Abstract:
The present invention provides a unique dual mode, inline switch mechanism that is fully integrated into the rear cap of a flashlight assembly to provide a completely self contained and waterproof switching mechanism. The switch assembly further provides dual mode functionality including an ON position and a momentary ON position while also including a reliable OFF position that prevents the accidental activation of the light when the user desires that it remain off. The entire mechanism resides in the end cap of the flashlight assembly and includes an end cap structure that is designed to be rotatably attached to the end of a flashlight housing, a contact plate, a plunger, an insulator disk and an elastomeric cover. The switch mechanism is fully integrated on the interior of the flashlight providing the highly desirable, fully contained, in line functionality.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is related to and claims priority from earlier filed provisional patent application No. 60/353,367, filed Feb. 1, 2002. 

   BACKGROUND OF THE INVENTION 
   The present invention relates generally to a dual mode switch for improved functioning in flashlight devices. More specifically, the present invention relates to an improved pushbutton switching mechanism for flashlights that provides a momentary and constant ON feature as well as a positive, reliable OFF position. 
   Flashlights of varying sizes and shapes are generally well known in the art. A number of such designs are known that utilize two or more batteries as their source for electrical energy. Typically, these batteries are carried in series in a tubular body, where the tubular body also serves as a handle for the flashlight. In order to operate the flashlight, an electrical circuit is established from one terminal of the battery, through a conductor to an external switch located in an opening in the side of the tubular body and then through another conductor to one contact of a bulb. After passing through the filament of the bulb, the electrical circuit emerges through a second contact of the bulb in electrical contact with a conductor, which in turn is in electrical contact with the flashlight housing. Finally, the flashlight housing provides an electrically conductive path to the other terminal at the rear of the battery. Actuation of the external switch completes the electrical circuit selectively enabling electrical current to pass through the filament of the bulb, thereby generating light that is then typically focused by a reflector to form a beam of light. 
   In general, the above described flashlight switch mechanisms operate in two basic manners. The first method of operation is a pushbutton type switch on the side or bottom of the light. The user depresses the switch, which has an internal mechanism that locks in the engaged position, turning the flashlight on. To turn the light off, the user again depresses the switch, unlocking it and turning the light off. This design has several drawbacks. One drawback is that the increased number of parts creates additional assembly steps and increases the difficulty of assembly process. Another drawback is that when a flashlight of this type is stored in luggage, it is susceptible to being compressed by items that may shift during transit, thereby activating the flashlight and draining the battery. A further drawback associated with this possibility of accidental activation is evident in high intensity flashlights that generate a great deal of heat during operation. If a flashlight of this type is tightly packed in luggage and accidentally activated, it may cause a fire. 
   In an attempt to resolve the drawbacks noted above, with respect to the push-button type switches, a second type of rotatable switch was developed for in-line use in flashlights. In one design, an end cap is rotatably secured to the flashlight body. To establish the required electrical contact, the end cap is rotated making contact between the rear contact of the batteries and the housing of the flashlight thereby energizing the circuit and illuminating the lamp bulb. A number of such prior art designs feature rotatable end caps which are rotated to move the batteries longitudinally within the flashlight body towards the lamp bulb, thereby causing contact between the battery contact and the base contact of the lamp bulb. In the open position, the battery is typically spring biased away from the base contact of the bulb. In other designs, miniature flashlights have been designed where the rotatable switch is located in the reflector end of the flashlight body. The lamp bulb is located within an insulated receptacle at the reflector end of the flashlight with one or more conductive pins being rotatably aligned by movement of the switch portion of the device to establish electrical contact. While these switch mechanisms are internal to the device and thus less subject to damage, they are overly complicated in design thereby requiring higher assembly tolerances, which result in making them more costly to manufacture. 
   There is therefore a need for a unique flashlight switching design that provides dual mode functionality with a reliable OFF position that has improved functionality over the designs of the prior art. There is a further need for a flashlight switch device that requires a reduced number of parts thereby simplifying assembly and manufacture while providing the necessary dual mode functionality described above. 
   BRIEF SUMMARY OF THE INVENTION 
   In this regard, and in furtherance of the above stated objectives, the present invention provides a unique dual mode, inline switch mechanism that is fully integrated into the rear cap of a flashlight assembly to provide a completely self contained and waterproof switching mechanism. The switch assembly further provides a reliable OFF position that prevents the accidental activation of the light when the user desires that it remain off. 
