Abstract:
A circuit interrupting system has an upper cover, an intermediate support, and a base. A mounting strap is installed between the upper cover and the intermediate support, and a electric circuit board installed between the intermediate support and the base. The upper cover includes an electric output plug, a test button, and a reset button. The mounting strap includes a ground point that is connected to a ground receptacle of the electric output plug; the intermediate support on both sides a pair of output conductors. The electric circuit board comprises a differential transformer, a solenoid coil having a plunger inside, a reset button bias member, and a flexible switch; both sides of the base respectively comprise in parallel a pair of electric input connection screws and a pair of electric output point. The ground fault circuit interrupting system is installed within an output box on the wall of an ordinary household which prevents hazard caused to human and household electronics by errors in the installation of the connection lines.

Description:
RELATED APPLICATION 
   This application claims the priority of Chinese Patent Application No. 02243497.6, filed on Aug. 7, 2002, which is incorporated herein by reference. 
   FIELD OF THE INVENTION 
   The present invention relates to a receptacle device, particularly a ground fault circuit interrupter (GFCI) or an arc fault circuit interrupter (AFCI), which provides protection to humans and property against faults in electrical equipment and in electrical supply and distribution systems so that upon detection of a fault condition, the receptacle device interrupts the electric supply circuit. The receptacle device is also capable of protecting against faults caused by reverse wiring. 
   BACKGROUND OF THE INVENTION 
   Safety associated with the use of household appliances is a great concern for people. This is especially the case as more and more electronic devices are used in homes today. Accordingly, it is desired to provide the electric receptacles in the walls of ordinary households with safety features. However, most receptacles in homes are ordinary receptacles without the capability to protect against leakage of electric current. When these ordinary receptacles are used, leakage of electric current or a shock hazard may occur. 
   Receptacles with safety features that guard against the leakage of electric current, such as a ground fault circuit interrupter (GFCI) and an arc fault circuit interrupter (AFCI), have been in existence since the early 1970s. However, until recently, most of these receptacles did not possess a reverse wiring protection feature. Reverse wiring means that load wires are mistakenly connected to a line side of the receptacle and line wires are mistakenly connected to a load side of the receptacle. When this occurs, although the input end and the output end of the receptacle are still electrically connected, the receptacle no long provides fault-protection. Without a reverse wiring protection feature, a consumer, after mistakenly reversing the line wire and load wire connections to the receptacle may be misled to believe that the receptacle is still functioning properly and will detect a fault condition. However, the consumer does not know that the fault-protection feature is not operational. The continued use of a reverse wired receptacle might cause injury to users and damage to the household electronic appliances, as well as damage to real property. 
   Accordingly, there is a need for a circuit-interrupting device that provides reverse wiring protection and that may also protect against fault conditions, such as ground faults and arc faults, among others. 
   SUMMARY OF THE INVENTION 
   To solve the above problems, embodiments of the present invention provide a circuit interrupting device, such as a GFCI or an AFCI. This type of circuit interrupting device is suitable for installation in an output box in a wall of an ordinary household, such as a typical wall receptacle. When the input and output wires are mistakenly connected in a reverse manner during installation of the receptacle, the receptacle prevents an electric connection between the input end and output end of the receptacle. Thus, when the input wire is mistakenly connected to the output end of the receptacle and the output wire is mistakenly connected to the input end of the receptacle, there is no electric voltage output from the receptacle. Only when the wires of the receptacle are properly connected can the receptacle be reset and the output end provide a voltage output. 
   Embodiments of the present invention provide a receptacle mainly comprising an upper cover, an intermediate support, and a base. A mounting strap is installed between the upper cover and the intermediate support, and an electric circuit board is installed between the intermediate support and the base. 
   The upper cover comprises an electric output plug, a test button, and a reset button. 
   The mounting strap comprises a ground point that is connected to a ground receptacle of the electric output plug through an opening in the upper cover. 
