Abstract:
A flashlight includes a body with a head, the head having a central axis. A light source is coupled to the body and a lens assembly is rotatably coupled to the head. The lens assembly has a rotational axis and a plurality of filters offset from the rotational axis such that rotation of the lens assembly places different filters on the output side of the light source. The rotational axis of the lens assembly is substantially aligned with the central axis of the head.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a light with colored lenses. In particular, the present invention relates to an improved system for providing mechanically selectable colored lenses for a light.  
       BACKGROUND OF THE INVENTION  
       [0002]     The need for color filtered light is common among hunters, stargazers, and military and security personnel engaged in covert operations. Color filtered light is preferable to white light in that it helps preserve the night vision of the user and nearby individuals. Additionally, filtered light may be more difficult to detect by observers, particularly hostile observers equipped with modem image-intensifiers.  
         [0003]     One challenge to providing a system for color filtering a light source is to make the filter mechanism simple to operate. If there are multiple or complex control inputs, a user may accidentally turn on a white light source at a high setting and thus negatively impact the user&#39;s night vision with a flash of bright light, or give away the user&#39;s location to a hostile observer.  
         [0004]     Another challenge to providing a system for color filtering a light source is to enable the user to select the operating mode of the light by tactile sensation only, under conditions of total darkness. In some circumstances, the user may be unwilling to turn the light on until the light is properly set, thus ensuring that detection or loss of night vision does not occur.  
         [0005]     One way of providing color filters for a light is to provide translucent lenses in various colors that the user may insert in place of a transparent bulb cover, as disclosed in U.S. Pat. No. 4,697,890 to Crookston. However, a disadvantage of this approach is that changing the filter color of the light requires disassembly and reassembly. This may be difficult to accomplish in the dark, and may be a slow, time-consuming process. Also, disassembly increases the chances of dropping and possibly losing critical parts during the exchange process. Additionally, the use of separate filters presents the disadvantage of having loose parts, which require storage when not in use. Loose parts are also more vulnerable to loss during periods of disuse than filters that are an integral part of the light.  
         [0006]     Another approach to providing a variable color light source is to use independent lamps or bulbs, each of a different color or with a separate color filter. However, the use of multiple bulbs increases the number of component parts and raises the cost of manufacturing such a flashlight. Furthermore, the control of multiple light sources may require either more user inputs or more complex electronic switching to take advantage of the separate bulbs. Additional switches or more complex controls may also increase the risk of user error, which could negatively impact the operator&#39;s night vision or increase the chance of detection. Additional controls may also raise the cost of manufacturing, and possibly make the device more prone to failure..  
         [0007]     Yet another approach to providing a variable color light source is to use a single lamp or bulb, and a wheel fitted with a variety of colored filters, as disclosed in U.S. Pat. No. 3,936,164 to Cohen et al. However, the light disclosed therein is bulky and awkward, in part due to the significant difference in diameter between the flashlight body and the attached color wheel. Further, the rotational axis of the color wheel is parallel to, but offset from, the longitudinal axis of the flashlight body. As a result, the color wheel extends to one side of the flashlight, producing a lopsided and awkward instrument.  
         [0008]     Accordingly, there is a need for a color filtered light that is both simple to operate and quickly changeable by the user, even under conditions of total darkness. Further, there is a need for a color filtered light that is reliable, convenient to use, and contains a small number of inexpensive components.  
         [0009]     It would be desirable to provide a system and/or method that provides one or more of these or other advantageous features. Other features and advantages will be made apparent from the present specification. The teachings disclosed extend to those embodiments that fall within the scope of the appended claims, regardless of whether they accomplish one or more of the aforementioned needs.  
       SUMMARY OF THE INVENTION  
       [0010]     The invention relates to a flashlight having a body with a head, the head having a central axis. A light source is coupled to the body and a lens assembly is rotatably coupled to the head. The lens assembly has a rotational axis and a plurality of filters offset from the rotational axis such that rotation of the lens assembly places different filters in front of the light source. The rotational axis of the lens assembly is substantially aligned with the central axis of the head.  
         [0011]     The invention further relates to a flashlight having a body with a head, and a light source coupled to the head. A lens assembly is rotatably coupled to the head, the lens assembly including a plurality of filters. An indexing mechanism is coupled to the head and engages the lens assembly to snap the lens assembly into a selected rotational position.  
         [0012]     The invention further relates to a flashlight having a body with a head, and a light source coupled to the body. A lens assembly is rotatably coupled to the head, the lens assembly including a plurality of filters. The flashlight further includes an alignment mechanism set in the head and set in the lens assembly providing tactile information regarding a position of the lens assembly.  
