Abstract:
The flashlight of the present invention is comprised generally of a flashlight chassis which houses energy cells, a flashlight head which houses a beam adjustment assembly, and an endcap which houses a switch assembly. The beam adjustment assembly and the switch assembly utilize printed circuit boards to support the lamp bulb and switch, respectively. The beam adjustment assembly mounts inside the flashlight head and can only be accessed and adjusted by removing the outer lens retaining ring that secures the assembly within the head. Once accessed, the bulb support of the assembly can be rotated relative to the reflector of the assembly to adjust the light focal length of the flashlight. The adjustment assembly is also provided with a shock absorber that supports the light bulb. In one embodiment, the endcap is provided with a threads to permit the flashlight to be axially attached to an expandable baton. This embodiment also incorporates a side mounted switch to enhance manipulation and use of the combination flashlight/expandable baton device. In another embodiment, the endcap has an end-mounted switch to permit full extension of the flashlight. In each embodiment, a multi-function, low noise, push-button switch is utilized. The switch mounts on the printed circuit board, and is provided with primary and secondary circuits to guard against switch failure. The switch is protected by a cover integrally formed of an o-ring.

Description:
BACKGROUND OF INVENTION 
     1. Field of Invention 
     This invention is generally related to flashlights and is more specifically directed to flashlights that can be attached to implements such as law enforcement batons or nightsticks. The invention is most specifically directed to a flashlight that incorporates circuit boards as electrical components, an adjustable focus that cannot be inadvertently altered, and a switch that is positioned to enhance ease of use particularly in law enforcement situations. 
     2. Description of the Prior Art 
     Flashlights are well known in the prior art and have been heavily utilized in emergency situations and by law enforcement personnel in the execution of their duties. During use, such flashlights may be subjected to harsh environments and treatment, and therefore should be designed to withstand the application of various forces, whether rolling around under the seat of a car or blocking blows from suspects, as well as the presence of debris, including water and mud, that could interfere with the operation of the flashlight. Generally, such flashlights include a housing which is formed of a body section and a head section. The head section typically is disposed to receive a lens, a reflector, and a lamp, all of which are secured in the head by a lens ring that is threadingly engaged with the head section. The body section houses batteries utilized to energize the lamp. 
     The electrical circuit of such flashlights is typically comprised of a first wire or metallic strip that connects the positive terminal of the battery with the positive lead of the lamp, and a second wire or metallic strip that connects the negative terminal of the battery with the negative lead of the lamp. The second wire may be attached to an electrically conductive spring that contacts the negative terminal of the battery while urging the positive terminal of the battery into contact with the first wire. In some prior art embodiments, the second wire is attached directly to the flashlight housing or barrel such that the circuit is completed utilizing the housing itself as a conductor, the housing also being attached to the conductive spring. 
     To control operation of the lamp, a switch is disposed within the circuit. There are numerous varieties of switches that are utilized in the prior art to open and close a circuit. These switches are generally either mechanical or electrical. One common variety is a slide switch that mounts on the forward body section of the flashlight and utilizes a metallic strip to bridge a gap created in the wiring on the negative side of the electrical system. The switch includes a slide member that mounts in a slot on the external surface of the body section. The slide member can be used to move the metallic strip between a first “off” position in which the metallic strip is insulated from contact with the negative side of the electrical system and a second “on” position in which the metallic strip bridges the gap in the circuit, closing the circuit to activate the flashlight lamp. 
     Another type of switch simply replaces the slide switch with a forward mounted, push-button switch that can be activated to open and close a circuit. Push-button switches, whether mechanical or electrical, are well known in the art and are generally characterized by a distinctive “click” as the switch is engaged and disengaged. In the case of mechanical push-button switches, this “click” is generated as metallic parts within the switch strike one another. In other instances, such as in electrical pushbutton switches, the “click” emanates from the depression and release of a spring mechanism or catch mechanism within the switch. In any event, such switches are undesirable because the distinctive “click” could be used by suspects or those under surveillance to identify the presence or location of law enforcement personnel. 
     Push button switches are also commonly used as “dead man” switches. In law enforcement, it is often desirable to utilize a switch that only maintains electrical contact when the switch is depressed and manually held down by the user. Upon release of the button, the electrical circuit is interrupted. Thus if the flashlight falls from the user&#39;s hand, the circuit is broken and the flashlight is extinguished. For example, if a police officer becomes injured or incapacitated in such a way as to drop his or her flashlight, a deadman switch will cause the flashlight to extinguish, preventing a suspect from ascertaining the injured officer&#39;s location. Another common use of such a switch is to permit intermittent use of a flashlight, such as for signalling purposes. In any event, like the other prior art push button-type switches, dead man switches are characterized by a distinctive “click” as the switch is engaged and disengaged. 
     Although push button switches are generally more reliable than slide switches, push button switches are susceptible to damage from exposure to moisture or particulate matter such as dust or dirt. Therefore, push button switches incorporated into flashlights are often covered to inhibit migration of moisture and debris into the switch. The covering is usually some type of thin, resilient membrane such as rubber or the like and may take several different forms. For example, MAGLITE, a well known flashlight manufacturer, provides a bowl shaped cover with a thin lip around the open end of the cover. The cover also has an aperture or slit in the center of the bowl. To “seal” the cover over the switch, the cover is placed over the switch so that the lip is sandwiched between an inner portion and an outer portion of the flashlight. An allen wrench is then inserted through the slit to engage a threaded fastener attaching the inner and outer portions. The threaded fastener is then rotated to draw the inner and outer portions together such that the lip of the switch cover is tightly sandwiched between the inner and outer portions. Clearly, although the outer perimeter of the switch cover is sealed, the slit in the bowl of the switch cover still renders the switch cover penetrable by moisture and debris. 
