Description

CIRCUITS BREAKER HAVING RESETTING FUNCTION AND BREAKING FUNCTION FOR ABNORMAL CURRENT

Technical Field

[1] The present invention relates to a circuit breaker having a resetting function and a breaking function for an abnormal current. In the circuit breaker, when an abnormal current is generated at a load side, a detection/breaking unit interrupts a current supply by releasing the contact point between a fixed contact terminal and a movable contact terminal of a contact point unit. After a predetermined time elapses, the breaking resetting unit mutually contacts the movable contact terminal with the fixed contact terminal of the contact point unit. The breaking and resetting operations of the contact point unit can be automatically performed by the detecting/breaking unit and the breaking resetting unit. Therefore, the circuit breaker is easy to use and has the improved space efficiency due to its miniaturization, thereby increasing the competitiveness. Background Art

[2] A circuit breaker is a switching device that is provided between a power supply and a load side to interrupt a current flow from the power supply to the load side when an abnormal current is generated at the load side. Accordingly, the circuit breaker can prevent a safety accident that may occur due to the abnormal current.

[3] Such a conventional circuit breaker includes a case, a switch handle, a contact point unit, a breaking unit, and a control unit. The switch handle has a knob protruding outwardly from one side of the case and performs an on/off operation. The contact point unit is provided under the switch handle and interrupts a power and a current of a load side according to the on/off operation of the switch handle. The breaking unit is provided at one side of the contact point unit and forcibly interrupts a current flow of the contact point unit when an abnormal current occurs at the load side. The control unit includes a circuit for controlling the respective components of the circuit breaker.

[4] In addition, the contact point unit includes a power terminal, a load terminal, a fixed contact terminal, a movable contact terminal, a crossbar, a latch, and a trip bar. The power terminal and the load terminal are provided between both sides of the case. The fixed contact terminal and the movable contact terminal are provided between the power terminal and the load terminal to make or break a current flow by their mutual connection or disconnection. The crossbar is provided above the movable contact terminal, and the latch is provided above the crossbar. The trip bar is provided at one side of the latch to lock the latch.

[5] The breaking unit is provided at one side of the trip bar of the contact point unit, and a cable is connected to the load side. A zero phase current transformer (ZCT) is constructed at one side of the cable. Therefore, when an abnormal current occurs at the load side, the trip bar is pushed by the abnormal current.

[6] Further, the breaking unit is a breaking unit that is widely used in typical circuit breakers. The breaking unit may be classified into a mechanical breaking unit and a magnetic breaking unit, depending on a breaking method. The mechanical breaking unit uses a bimetal, and the magnetic breaking unit uses a magnetic element such as a solenoid. In the case of the mechanical breaking unit, when the bimetal is heated by the abnormal current, it is bent in one direction and pushes the trip bar. In the case of the magnetic breaking unit, the solenoid is magnetized by the abnormal current, and a plunger moves backward due to a magnetic field generated by the magnetization. Accordingly, a level is pivoted to push the trip bar.

[7] An operation of the conventional circuit breaker will be described below.

[8] When the knob of the switch handle, which protrudes at one side of the case, changes from an off position to an on position, the switch handle is pivoted to descend the latch provided under the switch handle. In addition, due to the descending of the latch, the crossbar and the movable contact terminal descend together, and the movable contact terminal comes in contact with the fixed contact terminal provided under the movable contact terminal. Thus, the power and the load side are electrically connected to each other.

[9] At this point, the crossbar is disposed on the top of one side of the movable contact terminal and the other side of the movable contact terminal is fixed. Due to the descending of the crossbar, the movable contact terminal has an elastic repulsive force against the pressing. In addition, when the latch is in a descended state, one side of the latch intermittently ascends due to the trip bar. Therefore, even though the elastic repulsive force of the movable contact terminal is applied, the crossbar and the latch maintain the descended state.

[10] Meanwhile, when the abnormal current occurs at the load side due to the electric connection during the use of the circuit breaker, the breaking unit operates in the mechanical or magnetic method and pushes the trip bar provided at one side thereof.

