Patent Application
20130021120
This application claims the benefit of priority of Chinese Patent Applications 201110200616.X filed Jul. 18, 2011, 201110262191.5 filed Sep. 6, 2011, and 201210024531.5 filed Feb. 4, 2012, the contents of which are incorporated herein by reference in their entirety.
The present disclosure relates generally to receptacle type ground fault circuit interrupters. More specifically, the disclosure relates to GFCIs with reverse wire protection that cannot be reset in a reverse wire or trip condition.
Since receptacle type ground fault circuit interrupters (“GFCI”) can not only supply power to the load through the sockets on the upper cover but also can supply power through the load connection assembly to the load connected on it, it is used extensively. The specific structure of the current receptacle type ground fault circuit interrupter generally includes shell, leakage signal detection circuit, electromagnetic tripping mechanism that acts as controlled by the said leakage signal detection circuit, reset key, reset mechanism, grounding assembly, and conductive assembly from power input side to load side. The conductive assembly from power input side to load side includes power input connection assembly and load connection assembly. The load connection assembly includes wiring output assembly and receptacle output assembly.
The said reset mechanism includes a reset bracket. The reset bracket is under the action of the reset key and electromagnetic tripping mechanism. The reset bracket controls a pair of movable contacts in the conductive assembly to connect or disconnect the electrical connection from the power input connection assembly to the load end. However, because the pair of movable contacts of the current GFCI is provided at the free end of a pair of conductors in the conductive assembly and while the other end of the conductor is fixed, and also because the requirements for machining precision of the components are relatively high and the stability of product quality is not ideal, the two moveable contacts are prone to unreliable contact, causing that the receptacle type ground fault circuit interrupter cannot work normally.
In addition, as the power input connection assembly is very similar to the load connection assembly in the current GFCI, reverse connection of power supply wire and load wire often occurs during the installation and utilization. In that case, the GFCI acts only as a normal receptacle with no leakage protection function, and the hidden trouble of electric shock that may cause personal injury and property damage exists. For this reason, now many countries and regions require that, in case of reverse connection of the power supply line and load connection assembly, the receptacle type ground fault circuit interrupter should be unresettable and there should be no power output even when the reset key is pressed forcefully in order to prevent hidden safety trouble and to ensure personal and property safety.
The disclosed structure aims to overcome the shortage of the current technology and to provide a receptacle type ground fault circuit interrupter with simple structure, reliable contact and reverse wiring protection function.
A ground fault circuit interrupter for a receptacle having a power input side and a load side may comprise some or all of the following:
A reset key may have a pressing direction, the reset key comprising a reset locking mechanism having a motion trail that intersects with a central longitudinal axis of an electromagnetic tripping iron core. A reset mechanism may comprise a reset bracket comprising a first guide slot on a first side and a second guide slot on a second side. A bracket reset mechanism may comprise at least one support spring and a bracket homing mechanism that is biased to push the reset bracket in a sliding direction in to a first position. A reset linkage mechanism may be between the reset key and the reset bracket, the reset linkage mechanism may be configured to link a reset homing action and the sliding of the reset bracket. A reset linkage clutching mechanism may be configured to control the reset linkage mechanism when the interrupter resets. An electromagnetic tripping mechanism, may comprise a coil rack with a central hole, an electromagnetic tripping coil wound around the coil rack, the electromagnetic tripping iron core, and an iron core reset spring.
A conductive assembly may be configured from the power input side to the load side, the conductive assembly may be configured to selectively connect or disconnect electrical continuity between the power input side and the load side. The conductive assembly may comprise a pair of short-circuit conductive strips, each strip having a conductive movable contact. A pair of power input connection assemblies may each comprise an input conductive stationary contact configured opposite to the conductive movable contacts of the short-circuit conductive strips. The conductive assembly may comprise a pair of wiring output assemblies, a pair of receptacle output assemblies, each receptacle output assembly having an output stationary contact, and a first short-circuit conductor and a second short-circuit conductor between the pair of short-circuit conductive strips and the pair of receptacle output assemblies.
