MXPA00011349A - Switch cover plate providing automatic emergency lighting. - Google Patents

Abstract

A wall mounted cover plate (40) conceals an electrical circuit (50) capable of sensing the field provided by a covered switch (30) or electrical socket circuit. When power is lost at the wall circuit the electrical circuit (50) senses the loss of power and activates one or more LEDs (90A) to provide emergency illumination. The electrical circuit (50) is self contained and does not require stand-by energy so that the batteries (58) are long lasting.

Description

SWITCH COVER PLATE THAT PROVIDES AUTOMATIC EMERGENCY LIGHTING BACKGROUND OF THE INVENTION FIELD OF THE INVENTION: This invention relates generally to emergency light devices such as auxiliary automatic lamps, and more particularly to an emergency light device mounted on a common switch cover plate and which provides a • source of illumination and a detector to determine when 'the alternating current (AC) power has been lost from the electrical switch covered by the plate. 15 DESCRIPTION OF THE RELATED ART: The following technique defines the present state of this field: US Patent No. 4,177,500 of * Nicholl et al., Describes a failure light of 20 energy to monitor a power line and for power interruption lighting. This invention includes a light bulb, a rechargeable battery, a power supply that provides the charging current for the battery, a pair of diodes that 25 connect the battery through the power supply, Ref. 124757 a pair of cascade transistors that connect the bulb to the battery with the base emitter junctions. US Pat. No. 4,461,974 to Chiu discloses a multiple lamp system for use with a fiber optic light guide to automatically interconnect from a main lamp to the auxiliary lamp, at the failure of the previous one. A solenoid is used with the inductor in the main lamp circuit to overcome the deviation of the switch in the auxiliary lamp circuit to keep the first one open. When the main lamp fails causing the interruption of current flow, the switch is closed which allows the auxiliary lamp to be energized. An indicator is provided to show which lamp is working. US Pat. No. 4,514,789 to Jester, discloses a light switch plate having a rearwardly open housing for removably supporting an AA battery. This invention is separately mounted on a conventional wall mounted on a 110 volt AC light switch. An electroluminescent diode (LED) mounted on the front of the housing connects to the battery at through an integrated circuit oscillator, which turns on the LED. US Pat. No. 4,631,649 to McCue et al. Describes an emergency light installation that is permanently mounted in the energy outlet box that has, in fixed relation, a threaded hole for coupling a screw to one face of the plate and slots for coupling an electrical contact. The emergency electrical installation includes a housing, an electrical contact extending from the rear of the housing, a battery, a battery charger, and a lamp mounted in the housing and wired to provide illumination during an energy shutdown. U.S. Patent No. 4,977,351 of Bavaro et al. Describes an emergency light system that allows, in at least one gas discharge lamp, to be operated from an Alternating Current or AC power source when the AC is present and forms a battery when the signal is not present. AC. The circuit also provides the ability to turn on the lamp under other selected emergency conditions such as in response to the detection of an intruder, or in response to the detection of smoke, heat, water, or some other emergency.

