Abstract:
A signaling system employing indicator lamp means and an audible alarm is employed to remind a user to periodically test his GFCIs and to provide information regarding the status of the GFCI. The power lines that supply the GFCI with power are also coupled to the circuits on the PCB to disconnect power to those circuits of the GFCI that trips due to faults or tests.

Description:
FIELD OF THE INVENTION 
     The invention pertains to ground fault circuit interrupters (GFCIs) and more particularly to a GFCI which employs a combination of colored lights and an audible alarm signal to shown various states of the GFCI and designate time periods for taking certain actions. 
     DESCRIPTION OF THE PRIOR ART 
     Present GFCI&#39;s generally provide no information to the user as to the status of the GFCI. One GFCI currently on sale provides a single LED to show that the device is operating, that is that the main switch contacts are closed. 
     SUMMARY OF THE INVENTION 
     The present invention provides a GFCI that gives the user a great deal of information on the status of the GFCI and the circuit it is to protect. The GFCI includes a dual color lamp which can produce three distinct colors. Further, the lamp is intended to be blinked at a first slow rate or a second higher rate. An audible alarm can be operated or maintained silent. The information given the user will depend upon the color of the lamp, the speed at which it is blinked and the presence or absence of an audible alarm signal. It is an object of the instant invention to provide a novel GFCI. 
     It is another object of the instant invention to provide a novel GFCI with signaling means to show the status of the GFCI and associated circuits. 
     It is another object of the instant invention to provide a novel GFCI with signaling means comprising blinking colored lights and an audible alarm to show the status of the GFCI and associated circuits. 
     Other objects and features of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principles of the invention, and the best mode which is presently contemplated for carrying them out. 
    
    
     BRIEF DESCRIPTION THE DRAWING 
     In the drawing in which similar elements are given similar reference characters: 
     FIG. 1 is a perspective view of a GFCI constructed in accordance with the concepts of the invention. 
     FIG. 2 is a bottom perspective view of the GFCI of FIG.  1 . 
     FIG. 3 is similar to FIG. 1 but with the top and bottom covers of the GFCI removed. 
     FIG. 4 is a perspective view of the mounting strap of the device of FIG.  1 . 
     FIG. 5 is a bottom perspective view of the load neutral and load phase terminals of the device of FIG.  1 . 
     FIG. 6 is a perspective view of the printed circuit board and reset assemblies of the device of FIG.  1 . 
     FIG. 7 is a perspective view of the devices of FIG. 6 with the reset lever and PC board removed. 
     FIG. 8 is a perspective view of the bobbin assembly of the device of FIG.  1 . 
     FIG. 9 is a perspective view of the main movable contacts of the device of FIG.  1 . 
     FIG. 10 is a bottom perspective view of the plunger, latch plate and auxiliary contacts of the device of FIG.  1 . 
     FIG. 11 is a perspective view showing the transformers mounted on the printed circuit board of the device of FIG.  1 . 
     FIG. 12 is a side elevational view partly in section of the transformer bracket assembly of FIG.  11 . 
     FIG. 13 is a perspective view of the test lever and button of the device of FIG.  1 . 
     FIG. 14 is front elevational view of the test lever, test button, test arm and test pin in the open position. 
     FIG. 15 is a front elevational view of the components shown in FIG. 14 in the closed, test position. 
     FIG. 16 is a perspective view of the reset lever and reset button of the device of FIG.  1 . 
     FIG. 17 is a front elevational view of the reset lever reset button, main contacts and auxiliary contacts in the closed or reset condition. 
     FIG. 18 is a side elevational view of the device according to FIG.  17 . 
     FIG. 19 is a front elevational view of the components of FIG. 17 in the tripped condition. 
     FIG. 20 is a side elevational view of the device of FIG. 19 
     FIG. 21 is a table to show the relationships between the status of the GFCI and associated circuits and the color, speed of blinking and the presence or absence of an audible signal. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Turning now to FIGS. 1 and 2, a complete GFCI  30  constructed in accordance with the concepts of the invention is shown. 
