Abstract:
A wire connecting apparatus for a magnetic contactor comprises a plurality of wire connector assemblies, a frame for supporting the wire connector assemblies, and a plurality of terminals connected to an external wire. The external wire can be simply connected to the terminal by just tightening or releasing a screw, thereby simplifying an entire wiring process and enhancing a work efficiency.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a wire connecting apparatus for a magnetic contactor, and more particularly, to a screw-type wire connecting apparatus for a magnetic contactor capable of providing an efficient wire connecting work. 
   2. Description of the Conventional Art 
   Generally, a magnetic contactor is a component of an electric power distribution board or a system such as a driving/controlling device of a motor. The magnetic contactor is connected to a wire connected to a system circuit, and opens and closes a circuit on the system. 
   The magnetic contactor has a certain lifespan according to a usage circumstance such as a usage purpose and a switching frequency. Therefore, in an electric power distribution board where a plurality of electronic contactors are installed or in a system such as a driving/controlling device of a motor where a magnetic contactor or a wire connecting of a magnetic contactor has to be changed, connecting a terminal of a magnetic contactor to an external wire connected to of the system circuit is frequently required. 
   The magnetic contactor is provided with a wire connecting apparatus connected to the external wire of the system. The wire connecting apparatus can be sorted into a screw-type apparatus and a lug-type apparatus. 
   Generally, in Asia where an external wire having a ring-shaped compression terminal or a U-shaped compression terminal is applied, a screw-type wire connecting apparatus is mainly used. On the contrary, in Europe and U.S.A, a lug-type wire connecting apparatus is mainly used. 
   In a magnetic contactor having a low rated current less than 25 ampere, a screw-type wire connecting apparatus is applied. In the screw-type wire connecting apparatus, in case of using an ordinary wire or a wire having a U-shaped terminal at a leading end of the wire as an external wire of the system, the external wire can be connected to the wire connecting apparatus just by releasing a screw and then by tightening the screw. 
   However, in the screw-type wire connecting apparatus, in case of using a wire having a ring terminal at a leading end thereof so as to be connected to a terminal of a magnetic contactor, the screw has to be completely separated from the terminal of the magnetic contactor. Then, a screw hole of the magnetic contactor terminal is aligned with a hole of the ring terminal, or a screw is inserted into the ring terminal. Then, the magnetic contactor terminal has to be coupled with the ring terminal by a screw. 
   In order to connect the ring terminal to the screw-type wire connecting apparatus, various tools or two workers are necessary. Accordingly, the number of wiring processes is increased, and a work productivity is lowered. 
   BRIEF DESCRIPTION OF THE INVENTION 
   Therefore, an object of the present invention is to provide a wire connecting apparatus for a magnetic contactor capable of enhancing a productivity and shortening a wiring time by connecting an external wire to a terminal of a magnetic contactor without detaching a screw from the wire connecting apparatus. 
   To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided a wire connecting apparatus for a magnetic contactor, comprising: a plurality of wire connector assemblies; a frame for supporting the wire connector assemblies; and a plurality of terminals connected to an external wire, in which the wire connector assembly comprises: a screw including a head portion, a threaded portion, and a flat surface portion between the head portion and the threaded portion and screw-coupled to the terminal or detached from the terminal, for connecting the external wire to the terminal or detaching the external wire from the terminal; a washer installed at the flat surface portion of the screw for preventing the screw from being detached and widening a contact area between the external wire and the terminal; 
   a screw supporter including an upper plate having a groove portion for supporting the screw, a lower plate, and a connection portion for connecting the upper plate to the lower plate and installed at the frame to be perpendicularly movable, for supporting the screw and the washer to be prevented from vertically detaching therefrom; and 
   a supporter spring having one end supported by the screw supporter and the other end supported by the frame, for providing an elastic force to the screw supporter in an upper direction. 
   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 perspective view showing a magnetic contactor having a wire connecting apparatus according to a first embodiment of the present invention; 
       FIG. 2  is a perspective view showing an upper frame of the magnetic contactor having a wire connecting apparatus according to a first embodiment of the present invention; 
       FIG. 3  is a perspective view showing a screw supporter of the wire connecting apparatus according to the present invention; 
       FIGS. 4 and 5  are perspective views showing a process for completing a wire connector assembly by assembling a supporter spring, a screw, and a washer to the screw supporter of  FIG. 3 ; 
       FIG. 6  is a perspective view showing a state prior to mounting a wire connector assembly and a terminal to the upper frame of the magnetic contactor according to the present invention; and 
       FIG. 7  is a perspective view showing a process for installing and connecting a wire connector assembly, a terminal, and an external wire to the upper frame according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. 