   The intermediate support comprises a pair of output conductors made of conductive materials. The two output conductors each have pieces corresponding to the hot receptacle and the white receptacle on the electric output plug on the upper cover. The output conductors also comprise, respectively, electric contacts corresponding to electric contacts on a flexible electric input piece on the electric circuit board. A test button switch piece is located between one of the output conductors and the test button. 
   The electric circuit board comprises a pair of flexible input components having four flexible input fingers, a differential transformer for testing for leakage of electric current, a solenoid coil having a plunger therein, a reset button bias member, and a flexible switch. 
   The flexible input components are located on both sides of a central opening in the reset button bias member and passes through the differential transformer to connect to the electric input point. The flexible input fingers include two pairs of electric contacts, one pair of the electric contacts correspond to a pair of the electric contacts on the output conductor in the intermediate support, while the other pair corresponds to a pair of electric contacts on the output conductors. 
   The base encloses the electric circuit board and the intermediate support. Both sides of the base comprise, respectively, a pair of electric input connection screws and a pair of electric output connection screws connected in parallel. The electric input connection screws connect to the flexible input components in the electric circuit board, and the electric output connection screws connect to the electric output metal pieces in the base. 
   The reset button bias member is comprised of a cylinder located underneath the reset button. A central opening is provided in the reset button bias member, a movable L-shaped latch is arranged at the bottom of the reset button bias member. The latch has an opening. A directional lock is located inside the reset button bias member and vertically passes through the central opening. The directional lock has a bottom surface, and a locking groove is located above and close to the bottom surface of the directional lock. A spring is provided on the directional lock and biases the reset button. Another spring is also located between one side of the reset button bias member and the latch component. 
   The flexible switch is located between the reset button bias member and the electric circuit board. The flexible switch is made of flexible conductive material. A first end of the flexible switch is attached to the electric circuit board and is connected to a resistor. The resistor is coupled to an anode of a rectifier circuit on the electric circuit board. A second end of the flexible switch has a protruding pinpoint contact corresponding to a contact on the electric circuit board, which is in turn connected to a gate trigger of a silicon-controlled rectifier (SCR) that is connected to the solenoid coil on the electric circuit board. 
   A test resistor is located underneath the test button with one end series connected to a white line of the electric input wire. 
   In another exemplary embodiment, a reset apparatus for a circuit interrupting device including a line side connection capable of being electrically connected to a source of electricity; a load side connection capable of being electrically connected to a load side conductor, is provided. The reset apparatus comprises a reset button having a depressed and a relaxed position. A resilient element biases the reset button into the relaxed position. A directional lock is coupled to the reset button and has a bottom surface. A bias member is arranged under the reset button, the reset bias member defines a central aperture therein receiving the directional lock. The directional lock is moveable in a vertical direction in the aperture. A first pair of electric contacts is provided for making an electric connection between the line side connection and the load side connection. A latch extends into the bias member and through the aperture, the latch defines an opening therein and is movable through the aperture in a horizontal direction between an aligned position in which the opening is aligned with the bottom surface of the directional lock and a misaligned position in which the opening is misaligned with the bottom surface of the directional lock. The latch is adapted to engage the directional lock such that movement of the reset button to the relaxed state causes the bias member to close the first pair electric contacts. 
   In another exemplary embodiment the circuit interrupting device comprises a line side connection capable of being electrically connected to a source of electricity. A load side connection capable of being electrically connected to a load side conductor for providing electricity to a load side. A user load connection capable of conducting electricity to at least one load for providing an electrical connection to the source of electricity. A first conductive path provides an electrical connection between the line side connection and the user load connection. A second conductive path provides an electrical connection between the line side connection and the load side connection. A reset mechanism for establishing an electrical connection. First means for detecting a fault condition and second means, separate from the first means, for testing for a reverse wiring condition when the reset mechanism is actuated are also provided. Means interrupt at least one of the first conductive path or the second conductive path when a reverse wiring condition or a fault is detected. 