     Another type of switch used in the prior art flashlights utilizes the flashlight housing as a portion of the negative side of the electrical circuit. Typically, these types of flashlights require rotation of one portion of the flashlight body relative to another portion of the flashlight body to open and close the circuit. The head of the flashlight must be rotated relative to the body of the flashlight to activate and deactivate the flashlight lamp. In such a configuration, the negative lead from the lamp is attached to the flashlight head, while the negative terminal from the battery is attached to the flashlight body. The body and the head are threadingly engaged to permit rotation of the head relative to the body. When assembled, the head and body are insulated from one another to preclude electrical contact. Only upon additional rotation of the head towards the body is electrical contact between conductive portions of the two sections achieved such that the negative circuit is closed. 
     In another similar type of switch, a flashlight is provided with an endcap that can be rotated relative to the body of the flashlight to close the negative side of the electrical circuit. The endcap is in electrical contact with the negative terminal of a battery and is threadingly engaged with the flashlight body. However, the endcap is insulated from electrical contact with the body itself such that the conductive portions of the body and endcap are not in contact. Only upon rotation of the endcap relative to the body are the electrically conductive portions of the endcap and body brought together to close the circuit and activate the flashlight lamp. An example of such a flashlight is manufactured by Laser Products, and further includes a mechanical deadman switch positioned on side of the endcap. 
     Switches such as the above-mentioned push-button type and slide type are typically mounted at the forward end of the flashlight near the head portion of the body. More specifically, such switches at or forward of the center of gravity of the flashlight because the most common activation finger, the thumb, naturally rests at this point. Flashlights are most often supported in the “underhand” position by resting the barrel of the flashlight on the fingers and closing the palm of the hand around the side of the barrel such that the thumb is disposed on the top of the barrel and points forward, away from the user. This position enhances the balance of the flashlight in the fingers and palm of a user&#39;s hand while permitting the user to easily activate and deactivate the switch with the forward pointed thumb. With such a grip, the “ready” position of the light is comfortably between the waist and chest. 
     Law enforcement personnel more commonly support flashlights in the “overhand” position that permits the light to be most comfortably held at shoulder level or higher. Specifically, this position entails resting the barrel of the flashlight in the palm of the hand and closing the fingers around the side and over the top of the barrel. In this position, the thumb is disposed on the bottom of the barrel and points backward, toward the user. With the thumb in this position, a forward mounted switch would be difficult to operate. Therefore, placement of the prior art switches is not conducive to use by law enforcement personnel who are often required to hold the flashlight in a specific “maneuver” position or in combination with other instruments. 
     One common problem with the push-button type and slide type switches of the prior art is that they are not typically provided with a “back-up” system or method for ensuring that the flashlight will continue to function should a portion of the switch fail. For example, it is typical for the metallic strip of the slide type switch to become loose over time, unintentionally interrupting the electrical contact between the metallic strip and the wires of the circuit. The result of such an interruption is failure of circuit and hence failure of the flashlight. Failure of the flashlight, especially in emergency or law enforcement situations, is undesirable at best and could place the flashlight user in jeopardy. 
     Notwithstanding the manner is which prior art flashlights are activated, such flashlights are typically pre-focused at the factory to provide a light beam that is a combination of a spot light and a flood light. Spot lights are characterized by a narrow, intense beam of light that projects over a distance, while flood lights are characterized by a broad, diffused beam of light that illuminates the immediate area around the light. The nature of a particular beam of light is determined by the light focal length (LFL), which is the distance between the light bulb filament and the base of the parabolic reflector. The greater the LFL, the more diffused the light beam. In other words, a flood light has a larger LFL than a spot light. 
     In any event, most prior art flashlights are pre-set at the factory to have a light beam that is a combination flood and spot. The position of the light bulb relative to the reflector is permanently fixed at the factory to achieve this combination. One problem with such flashlights is that the position of the filament from light bulb to light bulb is not exact. Thus the LFL for a flashlight can vary depending on the particular light bulb inserted into the flashlight. 
     More recent prior art flashlights have been focusable. Focusable flashlights permit the user to select the type of beam to be generated—either flood, spot or a combination—depending on the user&#39;s particular requirements. Focusable flashlights are typically adjusted by turning the head of the flashlight relative to the body of the flashlight. The reflector is attached to the head of the flashlight while the light bulb is attached to the body of the flashlight. Since the head of the flashlight is threadingly attached to the body of the flashlight, rotation of the head of the flashlight relative to the body alters the LFL, permitting a user to achieve the desired beam of light. One drawback to a focusable flashlight is that the relative position of the body and the head of the flashlight can be altered inadvertently, especially when the threads attaching the head to the body become worn or loose. 
     Flashlights used in law enforcement or emergency situations are often subject to harsh environments and treatment. A blow to the outside of a focusable prior art flashlight has a tendency to knock the flashlight out of focus. The same is true for flashlights that may be left to roll around in a vehicle—the head of the flashlight may have a tendency to move relative to the body of the flashlight. Clearly, there are many instances in which a flashlight focusable by rotating the head relative to the body can be inadvertently altered. In such instances, the focus of the flashlight must be re-set each time the flashlight is used, consuming valuable time and frustrating to the user. 
     Another drawback to prior art flashlights, especially those subject to harsh treatment, is that the flashlights may not sufficiently insulate the lamp bulb from external shocks placed on the flashlight. Flashlight bulbs are generally provided with a positive and negative pin extending from the end of the lamp bulb. In prior art flashlights, typically, the bulb is cantilevered on the two conducting pins of the lamp bulb such that the glass end, the most fragile portion of a lamp bulb, is unsupported. External blows placed on the flashlight or sudden movements of the flashlight can result in damage to an unsupported lamp bulb. This is especially true since the cantilevered nature of the prior art lamp bulbs has a tendency to magnify forces transferred to the glass body of the bulb through the attachment pins. 