   Hereinafter, a wire connecting apparatus for a magnetic contactor according to the present invention will be explained with reference to the attached drawings. 
     FIG. 1  is a perspective view showing a magnetic contactor  100  having a wire connecting apparatus  200  according to a first embodiment of the present invention. Referring to  FIG. 1 , a lower frame  110  of the magnetic contactor  100  is coupled to an upper frame  210  of a magnetic contactor  200  of  FIG. 2 . A dust cover  101  for preventing dust from being introduced to the upper frame  210  is mounted at the upper frame  210 . In  FIG. 1 , only a washer  330  is shown since the wire connecting apparatus  200  is covered by the dust cover  101 . 
     FIG. 2  is a perspective view showing an upper frame of the magnetic contactor having a wire connecting apparatus according to a first embodiment of the present invention. 
   Referring to  FIG. 2 , the wire connecting apparatus  200  for a magnetic contactor according to the present invention comprises three wire connector assemblies  300 , an upper frame  210  for supporting the wire connector assemblies  300 , and a terminal  350  for connecting a magnetic contactor to an external wire on a circuit. 
   The wire connector assembly  300  comprises a screw  310  for connecting a wire to the terminal  350 , a screw supporter  320  for supporting the screw  310 , a washer  330  installed at the screw  310  for preventing the screw  310  from being detached from the screw supporter  320  and widening a contact area between the external wire and the terminal, and a supporter spring  340  installed at a lower end of the screw supporter  320 . 
   An unexplained reference numeral  220  designates a receiving portion installed on the upper frame  210  for receiving the wire connector assembly  300 . Also, an unexplained reference numeral  225  designates a guide slit installed on the upper frame  210  for guiding the screw supporter to be moved in a perpendicular direction. 
     FIG. 3  is a perspective view showing the screw supporter of the wire connecting apparatus according to the present invention. The screw supporter  320  will be explained in more detail with reference to  FIG. 3 . 
   The screw supporter  320  comprises an upper plate  322  having a groove portion  321  for supporting the screw  310 , a lower plate  323 , and a connection portion  324  for connecting the upper plate  322  to the lower plate  323 . 
   The groove portion  321  of the upper plate  322  is provided with a pair of inclined surfaces  321   a  having a decreasing width towards an inner side thereof for guiding the inserting of the screw  310  at an entrance thereof. A supporting portion  321   b  for mounting the inserted screw  310  is extending from the inclined surface  321   a  at an inner side of the groove portion  321 . A pair of neck portions  321   c  for preventing the screw  310  inserted into the supporting portion  321   b  from being detached from the supporting portion  321   b  are provided between the inclined surface  321   a  and the supporting portion  321   b.    
   A head portion  310   a  of the screw  310  is mounted at an upper surface of the upper plate  322 . A flat surface portion  310   c  where the threaded portion  310   b  is not formed is inserted into the supporting portion  321   b . The supporting portion  321   b  has a partial circular shape having a diameter equal or a little larger to/than a diameter of the flat surface portion  310   c  of the screw  310 . A gap between the two neck portions  321   c  is equal or smaller to/than the diameter of the flat surface portion  310   c.    
   The connection portion  324  is provided with a rectangular through hole  324   a  for passing the terminal  350  at the center thereof. The connection portion  324  is integrally formed at each edge of the upper plate  322  and the lower plate  323  in a perpendicular direction to the upper plate  322  and the lower plate  323 . The connection portion  324  has a rectangular shape having a vertical edge longer than a horizontal edge, a window frame shape. 
   The connection portion  324  comprises a pair of vertical frames  324   b  parallel with each other, and a horizontal frame  324   c  for connecting both ends of the vertical frames  324   b.    
   The vertical frame  324   b  connects the upper plate  322  to the lower plate  323 , and couples the wire connector assembly  300  to the receiving portion  220  provided at the upper frame  210  of the wire connecting apparatus  200 . 
   Therefore, a width between the two vertical frames  324   b , that is, a length of the horizontal frame  324   c  is longer than a width of the upper plate  322  and the lower plate  323  to be coupled to the upper frame  210 . 
   A supporting boss  325  for supporting an upper end of the supporter spring  340  is integrally formed at a lower surface of the lower plate  323  downwardly. Two spring supporting protrusions  325   a  protruding from an outer circumferential surface of the supporting boss  325  for preventing the supporter spring  340  from being detached therefrom are provided. 
