Abstract:
A time delay output apparatus for a circuit breaker includes a switch disposed at one side of a main shaft rotatable in directions to open/close a fixed contactor and a movable contactor, and a delay member disposed between the main shaft and the switch so as to operate the switch with a preset time delay, thereby simplifying the construction and reducing the size as well as enhancing operational reliability by stably obtaining a time delay.

Description:
RELATED APPLICATION 
     The present disclosure relates to subject matter contained in priority Korean Application No. 10-2007-0070278, filed on Jul. 12, 2007, which is herein expressly incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a time delay output apparatus for a circuit breaker, and more particularly, to a time delay output apparatus for a circuit breaker which is capable of preventing a malfunction caused by vibration, by excluding the use of a mass, thereby enhancing the operational reliability. 
     2. Description of the Background Art 
     In general, a circuit breaker is an protective electrical device disposed between a power source and a load equipment so as to protect the load equipment and an electrical line from a circuit fault (e.g., a large current due to a short circuit, earth fault, etc.) which may occur in an electrical circuit. 
     Some circuit breakers are provided with a relay performing an MCR (Making Current Release) function, which sets a current value, detects the introduced current, and instantaneously opens the circuit breaker when a large current greater than a reference value is introduced, thus to prevent the flow of the large current into the load side. 
     The relay blocks the electrical line within a preset allowable delay time. When the circuit breaker is closed to check whether or not a fault occurred in the electrical line, and if the fault is not completely solved, a large fault current flows for the preset allowable time in the electrical line, thereby causing damage in the electrical line and the load. When the circuit breaker is closed to check whether or not a fault occurred in the electrical line, and if a main contact is contacted and thus a fault current is detected, there is a need to instantaneously open the circuit breaker without maintaining the allowable (delay) time preset on the relay in order to reduce damage in the electrical line and the load. Such function is called the “MCR” function. 
     In order for the relay to perform the MCR function, two cases should be distinguished: one case is where the fault current is blocked (i.e., a fixed contactor and a movable contactor are separated) when the circuit breaker is closed, and another case is where the fault current is blocked (i.e., the fixed contactor and the movable contactor contact each other) when the circuit breaker is closed on an electrical line where the circuit breaker had been opened due to a previously occurred fault. In order to distinguish such two cases, there is provided a time delay output apparatus for a circuit breaker, which outputs a contact signal with a certain delay time after the fixed contactor and the movable contactor contact each other. 
     As shown in  FIGS. 1 and 2 , the time delay output apparatus for a circuit breaker includes a switch  20  disposed at one side of a main shaft  10  so as to output a signal when a contact is detected, a delay plate  30  disposed pivotably with respect to a detection portion of the switch  20  so as to contact and be separated from the detection portion of the switch  20 , and a lever  12  integrally formed with the main shaft  10 , and pressing and pivoting the delay plate  30  so as to be separated from the switch  20  when the main shaft  10  is rotated in an opening direction. 
     The delay plate  30  includes a pivot shaft  31 , a first arm  33  extending from the pivot shaft  31  to the main shaft  10  and contacting the lever  12 , and a second arm  35  extending from the pivot shaft  31  to the switch  20  and contacting the detection portion of the switch  20  by being pivoted together with the first arm  33 . A spring  37  is connected to the second arm  35  so as to apply an elastic force in a direction urging the second arm  35  to contact the switch  20 . 
     Meanwhile, the second arm  35  is provided with a mass  39  for generating a certain time delay by inertia when the main shaft  10  is rotated in a closing direction. 
     With such construction, when the circuit breaker is opened, as shown in  FIG. 1 , the lever  12  presses the delay plate  30 , and thus the delay plate  30  is spaced apart from the switch  20 . When the main shaft  10  is rotated in a closing direction (i.e., in a counter-clockwise direction in the drawing), the delay plate  30  is pivoted toward the switch  20  in a clockwise direction in the drawing by the urging force of the spring  37 . Here, while the delay plate  30  is pivoted, a certain delay is generated by inertia of the mass  39 . Such delay serves to output a signal from the switch  20  once the delay plate  30  contacts the detection portion of the switch  20  after the fixed contactor and the movable contactor contact each other by the rotation of the main shaft  10 . 
     However, in this conventional time delay output apparatus for a circuit breaker, a relatively large mass  39  is required to generate a certain (fixed) delay, thereby increasing the size of the time delay output apparatus. 
