Abstract:
A ground fault circuit interrupter against RCE suitable for various electrical instruments, equipments and systems fed by electrical power supply is characterized in that an erroneous reverse connection mechanism is included in its load end and the reset button comprises a reverse trip mechanism. When electric power is mistakenly connected to the load ends, the reset button will be always in trip situation and the socket on its upper lid will be kept free of electricity even the reset is attempted unless the error connection is corrected. As compared to prior art, the circuit interrupter of this invention has a simple mechanical trip structure which can effectively prevent equipment damage and personal hazard caused by reverse connection. Of course, it had successfully passed the 6 KV/3 KA electric surge test and is highly anti-moist and anticorrosive.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to Chinese patent application Ser. No. 03 1 163 15.7 filed Apr. 11, 2003. 

   FIELDS OF INVENTION 
   The invention related to a ground fault circuit interrupter, and particularly to a ground fault circuit interrupter against reverse connection error (RCE). It is suitable for use in various electrical apparatuses, instruments, devices, equipments and systems fed by power supply. 
   DESCRIPTION OF RELATED ART 
   Most electric wire connection devices have a power source input end and a load end for one or more load connections. Between the input and load ends there must be at least one place where the passage of the electric circuit can be detected. Power source wire or current conducting connections are connected at the input end and load end. Manufacturers of electric wire connection apparatus are incessantly adding circuit interrupting devices or systems so as to be able to cut off current of different loads, like household electrical appliances, electrical products of the consumer class and branching circuit. Household bath rooms and kitchens are among the electric supply circuit where ground fault circuit interrupters are especially needed. 
   In prior art, there is a kind of “ground fault circuit interrupting system (GFCIS)” described in The U.S. Pat. No. 4,595,894, in which a trip mechanism such as trip device enable to reset is triggered to mechanically cut off the electric connection in input and load ends. But under many abnormal conditions, the mechanism used to cut off the circuit will lose its trip capability due to current surge during the cutting off process. 
   This event mostly happens when the reset button is still pressed down and the result is a trip device without function and a reset without ground fault protection which causes electric appliances damage and endangers human safety. 
   For the traditional ground fault circuit interrupters (referred to as GFCI hereafter), in addition to connect a load at the wire, it is possible to connect one or more connection points at the proximity of the load. The wire connecting them to the load end is connected by assembly screws and load is connected to the inner socket by a plug. A point worthy of paying attention to is that of the device connecting outside wires, its input wire is connected to the inlet wire end, and its load wire is connected to the load end. Frequently, the otherwise case happens, that is, GFCI is erroneously connected to the outside electric wire, so that the load wire is connected to the input wire end and the power source wire is connected to load end. This condition is known as the reverse connection which makes the circuit interrupting device be reversely connected and which disables the fault protection for the load connection and the power source, without protection, is always directly supplying power to the socket no matter it is in the trip condition or in the normal condition so that the protection is not provided even remaining of fault protection for load connection. This shows that those devices have been made reversely connected by the connecting wires. Also in the prior art, many GFCIs adopt warning measures like warning labels, indicating lights and warning alarms for erroneous reversely connected wires to notify users to correctly make wire connection to the load end. But only warning is not enough and many devices have been connected reversely by mistake and damages been made. Also in the prior art, some GFCIs are equipped with erroneous connection protection devices and when erroneous reverse connection occurs the protection devices do prevent the reset button from effecting the reset, but power source will still be supplied to socket on the upper lid without protection being offered and you can still get electric power even without performing reset by pressing the reset button and this disables the protection of the protective device and results in equipment damage all the same. 
   SUMMARY OF INVENTION 
   The object of this invention is to overcome the shortcomings of the protective devices in the circuit interrupters of prior art mentioned above and provides a ground fault circuit interrupter against reverse connection error with a simplest mechanical trip structure for the reset button to solve the problem of protection against reverse connection error, and thus safety can be assured and damage loss can be prevented. 
   The circuit interrupter of this invention mainly includes: a case composing a base  003 , a middle frame  002  and an upper lid  001 , a reset button  006  and a test button  007  placed on the upper lid  001 , a grounding bracket  004 , two input ends and two load ends and two socket static contact conduction parts  005 - 1 ,  005 - 2 . The said two input ends respectively have the input end movable contacts  016 ,  017  connected by wires and two load ends respectively have the load end moveable contacts  018 ,  019  connected by wires. To the load end there is connected the erroneous reverse connection mechanism and to the reset button there is connected the reverse trip mechanism. 