U.S. Patent No. 5,132,596 to Alters et al. Describes an exterior lighting control that includes a photodetector sensitive to outdoor light and an alternating current relay with a pair of movable contacts between rest and execution positions. The relay includes an arrangement that activates the contact that responds to the photodetector and the alternating current that diverts the contact in an execution position and moves the contacts electromagnetically to a resting position. The arrangement that drives the contact is sufficiently firm and sensitive to alternating current to limit the vibration in the contact during the execution step to rest of fifteen milliseconds when the photodetector detects a transition between darkness and daylight. Preferably, the vibration is limited between 1 and 10 milliseconds. US Patent No. 5,336,977 to Li discloses an emergency light device that includes a recessed cover, a magnetic field detection unit, a lamp unit and an actuator unit. The cover is positioned adjacent to an electrical outlet. The magnetic field detection unit is placed inside the cover and detects the absence of a magnetic field from the socket electric current. The lamp unit is operatively mounted - on the cover. The actuator unit is placed inside the cover and electrically connected ^^ to the lamp unit and the detection unit. The actuator unit includes a light sensitive switch unit in response to the detection unit for activating the lamp unit only when the magnetic field of the outlet is absent and there is a very weak light around. ^) U.S. Patent No. 5,473,517 of Blackman, describes a housing for an emergency light source, which is electrically connected to a conventional light switch. The housing replaces a conventional switch plate and they have 15 at least one opening for receiving the switch plate and has at least one opening for receiving the switch actuator of the light switch. The replacement housing includes the wires for the electrical connection to the light switch and is 20 divided into the upper and lower housing section, wherein the upper section includes a battery compartment, a printed circuit board compartment, and an opening for receiving the switch actuator. The lower section of the housing it includes a compartment to receive a compact fluorescent lamp, reflectors, and a diffuser lid. The prior art shows a variety of emergency and safety light devices. Blackman shows the replacement switch plate with the wired connection to a light switch. This switch plate contains a lighting medium. Walters shows a lighting control that has the sensitive medium photodetector. Jester shows a switch plate on. Li shows a magnetic field detector sensitive to the absence of energy in a nearby AC outlet, this detector is unable to operate in conjunction with a switch since without the current flow a magnetic field is not produced. However, the prior art does not show a switch plate of compact size and proportions having the ability to detect a magnetic field to avoid the need for a rugged electrical installation and or to provide an illumination and output marker. The present invention meets these needs and further provides related advantages as indicated in the following brief description.

