Abstract:
A rechargeable lamp system includes a set of one or more self-standing rechargeable lighting fixtures (luminaries) removably received on a recharging platter. The luminaries each include a light diffusor resembling a candle that turn on when removed from the charging platter. The luminaries also turn on when power to the charging platter is turned off, which allows the set to be used as a table lamp, and has the added benefit of turning the luminaries on automatically during a power failure. The luminaries are each inductively coupled to the recharging platter, which enables to provide an aesthetically pleasing interface free of electrical contacts.

Description:
This application claim benefit of Provisional Application No. 60/214,095 filed Jun. 26, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention is drawn to the field of illumination, and more particularly, to a novel rechargeable lamp system. 
     BACKGROUND OF THE INVENTION 
     Candles may be moved and placed to provide illumination and/or ambience. While their utilitarian and aesthetic advantages are well-known, candles suffer from an undesirable self-consumption, needing to be replaced when used-up; produce smoke especially when snuffed, which may foul the air; require vigilant attendance to mitigate an ever-present fire hazard; are susceptible to being extinguished by gusts of air when used outdoors or moved around; and may give rise to undesirable wax build-up, which in many instances needs removed from candle support members or underlying structures. 
     There is thus a need to provide a rechargeable lamp system that enjoys the many utilitarian and aesthetic advantages of candles but is not subject to their disadvantages. 
     SUMMARY OF THE INVENTION 
     It is accordingly a general object of the present invention to disclose a rechargeable lamp system that provides candle-like lighting for indoor or outdoor use that avoids the problems associated with candles. 
     In accordance therewith, the rechargeable lamp system of the present invention includes a recharging platter adapted to receive a set of luminaries including a first circuit coupled to each luminary of said set of luminaries received thereon operative in response to supplied AC power to provide a charge signal to each luminary of said set of luminaries received thereon; and a set of luminaries each having a light emitting element connected to a rechargeable battery pack via a second circuit operative in one mode to charge said rechargeable battery pack in response to said charge signal when each luminary of said set of luminaries is received on said recharging platter and operative in another mode to activate said light emitting element in response to the absence of said signal, whereby, each said luminary lights if removed from said recharging platter and lights if no AC power is supplied to said recharging platter when received therein. 
     In the presently preferred embodiments, the set of luminaries includes one or more luminaries each of which is inductively coupled to the first circuit of the recharging platter. The inductive coupling provides automatic, hands-free recharging of the rechargeable battery pack of a luminary upon its receipt by the recharging platter, and provides automatic, hands-free actuation of a luminary when it is removed therefrom. 
     In the presently preferred embodiments, each luminary of the set of luminaries is self-standing and includes a diffusor that may be shaped to resemble a candle releasably mounted to a base member supporting said light emitting element therewithin. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other objects, advantageous features and inventive aspects of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description of the preferred embodiments when considered in connection with the accompanying drawings, in which: 
     FIG. 1 is a perspective view of an exemplary embodiment of the present invention, showing a charging stand and one lamp module; 
     FIG. 2 is a top view of the charging stand; 
     FIG. 3 is a front view of the charging stand; 
     FIG. 4 is a bottom view of the charging stand; 
     FIG. 5 is a sectional view of the charging stand, taken along line  5 — 5  of FIG. 2; 
     FIG. 6 is a sectional view of the charging stand, taken along line  6 — 6  of FIG. 2; 
     FIG. 7 is a circuit diagram of the charging stand circuit; 
     FIG. 8 is an exploded perspective view of an exemplary embodiment of a lamp module according to the present invention; 
     FIG. 9 is a front view of the lamp module; 
     FIG. 10 is a right side view of the lamp module; 
     FIG. 11 is a top view of the lamp module; 
     FIG. 12 is a bottom view of the lamp module; 
     FIG. 13 is a sectional view of the lamp module taken along line  13 — 13  of FIG. 9; 
     FIG. 14 is a sectional view of the lamp module taken along line  14 — 14  of FIG.  10 . 
