Abstract:
A circuit breaker having a mechanical trip mechanism enabling a circuit breaker to perform an emergency manual trip operation is provided. The circuit breaker includes: a fixed contactor connected to a circuit; a movable contactor movable to a closed state in which the movable contactor is in contact with the fixed contactor and a broken state in which the movable contactor is separated from the fixed contactor, an opening and closing mechanism configured to convert a rotational motion of a plurality of links and a rotational shaft to enable the movable contactor to be brought into contact with the fixed contactor or separated therefrom; a trip latch locked to or unlocked from a main link provided in the opening and closing mechanism; and an OFF button configured to rotate the trip latch to unlock the trip latch from the main link when manually pressed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority under 35 U.S.C. §119(a) to Korean Patent Application No. 10-2011-0147818, filed on Dec. 30, 2011, the contents of which are hereby incorporated by reference herein in their entirety. 
     BACKGROUND 
     1. Field of the Invention 
     The present invention relates to a circuit breaker and, more particularly, to a circuit breaker having a mechanical trip mechanism enabling a circuit breaker to perform an emergency manual trip operation. 
     2. Description of the Related Art 
     In general, a circuit breaker is a device for selectively turning on or off or breaking a line between a power side and a load side in the occurrence of an overload, a short-circuit fault, an electric leakage, or an electric shock. 
       FIGS. 1 ,  2 , and  3  illustrate a broken (trip) state (or an open state), a charged state, a closed (conducted) state of the related art circuit breaker. 
     In the related art circuit breaker, a user may press an OFF button  6  to manually perform a breaking operation, or when a fault current is detected, a circuit is automatically broken (a trip operation) to change the circuit breaker into a broken state. 
     In the case of the manual breaking operation, as illustrated in  FIG. 3 , when the user presses the OFF button  6  in a closed state, an OFF plate (not shown) is horizontally moved to the left in  FIG. 3  to rotate an OFF shaft  4  in a clockwise direction to start a breaking operation of the circuit breaker. 
     In case of an automatic trip for interrupting a fault current in a circuit, an overcurrent trip relay installed outside an opening and closing mechanism  10  detects a fault current and transmits a trip control signal to an actuator, and the OFF shaft  4  is rotated in a clockwise direction by the actuator to start a breaking operation. 
     No matter whether it is manual or automatic trip, when the OFF shaft  4  is rotated in the clockwise direction, a trip latch  7  is rotated in a clockwise direction so as to be released from a restrained state with respect to a main link  9  (or the trip latch  7  is rotated in a clockwise direction so as to be unlocked from the main link  9 ), and a breaking spring  2 , which has been stretched in the closed state to charge elastic energy, discharges the elastic energy to pull a connection shaft  21  connected to one end portion of the breaking spring  2  to rotate it in a counterclockwise direction. Accordingly, the opening and closing shaft  20  is also rotated in the counterclockwise direction and the connection link is moved to the right in  FIG. 3  to pull a movable contactor  30  to the right, and the movable contactor  30  is separated from the fixed contactor  40 , thus completing a manual breaking operation or automatic trip operation to electrically break the circuit. 
     In relation to the trip operation,  FIGS. 4 and 5  are detailed views illustrating an operational relationship among the OFF shaft  4 , the trip latch  7 , and the main link  7  within the opening and closing mechanism  10  of the related art circuit breaker. In case of a circuit breaker that normally operates, the user may press the OFF button  6  to manually break the circuit breaker, or in case of a trip operation of the circuit breaker by an automatic trip executed when a fault current occurs, the OFF shaft  4  disposed on an upper portion of the opening and closing mechanism  10  is rotated in the clockwise direction. In the closed state, the trip latch  7  receiving a contact load (applied by the main link  9 ) in a contact portion  97  of the main link  9  and a trip latch roller  73  is rotated in the clockwise direction so as to be released (or unlocked) from the main link  9 , and the contact load maintained in the contact portion of the main link  9  and the trip latch roller  73  in the closed state is changed into an open load, and as the open load is applied to the trip latch roller  73 , a trip operation is substantially performed. 
     However, although the user presses the OFF button  6  so the OFF shaft  4  is rotated, if the trip latch  7  is not rotated in the clockwise direction and is not released from the main link  9 , a trip operation of the circuit breaker is not actually performed, so a fault current cannot be interrupted. 