     Based on the prior art flashlights, therefore, it would be desirable to provide a law enforcement flashlight that is reliable while being suited to withstand the rigorous treatment and environments common to law enforcement. As such, not only should the electrical circuit be reliable, but the lamp bulb and lamp switch should be protected from damage as well. In addition, the focus of the flashlight should be adjustable and adaptable to suit the particular situation in which it is utilized, yet should remain tightly focused even when the flashlight is subjected to external forces. The flashlight should be comfortable to hold and easily operable, yet should be configured to minimize revealing the presence or location of the user. Finally, the flashlight should also be adaptable for use with other law enforcement tools, such as an ASP expandable baton. 
     SUMMARY OF THE INVENTION 
     Flashlights are often utilized by law enforcement personnel in the execution of their duties. Typically, law enforcement personnel rely on several different instruments in performing these duties. The most notable of these instruments are a firearm, an expandable baton or nightstick, a flashlight, and handcuffs. Although each may be necessary in any given situation, the officer is limited to the number of instruments he or she can safely hold and manipulate at one time. For example, it would be awkward to handle a firearm, a flashlight and an expandable baton all at one time. An officer might be forced to select only two based on his or her best guess of an unknown situation. It would be much more desirable if the officer could have all three items drawn without the need to select between the three. 
     The subject invention is specifically directed to a flashlight adapted for use by law enforcement personnel. The flashlight includes a rear mounted switch housing that permits operation of the flashlight in the “overhanded” position. The switch may be placed on the outer end of the switch housing or on the side of the switch housing. In either position, the switch is easily activated by the thumb. When provided with a side mounted switch, the flashlight is ideally suited to be attached directly to another law enforcement implement, such as, by way of example, an expandable baton. The lamp assembly of the flashlight provides for adjustment of the light focal length, whereby a precise focus may be maintained. The flashlight assembly includes shock absorbing characteristics to prevent potential malfunction during rigorous use, and is well-sealed to provide good protection against migration of moisture and debris into the functional components of the flashlight. The switch assembly is a silent action push button with a redundant circuit to further safeguard against malfunction. The flashlight assembly of the preferred embodiment incorporates a unique circuit board configuration for positively mounting both the lamp and the switch to provide for better electrical contact. 
     More specifically, the flashlight of the subject invention provides a circuit that is less likely to be damaged through shock applied to the exterior of the flashlight by incorporating printed circuit boards throughout the flashlight. In addition, the switches incorporated into the flashlight are less likely to be subject to wear than prior art flashlights. Furthermore, the primary switch circuit is provided with an auxiliary circuits in the event of failure of the primary switch circuit. Because the switches are disposed for use with circuit boards as internal electronic components, they operate more quietly than prior art flashlight switches. The flashlight is also provided with a beam adjustment assembly that permits adjustment of the light beam but prevents inadvertent displacement of the lamp bulb relative to the reflector. The beam adjustment assembly further incorporates a shock absorber to prevent damage to the lamp bulb. Finally, the flashlight is adaptable for attachment to expandable batons. 
     The flashlight of the current invention is comprised generally of a flashlight barrel which houses energy cells, a flashlight head which houses a beam adjustment assembly, and an endcap housing for a switch assembly. The beam adjustment assembly and the switch assembly utilize printed circuit boards to support the lamp bulb and switch, respectively, and provide positive electrical contact between the energy cells and the conductive elements of the flashlight barrel, head and endcap housing. 
     Specifically, a first circuit board is incorporated in the beam adjustment assembly and a second circuit board is incorporated in the switch assembly. The lamp is attached directly to the first circuit board which is in contact with the positive terminal of the energy cells via a circuit board retaining ring, i.e., the positive terminal of the energy cell bears against the circuit board retaining ring. A push-button switch is attached directly to the second circuit board which is in contact with the negative terminal of the energy cells via a spring which is attached to the second circuit board and bears against the negative terminal of the energy cells. The flashlight barrel is utilized to complete the circuit by providing electrical contact between the first and second circuit boards. 
     The switch utilized in the circuit is of the pushbutton type, yet is designed to have a virtually silent operation. The switch is provided with pins to permit attachment to a printed circuit board. The switch is also provided with a “dead man” feature, as well as primary and secondary circuits to ensure uninterrupted operation of the flashlight circuit. Finally, the switch is sealed in the flashlight chassis utilizing a unique switch cover that is integrally formed of a bowl shaped section and an o-ring. 
     The beam adjustment assembly is used to adjust the LFL by moving the lamp relative to the fixed position of a reflector. The beam adjustment assembly is generally comprised of a parabolic reflector, a lamp support base which is threadingly engaged to the reflector, and a lamp attached to the support base. Since the support base is threadingly engaged to the reflector, the position of the support base, and hence the lamp, relative to the reflector can be altered by rotation of the base at the point of attachment to the reflector. To insure that the position of the lamp and reflector relative to one another is precisely maintained during use of the flashlight, the beam adjustment assembly is secured within the head of the flashlight such that the beam can only be adjusted by partial disassembly of the flashlight head. Specifically, the beam adjustment assembly, including the reflector are secured within the head of the flashlight by the lens ring. Upon removal of the lens ring and lens, the beam adjustment assembly can be removed to permit rotation of the lamp support base relative to the reflector. Once the desired LFL is achieved, the beam adjustment assembly is replaced in the head of the flashlight and secured in place by the lens retainer ring. 
     Another important feature of the flashlight of the invention is that the flashlight is adapted to attach to expandable batons. An expandable baton is generally comprised of a handle section in which is mounted multiple, nested extension sections of decreasing diameter. An internally threaded endcap and a retaining clip are used to secure the nested sections within the handle of the baton. Upon radial rotation of the handle section, the nested sections deploy such that the end of first section seats in the end of a second adjacent section in which the first section is nested. A sharp axial force applied to the outermost baton section is required to collapse such a baton. 