   The said middle frame  002  is located separately between the upper lid  1  and the base  003 , or is placed within the base  003 . 
   The said erroneous reverse connection mechanism connected to the load end mainly includes two load end connection parts  15 - 1 , and  15 - 2 , two reverse conducting wires  039  and two reverse trip load end conducting springs  034 - 1  and  034 - 2 . The said two load end connection parts  15 - 1  and  15 - 2  are connected to the reverse trip load end conducting springs  034 - 1  and  034 - 2  thru the reverse conducting wires  039 . 
   The said reverse trip mechanism on the reset button  006  mainly includes two reverse trip movable contact  033 - 1  and  033 - 2 , two reverse trip static contact  032 - 1  and  032 - 2 , the reset trip device  020 , the trip winding bracket  021 , the trip winding  036  successively placed on the trip winding bracket  021  containing the trip armature  024  inside, the trip armature reset spring  026 , the trip winding magnetic pole piece  031  and the reset trip lock pin  025  with the reset lock pin spring  027  inside. The said two reverse trip static contact  033 - 1  and  033 - 2  located on each side of said trip winding bracket  021  are placed on the top of the reverse trip load end conducting springs  034 - 1  and  034 - 2  thru the reset trip device  020  respectively. 
   For the circuit interrupter having the structure as described, when electricity comes in thru the two wire connecting screws  010 - 1  at the input end, if we press down the reset button  006  which moves the reset trip device  020 , the circuit interrupter is now in the reset situation, and the input end movable contact  016  and  017  are in contact with the socket contact conducting parts  005 - 1  and  005 - 2  thus making the sockets of the interrupter supplied with power for costumer&#39;s use. Suppose in the time of usage a ground fault, an over load or a short circuit of a magnitude over 5 mili-ampere occurs, the current surge will excite the trip winding  036  suddenly like a blitz which activates the reset trip device  020  and causes the reset button  006  to trip and separates the input movable contacts  016  and  017  from the socket static contact conducting parts  005 - 1  and  005 - 2 , which in turn, makes the socket of the interrupter loss of power and all instrument, equipment, and personal safety are being protected. In order to continue the usage, fault must be removed first. 
   When erroneous reverse connection is made, current will flow from the load end wire connection parts  15 - 1  and  15 - 2  and are connected to the springs  034 - 1  and  034 - 2  thru wire  039 . Now reverse trip load conducting springs  034 - 1  and  034 - 2  are in contact with reverse trip movable contacts  033 - 1  and  033 - 2  and the reset button  006  is in the trip static situation, but since the reverse trip movable contacts  033 - 1  and  033 - 2  are separated from reverse trip static contacts  032 - 1  and  032 - 2  by a set distance, this prevents the current flow thru the interrupter and thus prevents the usage of a power with erroneous reversely connected lines and safe guard is assured, as shown in  FIGS. 6 and 9 . 
   When power is erroneously connected to the interrupter thru the load end, the outside surface of the interrupter socket is always without electricity because the load end is separated from the socket static contact conducting parts  005 - 1  and  005 - 2 . If reset button  006  is pressed down, then pin  025  is opened, armature  006 - 1  within reset button  006  is locked by pin  025  using the resilience of trip iron core reset spring  026 , thus reset spring  023  begins to raise, which thru the action of device  020  causes the movable contacts  033 - 1  and  033 - 2  to move and the springs  034 - 1  and  034 - 2  at the lower end of contacts  033 - 1  and  033 - 2  then begin to resile and raise simultaneously. When button  006  raises to the set position but yet not to the reset position, contacts  033 - 1  and  033 - 2  touch contacts  032 - 1  and  032 - 2  which excites winding  036  to blitz an induced interruption action which in turn causes armature  024  begin to compress reset trip spring  026  and push forward pin  025  to open the pin lock door, thus after the reset spring  026  resiles the reset button  006  trips off, preventing itself to reset and providing assured safety to users as shown in FIG.  9 . 
   As described above, if a power source is erroneously connected to load end of the circuit interrupter and the reset button  006  is operated in order to change it from its former trip condition to reset condition, it will immediately trip off again and cut off the connection of electric source to the socket on the interrupter. Even repeated pressing down on the button  006  still cannot make it enter into the reset state, thus personal hazard and electric appliance damage are prevent from and the life time of interrupter is increased. If the power source is connected to the input end of interrupter and electric current flows to the load end thru the socket static contact conducting parts  005 - 1  and  005 - 2 , and suppose the user connects one or more connection points near his original load, this will still keep the interrupter operating in normal usage condition and its erroneous reverse connection mechanism would be in a long term open circuit state and will absolutely not affect on the reset and erroneous trip function. 