     In addition, when a large current is introduced, the inertia when the mass  39  is vibrated or moved by vibration generated by electromagnetic repulsion force becomes more reduced, compared to that of when the mass  39  is stopped. Accordingly, the delay plate  30  cannot maintain the preset delay. Consequently, the switch  20  outputs a signal too early, and the circuit breaker is instantaneously opened, thereby not performing its function properly. 
     SUMMARY OF THE INVENTION 
     Therefore, it is an object of the present invention to provide a time delay output apparatus for a circuit breaker, which can simplify its construction and reduce its size. 
     It is another object of the present invention to provide a time delay output apparatus for a circuit breaker which can enhance its operational reliability by stably obtaining a time delay. 
     To achieve these and other objects and advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a time delay output apparatus for a circuit breaker, including: a switch disposed at one side of a main shaft rotating in a direction to open/close a fixed contactor and a movable contactor; and a delay member disposed between the main shaft and the switch so as to operate the switch with a preset time delay. 
     Here, there is further provided a reset plate disposed to be separated from the delay member and to interwork with the main shaft so as to generate a time delay, thus to transfer a driving force of the main shaft to the delay member. 
     The reset plate can be configured to rotate centering around a pivot shaft disposed parallel to the main shaft. 
     There is further provided a delay member spring urging the delay member into contact with the switch. 
     The delay member include a pivot shaft, a first contact portion extending from one end of the pivot shaft and contacting the switch, and a second contact portion extending from another end of the pivot shaft. 
     There is further provided a stopper for restricting a pivoting movement of the delay member in a direction to separate the delay member from the switch. 
     The delay member spring may be formed as a coiled tension spring. 
     The delay member spring may have a dead point between the stopper and the switch when the delay member is pivoted. 
     The delay member may function so as to operate the switch after the fixed contactor and the movable contactor contact each other. 
     There is further provided a driving arm disposed protrudingly in a radial direction at the main shaft so as to contact the reset plate. 
     There is further provided a reset plate spring for applying an elastic force urging the reset plate into contact with the driving arm. 
     A bent end portion bent so as to contact the delay member is formed at the reset plate. 
     When the main shaft is rotated to a trip position, the reset plate presses the second contact portion and then the delay member is pivoted, and when the main shaft is rotated in a direction to contact the fixed contactor and the movable contactor with each other, the reset plate presses the first contact portion and thereby the delay member is pivoted. 
     The bent end portion contacts the delay member and restricts the pivoting movement of the delay member when the delay member is suddenly rotated. 
     In the state that the bent end portion and the delay member contact each other, when the main shaft is rotated at the time of closing operation, the bent end portion presses the second contact portion and the reset plate is pivoted in a direction to separate the delay member from the switch, and the reset plate presses the second contact portion such that the second contact portion contacts the switch. 
     According to another aspect of the present invention, there is provided a time delay output apparatus for a circuit breaker, including: a switch disposed at one side of a main shaft rotatable in directions to open/close a fixed contactor and a movable contactor; a delay member disposed between the main shaft and the switch so as to operate the switch with a preset time delay; and a delay member spring for urging the delay member into contact with the switch. 
     According to still another aspect of the present invention, there is provided a time delay output apparatus for a circuit breaker, including: a switch disposed at one side of a main shaft rotatable in directions to open/close a fixed contactor and a movable contactor; a delay member disposed between the main shaft and the switch so as to operate the switch with a preset time delay; a delay member spring for applying an elastic force urging the delay member to contact with the switch; and a reset plate disposed to be separated from the delay member and to interwork with the main shaft so as to generate the time delay, thus to transfer a driving force of the main shaft to the delay member. 
     Here, the reset plate is rotatable centering around a pivot shaft disposed parallel to the main shaft. 
     There is further provided a reset plate spring for applying an elastic force to the reset plate such that the reset plate is urged into contact with the main shaft. 
     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 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
       In the drawings: 
         FIG. 1  is a view illustrating a conventional time delay output apparatus for a circuit breaker; 
         FIG. 2  is a view illustrating a state that the time delay output apparatus for a circuit breaker in  FIG. 1  outputs a signal; 
         FIG. 3  is a side view illustrating a time delay output apparatus for a circuit breaker according to one embodiment of the present invention; 
         FIG. 4  is a top view of the time delay output apparatus for a circuit breaker in  FIG. 3 ; and 
         FIGS. 5 through 7  are views respectively illustrating the operation of the time delay output apparatus for a circuit breaker in  FIG. 3 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Description will now be given in detail of the time delay output apparatus for a circuit breaker according to one embodiment of the present invention, examples of which are illustrated in the accompanying drawings. 