     GFCI  30  is made up of a top cover  32 , middle housing  34  and a bottom housing  36  held in assembly by the deflectable tabs (not shown) on bottom housing  36  engaging the U-shaped members  38  on top cover  32 . A mounting strap  40  is mounted between top cover  32  and middle housing  34  and has two apertures  42  to mount the GFCI  30  to the mounting ears of a standard gang box (not shown). Top cover  32  has a face  44  which contains two sets of slots each to receive a three-bladed grounded plug (not shown). Each set of slots is made up of a slot  46 ,  48  of a first length and a slot  50 ,  52  of a longer length and a U-shaped slot  54 ,  56  to receive the grounding prong of the plug. Because the slots  50 ,  52  are longer than the slots  46 ,  48  the plug is naturally polarized and conforms to NEMA standard  5 -15R. In the depression  58  in top cover  32  is placed a reset button  60 , a test button  62  and an indicator lamp means  64 . Indicator lamp means  64  is a dual color lamp which produces a first color when a first filament is activated, a second color when a second filament is activated and a third color when both filaments are activated. Bottom housing  36  has a series of four terminal screws (only two of which are shown in the figures). Terminal screw  66  is connected to the load neutral terminal as will be described below. A similar terminal screw  68  is connected to the load phase terminal. Terminal screw  70  is connected to the line neutral terminal and a similar terminal screw  72  is connected to the line phase terminal as will be described below. Adjacent each terminal screw  66 ,  68 ,  70  and  72  are two apertures  74  to receive the bared ends of electrical conductors (not shown). As will be described below, the conductor ends extend between a terminal contact and a wire nut which engages the conductor and pushes it against the terminal contact as the terminal screw is advanced. At the rear wall of middle housing  34  is a grounding screw  76  to which may fastened a ground conductor (not shown inserted into slot  78 .) 
     Turning now to FIG. 3 which shows GFCI  30  with the top cover  32  and the bottom housing  36  removed and FIGS. 4 and 5 which show details of the mounting strap  40  and the load phase and neutral terminals. Mounting strap  40  has two apertures  42  as above described and a generally centrally located circular opening  80  to receive the reset lever and a square opening  82  to receive the test lever. Two clips  84 ,  86  are arranged to engage the grounding prong of inserted plugs and are connected to mounting strap  40  by rivets  88 . A bent down tab  90  has a threaded aperture to receive the ground screw  76 . A ground nut  92  is pulled against tab  90  as ground screw  76  is advanced to hold the bared end of a conductor inserted in slot  78  and between tab  90  and ground nut  92 . 
     FIG. 5 shows the load neutral terminal  94  and the load phase terminal  96 . Each terminal  94 ,  96  has a central body portion  98 ,  100 , respectively, with male blade grip fingers  102 ,  104  at each end. The male blades of the plug with fit between each pair of grip fingers  102 ,  104  to make mechanical and electrical contact with the male blades of the inserted plug. An interned tab  106  on load neutral terminal  94  receives the main fixed neutral contact  106  while interned tab  110  receives the main fixed phase contact  112 . A depending three sided tab  114  has a slot  116  to receive therethough the threaded portion of terminal screw  66 . A similar depending three sided tab  118  has a slot  120  to receive therethrough the threaded portion of terminal screw  68 . 
     In FIG. 3 the mounting strap  40  of FIG.  4  and the terminals  94 ,  96  of FIG. 5 are shown assembled to middle housing  34 . Also mounted to middle housing  34  is the printed circuit board (hereafter PCB)  122  which contains the various circuits which determine the indicator lamp means color, its blinking rate and control the beeper. The PCB  122  also contains the various components of the fault detectors, transformers and solenoid as will be described below. Terminal screw  70  is connected to a tab  124  having a slot  126  therein to receive the threaded portion of terminal screw  70 . A similar structure is present for terminal screw  72  not visible in the figure. 