A reverse wiring protection device may comprise an electromagnetic generating device having a power supply sub-circuit configured with a reed switch connected in series. An electromagnetic actuator bracket may have a pair of conductive pads, each pad having a movable contact, configured to selectively electrically connect and disconnect to the pair of output stationary contacts. The reverse wiring protection device may comprise an actuator bracket homing mechanism, and a normally open holding switch connected in parallel with the reed switch, and linked with the electromagnetic actuator bracket.
The electromagnetic tripping iron core and the iron core reset spring may be positioned in the central hole of the coil rack with a clearance fit. The electromagnetic tripping iron core may be configured to slide perpendicular to the pressing direction of the reset key. The reset locking mechanism may fit with an end of the electromagnetic tripping iron core. The electromagnetic generating device may control the electromagnetic actuator bracket to selectively disconnect the movable contacts of the conductive pads from the pair of output stationary contacts.
Under the influence of one or more of the reset key, bracket reset mechanism, bracket homing mechanism, and the electromagnetic tripping mechanism, the reset bracket may be configured to slide between a first position and a second position to control the selectivity of the conductive assembly. The reset bracket may mounted to slide in a plane perpendicular to the pressing direction of the reset key.
One of the pair of short-circuit conductive strips may be held in the first guide slot of the reset bracket and the other of the pair of short-circuit conductive strips may be held in the second guide slot of the reset bracket so that when the reset bracket slides from the first position to the second position the movable contacts of the pair of short circuit conductive strips move from the first position that disconnects electrical continuity between the power input side and the load side to the second position that connects electrical continuity between the power input side and the load side. The conductive movable contacts may be configured respectively on the pair of short-circuit conductive strips facing the second position. The at least one support spring may be positioned between the reset bracket and the side of the short-circuit conductive strip without the conductive movable contacts.
The pair of power input connection assemblies may be on one side of the reset bracket and the pair of wiring output assemblies and the pair of receptacle output assemblies may be on a second side of the reset bracket. A portion of the pair of wiring output assemblies, through the second short-circuit conductor, at least one of the pair of conductive pads and at least one of the pair of the receptacle output assemblies, may be configured to form a selective electrical connection.
The actuator bracket homing mechanism may be configured to keep the movable contacts of the pair of conductive pads in a normally-closed state with the output stationary contacts of the pair of receptacle output assemblies.
At least a portion of the power supply sub-circuit of the electromagnetic generating device may bridge over the wiring output assembly, the reed switch of the power supply sub-circuit may link with the reset key, and the reed switch of the power supply sub-circuit may close in the tripped state and open in the reset state and in the resetting process.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention.
Reference will now be made in detail to the present exemplary embodiments, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
The receptacle type ground fault circuit interrupter includes reset key 4 and reset mechanism, conductive assembly from power input side to load side, leakage signal detection circuit, and electromagnetic tripping mechanism 15 acting as controlled by the leakage signal detection circuit. On reset key 4, reset latching mechanism matching with the end of electromagnetic tripping iron core 151 is provided. Between the said reset key 4 and reset bracket 12, the reset linkage mechanism linking the reset key homing action and the sliding of reset bracket 12 to Position 1 is provided. Also the reset linkage clutching mechanism is provided. The said reset linkage clutching mechanism controls the said reset linkage mechanism to link when the interrupter resets.
