Annunciator apparatus for monitoring electrical connections

• US 5,434,558 A
• Filed: 01/21/1993
• Issued: 07/18/1995
• Est. Priority Date: 07/05/1991
• Status: Expired due to Fees

• Current Assignee: Stajer Corporation
• Original Assignee: Stajer Corporation
• Inventors: Zeder, Abraham
• Primary Examiner(s): Peng, John K.
• Assistant Examiner(s): Pope, Daryl C.
• Application Number:
  US08/006,874
• Time in Patent Office: 908 Days
• Field of Search: 340/568, 340/644, 340/310 CP, 340/687, 200/51.1
• US Class Current: 340/568.3
• CPC Class Codes: G08B 13/1409 for removal detection of electrical appliances by detecting their physical disconnection from an electrical system, e.g. using a switch incorporated in the plug connector

Abstract

An annunciator for indicating the removal of an electrical plug from the electrical receptacle. The electrical receptacle includes neutral switching contacts actuated in response to the insertion of a plug into the receptacle. An input circuit in the annunciator apparatus monitors the state of the neutral switching contacts and couples signals produced when a plug is removed to a latching circuit thereby to produce an audible or electrical indication of plug removal. The input Circuit and latching circuit are electrically isolated, and the annunciator detects any attempts to disconnect the apparatus from an external power supply or to remove any internal battery.

Claims

1. In an apparatus for detecting the unauthorized removal of an electrical plug with male contacts wherein said apparatus includes receptacle means with power, neutral and ground terminal means for connection to power, neutral and ground conductors and for receiving the male contacts of the plug and neutral switching means connected to said neutral terminal means for responding to the insertion of the plug into said receptacle means by closing and wherein said apparatus includes annunciator circuit means for indicating the unauthorized removal of the electrical plug from said receptacle meant including input circuit means for producing a transition sensed signal in response to the opening of said neutral switching means when said plug is removed and indicating circuit means for continuously announcing removal of the electrical plug in response to the transition sensed signal, the improvement comprising:

A. first power supply means connected to the power and neutral conductors for producing a neutral-reference supply voltage for energizing said input circuit means,

B. second power supply means connected to the power, neutral and ground conductors for producing a ground-reference supply voltage for energizing said indicating circuit means, and

C. isolating signal transfer means for energizing said indicating circuit means in response to the transition sensed signal.

2. Apparatus as recited in claim 1 wherein said input circuit means includes signal processing means for generating the transition sensed signal and said indicating circuit means includes alarm generator means for producing a continuous announcement and signal processing means for energizing the alarm generator means and wherein each of said first and second power supply means includes corresponding generating means for generating a power supply voltage for energizing the signal processing means in the input circuit means and indicating means respectively.

3. Apparatus as recited in claim 2 wherein each of first and second power supply means includes battery means in parallel with said corresponding generating means for providing backup power in the absence of electrical power from the power, neutral and ground conductors.

4. Apparatus as recited in claim 3 wherein said battery means is removable and each of said first and second power supply means includes battery monitoring means connected to the corresponding battery means and signal processing means in said input circuit means and said indicating circuit means, respectively, for energizing said respective signal processing means when said battery means is removed thereby to energize said alarm generator means.

5. Apparatus as recited in claim 3 wherein each of said battery means in said first and second power supply means includes a rechargeable battery and means for connecting to said battery thereby to enable said respective power supply means to charge said battery when the power, neutral and ground conductors are energized.

6. Apparatus as recited in claim 2 additionally comprising plug connection means for interconnecting said first and second power supply means to corresponding ones of the power, neutral and ground conductors and unidirectional conducting means connected between said ground reference power supply and said neutral reference power supply and connected to said signal processing means in said indicating circuit means for energizing said alarm generator means when said plug connection means disconnects from the power, neutral and ground conductors.

7. Apparatus as recited in claim 6 wherein each of said first and second power supply means includes battery means in parallel with said corresponding generating means for providing backup power in the absence of electrical power from the corresponding ones of the power, neutral and ground conductors, each said battery means including a rechargeable battery and means for connecting to said battery thereby to enable said respective power supply means to charge said battery when the power, neutral and ground conductors are energized.

8. Apparatus as recited in claim 7 wherein said battery means is removable and each of said first and second power supply means includes battery monitoring means connected to the corresponding battery means and signal processing means in said input circuit means and said indicating circuit means, respectively, for energizing said respective signal processing means when said battery means is removed thereby to energize said alarm generator means.

9. Apparatus as recited in claim 2 additionally including reset switching means connected to second power supply means and said signal processing means in said indicating means operable for deenergizing said alarm generator means.

10. Apparatus as recited in claim 1 wherein said isolating signal transfer means comprises electro-optical isolating means including a light generator means and light-responsive switching means and wherein said signal processing means in said input circuit means includes transition sensed signal switching means in series with said light generator means for controlling the operation of said light generator means in response to the transition sensed signal and said signal processing means in said indicating circuit means includes latching means for energizing said alarm generator means and means connecting said light-responsive switching means to said latching means for causing said latching means to energize said alarm generator means in response to the transition sensed signal.

11. Apparatus as recited in claim 10 wherein light generator means and said transition sensed signal switching means connect across said first power supply means and said transition sensed signal switching means comprises transistor switching circuit means for interconnecting said light generator and said neutral conductor.

12. Apparatus as recited in claim 11 wherein said input circuit means includes signal processing means for generating the transition sensed signal and said indicating circuit means includes alarm generator means for producing a continuous announcement and signal processing means for energizing the alarm generator means and wherein each of said first and second power supply means includes corresponding generating means for generating a power supply voltage for energizing the signal processing means in the input circuit means and indicating circuit means respectively.