   According to another embodiment, the circuit interrupting device comprises a first conductor and a second conductor. A first pair of contacts is provided with each contact coupled to one of the first and second conductors. A second pair of contacts is moveable to a closed position via a reset button. A plunger is disposed in a solenoid. The plunger is moveable between a first position and second position when the solenoid is energized and de-energized, respectively. A current controller is coupled to the solenoid and to at least one of the first and second conductors via the second pair of contacts. The current controller prevents current flow through the solenoid to de-energize the solenoid when the first and second conductors are reverse wired and allows current flow to energize the solenoid when the first and second conductors are wired correctly. A fault detection circuit energizes the solenoid when a fault is detected. When the solenoid is energized via the current controller, the plunger initiates closing of the first pair of contacts to complete a circuit between the first and second conductors and when the solenoid is energized via the fault detection circuit the plunger initiates opening of the first pair of contacts to interrupt the circuit between the first and second conductors. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a three-dimensional exploded view of the circuit interrupting device of the present invention. 
       FIG. 2  is a perspective view of the circuit interrupting device of an embodiment of the present invention. 
       FIG. 3  is a perspective view of the circuit interrupting device of an embodiment of the present invention without the upper cover. 
       FIG. 4  is a view of the components on the electric circuit board placed inside the base of the circuit interrupting device of an embodiment of the present invention. 
       FIG. 5A  is a sectional view of  FIG. 3  following line A—A, schematically showing an interruption of the electric connection between the electric input end and the electric output end in the circuit interrupting device of an embodiment of the present invention. 
       FIG. 5B  is a sectional view of  FIG. 3  following line B—B, schematically showing an interruption of the electric connection between the electric input end and the electric output end in the circuit interrupting device of an embodiment of the present invention. 
       FIG. 6A  is a sectional view of  FIG. 3  following line A—A, schematically showing the electric connection between the electric input end and the electric output end in the circuit interrupting device of an embodiment of the present invention. 
       FIG. 6B  is a sectional view of  FIG. 3  following line B—B, schematically showing the electric connection between the electric input end and the electric output end in the circuit interrupting device of an embodiment of the present invention. 
       FIG. 7A  is a sectional view of  FIG. 3  following line A—A, schematically showing the interruption of the electric connection between the electric input end and the electric output end in the circuit interrupting device of an embodiment of the present invention. 
       FIG. 7B  is a sectional view of  FIG. 3  following line B—B, schematically showing the interruption of the electric connection between the electric input end and the electric output end in the circuit interrupting device of an embodiment of the present invention. 
       FIG. 8  is a schematic diagram of the electric circuit of the circuit interrupting device of an embodiment of the present invention. 
   

   DETAILED DESCRIPTION OF INVENTION 
   As shown in  FIGS. 1–4 , a circuit interrupting device, for example a GFCI, an AFCI, or other device, according to an exemplary embodiment of the present invention mainly comprises an upper cover  2 , an intermediate support  3 , and a base  4  assembled together. As shown in  FIG. 2 , on the upper cover  2 , there are two electric output plugs  5  and  6 , a test button (TEST)  7 , and a reset button (RESET)  8 . 
   A mounting strap  1  is installed between the upper cover  2  and the intermediate support  3 . The mounting strap  1  has ground points  11 ,  12  that are connected to ground receptacles of the electric output plugs  5 ,  6  through openings in the upper cover  2 . An electric circuit board  18  is installed between the intermediate support  3  and the base  4 . 
   As shown in  FIG. 3 , the intermediate support  3  includes a pair of output conductors  13 ,  14  that are made from conductive materials. The output conductors  13 ,  14  are disposed on either side of the support  3 . The two output conductors  13  and  14  have conductive members  60 ,  61 ,  62 , and  63  corresponding to the hot receptacles and white receptacles of the electric output plugs  5 ,  6  in the upper cover  2 . Additionally, the output conductors  13 ,  14  also comprise, respectively, electric contacts  15  and  16 . A test button switch piece  40  is located between one of the output conductors  13 ,  14  and the test button  7 . 
