Patent Abstract:
The present invention discloses an inline switch mechanism that operates in a reverse direction, making electrical contact as the flashlight head is unscrewed. The switch has an outer housing, an inner contact tube, a plunger, a contact spring, an insulator disk and a secondary spring. All of the components are electrically conductive with the exception of the insulator disk and outer housing. In the off position, the plunger floats, centered in the contact tube, with a contact end in electrical communication with the battery. A contact spring is disposed around and in electrical communication with the plunger. The insulator disk is on the back of the plunger supporting it and isolating it from the contact tube and is disposed between the plunger and the secondary spring. The secondary spring at one end exerts pressure on the insulating disk and thereby the plunger maintaining contact on the battery and at the other end contacts one side of the LED bulbs and is in electrical communication with the contact tube.

Full Description:
PRIORITY CLAIM TO EARLIER FILED APPLICATION 
     This application claims priority from Provisional Patent Application No. 60/270,657, filed Feb. 22, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     The instant invention relates a switch mechanism that has an improved method of operation for use in flashlights. More specifically, this invention relates to an internal, inline switch mechanism for a flashlight that operates in a reverse direction to increase the reliability of the switch and provide an extended switch contact duration. 
     Flashlights of varying sizes and shapes are well known in the art. A number of such designs are known that utilize two or more batteries as their source of electrical energy, carried in series in a tubular body, where the tubular body also serves as a handle for the flashlight. Typically, an electrical circuit is established from one terminal of the battery, through a conductor to an external switch 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. 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 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, these flashlight switch mechanisms operate in two basic manners. The first mechanism is a pushbutton type switch on the side or bottom of the light. The user depresses the switch, which locks into 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. Often, if a watertight seal is desired, a rubberized material is installed into the body of the flashlight as a covering over the switch mechanism. 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 the possibility of leaks developing as the rubber membrane wears out from the stretching action resulting from continuous use. 
     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 to illuminate 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 and more costly to manufacture and require higher assembly tolerances. 
     In addition, the types of switches described above all generally operate in a forward direction, meaning that as the user turns the head or tail of the flashlight, tightening it onto the body of the flashlight, switch contact is eventually made thereby turning the flashlight on. Electrical contact, in this type of switch, is achieved by bringing a spring contact on the inside of the flashlight into contact with one pole of the battery contained within the body. These types of switches are problematic because the components of the flashlight are not always firmly holding the batteries in place. For example, when the flashlight is in the off position, the head is generally partially unscrewed from the body of the flashlight, preventing the spring on the back of the head from contacting the battery. This arrangement, however, also prevents the battery from being restrained, allowing the battery to freely float within the flashlight body. In addition, the range of switch contact is very limited, thus providing a very low tolerance switch mechanism that does not operate smoothly. 
     It is therefore and object of the present invention to provide an improved flashlight switching mechanism that is entirely self contained and completely waterproof. It is a further object of the present invention to provide a switching mechanism for a flashlight that has improved operating characteristics, such as increased contact duration and smoother operation. It is yet another object of the present invention to provide an in-line flashlight switching mechanism that is completely enclosed within the body of a flashlight thereby eliminating the possibility of contamination and damage from external forces. 
     SUMMARY OF THE INVENTION 
     In this regard, and in furtherance of the above stated objectives, the present invention provides a unique inline switch mechanism that is fully integrated into a flashlight head to provide a completely self contained and waterproof switching mechanism. The present invention further provides an inline flashlight switch mechanism that operates in a reverse direction whereby the switch makes electrical contact as the flashlight head is unscrewed. This is in contrast to the above-described switches that generally operate in a forward direction. This manner of operation allows the present invention to provide an extended operational range of positive electrical contact duration, while also producing a smoothly operating switch having broad operational tolerance. 
     The basic structure of the switch contains several operational components including a switch housing, a contact tube, a plunger, a contact spring, an insulator disk and a secondary spring. All of the components are electrically conductive with the exception of the insulator disk and the switch housing. The switch housing contains all of the other operational components of the switch and serves to selectively isolate them electrically from the body of the flashlight. In the off position, the plunger floats, centered in the contact tube, with the contact end in electrical communication with the battery. The contact spring is disposed around and is frictionally retained at the end of the plunger opposite the contact end. Both the plunger and the contact spring are in electrical communication thereby making the contact spring and plunger electrically hot. The insulator disk is installed onto the back of the plunger, supporting in the center of the contact tube and electrically isolating it from the walls of the contact tube. The insulator disk is also disposed between the plunger and the secondary spring electrically isolating these two components from one another as well. The secondary spring at one end exerts pressure on the insulating disk and thereby on the plunger maintaining the plunger in contact with the battery at all times during the operational range of the switch. At the other end, the secondary spring is in electrical communication with one contact of the LED bulbs and is also in electrical communication with the walls of the contact tube. 