[11] In addition, the latch locked to the trip bar is released due to the pushing of the trip bar. The released trip bar ascends together with the crossbar due to the elastic repulsive force of the movable contact terminal. Further, the ascending of the movable contact terminal causes the contact of the fixed contact terminal to be released, so that the movable contact terminal is electrically disconnected from the fixed contact terminal.

[12] Further, the ascended latch forcibly rotates the switch handle from the on position to the off position in association with the switch handle.

[13] Therefore, the breaking unit breaks the contact point unit when the abnormal current occurs at the load side, thereby preventing the occurrence of the safety accident. When the factor of the abnormal current is removed, the user changes the switch handle from the off position to the on position.

[14] However, the mechanical circuit breaker using the bimetal has a slow response time with respect to an instantaneous abnormal current such as thunderstroke, surge, and overcurrent caused by short-circuit. Thus, the mechanical circuit breaker cannot adequately perform the breaking operation. In some cases, since the circuit breaker cannot be reused, it must be entirely replaced, leading to the increase of the maintenance cost.

[15] Further, the conventional circuit breakers have been widely used because they have a fast response time with respect to the abnormal current caused by the overcurrent. However, the circuit current frequently operates in response to a current slightly higher than the rate current. Therefore, the user is inconvenienced by having to manually reset the switch handle. This increases the power consumption, increasing the user's burden.

[16] Meanwhile, circuit breakers implemented with a resetting unit have been recently proposed. The resetting unit includes an additional resetting unit, such as a link, which is provided to a switch handle protruding at one side of a breaker case. When a breaking unit of the circuit breaker interrupts a current flow, the resetting unit performs a resetting operation to forcibly turn on the switch handle after a predetermined time elapses. Therefore, the fixed contact terminal and the movable contact terminal of the contact point unit are contacted with each other, thereby eliminating the user's inconvenience.

[17] When the abnormal current occurs due to the overcurrent such as short-circuit, the circuit breaker must keep on maintaining the off state. However, in this case, heat of the power line due to the continuous resetting operation of the resetting unit may cause a fire. Consequently, a more serious accident may happen.

[18] Further, the addition of the resetting unit increases a volume, causing degradation in the usage efficiency of the installation space. Especially, the increase in the number of parts and the number of operations decreases the product competitiveness because of high price.

Disclosure of Invention Technical Problem

[19] An object of the present invention is to provide a circuit breaker having a resetting function and a breaking function for an abnormal current, in which a breaking resetting unit is configured to selectively reset the contact point unit according to the factors of the abnormal current and thus the breaking and resetting operations are selectively

performed according to the factors of the abnormal current, thereby maximizing the usage convenience and efficiency of the circuit breaker.

[20] Another object of the present invention is to provide a circuit breaker having a resetting function and a breaking function for an abnormal current, in which a detecting/breaking unit and a breaking resetting unit are embedded into the circuit breaker and thus the circuit breaker can be miniaturized, thereby increasing the space efficiency and the product competitiveness. Technical Solution

[21] According to an aspect of the present invention, there is provided a circuit breaker having a resetting function and a breaking function for an abnormal current, the circuit breaker including: a switching unit; a contact point unit for breaking or contacting a power side and a load side according to on/off positions of the switching unit; a detecting/breaking unit for breaking the contact point unit when an abnormal current is detected at the load side; a control unit having a control circuit; and a breaking resetting unit provided at one side of the detecting/breaking unit to reset the switching unit and the contact point unit in response to a reset control signal outputted from the control unit. The detecting/breaking unit includes: a leakage detecting/breaking unit for detecting if the abnormal current occurring at the load side is derived from an external factor, including thunderstroke and surge, and breaking the contact point unit when the abnormal current is derived from the external factor; and a short-circuit detecting/ breaking unit for detecting if the abnormal current occurring at the load side is derived from an internal factor, including short-circuit, and breaking the contact point unit when the abnormal current is derived from the internal factor.

