Abstract:
A ground fault circuit interrupter (GFCI) with a reset lockout mechanism and reverse wiring protection is applicable to various appliance, instruments, equipments, devices or systems. Its characteristics are that: a lockout mechanism or a reverse wiring protection part is mounted at the reset button, the conducting static contacts of the load side are fixed to the wiring pieces of the load side, and the conducting movable contacts of the line side are in direct touch with the wiring pieces of the load side. As compared with the prior art, the circuit interrupter of this invention has features as follows: smaller volume, less winding turns, more intensive magnetic force of the trip coil, faster tripping speed, more effective and more reliable protection function of the reset button, less sparks produced while the trip is being reset, more steady and better conductivity when supplying power, and simpler structure which makes its assembly work easier, thus productivity can be enhanced and the cost reduced.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a kind of GFCI, especially to GFCI with a reset lockout and reverse wiring protection mechanism. It is widely used in various appliances, devices, instruments, equipments and systems.  
       ART BACKGROUND  
       [0002]     Most electric wire connection devices, which are used for appliances, devices, instruments, and systems, have a line side which is connectable to an electrical power supply, and a load side which is connectable to one or more load ends. There is at least a sensing circuit between the line side and the load side. In the event the load side is improperly connected to the power source, or when ground fault occurs, this will not only result in device damage but also fire or serious personal shock hazard will occur. So it is very important to mechanically break the electrical connection between the line side and the load side promptly when the instance occurs.  
         [0003]     In the Prior Art:  
         [0004]     (1) U.S. Pat. No. 4,595,894 has described a “ground fault circuit interrupter system—GFCIS”, this system uses an electrically activated trip mechanism to mechanically break an electrical connection between the line side and the load side. When the fault occurs, the device cannot reset even operate the reset button for more than 10 times and it will stay in the tripped condition. However, instances may arise where an abnormal condition, caused by, for example, a surge current, may result in disabling of a trip mechanism. The device can be pressed down, i.e., may be reset without the ground fault protection available.  
         [0005]     (2) This invention relates to a commonly owned CN patent NO.031163157 (published NO.CN1441449A) which describes a ground fault circuit interrupter with a reverse wiring protection mechanism connected to a reset button on the load side. The reset button will stay in the tripped condition while the power source is miswired to the load side, or when ground fault occurs. It cannot be reset even when the reset button is operated for more than 100 times until the miswiring is corrected. Comparing with the prior art (1), it provides a more reliable reset button, a simpler structure and lower cost, which is suitable for producing in batch. But there is still room for improvement, for example, the reset button may be designed in such a way it can never be pressed down while the power source is miswired to the load side, and when ground fault occurs, thus the protection may be more effective. Its structure may be further simplified to improve productivity and lower its cost.  
       SUMMARY OF THE INVENTION  
       [0006]     In order to overcome the shortcomings of the prior art, the present invention provides a GFCI with reset lockout and reverse wiring protection mechanism. While the power source is miswired to the load side, or when ground fault occurs, the reset button cannot be pressed down all the time, and keeps the GFCI in the tripped condition. The structure is further simplified and productivity is enhanced.  
         [0007]     The present invention adopts an art as follows: The circuit interrupter includes a reset button and a test button. A lockout mechanism or a reverse wiring protection mechanism is mounted onto the reset button. Two static contacts of the load side are fixed to the two wiring pieces of the load side respectively, and two conducting movable contacts of the line side make direct touch with the conducting static contacts of the load side. These further improve the trip mechanism and increase magnetic force.  
         [0008]     If the AC power is miswired to the load side, there will be no current in the receptacle face all the time, as the load side is interrupted by the separation of socket static contact conducting pieces. When the GFCI is in tripped condition, its reset trip lockout cannot be pressed down all the time, because its trip lockout rod is in locked condition, which prevent the reset button from being reset, avoid usage in reverse wiring condition, and so provides safety.  
         [0009]     As said before, if the AC power is miswired to the load side, even operate the reset button which is in the tripped condition to reset the device, it will trip again, thus prevent the power being supplied to the receptacle face. Even some one operates the reset button continuously, the device will not reset, thus avoid the damage to the electrical appliance and hurt to the user caused by reverse wiring and prolong the life of the device as well. When the AC power is properly wired to the line terminals, pressing down the reset button and current will flow through the receptacle static contact conducting pieces and out to the load side, where the user accessible load side connection may includes one or more connection points, thus ensures the breaker will work normally. At this time, the reset lockout mechanism will not affect the GFCI being reset or making false trip.  
