Abstract:
A flashlight is provided with an end cap which carries an axially-actuated switch for turning the flashlight on and off with a convenient one-handed operation. The switch is designed with a latching function and a mode selection function which can be cycled through high, low and strobed light outputs with a partial throw of the switch. Cut-out portions are provided in the end cap for guiding a user&#39;s finger toward the switch and away from the sidewalls of the end cap.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of prior application Ser. No. 12/075,930 filed Mar. 14, 2008 entitled Compact Flashlight, now U.S. Pat. No. 7,604,371, and which is incorporated herein by reference in its entirety 
    
    
     BACKGROUND AND SUMMARY 
     High intensity flashlights are commonly carried by police and other law enforcement agents to aid in illuminating dark locations and to serve as a form of self defense. A bright intense light can temporarily stun or disorient an attacker when the light is directed at the attacker&#39;s eyes. Civilian versions of these flashlights are currently available in various shapes and sizes. 
     Many of the commercially-available self defense or tactical flashlights adapted for civilian use are intentionally large, bulky and heavy so that they can also be used as a club for striking in self defense. While these flashlights work well, they are not particularly well adapted for use by women and children who tend to prefer smaller and lighter flashlights. 
     Although some flashlights have been designed with reduced size and weight, they tend to overlook certain operating or human factors that are common to women. One factor overlooked is the long fingernails commonly worn by women. It has been found that long fingernails tend to interfere with the housings surrounding on-off switches of the type used in self defense and tactical flashlights. 
     This interference is a particular problem on flashlights having rear end-cap switches which are bordered or surrounded by a rim. When the switch is depressed in an axial or longitudinal direction, a long fingernail tends to abut or snag against any rim or other structure around the switch. This can prevent proper operation of the switch and result in a damaged fingernail. 
     Although some flashlight end cap switches project rearwardly and outwardly from the end cap, these exposed switches are easily activated unintentionally when bumped or dropped. This can unknowingly turn on the flashlight and drain the battery or batteries. 
     To overcome these problems, a compact flashlight has been designed with clearance for fingernails when operating and end cap switch, yet provides a guard around the end cap switch to prevent accidental actuation of the switch. The body and end cap of the flashlight are ergonomically designed for easy and comfortable one-handed operation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the Drawings 
         FIG. 1  is a rear perspective view of a first flashlight embodiment; 
         FIG. 2  is a side elevation view of  FIG. 1 , 
         FIG. 3  is a front perspective view of a second flashlight embodiment; 
         FIG. 4  is a partial rear perspective view of the end cap of  FIG. 3 , 
         FIG. 5  is a side elevation view of  FIG. 4 ; 
         FIG. 6  is a view of  FIG. 5  rotated 90 degrees and schematically showing the position of an operator&#39;s index finger; and 
         FIG. 7  is a central axial sectional view through a representative end cap of the type shown in  FIGS. 3-6 . 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     A flashlight  10  shown in  FIG. 1  includes a removable front crown  12  surrounding an axially-recessed lens covering a high intensity light-emitting-diode which provides an intense beam of light. The flashlight  10  further includes a tubular body  14  for housing one or more disposable or rechargeable batteries. A removable rear end cap  18  is threaded to the rear end of the tubular body  14 . 
     The end cap  18  includes a sidewall  20  that surrounds a user-operated switch actuator  22  which is operated by movement along flashlight axis  36 . As seen in  FIGS. 1 and 2 , the sidewall  20  is formed with three axially-rearweardly extending wall portions  24  which are symmetrically and circumferentially separated and spaced apart by three recesses, grooves or axial cut-out portions  28 . 
     The grooves  28  in  FIGS. 1 and 2  are formed as shallow U-shaped arcuate cuts or openings in the sidewall  20 . The edges  30  of each groove  28  are formed as sharp chisel edges for use in self defense. The top of each groove  28  meets a sharp corner point  32  at the corner of each flat end surface  34  at the rear axial end of the wall portions  24 . 
     The corner points  32  are useful for breaking glass, such as automobile window glass if needed to escape from inside a car or to free someone trapped inside a car. 