     Similarly, in the occurrence of an abnormal current, although the OFF shaft  4  is operated according to an automatic trip operation, if the trip latch  7  is not rotated in the clockwise direction due to several abnormal factors, the trip latch  7  is not released from the main link  9 , resulting in failure of interrupting the fault current. 
     Thus, a circuit breaker that may reliably be changed into a broken state to cut off an electrical connection in the occurrence of an abnormal state in which the circuit breaker is not tripped in a manual manner or an auto-trip manner is required. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention provides a circuit breaker having a mechanical trip mechanism for allowing for an emergency manual trip operation in an abnormal state in which the circuit breaker is not tripped in a manual manner or auto-trip manner. 
     According to an aspect of the present invention, there is provided a circuit breaker including: a fixed contactor connected to a circuit; a movable contactor movable to a closed state in which the movable contactor is in contact with the fixed contactor and a broken state in which the movable contactor is separated from the fixed contactor, an opening and closing mechanism configured to convert a rotational motion of a plurality of links and a rotational shaft to enable the movable contactor to be brought into contact with the fixed contactor or separated therefrom; a trip latch locked to or unlocked from a main link provided in the opening and closing mechanism; and an OFF button configured to rotate the trip latch to unlock the trip latch from the main link when manually pressed. 
     According to an embodiment of the present invention, when an auto-trip operation is not possibly performed in an abnormal state, mechanical trip mechanism performs an emergency manual trip operation to reliably change the circuit breaker into a broken state. Also, a condition in which the circuit breaker is not changed into a broken state by a manual operation is basically prevented, thus obtaining stability and reliability. 
     The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view illustrating a broken state of the related art circuit breaker; 
         FIG. 2  is a side view illustrating a charged state of the related art circuit breaker; 
         FIG. 3  is a side view illustrating a closed state of the related art circuit breaker; 
         FIG. 4  is a detailed view of a trip operation by an OFF shaft and a trip latch in the related art circuit breaker; 
         FIG. 5  is a detailed view of a trip operation by a trip latch and a main link in the related art circuit breaker; 
         FIG. 6  is a perspective view of a trip latch assembly installed in an opening and closing mechanism of the related art circuit breaker; 
         FIG. 7  is a perspective view of an OFF button installed in the opening and closing mechanism of the related art circuit breaker; 
         FIG. 8  is a perspective view of an OFF button of a circuit breaker according to a first embodiment of the present invention; 
         FIG. 9  is a perspective view of a trip latch assembly of the circuit breaker according to the first embodiment of the present invention; 
         FIG. 10  is a perspective view of an OFF button of a circuit breaker according to a second embodiment of the present invention; and 
         FIGS. 11 and 12  are detailed views of a trip operation by the OFF button and the trip latch assembly of the circuit breaker according to the first embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, a mechanical trip mechanism of a circuit breaker according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 
     The circuit breaker includes an opening and closing mechanism  10  converting a rotational motion of a plurality of links and a rotational shaft to compress a closing spring  1  and generating driving force according to elastic restoring force of the closing spring  1 , an opening and closing shaft  20  connected to an opening and closing mechanism and transmitting driving force generated by the opening and closing mechanism, a fixed contactor  40 , a movable contactor  30  movable to a closed state in which the movable contactor  30  is in contact with the fixed contactor  40  and a broken state in which the movable contactor  30  is separated from the fixed contactor, an overcurrent trip relay (not shown) outputting a control signal to trip the opening and closing mechanism  10  when an abnormal current is generated, and an actuator (not shown) for tripping the opening and closing mechanism by a control signal from the overcurrent trip relay. The configuration of the circuit breaker is the same as that of the related art circuit breaker, so a detailed configuration and operation thereof will be omitted. 
       FIGS. 6 and 7  are perspective views of an OFF button and a trip latch provided in the related art circuit breaker. As illustrated in  FIG. 6 , in an assembly of a trip latch  7 , two trip latches placed to be parallel in a length direction are coupled by a connection pin  71 . 