         [0010]     The advantages of the present invention are apparent. With lockout mechanism mounted onto the reset button, the lockout mechanism will “lock” the reset button, which makes it impossible to pressed down while the device is miswired or when ground fault occurs. The device will remain in the tripped condition until the faults is corrected. With reverse trip protection device mounted onto the reset button, while the device is miswired or when ground fault occurs, every time the reset button is pressed down, it will spring up immediately and stay in the tripped condition forever even it is operated for more than 100 times or up to thousands of times until the faults is corrected. Therefore, the reset button of the device of the present invention is more reliable, and while the trip is being reset, less spark will be produced.  
         [0011]     Moreover, according to the present invention the two conducting movable contacts of the line side make contact with the conducting static contacts on the two load side wiring pieces directly. Comparing with the prior art (2), the two reverse movable contacts are now removed, making the structure simpler, assembling work easier and enhancing productivity and further lowering cost. Furthermore, the conducting movable contacts of the line side touch the conducting static contacts of the load side directly, which makes the electric conduction more stable and more effective. Thus the GFCI of the present invention not only can effectively prevent device damage and personal hazard but also can become capable of standing the 6KV/3KA electrical surge test and have a good ability of anti-corrosion and anti-moisture.  
         [0012]     The present invention improved the trip mechanism, decreased the number of wire turns in the trip coil and increased magnetic force. All these make structure further simpler, assembling work further easier, action more stable and protection more dependable. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]      FIG. 1  is the inner structural schematic of GFCI of the present invention.  
         [0014]      FIG. 2-1  is a structural schematic diagram, illustrating the reset button with a reset lockout device of the circuit interrupter of the present invention.  
         [0015]      FIG. 2-2  is a structural schematic diagram, illustrating the reset button with a reverse wiring protection device of the circuit interrupter.  
         [0016]      FIG. 3  is the back view of the circuit board  013  for the structure of  FIG. 2-1 .  
         [0017]      FIG. 4  is a schematic diagram of the reset button with the lockout device in  FIG. 2-1 , under a tripped position.  
         [0018]      FIG. 5  is a schematic diagram, illustrating the reset button with the lockout device in  FIG. 2-1 , when reverse wiring exists and it cannot be reset.  
         [0019]      FIG. 6  is the transverse section view of  FIG. 5 .  
         [0020]      FIG. 7  is a schematic diagram, illustrating the connection between the line side and the load side, and the reset button with a lockout mechanism in a reset condition.  
         [0021]      FIG. 8  is a schematic diagram, further illustrating the connection between the conducting movable contacts of line side and the conducting static contacts of the load side.  
         [0022]      FIG. 9  is a more detailed configuration sketch of a lockout device in the reset button.  
         [0023]      FIG. 10  is a more detailed configuration sketch of a reset button with a lockout device and conducting pieces of the load side.  
         [0024]      FIG. 11  is a view of a reset button with a reverse trip protection device in the tripped position.  
         [0025]      FIG. 12  is a view of the reset button with a reverse trip protection device, when the GFCI is in reverse wiring condition, the reset button cannot be reset.  
         [0026]      FIG. 13  is a schematic diagram, illustrating the reset button in the structure of  FIG. 2-2  in reset position, when the GFCI is in reverse wiring condition.  
         [0027]      FIG. 14  is a schematic diagram, illustrating the reset button in the structure of  FIG. 2-2  in the reset position, the line side and the load side are connected.  
         [0028]      FIG. 15  is a more detailed view of the reset button with reverse trip protection device.  
         [0029]      FIG. 16  is a more detailed view of the conducting pieces of the load side. 