BRIEF DESCRIPTION OF THE INVENTION The present invention shows certain benefits in construction and use that give rise to the objectives described below. The present invention provides a wall mounted plate that includes an electrical circuit capable of detecting the electrostatic field associated with an electrical circuit inside, or behind, the wall. The electrical circuit uses an antenna to detect the loss of field energy and therefore enable a lighting circuit to provide emergency exit lighting. A main objective of the present invention is to provide a proximity circuit capable of providing an emergency light when a power failure occurs, this circuit has advantages not shown by the prior art. Another objective is to provide a circuit inside a switch plate that is mounted on a switch box by the automatic conditioning method during the power failure. In addition, yet another objective is to provide a compact and relatively flat wall plate to give the appearance of a power take-off cover. ordinary alternating current, which still provides the advantages of emergency light and automatic operation during power failure. Still another object is to provide a compact and relatively flat wall plate to provide the appearance of an ordinary AC socket cover, which still provides the advantages of emergency light and automatic operation during power failure. Still another objective is to provide a compact and relatively flat wall plate to provide the appearance of an ordinary wall cover plate, which still provides the advantages of emergency light and automatic operation during power failure. Other advantages and features of the present invention will be apparent from the following detailed description, taking into account the accompanying drawings, which illustrate, by way of example, the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings illustrate the present invention. Where: Figure 1 is a front elevational view of a cover plate of the wall switch of a first embodiment of the present invention; Figure 2 is a side elevational view, sectioned thereof taken along section line 2-2 in Figure 1 and showing a switch box and a wall switch; Figure 3 is a block diagram of an electrical circuit of the invention; Figure 4 - is a perspective view of the # modality of Figure 1; and Figure 5 is a perspective view of an AC power socket cover plate. DETAILED DESCRIPTION OF THE INVENTION The figures of the drawings described above illustrate the invention of a device for »Emergency light that generates lighting in spaces 20 closed when an energy fault occurs. Illustrated in Figures 1-4 of a first embodiment of the invention is an emergency light device for covering an electrical box of the wall switch 10, which is mounted on or behind a wall 20. The box 25 electric 10 contains an electric wall switch 30 having an externally extending switch arm 32 dislodges the wall 20 to manually adjust to turn the light of a room on and off. The invention includes a switch plate 40, which is a version of the one illustrated in Figures 1, 2 and 4, to cover the electrical box of the wall switch 10, the switch plate provides a surface 42 that mounts the electrical circuit, a means 44 that mounts the plate of switch 44, typically a pair of independently spaced holes, and a coupling means of switch arm 46, typically a rectangular hole. Preferably, the switch plate 40 provides a central portion 40A including the mounting means of the switch plate 44 and the coupling means of the switch arm 46. The central portion 40A is preferably flat, to remain in contact with the surface of wall. The switch plate 40 further includes a peripheral portion 40B which provides a closing means 40C for coupling an electrical circuit 50. The closure means 40C provides a space for containing the components of the electrical circuit 50. This space is closed between the wall 20 and the switch plate 40 so that the Electrical circuit components and their support elements are not visible from the front of the switch plate 40. The central portion 40A cooperates with. the. switch wall 30, and peripheral portion 40B cooperates with the central portion and the wall surrounding the closure of electrical circuit 50. This is considered an important inventive aspect of the present invention wherein the device, taken as a whole, takes on the appearance of a cover of common switch, and provides, a portion near the wall (40A) for coupling the switch arm 32 (also usually referred to as a "lever" or "bolt"), and a peripheral closing portion (40B) that provides a means for housing the circuit within the electrostatic field of the wall switch, or as described below, any other electrical device that generates an electrostatic field. The electrical circuit 50 is illustrated in Figure 3. In this circuit, an antenna 80 is exposed to the local electrostatic field produced by the supporting AC wiring or other means generating the electrostatic field such as the wall switch 30. combination of the strength of the electrostatic field, the coupling capability created by the antenna 80, and the output impedance of an amplifier 82 determines the signal voltage level developed by antenna 80. U.L. security requirements. they require that two resistors of higher safety estimate 84 be inserted in series with the antenna 80 to limit the current flow that must occur in an electrical short between the antenna 80 and the supporting AC power cable. Since, in the present invention there is no way for these two elements to come into contact, this event is unlikely to occur. The amplifier 80 helps the detected signal voltage to drive a maximum detector circuit 86 and a logic control circuit 88 as shown in Figure 3. The maximum detector circuit 86 produces a Direct Current (DC) voltage that is proportional to the voltage amplified antenna once it exceeds a first threshold. Thereafter, the maximum detector circuit 86 saturates a second threshold, without providing any additional assistance to the DC voltage even though the strength of the AC field can be further increased. The characteristics of the fast charge and the slow discharge are appropriately selected to avoid the false activation of a bank of LEDs 90 and any unnecessary delay in the operation. The logic control circuit 88 accepts the inputs of both the maximum detector circuit 86 and a means to reset / test 87, also described as a button. Both inputs are conditioned in the logic control circuit 88 by the schmiddt triggers to produce clear logical transitions. The control logic circuit 88 makes the decisions if the LEDs 90 will be turned on or off depending on the following conditions, where it will be understood that the AC power is considered equivalent in the presence of the electrostatic field described above and that the The loss of AC power is equivalent to the loss of the electrostatic field: 1) With the AC power present with sufficient field strength, the LEDs 90 will be maintained. The momentary activation of the reset button 15 test 87 in turn will momentarily activate the LEDs 90. When the reset / test button 87 is released, the LEDs 90 automatically turn off to prevent accidental and unnecessary discharge of a battery 58 (see Figure 2). 20 2) With the AC power suddenly fading, the LEDs 90 will be secured in a state until one of three things happens: a) The battery 58 is discharged at an unusable level. 25 b) The AC power is restored. c) The test / reset button 87 is momentarily depressed to reset the LEDs 90 to an on state. The subsequent cycle of the test / reset button 87 with the AC power not present will cause the alternating assurance of "ON" and the "OFF" assurance of the LEDs 90. An LED driver circuit 89 detects the logic level produced by the control logic circuit 88 and provides sufficient current to drive the LEDs 90 when it is commanded to do so. The LEDs 90 are preferably of the super-high flow type which can provide adequate lighting in a small room during AC power emergency conditions to facilitate staff orientation. The test / reset means 87 and the control logic circuit 88 are adapted to automatically place the invention in an active state following the loss of the electrostatic field of the medium that generates the electrostatic field (wall switch, etc.) and a closure manual of the illumination means 56, such that a subsequent return of the electrostatic field and a subsequent second loss of the electrostatic field provide an additional ignition of the illumination means 56 without human intervention.