   The entire basic structure of the switch of the present invention resides in the end cap of the flashlight assembly and includes an end cap structure that is designed to be rotatably attached to the end of a flashlight housing, a contact plate, a plunger, an insulator disk and an elastomeric cover. Only the contact plate in the assembly of the present invention is required to be conductive. The end cap structure may be conductive so that its material is consistent with the material used in the outer housing of the flashlight however this is not required. The remaining components however are all electrically insulative and designed to properly isolate the conductive components to insure proper operation of the switch assembly. The plunger and contact plate are assembled and supported in an opening in the insulator disk. The insulator disk is then further assembled into the end cap. This provides for the plunger and contact plate to be located in a position at the rear of the flashlight where its motion is limited to a controlled and predictable linear travel. As can be seen, in this manner a switch assembly that operates in an in-line fashion is provided. 
   By limiting the travel of the plunger and contact plate to a predictable distance, the present invention can achieve the desired multifunctionality, namely, a momentary ON function, a full ON function and a verifiable OFF function. Each one of the functions is selected by rotating the end cap assembly including the switch of the present invention. As the end cap of the assembly is rotated, its linear spacing relative to the flashlight housing is increased or decreased thereby altering the mode of switch operation. In this manner an economical flashlight assembly is provided that has a reduced number of operational parts as compared to the prior art thereby producing a more reliable product. 
   Accordingly, one of the objects of the present invention is the provision of a low cost flashlight having a superior dual mode switching mechanism. Another object of the present invention is the provision of a flashlight having a dual mode switching mechanism that includes a momentary ON, a full ON and a verifiable OFF position. A further object of the present invention is the provision of a flashlight having a dual mode switch that includes a reduced number of moving components thereby reducing manufacturing and assembly costs while improving the reliability of the assembly. Yet a further object of the present invention is the provision of a flashlight assembly having a dual mode switch that is integrated in an inline fashion and is waterproof. 
   Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings which illustrate the best mode presently contemplated for carrying out the present invention: 
       FIG. 1  is a perspective view of a flashlight employing the dual mode switch assembly of the present invention; 
       FIG. 2  is a cross-sectional view thereof taken along Line  2 — 2  of  FIG. 1 ; 
       FIG. 3  is an enlarged cross-sectional view thereof in the OFF position; 
       FIG. 4  is an enlarged cross-sectional view thereof in the momentary ON position; 
       FIG. 5  is a cross-sectional view of an alternative embodiment thereof in the OFF position; and 
       FIG. 6  is a cross-sectional view of the alternate embodiment in  FIG. 5  in the ON position. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring now to the drawings, a flashlight including an end cap with the dual mode switch of the present invention is illustrated and generally indicated at  10  in  FIGS. 1–4 . Further, a second embodiment of the present invention is shown in  FIGS. 5 and 6 . In accordance with the present invention, an in-line flashlight is provided having a momentary ON, full ON and confirmable OFF position. The entire operational part of the switch component is incorporated into the end cap  10  of the flashlight battery housing  12 . 
   Referring now to  FIGS. 1–4 , a pushbutton type switch is shown incorporated into the end  10  of a flashlight assembly. The flashlight has a battery housing  12  that is tubular in shape and is electrically conductive. An end cap  10  is threadedly received onto the end of the battery housing  12 . A spring  14  is received into the battery housing  12  and is in electrical communication with one contact of a lighting element  16  located at the end of the battery housing  12  opposite the cap  10 . The second contact of the lighting element  16  is in electrical communication with the interior wall of the battery housing  12 . Batteries  18  are inserted into the battery housing  12  so that one end of the lower battery is in electrical communication with the spring  14 . The cap  10  is threaded onto the battery housing  12  thereby retaining the batteries  18  between the spring  14  and the end cap assembly  10 . 
   The end cap  10  further contains all of the operational elements of the switch mechanism of the present invention. The end cap  10  may or may not be constructed of electrically conductive material and includes an axial opening  20  on the end surface. An elastomeric sealing gasket  22  is seated in the end of the cap  10  covering the switch plunger  24  and waterproofing the switch assembly. The switch assembly is comprised of an insulating support disc  26 , a plunger  24  slideably received through an axial bore  28  in the disc  26  and a switch plate  30 . After the plunger  24  is inserted through the axial bore  28  in the disk  26 , the switch plate  30  is affixed to the protruding end of the plunger  24 . In this manner, once the plunger  24  and switch plate  30  are assembled, they can no longer be removed from the disk  26 . When assembled, the switch plate  30  and plunger  24  are slideably movable within the axial bore  28 . The insulator disk  26  is preferably a plastic material that is press fit into the cap  10  so that it remains in place when the flashlight is disassembled for servicing the batteries  18 . The switch plunger  24  has a shaft and an enlarged head that is inserted through the axial bore  28  in the center of the insulator disk  26 . The switch plate  30  is connected to the protruding end of the shaft of the plunger  24  either through the use of a fastener, an adhesive or through press fitting the switch plate  30  to the receiving end of the plunger  24 . Once the end cap  10  is fully assembled, it can be seen that the travel, “T”, of the switch assembly is limited to the distance between the enlarged head of the switch plunger  24  and the insulator disk  26 . The end cap  10  is then threaded onto the end of the battery housing  12  wherein the threaded portion engages the threaded end of the battery housing  12 . 