   The interrupter of this invention has advantagous effect in that: when the power source is erroneously connected to its load end, its anti-RCE (Reverse connection Error) mechanism composed of said erroneous reverse connection mechanism and reverse trip mechanism can assure that there will always have no electric current flowing thru the socket on the surface of the interrupter and its reset button will be situated in trip condition for long term. The interrupter will refuse to be reset even the reset button is repeatelly pressed down for more than 100 times. Reset can be affected only after the erroneous wire connection is corrected. When the circuit interrupter is in service in normal condition, its anti-RCE mechanism will always situate in “off” condition which will absolutely not affect the normal operation of the device and will truly ensure equipment and personal safe. It had passed successfully the 6 KV/3 KA electric surge test and has excellent anti-moisture and anti-corrosion capability. Its cost is low and is suitable for batch production. 

   
     BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS 
       FIG. 1-1  is an outside structural view of the circuit interrupter of the invention for input current of 15 amperes. 
       FIG. 1-2  is an outside structural view of the circuit interrupter of the invention for input current of 20 amperes. 
       FIG. 2-1  is an inner structural view of the circuit interrupter for input current of 15 amperes as shown in  FIG. 1-1  with its upper lid  001  removed. 
       FIG. 2-2  is an inner structural view of the circuit interrupter for input of 20 amperes as shown in  FIG. 1-2  with its upper lid  002  removed. 
       FIG. 3  is an inner structural view of the interrupter shown in  FIG. 2-1  and  FIG. 2-2  with its middle frame removed. 
       FIG. 4  is an cross sectional view of the interrupter shown in  FIG. 6  with its base  003  removed. 
       FIG. 5  is an bottom view of the interrupter shown in  FIG. 3  with its base  003  removed. 
       FIG. 6  is an dissected view of the interrupter showing the triped situation. 
       FIG. 7  is a schematic view showing the situation when reverse direction conduction is on. 
       FIG. 8  is a schematic view showing the electric cut off situation of the erroneous reverse connection mechanism. 
       FIG. 9  is a schematic view showing the electric conduction state after reset of the interrupter with power source connected at its input end. 
       FIG. 10  is a schematic view showing the reverse trip mechanism and the reverse erroneous connection mechanism. 
       FIG. 11  is a bottom view of the interrupter shown in  FIG. 10  with circuit board  035  removed. 
       FIG. 12  is a bottom view of the interrupter shown in  FIG. 3  with the following parts removed: base  003 , circuit board  035 , two assembly parts for input and load ends, magnetic ring sleeve  029  and magnetic ring lid  030 . 
       FIG. 13  is a schematic view showing the disassembled parts of the interrupter of the invention. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Next, a detailed description of the structure of the circuit interrupter according to the invention will be given in below taken in conjunction with accompanying drawings described above. 
   There are two power ratings for the circuit interrupter of the invention: the 15 A rating shown in  FIG. 1-1  and the 20 A rating shown in  FIG. 2-1 . 
   For both interrupters shown in  FIG. 1-1  and  1 - 2 , the outer case, upper lid  001 , base  003  and the grounding bracket  004  are connected together by four assembling screws  008  at the four corners. There are the reset button  006  and the test button  007  installed inside lid  001 , the input end wire connection screws  010 - 1  and load end wire connection screws  010 - 2  installed on base  003 , and the grounding bracket  004  between lid  001  and base  003 , on which is installed the grounding screw  009 . On the upper lid  001  shown in  FIG. 1-1  there are four 15 A socket static contact conducting insertion inlet  005 - 2 - 2 ,  005 - 2 - 3  and  005 - 2 - 4 . On the upper lid  001  shown in  FIG. 1-2 , there are two 20 A socket static contact conducting insertion inlet  005 - 1 - 1 ,  005 - 1 - 2  and two 15 A socket static contact conducting insertion inlet  005 - 2 - 2  and  005 - 2 - 4 . There are two grounding insertion holes  038 - 1  and  038 - 2  on every upper lids  005 . There may be some indicating light on the upper lid  001  but it is not shown on upper lid  001  in  FIG. 1-1  and  FIG. 1-2 . 