     A rotational shaft  72  of the trip latch is installed to penetrate the assembly of the trip latch  7 , and a trip latch roller  73  is provided between the rotational shaft  72  and one connection pin  71 . As can be seen in  fig. 7 , a reinforcing unit  62  is provided in a body frame  61  of an OFF button  6  on a rear surface of the OFF button  6 . The OFF button is supported to be rotatable at a predetermined angle by a button support  64  installed to penetrate an opening  63  formed in the reinforcing unit  62 . 
     In a closed state of the circuit breaker, the main link  9  and the trip latch  7  are locked, a contact load is applied to a contact portion  97  of the main link  9  and the trip latch roller  73 , and a locked state of the main link  9  and the trip latch roller  73  is maintained. When the circuit breaker is changed from a closed state to a broken state, the trip latch roller  73  is released from a state of being locked to the main link  9 , a contact load is changed into an open load, and the open load is applied to the trip latch roller  73  by the main link  9 . 
     When the circuit breaker normally operates, the OFF shaft  4  in an upper portion of the opening and closing mechanism  10  is rotated in a clockwise direction according to a manual and auto-trip operation, and accordingly, the trip latch  7  is rotated in a clockwise direction based on the rotational shaft  72  of the trip latch  7 , and thus, the trip latch roller  73  locked in the main link  9  is released. Thus, in order for the circuit breaker to be actually changed from the closed state to the broken state, the trip latch  7  should be rotated in the clockwise direction based on the rotational shaft  72  of the trip latch  7  to release the trip latch roller  73  locked in the main link  9 . 
     Hereinafter, the mechanical trip mechanism of the circuit breaker according to an embodiment of the present invention will be described in detail. 
     First, a configuration of the mechanical trip mechanism of the circuit breaker according to an embodiment of the present invention will be described. 
     In  FIGS. 8 and 9 , the OFF button  6  and the trip latch  7  according to a first embodiment of the present invention including the mechanical trip mechanism are illustrated. The mechanical trip mechanism includes a lever member  65  formed in the OFF button  6  and a protrusion member  75  coupled to the trip latch  7 . The lever member  65  and the protrusion member  75  are in a relationship of an operating unit and an operated unit that directly rotate the trip latch  7  in the clockwise direction when a user presses the OFF button  6  in order to change the circuit breaker into a broken state. 
     As illustrated in  FIG. 9 , the lever member  65  provided on a rear surface of the OFF button  6  is provided in the reinforcing unit  62  of the OFF button having an opening  63  through which a button support pin  64  is inserted. Preferably, the lever member  65  is integrally formed with the OFF button  6 . The lever member  65  integrally formed in a body frame  61  of the OFF button  6  is protruded to have a certain length such that it is parallel to a length direction of the trip latch  7 . The lever member  65  has a rectangular parallelepiped shape overall, and a front end portion  66  of the lever member  65  has a curved surface. In general, an ON button (not shown) and the OFF button  6  installed on a front portion of the circuit breaker and manually operated by the user are installed to be supported by a button support pin  64  penetrating the opening  63  of the OFF button  6 . Thus, when the user presses the button, the OFF button is rotatable within a predetermined angle range based on the button support pin  64 . 
     As illustrated in  FIG. 8 , the protrusion member  75  of the trip latch  7  is provided on one surface of the trip latch  7 . The protrusion member  75  of the trip lath  7  is protruded to have a predetermined length toward the lever member  65  of the OFF button  6  along an axial line direction of the rotational shaft  72  of the trip latch  7 . As for the length of the protrusion member  75 , the protrusion member  75  is protruded to slightly exceed the lever member  65  of the OFF button in a state of being installed in the opening and closing mechanism. Thus, when the OFF button is rotated based on the button support pin  64  as the user presses the OFF button  6 , the front end portion  66  of the lever member  65  rotated together according to the rotation of the OFF button reliably pressurizes the side of the protrusion member  75 . 
     The protrusion member  75  may be integrally formed with the trip latch  7  or may be separately formed and coupled to the trip latch  7 . When the protrusion member  75  is separately formed, the protrusion member  75  may be coupled to the trip latch  7  according to a certain method known in the art. For example, the protrusion member  75  may be coupled to the trip latch  7  according to a coupling method such as welding, caulking coupling, bolt fastening, or the like. 