     FIG. 15 is a sectional view of the lamp module taken along line  15 — 15  of FIG. 9; and 
     FIG. 16 is an exemplary embodiment of a circuit diagram of the lamp module circuit board according to the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIG. 1, reference numeral  10  generally refers to the rechargeable lamp system of the present invention. Lamp system  10  comprises a charging stand  12  and a plurality of lamp modules  110 ,  111 ,  112  and  114 . 
     As shown in FIGS. 1 and 2, stand  12  comprises slots  16 ,  18 ,  20  and  22  which are each adapted to removably receive one of said lamp modules  110 ,  111 ,  112  and  114 . Slots  16 ,  18 ,  20  and  22  each include a respective cylindrical wall  38 ,  40 ,  42 , and  44  and a substantially planar floor  46 ,  48 ,  50  and  52 . 
     A power cord  24  having an inline power switch  26  and a “wall-block” style transformer provides power to charging stand  12  via ordinary 120-volt household current. In alternate embodiments, the transformer may be dispensed with. 
     As will be described in greater detail herein, each of modules  110 ,  111 ,  112  and  114  is battery-powered and designed to be charged by magnetic induction when placed in a respective one of slots  16 ,  18 ,  20  and  22 . Modules  110 ,  111 ,  112  and  114  are each designed to illuminate when removed from slots  16 ,  18 ,  20  and  22 , or when AC power is cut off to charging stand  12 . 
     The number of lamp modules (and a corresponding slot for each module) shown in the preferred embodiment is intended to be merely exemplary. It should be understood that the lamp system  10  of the present invention may be constructed with any number of modules. 
     Referring now to FIGS. 3-4, stand  12  also includes an upper portion  30  and a lower portion  32 . In an exemplary embodiment, upper portion  30  is ceramic. However, upper portion  30  may be made from other suitable materials, such as wood or plastic. In the interest of economy, lower portion  32  in the exemplary embodiment is formed of injection-molded plastic, but may as well be made of other suitable materials, such as steel or other metal or other material. In the exemplary embodiment, upper portion  30  and lower portion  32  snap together. However, any suitable means, such as bonding, screws, etc. could be used to secure upper portion  30  and lower portion  32 . 
     As shown in FIGS. 2,  5  and  6 , stand  12  further includes a circuit board  58  which is hard-wired to cord  24  and four primary induction coils (wired in parallel), one coil encircling each of walls  38 ,  40 ,  42  and  44 , respectively. FIG. 5 shows a pair of primary induction coils  54  and  56  that encircle walls  44  and  42 , respectively. Identical primary coils (not shown) encircle walls  38  and  40 . 
     FIG. 7 shows the circuit formed by transformer  28 , inline power switch  26 , and primary induction coil  54 . As shown in FIG. 7, transformer  28  converts 120 volts AC to 12 volts AC. The three other primary induction coils, not shown, are preferably wired in parallel with primary induction coil  54 . In other embodiments, the transformer component can be replaced by the inductor coils (on the platter and luminaries), whose turn-ratios are selected to provide a stepped-down voltage to the lamps. As will be appreciated by those of skill in the art, an oscillator providing frequencies higher than line frequency may be employed to improve efficiency (inductor size and attendant cost). 
     Modules  110 ,  111  and  112  are identical to module  114 . Thus, it will only be necessary to describe module  114  in detail. 
     As shown in FIGS. 8-16, module  114  comprises a diffuser  116 , a light bulb  118 , a battery pack  120 , a circuit board  122 , a secondary induction coil  124  and a base  126 . 
     Diffuser  116  in the exemplary embodiment is formed of blow-molded plastic (or glass) having a frosted outer surface  142 . It could also be injection-molded plastic with a frosted, translucent finish. In the exemplary embodiment, diffuser  116  is slender and elongated in shape and includes a mid-section  146  that tapers upwardly to a tip  144  and tapers slightly to a tail  148 . This shape is chosen to provide optimal light color and transmission, as well as even diffusion of light from bulb  118 . Obviously, numerous alternative shapes for diffuser  116  are possible. However, the internal volume created by diffuser  116  must be sufficient to envelop bulb  118 , battery pack  120  and circuit board  122 . In addition, because of the heat generated by bulb  118 , it is desirable to provide air space between bulb  118  and diffuser  116  to prevent diffuser  118  from melting or deforming. 