     As seen in  FIG. 2 , the switch actuator  22  is axially and radially recessed between and within the wall portions  24 . The flat end portions  34  of the wall portions  24  can extend axially from several millimeters to a centimeter or more beyond the top end surface of the switch actuator  22 . In this manner, the rearwardly-extending wall portions  24  protect the switch actuator  22  from unintended or accidental actuation, such as when the flashlight  10  is dropped or bumped. 
     The flat end surfaces  34  extend in a plane perpendicular to the longitudinally axis  36  of the flashlight  10  so that the flashlight  10  may be placed and remain upright on a flat surface in an on or off condition. This can free both of an operator&#39;s hands to work on overhead areas illuminated by the upright standing flashlight  10 . 
     The cut-out portions or grooves  28  provide free finger or thumb access through the sidewall  20  to axially depress the switch actuator  22  and thereby operate the flashlight  10  with one hand. While this arrangement works well for most users, some users with long fingernails can hit the sides or edges of the cut-out portions  28  or hit the flat end surfaces  34  with their fingernail. This can prevent full or adequate axial depression of switch actuator  22  and thereby prevent the desired operation of the flashlight  10 , i.e., turning the flashlight on or off or cycling the flashlight through other modes of operation such as high beam, low beam and high strobed beam. Moreover, such unwanted interference can cause split or damaged fingernails and chipped fingernail polish. 
     In order to further minimize or eliminate this condition, the flashlight  10  of  FIGS. 3-7  has been developed to provide free access to the switch actuator  22  while guiding a user&#39;s finger or thumb between a pair of opposed wall portions  24  and nesting the finger or thumb within a pair of diametrically opposed cut-out portions  28 . In this embodiment the wall portions  24  and cut-out portions  28  are diametrically and symmetrically opposed on opposite sides of end cap  18 . 
     As seen in  FIG. 5 , the end cap  18  can be formed with flat end surface portions  34  for placing the flashlight  10  upright on a flat horizontal surface. The side edges  40  of the cut-out portions  28  taper or converge axially forwardly and terminate at a flat horizontal floor portion  42  in sidewall  20 , or terminate at a curved floor portion as shown in  FIG. 4 . 
     The mouth or opening distance  44  between the corners  32  should be about 1.5 to 2.0 centimeters to comfortably accept a finger or thumb tip. The width  46  across the floor portion can be about 1.0 to 1.5 centimeters to nest one&#39;s finger or thumb comfortably in each cutout portion  28  and snugly against their side edges  40 . The tapered side edges  40  tend to center and guide one&#39;s finger or thumb onto the switch actuator  22 . 
     The switch actuator  22  can be recessed a distance  48  ( FIG. 5 ) below the flat surfaces  34  by two to six millimeters, preferably about three or four millimeters. The axial depth  50  of the cut out portions  28  can be about four to eight millimeters, preferably about four or five millimeters. The overall length of flashlight  10  can be anywhere from about 9 centimeters to about 15 centimeters or more with a diameter or width  52  of about 1.5 centimeters to 2.5 centimeters. These dimensions will provide a lightweight compact flashlight that can be easily operated with one hand. 
     As shown in  FIG. 6 , a user&#39;s index finger  54  can fully and easily depress the switch actuator  22  while maintaining a safe margin of clearance  56  with the floor  42  of recessed cut-out portion  28  of sidewall  20 . The user&#39;s long fingernail  60  is directed away from any portion of the sidewall  20  by the recesses  28  which direct the fingernail outwardly and away from the sidewall  20 , side edges  40  and floor  42 . 
     Details of a representative end cap assembly  63  are shown in  FIG. 7 . End cap  18  can be formed of an aluminum alloy, as can the remainder of the flashlight body  14  and front crown  12 . A threaded collar  62  is provided on end cap  18  for threaded removable engagement and electric continuity with the tubular body  14 . 
     The endcap assembly  63  includes a plastic insulating collar  64  which seats on a radial ledge  66  and receives a metal conical compression spring  68  which biases against and makes electrical contact with a battery housed within the tubular body  14 . A copper wave washer  70  seats on a second radial ledge  72  and makes electrical contact with the aluminum end cap  18 . 
     A circular circuit board  74  has conducting lands on its undersurface which make electrical contact with the spring  68  and with the end cap  18  through the wave washer  70 . The circuit board  74  can be provided with one or more integrated circuits or “chips” including micro logic circuits  78  that can control the operation of the flashlight  10  as discussed below. 