     Referring to  FIG. 10 , an OFF button  6  according to a second embodiment of the present invention including a mechanical trip mechanism is illustrated. In the second embodiment, the lever member  65  is formed on the body frame  61  of a rear surface of the OFF button  6 . Unlike the first embodiment as described above, the lever member  65  according to the second embodiment includes a first lever unit  65   a  and a second lever unit  65   b . The first lever unit  65   a  extends to be parallel to a length direction of the trip latch  7 , and the second lever unit  65   b  is protruded from an end portion of the first lever unit  54   a  toward the trip latch  7  such that it is parallel to the rotational shaft of the trip latch  7 . In order to allow the second lever unit  65   b  to rotate the trip latch  7  in a clockwise direction, the second lever unit  65   b  has a length sufficient to simultaneously press one edge portion  75  of the trip latch  7  or both edge portions of the trip latch  7  of the trip latch assembly. Also, in the second embodiment, preferably, the lever member  65  is integrally formed with the OFF button  6 . However, the second lever unit  65   b  of the lever member  65  may be separately formed and coupled. 
     In the case of the second embodiment illustrated in  FIG. 10 , the lever member  65  provided in the OFF button  6  and having the first lever unit  65   a  and the second lever unit  65   b  has both the functions of the mechanical trip mechanism of the lever member  65  provided in the OFF button  6  and the protrusion member  75  provided in the trip latch  7 . Namely, the second lever unit  65   b  of the lever member  65  according to the second embodiment of the present invention corresponds to the protrusion member in the first embodiment as described above. Thus, in the second embodiment, when the lever member  65  is rotated as the OFF button  6  is pressed, the second lever  65   b  of the lever member  65  directly presses the edge portion  74  of the trip latch  7  to rotate the trip latch  7  in a clockwise direction based on the rotational shaft  72  of the trip latch  7 . 
     Hereinafter, an operation of the mechanical trip mechanism in the circuit breaker according to an embodiment of the present invention will be described. 
       FIGS. 11 and 12  are detailed views illustrating a trip operation of the circuit breaker by the OFF button  6  and the trip latch  7  having the mechanical trip mechanism according to an embodiment of the present invention, and the mechanical trip mechanism corresponds to the first embodiment including the lever member  65  of the OFF button and the protrusion member  75  of the trip latch  7 . 
     In the circuit breaker according to an embodiment of the present invention, when the user manually presses the OFF button  6  provided on a front portion of the circuit breaker, the OFF button rotates based on the button support pin  64 . At the same time, the lever member  65  of the OFF button is rotated. Thus, as shown in  FIG. 11 , the front end portion  66  of the lever member is brought into a lateral surface of the protrusion member  75  provided in the trip latch  7  to pressurize the trip latch  7 . Subsequently, in a continuous process, as shown in FIG.  12 , the lever member  65  continuously pressurizes the protrusion member  75  of the trip latch  7 , and thus, the trip latch  7  is rotated in a clockwise direction. Accordingly, the trip latch roller  73  locked in the main link  9  is released, and a contact load maintained in the contact portion  97  of the main link  9  and the trip latch roller  73  in the closed state of the circuit breaker is changed into an open load and transmitted to the trip latch roller  73 . Accordingly, the trip operation of the circuit breaker is certainly, reliably executed. 
     Also, in the second embodiment, similarly, when the OFF button  6  is operated manually, the second lever unit  65   b  of the lever member  65  provided in the OFF button  6  directly pressurizes the edge portion  74  of the trip latch  7 , and thus, the trip latch  7  is rotated in the clockwise direction. As the trip latch  7  is rotated in the clockwise direction, the trip latch roller  73  locked in the main link  9  is released, thus executing a trip operation of the circuit beaker. 
     As described above, in the circuit breaker according to an embodiment of the present invention, since the OFF button  6  includes the mechanical trip mechanism as an emergency manual trip means, the trip latch  7  can be directly rotated in the clockwise direction in association with an operation of the OFF button  6  to release the trip latch roller  73  locked in the main link  9 . Thus, even when an auto-trip operation is not possibly performed in an abnormal situation, the circuit breaker can be change into a broken state through the emergency manual trip operation. In addition, a situation in which the circuit breaker is not changed into a broken state through a manual operation is fundamentally prevented. 
     As the present invention may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.