     Referring now to FIG. 6 the PCB  122  assembly and the reset assembly are shown with the middle housing  34  removed. The reset assembly comprises a reset button  60 , a reset lever  128  and a reset spring  130  and a latch pin to be described below with respect to FIGS. 16 to  20 . A plunger  132  is positioned in the passageway of a solenoid coil  134 . The plunger  132  is shown in its reset position extending partially out of the passageway of solenoid coil  134 . When the solenoid coil  134  is operated by the circuits on the PCB  122  the plunger  132  is drawn further into solenoid coil  134 . The plunger  132  controls the position of the latch plate to be described with reference to FIG.  10 . The latch plate in cooperation the latch pin and reset spring  130  move the lifter  136  upwardly against the movable contact arms  138  to close the main movable contacts  140  to the main fixed contacts  108 ,  112  on the underside of interned tabs  106 ,  110 , respectively. The movable contact arms  138  are biased away from their associated interned tabs  106 ,  110  and when the latch pin has been released push the lifter  136  and latch plate downwardly to move the movable contacts  140  away from their associated fixed contacts  108 ,  112 . Also mounted on the PCB  122  is a neutral transformer  142  and a differential transformer  144 . Only the neutral transformer  142  is shown in FIG.  6 . Both transformers and the transformer bracket assembly  146  are shown in FIG.  12 . Neutral transformer  142  is stacked upon differential transformer  144  with a fiber washer  148  therebetween. The bracket assembly  146  substantially surrounds the transformers  142 ,  144  except for a slot  150  as shown in FIG.  11  and slots into which conductors are placed. The leads for the windings of the transformers are brought out to four transformer pins  152  to which may be coupled the line and load conductors. One of the transformers will sense the current going to the load from the source and the other will sense the current from the load back to the source. Any difference in current through these transformers is an indication that there is a fault in the circuit wiring. A device which can measure small differences in current and supply a fault signal is an integrated circuit available from many sources, for example, type number LM1851 from National Semiconductor or type number MC3426 from Motorola. This IC is located on PCB  122 . The line neutral terminal  154  and the line phase terminal  156  have arms  158 ,  160  (see FIG. 9) which extend through the slots in the top of transformer bracket assembly  146 . As shown in FIG. 7, terminal screw  70  extends through slot  126  of tab  124  that is part of line neutral terminal  154  and into a threaded aperture in nut  162  to thus connect the line neutral conductor (not shown) to the two transformers. The arms  158 , 160  act as one turn windings for the transformers  142  and  144 . The line phase conductor (not shown) is connected via terminal screw  72  to tab  164  which extends through a slot  166  in tab  164  into the threaded aperture of a nut  168 . Tab  162  is part of the line phase terminal  156 . An insulator  168  extends between the arms  158 ,  160  to prevent shorting between them. The solenoid coil  134  is connected to two bobbin pins  170  to permit connection to PCB  122 . FIG. 7 is similar to FIG. 6 but omits the PCB  122 , the reset button  60 , the reset lever  128  and the reset spring  130 . 
     FIG. 8 shows the bobbin assembly  172  having solenoid coil  134  connected to bobbin pins  170  and containing plunger  132  in its passageway. A chamber  174  receives the lifter  136  and supports the lifter  136  when in its low position. A cross member  176  supports the auxiliary switch made up of auxiliary fixed contact arm  178  and auxiliary movable contact arm  180 . The auxiliary switch when auxiliary fixed contact  186  and auxiliary movable contact  188  are engaged provides power to various components on the PCB  122 . The auxiliary switch, when auxiliary fixed contact  186  and auxiliary movable contact  188  are not engaged cut-off the power to the components on PCB  122  and prevent possible damage to the PCB  122  components. For example, if the signal to the solenoid coil  134  were repeatedly applied while the main contacts are open there is a chance to burn out the solenoid coil  134 . The auxiliary movable contact arm  180  is biased towards auxiliary fixed contact arm  178  and will engage it unless forced to open the contacts. 