[22] Each of the leakage detecting/breaking unit and the short-circuit detecting/breaking unit of the detecting/breaking unit may include: a coil member having a cylinder with a hollow, and a coil wound around the cylinder; a shaft having one end inserted into the hollow of the coil member, and another end protruding outwardly, such that the shaft slides into the hollow when the coil member is magnetized; and a pivot member having a lower portion coupled to the other end of the shaft, a middle portion coupled to a hinge, and an upper portion rotating around the hinge when the shaft is sliding, such that the pivot member breaks a contact point of the contact point unit by a rotation force.

[23] The detecting/breaking unit may further include a bimetal configured to be heated by a high current higher than a rate current and bent in one direction to break the contact point of the contact point unit.

[24] The control unit transfers the reset control signal only when the contact point unit is interrupted by the breaking operation of the leakage detecting/breaking unit due to the

external factor, including the thunderstroke and the surge, and the breaking resetting unit resets the switching unit and the contact point unit.

[25] The breaking resetting unit may include: a solenoid; a plunger disposed at a center portion of the solenoid to slide due to magnetization of the solenoid; and a link member having one end coupled to one end of the plunger, and the other end coupled to the switching unit, such that the link member automatically resets the switching unit by the sliding of the plunger.

[26] According to another aspect of the present invention, there is provided a circuit breaker having a resetting function and a breaking function for an abnormal current, the circuit breaker including: a case having an opening at one side, a support vertically disposed at a center portion, a hinge insertion hole defined at an upper portion of the support, and an arc-shaped guide hole defined at a lower portion of the support; a switching unit having a through hole coupled to the hinge inserted into the support of the case, a body formed in a link hole at a lower portion, and a knob protruding outwardly through the opening at an upper portion of the body; a contact point unit provided under the switching unit, the contact point unit including: a latch ascending along the guide hole of the support; a link coupled between the latch and the link hole of the body; a crossbar provided under the latch; a trip bar vertically provided at one side of the support and having a lower portion pivotably coupled, the trip bar locking the latch when the latch descends; a movable contact terminal provided under the crossbar, the movable contact terminal being configured to descend by pressing of the crossbar and have an elastic repulsive force; a fixed contact terminal having one end contacting the movable contact terminal; and power and load terminals connecting both ends of the case and the fixed and movable contact terminals; a detecting/ breaking unit provided at one side of the contact point unit, the detecting/breaking unit including: a coil member having a cylinder with a hollow, and a coil wound around the cylinder; a shaft having one end inserted into the hollow of the coil member, such that the shaft slides into the hollow when the coil member is magnetized; and a pivot member having a lower portion coupled to the shaft, and a middle portion coupled to a hinge, such that the pivot member rotates around the hinge to providing a pushing force to push the trip bar of the contact point unit in one direction; a breaking resetting unit including: a solenoid provided at the other side of the contact point unit ; a plunger provided at a center portion of the solenoid to slide due to magnetization of the solenoid; and a link member coupled between the plunger and the link hole of the body of the switching unit; and a control unit provided inside the case and having a circuit for controlling the respective units.

[27] The detecting/breaking unit may be provided in plurality and include: a leakage detecting/breaking unit for detecting an abnormal current derived from an external

factor, including thunderstroke and surge; and a short-circuit detecting/breaking unit for detecting an abnormal current derived from an internal factor, including short- circuit.

[28] The detecting/breaking unit may further include a bimetal configured to be heated by a high current higher than a rate current and bent in one direction to break the contact point unit by pushing the trip bar in one direction due to the bending of the bimetal.

[29] The breaking resetting unit may perform the resetting operation only when the breaking unit receives the reset control signal from the control unit.

[30] The short-circuit detecting/breaking unit may include a zero phase current transformer for detecting the abnormal current.

[31] The circuit breaker may further include an adjusting member provided at the trip bar to adjust a distance from the bimetal. Advantageous Effects

[32] As described above, since the breaking resetting unit is configured to selectively reset the contact point unit according to the factors of the abnormal current, the breaking and resetting operations are selectively performed according to the factors of the abnormal current, thereby maximizing the usage convenience and efficiency of the circuit breaker.

