Abstract:
A fluorescent trouble light conversion set includes a socket adaptor which receives a single-ended fluorescent lamp and screws into a standard screw socket. A wall adaptor which plugs into an AC wall outlet is provided to supply power for the fluorescent lamp. The wall adaptor includes a housing for a ballast and transformer, and a socket for receiving the plug from a lamp having the fluorescent lamp mounted therein to supply power for the bulb. The socket is connected to the housing by a cord.

Description:
BACKGROUND OF THE INVENTION 
     The present invention pertains to compact fluorescent lights and in particular to a conversion kit by which a single ended fluorescent lamp may be provided for a lamp holder having a standard screw socket. 
     It is known to provide a single-ended fluorescent lamp with an adaptor for a standard screw socket of a lamp holder. The adaptor provides the power conversion for the fluorescent lamp and screws into a standard screw socket and includes a ballast and power converter for generating the appropriate power supply from an AC outlet to supply the fluorescent lamp, and consequently, is large and heavy. These known adaptors may not be used with lamp holders which do not have space for both the bulb and the large adaptor between the screw socket and the structure which surrounds the socket. Additionally, the heavy weight of known adaptors renders small lamps top heavy, and causes them to fall over easily. 
     One fluorescent lamp conversion kit is illustrated in U.S. Pat. No. 4,936,789. This kit includes a housing containing power conversion circuitry, and an adaptor for receiving a single ended fluorescent lamp, the adaptor including a threaded end for insertion into a standard screw socket. Because the power conversion circuitry which provides energizing and starting power for the fluorescent lamp is carried within the housing, the adaptor is relatively light weight and small in size. However, the housing has a receptacle on an exterior surface thereof which includes apertures in the housing surface for receiving plug prongs. The apertures in the housing surface allow access by insects, liquid, and debris, and thus is not well suited for outside use. Furthermore, the plug received within the socket may be easily removed, causing the circuit connection between the adapter and the lamp to be interrupted. This is especially a problem for &#34;trouble&#34; lights which are moved often to illuminate different working positions. 
     Trouble lights typically include a cage which surrounds an incandescent light bulb which is received within a screw socket therein. The use of incandescent light bulbs in trouble lights has several disadvantages. The filaments provided in incandescent light bulbs brake easily, and consequently movement of the trouble light may cause the filament to brake. Additionally, incandescent bulbs operate at high temperatures which may cause accidental burning of a user&#39;s hands and arms. Incandescent bulbs are also adversely effected by cold air, water, oil, or solvents which may come into contact with the bulbs when they are hot, and consequently cause the light bulbs to explode. 
     SUMMARY OF THE INVENTION 
     The present invention is embodied in a system having a socket adaptor receiving a single-ended fluorescent lamp, and a housing enclosing power conversion circuitry which provides energizing power to a fluorescent lamp attached thereto. More particularly, in a device embodying the invention, the housing includes a receptacle which is connected to the housing by a cord having a length of at least six inches. 
     The housing thus allows a trouble light cord to be attached to the wall plug adapter such that the respective cords may be tied together to prevent separation of the plug and the socket. Accordingly, when the trouble light is moved around by a user, the electrical connection between the trouble light and power conversion adapter is secure. Further, by providing the socket remote from the housing, the housing does not include plug receiving apertures located on the surface thereof and thus avoids entry of water to the circuitry when used in a damp environment. Furthermore, the six inch cord allows the kit to pass UL (Underwriter&#39;s Laboratories) requirements. These and other objects, advantages and features of the invention will become apparent upon review of the following specification in conjunction with the drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a trouble light having a fluorescent lamp according to the invention attached thereto. 
     FIG. 2 illustrates a wall plug adaptor according to the invention; 
     FIG. 3 illustrates a fluorescent lamp utilized by the invention; 
     FIGS. 4a and 4b illustrate a socket adaptor for us in the present invention; 
     FIG. 5 illustrates the fluorescent lamp of FIG. 2 received in the socket adaptor of FIG. 4a and 4b; 
     FIG. 6 illustrates a wall outlet and the position of a wall plug adapter received thereon; and 
     FIG. 7 illustrates a wall plug adapter having a flange according to one aspect of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now specifically to the drawings and the illustrated embodiments depicted therein, a particularly advantageous application of the inventive concept is a trouble light 10 which includes a cage comprising a front cover 11 and a back shield 12. Such trouble lights are inexpensive and readily available. Furthermore, many consumers already own a trouble light and can, therefore, utilize the present invention to obtain the numerous benefits of compact fluorescent lamp technology without a large investment. A fluorescent lamp 25 and a socket adaptor 40 are provided within trouble light cage 11 and received in a standard screw socket (not shown) in handle 14. A cord 15 comprising standard 120 volt wiring connects handle 14 with three-prong plug 17. 