     
    
     DETAILED DESCRIPTION OF EMBODIMENTS  
       [0030]     Referring to  FIG. 1 , it shows the internal structure of the circuit interrupter according to present invention. The GFCI consists of a base  023 , the circuit board  013  being placed in the said base  023 , a test button  008  and a reset button  010  being located on the circuit board  013 . Beneath the reset button  010  there is a spring support  009 . There are a toroidal magnetic core sleeve  002  and a magnetic cover  003  placed inside. There are two line sides include wiring screws  006 - 1 ,  006 - 2 , wiring pieces  004 - 1 ,  004 - 2 , pressure pieces  005 - 1 ,  005 - 2  and the two line side conducting pieces  007 - 1 ,  007 - 2  which are connected to the toroidal magnetic core at one end. There are two line side conductors  011 - 1 ,  011 - 2  on the two line side conducting pieces  007 - 1 ,  007 - 2 . The two line side conductors  011 - 1 ,  011 - 2  are connected to two line side conducting movable contacts  012 - 1 ,  012 - 2 . There are two load sides include wiring screws  017 - 1 , 017 - 2  and conducting pieces  018 - 1 , 18 - 2 . On conducting pieces  018 - 1 , 18 - 2 , there are two conducting static contacts  015 - 1 ,  015 - 2  on which there is a silver contact  014 . A trip coil bracket  019  is placed between the two conducting pieces  018 - 1 ,  018 - 2  of the load side. On the trip coil bracket  019 , there are a U-shaped magnet  038  and a trip coil  020  (for detail please refer to  FIG. 9 ). On both sides of the trip coil  020 , there are two reverse trip movable contacts  016 - 1 ,  016 - 2 . There is the reset trip device  022  beneath the reset button  010 . Four assembly screws  001  are mounted on each corner respectively.  
         [0031]     As of the above mentioned structure, when the power source is connected to the line side via the two wiring screws  006 - 1 , 006 - 2 , pressing down the reset button  010  which is in the tripped position, will in turn depress the reset trip device  022 , thus the reset trip latch  030  is forced to lock the reset core rod  025 , and the reset trip device  022  rises back to its original position because of the bias force of the reset spring  027 , the reset button  010  is forced back to its original extended position and the circuit interrupter receptacle will have power through. If ground fault occurs, when overload or current leakage is larger than 5 mA during the operation, the current surge wave induction will activate the trip coil  020 , which in turn causes the reset trip device  022  to activate, and the device is tripped. So it will cut the power and make the circuit interrupter receptacle having no power and ensure safety.  
         [0032]     As seen in  FIG. 1 , in the said GFCI of the present invention, two conducting static contacts  015 - 1 ,  015 - 2  with the silver points  14  are connected to the wiring pieces  018 - 1 , 019 - 2  respectively. When power is applied to the GFCI, the two line side conducting movable contacts  012 - 1 , 012 - 2  touch the load side conducting static contacts  015 - 1 , 015 - 2  directly, thus the electric conducting path is stable and effective.  
         [0033]     Now let&#39;s turn to  FIG. 2-1 , which shows the structure of the reset button  10  with the lockout mechanism in the present invention. As seen in  FIG. 2-1 , the lockout mechanism comprises the reset core rod  025  which has a flat head below the reset button  010 , and a reset spring  027  which fits to the upper end of the reset core rod  025 . Below the reset button  010  is the reset trip device  022 . Below the reset core rod  025  is the reset trip latch  030 . In the trip coil bracket  019  and below the reset trip device  022  are the reset lockout movable contact  031  and a mating reset lockout static contact  032 . A spring supporter  009  is located below the reset button  10 , two trip assistant springs  028 - 1 , 028 - 2  are placed below the two ends of the spring supporter  009  respectively, and two trip assistant springs  028 - 1 , 028 - 2  are pressed on the movable contacts  012 - 1 , 012 - 2  of the reset trip device  022  respectively. On the two sides of the spring supporter  009  are a  20 A receptacle conducting piece  026 - 1  and a  15 A receptacle conducting piece  026 - 2  respectively.  
         [0034]     As seen in  FIG. 2-2 , it shows the structure of the reverse trip protection device. The said reverse trip protection device includes a reset core rod  025  which is under the reset button  010  and has a sharp head on the lower end. A reset spring  027  fits to the upper end of the reset core rod  025 . At the sharp end of the reset core rod  025 , there is a reset trip latch  030 . Two reverse trip conducting springs  033 - 1 , 033 - 2  are located beside the two sides of the trip coil racket  019 . One end each of the two reverse trip conducting springs  033 - 1 , 033 - 2  is fixed to the circuit board  013 , above the other end is the reset trip device  022 . Under the reset button  010 , there is one compression spring bracket  009 . Under the two sides of the bracket  009 , there are two trip assisting spring  028 - 1 ,  028 - 2  which are located respectively on the two movable contacts  021 - 1 ,  021 - 2  of the line side above the reset trip device  022 .  
         [0035]     Referring to  FIG. 3 , it is the reset button of the structure of  FIG. 2-1 , illustrating the location and connection of various reverse conducting components on the back of the circuit board  013 . Among them, the reset lockout movable contact  031  and the reset lockout static contact  032  is connected to the trip coil  020  respectively.  
