60 . One set of male connectors (e.g., connector set  58 ) is attached (e.g., soldered) to one circuit board (e.g., the LED circuit board  52 ) and the other set of female connectors (e.g., connector set  60 ) is attached (e.g., soldered) to the other circuit board (e.g., the power control board  50 . As such, the power circuit board  50  and LED circuit board  52  shown in  FIG. 5  can easily be pulled apart and reconnected via the push-on connectors  58 ,  60 . 
   Included on the LED circuit board  52  may by one or more LEDs  54  and associated reflectors  56  ( FIGS. 5 and 7 ). In one preferred embodiment, three LEDs  54  are used. The LEDs  54  may be connected in series between respective connectors  58  on the LED board  52  to equalize the current among the LEDs  54 . A ten volt potential may be applied across the series connected LEDs  54 . 
   The reflectors  56  provide a peripheral flood beam and a central penetrating beam that projects a strong central beam for a relatively long distance. The peripheral flood beam projects light at a predetermined light level (e.g.,  5  lumens) over a relatively wide angle (e.g., 90 degrees) from the predetermined axis of light transmission from the flashlight so that a user can at least minimally observe obstacles and threats off the main axis of the flashlight. The penetrating beam is directed at a relatively small axis (e.g., a few degrees) from the predominant axis of the flashlight so that a user can identify any danger at relatively long distances presented by a person with a weapon. The peripheral flood beam and strong central beam is created by the appropriate parabolic shape of the reflector  56  and also by the alignment of the reflectors  56  with respect to the predominant axis of the flashlight. 
   The power control board  50  may include a number of integrated circuits  62 ,  64  that function as a buck and boost circuit. It should be noted in this regard that the flashlight  10  may be provided with a number of different housings  12  shown in  FIGS. 6 ,  7  and  8 . One housing  12  may be provided with a length that contains two 3-volt lithium batteries ( FIG. 6 ). Another housing  12  may be provided that holds three 3-volt lithium batteries ( FIG. 7 ). A third housing may be provided that holds four 3-volt lithium batteries ( FIG. 8 ). 
   At least one of the integrated circuits (e.g., circuit  62 ) may be a voltage sensor and the other circuit (e.g.,  64 ) is a buck and boost circuit  64 . The voltage sensor  62  functions to detect the voltage of the batteries within a battery compartment  64  and either buck or boost the battery voltage to provide a constant 10-volt potential to the LEDs  54 . For example, if the housing  12  contains only two 3-volt batteries, then the voltage sensor  62  will detect that the battery voltage is 6 volts. In this case, the voltage sensor  62  may instruct the buck and boost circuit  64  to boost the battery voltage by 4 volts in order to apply 10 volts to the series connected LEDs  54 . Similarly, if the housing  12  contains four batteries then the voltage sensor  62  may detect a battery voltage of 12-volts and would instruct the buck and boost circuit  64  to reduce the battery voltage to 10-volts. 
   The buck and boost circuit  64  provides a number of benefits. On a first level, the reduction of voltage applied to the LEDs  54  extends a useful life of the batteries. 
   In addition, the buck and boost circuit  64  also prevents damage to the LEDs  54  due to overheating. In order to achieve a good light output, the voltage applied to the LEDs  54  may be as much as 140% of a rated voltage for the LEDs  54 . However, the fact that the buck and boost circuit  64  maintains the voltage at a constant level allows the LEDs  54  to be powered at a relatively high voltage without a significant reduction in LED life. 
   The buck and boost circuit  64  also maintains a comfort level for a user. In this regard, the buck and boost circuit  64  controls the heat generated within the LEDs  54  so that a temperature of the outside surface of the flashlight is less than 140° F. This prevents the case of the flashlight from becoming overly warm or burning the hands of a user. 
   The use of a replaceable housing  12  that may contain different numbers of batteries allows the flashlight  10  to be instantly reconfigured for different uses. If the user has a relatively short mission, then the shorter housing (shown in  FIG. 6  containing only two batteries) would be used. If the mission is longer, then a longer housing  12  (e.g., as shown in  FIG. 7  or  8 ) would be used to extend the useful life of the flashlight  10  in any particular mission. 
   In addition, the bi-directional nature of a mode selector  18  increases the safety of the user. In each case, the first or third modes (selected via the mode selector  18 ) of the flashlight  10  is determined by the hand in which the flashlight  10  is held. This method of operation materially improves the safety of the user because the user simply selects the mode using the same mechanical operation of pushing with his/her thumb and pulling with his forefinger rather than forcing the user to consciously think of which mode is being selected. 
   Moreover, the flashlight  10  can be easily repaired in the event of failure. For example, if the LED circuit board  52  should fail, a user may simply unscrew a lenscap  66  and pull the LED circuit board  52  out through the face of the flashlight  10  without tools. A replacement LED circuit board  52  may be installed by reversing the process. 
   Similarly, the power circuit board  50  may be removed and replaced by unscrewing a front cap  70  and removing a snap ring  68  to access the power circuit board  50 . The switch assembly  30  may be replaced by a similar process involving unscrewing a switch case cap  72  and removing another snap ring  74 . 
   Further, it will be understood that the flashlights of the present invention can be modified without departing from the teachings of the invention. Accordingly, the scope of the invention is only to be limited as necessitated by the accompanying claims.