   The  FIG. 2-1  and  FIG. 2-2  are respectively those views of  FIG. 1-1  and  FIG. 1-2  with upper lid  001  removed in order to show the inner structure and in particular to show the assembling screws  008  at the four corners and the fact that the middle frame  002  is placed within the base  003 .  FIG. 2-1  shows the two socket static contact conducting parts  005 - 2  of the 15 A interrupter.  FIG. 2-2  shows the socket static contact conducting piece  005 - 1  for use on 20 A and one socket static contact conducting piece  005 - 2  for use on 15 A interrupters. Shown in this figure there are rounding pieces  038  and the grounding screw  009  respectively placed on the two ends of the grounding bracket  004 . On the socket movable contacts  039 - 1  and  039 - 2  are respectively two silver contact points  037  and the test experiment sheet  011  below the test button  007 . Under the load end wire connection screws  010 - 2  are the load end wire connection sheets  015 - 1  and  015 - 2  which may or may be not connected with the two mentioned socket static contact conducting pieces  005 - 1  and  005 - 2  respectively. When the sheets  015 - 1  and  015 - 2  are not connected with the conducting pieces  005 - 1  and  005 - 2  respectively the load end wire connection sheet has no electricity and when otherwise, it has electricity. Shown in  FIG. 2-1  and  FIG. 2-2 , the sheets  005 - 1  and  005 - 2  are not in contact with the two load end wire connections  015 - 1  and  015 - 2 . 
     FIG. 3  is the inner structural view of the interrupter shown in  FIG. 2-1  and  FIG. 2-2  with its middle frame  002  removed. On inner bottom of the base  003  there is placed the circuit board  035  on which are placed the magnetic ring sleeve  029  with magnetic ring inside and the magnetic ring lid  030 . Two input ends contain respectively the wire connection screws  010 - 1 , the input end wire connection pieces  012  and  013 , the input end wire connection cover plate  014 - 1  and the two input movable contact heads  016  and  017  which have wires connected in the middle and have one end inserted into magnetic ring lid  030 . The purpose of contacts  016  and  017  are for the increase of electric conduction capability. The two load ends contain respectively the wire connection screw  010 - 2 , load end wire connection pieces  015 - 1  and  015 - 2  and the two load end movable contacts  018  and  019  which are connected respectively to two load end wire connection pieces  015 - 1  and  015 - 2  by wires. There are placed between the two movable contacts  018  and  019  a trip winding bracket  021  on which are placed the trip winding  036  with trip armature  024  inside. On the sides of the trip winding  036  are placed the reverse direction trip static contact heads  032 - 1  and  032 - 2 . 
     FIG. 4  is the cross sectional view of the interrupter shown in  FIG. 3  with its base  003  removed, which shows the inner structure of the reset trip device. On the upper part of the lock pin armature  006 - 1  with a conical tip below the reset button  006  is hooked with the reset spring  023  and on the lower part of the armature  006 - 1  is hooked with a trip assisting spring  022 . On the conical tip is a reset trip lock pin  025 . Two reverse direction trip load end conducting springs  034 - 1  and  034 - 2  are placed on both sides of the winding bracket  021 , one end of which is fixed on the circuit board  035  while the other end is fixed respectively with the reverse direction trip movable contacts  033 - 1  and  033 - 2 . Placed under the reset button  006  are the socket contact positioning bracket  040  on both sides of which are placed respectively the socket contact positioning springs  041  under which, in turn are placed respectively the socket movable contacts  039 - 1  and  039 - 2  which are connected by wires to the two socket static contact conducting pieces  005 - 1  and  005 - 2  respectively. 
     FIG. 5  is the bottom view of the interrupter shown in  FIG. 3  with its base  003  removed showing the positions where various reverse conducting components on the circuit board  035  are placed and how their wire connections are made.  FIG. 5  also shows the position where the two reverse trip load end conducting springs  034 - 1  and  034 - 2  are connected to the circuit board  035 . The two reverse trip static contacts  032 - 1  and  032 - 2  are connected respectively with the trip winding  036  One end of either two input end wire connection pieces  012  and  013  are respectively connected with the two input end wire connection pieces  012  and  013 , and there is a leg position diagram of the magnetic ring sleeve at the space between  012  and  013 . 