As shown in
The conductive assembly includes power input connection assembly 7, short-circuit conductive strip 8, wiring output assembly 9 and receptacle output assembly 10, which are provided in pairs. The first short-circuit conductor 11 is provided between the said short-circuit conductive strip 8 and receptacle output assembly 10 to form electrical connection, constituting electrical connection as shown in
The said reset mechanism includes reset bracket 12 and bracket homing mechanism. Under the action of reset key 4, bracket homing mechanism and electromagnetic tripping mechanism 15, the said reset bracket 12 has two positions, i.e. Position 1 in reset state (close state) and Position 2 in trip state (open state). The said reset bracket 12 controls the contact in the conductive assembly, thereby connecting or disconnecting the electrical connection from power input side to load side. As shown in
The pair of short-circuit conductive strips 8 are inserted in the slots 120 in the two sides respectively. The short-circuit conductive strips 8 are composed of strip-shaped sheets made of copper. A section of the short-circuit conductive strips 8 clearance-fit with slots 120, as shown in shape, a shape having a vertex between two arms set ninety degrees apart. The short-circuit conductive strips 8 are clasped in the corresponding slots 120 with horizontal clearance fitting, allowing them to be able to slide along the sliding direction of reset bracket 12.
In this embodiment, flexible conductive wires are provided for electrical connection between the short-circuit conductive strips 8 and receptacle output assembly 10. One flexible conductive wire is the first short-circuit conductor 11. The short-circuit conductive strip 8 is provided with conductive movable contact 801 in the downward-bending part at the upper end in the side facing Position 1. In a space between the side of the short-circuit conductive strip 8 other than the side with conductive movable contact 801 provided and the side of reset bracket 12, support spring 13 is provided as elastic support. At least one other support spring can be between the reset bracket 12 and a block 21. And, as shown in
As shown in
On the upper end face of block 21 above reset sliding block 22, spring cavity 220 is provided. Compression spring 24 and block 21, and reset sliding block 22, in sequence, are covered over reset pole 14, and at least compression spring 24 is movable. The lower end of compression spring 24 is placed in spring cavity 220 and pushes against the upper end face of block 21. The upper end of compression spring 24 pushes against a lower face of the reset pole 14, constituting reset mechanism of the said reset sliding block 22 and allowing reset sliding block 22 to have a force to slide toward the reset key pressing direction.
On the said reset sliding block 22 on a side close to reset pole 14, and facing outwardly with respect to reset pole 14, a triangular projecting block 141 is provided. Projecting incline 142 is provided at the upper end of projecting block 141. The direction of the said incline 142 is slantwise facing the homing direction of reset key 4 (i.e. is slantwise upward). On the said reset bracket 12 at the position corresponding to projecting incline 142, reset incline 121 is provided. The said reset incline 121 is located on the motion trail of projecting incline 142. The said reset incline 121 corresponds to the said projecting incline, and the slope matches (i.e. is slantwise downward). Between the said reset sliding block 22 and reset pole 14, reset linkage mechanism is provided. Of course projecting block 141 can also be of another shape, such as an arc, as long as it has an incline matching or complementing the inclined side wall of reset incline 121.
The reset mechanism of reset sliding block 22 functions, in the tripped state, to prevent the projecting incline 142 on reset sliding block 22 from interacting with the reset incline 121 of reset bracket 12 to make it possible to isolate the conductive assembly from the power input side to the load side.
In order that the reset bracket 12 could slide steadily, this receptacle type ground fault circuit interrupter is also provided with reset bracket seat 20. Between the said reset bracket and the reset bracket seat, guide mechanism is provided. As shown in
On the top of the vertical wall of reset bracket seat 20, horizontal sliding face is provided. On the horizontal sliding face at the end close to Position 2 of reset bracket 12, a pair of “┐”-shaped guide clips 201 are provided. The guide clips 201 comprise two arms at ninety degrees, with one arm parallel to the horizontal sliding face and the second arm perpendicular to the horizontal sliding face. The reset bracket 12 is provided slideably between the sliding face at the top of the reset bracket seat and the “┐”-shaped guide clip 201. In the side of the reset bracket 12 at the two sides of the reset incline 121, guide slots 122 clearance-fitting with guide clip 201 are provided. The pair of “┐”-shaped guide clips 201 are located in guide slot 122, constituting the guide mechanism for reset bracket 12.