     Base  126  comprises a lower portion  128  that provides stable support for module  114  when placed on a level surface or within slot  16 . Neck  130  is adapted to removably receive diffuser  116  (to enable access to bulb  118  and battery pack  120 ). Neck  130  includes tabs  134 ,  136 ,  138  and  140  and a lip  135  that cooperate to secure tail  148  of module  114  to neck  130  (see FIGS. 8,  13  and  14 ). 
     Battery pack  120  in the exemplary embodiment comprises three “AA” Nickel-Cadmium (Ni-Cad) cells wrapped in PVC shrink-wrap and having a total output of 3.6Vdc and 500-800 mA. Of course, other types and sizes of rechargeable cells, such as Nickel-Metal-Hydride or Lithium cells, could be substituted for the Ni-Cad cells. Such cells would provide more power, and charge more quickly than Ni-Cads, but are substantially more expensive. 
     The power requirements for bulb  118  are, of course, chosen to match the power output of battery pack  120 . In the exemplary embodiment, bulb  118  is a conventional miniature incandescent bulb, such as Chicago Miniature Lamp, Inc. part # CM1738, having an output of 1 candela and having design power requirements of 2.80V and 60 mA and an expected life of 6,000 hours. Of course, other lamps and types of light sources, such as a light-emitting diode (L.E.D.) may be substituted for bulb  118 . The incandescent bulb shown is preferred because of its balance of cost, heat generation, power consumption, expected service life and brightness characteristics. 
     As shown in FIGS. 13 and 14, bulb  118  and battery pack  120  are preferably hard-wired to circuit board  122 . As shown in FIG. 16, circuit board  122  comprises four primary circuits that control the charging of battery pack  120  and the lighting of bulb  118 . 
     A charging circuit  150  regulates the voltage and current flowing to battery pack  120  from secondary induction coil  124  to prevent damage to battery pack  120 . A latch circuit  154  cuts off current to bulb  118  when the voltage output of battery pack  120  drops below 3.1 volts, thus preventing damage to battery pack  120  which could be caused by fully draining battery pack  120 . A charge-sensing switch  156  works in cooperation with latch circuit  154  to turn off current to bulb  118  when current is detected in charging circuit  150 . A constant current source circuit  152  provides a constant flow of current (65 mA in the exemplary embodiment) to bulb  118 . This enables bulb  118  to shine at a constant brightness despite fluctuations in the output current from battery pack  120 . In alternate embodiments, a constant voltage source could be employed. 
     As described above, battery pack  120  is charged by magnetic induction. The magnetic field created by primary induction coil  54  (when current is applied) induces a current in secondary induction coil  124  when secondary induction coil  124  is concentrically located relative to primary induction coil  54 . In the present invention, this occurs when module  114  is placed within slot  16  (see FIG.  1 ). 
     It is preferable to ship battery pack  120  fully charged, as this will increase the shelf life of the Ni-Cad cells. However, shipping battery pack  120  fully charged requires the inclusion of means for electrically isolating battery pack  120  from lamp  118  between the time battery pack  120  is charged and when module  114  is first used by an end consumer. Such means could comprise a Mylar tab (not shown) inserted between two electrical contacts after the initial charging which would be removed by the consumer before first use. Alternatively, such means could comprise a fusible link (not shown). The fusible link would be adapted to close current regulating circuit  152  when current is sensed in charging circuit  150  (i.e., the first time the consumer plugs in charging stand  12 ). 
     Operation of lamp system  10  is elegantly straightforward. As described above, bulb  118  is designed to illuminate when no current is sensed in charging circuit  150 . Thus, bulb  118  will automatically turn on when module  114  is removed from slot  16 . Charging stand  12  and module  114  can also function as a table lamp by leaving module  114  in slot  16  and switching off inline power switch  26 . Module  114  also functions as an emergency light—automatically turning on during a power failure. 
     The present invention in its broader aspects is not limited to the described embodiments, and departures may be made therefrom without departing from the principles of the invention and without sacrificing its primary advantages. Obviously, numerous modifications may be made to the present invention. Thus, the invention may be practiced otherwise than as specifically described herein.