     As mentioned above, the flashlight of the invention includes an endcap which houses the switch assembly. In one embodiment, the proximal portion of the flashlight endcap is attached to the flashlight chassis while the distal portion of the endcap is provided with an open, internally threaded bore. The flashlight endcap is also provided with a dividing wall that separates the distal portion of the endcap from the proximal portion of the endcap. This configuration permits the flashlight endcap to be attached to an expandable baton in place of the standard baton endcap, such that the flashlight and the baton are coaxial. When so configured, a law enforcement officer is provided with a flashlight and an expandable baton in a single instrument. 
     Another important feature of the flashlight of the invention is rear, side mounted switch on the body of the flashlight. Most prior art flashlights locate the switch, whether a push-button or slide-type, on the side of the flashlight near the head of the flashlight, i.e., at the flashlight&#39;s approximate center of gravity. None of the prior art flashlights provide a rear, side mounted switch that is an electrical, push-button switch with multiple functions. As mentioned above, one feature of the invention is to allow attachment to an expandable baton. When attached to an expandable baton, the center of gravity of the flashlight shifts along the axis of the flashlight toward the baton. Thus, where a prior art flashlight with a forward mounted switch balances comfortably in a user&#39;s hand to permit easy manipulation of the switch, that same flashlight would be end heavy when attached to an expandable baton. As a result, the combination of a prior art flashlight with an expandable baton would be difficult to manipulate and would not be comfortably balanced in a user&#39;s hand. By providing a rear, side mounted switch, the flashlight of the invention is better disposed for use with expandable batons. 
     In another embodiment, the flashlight of the invention is provided with an endcap having a rear mounted switch. Such a switch permits full extension of the flashlight during use. To enhance ease of manufacture, as well as versatility, the internal components of the endcap having an end mounted switch are interchangeable with the internal components of endcap having a side mounted switch. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cut-away side view of the flashlight of the invention with a endcap having a side mounted switch assembly. 
     FIG. 2A is a perspective of the flashlight of FIG.  1 . 
     FIG. 2B is an exploded perspective view of the flashlight of FIG.  2 A. 
     FIG. 2C is a partially exploded perspective view of the end cap assembly of FIG.  1 . 
     FIG. 2D is an exploded perspective view of the bulb adjustment assembly of the flashlight of the invention. 
     FIG. 2E is a perspective view of the printed circuit board containment plate of the bulb adjustment assembly. 
     FIG. 3 is a cut-away side view of the bulb adjustment assembly inserted into the flashlight of the invention. 
     FIG. 4 is a cut-away axial view of the endcap assembly of FIG.  1 . 
     FIG. 5 is a cut-away top view of the endcap assembly of FIG.  1 . 
     FIG. 6 is a partially exploded perspective view of the side mounted switch circuit assembly of FIG.  1 . 
     FIG. 7, is a front axial view of the first circuit board of the switch circuit assembly. 
     FIG. 8 is a rear axial view of the first circuit board of the switch circuit assembly. 
     FIG. 9 is a front axial view of the lamp bulb circuit board. 
     FIG. 10 is a rear axial view of the lamp bulb circuit board. 
     FIG. 11 is a cut-away side view of a retaining ring securing the switch circuit assembly in an endcap. 
     FIG. 12 is a cut-away front axial view of FIG.  11 . 
     FIG. 13 is a cut-away side view of the end mounted switch assembly. 
     FIG. 14 is a side view of the flashlight of FIG. 1 attached to an expandable baton. 
     FIG. 15 is a cut-away side view of the joint between the flashlight and baton of FIG.  14 . 
     FIG. 16 is a cut-away side view of a lamp storage plug. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1,  2   a , and  2   b  the flashlight of the present invention is shown and designated as  10 . Flashlight  10  is generally comprised of a flashlight body  20 , a head  30 , and a switch assembly  40 . Flashlight body  20  is constructed in part of a battery tube  202  characterized by a barrel section  204  and an integral lamp head section  206  having a flared or bowl shape relative to the diameter of barrel section  204 . Barrel section  204  is provided with external threads at  210  while lamp head section  206  is provided with external threads at  211 . Adjacent threads  210  is an annular groove  212  for receipt of an o-ring  213 . A sleeve  209  is disposed over the unthreaded portion of barrel section  204 . Barrel section  204  is disposed for receipt of one or more energy cells  214 , each energy cell  214  having a positive contact  216  and a negative contact  218 . Energy cells  214  are preferably, but not by way of limitation, 3 volt lithium batteries, although any standard energy cell may be utilized. 
     Head  30  is comprised of a lens ring  302 , a lens  308 , a reflector  310  and a lamp assembly  320 . Lens ring  302  is defined by a first end  303  and a second end  305 . An annular shoulder  304  is disposed at first end  303  about the inner diameter of ring  302 . At second end  305 , ring  302  is provided with internal threads  306  for engagement with external threads  211  of lamp head section  206  such that lens  308 , reflector  310  and lamp assembly  320  are secured within the bowl of lamp head section  206 . 
     In FIGS. 3 and 2 d , lamp assembly  320  includes lamp  321 , a base or circuit board  322 , outer adjustment ring or assembly member  323 , non-conductive fasteners  324 , board containment plate or outer clamp  325 , and bulb shock absorber  326 . Outer adjustment ring  323  and board containment plate  325  are formed of electrically conductive material. Lamp  321 , which is generally commercially available, comprises a filament  328  disposed within a bulb  329  having a neck section  330  from which extends a positive pin  331  and a negative pin  332 . Lamp  321  is mounted on circuit board  322 . Lamp bulb  321  is preferably, but not by way of limitation, 6 volt halogen lamp bulb, although any standard lamp bulb may be utilized. 