At the other end of the horizontal sliding face, limit stop 202 is provided to limit the reset bracket 12 and to prevent the reset bracket 12 from sliding off. The limit stop 202 is generally of a long slat shape. On the reset bracket seat 20 in the end of the said horizontal sliding face close to Position 1 of reset bracket 12, a pair of vertical slots 203 are provided to match with the limit. The limit stop 202 is clearance-fit and inserted in the vertical slots 203, with the upper end exposed to form the limit. Between the upper end of the limit stop 202 and the said reset bracket 12, bracket reset spring 13 is provided so that reset bracket 12 could have a force to slide toward Position 2, constituting the bracket homing mechanism.
As shown in
The electromagnetic tripping iron core 151, with the step axial shape, is covered over by the iron core reset spring 153 and then is inserted slideably from the end close to reset pole 14 into the central axial hole of the tripping coil rack 154. The front end of electromagnetic tripping iron core 151 is exposed, and is of spherical shape. The motion trail of the said reset locking hole 401 along with the pressed reset key 4 intersects with the centerline of the said electromagnetic tripping iron core 151. The reset locking hole 401 clearance-fits with the end of the electromagnetic tripping iron core 151, forming the reset latching mechanism.
At the positions on the outer wall of the said reset sliding block 22 and the said reset locking hole 401 corresponding to the pressing motion trail of the reset key 4, linking holes 143 that penetrate to the internal hole are provided. The said linking hole 143 is sized to clearance-fit with the electromagnetic tripping iron core 151. The reciprocating end of the said electromagnetic tripping iron core 151 is located in the linking hole 143, constituting the said reset linkage clutching mechanism. In tripped state, the central axis of the said electromagnetic tripping iron core 151 corresponds to incline 402 at the lower part of reset pole 14 or below it. Under the action of the elastic force of iron core reset spring 153, the front end of the said electromagnetic tripping iron core 151 pushes against incline 402 at the lower part of reset pole 14 or below it. However, the distance from reset locking hole 401 to the centerline of electromagnetic tripping iron core 151 shall be no more than the stroke of reset key 4. Locating the reciprocating end of the said electromagnetic tripping iron core 151 in linking hole 143 is to satisfy the homing stroke of reset key 4 and to drive the said reset bracket 12 for resetting through the interaction between the said reset incline 121 and the incline of the said projecting incline. For this reason, in this embodiment as shown in
The reverse wiring protection device 99 includes electromagnetic generating device 161, electromagnetic actuator bracket 162, actuator bracket homing mechanism and holding switch 23. The said electromagnetic actuator bracket 162 is provided with a pair of conductive pads 164 & 165. At one end of the said conductive pads 164 & 165, movable contacts 166 & 167 are provided corresponding to the receptacle output stationary contacts 105 & 106 (i.e. K3 in
The said electromagnetic actuator bracket 162 is composed of insulation plates. A pair of conductive pads 164 & 165 are sandwiched in the insulation plates. Conductive pads 164 & 165 can be made as Z shape to facilitate improvement of elasticity and to improve contact reliability. Pivot is provided in the middle section of the insulation plate, forming a seesaw structure provided above the said electromagnetic generating device 161 and below middle frame 6. The insulation plate is also provided with armature, which is adjacent to the iron core. One end of the said pair of conductive pads 164 & 165 extends to below the left and right stationary pieces 103 & 104 on the left and right receptacle pads 101 & 102 respectively. The end movable contacts 166 & 167 of the conductive pads 164 & 165 correspond to the receptacle output stationary contacts 105 & 106. In this embodiment, between the other side of the pivot on the said electromagnetic actuator bracket 162 and one end of the mounting bracket of the electromagnetic generating device 161, tension spring 19 is provided to constitute the said actuator bracket homing mechanism, causing the said conductive pad movable contacts 166 & 167 to warp upwards and to contact with the receptacle output stationary contacts 105 & 106 thereby keeping in normally-closed state.