         [0013]     The invention is capable of other embodiments and of being practiced or carried out in various ways. Alternative exemplary embodiments relate to other features and combinations of features and may be generally recited in the claims. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a perspective view of a light equipped with a rotatable lighting head mechanism;  
         [0015]      FIG. 2  is an exploded perspective view of a rotatable lighting head mechanism;  
         [0016]      FIG. 3  is an exploded perspective view of a rotatable lens assembly;  
         [0017]      FIG. 4  is an exploded perspective view of the rotatable lens assembly of  FIG. 3  from a different direction; and  
         [0018]      FIG. 5  is a sectional view of a rotatable lighting head mechanism. 
     
    
     DETAILED DESCRIPTION  
       [0019]     Referring to  FIG. 1 , according to an exemplary embodiment of the present invention, a light, shown as a flashlight  10 , includes a body  12  and a lighting head mechanism  14 . The body  12  may be cylindrical or another shape, and may be made of metal, plastic, or other materials. The body  12  may contain batteries or another power source. The body  12  may contain additional internal wiring or a switch, which may be embodied in a variety of types and configurations as is generally known in the art.  
         [0020]     Further referring to  FIG. 1 , the lighting head mechanism  14  includes a head shell  18  and a rotatable lens assembly  24 . In a preferred embodiment, the head shell  18  is fixed in rotational position relative to the body  12 . The lens assembly  24  is capable of unlimited free rotation in either direction relative to the head shell  18 . However, in an alternative embodiment, the lens assembly  24  may be fixed relative to the flashlight body  12 , and the head shell  18  capable of free rotation with respect to both the flashlight body  12  and the lens assembly  24 .  
         [0021]     In an exemplary embodiment, body  12  is cylindrical and has a longitudinal axis  60 , and the head shell  18  has a central axis  62  in alignment with the longitudinal axis  60 . The lens assembly  24  is positioned so that it has a rotational axis  64  aligned with the longitudinal axis  60  of the body  12  and the central axis  62 . In embodiments where the body  12  is of a different shape or orientation, the longitudinal axis  60  may not align with the rotational axis  64 , or the body  12  may not have a readily ascertainable longitudinal axis. However, the rotational axis  64  will generally be substantially aligned with the central axis  62  of head shell  18 .  
         [0022]     The head shell  18  and lens assembly  24  may be provided with an alignment mechanism, shown as alignment flats  40  and  42 . The user may align flats  40  and  42  to rotate the lens assembly  24  to a known position with respect to the head shell  18  using tactile or visual senses. In alternative embodiments, the alignment flats  40  and  42  may be replaced with a raised edge, raised dots, grooves, or depressions that similarly provide the user with a tactile or a visual indicator of the rotational position of the lens assembly  24 .  
         [0023]     Referring to  FIG. 2 , according to an exemplary embodiment, the lighting head mechanism  14  includes a light source  16 , a head shell  18 , a light source housing  20 , a light mount  38 , an indexing mechanism, shown as detent mechanism  22 , and a rotatable lens assembly  24 . The light source  16  is offset from the rotational axis  64  (see  FIG. 1 ) of the lens assembly  24 , such that rotation of the lens assembly  24  will present one of a number of filters/lenses  34  to the light source. In a preferred embodiment, light source  16  is a light emitting diode (LED). In alternative embodiments, the light source  16  may be a conventional bulb, such as an incandescent, halogen or krypton bulb, or any other source of light.  
         [0024]     The light source housing  20  is sized to fit within the head shell  18 . In the embodiment depicted in  FIG. 2 , the light source housing  20  fits snugly within the head shell  18 , and is rotationally fixed with respect to the head shell  18  by a tab  44  that engages a corresponding slot in the head shell  18 . The light source housing  20  surrounds the light source  16 , and prevents light leakage to ensure that light emanating from the light source  16  will be constrained to passing through only one filter/lens  34  (see also  FIGS. 3 and 4 ). In addition, the light source housing  20  is shown with locking tabs  46  to engage corresponding recesses in the detent mechanism  22  to maintain the detent mechanism  22  rotationally fixed with respect to the light source housing  20 . In alternative embodiments, the detent mechanism  22  may instead be formed as one integral piece with the light source housing  20 , or secured to the housing  20  by an adhesive or fastener. The light source housing  20  may further incorporate a reflector, appropriate to the type of bulb or light source used, as is generally known in the art.  
         [0025]     Further referring to  FIG. 2 , the light source  16  is secured to light mount  38 . In an exemplary embodiment, the light source  16  is an LED, affixed to the light mount  38 . If other bulb types are used, the light source  16  may be connected to the light mount  38  by a threaded connection, a bayonet connection, or other connection types as are known to the art. The light mount  38  may further contain mounting posts, electronic controls, battery terminals, switches, or any method of support or control of the light source  16 .  
