Abstract:
A portable reading light has a telescoping arm that is slidable within a housing, the arm having a light source at the end thereof which has one or more light emitting diodes which provide bright light, low power consumption and durability. The light emitting diodes preferably are located in an articulatable light support and disposed adjacent to a focusing lens to better direct and shape the light onto a surface. The arm is mounted to a base assembly slidable within the housing and being telescopically expandable for stabilizing the arm when set for use.

Description:
TECHNICAL FIELD  
       [0001]     This invention relates to a portable reading light and more particularly to a portable clip-on reading light which has a telescoping arm and improved illumination.  
       BACKGROUND  
       [0002]     Portable clip-on reading lights are known. For example, a book light such as that disclosed in U.S. Pat. No. 4,432,042 has a base, an integral clamp from which a vertical lamp bearing arm is mounted to one end with the other end supported by the base. These devices typically comprise a body having means to clip on to a surface, such as a book cover, and include an arm that may be flexible or foldable for aligning a light for illuminating, for example, a page of a book.  
         [0003]     Generally, such lights are popular but they do suffer from several drawbacks. Typically, illumination is provided by an incandescent bulb which itself has a limited life and such bulbs are often sensitive to shock during handling and are also difficult to replace. The sensitivity to shock promotes early bulb failure. In addition, power consumption is rather high which may result in reduced battery life and therefore frequent battery replacement. Often, the bulb is somewhat underpowered and therefore the amount of illumination may dim significantly over time leading to possible eye strain. Lastly, while folding and bending arms are useful, these do require additional space and any effort to reduce the size or bulkiness of the portable reading light promotes its portability and convenience for the user.  
       SUMMARY OF THE INVENTION  
       [0004]     It is an object of the invention to provide a clip-on reading light with increased bulb life.  
         [0005]     It is a further object to provide a clip-on reading light which has increased battery life.  
         [0006]     It is yet another object to provide a clip-on reading light with improved illumination.  
         [0007]     It is yet another object to provide a clip-on reading light that is compact and light weight.  
         [0008]     These and other objects of the present invention are achieved by a portable reading light having a housing, a power source disposed in the housing, a telescoping arm having an articulatable light source at the outer end thereof, the arm being mounted on a base, slidable within the housing for storing the telescoping arm therein. The light source comprises at least one light emitting diode (LED). Preferably, a magnifying lens is located adjacent the LED for directing and focusing the light emitted therefrom. The housing has means for clipping onto the surface of an object. Preferably, the light source comprises a plurality of light emitting diodes, most preferably three LEDs, which are set at specific angles relative to each other and disposed adjacent one or more magnifying lens which focus and direct the light for improved illumination.  
         [0009]     Utilizing the present invention, a compact portable reading light is provided with an articulatable light that not only illuminates a page but which is rugged, and is low power consuming yet provides particularly bright white light without substantial dimming, for promoting long term reading with limited eye strain. Incorporating the telescoping arm within the housing also provides a compact device since the arm is stored within the housing when not in use. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]      FIG. 1   a  is a side view of the portable reading light of the present invention with the telescopic arm extended;  FIG. 1   b  is a perspective view showing the portable reading light from an alternate angle.  
         [0011]      FIG. 2  is a top perspective view of the portable reading light with the arm collapsed and stored in the housing.  
         [0012]      FIG. 3  is a cross-sectional view of the portable reading light with the arm collapsed within the housing.  
         [0013]      FIG. 4  is a cross-sectional view of the portable reading light with the arm extended outside of the housing.  
         [0014]      FIG. 5   a  is an enlarged cross-sectional view of the arm pivot;  FIG. 5   b  is a cross-sectional view with the arm coaxial with the housing;  FIG. 5   c  is a view with the block collapsed within the housing.  
         [0015]      FIG. 6  is a cross-sectional view of the arm in the extended position.  