         [0036]     Referring to  FIG. 4 , it shows, in the structure of  FIG. 2-1 , the reset button  010  with lockout device in the tripped position. When the reset button  010  is in the tripped position, the lower end of the reset core rod  025  is separated from the reset lockout latch  030 . It also shows the circuit interrupter of the present invention that includes the grounding supporter  034 , grounding screw  035 , grounding accessory  037 , and a test piece  24  which is placed below the test button  008 .  
         [0037]     Referring to  FIG. 5 , it shows, in the structure of  FIG. 2- 1 , the condition of the reset button  010  which cannot be reset while the GFCI is in reverse connection. When the reset button is depressed and the reset core is already depressed, the reset lockout movable contact  031  is in contact with the reset lockout static contact  040  already, so the reset button  010  is propped up by the reset latch  030 , the device can&#39;t be reset to deliver power.  
         [0038]     Referring to  FIG. 6 , it is the transverse section view of  FIG. 5 , the reset lockout movable contact  031  is in contact with the reset lockout static contact  032  already, no current flows through the trip coil  020 , the trip coil has no action, the reset button  010  remains in the tripped condition.  
         [0039]      FIG. 7  is the structural diagram of the reset button in  FIG. 2-1  while the line side of the circuit interrupter is connected to the power source and fed with power. When the reset button  010  is depressed, it will bring the reset trip device  022  downward, which causes the reset lockout movable contact  031  making contact with static contact  032 , so current flows into the trip coil  020 , and it utilizes the actuating components of the circuit board to active the coil member. This motivates the trip core  021  to activate the latch  030 , which will bring the trip device  022  rise synchronously, this in turn will move the conducting movable contacts  012 - 1 , 012 - 2  upward and rise along with the trip device  022 , until they touch the socket conducting static contacts and the static contacts of the load side at the same time. Thus the electrical continuity is reestablished. At this time, reset lockout movable contact  031  is in a condition separated from the reset lockout static contact  032  and will never affect the normal operation of the circuit interrupter.  
         [0040]      FIG. 8  is the structure of  FIG. 2-1 . It concerns the reset button  010  of the circuit interrupter with the lockout mechanism, and shows in detail the condition the conducting movable contacts  012 - 1 , 012 - 2  is in touching with the static contacts  015 - 1 ,  015 - 2 , and the location of components in the device. One end of the trip core  021  below the reset button  010  is inserted into the center of the trip coil bracket  019  and magnetic piece  038 , the other end supporting the trip latch  030 . A reset spring  027  fits with the reset core rod  025 . And two trip assistant springs  028 - 1 , 028 - 2  are pressed on the conducting movable contacts  012 - 1 , 012 - 2  respectively.  
         [0041]     Referring to  FIG. 9 , which shows the structure of  FIG. 2-1 , the reset button  010  of the circuit breaker has a lockout mechanism and  FIG. 9  mainly illustrates the position of this components. In the center of the trip device  022  facing the reset button  010 , there is a reset lockout latch  030 , which comprises the reset lockout spring  036  inside. The reset spring  036  and the trip core  021  are separated from each other by a reset trip lockout latch  030 . A reset lockout movable contact  031  and its mating reset tripping lockout static contact  032  are placed on the bottom end of the reset trip device  022 . Over the trip coil  020  on the trip coil bracket  019  is wrapped a U-shaped magnet  038  which is fixed between the two ends of the trip coil bracket  019 . A magnetic cover  040  is placed between the trip core  021  inside the trip coil bracket  019  and the reset trip lockout latch  030 . The magnetic cover  040  and the U-shaped magnet  038  are connected together. Between the trip core  021  and the magnetic cover  040  there is placed the trip core spring  039 . As mention above, in the trip device of this invention there are a U-shaped magnet  038  which is connected with the magnetic cover  040  and the trip core spring  039  placed on one end of the trip coil  020 . It is due to these improvements, the number of coil turns of the trip coil  020  is decreased, its volume is decreased but its magnetic force is increased at the same time.  
         [0042]      FIG. 10  of the structure of  FIG. 2-1  is a more detailed view of the lockout mechanism and the conducting pieces of the load side, showing the structure of the reset lockout mechanism that prevents erroneous reverse wiring more clearly. The conducting pieces  007 - 1 , 007 - 2  are connected to the movable contacts  012 - 1 , 012 - 2  of the line side by the line side conductors  011 - 1 , 011 - 2 . It shows the shape and relative position of the socket conducting piece  026 - 2  and reset lockout movable contact  031 , reset lockout static contact  032  and reset trip device  022 . The trip coil  020  of the trip core  021  and the reset lockout spring  036  are placed on the trip coil  019  in turn. The two load side conducting static contacts  015 - 1 , 015 - 2  with the silver points  014  are fixed to the two wiring pieces  018 - 1 , 018 - 2  respectively.  