     In a normally open position, the contact spring is displaced from the bottom wall of the contact tube. As the flashlight head is unscrewed the switch mechanism, retained within the head of the flashlight, moves away from the batteries while the plunger remains in place in contact with the battery due to the force of the secondary spring. Once the head is displaced far enough, the bottom wall of the contact tube comes into electrical communication with the contact spring allowing electricity to flow to the LED&#39;s. Since the spring force of the contact spring is less than that of the secondary spring, the contact tube continues to move, further compressing the contact spring while maintaining contact with the contact spring and keeping the contact end of the plunger in electrical communication with the battery as the flashlight head is turned through several rotations. 
     Other objects, features, operational details 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 containing the reverse operating switch mechanism of the present invention; 
     FIG. 2 is an exploded perspective view thereof; 
     FIG. 3 is a cross-sectional view of the flashlight of the present invention in FIG. 1 along the section line  3 — 3  in the normally open, off position; and 
     FIG. 3 a  is a cross-sectional view of the flashlight of the present invention in FIG. 1 along the section line  3 — 3  in the closed, on position. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings, a completed flashlight assembly incorporating the reverse-acting switch mechanism of the present invention is generally indicated at  12  in FIGS.  1 — 3   a.  While the reverse switch mechanism is shown incorporated into a flashlight in the description of the preferred embodiment, the present disclosure provides that the switch mechanism described can be incorporated into a variety of other devices that require an inline switch having the same or similar operational characteristics. As will hereinafter be more fully described, the present invention provides a fully contained waterproof inline flashlight switch that provides improved operating features, higher durability and easier assembly as compared to similar flashlights in the prior art. The entire assembly is contained in a simple housing to provide a useful, novel and improved light source. 
     The flashlight  12  generally includes an elongated housing  14 , batteries  16  disposed in the housing  14 , and a flashlight head portion  10 . 
     The flashlight head  10  has an outer enclosure  18  that at least partially encloses at least one light emitting diode (LED)  20 , and a circuit component  22 , as well as the reverse switch assembly. 
     The reverse switch assembly is best shown in FIG. 2, and includes a spring  24 , an insulator disk  26 , a contact spring  28 , a plunger  30 , a contact tube  32 , and a switch housing  34 . The flashlight head  10  further includes a lower enclosure  36  assembled in a permanent fashion to the outer enclosure  18  to enclose both the switching assembly and light source  20  of the flashlight  12  inside the flashlight head  10 . 
     Turning to FIG. 1 an assembled view of the flashlight  12  of the present invention is shown. The outer shape of the flashlight  12  is formed by the battery housing  14  and the outer enclosure  18  of the flashlight head  10  where the battery housing  14  also serves as the handle for the flashlight  12 . Both the battery housing  14  and the outer enclosure  18  are formed of a metallic material such as milled aluminum or stainless steel. This allows both of these components to be electrically conductive and employed as components of the overall circuitry of the flashlight  12  as will be further described below. 
     FIG. 2 shows the flashlight  12  and the flashlight head  10  of the present invention in an exploded perspective view, illustrating the general relationship between all of the components in the overall device. The battery housing  14  is generally tubular in shape having a closed bottom and an open top. The battery housing  14  is generally hollow with an opening  38  that is of a diameter particularly suited to receive batteries  16 . In the preferred embodiment, the battery housing  14  is shown of a dimension to accept two batteries  16 , however, the present invention will operate equally well using one, three, four or more batteries  16  and the length of the battery housing  14  will be adjusted accordingly to accommodate the number of batteries  16  used. The inner surface of the open end  38  of the battery housing  14  has female threads  40  that are designed to engage corresponding male threads  42  on the lower enclosure  36  thereby maintaining the flashlight  12  in an assembled condition and allowing the head portion  10  to be rotated relative to the battery housing  14 . Rotation of the head  10  relative to the housing  14  selectively adjusts the relative positions to one another. When the batteries  16  are installed into the battery housing  14  one contact of the battery  16  is in electrical communication with the bottom of the battery housing  14 . Since the battery housing  14  is metallic, electricity is therefore conducted from the battery  16  contact, through the bottom of the battery housing  14  and up through the battery housing  14  into the flashlight head  10  as will be further described below. 