     With particular reference to FIGS. 9 and 10, circuit board  322  has a positive side  334  and a negative side  336 . Positive side  334  is characterized by a positive electrode  338  and negative side  336  is characterized by a negative electrode  340 . A positive pin receptacle  341 , a negative pin receptacle  342 , and fastener bores  343  extend between side  334  and side  336 . Positive pin receptacle  341  is in electrical contact with positive electrode  338  and negative receptacle  342  is in electrical contact with negative electrode  340 . Positive and negative pin receptacles  341 ,  342  are disposed for receipt of positive and negative pins  331 ,  332  of lamp  321 , respectively. 
     Turning back to FIGS. 3 and 2 d , outer adjustment ring  323  has a through bore  344  in which is defined a first internal radial shoulder  346  and a second internal radial shoulder  348 . Threaded fastener bores  350  are disposed coaxially within shoulder  348 . Externally, adjustment ring  323  is provided with a gripping surface  352  and threads  353  with an o-ring groove  354  disposed therebetween. Circuit board  322  seats within through bore  344  such that negative electrode  340  of board  322  abuts second shoulder  348 , establishing electrical contact therebetween. In addition, threaded fastener bores  350  of adjustment ring  323  are axially aligned with fastener bores  343  of board  322 . 
     Board containment plate  325  is disposed adjacent the positive side  334  of board  322  to contain board  322  within adjustment ring  323 . Containment plate  325  has a first surface  356  and a second surface  357 . Countersunk through bores  358  extend from first surface  356  while a countersunk bore  359  extends from second surface  357 . Plate  325  also includes an annular shoulder  360  defined between first surface  356  and second surface  357 . When disposed to contain board  322 , surface  357  of plate  325  abuts positive electrode  338  of board  322 , establishing electrical contact therebetween. Countersunk bore  359  is provided to permit positive and negative pin receptacles  341 ,  342  to extend through board  322  without interference by plate  325 . This is especially desirable since negative pin receptacle  342  is part of the flashlight&#39;s negative circuit. Countersunk bores  358  axially align with threaded fastener bores  350  of adjustment ring  323  and fastener bores  343  of board  322  to permit non-conductive threaded fasteners  324  to extend through plate  325  and to threadingly engage threaded fastener bores  350  such that board  322  is secured within ring  323 . Bores  358  are countersunk to permit electrical contact between first surface  356  of plate  325  and positive terminal  216  of energy cell  214  without interference by connectors  324 . Those skilled in the art will understand that the diameter of second surface  357  of plate  325  is preferably smaller than the diameter defining first shoulder  346  of ring  323  such that plate  325  and ring  323  are not in electrical contact. 
     As mentioned above, one important feature of the present invention is bulb shock absorber  326 . Shock absorber  326  comprises an annular plug  362  having an axial slot  364  and through bores  366  extending from the base of slot  364 . Shock absorber  326  is disposed for receipt of lamp  321 . Specifically, the narrow neck  330  of lamp  321  seats within slot  364  while the positive and negative pins  331 ,  332  of lamp  321  extend through bores  366 . When lamp  321  is mounted in board  322  secured within ring  323 , shock absorber  326  seats within bore  344  of ring  323 . Shock absorber  326  is preferably formed of a high heat material. 
     As shown in FIG. 1, lamp adjustment assembly  320  is threadingly engaged to reflector  310 . The reflector  310  is provided with a cylindrical socket member having inner peripheral female threads to mate with the outer peripheral threads of ring  323 . When so joined, electrical contact is established between adjustment ring  323  is and reflector  310 . Reflector  310  is provided with a first end  367  and a second end  368 . A through bore  370  extends from second end  368  and intersects the base of a parabola  371  extending from first end  367 . Through bore  370  includes internal threads  372  that are disposed for engagement with external threads  353  of lamp adjustment assembly  320  (See FIG.  3 ). An o-ring or friction member  374  is mounted within groove  354  to prevent inadvertent movement of lamp adjustment assembly  320  relative to reflector  310 . As explained above, reflector  310  mounts within the bowl of lamp head section  206 . Specifically, the outer surface of reflector  310  seats within head  206  such that electrical contact is established therebetween such as at  376 . 
     Lens  308  rests against first end  367  of reflector  310 . In the preferred embodiment, a gasket  309  is disposed around lens  310  to protect lens  310  and to seal head  206 . Lens ring  302  fits around gasket  309  and lens  308  such that shoulder  304  abuts gasket  309 . Preferably, lens  310  is further protected by providing shoulder  304  with a comparatively large axial thickness such that lens  310  is set inward from first end  303  of ring  302 . As explained above, the second end  305  of ring  302  is provided with internal threads  306  for engagement with external threads  211  of lamp head section  206 . When ring  302  is tightened onto head section  206 , lens  308 , reflector  310  and lamp assembly  320  are secured within the bowl of lamp head section  206 . 
     Turning now to switch assembly  40  as is best shown in FIGS. 1 and 2 c , the assembly includes an endcap or closure  402  having a first end  404  and a second end  406 . A first axial bore  408  extends from first end  404  and a second axial bore  409  extends from second end  406 . First axial bore  408  is internally threaded at  414  while second axial bore  409  is internally threaded at  415 . Bore  408  extends to intersect a cavity  410  defined within endcap  402  (FIG.  5 ). An annular shoulder  412  is provided at the intersection of cavity  410  and bore  408 . Extending radially from shoulder  412  are fastener bores  418  (FIG.  5 ). First axial bore  408  may further include an annular channel  416  between threads  414  and shoulder  412 . 
     Cavity  410  is separated from second axial bore  409  by a dividing wall  420 , and further includes a step  422  at wall  420 . An aperture  424  joins cavity  410  with a countersunk radial bore  426  provided in the outer surface of endcap  402 . At the base of countersunk bore  426  is an o-ring groove or continous channel  428 . 