     Referring to  FIGS. 3 and 4 , the time delay output apparatus for a circuit breaker according to the present invention may utilize a signal generating device such as a switch  131  disposed to one side of a main shaft  115  which is rotatable in respective directions to open or close a fixed contactor  111  and a movable contactor  112 ; and a delay member  141  disposed between the main shaft  115  and the switch  131  so as to be pivoted by interworking with a rotation of the main shaft  115 , and for operating the switch  131  with a preset time delay after the fixed contactor  111  and the movable contactor  112  contact each other. 
     A contact switching mechanism  113  for opening/closing the fixed contactor  111  and the movable contactor  112  is connected with the main shaft  115 . And, a driving arm  117  is protrudingly disposed in a radial direction at the main shaft  115 . A reset plate  121  is disposed to one side of the driving arm  117  so as to be pivoted by interworking with the main shaft  115  when the main shaft  115  is pivoted. The reset plate  121  is pivotably coupled to one side of the main shaft  115  centering around a pivot shaft  123  disposed parallel to the main shaft  115 . 
     When an overcurrent relay (not shown) outputs a trip signal, the reset plate  121  may perform a function of returning an actuator (not shown) to its original position, while performing a pivoting movement by interworking with the rotation of the main shaft  115 . Here, the actuator generates a physical trigger signal such that the switching mechanism  113  may perform an opening operation for separating the fixed contactor  111  and the movable contactor  112  from each other. 
     The reset plate  121  is provided with a driving arm contact portion  124  having a curved cross-sectional shape so as to receive one region of the main shaft  115  therein and contacting the driving arm  117  at one end thereof farther away from the pivot shaft  123 . A bent end portion  125  bent so as to contact the delay member  141  is formed to one side of the driving arm contact portion  124 . At one side of the reset plate  121  is connected a reset plate spring  127  for applying an elastic force in a direction such that the driving arm contact portion  124  of the reset plate  121  is urged into contact with the main shaft  115 . 
     Meanwhile, at one side of the main shaft  115  is disposed the switch  131  for outputting a contact signal by interworking with the main shaft  115  when the main shaft  115  is rotated in a closing direction (i.e., in a direction to contact the fixed contactor  111  and the movable contactor  112  with each other). At one side of the switch  131  (i.e., at the upper area as shown in the drawing) is disposed a stopper  133  for stopping the delay member  141  from being pivoted beyond a certain angle in a direction away from the switch  131 . Here, the stopper  133  may be integrally formed at an upper area of a case of the switch  131 . 
     The delay member  141  for being pivoted by interworking with the rotation of the main shaft  115  is disposed at one side of the switch  131  (i.e., at the left side as shown in the drawing). The delay member  141  is provided with a pivot shaft  143  disposed parallel to the main shaft  115 , a first contact portion  145  extending from the pivot shaft  143  to one side and pivotable for contacting the switch  131 , and a second contact portion  147  extending from the pivot shaft  143  to another side and pivoting together with the first contact portion  145 . 
     A delay member spring  151  for applying an elastic force so as to urge the first contact portion  145  of delay member  141  into contact with the switch  131  is connected to one part of the delay member  141  (e.g., the first contact portion  145 ). The delay member spring  151  may be implemented as a coiled tension spring. One end of the delay member spring  151  is connected to the first contact portion  145  so as to form a dead point (dead zone) between the switch  131  and the stopper  133  in a pivot direction of the delay member  141 . This is to exert an elastic urging force from the delay member spring  151 , when the main shaft  115  is at the closing position, the delay member  141  is pivoted in a direction to contact the switch  131 , and when the main shaft  115  is at the opening position, the delay member  141  is pivoted in a direction to be spaced apart from the switch  131 . 
     The second contact portion  147  is provided with a rounded portion  149  implemented as an outer surface of the second contact portion  147  being curved, thereby smoothly contacting the bent end portion  125  of the reset plate  121  when the main shaft  115  is pivoted in the opening direction. Here, the bent end portion  125  is disposed inclined with respect to the delay member  141 . This is to prevent a further pivoting movement of the delay member  125  toward the switch  131  since the bent end portion  125  contacts the rounded portion  149  when the delay member  141  is pivoted by an external force in a direction to approach the switch  131  via the dead point of the delay member spring  151 , and the like. In addition, the bent end portion  125  is disposed inclined with respect to the delay member  141 . When the main shaft  115  is pivoted to a closing position, the bent end portion  125  contacts the rounded portion  149 , and the delay member  141  is pivoted in a direction to separate from the switch  131  so as to pass the dead point of the delay member spring  151 , thereby always uniformly maintaining a preset time delay. 