     The head  10  portion of the flashlight  12  has an outer enclosure  18  that receives and houses all of the switching components and the light source of the flashlight. The outer enclosure  18  is also formed of a machined metallic material that is electrically conductive, such as machined aluminum or stainless steel. The outer enclosure  18  is cylindrically shaped, having an opening at one end into which all of the remaining components are installed and several smaller openings  44  at the other end through which the installed LED lamps  20  protrude. Circuit assembly  22  is typically a printed circuit board onto which the LED lamps  20  are mounted. The circuit assembly  22  has circuit traces connecting one pole of each LED  20  to a metal connection tab  46  and the other pole of each LED  20  to a central connection point  52  on the bottom surface of the circuit assembly  22 . Once the LED lamps  20  are installed onto the circuit assembly  22 , it is slid into the opening in the outer enclosure  18 , so that the LED lamps  20  protrude through the openings  44  in the outer enclosure  18 . The connection tab  46  is in electrical communication with the wall of the outer enclosure  18 , thereby completing a path of electrical conductivity from the first contact of battery  16 , through the battery housing  14  up into the outer enclosure  18  of the head and into the circuit assembly  22  through connection tab  46 . The remaining portion of the electrical circuit is completed through the switch components as will be discussed below. In addition to providing paths of conductivity to each of the LED lamps  20 , the circuit assembly  22  may also include additional circuitry for controlling the flow of current through the LED lamps  20  or to provide additional functionality, such as flashing, to the flashlight  12 . 
     The principal component of the switch mechanism is plunger  30 . The plunger  30  is substantially cylindrical and formed from a metallic material such as machined brass. One end of the plunger  30  is in contact with the second contact end of the battery  16  when the flashlight  12  is fully assembled. The opposite end of the plunger has a raised shoulder  48 . The raised shoulder  48  serves to retain contact spring  28  in an operative position on the plunger  30 . During assembly, the contact spring  28  is slid onto the plunger  30  and is pressed onto the raised shoulder  48  so that the spring is frictionally retained and in firm electrical communication with the plunger  30 . Further, insulator disk  26  is attached to the end of the plunger  30  opposite the battery  16  contact. This sub-assembly (plunger  30 , contact spring  28  and insulator disk  26 ) is then slid into contact tube  32 . 
     Contact tube  32  is a cylindrically shaped tube that is open on the top end and has a bottom wall. The bottom wall has an opening  54  that has a diameter slightly greater than the diameter of the plunger  30 . The remaining portion of the bottom wall forms switch contact  50 . The plunger  30 , contact spring  28  and insulator disk  26  are slid into the open end of the contact tube allowing the contact end of the plunger to protrude through the opening  54  in the bottom wall of the contact tube  32  without making physical or electrical contact with switch contact  50 . In this regard, the insulator disk  26  is sized to have a diameter that is only slightly smaller than the diameter of the contact tube  32 . This allows the insulator disk  26  to slide freely up and down inside the contact tube  32  while supporting the plunger  30  in the center of the contact tube  32  and preventing the plunger  30  from contacting the sides of the contact tube  32 . The insulator disk  26  is formed from a non-conductive material and is preferably a plastic material. Biasing spring  24  is then installed into the contact tube  32  behind the insulator disk  26 . The biasing spring  24  has a diameter that is also only slightly smaller than the inner diameter of the contact tube  32  and is in electrical communication with the inner walls of contact tube  32  and with the central connection point  52  on the circuit assembly  22  when the entire flashlight head  10  is assembled. The contact tube  32  including the switch components described above is installed into the switch housing  34 , which consists of cylindrical support housing that is electrically insulative and designed to isolate contact tube  32  from the rest of the flashlight head assembly  10 . 