     Disposed within endcap  402  is a switch circuit assembly  430  (FIG. 6) which comprises a first circuit board or base  432 , a second circuit board or secondary base member  434 , a switch  436 , and a spring  438  the spring  438  functions are a conductive element. With reference to FIGS. 7 and 8, first circuit board  432  has a first side  440  and a second side  441 . Defined on first side  440  is a first electrode  442  and a second electrode  443 . Defined on second side  441  is a third electrode  445  and a fourth electrode  446 . A central bore  448  extends between first side  440  and second side  441  for receipt of an electrically conductive threaded nipple  450  (FIG. 6) that is in electrical contact with both first electrode  442  and third electrode  445 . Spring  438  (FIG. 6) attaches to nipple  450  and is therefore in electrical contact with third electrode  445 . Fastener holes  451  and a slot  452  are disposed about the peripheral edge of board  432 . Fastener holes  451  are electrically conductive such that second and fourth electrodes  443 ,  446  are in electrical contact. Finally, electrically conductive pin holes  453 ,  454 , and  455  are aligned about central bore  448 . Pin holes  454  are in electrical contact with first and third electrodes  442 ,  445 . Likewise, pin holes  453  are in electrical contact with second and forth electrodes  443 ,  446 . 
     Second board  434 , which has a first side  458  and a second side  459 , is similarly provided with a number of electrodes. Specifically, board  434  has a first electrode  460 , a second electrode  462  and a third electrode  463 . Board  434  also has electrically conductive pin holes  464 ,  465 , and  466  that are aligned about the major axis of board  434 . Pin hole  464   a  is in electrical contact with first electrode  460 , pin hole  464   b  is in electrical contact with second electrode  462 , and pin holes  465  are in electrical contact with third electrode  463 . 
     Those skilled in the art will understand that the second side  459  of board  434  may be similarly configured as first side  458  to aid in the assembly of switch circuit assembly  430 . Board  434  further defines a tab  468  which is disposed to seat in slot  452  of first board  432  to permit first board  432  to be joined with second board  434 . When first board  432  is joined with second board  434 , third electrode  445  of first board  432  is in electrical contact with third electrode  463  of second board  434 , and fourth electrode  446  of first board  432  is in electrical contact with first and second electrodes  460 ,  462  of second board  434 . 
     As is best seen in FIG. 6, switch  436 , which is generally commercially available, is of the push-button type and is provided with a plunger  470 , and a number of electrical attachment pins  471 ,  472 ,  473 , which are disposed for receipt in holes  464 ,  465 ,  466  of second board  434 . The plunger function or a switching element in this switch assembly those skilled in the art will understand that switch  436  is generally designed for internal attachment to circuit boards used in electronic devices that are significantly free of moisture and debris. Such switches are typically characterized by very quiet operation due to their size and construction. Another feature of such switches is that they are characterized by at least two plunger positions. In a first plunger position, the switch is open, while in a second plunger position, in which the plunger is depressed, the switch is closed. Furthermore, when the plunger is only partially depressed, such switches typically permit electrical contact. Still yet another characteristic of such switches is that they are provided with dual pins for each plunger position. 
     When switch  436  is attached to board  434 , plunger  470  can be manipulated to establish electrical contact between first, second and third electrodes  460 ,  462 ,  463  of second board  434 . Specifically, when plunger  470  is depressed, a closed electrical circuit is established between first, second and third electrodes  460 ,  462 ,  463  of second board  434 . As such, an electrical current applied to spring  438  passes through nipple  450 , into third electrode  445  of first board  432 , into third electrode  463  of second board  434 , into switch  436  via pins  472 , out of switch  436  via pins  471 , into first and second electrodes  460 ,  462  of second board  434  and into fourth electrode  446  of first board  432 . Furthermore, since fastener holes  451  establish electrical contact between fourth electrode  446  and second electrode  443  of first board  432 , second electrode  443  is also included in the closed circuit. 
     Turning back to FIGS. 1 and 2 c , switch circuit assembly  430  is disposed within endcap  402  such that second circuit board  434  rests on step  422  and first circuit board  432  abuts annular shoulder  412 . In the preferred embodiment, the height of step  422  is large enough to preclude switch pins  471 ,  472 ,  473  extending through board  434  from contacting endcap  402 . When seated in this manner, plunger  470  is axially aligned with aperture  424 , fastener holes  451  of first board  432  are axially aligned with fastener bores  418  of endcap  402 , and spring  438  is axially aligned with first axial bore  408  of endcap  402 . Additionally, when board  432  is seated against shoulder  412 , fourth electrode  446  of board  432  overlays shoulder  412  such that shoulder  412  and fourth electrode  446  are in electrical contact. In one embodiment, electrically conductive, press fit pins  476  may be disposed through fastener holes  451  and into fastener bores  418  to retain board  432  against shoulder  412 . In another embodiment (FIGS.  11  and  12 ), an electrically conductive annular retaining ring  413  may be disposed in annular channel  416  to retain board  432  against shoulder  412 . Retaining ring  413  overlays second electrode  443  of board  432  to provide electrical contact between endcap  402  and second electrode  443 . 
     Another important feature of switch assembly  40  is switch cover or switch activation element  480  which protects switch circuit assembly  430  from moisture and debris. Switch cover  480  is integrally formed of a bowl shaped section  482 , an o-ring  483  disposed about the open end of bowl shaped section  482 , and a stem  484  attached to the interior of bowl section  482  and axially aligned therewith. Switch cover  480  is disposed within bore  426  and above plunger  470  of switch  436 , such that o-ring  483  sealingly seats in o-ring groove  428  and stem  484  is axially aligned above plunger  470 . Stem  484  functions both to provide support to bowl section  482  and to engage plunger  470  when switch cover  480  is depressed. Switch cover  480  may be formed of any resilient material, such as, by way of example, rubber. 
     With reference to FIG. 1, switch assembly  40  is secured to barrel section  204  by way of mating threads  210  and  414  such that o-ring  213  sealingly engages bore  408 . In the preferred embodiment, sleeve  209 , when disposed over barrel section  204 , is of the same outer diameter as endcap  402  such that sleeve  209  provides an additional seal against the migration of moisture and debris between switch assembly  40  and barrel section  204 . In the preferred embodiment, cover  209  is formed of a foamed vinyl. 