A low-battery test circuit 92 is detected when the battery 58 is discharged below a level that is necessary to provide the illumination of the battery. • emergency maintained. One of the LEDs 90A 5 is lit with a cycle pulse that must be repeatedly lowered to provide a visual warning. The low-battery test circuit 92 is designed to test the battery 58 while the battery current is minimized by depleting during the test. A circuit OR pulse generator 94 operates in a cycle that is very low providing the battery power to a comparator circuit 96. The comparator circuit 96 and a voltage reference circuit 98 are momentarily rotated during each cycle of the pulse generator circuit 94 15 A sample of the battery voltage is compared to the voltage reference of the voltage reference circuit 98. The comparator circuit 96 then momentarily turns on the LED actuator 89B if the voltage of the tested battery is too low. Should The description of operation of each of the individual elements of the circuit described above will be clear, where one skilled in the electrical engineering art will know how to construct and operate each of these elements of the circuit. The purpose 25 of the description of the previous circuit and Figure 3 is only to make the present invention possible and to identify how well-known elements can be assembled and interconnected to produce a working device capable of achieving the objectives of the present invention. The switch plate 40 further provides a means for verifying the lighting means 48. The means for checking the lighting means 48 can include at least one opening 48A in the switch plate 40., the aperture (s) 48A is positioned and coupled with the illumination means 56 to direct the verification of the illumination means 56. Therefore, as shown in Fig. 1, the aperture 48A is one or more rectangular holes in the aperture. the switch plate 40 through which the elements of the lighting means 56 may protrude or be visible. Alternatively, the verification means the lighting means 48 can include at least a portion that transmits light 48B on the switch plate 40, where at least a light transmitting portion 48B is placed and coupled with at least one element of the light. illumination means 56 for indirect verification of the illumination means 56, that is, by viewing the light from the illumination means 56 without checking the illumination means 56 thereof. The means of Alternative check 48B can be a plate color portion of switch 40 which, as shown in Figure 1 can be placed on a part of the illumination element of lighting means 56. In a second embodiment of the invention, as shown in Figure 6, the electrical appliance covered by the switch plate is an electrical outlet means such as a double plug of the type well known in most houses (not shown). The device has an electrical access plug means of the invention. In this case the coupling means of the electrical box is an electric plug means 70, such as the double pins shown in the figure, for coupling the electrical plug means of the electrical appliance. Therefore in this embodiment, the invention is mounted on a wall outlet box and is in close proximity to it. Furthermore, the invention, in this embodiment, provides a plug 72 for accepting the plugs which, on the other hand, would be inserted in the socket of the electrical outlet means. This embodiment shows that the present invention can be used with an electrical socket outlet as well as a wall switch for the same convenient purpose. Obviously, the present invention can be applied to other applications together with the wall switches and AC outlets. Any situation where an AC voltage change occurs, with or without current flow, within a few centimeters of the surface of a wall is appropriate for the mounting of the present invention on the exterior wall surface to indicate that the voltage AC is already present and to provide emergency lighting. An important application is inside the elevators to provide the emergency light in case of a power failure. It is clear that in various applications of the present invention, the non-electrical or physical interconnection between the invention and the AC or wiring device that is monitored by the invention is necessary. In these cases, the closure means 40 can be a uniform plate with the mounting means. The mounting means can be an adhesive support or a magnet or other possible well-known means. Although the invention has been described with reference to at least one preferred embodiment, it will be clearly understood by those skilled in the art that the invention is not limited thereto. Rather, the scope of the invention will be interpreted in conjunction with the appended claims.