   Referring to  FIGS. 4 and 5 , will be explained a construction of the screw  310 , a process for installing and supporting the screw  310  and the washer  330  to the screw supporter  320 , and a process for installing the supporter spring  340  to the supporting boss  325  of the lower plate  323 . 
   The screw  310  comprises the head portion  310   a  and the body portion. 
   The head portion  310   a  is provided with a groove portion for inserting a tool such as a driver at an upper surface thereof, and has a diameter larger than a diameter of the body portion. The body portion is integrally extending from a lower surface of the head portion  310   a  in a perpendicular direction. The body portion includes a threaded portion  310   b  having a threaded surface at an outer circumferential surface thereof, and a flat surface portion  310   c  formed between the head portion  310   a  and the threaded portion  310   b.    
   The screw  310  is installed at the screw supporter  320 , and is coupled to the terminal  350  of the wire connecting apparatus  200 . The washer  330  is installed at the flat surface portion  310   c  of the screw  310  in order to prevent the screw  310  from being detached from the screw supporter  320  in a vertical direction and in order to minimize an electrical resistance by widening a contact area between the terminal  350  and the external wire  400  of  FIG. 7 . 
   A length of the flat surface portion  310   c  is longer than a sum between a thickness of the washer  330  and a thickness of the upper plate  322  of the screw supporter  320  due to the following reason. As shown in  FIG. 4 , when the screw  310  and the washer  330  are installed at the screw supporter  320 , the upper plate  322  of the screw supporter  320  is inserted between the washer  330  and the head portion  310   a  at the entire length of the flat surface portion  310   c  except the thickness of the washer  330 . 
   A process for installing the screw  310  and the washer  330  at the screw supporter  320  will be explained. 
   Under a state that the screw  310  and the washer  330  are coupled to each other, the flat surface portion  310   c  below the head portion  310   a  of the screw  310  is positioned in the groove portion  321  formed at the upper plate  322  of the screw supporter  320 . Then, the screw  310  is inserted into the neck portion  321   c  having a diameter shorter than a diameter of the flat surface portion  310   c  along the inclined surface  321   a  of the groove portion  321 , so that the groove portion  321  is widened right and left. As the flat surface portion  310   c  of the screw  310  passes through the neck portion  321   c  of the groove portion  321 , the head portion  310   a  of the screw  310  is mounted at the supporting portion  321   b . The groove portion  320  widened right and left to some degree is restored to the original state, and the neck portion  321   c  prevents the screw  310  from being detached from the supporting portion  321   b  in a horizontal direction. 
   A process for coupling the supporter spring  340  to the screw supporter  320  will be explained. The supporting boss  325  of the lower plate  323  is positioned at an upper end of the supporter spring  340  and then is forcibly inserted into the screw supporter  320 . As the result, the upper end of the supporter spring  340  is simply coupled to the spring supporting protrusion  325   a . The supporter spring  340  coupled to the spring supporting protrusion  325   a  is not detached from the supporting boss  325 . 
     FIG. 6  is a perspective view showing a state prior to mounting a wire connector assembly at the upper frame of The magnetic contactor according to the present invention. Referring to  FIG. 6 , the upper frame  210  and the receiving portion  220  will be explained in more detail. 
   The upper frame  210  of the wire connecting apparatus  200  according to the present invention comprises a body portion  230 , and an insulating partition wall  240  protruding from the body  230  in a longitudinal direction and having a predetermined gap from the body in a width direction. 
   The insulating partition walls  240  are symmetrically disposed at both sides of the body portion  230 , and the receiving portion  220  for receiving the wire connector assembly  300  is disposed between the insulating partition walls  240 . That is, the insulating partition wall  240  insulates each of the wire connector assembly  300  installed at the receiving portion  220 . 
   To the wire connector assembly  300  inside one receiving portion  220  of the body  230 , an external wire for a power source is connected. Also, to the wire connector assembly  300  inside another receiving portion  220  of the body  230 , an external wire for electrical load is connected. 
   The guide slit  225  coupled to the vertical frame  324   b  of the screw supporter  320  is formed at the receiving portion  220 . The guide slit  225  is vertically provided at rear portions of both inner side surfaces of the receiving portion  220 , that is, at a contact edge between one surface of the body portion  230  of the upper frame  210  and the insulating partition wall  240 . A pair of the guide slits  225  are provided at each phase of an electrical current. Referring to  FIG. 6 , three pairs of guide slits  225  are provided at magnetic contactor for alternating current of three phases. The vertical frame  324   b  is slidably inserted into the guide slit  225 , and is moved in a longitudinal direction of the guide slit  225 . 