         [0016]      FIG. 7  is a top view of the lamp support assembly of the present invention,  
         [0017]      FIG. 7   a  is a view taken along line A-A thereof,  
         [0018]      FIG. 7   b  is a view taken along line B-B thereof,  
         [0019]      FIG. 7   c  is a view taken along line C-C thereof,  
         [0020]      FIG. 7   d  is a view taken along line D-D thereof and  
         [0021]      FIG. 7   e  is a view taken along line D-D thereof and  FIG. 7   e  is a view taken along line E-E thereof.  
         [0022]      FIGS. 8   a - c  are views showing how each LED illuminates a specific page portion, relative to its angle in the lamp support. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0023]     Referring to  FIG. 1   a , a portable reading light  1  has a housing  2  having a clip  3  on a side  4  thereof. The clip pivots on a hinge  5  and is biased by a spring  6 . The light has a slidable base  7  with a pivot  8  supporting a telescoping arm  9  which has three sections,  9 A,  9 B and  9 C. An outer pivot  10  is located at an outer end of the arm section  9   c  and has a light support  11  rotatably mounted thereto, within which are disposed three light emitting diodes  12 . In  FIG. 1   a , the portable reading light is shown extended for use.  FIG. 1   b  shows the extended light at an alternate angle, the light emitting diodes  12  and disposed behind individual magnifying lenses  12   a  which focus the light to improve lighting on the surface illuminated as will be described further below. Using directed light significantly improves readability over the use of LEDs alone.  
         [0024]     Referring to  FIG. 2 , the portable reading light  1  has the arm  9  stored within the housing  2 , and the light support  11  received within a socket  13  at a forward end  14  of the housing. Thus, the portable reading light is shown in a compact form for storage. A sliding switch  15  is provided on a side  16  of the housing for ease in actuating the light. In this position, the portable reading light can function as a flashlight.  
         [0025]     Referring to  FIG. 3 , the reading light housing  2  is shown in cross-section. A power source  17  is located within the housing  2  for powering the light. While various configurations are possible, in this embodiment, 3 AAA size battery receiving slots  18  are provided and interconnected by conductors  19  to the switch  15 . The switch is slidable, having on and off positions. A flexible pair of conductors, shown as a single wire  20 , pass from the switch to and through the arm  9  which includes a wire storage chamber  21  therein. The wire storage chamber is sized for receiving a sufficient length of wire as would be needed for connecting to the light source when the telescoping arm is in the extended position. When the telescoping arm is collapsed, the wire bunches or coils within the chamber. Sufficient wire must be provided to reach the bulbs in the lamp support when in the extended position.  
         [0026]     Referring to  FIG. 4 , the arm  9  is fully out of the housing  2 . The slide block  7  is positioned adjacent to the lamp support receiving socket  13  at the forward end of the housing. The slide block is an assembly of three components including a first base  14  having a section slidable within a second base  15  slidable within a third base  16 . The bases collapse together when set for storage but extend when in use to add stability to the extended arm. The first base  14  has slots  17  on each side  18 . The slots  17  are received in corresponding slots  19  in the second base  15 . Similarly, within the third base  16 , the pivot portion  8  has slots  20  for receiving the second base but only when the arm is coaxially aligned, so that the arm is locked in this position when the second base is received within the third base. Each of the first and second bases have a responsive projection  21  and  22  that ride on rails  23  disposed on opposite sides of an arm receiving chamber  24  within the housing. A stop  25  is provided at the forward end of the rails to stop the forward movement of the base, so that it does not exit the housing. Each of the second and first bases have downwardly projecting prongs  26  that are received in a pair of grooves  27  within the housing. The grooves provide stability for the arm as well. The third base similarly has prongs  28  that slide within the slots of the second base.  
         [0027]     In operation, these bases slide into each other to form a compact slidable block when the arm is stored within the housing, but have an extended form when the arm is pulled out of the housing.  
         [0028]     Referring to  FIG. 5   a - b , the pivot  8  is shown in cross section, with the bases fully extended. The pivot itself has detents  30  that receive stops  31  for providing a ratchet type pivoting, that is, the pivot moves in increments. This prevents slippage of the light from the optimum angle set by the user. The pivot has a circular support  32  with a flat side  33  for locking the pivot in the coaxial position for storage. A cylinder portion  34  extends through the second and third bases for additionally locking the pivot for storage.  
         [0029]     Two projections  35  are received within detents  36  disposed in supporting the opposed side walls  37  within the housing so as to semi-permanently lock the slide block in position when the lamp is in the received position.  
         [0030]     Referring to  FIG. 5   b , the pivot  8  for the arm  9  is engaged to the base, having a plurality of slots  30  that act as stops for receiving a pair of projections  31  extending from a rotating portion of the pivot. These slots receive the projections therein so as to semi-permanently lock the arm in different angular positions to allow the user to set the arm at particular angles for reading and thereby prevent the arm from pivoting inadvertently. The projections and slots lock in a sufficient amount to prevent rotation of the arm, yet allow the locking to be overcome by manual pressure when the arm is manipulated for storage.  
         [0031]     Referring to  FIG. 6 , the arm is extended, with the bulbs  12  in the lamp support connected to the power supply in the housing. Similar slots and projections are used to lock the lamp support in the socket in the housing and to lock the base in the forward most position.  
         [0032]     The light emitting diodes alone do not provide satisfactory lighting for reading as the light emitted from the diode has a directivity angle. The angle either focuses the light in a bright circular spot or scatters the light for greater illumination coverage but with a loss of light intensity, as either the light is uneven, or too diffused for successful use as a reading light.  
         [0033]     Referring to  FIGS. 7-7   e , the present invention overcomes these deficiencies by incorporating a magnifying lens  32  adjacent to an LED  33  which captures the light emitted and changes the directivity angle and converts it preferably to a closely rectangular shape, increasing the efficiency for illuminating a specific area of a reading page. The lens spreads the light which would otherwise be too concentrated on a focal point, while avoiding over diffusion of the light to too large of an area. If not filtered by the lens, the light is also too white which results in too much reflection back to the reader, which is annoying and may strain and tire the eyes.  
         [0034]     As seen in  FIG. 7 , a lamp support  34  has three light emitting diodes  33   a, b  and  c  each of which is set at a specific angle. As shown in  FIGS. 7   a ,  7   b  and  7   c , these are 35, 28.5 and 22 degrees, respectively though other angles could also be used. As shown in  FIGS. 8   a ,  8   b  and  8   c , placing the LED&#39;s at these angles, and illuminating through the associated lenses  32   a, b  and  c , provides illumination of a full page, each LED illuminating a particular portion of the page.  
         [0035]     One or more magnifying lenses can be used with one or more single or multiple LED configurations. However, one LED may be insufficient to provide even light distribution on a page, and about three LED&#39;s are preferred in one embodiment, the magnifying lens may be adjusted so that the light overlaps from each LED on or about the same rectangular space, providing an additive effect. This may be useful for longer extension embodiments.  
         [0036]     Alternatively, and preferably, each LED can be focused on different portions of a page, so as to cover more area, for example, one covers the top of a page, a second covers a middle of a page and a third covers a bottom of a page. The direction and area covered are a function of the magnifying/focusing lens design. This works quite well with the telescoping arm, as adjusting the distance of the light source from the page allows a user to adjust the area covered, as well as intensity.  
         [0037]     The circuitry for powering the LED&#39;s preferably includes means to enhance LED life. In one embodiment, each LED  33   a, b  and  c  has a resistor  35   a, b  and  c  which prevents overloading the LED&#39;s with too much voltage or current. In addition, each LED has an associated heatsink  36   a, b  and  c  which are integrated into a simple heatsink to draw heat away from the LED&#39;s and prevent damage from overheating. Preferably, a single heat sink  36  is used for all the LED&#39;s.  
         [0038]     While preferred embodiment of the present invention have been shown and described it will be understood by those skilled in the art that various changes or modification could be made without varying from the scope.