     The switch housing  34 , after the above-described assembly, is then placed into the lower enclosure  36 . The lower enclosure  36  is a metallic component having an opening in its center into which the entire switching assembly is placed. The lower enclosure has an opening in its center to allow the plunger  30  to protrude and contact the battery  16  in an assembled position. The lower enclosure  36  also has male threads  42  that correspond to the female threads  40  on the interior of the battery housing  14 . To complete the assembly of the head  10 , the lower enclosure  36  containing all of the switching components, is pressed into the outer enclosure  18  using a hydraulic press (not shown) or similar method known in the art. This provides a completed flashlight head  10  that is sealed, having no parts that are accessible by the user. The head  10  is then threaded into the battery housing  14 , which already contains batteries  16  to complete the assembly of the flashlight  12 . To further seal the flashlight assembly  12  and prevent water infiltration, an O-ring gasket  56  is provided in a groove  58  in the side of lower enclosure  36 . The O-ring gasket  56  serves to seal the operable junction between the flashlight head  10  and the battery housing  14  prevent infiltration of water or other contaminants. Additionally, sealant  60  in the form of a UV curable potting compound is installed in the gap between the LED lamps  20  and the openings  44  in the outer enclosure  18  to further prevent infiltration to the interior of the flashlight  12 . 
     Turning to FIGS. 3 and 3 a , a section is shown of the flashlight  12  of the present invention in the operational state. FIG. 3 shows the flashlight  12  in the normally open, off state, and FIG. 3 a  shows the flashlight  12  in the closed, on state. In FIG. 3 the flashlight head  10  is shown threaded completely into the battery housing  14 . In this state, as can be seen, there is a gap between contact spring  28  and the bottom surface of the switch contact  50 . This gap is a break in the electrical circuit of the flashlight  12  and prevents the batteries  16  from energizing the LED lamps  20 . While plunger  30  is spring biased by the force of spring  24  in the direction of the batteries  16 , it is not allowed to move in the direction of the batteries  16  because of the proximity of the batteries  16  to the flashlight head  10 . In other words, when the flashlight head  10  is screwed entirely onto the battery housing  14 , the batteries  16  force the plunger upwardly against spring  24 . Because the spring  28  is connected to the top of the plunger, the contact spring  28  is moved out of electrical contact with the bottom of the contact tube  32 . 
     In FIG. 3 a,  the battery housing  14  is shown as being slightly unscrewed from the flashlight head  10  as indicated by the arrow  62 , or vice versa, the head  10  is unthreaded from the body  14 . This displacement of the battery housing  14  results in displacement of the batteries  16  from the flashlight head  10  by the same distance. Since the plunger  30  is spring biased in the direction of the batteries  16  by spring  24 , this linear displacement of the batteries  16  allows the spring  24  to expand and thus displace the plunger  30  rearwardly by the same distance as the battery housing  14  and the batteries  16 . Once the distance of displacement of the plunger  30  is sufficient, the contact spring  28  comes into contact with switch contact  50 . When this contact is made it can be seen that a complete electrical circuit is provided starting at the top battery  16  contact through the plunger  30 , the contact spring  24 , switch contact  50 , contact tube  32 , secondary spring  24 , central contact  52 , into the circuit assembly  22  and the LED lamps  20 , through contact tab  46 , back into the outer housing  18 , through the lower housing  36 , into the battery housing  14  and finally to the bottom contact of battery  16 . Therefore, by translating the battery housing  14  in a rearward direction  62  from the flashlight head  10  an electrical circuit is completed thereby energizing the flashlight  12 . 
     It can also be seen in FIG. 3 a  that at the point where contact spring  28  initially contacts switch contact  50 , the contact spring  28  is not compressed. Since the spring force in the secondary spring  24  is greater than the spring force in the contact spring  28 , further displacement of the battery housing  14  and batteries  16  in the rearward direction  62  allows the plunger  30  to also be further displaced in the rearward direction  62 . As the plunger  30  is further displaces by secondary spring  24 , contact spring  28  is further compressed allowing the plunger  30  to remain in contact with the battery  16  until the contact spring  28  is completely compressed. The use of the contact spring  28  and secondary spring  24  in this manner provide for the extended operational range provided for under the present invention. 
     It can therefore be seen that the instant invention provides a compact inline flashlight switching mechanism that is fully enclosed and sealed against infiltration of water of other contaminants. It can be further seen that the present invention provides a novel reverse acting switch design that provides for smooth operation and an extended operational range through the use of spring contacts. 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.

Technology Classification (CPC): 5