     FIG. 9 shows the lifter  136  in contact with the movable contact arms  138  and positioned by the latch plate  182  which in turn is controlled by the plunger  132  and the plunger reset spring  184 . The lifter  136  and latch plate  182  positions are dependent upon the reset lever  128  position as will be described below. The lifter  136  also controls the auxiliary movable contact arm  180 . When the lifter  136  in its low position, the auxiliary movable contact  188  is moved away from contact with the auxiliary fixed contact  188  (not shown). A latch plate return spring (not shown) resets the latch plate once the plunger  132  is reset as will be set out with respect to FIG.  10 . 
     In FIG. 10 there is shown the latch plate  182 , the plunger  132  and the auxiliary fixed arm  178  with auxiliary fixed contact  186  and the auxiliary movable arm  180  with auxiliary movable contact  188 . Plunger reset spring  184  is anchored on the back edge  200  of latch plate  182  and the tab  198  extending into the rectangular opening  196 . When the plunger  132  is moved to the right in FIG. 10 as a result of the activation of solenoid coil  134  the plunger reset spring  184  is compressed and expands to return the plunger  132  to its initial position partially out of the solenoid coil  134  as shown in FIG. 6 when the solenoid coil  134  is deactivated. Latch plate return spring  190  is connected between lifter  136  and tab  198  and is compressed by the movement of latch plate  182  to the right in FIG. 10 due to movement of plunger  132  to the right as well. When the plunger  132  is withdrawn, the latch plate return spring  190  expands to return the latch plate  182  to the left in FIG.  10 . The arms  192  support arms of lifter  136 . A central aperture  194  is oval in shape with its longer axis extending along a central longitudinal axis of latch plate  182 . At the center of aperture  194 , the aperture  194  is large enough for a latch pin (not shown) to pass through aperture  194  and move without engaging the lifter  136 . At one of the smaller ends the latch pin is held by the latch plate  182  and causes the lifter  136  to move with the latch pin as will be described below. The auxiliary movable arm  180  is biased upwardly so that it brings auxiliary movable contact  188  into contact with auxiliary fixed contact  186  on auxiliary fixed arm.  178 . As will be described below an arm of the lifter  136  will engage the auxiliary movable arm  180  to push it downwardly in FIG. 10 to separate the auxiliary movable contact  188  from the auxiliary fixed contact  186  and open the auxiliary circuit. 
     Turning now to FIGS. 13,  14  and  15  the test button  62  is shown and its operation described. Test button  62  has a top member  204  from which extend side members  206 . Also extending from top member  204  is a central lever  208  which contains a cam  210 . The lever  208  extends through square opening  82  in mounting strap  40 . The cam  210 , when the test button  62  is depressed, engages a test arm  212  and moves its free end  214  into contact with test pin  216 . The position of the test pin  216  is shown in FIG.  6 . The test pin  216  is coupled to a small resistor and a lead which extends through one of the transformers  142 ,  144  to produce an unbalance in the power lines and cause the integrated circuit LM1851 to produce a signal to operate the solenoid  134  and thus simulate a fault. The test button return spring (not shown) returns the test button  62  to its initial position. FIG. 14 shows the reset position of test button  64  with cam  210  not depressing test arm  212  and the free end  214  separated from test pin  216 . When the test button  62  is depressed as shown in FIG. 15, the cam  210  forces the free end  214  of test arm  212  downwardly into contact with test pin  216  to cause a simulated fault and operate the GFCI  30  to determine that the GFCI  30  is working properly. When released test button  62  returns to its reset position as shown in FIG.  14 . 