   As shown in  FIG. 1 , the base  4  is used as a housing to enclose the intermediate support  3  and the electric circuit board  18 . Both sides of the base  4  comprise, respectively, a pair of electric input connection screws  9  (HOT) and  10  (WHITE) and a pair of electric output connection screws  109  (HOT) and  110  (WHITE), coupled in parallel. Inside the base  4 , there are a pair of electric output leads  81  and  80  connected to the electric output connection screws  109  (HOT) and  110  (WHITE) respectively. The electric output leads  80  and  81  have two electric contacts  52  and  53 , respectively. 
   As shown in  FIGS. 4 and 5A , inside the base  4 , the electric circuit board  18  comprises a pair of electrically conducting flexible input components  95 ,  96  having four flexible input fingers  20 ,  21 ,  50 , and  51 , a differential transformer  19  for testing for leakage of electric current, a solenoid coil  26  having a plunger  42  therein, a reset button bias member  28 , and a flexible switch  37 . 
   The flexible input fingers  20 ,  21 ,  50  and  51  at one end of the flexible input components  95 ,  96  have electric contacts  22 ,  23 ,  55  and  54 . The other ends of the flexible input components  95 ,  96  pass through the differential transformer  19  to connect via input leads  24  and  25  to the electric input connection screws  9  and  10 . The electric contacts  22  and  23  on the flexible input fingers  20 ,  21  correspond to the electric contacts  15  and  16  on the output conductors  13 ,  14  in the intermediate support  3 . The electric contacts  54  and  55  on the flexible input fingers  50 ,  51  correspond to the electric contacts  52  and  53  on the electric output leads  80  and  81  in the base  4 . 
   Also included on the electric circuit board  18  is a solenoid coil  26 , with a plunger  42  placed inside. A test resistor  27  is located underneath the test button  7  on the upper cover  2 , with one end of the test resistor  27  connected to the input connection screw  10  (WHITE) (See  FIG. 8 ). 
   Referring now to  FIGS. 5A and 5B , the reset button bias member  28  on the electric circuit board  18  is located underneath the reset button  8 . A housing  100  may be provided to support the reset button bias member (See  FIG. 1 ). A portion of the bias member  28  is arranged below the flexible input fingers  20 ,  21 ,  50  and  51 , as best seen in  FIG. 5B . A central opening  29  is provided in the top of the reset button bias member  28 , and a movable L-shaped latch  30  is arranged at the bottom of the reset button bias member  28 . The latch component  30  includes an opening  31 . The latch  30  has a first leg that extends into bias member  28  and through the central opening  29 . The latch  30  is preferably movable in a horizontal direction through the bias member  28 . A second leg of the latch  30  is disposed along side of the bias member  28 . A circular groove  33  is provided between one side of the reset button bias member  28  and the second leg of the latch  30 . The circular groove  33  has a spring  34  fit therein. The spring  34  is biased against the second leg of the latch  30 . A directional lock  35  is located inside the reset button bias member  28  and vertically passes through the central opening  29 . The directional lock  35  has a bottom surface  41 . A locking groove  36  is provided on the directional lock  35 , near the bottom surface  41 . A spring  91  is provided to the top of the directional lock  35 , beneath the reset button  8 . 
   As shown in  FIGS. 5A and 8 , the flexible switch  37 , made of a flexible conductive material, is located between the reset button bias member  28  and the electric circuit board  18 . A first end of the flexible switch  37  is connected to the electric circuit board  18 . A second end of the flexible switch  37  is moveable and has a protruding pinpoint contact  39  that corresponds to a contact  38  disposed on the circuit board  18  underneath contact  39 . The first end of the flexible switch  37  is connected to a rectifier circuit  120 , and the second end of the flexible switch is connected to a gate trigger  121  of a SCR (See  FIG. 8 ). The flexible switch  37  and the SCR are used to test for and to guard against reverse wiring, i.e. to prevent an error in connecting the electric input wiring and the electric output wiring of the circuit interrupting device, as is described in more detail below. 