     FIG. 6  is the dissected view of the interrupter showing the triped situation. Here, the reset button  006  is situated in the trip state and one end of the reverse trip mobvable contact  033 - 1  is being attracted by the reverse trip load end conducting spring  034 - 1  and these two are in contact, while the other end of  033 - 1  breaks from the reverse static contact head  032 - 1 . 
     FIG. 7  is the schematic view showing the situation when reverse conduction is on. Here, the reset button  006  is pressed down and its lock pin armature is being locked by the reset trip lock pin  025 . The reset trip device  020  is raised up by resilience of the reset spring  023 , causing the contact  033 - 1  to touch with the conducting spring  034 - 1  and the static contact  032 - 1 . Now the anti-RCE mechanism is situated in the “on” state. There is no connection between the movable contacts of input and load end  016  and  018  and the socket static contact conduction pieces  005 - 1 , so the socket is free of electricity. 
   In  FIG. 8 , when the anti-RCE mechanism is in the “on” state as shown in  FIG. 7 , the trip winding  036  is excited immediately like a blitz by power “off” changed from “on” state, and begins to act, Therefore, the trip armature  024  acted upon by magnetic force begins to compress the reset spring  026 , pushing open the link-release lock pin  025 , causing reset button  006  to separate from lock pin  025 , thus the trip assisting spring  022  immediately resiles. The trip device  020  under the action of resilence returns to the original position and drives the reverse trip movable contacts  033 - 1  and  033 - 2  to move downward and break from the reverse trip static contact  032 - 1  and  032 - 2 . Now the anti-RCE mechanism is situated in the “off” state. 
     FIG. 9  is the schematic view showing the electric conduction state after reset of the interrupter with power source connected at its input end. 
   When power is connected to the input end and reset button is pressed down, reset trip lock pin  025  is opened, the lock armature  006 - 1  is locked by lock pin  025  and reset spring  023  begins to resile to push upward which drives reset trip device  020  to move up and the movable contacts of input  016 ,  017  and load end  018 ,  019  move up simultaneously with the device  020  and make contact with socket static contact conducting pieces  005 - 1  and  005 - 2  thus completing the connection of power to the load end of the interrupter. Now the anti-RCE mechanism is situated in the “off” state and will absolutely not affect the normal function of the interrupter. 
     FIG. 10  is the schematic view showing the reverse trip mechanism and the erroneous reverse connection mechanism. 
     FIG. 10  further shows the positions of the various components in the reverse trip mechanism and erroneous reverse connection mechanism. In the erroneous reverse connection mechanism, the load end movable contacts  018  and  019  connect reverse trip load end conducting spring  034 - 2  or  034 - 1  which are put under the reverse direction trip movable contacts  033 - 2  or  033 - 1  in the reset state thru the reverse conducting wire  039 . In the reverse trip mechanism, one end of the trip armature reset spring  026  is hooked on the head of the trip armature  024  while the other end is pushed against the trip winding magnetic pole piece  031 . 
     FIG. 11  is the bottom view of the interrupter shown in  FIG. 10  with circuit board  035  and the two moveable contacts of input and load end removed.  FIG. 11  is used mainly to show the positions of various trip elements in the reverse trip mechanism. At the central position of trip device  020  opposite to reset button  006  there is placed trip lock pin  025  which contains at its inside the reset lock pin spring  027 . The trip winding magnetic pole piece  031  is located between lock pin spring  027  and armature reset spring  026 . The two reverse trip movable contacts  033 - 1  and  033 - 2  are placed on the top of the reverse direction trip load end conducting spring  034 - 1  and  034 - 2  through the trip device  020  respectively. 
     FIG. 12  is the bottom view of the interrupter shown in  FIG. 3  with the following removed: base  003 , circuit board  035 , the assembly parts for two input and load ends, magnetic ring sleeve  029  and magnetic ring lid  030 .  FIG. 12  shows more clearly the shape and relative positions of the input end movable contacts  016  and  017  of the anti-RCE mechanism, the socket static contact conducting piece  005 - 2 , the reverse trip contacts  032 - 1  and  032 - 2  and the reset trip device  020 . The trip winding  036  of the trip armature  024 , the trip armature reset spring  026  and the reset lock pin spring  027  are successively placed on the trip winding bracket  021 . 
   In  FIG. 13 , structure and shape of all components used in the interrupter of the invention are shown. 
   Although the preferred embodiment of the invention have hereinbefore described, the invention is nonetheless limited only by the following claims.