     The electrical circuit of the flashlight of the preferred embodiment will now be summarized. Positive terminal  216  of fuel cell  214  bears against circuit board containment plate  325  which is contact with the positive pin  331  of lamp  321  via positive electrode  338  of circuit board  322 . Negative pin  332  of lamp  321  is in contact with negative electrode  340  of circuit board  322 . Board  322  is urged against shoulder  348  of adjustment ring  323  such that adjustment ring  323  and negative electrode  340  are in contact. Adjustment ring  323  is threadingly engaged with reflector  310  to provide electrical contact therebetween. Reflector  310  seats within lamp head section  206  at  376 . Lamp head section  206  and barrel section  204  are integrally formed and provide an electrical current path to endcap  402 , which is in electrical contact with section  204  by way of engagement threads  414 . Endcap  402  includes an annular shoulder  412  against which first circuit board  432  abuts. When so disposed, the fourth electrode  446  of circuit board  432  is in contact with shoulder  412 . Second circuit board  434  is attached to first circuit board  432  such that fourth electrode  446  is in contact with first and second electrodes  460 ,  462  of board  434 . Switch  436  is attached to board  434  and, when closed, provides an electrical path between first and second electrodes  460 ,  462  of board  434  and third electrode  463  of board  434 . Third electrode  463  is in contact with third electrode  445  of first board  432 . Third electrode  445  of board  432  is in contact with nipple  450  mounted within board  432 . Attached to nipple  450  is spring  438  which bears against the negative terminal  218  of energy cell  214 , thus completing the circuit. It should also be noted that the threaded end of barrel section  204  bears against second electrode  443  of first circuit board  432 , providing additional electrical contact between barrel section  204  and switch circuit assembly  430 . 
     Those skilled in the art will understand that those components of flashlight  10  which are utilized to conduct an electric current are formed of any electrically conductive material such as by way of example but not limitation, aluminum. 
     As mentioned above, endcap  402  is also provided with a socket having internal threads  415  disposed within second bore  409 . This end of the endcap  402  functions as an adapter for securing the flashlight to other implements. This configuration permits attachment of other instruments, such as expandable batons, nightsticks or firearms. The instruments are generally provided with external threading to mate with the internal threads of the endcap. With reference to FIGS. 14 and 15, the flashlight  10  of the current invention is shown attached to an expandable baton  60 . Expandable baton  60  includes a handle  602  having a first end  604  and a second end  606 . First end  604  is provided with external threads  605 , while a handle cover  607  is disposed around the unthreaded portions of handle  602 . Mounted within handle  602  are multiple, nested extension sections  608 ,  610  of decreasing diameter. An enlarged tip  612  may be attached to the end of the outermost extension section  610 . In the extended position, section  608  seats within second end  606  of handle section  602  and section  610  seats within the distal end of section  608 . In the retracted position (FIG.  14 ), sections  608  and  610  are retained within handle  602  by a retaining clip (not shown)  614 . Specifically, the retaining clip mounts on retaining clip plate  616  which abuts first end  604  of handle  602  such that the retaining clip  614  extends into the interior of handle  602 . Retaining clip plate  616  is generally secured to handle section  602  by an endcap (not shown) threadingly engaged to external threads  605 . 
     As shown in FIG. 15, internal threads  415  of endcap  402  are disposed for engagement with external threads  605  of baton  60  such that flashlight  10  and baton  60  may be joined together. Retaining clip plate  616  abuts dividing wall  420  and seats against first end  604  of handle  602  such the retaining clip  614  extends into the interior of handle  602 . In a preferred embodiment, flashlight  10  is of the same outer diameter as baton  60  such that a smooth, continuous surface is formed between flashlight  10  and baton  60 . 
     When endcap  402  is not attached to other instruments, a plug  650  (FIG. 16) is provided to mount within second bore  409  of endcap  402 . Plug  650  is defined by a first end  652  and a second end  654 . A shallow first bore  656  is provided in first end  652 , while a second bore  658  extends axially from second end  654 . The external surface of plug  650  has an annular shoulder  660  and threads  662 , with an annular groove  664  disposed therebetween. An o-ring  666  mounts within groove  664 , while a sleeve  668  lines the interior of second bore  658 . An identification plate  670  mounts within first bore  656  such that plate  670  is flush with the surface of plug  650 . When plug  650  is mounted within second bore  409  of endcap  402 , sleeve lined second bore  658  may be utilized to store a replacement light bulb  321 . Those skilled in the art will understand that sleeve  668  is provided to cushion bulb  321  when disposed within bore  658 , and as such, may be formed of any suitable material, such, as by way of example only, foam, rubber, or other resilient or shock absorbing material. 
     FIG. 13 illustrates another embodiment of flashlight  10  in which side mounted switch assembly  40  is replaced with rear mounted switch assembly  50 . Switch assembly  50  includes an endcap  502  having a first end  504  and a second end  506 . A first bore  508  extends axially from first end  504  and intersects a second bore  509  which extends axially from second end  506 . An annular shoulder  510  is defined at the intersection of first and second bores  508 ,  509 . An o-ring groove  512  is provided around the inner periphery of second bore  509  adjacent second end  506 . Threads  514  are provided around the inner periphery of first bore  508 . Extending radially from shoulder  510  are fastener bores  516 . First axial bore  508  may further include an annular channel  518  between threads  514  and shoulder  510 . 