     FIGS. 5A–6B  indicate an example of a scheme under which the circuit interrupting device of an exemplary embodiment of the present invention works to prevent leakage of electric current and to interrupt an electric connection between the input and the output.  FIGS. 5A and 5B  illustrate an exemplary circuit interrupting device with the circuit interrupted, that is, there in no connection between contacts  15 ,  16 ,  52 ,  53  and contacts  20 ,  21 ,  50 ,  51 , respectively. In  FIGS. 5A and 5B , the reset button  8  is depressed to reset the circuit interrupting device to a conducting state. When the reset button  8  is depressed, the directional lock  35  moves downward. As can be seen in  FIG. 5A , the opening  31  in latch  30  is misaligned, that is, offset, with the bottom surface  41  of the directional lock  35 . Thus the bottom surface  41  cannot pass through the opening  31  and is pressed against the surface of the latch  30 . The downward action of the directional lock  35  against the latch  30  causes the bias member  28  to move downward. Because of the downward movement of the reset button bias member  28 , the pinpoint contact  39  on the flexible switch  37  is moved downward and connected to contact  38  as shown in  FIGS. 5A and 5B . 
   As shown in  FIG. 8 , the flexible switch  37  is connected at one end to resistor  27 , which in turn is connected to an anode  120  of a rectifier circuit. The other end of the flexible switch  37  is connected through the contact  38  to a trigger gate  121  of the SCR. An electric connection between contacts  38  and  39  completes a circuit between gate  121  and anode  120 . When the electric input and output wiring is connected to the circuit interrupting device properly, i.e. no reverse wiring, a positive voltage is provided at anode  120 . This voltage should bias the SCR into a conducting state, allowing current to flow through the solenoid coil  26 . The solenoid coil  26  is thus charged with electricity and yields a magnetic field, which draws the plunger  42  inward to hit on the latch  30 . The latch  30  moves with the plunger  42  against the force of spring  34 , to the left in  FIG. 5A . The movement of latch  30  aligns the opening  31  with the bottom surface  41  of the directional lock  35  such that the bottom surface  41  of the directional lock  35  passes through the opening  31 , as shown in  FIGS. 6A and 6B . 
     FIGS. 6A and 6B  illustrate the state of the circuit interrupting device after the reset button  8  is released. When the reset button  8  is released, the pinpoint contact  39  and the contact  38  of the flexible switch  37  are disconnected. A voltage is no longer present at gate  121  and the SCR is no longer biased into a conducting state. Thus, the electric current no longer flows through solenoid coil  26  and the solenoid coil  26  no longer produces the magnetic field. In turn, the plunger  42  no longer acts on the latch  30 . The spring  34  between the latch  30  and the reset button bias member  28  causes the latch  30  to move back towards its misaligned position, to the right in  FIGS. 5A and 6A . However, since the directional lock  35  is now positioned in opening  31 , the latch  30  cannot move completely back to the misaligned position. Instead, the opening  31  of the latch  30  slides into the locking groove  36  of the directional lock  35 . Due to the force of spring  34 , the directional lock  35  and the latch  30  are engaged with each other as shown in  FIG. 6A . 
   At substantially the same time the connection between contacts  38  and  39  is broken, the release of the reset button  8  allows the spring  91  near the top of the directional lock  35  to move the reset button  8  and the directional lock  35  upward. Due to the engagement of the directional lock  35  with the latch  30 , via the locking groove  36  and opening  31  as described above, the reset button bias member  28  also moves upward. The bias member  28 , in turn, lifts the contacts  22 ,  23 ,  55 , and  54  on the flexible input fingers  20 ,  21 ,  50 , and  51  upward to connect to the contacts  15  and  16  of the output conductors  13 ,  14  and to the contacts  52  and  53  of the electric output leads  80  and  81 , so that the input and output are electrically connected ( FIGS. 6A and 6B ). 