[33] Further, since the detecting/breaking unit and the breaking resetting unit are embedded into the circuit breaker, the circuit breaker can be miniaturized, thereby increasing the space efficiency and the product competitiveness.

[34] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. Brief Description of the Drawings

[35] FIG. 1 is an exploded perspective view of a circuit breaker when a top case is disassembled according to an embodiment of the present invention.

[36] FIG. 2 is a cross-sectional view of the circuit breaker according to an embodiment of the present invention.

[37] FIG. 3 is a perspective view showing an assembly of a switching unit, a contact point unit, and a breaking resetting unit according to an embodiment of the present invention.

[38] FIG. 4 is an enlarged view illustrating the operation state of a detecting/breaking unit when the circuit breaker is in an on state according to an embodiment of the present invention.

[39] FIG. 5 is an enlarged view illustrating the operation state of a leakage or short- circuit detecting unit in the detecting/breaking unit.

[40] FIG. 6 is an enlarged view illustrating the operation state of a bimetal in the detecting/breaking unit.

[41] FIG. 7 is an enlarged view illustrating the off state of the breaking resetting unit.

[42] FIG. 8 is an enlarged view illustrating the reset state of the breaking resetting unit.

[43] DESCRIPTION OF THE SYMBOLS IN MAIN PORTIONS OF THE

DRAWINGS>

[44] 10: case 14: support

[45] 16: hinge 18: guide hole

[46] 20: switching unit 22: knob

[47] 24: body 27: link hole

[48] 30: contact point unit

[49] 34a, 34b: fixed and movable contact terminal

[50] 35: crossbar 36: latch

[51] 37: link 38: trip bar

[52] 40: detecting/breaking unit

[53] 42: leakage detecting/breaking unit

[54] 44: short-circuit detecting/breaking unit

[55] 46: bimetal 410: coil member

[56] 412: hollow 414: cylinder

[57] 416: coil 420: shaft

[58] 430: pivot member 50: breaking resetting unit

[59] 52: solenoid 54: plunger

[60] 56: link member

Best Mode for Carrying Out the Invention

[61] Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

[62] FIG. 1 is an exploded perspective view of a circuit breaker when a top case is disassembled, FIG. 2 is a cross-sectional view of the circuit breaker, and FIG. 3 is a perspective view showing an assembly of a switching unit, a contact point unit, and a breaking resetting unit.

[63] Referring to FIGs. 1 to 3, the circuit breaker includes a case 10, a switching unit 20, a contact point unit 30, a detecting/breaking unit 40, a breaking resetting unit 50, and a control unit. The switching unit 20 includes a knob 22 that protrudes out of the case 10. The contact point unit 30 is provided under the switching unit 20 to release/contact a fixed contact terminal 34a from/with a movable contact terminal 34b according to the

rotating direction of the switching unit 20. The detecting/breaking unit 40 is provided at an inner side of the case 10 to break the contact of the contact point unit 30 when an abnormal current occurs at a load side. The breaking resetting unit 50 is provided at the other side of the detecting/breaking unit 40 to reset the contact point unit 30 in response to a reset control signal outputted from the control unit. The control unit is provided at an inside of the case 10 and includes a circuit for controlling the respective components of the circuit breaker and transferring the reset control signal to the breaking resetting unit 50.

[64] The case 10 includes a top case 10a and a bottom case 10b. An opening 12 is formed in the top case 10a. The knob 22 of the switching unit 20 protrudes outwardly through the opening 12. The switching unit 20, the contact point unit 30, the detecting/ breaking unit 40, and the breaking resetting unit 50, and the control unit are provided in the bottom case 10b.

[65] In addition, supports 14 are vertically provided on either side of the central portion of the bottom case 10b and spaced apart from each other by a predetermined distance. One side of each of the supports 14 is fixed to the bottom case 10b.