     Mounted within endcap  502  is switch circuit assembly  520  which generally comprises a circuit board  432  to which is attached a switch  436  and a spring  438 . With reference to FIGS. 6,  7 , and  8 , spring  438  is mounted in the manner shown and described above. Board  432 , which is used to assemble switch circuit assembly  430 , may also be used to assemble switch circuit assembly  520  by utilizing electrically conductive pin holes  453 ,  454 ,  455 . Specifically, the electrical attachment pins  471 ,  472 ,  473  of switch  436  are received in pin holes  453 ,  454 ,  455 . When switch  436  is attached to board  432 , plunger  470  can be manipulated to establish electrical contact between first and third electrodes  442 ,  445  and second and fourth electrodes  443 ,  446 . Specifically, when plunger  470  is depressed, a closed electrical circuit is established between the electrodes of board  432 . As such, an electrical current applied to spring  438  passes through nipple  450 , into third electrode  445 , into switch  436  via pins  472 , out of switch  436  via pins  471 , and into fourth electrode  446 . Furthermore, since fastener holes  451  establish electrical contact between fourth electrode  446  and second electrode  443 , second electrode  443  is also included in the closed circuit. 
     Turning back to FIG. 13, switch circuit assembly  520  is axially disposed within endcap  502  such that board  432  abuts shoulder  510  and switch  436  extends into second bore  509 . Switch circuit assembly  520  may be attached to endcap  502  utilizing either roll pins  476  inserted through fastener holes  451  and into fastener bores  516  or retaining ring  413  inserted within annular channel  518 . In any event, when board  432  is seated against shoulder  510 , fourth electrode  446  overlays shoulder  510  such that shoulder  510  and fourth electrode  446  are in electrical contact. 
     Switch cover  480  is disposed within bore  509  such that o-ring  483  sealingly seats in o-ring groove  512  and stem  484  extends into bore  509  toward plunger  470 . Switch assembly  50  is secured to barrel section  204  by way of mating threads  210  and  514 . When secured in this manner, flashlight  10  is provided with an end mounted operation switch that is sealed within the interior of flashlight  10 . 
     One important feature of end mounted switch assembly  50  is its interchangeability with side mounted switch assembly  40 , from both a manufacturing perspective and a user&#39;s perspective. During manufacture, the only additional element of assembly  50  that is not utilized in assembly  40  is endcap  502 . Assembly  50  utilizes each of the other components of assembly  40  except the additional circuit board  434 . Those skilled in the art will appreciate that such a configuration lowers both cost and time of manufacture. End mounted switch assembly  50  also adds an additional degree of flexibility to flashlight  10  through the interchangeability of switch assemblies  40  and  50 . A user can easily reconfigure a flashlight  10  disposed for mounting on an accessory to a flashlight  10  with an end mounted activation switch by simply unscrewing one endcap and replacing it with the other endcap. The electrical path through end mounted switch assembly  50  is substantially the same as described above for flashlight  10  configured with side mounted switch assembly  40 . Specifically, endcap  502 , which is attached to barrel section  204 , is in electrical contact with barrel section  204  by way of engagement threads  514 . Endcap  502  includes an annular shoulder  510  against which first circuit board  432  abuts. When so disposed, the fourth electrode  446  of circuit board  432  is in contact with shoulder  510 . Switch  436  is attached to board  432  and, when closed, provides an electrical path between fourth electrode  446  and third electrode  445 . Third electrode  445  is in contact with nipple  450  mounted within board  432 . Attached to nipple  450  is spring  438  which bears against the negative terminal  218  of energy cell  214 , thus completing the circuit. It should also be noted that the threaded end of barrel section  204  bears against second electrode  443  of first circuit board  432 , providing additional electrical contact between barrel section  204  and switch circuit assembly  520 . 
     The above-described flashlight provides an electrical circuit that is less subject to wear and shock than prior art flashlights. This is accomplished by incorporating one or more printed circuit boards. The benefits of such board include the limited number of moving parts that could be subjected to wear and shock. In addition, the printed circuit boards function as a means for dissipating shock to individual electric components such as the switch and the lamp bulb. Such components are typically the most fragile elements of a flashlight assembly. The circuit boards also permit enhanced electrical contact throughout the circuit. For example, by incorporating a wide electrode that is in electrical contact with the entire surface area of a shoulder or other component feature, there is less chance that the circuit will be interrupted. On the other hand if a wire or metallic strip were used to establish a discrete contact point, as is done in prior art flashlights, damage to that discrete point could cause the entire circuit to be interrupted. Thus, the circuit boards of the invention permit a much greater contact area, enhancing the durability of the flashlight. 
     Another unique feature of the flashlight is the lamp adjustment assembly. The assembly is positioned interior of the flashlight and can only be altered by partially disassembling the head of the flashlight. As described, the assembly not only permits adjustment of the lamp bulb relative to the reflector, but also utilizes the contact between the two components to facilitate the electric circuit between the positive terminal of the battery and the flashlight barrel. 
     Several unique features of the flashlight are also found in the switch assemblies. Whether side mounted or rear mounted, the assemblies provide nearly silent, push button switches at the end of the flashlight, and the switches are multi-functional, having both an intermittent activation position, i.e. a deadman switch, and a continuous activation position. 
     The switches are further protected by a unique switch cover that is integrally formed of an o-ring to enhance sealing of the switch compartment. 
     The side mounted switch assembly additionally provides the feature of permitting attachment of the flashlight to an additional accessory, such as an expandable baton. The unique construction of the flashlight is even more desirable when used in combination with such batons because expandable batons typically are subjected to sharp blows, especially as the baton sections are being collapsed back into the baton handle. When not attached to a baton, the open end of the switch assembly can be used to store additional lamp bulbs by attaching an end plug over the open end. 
     The interchangeability the side mounted and end mounted switch assemblies is also unique, permitting a user to configure the flashlight as desired, without greatly increasing the cost of manufacture of the assemblies to the interchangeability of the internal components of the switch assemblies. 
     While certain features and embodiments of the invention have been described in detail herein, it will be readily understood that the invention encompasses all modifications and enhancements within the scope and spirit of the following claims.