13. Apparatus as recited in claim 12 wherein each of first and second power supply means includes battery means in parallel with said corresponding generating means for providing backup power in the absence of electrical power from the power, neutral and ground conductors.

14. Apparatus as recited in claim 13 wherein said battery means is removable and each of said first and second power supply means includes battery monitoring means connected to the corresponding battery means and signal processing means in said input circuit means and said indicating circuit means, respectively, for energizing said respective signal processing means when said battery means is removed thereby to energize said alarm generator means.

15. Apparatus as recited in claim 13 wherein each of said battery means in said first and second power supply means includes a rechargeable battery and means for connecting to said battery thereby to enable said respective power supply means to charge said battery when the power, neutral and ground conductors are energized.

16. Apparatus as recited in claim 12 additionally comprising plug connection means for interconnecting said first and second power supply means to the corresponding ones of the power, neutral and ground conductors and unidirectional conducting means connected between said ground reference power supply and said neutral reference power supply and connected to said signal processing means in said indicating circuit means for energizing said alarm generator means when said plug connection means disconnects from the power, neutral and ground conductors.

17. Apparatus as recited in claim 16 wherein each of said first and second power supply means includes battery means in parallel with said corresponding generating means for providing backup power in the absence of electrical power from the corresponding ones of the power, neutral and ground conductors, each said battery means including a rechargeable battery and means for connecting to said battery thereby to enable said respective power supply means to charge said battery when the power, neutral and ground conductors are energized.

18. Apparatus as recited in claim 17 wherein said battery means is removable and each of said first and second power supply means includes battery monitoring means connected to the corresponding battery means and signal processing means in said input circuit means and said indicating circuit means, respectively, for energizing said respective signal processing means when said battery means is removed thereby to energize said alarm generator means.

19. Apparatus as recited in claim 12 additionally including reset switching means connected to said second power supply means and said signal processing means in said indicating means operable for deenergizing said alarm generator means.

20. In an apparatus for detecting the unauthorized removal of an electrical plug wherein said apparatus includes receptacle means with power, neutral and ground terminal means for connection to power, neutral and ground conductors and for receiving the male contacts of the plug and neutral switching means connected to said neutral terminal means for responding to the insertion of the plug into said receptacle means by closing and wherein said apparatus includes annunciator circuit means for indicating the unauthorized removal of the electrical plug from said receptacle means including input circuit means for producing a transition sensed signal in response to the opening of said neutral switching means when a plug is removed and indicating circuit means for continuously announcing removal of the electrical plug in response to the transition sensed signal, the improvement comprising:

A. first power supply means connectible to the power, and neutral conductors for producing a neutral-reference supply voltage for energizing said input circuit means,

B. second power supply means connectible to said power, neutral and ground conductors for producing a ground-reference supply voltage for energizing said indicating circuit means,

C. plug connection means for releasably connecting said first and second power supply means to the respective ones of the power, neutral and ground conductors, and

D. unidirectional conducting means connected between said ground reference power supply and said neutral reference power supply and connected to said indicating circuit means thereby to initiate a continuous announcing by the indicating circuit means when said plug connection means disconnects from the power, neutral and ground conductors.

21. Apparatus as recited in claim 20 wherein said unidirectional conducting means includes a diode and resistor connected to conduct current to the neutral conductor in said first power supply means and connected to said signal processing circuit in said indicating circuit means and to said second power supply for causing said signal processing circuit to energize said alarm generator means when said plug connection means disconnects from the neutral and ground conductors.

22. Apparatus as recited in claim 20 additionally including reset switching means connected to said signal processing means in said indicating means operable for deenergizing said alarm generator.

23. In an apparatus for detecting the unauthorized removal of an electrical plug wherein said apparatus includes receptacle means with power, neutral and ground terminal means for connection to power, neutral and ground conductors and for receiving the male contacts of the plug and neutral switching means connected to said neutral terminal means for responding to the insertion of the plug into said receptacle means by closing and wherein said apparatus includes annunciator circuit means for indicating the unauthorized removal of the electrical plug from said receptacle means including input circuit means for producing a transition sensed signal in response to the opening of said neutral switching means when a plug is removed and indicating circuit means for continuously announcing removal of the electrical plug in response to the transition sensed signal, the improvement comprising:

A. first power supply means connected to said power and neutral conductors for producing a neutral-reference supply voltage for energizing said input circuit means,

B. second power supply means connected to said power, neutral and ground conductors for producing a ground-reference supply voltage for energizing said indicating circuit means, and

C. independent battery backup means in each of said first and second power supply means for energizing said input circuit means and said indicating circuit means when the power, neutral and ground conductors are deenergized whereby said backup battery means in said first and second power supplies produce voltages with respect to the neutral conductor and the ground conductor respectively.

24. Apparatus as recited in claim 23 wherein said battery means is removable and each of said first and second power supply means includes battery monitoring means connected to the corresponding battery means and signal processing means in said input circuit means and said indicating circuit means, respectively, for energizing said respective signal processing means when said battery means is removed thereby to energize said alarm generator means.

25. Apparatus as recited in claim 24 wherein each of said battery means in said first and second power supply means includes a rechargeable battery and means for connecting to said battery thereby to enable said respective power supply means to charge said battery when the corresponding ones of the power, neutral and ground conductors are energized.

26. Apparatus as recited in claim 24 additionally including reset switching means connected to said second power supply means and said signal processing means in said indicating means operable for deenergizing said alarm generator.