Between the other end of the said pair of conductive pads 164 & 165 and the wiring output assembly 9, the second short-circuit conductor 21 is provided to constitute electrical connection. So under the normal conditions, the conductive assembly from the power input side to the load side is composed of two groups of conductors. One group is power input connection assembly 7, and the other group includes short-circuit conductive strip 8, receptacle output assembly 10, conductive pad, short-circuit conductor and wiring output assembly 9. For the first short-circuit conductor 11 and the second short-circuit conductor 21, normally flexible conductors braided with fine copper wires are selected. In this embodiment, the reed switch 18 is provided at the bottom of base 1, and is composed of a pair of conductive reeds with contacts provided at the ends. The two conductive reeds are provided with one above another. The end of the lower conductive reed is just at the lower end of reset pole 14. Through hole is provided on the bottom of base 1 at the position corresponding to the lower end of reset pole 14. The lower end of reset pole 14, through the said through hole, is adjacent to the end of the conductive reed below, constituting the linkage with reset key 4. The holding switch 23 is connected in parallel with the reed switch 18. The holding switch 23 is a normally-open switch, and links with the electromagnetic actuator bracket.
The working status of holding switch 23 is reverse to that of the conductive pad movable contact and receptacle output stationary contact. That is to say, if the conductive pad movable contact and receptacle output stationary contact are closed, the holding switch 23 is open; if the conductive pad movable contact and receptacle output stationary contact are open, the holding switch 23 is closed.
As shown in
As shown in
The receptacle output assembly 10 is also provided with receptacle output stationary contacts 105 & 106. In this embodiment, the left and right receptacle pads 101 & 102 are provided respectively with left and right stationary pieces 103 & 104 extending to the center of base 1. Receptacle output stationary contacts 105 & 106 are provided on left and right stationary pieces 103 & 104. Wiring output assembly 9 is composed of two pieces of conductive wiring pieces 901 & 902 and screws 903 & 904. The two conductive wiring pieces 901 & 902 are inserted in the inner wall in the two sides of base 1. On the two side walls of base 1 at the positions corresponding to conductive wiring pieces 901 & 902, notch is provided, exposing conductive wiring pieces 901 & 902. The structure of power input connection assembly 7 is similar to that of wiring output assembly 9. It is also inserted in the inner wall in the two sides of base 1 at the other end. One end of power input connection assembly 7, through the mutual-inductive magnet ring, extends (or otherwise formed by connecting two sections of conductors) to near the lower end of short-circuit conductive strips 8. It is provided with power input conductive stationary contacts 701 & 702 to correspond to conductive movable contacts 801. Such structure of short-circuit conductive strips 8 makes the reset mechanism in reset state. Short-circuit conductive strips 8, in the rear side of conductive movable contacts 801, can be provided with elastic support such as springs. Therefore, even when the power input conductive stationary contacts 701 & 702 are not in a same plane accurately, short-circuit conductive strips 8 can adapt automatically to ensure reliable contact.