   In operation, it can be seen that the batteries  18  are spring biased by spring  14  in a direction towards the rear of the battery housing  12  and towards the end cap  10 . The second contact of the batteries is in constant contact with the center of the switch plate  30 . When the cap  10  is threaded onto the flashlight, it begins to press the batteries  18  downwardly into the battery housing  12 . The batteries  18  further press upwardly causing the switch plate  30  to move into contact with the underside of the insulator disk  26 . With the cap  10  only partially threaded onto the battery housing  12 , it can be seen that if the distance, “D”, between the electrically conductive battery housing  12  and the switch plate  30  is greater than the maximum travel distance of the switch assembly, the flashlight remains OFF and cannot be energized by pressing the switch because the gap “D” is too great to be overcome by the travel “T” of the switch. The limited travel of the switch is important in defining the function of the switch. In this position, the flashlight is in a confirmed OFF position. When the cap  10  is further threaded onto the battery housing  12  and the distance “D” between the switch plate  30  and the battery housing  12  is no longer greater than the travel “T” of the switch components, the switch can be depressed, pushing the batteries  18  downwardly, allowing the switch plate  30  to come into momentary contact with the battery housing  12  and momentarily energize the flashlight. If released, the batteries  18  push the switch plate  30  back breaking the contact between the battery housing  12  and the switch plate  30 , thus providing a momentary ON function. Finally, if the cap  10  is fully threaded onto the battery housing  12 , the switch plate  30  is pressed downwardly by the insulator disk  26  that is contacting its back side causing the switch plate  30  to be held in rigid contact with the battery housing  12  energizing the flashlight circuit in a full ON function. 
   Turning to  FIGS. 5 and 6 , a second embodiment of the present invention is shown. The operational concept of the switch is the same as described above. If the cap  100  is fully threaded onto the battery housing  102 , the flashlight is energized in a full ON mode. If the cap  100  is partially unthreaded, pressing the center of the cap  100  activates the switch for a momentary ON mode. By further unthreading the cap  100  beyond the travel limit of the switch, a confirmed OFF position is reached. The mechanics of the switch elements in this embodiment, however, are different than those described above. The end cap  100  in this embodiment is formed from an elastomeric material and an annular metal ring  104 . The metal ring  104  is integrally threaded and engages with corresponding threads on the end of the battery casing  102 . The end cap  100  further includes a conductive center contact  106 , integrally molded into the elastomeric cap  100 . Rather than including a plunger to which the switch plate is connected, the switch plate  108  is fastened to the center contact  106  of the end cap  100 . As described above, the battery  110  is spring biased against the center of the switch contact  106  and presses the switch plate  108  and cap center  106  normally away from the battery housing  102 . In this regard, the upper surface  112  of the switch plate  108  includes a layer of electrical insulation. The insulation prevents an electrically conductive path from forming through the upper surface  112  of the switch plate  108  and the annular ring  104 , which in turn is threaded onto the main battery housing  102 . When the center of the elastomeric end cap  100  is pressed, it deflects inwardly causing the switch plate  108  to press the battery  110  downward and allowing the outer edge of the lower surface  114  of the switch plate  108  to contact the battery housing  102  thereby energizing the circuit. When released, the end cap  100  returns to its normal, non-deflected position pulling the switch plate  108  from the battery housing  102  and turning the flashlight off. If the end cap  100  is fully threaded onto the battery housing  102 , the lower surface  114  of the switch plate  108  is held in contact with the battery housing  102  resulting in fully energizing the flashlight. 
   The present invention also anticipates that the push button switch may be employed as one component in the switching and function selection on a flashlight. For example, in addition to using the switch of the present invention, a flashlight may also incorporate electronics and a selector switch to further selectively energize the flashlight in a strobe or signal code manner. This also allows the end cap to be threaded on tightly under most operational circumstances. The end cap would then be unthreaded slightly to produce the momentary “on” function. Further, the switch of the present invention may be incorporated in parallel or series with other switching mechanism as have been described. 
   It can therefore be seen that the present invention provides a novel integrated in line dual mode switch assembly that enhances the function of a flashlight device. The switch assembly provides an the desirable ON, momentary ON and confirmable OFF features in a flashlight having a reduced number of operational parts, thereby enhancing the reliability of the flashlight while reducing the manufacturing costs associated therewith. Further, the present invention can be modified to accommodate a number of different flashlight configurations to create a highly useful and versatile switch assembly. For these reasons, the instant invention is believed to represent a significant advancement in the art, which has substantial commercial merit. 
   While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.