Induction rechargeable electronic candle system

• US 8,210,708 B2
• Filed: 11/18/2008
• Issued: 07/03/2012
• Est. Priority Date: 11/18/2008
• Status: Active Grant

• Current Assignee: L&L Candle Company, LLC
• Original Assignee: Smart Candle LLC
• Inventors: Hau, Daniel, Cowley, Tim, Vail, Shane
• Primary Examiner(s): Negron, Ismael
• Application Number:
  US12/273,337
• Publication Number:
  US 20100124050A1
• Time in Patent Office: 1,323 Days
• Field of Search: 362/183, 362/249.02, 362/184, 362/810, 320/108
• US Class Current: 362/183
• CPC Class Codes: F21L 2/00 Systems of electric lighting devices systems employing both electric and non-electric light sources or exchangeable light sources F21L27/00
• CPC Class Codes: F21L 4/08 characterised by means for in situ recharging of the batteries or cells
• CPC Class Codes: F21S 10/04 simulating flames
• CPC Class Codes: F21S 10/046 by movement of parts, e.g. by movement of reflectors or light sources
• CPC Class Codes: F21S 6/001 being candle-shaped with varying lighting effect of simulating flames F21S10/04; string of light sources F21S4/00
• CPC Class Codes: F21S 9/02 the power supply being a battery or accumulator
• CPC Class Codes: F21V 23/026 Fastening of transformers or ballasts
• CPC Class Codes: F21V 23/04 the elements being switches safety devices F21V25/00
• CPC Class Codes: F21V 3/02 characterised by the shape
• CPC Class Codes: F21W 2121/00 Use or application of lighting devices or systems for decorative purposes, not provided for in codes F21W2102/00 – F21W2107/00
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]
• CPC Class Codes: H05B 45/50 responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
• CPC Class Codes: Y10S 362/81 Imitation candle

Abstract

A large plurality of artificial, battery-operated, electronic candles are arranged to be simultaneously recharged upon placement on a series of interconnected charging trays that include a transformer primary winding at defined locations thereon. The primary windings are driven by an AC signal whose duty cycle is controlled by a pulse width modulator IC to induce a voltage across secondary windings contained within the candle housing. This induced signal is rectified to produce the battery charging current and the delivery of the charging current to the rechargeable batteries is controlled by a microprocessor IC.

Claims

1. An electronic candle system, comprising:

(a) a plurality of artificial candles, each comprising a housing containing an LED light source, a rechargeable DC battery for energizing the LED light source, a transformer secondary winding, an AC to DC converter circuit coupled between the transformer winding and the DC battery, and a first semiconductor switch disposed between the AC to DC converter circuit and the battery; and

(b) a plurality of box-like trays, each having a top surface, a bottom surface and four mutually perpendicular side surfaces defining a hollow interior, a first side surface having a laterally projecting plug member and an opposed side surface having a socket for receiving the plug member of an adjacently positioned tray therein, each said tray supporting a plurality of said artificial candles at defined locations thereon, said plurality of trays including a transformer primary winding proximate each of said defined locations;

(c) means for applying a DC voltage to a string of such trays by having the plug member of one tray inserted into the socket of an adjacent tray and connecting the plug member of a first tray in the string to a DC voltage source; and

(d) a DC to AC converter in each said tray comprising a pulse width modulator connected to receive said DC voltage and producing an AC output to the primary windings, wherein the primary windings have a center tap connected to a DC current source and a pair of outer terminals and further including semiconductor switching means connected between the pair of outer terminals and ground and where the semiconductor switching means are driven by the pulse width modulator, whereby an AC voltage is induced across the secondary winding of candles disposed at said defined locations, said AC to DC converter in each said candles thereby producing a DC current for recharging the DC battery in each such candles.

2. The system of claim 1, wherein the DC current source includes means for limiting the current being collectively drawn by the transformer primary windings to a predetermined maximum value.

3. The system of claim 1, wherein the transformer primary windings at each of the defined locations are disposed about a magnetic core that project vertically from the center of a cylindrical well formed in the tray.