To facilitate assembly, the said reset bracket seat 20 can also be provided with horizontal sliding face only and with no ninety degree “┐”-shaped guide clips 201, while the other structure can be the same as that of the previously described embodiment. As shown in
In addition, in the reset latching mechanism, the reset locking hole 401 on reset key 4 is not the only structure to mate with electromagnetic tripping iron core 151. Alternatively, projecting reset hook 403 can be provided at the corresponding position on reset pole 14. Reset hook 403 can be made by punching, as shown in
The working principle of this receptacle type ground fault circuit interrupter is as follows: The circuit schematic diagram of this receptacle type ground fault circuit interrupter is shown in
When reset key 4 is pressed manually and resets, the pressure overcomes the elastic force of key reset spring 17, causing reset key 4 to move downwards. In the meantime, the front end of electromagnetic tripping iron core 151, under the action of the incline 402, causes electromagnetic tripping iron core 151 to retreat and to slide into reset locking hole 401. After the external force is withdrawn, under the action of the elastic force of key reset spring 17, reset key 4 together with reset pole 14 moves upward. Because the front end of electromagnetic tripping iron core 151 in inserted through linking hole 143 of reset sliding block 22 into reset locking hole 401, reset sliding block 22 links with reset pole 14 and moves upward. In this up-moving process, projecting incline 142 on reset sliding block 22 interacts with reset incline 121 and overcomes the elastic force of support spring 13, pushing reset bracket 12 to slide toward Position 1. This causes the power input conductive stationary contacts 701 & 702 to contact with conductive movable contacts 801 (K1 in
Also during the manual pressing of the reset key 4, reed switch 18 (S2 in
In case of reverse connection of the circuit in trip state, because the contact of reed switch 18 (i.e. S2 in
The reed of holding switch 23 (S3 in
Because the conductive assembly of the receptacle type ground fault circuit interrupter includes power input connection assembly, first short-circuit conductive strip, wiring output assembly, receptacle output assembly, second short-circuit conductive strip, a pair of conductive pads on the electromagnetic actuator bracket which are provided in pairs, and because the first short-circuit conductor and the second short-circuit conductor are provided between the wiring output assembly and receptacle output assembly to form electrical connection, the conductive assembly in normal time is composed of two groups of conductors, which realize electrical connection through the contact between the movable contacts on the short-circuit conductive strips and the stationary contacts on the receptacle output assembly, and the short-circuit conductive strips form elastic support with a spring.
During reset, due to the action of the elastic support component, the movable contact presses elastically on the stationary contact, ensuring contact pressure. So the contact resistance is lessened. Moreover, because the short-circuit conductive strips are supported elastically, even when the position of the stationary contacts are slightly deviated, the short-circuit conductive strips are self-adjustable and self-adaptable, thus improving the working reliability.
Through the above setting, when under normal (correct) wiring conditions and while in the trip state, no power supply is available on the wiring output assembly and the movable contacts on the conductive pads and the receptacle output stationary contact close. In the reset state, since the contact of the reed switch opens, no power supply is available on the power supply sub-circuit of the electromagnetic generating device, and the movable contact on the said conductive pad and the receptacle output stationary contact are also closed. Therefore, the conductive assembly is still composed of two groups of conductors.
In the case of reverse connection in the circuits, in a trip state, since the contacts of the reed switch close, the power supply sub-circuit of the electromagnetic generating device connected on the wiring output assembly obtains power supply and controls the electromagnetic actuator bracket to act, disconnecting the conductive pad movable contacts and the receptacle output stationary contacts, turning off the power in the receptacle output assembly, and allowing no power output in the receptacle sockets.
Meanwhile, since a reset linkage mechanism is provided between the reset key and the reset bracket to link the reset key homing action and the sliding of the reset bracket to Position 1 and also reset linkage clutching mechanism is provided, the reset linkage clutching mechanism controls the said reset linkage mechanism to link when the interrupter resets and the reset bracket slides to Position 1. The sliding reset is to be driven through the reset key homing action. It cannot be reset when the reset key is pressed continuously with external force. That is to say, the movable contacts of the conductive pads will not close with the receptacle output stationary contacts when there is a reverse wire. Therefore, in case of reverse wiring of the circuit, whether in tripped state or in the state where the reset key is continuously pressed, the conductive assembly from the power input side to the load side is always separated into two segments and no power is outputted from the receptacle sockets. So the reminding and safety protection functions are realized and the hidden trouble in safety is eliminated.
In the preceding specification, various preferred embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various other modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense.
Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the invention being indicated by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201110200616.X | Jul 2011 | CN | national |
| 201110262191.5 | Sep 2011 | CN | national |
| 201210024531.5 | Feb 2012 | CN | national |