         [0026]     Further referring to  FIG. 2 a  passageway  52  in the detent mechanism  22  provides an unobstructed path from the light source  16  to the filters/lenses  34 . A set of spring arms  48  of the detent mechanism  22  engage the rotatable lens assembly  24 . The detent mechanism  22  provides tactile feedback to the user and allows the user to quickly and accurately place the lens assembly  24  in proper alignment with light source  16 . In combination with the alignment flats  40  and  42 , the detent mechanism  22  allows selection of a proper filter in all operating conditions, including complete darkness, prior to activation of the light.  
         [0027]     Referring to  FIGS. 1 and 2 , the rotatable lens assembly  24  is secured to the head shell  18  in a manner that allows free rotation about the central axis  62  of the head shell  18 . As shown, a filter ring  36  provides a one-way snap engagement with a recessed channel  50  located in the inner circumference of the head shell  18 . The filter ring  36  is also provided with a knurled edge, allowing the user to easily rotate the lens assembly  24 .  
         [0028]     Referring to  FIGS. 3 and 4 , the rotatable lens assembly  24  further includes a gasket  30 , a filter plate  32 , a number of filters/lenses  34 , and the filter ring  36 . The filter plate  32  has a number of notches  26 . The individual filters/lenses  34  are set into the filter ring  36 , and held in place by the filter plate  32 . The notches  26  of the filter plate  32  are engaged by the spring arms  48  (See  FIG. 2 ) of the detent mechanism  22  to provide indexed rotation of the lens assembly  24 . In an exemplary embodiment, the gasket  30  provides a seal between the filter ring  36  and the head shell  18 .  
         [0029]     Further referring to  FIGS. 3 and 4 , the filters/lenses  34  may be clear, or various colors, or polarized. Additionally, the filters/lenses  34  may be configured to selectively transmit various non-visible ultraviolet or infrared wavelengths of light. In an exemplary embodiment, the filters/lenses  34  are blue, green, red, and clear. The number and type of the filters/lenses  34  may be varied with the size of the lighting head mechanism  14 , the power of the light source  16 , and the needs of the user.  
         [0030]     Referring to  FIG. 5 , the lighting head mechanism  14  is shown according to an exemplary embodiment. The head shell  18  may be provided with a threaded connection to couple the head shell  18  to the body  12 . In alternative embodiments, the body  12  and head shell  18  may be a single contiguous piece, secured with adhesive, snapped into position, or otherwise secured. The light source  16  is presented with a single filter/lens  34 , while the light source housing  20  prevents light leakage to other filters/lenses. As shown, the alignment flats  40  and  42  are aligned.  
         [0031]     In operation, a user may readily switch the flashlight  10  between available color filter positions by grasping the body  12  or head shell  18 , and applying a rotational torque to the rotatable lens assembly  24 . The user may detect a positive tactile feedback as the spring arms  48  of the detent mechanism  22  engage the notches  26  of the filter plate  32 , ensuring that the chosen filter/lens  34  will be placed in proper position to allow an unobstructed pathway from light source  16  to the environment. The user may further employ the alignment flats  40  and  42  to place the rotatable lens assembly  24  in a known position relative to the head shell  18  prior to activation of the light source  16 . As this procedure does not necessarily rely on any visual cues, the user may perform color selection even in conditions of total darkness. Once the rotatable lens assembly is in a known position, other filters/lenses  34  may be selected by rotation of the lens assembly  24  a predetermined number of steps to the right or left, as indicated by tactile feedback from the detent mechanism. Additional tactile cues may be provided on the lens assembly  24  or the head shell  18  to further specify the precise rotational position of the lens assembly  24  during operation.  
         [0032]     According to an exemplary embodiment, the present invention provides an improved method for switching a single light source between a variety of colors, in a form that is easy and convenient to use. The present invention avoids the use of spare or loose parts, and allows the user to operate the invention solely by tactile feedback, thus allowing operation in conditions of total darkness. By aligning the rotational axes of the lens assembly and the head, the present invention also provides a balanced light without a lopsided appearance or feel. The present invention also uses avoids the use of more complex electronic controls to vary the color output, thus improving reliability and durability.  
         [0033]     While the detailed drawings and specific examples given herein describe various exemplary embodiments, they serve the purpose of illustration only. It is to be understood that the invention is not limited in its application to the details of construction and the arrangements of components set forth in the preceding description or illustrated in the drawings. For example, the particular detent mechanism and head configuration is but one way of attaching indexing a rotatable lens assembly. Furthermore, other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangements of the exemplary embodiments without departing from the scope of the invention as expressed in the appended claims.