4. The system of claim 3 wherein each of the candles includes a housing having a top surface, a base member and a generally cylindrical side wall, the base member including a hollow sleeve extending perpendicularly and concentrically upward within the housing, the sleeve adapted to receive the magnetic core of a primary winding therein.

5. The system of claim 4 wherein the secondary winding surrounds the hollow sleeve.

6. The system of claim 5 wherein the LED light source projects through an opening in the top surface of the housing.

7. An electronic candle system, comprising:

(a) a plurality of artificial candles, each comprising a housing containing an LED light source, a rechargeable DC battery for energizing the LED light source, a transformer secondary winding, an AC to DC converter circuit coupled between the transformer winding and the DC battery, and a first semiconductor switch disposed between the AC to DC converter circuit and the battery, wherein each of the candles further includes a programmed microprocessor for controlling the conductivity of the first semiconductor switch and further including a second semiconductor switch connected in series with the LED light source across the DC battery, the conductivity of the second semiconductor switch being controlled by the microprocessor; and

(b) a plurality of box-like trays, each having a top surface, a bottom surface and four mutually perpendicular side surfaces defining a hollow interior, a first side surface having a laterally projecting plug member and an opposed side surface having a socket for receiving the plug member of an adjacently positioned tray therein, each said tray supporting a plurality of said artificial candles at defined locations thereon, said plurality of trays including a transformer primary winding proximate each of said defined locations;

(c) means for applying a DC voltage to a string of such trays by having the plug member of one tray inserted into the socket of an adjacent tray and connecting the plug member of a first tray in the string to a DC voltage source;

(d) a DC to AC converter in each said tray connected to receive said DC voltage and producing an AC output to the primary windings whereby an AC voltage is induced across the secondary winding of candles disposed at said defined locations, said AC to DC converter in each said candles thereby producing a DC current for recharging the DC battery in each such candles; and

further including a position sensing transducer disposed within the housing and adapted to provide an input signal to the microprocessor when the candle is in other than an upright position; and

an audible alarm device connected in series with a third semiconductor switch across the battery, the conductivity of the third semiconductor switch being controlled by the microprocessor whereby the alarm device is made to sound if the candle remains in other than an upright position for a predetermined time period.

8. The system of claim 7 and further including a manually operable on/off switch connected to the microprocessor for controlling the mode of operation of the LED light source between one of off, blinking and on steady.

9. The system of claim 7, further including a piezoelectric transducer responsive to a change in air pressure for sending a signal to the microprocessor, the microprocessor being responsive to said signal for turning off the second semiconductor switching means and extinguishing the LED light source.

10. The system of claim 9 wherein the piezoelectric transducer comprises a PVDF film.

11. The system of claim 7, further including a visible indicator controlled by the microprocessor to blink on and off at a programmed rate upon detection that the candle is in other than an upright position.

12. The system as in claim 11 wherein the audible alarm device and the visible indicator once triggered remain active until the candle is returned to a defined location on the charge tray.

13. An electronic candle system, comprising:

(a) a plurality of artificial candles, each comprising a housing containing an LED light source, a rechargeable DC battery for energizing the LED light source, a transformer secondary winding, an AC to DC converter circuit coupled between the transformer winding and the DC battery, and a semiconductor switch disposed between the AC to DC converter circuit and the battery;

(b) a tray having at least one contact and at least one terminal for receiving the contact of an adjacently positioned tray therein for electrically connecting said trays, the tray configured to receive a plurality of said artificial candles at defined locations thereon, wherein the tray includes a transformer primary winding proximate each of said defined locations;

(c) a DC to AC converter comprising a pulse width modulator in the tray connected to receive a DC voltage and producing an AC output to the primary windings, whereby an AC voltage is induced across the secondary winding of candles disposed at said defined locations, said AC to DC converter in each of said candles thereby producing a DC current for recharging the DC battery in each such candles; and

(d) wherein the primary windings have a center tap connected to a DC current source and a pair of outer terminals and further including semiconductor switching means connected between the pair of outer terminals and ground and where the semiconductor switching means are driven by the pulse width modulator.