     FIGS. 5A ,  5 B, and  8  also illustrate an exemplary scheme of protection to interrupt the electric connection of the electric input and the electric output on the circuit interrupting device of an exemplary embodiment the present invention when the electric input is mistakenly reverse-wired to the electric output on the circuit interrupting device. When the circuit interrupting device is reverse-wired, the pair of electric input wires are connected to the electric output screws  109 ,  110  and the electric output wires are connected to the electric input screws  9 ,  10 . As indicated in  FIG. 8 , although the circuit interrupting device itself is intact, when the reset button  8  is pressed down so that the two contacts  39  and  38  of the flexible switch  37  are connected, due to the reverse wiring, there is no electric voltage at the trigger gate of the SCR. Thus, the SCR is in a non-conducting state so that no electric current can pass through the solenoid coil  26 . As a result, the plunger  42  does not move inward into the solenoid  26  and does not hit on the latch component  30 . The opening  31  in latch  30  remains misaligned with the bottom surface  41  of the directional lock  35 . The directional lock  35  cannot pass through opening  31  and the bottom surface  41  of the directional lock  35  stays pressed against the surface the latch component  30 . 
   Consequently, when the reset button is released, bias member  28  does not move upward. Therefore, the contacts  22 ,  23 ,  55 , and  54  of the flexible input fingers  20 ,  21 ,  50 , and  51  are not connected to the contacts  15  and  16  of the output conductors  13  and  14  and the contacts  52  and  53  of the electric output leads  80  and  81 , as is shown in  FIGS. 7A and 7B . Consequently, there is no electric connection between the electric input and the electric output. 
     FIGS. 7A ,  7 B and  8  also illustrate the state of an exemplary circuit interrupting device when a fault has been detected. Initially, the circuit interrupting device is in the position illustrated in  FIGS. 6A and 6B , with the contacts closed. When the differential transformer  19  of the circuit interrupting device of an exemplary embodiment the present invention detects a leakage electric current, a signal is provided to the IC ( FIG. 8 ). The IC generates a signal that biases the SCR into conducting state so that the solenoid coil  26  has electric current flowing therein, which produces a magnetic field. The plunger  42  is drawn into the solenoid coil  26  by the magnetic field and hits on the latch  30 , which pushes the latch  30  against the force of spring  34 . The latch  30  is thus moved to its aligned position. The locking groove  36  on the directional lock  35  slides out of engagement with the opening  31  of the latch  30 . The directional lock  35  is now free to move through opening  31 . The reset button  8  moves up due to the force of the spring  91  and pulls the directional lock  35  upwards. The reset button bias member  28  slides downward when pushed by flexible input fingers  20 ,  21 ,  50 , and  51 . In turn, the contacts  22 ,  23 ,  55 ,  54  of the flexible input fingers  20 ,  21 ,  50 , and  51  separate from the contacts  15  and  16  of the output conductors  13  and  14  and the contacts  52  and  53  of the electric output leads  80  and  81 . Thus, the electric connection between the electric input and the electric output is interrupted, as shown in  FIGS. 7A and 7B . 
   When the user wants to disconnect the electric connection between the electric input and the electric output of the circuit interrupting device, the test button  7  is depressed so that the test button switch  40  is connected to the test resistor  27 . When the differential transformer  19  detects a test leakage electric current, the SCR becomes conducting. Consequently, the solenoid coil  26  has electric current flowing therein, which produces a magnetic field. The magnetic field draws the plunger  42  inward so that it hits on the latch  30 , which pushes the latch  30  against the force of spring  34 . The latch  30  is thus moved to the aligned position. The locking groove  36  on the directional lock  35  thus slides out of the opening  31  of the latch component  30 , see  FIG. 7A . The reset button  8  moves upward because of the force of spring  91  at the top of the directional lock  35  and the reset button bias member  28  moves downward due to the flexible input fingers  20 ,  21 ,  50 , and  51 . As a result, the contacts  22 ,  23 ,  55 , and  54  on the flexible input fingers  20 ,  21 ,  50 , and  51  are disconnected from the contacts  15  and  16  of the output conductors  13  and  14  and the contacts  52  and  53  on the electric output leads  80  and  81 . Thus, the electric connection between the electric input and the electric output is interrupted. 
   The above detailed description is illustrative, but not limiting the scope of the present invention. Reasonable variations, such as those occur to reasonable artisan, can be made herein without departing from the scope of the present invention.