[66] Further, a hinge 16 and a hinge insertion hole 16a are provided at an upper portion of the supports 14, such that a body 24 of the switching unit 20 is pivotably mounted, and an arc-shaped guide hole 18 is defined in a lower portion of the supports 14 to guide the crossbar of the contact point unit 30.

[67] The switching unit 20 includes the knob 22, the body 24, a through hole 26, and a link hole 27. The knob 22 protrudes outwardly through the opening 12 of the top case 10a. The body 24 is formed at a lower portion of the knob 22. The through hole 26 into which the hinge 16 is inserted is defined at an upper portion of the body 24. The link hole 27 is defined at a lower portion of the body 24.

[68] In addition, an insertion space 28 is defined in a side of the body 24, such that one end of a link member of the breaking resetting unit 50 is inserted into the insertion space 28. The link member of the breaking resetting unit 50 is coupled by a line inserted into the link hole 27.

[69] The contact point unit 30 includes a power terminal 32a, a load terminal 32b, the fixed contact terminal 34a, the movable contact terminal 34b, a crossbar 35, a latch 36, a link 37, and a trip bar 38. The power and load terminals 32a and 32b are provided on both ends of the case 10 and connected to the power and the cable for the load side, respectively. The fixed and movable contact terminals 34a and 34b are provided between the power terminal 32a and the load terminal 32b to make or break a current flow. The crossbar 35 is provided above the movable contact terminal 34b. The latch 36 has one side contacting the upper portion of the crossbar 35, and another side disposed at the support 14. The latch 36 ascends along the guide hole 18. The link 37 connects the

latch 36 to the link hole 27 of the body 24 of the switching unit 20, and supports the latch 36 and the switching unit 20 such that the latch 35 descends or ascends along the guide hole 18 according to the rotating direction of the switching unit 20, i.e., the on/ off positions of the switching unit 20. The trip bar 38 has one end pivotably fixed to the bottom case 10b and an upper end vertically erected, and locks the latch 36.

[70] Preferably, another end of the movable contact terminal 34b is hinged such that one end of the movable contact terminal 34b has an elastic repulsive force by the pressing of the crossbar 35.

[71] In addition, the contact point unit 30 is not limited to the above-described structure.

The contact point unit 30 may have any structure only if it can electrically connect or disconnect the power and the load side by the contact or release of the fixed contact terminal 34a and the movable contact terminal 34b according to the on/off operation of the switching unit 20.

[72] Further, an elastic member providing an elastic force is included in the latch 36 or the switching unit 20. Due to the elastic member, the latch rapidly ascends when an abnormal current occurs, so that the movable contact terminal 34b is rapidly disconnected from the fixed contact terminal 34a.

[73] The term "breaking" means that the movable contact terminal 34b is released or disconnected from the fixed contact terminal 34a, that is, the movable contact terminal 34b is separated from the fixed contact terminal 34a so that a current supply from a power supply to the load is interrupted. The resetting means that the fixed contact terminal 34a and the movable contact terminal 34b re-contact each other so that a current flows from the power supply to the load side.

[74] When an abnormal current generated at the load side is detected, the detecting/ breaking unit 40 interrupts the current flow from the power supply to the load side by releasing the movable contact terminal 34b from the fixed contact terminal 34a of the contact point unit 30.

[75] The detecting/breaking unit 40 includes a coil member 410, a shaft 420, and a pivot member 430. The coil member 410 includes a cylinder 414 with a hollow 40, and a coil 416 wound around the cylinder 414. The shaft 420 has one end portion inserted into the hollow 412 of the cylinder 414 of the coil member 410, and the other end portion protruding outwardly, so that the shaft 420 moves backward by a magnetic force generated from the coil 416. The pivot member 430 has one end portion connected to the other end portion of the shaft 420, and a middle portion hingedly fixed. Therefore, the pivot member 430 pivots around the hinge 440 by the backward movement of the shaft 420, and the other end portion of the pivot member 430 pushes the trip bar 38 of the contact point unit 30. Thus, the latch 36 locked to the trip bar 38 is released and the electric connection of the contact point unit 30 is broken.

[76] An elastic member is further provided at the shaft 420 whose one end is inserted into the hollow 412 of the cylinder 414. The elastic member simultaneously has both a compressive force and an elastic repulsive force due to the shaft 420 pulled by the magnetization of the coil member 410. When the magnetization of the coil member 410 disappears, the elastic repulsive force of the elastic member makes the shaft 420 move to the original position.

[77] In addition, the detecting/breaking unit 40 employs a solenoid principle that moves the plunger forward or backward by the magnetic field. In some cases, any unit can be used if only it has an operation relationship similar to the solenoid.

[78] Meanwhile, it is preferable that a plurality of detecting/breaking units 40 should be provided. Therefore, one of the detecting/breaking units 40 may be used as a leakage detecting/breaking unit 42 that breaks the contact point unit 30 due to external factors of an abnormal current such as thunderstroke or surge, and another may be used as a short-circuit detecting/breaking unit 44 that breaks the contact point unit 30 due to internal factors of an abnormal current such as a short-circuit.

[79] In addition, the leakage detecting/breaking unit 42 is connected in series between the power and the load and determines if an abnormal current such as thunderstroke or surge occurs.

[80] Further, the short-circuit detecting/breaking unit 44 includes a determining unit that determines if a signal obtained through a zero phase current transformer (ZCT) is an abnormal current such as a short-circuit. The determining unit outputs an abnormal current determining signal to an SCR and operates a trip coil serially connected to the SCR.

[81] Moreover, the detecting/breaking unit 40 further includes a bimetal 46 formed of metal pieces having different thermal expansion coefficients.

[82] The bimetal 46 is vertically provided at one side of the trip bar 38 of the contact point unit 30. A lower end portion of the bimetal 46 is fixed to the bottom case 10b. When a current higher than a rate current set in the control unit occurs, that is, a high current ranging from 150% to 250% of the rate current occurs, the bimetal 46 is bent by heat and one end of the bent bimetal 46 pushes the trip bar 38 in one direction, thereby breaking the contact point unit 30.

[83] In addition, an adjusting member 39 is provided between the bimetal 46 and the trip bar 38. The adjusting member 39 adjusts a distance within which the pushing force is applied to the trip bar 38 by the bending of the bimetal.

[84] In other words, the detecting/breaking unit 40 detects the factors of the abnormal current, which may occur at the load side, e.g., electric leakage, short-circuit, and high current higher than the rate current, and operates the leakage detecting/breaking unit, the short-short detecting/breaking unit, and the bimetal.

[85] Preferably, the breaking resetting unit 50 is provided at the other side of the detecting/breaking unit 40. The breaking resetting unit 50 includes a solenoid 52, a plunger 54, and a link member 56. The plunger 54 has one end inserted into the solenoid 52, and the other end protruding outwardly. The plunger 54 moves backward by the magnetization of the solenoid 52. The link member 56 has one end fixed to the other end of the plunger 54, and the other end link- fixed to the link 37 inserted into the link hole 27 formed in the body 24 of the switching unit 20.

[86] In particular, the breaking resetting unit 50 performs the resetting operation only when the automatic reset breaker is turned on by the breaking operation of the leakage detecting/breaking unit 42.

[87] The reason for this is as follows: in the case of the short-circuit or high current, if the breaking resetting unit continuously performs the resetting operation after it is turned on when the abnormal current occurs at an electronic device or load side, the current from the power supply is continuously supplied to the load side; therefore, a current excessively flows into the electronic device or cable, so that the circuit breaker becomes useless.

[88] The control unit is provided in the inside of the case 10 and controls the respective components of the circuit breaker. In particular, when the leakage detecting/breaking unit 42 operates by the abnormal current such as thunderstroke or surge, the control unit transfers the reset control signal to the breaking resetting unit 50 after a predetermined time elapses, and the breaking resetting unit 50 resets the contact point unit 30. Since this is well known to those skilled in the art, its detailed description will be omitted and it is not shown in the drawings.