     A conventional button switch  80  includes a rectangular or box-shaped housing. A pair of electrical leads  82  extending outwardly from within the housing interconnect internal button switch terminals within the switch housing with circuits and control logic on circuit board  70 . A spring-biased plunger  84  completes contact between the electrical leads  82  when the plunger is axially depressed. 
     A plastic platform  86  seats on top of the button switch housing and provides a support surface for a dome-shaped resilient elastomeric diaphragm  88 . An externally-threaded washer  90  mates with an internal threaded portion of end cap  18  to clamp and hold the perimeter of diaphragm  88  in fixed axial position. The diaphragm  88  includes a movable plunger portion  92  which is coaxially aligned with the plunger  84  on the button switch  80 . 
     A light-activated luminescent material or a light-emitting material may be added to the elastomeric material of the diaphragm  88  to provide a “glow-in-the-dark” function. This facilitates locating and operating the diaphragm  88  in the dark. 
     When a user depresses the diaphragm  88 , the plunger  92  on the diaphragm depresses the plunger  84  on the button switch  80  and completes an electrical circuit across electrical leads  82 . This allows electrical current to flow through the circuits and logic components  78  on circuit board  74  via metal spring  68  which makes electrical contact with a land on the underside of circuit board  74 . The circuit is completed through the battery or batteries, through the LED&#39;s and through the body of the flashlight and wave washer  70  and back to the circuit board  74 . 
     Each time the button switch is pushed, the logic circuits  78  can be programmed to step the operation of the flashlight in virtually any desired sequence. For instance, the logic can operate as a simple alternating on-off switch which latches on or off each time the plunger  84  is fully depressed through a full axial throw. 
     Alternatively, the logic circuits  78  can be programmed to operate the flashlight in a sequence of high or bright light when the flashlight is first switched on, followed by a low or dull light when the plunger  84  is depressed again, and then off when the plunger is pressed a third time. In each case in this example, the functions of high, low and off are each maintained in a latched state until switched to the next function. 
     A rapidly pulsing or strobed lighting function can be easily provided to the function-switching sequences on either a high or low intensity setting by programming a timing and switching function in logic circuits  78 . In this case a user could select from high, high strobe, low or low strobe, each in a latched state. 
     Another option is to provide lighting functions with a conventional latched on and latched off function in combination with high, low and strobe light functions. This can be achieved by turning on the flashlight with a relatively long axial depression or axial throw of the plunger  84  to latch the flashlight on. Smaller or shorter axial depressions or axial throws of plunger  84  can provide pulses to the logic circuits  78  to scroll through any desired sequence of operations until the plunger is again fully depressed and latched off. 
     For example, with the flashlight off, a user can latch on the flashlight  10  in a high-intensity mode by strongly pressing the diaphragm  88  through its full range travel and releasing it. The high intensity light beam will stay on until the user either strongly depresses the diaphragm  88  through its full length of axial travel or until the user lightly depresses and releases the diaphragm through a short stroke or depression of diaphragm  88 . This short stroke and release will switch the light into a low intensity light beam output mode until the user fully and strongly depresses the diaphragm  88  again to turn the flashlight off, or again lightly depresses and releases the diaphragm  88  to switch to a strobe light output mode where the flashlight emits pulsed bursts of high intensity light beams. 
     The strobe mode will remain strobing until the operator fully depresses and releases the diaphragm  88  to turn off the flashlight or lightly depresses and releases the diaphragm  88  to cycle the function back to the high intensity light mode. In any mode of operation, the diaphragm  88  can be depressed and lightly held in a depressed condition without latching and thereby turn off the flashlight as long as the operator holds the diaphragm down. Upon releasing the diaphragm, the flashlight will return to its previous mode of operation. Alternatively, the circuit  78  will cycle the flashlight to a new mode of operation. 
     All of the above functions are conveniently provided by the microchip or control chip  78  in combination with the operation of the button switch. 
     There has been disclosed heretofore the best embodiment of the invention presently contemplated. However, it is to be understood that various changes and modifications may be made thereto without departing from the spirit of the invention.