It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is the conventional one for the manufacture of the objects or products to which it refers. Having described the invention as above, the contents of the following are claimed as properties:

Claims (15)

1. An emergency lighting device ^ F to be placed on an adjacent wall in a field 5 electrostatic of a medium that generates an electrostatic field, the device is characterized in that it comprises: a wall plate adapted to be mounted on the wall in proximity to the medium that generates the electrostatic field JO, the wall plate includes an electrical circuit means; The electric circuit means comprises a means which detects the variant electrostatic field, an emergency interconnection means, a means of 15 lighting and a power source medium, the circuit or electrical is covered from view by the wall plate; the wall plate that couples to the lighting means; the emergency switch means interconnects the power source means with the lighting means when the field detection means fails to detect the electrostatic field to provide emergency lighting when the energy is lost in the medium that generates the electrostatic field; a resetting means adapted to automatically locate the electrical circuit means in an active state followed by the loss of the electrostatic field of the medium that generates the electrostatic field and a manual power cut of the lighting means, such that a subsequent return of the electrostatic field and a second loss of the electrostatic field provides additional ignition of the illumination means.

2. The device according to claim 1, characterized in that the means generating the electrostatic field is a wall switch having an energy interconnecting means extending externally thereof, the wall plate providing an opening for receiving the medium of interconnection of energy of the medium that generates the electrostatic field.

3. The device according to claim 2, characterized in that the wall plate includes at least one open portion placed and coupled with the lighting means to be seen directly from the lighting means.

4. The device according to claim 2, characterized in that the wall plate includes at least a portion of light transmission placed and coupled with the lighting means to be seen indirectly from the lighting means.

5. The device according to claim 2, characterized in that the wall plate provides a central portion including the opening, and a peripheral portion around the opening, for • include the means of electrical circuit.

6. The device according to claim 2, characterized in that additionally 15 includes a test switch interconnected with the electrical circuit to test the circuit by its manual activation.

7. The device according to claim 2, characterized in that it additionally includes a low battery detector interconnected with the electrical circuit to detect a low battery condition to activate the lighting means and indicate a low battery condition. 25

8. The device according to claim 2, characterized in that the detector means of the electrostatic field is an antenna, the emergency interconnection means is a transistor directed by an amplified signal provided by the antenna, the illumination means is a plurality of devices of LED, and the means of power source is a battery.

9. The device in accordance with the • claim 1, characterized in that the means that generates the electrostatic field in an electrical outlet means that has an electrical plug means therein, and the medium that engages the medium 15 which generates the electrostatic field is an electric plug means adapted to couple the electric plug means of the electrical outlet means.

10. The device according to claim 9, characterized in that the wall plate includes at least one open portion positioned and coupled with the lighting means to be viewed directly from the lighting means. 25

11. The device according to claim 9, characterized in that the wall plate includes at least a portion that transmits light placed and coupled with the lighting means to be seen directly from the lighting means.

12. The device according to claim 9, characterized in that the wall plate provides a central portion including the means that couples to the interconnection means, and a peripheral portion for closing the electric circuit means.

13. The device according to claim 9, characterized in that it additionally includes a test switch interconnected with the electrical circuit to test the circuit by means of its manual activation.

14. The device according to claim 9, characterized in that it additionally includes a low battery detector interconnected with the electrical circuit to detect a low battery condition and to drive the lighting means to indicate a low battery condition.

15. The device according to claim 9, characterized in that the electrostatic field means is an antenna, the emergency interconnection means is a transistor controlled by an amplified signal provided by the antenna, the lighting means is a plurality of LED devices , and the means of energy source is a battery.