[89] Although not shown, it is also apparent that the circuit breaker may include a test unit that can determine if the automatic reset breaker 1 is installed and well operated.

[90] An operation of the circuit breaker will be described below.

[91] The switching unit 20 is provided inside the case 10, and the contact point unit 30 is provided under the switching unit 20. The detecting/breaking unit 40 is provided at one side of the contact point unit 30, and the breaking resetting unit 50 and the control unit are provided at the other side of the contact point unit 30. The cables are connected to the power terminal 32a and the load terminal 32b. Then, the knob 22 of the switching unit 20 changes from the off position to the on position, so that the current from the power supply flows into the load side.

[92] In this state, when an abnormal current occurs at the load side, the detecting/ breaking unit 40 operates to break the contact point unit 30, thereby interrupting the current flow from the power supply to the load side.

[93] FIGs. 4 to 6 are enlarged views illustrating the operation of the detecting/breaking unit according to an embodiment of the present invention. More specifically, FIG. 4 il-

lustrates an on state of the automatic reset breaker, FIG. 5 illustrates an operation state of the leakage or short-circuit detecting unit, and FIG. 6 illustrates an operation state of the bimetal.

[94] Referring to FIGs. 4 to 6, in case where the abnormal current is an overcurrent caused by an external factor such as thunderstroke or surge, when a detected current caused by the abnormal current is inputted to the leakage detecting/breaking unit 42 of the detecting/breaking unit 40, the detected current flows into the coil 416 of the coil member 410 so that the coil 416 is magnetized.

[95] In addition, due to the magnetization of the coil 416, the cylinder 414 around which the coil 416 is wound is magnetized. Due to the magnetization of the cylinder 414, the shaft 420 having one end inserted into the hollow 412 of the cylinder 414 moves backward.

[96] Further, due to the backward movement of the shaft 420, a lower end of the pivot member 430 is coupled to one end of the shaft 420. The lower portion of the pivot member 430 moves backward around the hinge 440, and the upper portion of the pivot member 430 has a forward rotation force and pushes the trip bar 38 provided at one side of the pivot member 430.

[97] Moreover, the trip bar 38 receiving the pushing force releases the locking of the latch 36, one side of which is locked to the trip bar 38 due to the rotation force of pushing the upper portion around the lower portion pivotably fixed.

[98] Meanwhile, due to the elastic repulsive force of the movable contact terminal 34b, the movable contact terminal 34b ascends and the crossbar 35 and the latch 36 ascend together.

[99] Therefore, due to the ascending of the fixed contact terminal 34b, the contact with the fixed contact terminal 34a is released to interrupt the current flow from the power supply to the load side.

[100] The ascending latch 36 is fit to the guide hole 18 of the support 14 through the lower side of the link 37. Therefore, the latch 37 ascends the link 37 along the guide hole 18.

[101] In addition, the upper portion of the link 37 is fit to the link hole 27 of the body 24 of the switching unit 20, and the link member 56 of the breaking resetting unit 50 is fit to the link hole 27. Therefore, due to the ascending force of the link 37, the body 24 of the switching unit 20 rotates around the hinge 16 coupled to the through hole 26.

[102] Further, the switching unit 20 forcibly changes from the on position to the off position, and the link member 56 connected to the body 24 of the switching unit 20 moves forward. The plunger 54 coupled to the other side of the link member 56 maintains the forwardly moved state.

[103] The leakage detecting/breaking unit 42 of the detecting/breaking unit 40 releases

the contact of the fixed and movable contact terminals 34a and 34b. Hence, the abnormal current occurring at the load side does not flow to the power side or another load side. As the switching unit 20 forcibly changes from the on position to the off position, the user can verify the state of the automatic reset breaker 1.

[104] Meanwhile, the leakage detecting/breaking unit 42 is operated by the abnormal current such as thunderstroke or surge, and the contact point unit 30 is interrupted. After a predetermined time elapses, the control unit transfers the reset control signal to the breaking resetting unit 50.