         [0043]      FIG. 11 , of the structure of  FIG. 2-1 , is a cutaway view of the reverse wiring protection device in the tripped position. Here the reset button  010  is in the tripped position, while the reverse trip conducting spring  033 - 1  is depressed by the reset trip device  022 , and is separated from the reverse trip contact  016 - 1 .  
         [0044]      FIG. 12 , of the structure of  FIG. 2-2 , is a reverse trip protection device of the reset button  010  in the closed position. When the reset button  010  is depressed, the reset core rod  025  of the reset button  010  is locked by the reset lockout latch  030 . The reset trip device  022  moves upward because of the force of the reset spring  027  and causes the reverse conducting spring  033 - 1  making touch with the reverse trip guarding contact  016 - 1 , so the reverse trip guarding device is in the switch-on position, and the conducting electrical contact  012 - 1  doesn&#39;t touch the conducting piece contact  026 - 1 , so no current flows in the receptacle.  
         [0045]      FIG. 13 , of the structure of  FIG. 2-1 , shows the reverse trip protection device of the reset button  010  in the closed position (see  FIG. 12 ). The trip coil  020  is activated by the energized circuit interrupter and it activates like lightning. The trip core  021  begins to press the reset latch spring  036  because of the magnetic force, and opens the reset trip latch  030 , thus making the reset  010  separate from the reset lockout latch  030 . The trip assistant spring  028 - 1  springs back immediately, and its force pushes the reset trip device  022  to return to the original position, which in turn brings down the reverse trip conducting springs  033 - 1 , 033 - 2  causing them separate from the reverse protection contacts  016 - 1 , 016 - 2 , thus the reverse wiring protection device is put into the open condition.  
         [0046]      FIG. 14  is the structure of  FIG. 2-2 . The electrical continuity between the line side and the load side is established and the reset button  010  is in reset position. When the power source is introduced into the circuit through the line side, pressing down the reset button to activate the reset trip lockout latch  030 , the reset core rod  025  of the reset button  010  is locked by the reset trip lockout  030 . At this moment, reset spring  027  begins moving upward, which help the reset trip device  022  moves upward too. Meanwhile, following the reset trip device  022 , the line side conducting movable contacts  012 - 1 ,  012 - 2  move upward, and connect with two receptacle conducting contacts  026 - 1 ,  026 - 2  and load side conducting static contacts  015 - 1 ,  015 - 2 , so that the load side power of the interrupter gets through. At this time, the reverse wiring device is in the open position, and it will never affect the normal operation of the interrupter.  
         [0047]      FIG. 15  shows the basic structure of  FIG. 2-2  and further illustrates the reverse trip protection device of reset button  010  and the connection of the line side and the load side. As shown in  FIG. 15 , two conducting pieces  007 - 1 , 007 - 2  of the line side are connected respectively to the two conducting movable contacts  012 - 1 , 012 - 2  with the two conductors  011 - 1 , 011 - 2  of the line side. Two conducting static contacts  015 - 1 , 015 - 2  of the load side are fixed respectively to the wiring pieces  018 - 1 , 018 - 2  of the load side. The silver points  014  of the two load side conducting static contacts is in touch with the silver points  014  of the line side conducting movable contacts. The load side is connected to the reverse conducting springs  033 - 1 , 033 - 2  below the reverse trip device  022  through the reverse trip conductors. One end of the trip core  021  is fixed to the center of the trip coil bracket, the other end supports the reset trip latch  030 . The upper ends of the two reverse trip protection contacts  016 - 1 , 016 - 2  pass respectively through the two ends of the reset trip device  022 , and the lower ends are fixed to the circuit board  013 .  
         [0048]      FIG. 16  is a bottom view with the circuit board  013  removed. It shows mainly the structure and the position of the components in the reverse trip protection device and the structure of the load side conducting pieces. At the central part of the reset trip device  022  facing the reset button  010 , is placed a reset trip lockout  030 , which includes the reset lockout spring  036 . There is a reset trip lockout  030  between the reset lockout  036  and trip core  021 . Two reverse trip protection movable contacts  016 - 1 ,  016 - 2  by passing through the reset trip device  022  are set on the reverse trip conducting spring  033 - 1 ,  033 - 2  respectively.