     With such configuration, when the main shaft  115  is rotated to a closing position, as shown in  FIG. 3 , the first contact portion  145  of the delay member  141  contacts a detection portion  132  of the switch  131  due to an elastic urging force of the delay member spring  151 . Accordingly, the switch  131  outputs a signal based on the contact state. 
     As shown in  FIG. 5 , when the main shaft  115  is rotated to an opening position, the reset plate  121  is pressed by the driving arm  117 , thereby pivoting in a counter-clockwise direction in the drawing. Here, the bent end portion  125  presses the second contact portion  147  of the delay member  141 , and is then pivoted in the direction to separate the first contact portion  145  from the switch  131  (i.e., in a clockwise direction in the drawing). If the delay member spring  151  passes the dead point as the delay member  141  is pivoted, the elastic urging force of the delay member spring  151  serves to pivot the delay member  141  in a clockwise direction. Here, the pivoting movement of the delay member  141  is restricted by the stopper  133 , and thus the first contact portion  145  of the delay member  141  is spaced apart from the switch  131 . 
     If the main shaft  115  is rotated in a closing direction (i.e., in a clockwise direction in the drawing), the reset plate  121  is pivoted in a clockwise direction in the drawing by the elastic urging force of the reset plate spring  127 . Here, since the first contact portion  145  of the delay member  141  is spaced apart from the bent end portion  125  of the reset plate  121  by a certain distance, the bent end portion  125  presses upon the first contact portion  145  after a certain period of time. Accordingly, after the fixed contactor  111  and the movable contactor  112  contact each other, the switch  131  may always output a signal to the outside when the preset time delay has elapsed. 
     Meanwhile, when the delay member  141  is pivoted by an external force, etc. in a direction so as for the first contact portion  145  to approach the switch  131 , as shown in  FIG. 6 , the pivoting movement of the delay member  141  is restricted as the rounded portion  149  contacts the bent end portion  125 . Here, although it may appears in the drawing that the driving arm  117  and the delay member  141  contact each other, they are actually spaced apart from each other along the axial direction of the main shaft  115 , thereby not contacting each other. 
     In the state that the delay member  141  is pivoted via the dead point and contacts the bent end portion  125 , when the main shaft  115  is rotated to a closing position, the reset plate  121  is rotated (in a clockwise direction in the drawing) by the elastic urging force of the reset plate spring  127 . The bent end portion  125  of the reset plate  121  upwardly (in the drawing) presses upon the rounded portion  149  of the second contact portion  147  such that the delay member  141  is pivoted in a direction so as to separate the first contact portion  145  from the switch  131  so as to pass the dead point. The delay member  141  is pivoted in a direction to space the first contact portion  145  apart from the switch  131  by the elastic urging force of the delay member spring  151 , and is then stopped from pivoting further by the stopper  133 , thereby being separated from the switch  131 . 
     As shown in  FIG. 7 , the bent end portion  125  having pivoted past the rounded portion  149  then presses upon the first contact portion  145 , thereby pivoting the delay member  141  toward the switch  131 . When the delay member  141  passes the dead point of the delay member spring  151  while being pivoted, the delay member  141  then continues to pivot under the elastic urging force of the delay member spring  151 . Accordingly, as shown in  FIG. 3 , the first contact portion  145  contacts the detection portion  132  of the switch  131 . The switch  131  outputs a signal to the outside when the first contact portion  145  contacts the detection portion  132 . 
     In the foregoing and shown embodiment, the reset plate operates the delay member, while being pivoted centering around the pivot shaft separate from the main shaft. However, the reset plate may be configured to contact the delay member with a certain time delay, while being pivoted centering around the main shaft. 
     As so far described, the present invention provides a time delay output apparatus for a circuit breaker, which can simplify its construction, reduce its size and lower its manufacturing cost by excluding the use of a large size mass. 
     In addition, the present invention provides a time delay output apparatus for a circuit breaker which can prevent malfunction caused by reduced inertia of when a mass is vibrated or moved by electromagnetic repulsion force or external force, and can enhance operational reliability, by excluding the use of the mass. 
     Further, according to the present invention, even when the delay member is pivoted toward the switch by an external force, etc., the contact end portion of the reset plate and the second contact portion of the delay member may interact with each other. Accordingly, the delay member is always pivoted in a direction to contact the switch at an initial position, and after contacting the contact, the switch may always output a signal after a certain preset time delay, thus to enhance the reliability of its operation. 
     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.