     The reset button  60  is shown in FIG.  16 . Reset button  60  has a top member  218  from which depend side members  220 . Also extending from top member  218  is a latch lever  222  which ends in a latch pin  224 . Latch pin  224  is generally pointed at its free end  228 . The diameter of latch pin  224  is greater than the diameter of the latch lever  222  resulting in a latch shoulder  226 . A reset spring  230  surrounds latch lever  222  as shown in FIG.  17 . FIGS. 17 and 18 show the GFCI  30  in its reset position. FIG. 17 is a rear view while FIG. 18 is a side elevational review. The surrounding structure is shown in light line to permit the switching components of GFCI  30  to stand out. In FIG. 18 the plunger  132  extends out of the solenoid coil  134  and the latch plate  182  is drawn to the left of the figure so that a smaller end of the oval aperture  194  engages the latch lever  222 . The latch pin  224  cannot be drawn through oval aperture  194 . The leading end  232  of latch plate  182  rests upon the latch shoulder  226  and also is positioned under lifter  136 . The reset spring  230  urges the latch lever  222  upwardly causing the lifter  136  to also move upwardly. This upward movement causes the movable contact arms  138  to also move upwardly bringing movable contacts  140  into contact with fixed contacts  108 ,  112  (see FIG.  17 ). The extension  234  of lifter  136  moves away from its contact with auxiliary movable arm  180  and the upwardly braised auxiliary movable arm  180  causes its auxiliary movable contact  188  to engage auxiliary fixed contact  186  on auxiliary fixed arm  178  and thus supply power to the PCB. 
     In response to an internal or external fault or in response to a test employing test button  62 , the GFCI  30 , if working properly will go to a trip state shown in FIGS. 19 and 20 wherein both the main circuits and the auxiliary circuit will be opened. The presence of the trip condition is signaled by the circuits of the PCB. A signal will be supplied to the solenoid coil  134  which draws the plunger  132  further into solenoid coil  134 . Plunger  132  causes the latch plate  182  to move to the right in FIG.  20  and place the central portion of oval aperture  194  over latch pin  224 . In this position leading end  232  of the latch plate  182  not longer engages the latch shoulder  226  and the latch lever  222  is free to move through the oval aperture  194 . As a result there is nothing to hold the movable contacts  140  on movable contact arms  138  in contact with fixed contacts  108 ,  112  on the fixed arms  106 ,  110 , respectively. The movable contact arms  138 , biased downwardly bear upon the lifter  136  moving it downwardly separating contacts  108 ,  112  and  140 . The extension  234  bears against auxiliary movable arm  180  and causes its downward movement separating the auxiliary movable contact  188  from the auxiliary fixed contact  186  and opening the auxiliary circuit to supply power to the circuits on the PCB. The reset button  60  pops up as a result of the action of reset spring  230  to indicate that the GFCI  30  needs to be reset. 
     In addition to the pop-up of the reset button  60 , the GFCI has a dual color indicator lamp means  64  and a priezo resonator  236  driven by an oscillator on the PCB (not shown) to produce an audible output. By selecting the oscillator frequency of 3.0 KHZ±20% and controlling the time of operation of the oscillator, the audible signal shall be active for 0.10 second and inactive for 2 seconds. FIG. 21 shows the various combinations of light color, light flashing speed and beeper sound which can be produced to show various states of the GFCI  30 . A supervisory signal that indicates that the GFCI  30  is working is provided for the first 25 days of the GFCI  30  cycle. It is recommended that the GFCI  30  be tested and reset every 30 days to ensure that the GFCI  30 , is working properly. 
     However, for the most part this instruction is disregarded. To encourage the testing of the GFCI  30  the various lights and beeper approach is employed. At the end of 25 days the slow flashing green light which signaled the device as workings changes to a faster blink. The supervisory or slow blink is 0.10 seconds “on” and 15 seconds “off”. The faster blink is 0.10 seconds on and 0.9 seconds off. This fast blink extends for five days at which time both filaments of the indicator lamp means  64  are energized to produce an amber light which is blinked at the fast blink rate. If the power comes on reset the amber light will also blink at the fast rate until the supervisory condition is reached. The time periods are established by a counter and a clock generator on the PCB. If an external fault is detected the amber light is lit and the audible signal is generated. The GFCI  30  will need to be reset. If the fault is in the GFCI  30  itself, for example the solenoid coil  134  is burned out, then the red filament of the indicator lamp means  64  is activated and the audible signal is generated. The GFCI  30  will have to be replaced if the fault is in the GFCI  30 . 
     While there has been shown and described and pointed out the fundamental novel features of the invention as applied to the preferred embodiment, as presently contemplated for carrying them out, it will be understood that various omissions and substitutions and changes of the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention.