Abstract:
A lighting system that includes a light bulb having a threaded bulb base and a luminare socket. The bulb ( 200 ) includes a two conductor base ( 201, 205 ) while the luminare socket ( 300 ) utilizes a circular ring ( 305 ) with an open aperture ( 307 ) for supplying current to the bulb. The circular ring ( 305 ) and aperture ( 307 ) in the luminare socket are sized to provide contact with the center contact ( 205 ) of the light bulb when the preferred wattage is selected. This prevents over wattage light bulbs from being used avoiding excess heat, arcing and the potential for fire.

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to electric incandescent light bulb bases and more particularly to a modified incandescent light base and luminare socket for selecting appropriate bulb wattage. 
   BACKGROUND 
   Today&#39;s common household incandescent light bulb bases and receiving sockets remain compatible with Thomas Edison&#39;s design. Such compatibility is useful, but it prolongs a safety issue that has increased substantially since Mr. Edison&#39;s day. As seen in prior art  FIG. 1A , the typical Edison bulb  100  includes the bulb  101  and lower section having a threaded base  103  which fastens within an accompanying luminare socket. Prior art  FIG. 2  illustrates the bottom view of the Edison or threaded base wherein a contact  105  located at the center of the concentric conductor  107  is used to supply electrical current to filaments (not shown) within the glass envelope. The contact  105  and concentric conductor  107  are insulated from the threaded base  103  using an insulative material  109 . The threaded base  103  screws into an accompanying luminare socket (not shown) that is connected to a lamp or other electrical device. The luminare socket typically uses a flat spring bar which makes electrical contact with a corresponding contact  105  on the bottom of the threaded base  103 . Luminare socket manufacturers typically apply warning labels or other indicia on the luminare socket with recommendations for the maximum wattage bulb that is to be used with the base. When these recommendations are followed, this limits both the heat generated by the bulb and electrical current used by the device. 
   Those skilled in the art will recognize that there is no way to assure that these recommendations to consumers will be followed. For example, a 200-watt incandescent bulb is the same size as a 40-watt bulb, but it generates much more heat when illuminated. Excessive heat can deteriorate the insulation both on the electrical wires connecting to the luminare socket and on the supply wires in the junction box above the luminare. This deterioration, typically in the form of brittleness and cracking, can lead to arcing, and a subsequent fire. 
   Previous inventors have made adjustments to Edison&#39;s light bulb base design. U.S. Pat. No. 656,284, which is incorporated by reference herein, teaches the use of bulb tips having various sizes to prevent other bulbs or fuses from being interchanged. U.S. Pat. No. 4,456,322, which is also incorporated by reference herein, discloses lamp wattage limiting devices that use a contact having a predefined geometric configuration to define the bulb wattage that may be used on the luminare socket. U.S. Pat. Nos. 2,519,328; 2,701,868; 2,999,220; 3,131,986; 3,309,646; and 5,401,191, which are all incorporated by reference herein, show various contact and socket base configurations that allow use with multiple filament bulbs. 
   Consequently, the need exists for a bulb and luminare socket where the maximum wattage of the bulb is controlled by the socket of the luminare. Moreover, any newly designed light bulb bases must be compatible with existing Edison sockets, and existing light bulbs must work in at least some of the newly designed sockets. 

   
     BRIEF DESCRIPTION OF THE FIGURES 
     The accompanying figures, wherein like reference numerals refer to identical or functionally similar elements throughout the separate views, and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
       FIG. 1  is a prior art diagram illustrating a side perspective view of a standard light bulb with Edison base. 
       FIG. 2  is a prior art diagram illustrating a bottom view Edison bulb base as seen in  FIG. 1 . 
       FIGS. 3 ,  4  and  5  are bottom perspective views of the modified Edison base in accordance with an embodiment of the invention. 
       FIG. 6  is a top perspective view of a modified luminare socket in accordance with an embodiment the invention. 
       FIG. 7  is a side cross-sectional view of the modified luminare socket as shown in  FIG. 6 . 
       FIG. 8  is a chart illustrating the approximate size of the contacts on the modified Edison base and luminare socket in accordance with the invention. 
   

   Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. 
   DETAILED DESCRIPTION 
   Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to a modified Edison light base and luminare socket. Accordingly, the apparatus components and method steps have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
   In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. 
   As illustrated in  FIGS. 3–5 , the invention involves modifying both the light bulb base as well as the luminare socket used with the base. Although a standard Edison bulb base is described herein, those skilled in the art will recognize that any oversized light bulb and luminare socket would benefit from the advantages of the invention, as would multifilament, or three-way, luminare sockets. These oversized light bulb bases and luminare sockets are also known as moguls. 
     FIG. 3  illustrates a modified light bulb base where the contact at the bottom of the bulb base is specifically sized to be small, typically 3 millimeters (mm) in diameter.  FIG. 4  illustrates a modified light bulb base where the contact at the bottom of the bulb base is 8 mm in diameter.  FIG. 5  illustrates a modified light bulb base where the contact at the bottom of the bulb base is 13 mm in diameter. Each bulb base  200  includes the standard sized threaded base  201 , an insulative material  203  and a center contact  205   a ,  205   b , or  205   c  specifically sized so as to operate with a specific type of luminare socket. As seen in  FIGS. 3–5 , the size of the contact  205   a ,  205   b , or  205   c  will vary with the wattage of the bulb. Thus, a light bulb greater than 100 watts will feature a small contact  205   c  which has a diameter typically 3 mm in size. A bulb between 61 watts and 100 watts will use a slightly larger contact  205   b  with a diameter that is approximately 8 mm in size while a bulb 60 watts or less will use the largest contact  205   a  that is approximately 13 mm in diameter. 
     FIGS. 6 and 7  illustrate top and cross-sectional views, respectively, of an accompanying luminare socket  300  in accordance with the invention. As with the standard luminare socket, the modified luminare socket  300  includes a circular outer shell  301 . The outer shell  301  is electrically conductive and includes threaded sides  302  on the inner side of the shell for receiving the threaded base of the modified Edison bulb. An insulating material  303  such as rubber, plastic or the like is used to insulate the contact ring  305   a  or  305   b  from the outer shell  301 . The contact ring  305   a  or  305   b  is a metallic conductive material that is substantially circular having an internal hole or aperture  307   a  or  307   b . The contact ring  305   a  or  305   b  further includes a flat extension  309  at one end for attaching a wire conductor using a rivet or other fastener. Together, the contact ring  305  and the flat extension  309  form a resilient spring similar to the one in current usage. The flat extension  309  is typically connected with the “hot” wire of a 120-volt alternative current (AC) power source. Another rivet  311  is used at the outer shell  301  for also connecting a wire conductor typically used for carrying the grounded (neutral) current to the outer shell. 
   In operation, it should be evident to those skilled in the art that the modified Edison base and contacts  205   a ,  205   b  or  205   c  work in combination with the luminare socket and contact rings  305   a  or  305   b , respectively, to control the bulb wattage that may be used with that specific luminare socket For example, a light bulb over 60 watts with a small center contact  205   b  or  205   c  will not make an electrical connection with contact ring  305   a , with its 11 mm aperture  307   a . Instead, the center contact may make harmless contact with the insulating material  303  or make no contact at all. Thus the bulb, while fitting in the screw shell socket, will not illuminate.  FIG. 8  is a chart that illustrates the approximate sizing relationship between the light bulb wattages and contacts  205   a ,  205   b  and  205   c , contact rings  305   a  and  305   b , apertures  307   a  and  307   b , and the flat spring contact (not shown). 
   Since luminare sockets designed for over 100 watt incandescent bulbs must permit all bulbs 100 watts or less to also illuminate, the present flat spring type of contact in the socket is the preferred design for these sockets. The flat spring contact allows proper electrical contact with each of the modified bulb bases having contacts  205   a ,  205   b  and  205   c . Luminare sockets designed for light bulbs over 60 watts and up to 100 watts must permit 60-watt or lower light bulbs to also illuminate, thus their aperture size  307   b  is 6 mm. Therefore, light bulbs with contacts  205   a  and  205   b  will make electrical contact and illuminate when screwed in, while light bulbs with contact  205   c  will not make a connection. Luminare sockets designed only for light bulbs 60 watts or lower feature an aperture size  307   a  of 11 mm, permitting only light bulbs with contacts  205   a  to illuminate. 
   Multifilament or three-way, light bulbs benefit from this invention without revising the light bulb design. The bottoms of their bases feature a center “hot” contact and another one off center. The receiving socket for three-way light bulbs would be modified to include a center contact, preferably spring-mounted for positive contact, as shown in U.S. Pat. Nos. 803,246; 1,774,517; 2,890,435; and 3,890,027, and a large resilient ring with a wide aperture for the second “hot” contact. Insulating material  303  will separate the center spring contact from the resilient ring  305   a  when the bulb is screwed into the modified luminare socket  300 . 
   Given that the invention specifies at least three electrical device base designs and corresponding socket designs, color-coding the insulating material  203  and  303  is suggested but not required. For example, yellow, orange and red insulation would identify lower, medium and higher wattage bases and sockets, respectively. Such color-coding would facilitate the use of properly sized light bulbs or devices in the luminares or apparatus. 
   Thus, the invention describes a modified electrical contact system for the Edison screw-in base and receiving socket, with three ranges of electrical current. It permits current to flow to the lowest range device when the device is screwed into any of the three sockets. It permits current to flow only to the medium range device when the device is screwed into the medium or high range socket. It permits current to flow only to the high range device when the device is screwed into a high range socket. The design modification to the screw-in base is that the center contact at the bottom of the base is to be a specific diameter, with a certain amount of variation acceptable, to correspond to an associated socket. The design modifications to the corresponding sockets are the contact rings having apertures in various sizes that prevent higher wattage devices using smaller contacting bases from making any electrical contact with the ungrounded or “hot” side of the socket. 
   In the description and drawings referenced above, the common light bulb has been used to explain the invention&#39;s modifications to the Edison screw base design. However, it is not the inventor&#39;s intention to limit the benefits of the invention to light bulbs, but instead to extend them to all uses of the screw base design. 
   In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.