[105] FIGs. 7 and 8 are enlarged views illustrating the operation states of the breaking resetting unit according to an embodiment of the present invention. More specifically, FIG. 7 illustrates the off state of the breaking resetting unit, and FIG. 8 illustrates the reset state of the breaking resetting unit.

[106] Referring to FIGs. 7 and 8, the solenoid 52 is magnetized by the reset control signal, the plunger 54 moves backward by the magnetized solenoid 52, and the link member 56 fixed to one end of the plunger 54 moves backward by the pulling force.

[107] The other end of the link member 56 is link-coupled to the body 24 of the switching unit 20 through the link 37, and the body 24 rotates around the hinge 16 by the pulling force of the link member 56.

[108] In other words, the knob 22 of the switching unit 20 resets from the off position to the on position.

[109] In addition, the latch 36 and the other end of the link 37 link-coupling the body 24 and one end of the link member 56 are coupled to the guide hole 18 of the support 14. Due to the pulling force of the link member 56, the link 37 is pulled. The other end of the link 37 descends along the guide hole 18 and the latch 36 also descends.

[110] Due to the descending latch 36, the crossbar 35 disposed under the latch 36 and the movable contact terminal 34b disposed under the crossbar 35 descend. Thus, the movable contact terminal 34b comes in contact with the fixed contact terminal 34a disposed under the movable contact terminal 34b, so that the power and the load side are electrically connected to each other.

[I l l] One end of the descended latch 36 is locked by the trip bar 38, so that the arbitrary ascending of the latch 36 is prevented. In this way, the resetting operation of the breaking resetting unit 50 is completed.

[112] Meanwhile, when the abnormal current is an overcurrent caused by internal factors such as short-circuit, the abnormal current is detected by the zero phase current transformer of the short-circuit detecting/breaking unit 44. The detected current flows into the coil 416 of the coil member 410 and thus the coil 416 is magnetized.

[113] Since the subsequent operations of the short-circuit detecting/breaking unit 44 is equal to those of the leakage detecting/breaking unit 42, their detailed description will

be omitted.

[114] The contact point unit 30 is interrupted by the breaking operation of the short- circuit detecting/breaking unit 44, and the control unit does not transfer an additional reset control signal to the short-circuit detecting/breaking unit 44. The short-circuit detecting/breaking unit 44 maintains the off state until the knob 22 of the switching unit 20 is manually reset to the on position.

[115] Meanwhile, when the abnormal current is high current ranging from 150% to 300% of the rate current, the high current heats the bimetal 46 of the detecting/breaking unit 40 and thus the bimetal 46 is bent.

[116] The bent bimetal 46 pushes the trip bar 38 in one direction. The locking of the latch

36, one end of which is locked the trip bar 38, is released. Therefore, the crossbar 35 and the movable contact terminal 34b disposed under the latch 36 ascend, thereby disconnecting the power from the load side.

[117] When the internal factors such as short-circuit and high current are removed in such a state that the power and the load side are electrically disconnected by the contact point unit 30, the power and the load side can be electrically connected by resetting the knob 22 from the off position to the on position.

[118] In other words, the body 24 integrally formed with the knob 22 rotates around the hinge 16, and the link member 56 coupled to one end of the link 37 at the link hole 27 of the body 24 forcibly moves forward by the rotating force. The plunger 54 coupled to the other end of the link member 56 moves forward.

[119] In addition, the link 37 descends due to the rotation of the body 24, and the other end of the link 37 descends along the guide hole 18 and the latch 36 coupled to the other end of the link 37 descends.

[120] Further, as the crossbar 35 and the movable contact terminal 34b disposed under the descending latch 36 descend, the movable contact terminal 34b comes in contact with the fixed contact terminal 34a, so that the power and the load side are electrically connected to each other.

[121] Therefore, the contact point unit is interrupted by operating the detecting/breaking unit according to the factors of the abnormal current occurring at the load side. In some cases, the circuit breaker can be automatically reset, thereby improving the convenience of usage.

[122]