     A wall plug adaptor 18 (FIG. 2) includes a three prong plug 20, a housing 21, a three prong receptacle 23, and a cord 24 comprising standard 120 volt wiring connecting the circuitry within housing 21 to the socket 23. Housing 21 contains a ballast for supplying appropriate strike voltages and operating voltages for lamp 25. Such ballast may include an electronic ballast or a conventional core and coil transformer, and a magnetic ballast, which are not shown. The circuitry in housing 21 has a normal power factor for providing power to a fluorescent lamp, and thus provides 57 volts AC and up to 280 milliamps of current for operating the fluorescent lamp 20 (FIG. 2). Additionally, a current of 520 milliamps will be provided initially by the circuitry in housing 21 to start the fluorescent lamp. The circuit components in housing 21 are readily available standard components which are well known in the art, and accordingly will not be described in greater detail herein. 
     Cord 24 is preferably at least six inches long, and may advantageously be provided having even larger lengths. By providing socket 23 on an end of cord 24, housing 21 does not have an aperture located therein, and thus, the housing surface does not include apertures for receiving the connectors of plug 17. This allows housing 21 to fully enclose the circuitry located therein in a simple and relatively inexpensive manner, and permits wall plug adaptor 18 to be used outdoors. Further, cords 24 and 15 (FIG. 1) may be used to secure the electrical connection between trouble light 10 and adapter 18. This may be done by simply tying the cords together, or by utilizing various well known attachments (not shown) for plugs and sockets such as 17 and 23, which will maintain the electrical connection therebetween. By securely mounting housing 21 to the wall outlet 50 (FIG. 6), using a screw 52 extending through a hole 54 (FIG. 7) in a flange 56 on housing 21 and received in the outlet cover screw threads, such arrangement avoids circuit interruption from inadvertent tugs on cord 15. Additionally, the cord 24 (FIG. 2) insures that the socket 23 is spaced at least six inches from circuitry within housing 18. This is important for UL approval as UL will only pass electrical devices having a six inch lead connecting a ballast to other circuitry. 
     The fluorescent lamp 25 (FIG. 3) has a first tube 26 and a second tube 28 carried by a base 29. A first electrical conductor 30 projects from base 29 and makes electrical contact with connector 31 (FIG. 4b) on socket adaptor 35. A similar electrical conductor (not shown) projects from the side of base 29 opposite conductor 30 and is received by an electrical connector 33 on socket adaptor 40. Base 29 includes a projection 35 having four frictional elements 36, 37 and 38 (the fourth frictional element not shown) thereon which provide frictional coupling between base 29 and the adaptor 40 (FIGS. 4a and 4b) when projection 35 is received within a receptacle 39 of socket adaptor 40. Socket adaptor 40 (FIG. 4a) includes threads 42 which are used to screw the socket adaptor into a standard lamp screw socket. A screw 43 is provided to secure the fluorescent lamp within socket adaptor 40. Fluorescent lamp 25 is a double duplex twin tube fluorescent lam which is basically of a conventional design. In the illustrated embodiment, lamp 25 is a 13 watt compact fluorescent lamp marketed by Osram under model number F13DTT/27K. The fluorescent tubes may advantageously be covered with a silicon coating which prevents the glass of the tubes from shattering if the tubes are broken. Such silicone coatings are known in the art and used on light bulbs which are mounted over counter tops or meat counters where it is likely that someone may come into physical contact with the light bulbs causing them to break, and in locations where broken glass would be especially dangerous. 
     Upon assembly fluorescent lamp 25 is received in socket adaptor 40 as shown in FIG. 5 and screw 43 is screwed into projection 3 (FIG. 3) to prevent fluorescent lamp 25 from separating from socket adaptor 40. The bulb and adaptor are then inserted into trouble lamp 10. When lamp plug 17 is plugged into output socket 23, the voltage output from housing 21 will provide power which is compatible with fluorescent lamp 25 received in socket adaptor 40 and screwed into trouble lamp 10. If a user inadvertently plugs the trouble light into a wall outlet without using the converter 18, the fluorescent lamp may cease to operate, but should not explode. 
     Although the invention has been advantageously exemplified with a trouble light, the invention is also useful for indoor lamps such as indoor use in bedrooms and living rooms as well as offices. Thus, changes and modifications in the specifically disclosed embodiments can be carried out without departing from the principles of the invention which is intended to be limited only by the scope of the appended claims, as interpreted according to the principles of patent law including the doctrine of equivalents.