   A lift-limiting stopper  227  for limiting a lifting of the screw supporter  320  is protruding from one surface of the body  230  of the upper frame  210 , that is, a rear surface of the receiving portion  220 . Each of the lift-limiting stopper  227  is provided at six receiving portions  220 . An unexplained reference numeral  227   a  designates an inclined surface of the lift-limiting stopper  227 . The inclined surface  227   a  is protruding downwardly, and guides the screw supporter  320  to be downwardly moved. However, the inclined surface  227   a  does not allow the screw supporter  320  that has slid onto the inclined surface  227   a  to be upwardly moved. 
   A terminal insertion hole  229  for inserting a rear end of the terminal  350  is provided just below the lift-limiting stopper  227 . A terminal insertion groove portion  235  for guiding the terminal  350  to be slid-inserted thereinto and supporting the terminal  350  is provided at an inner wall of the receiving portion, that is, an inner wall of the insulating partition wall at the same height as the terminal insertion hole  229 . 
   A pair of spring supporting walls  226  facing each other and protruding from the insulating partition wall  240  for supporting the supporter spring  240  are formed at a lower portion of each receiving portion  220 , that is, just below the terminal insertion groove portion  235 . 
   A spring seat portion  238  downwardly concaved for supporting a lower end of the supporter spring  340  is provided at a bottom surface of the receiving portion  220 . 
   Referring to  FIG. 7 , a process for installing the wire connector assembly  300  and the terminal  350  at the receiving portion  220  of the upper frame  210  and connecting the external wire  400  to the terminal  350  by the wire connector assembly  300  will be explained. 
   The wire connector assembly  300  is installed at the receiving portion  220  as follows. 
   The screw  310 , the washer  330 , and the supporter spring  340  are assembled to the screw supporter  320 , thereby providing the wire connector assembly  300 . The vertical frame  324   b  of the connection portion  324  of the screw supporter  320  is inserted into the guide slit  225  of the receiving portion  220 . Then, an upper portion of the wire connector assembly  300 , that is, the head portion  310   a  of the screw  310  is downwardly pressed. Desirably, an opening of the groove portion  321  of the upper plate  322  is positioned towards the insulating partition wall  240  so as to prevent the screw  310  from being horizontally detached from the screw supporter  320 . 
   The terminal  350  is slid along the guide slit  225  thus to be downwardly moved. When the terminal  350  comes in contact with the inclined surface  227   a  of the lift-limiting stopper  227 , the terminal  350  is temporarily stopped. 
   When the head portion  310   a  of the screw  310  is pressed more strongly, the horizontal frame  324   c  climbs over the inclined surface  227   a , so that the wire connector assembly  30  is moved more downwardly. 
   When a lower end of the supporter spring  340  comes in contact with the spring seat portion  238 , the pressurization onto the terminal  350  is stopped. As the result, the wire connector assembly  300  is lifted by an elastic force of the supporter spring  340 . However, since an upper surface of the horizontal frame  324   c  is stopped by the lift-limiting stopper  227 , the wire connector assembly  300  is stopped thereby to be positioned in the receiving portion  220 . 
   The process for installing the terminal  350  at the upper frame  210  and electrically and mechanically connecting the external wire  400  to the terminal  350  by using the screw  310  will be explained. 
   First, a rear end of the terminal  350  is inserted into the insertion groove portion  235  via the through hole  324   a  of the screw supporter  320  with pressing the head portion  310   a  of the screw  310  so that the insertion hole  229  can be exposed, thereby completing the installation of the terminal  350 . 
   Then, the external wire  400  having a ring terminal at a leading end thereof is positioned at an upper surface of the terminal  350 . The screw supporter  320  receives an elastic bias force in a vertical upper direction by the supporter spring  340 . However, the screw supporter  320  is prevented from being lifted due to the terminal  350  fixed by the insertion hole  229  and the insertion groove portion  235 . 
   Under the state, when the screw  310  is clockwise rotated while pressing the wire connector assembly  300  downwardly by using a tool such as a driver, etc., the threaded portion  310   b  of the screw  310  passes through the ring terminal hole of the external wire  400  and a screw insertion hole  350   a  of the terminal  350 . Accordingly, the washer  320  comes in contact with the terminal  350 . As the washer  320  having an area larger than an area of the ring terminal presses the terminal  350 , a leading end  400   a  of the external wire  400 , that is, the ring terminal comes in contact with the terminal  350  thereby to minimize an electrical resistance. A thread is formed at an inner circumferential surface of the screw insertion hole  350   a  of the terminal  350 . The screw  310  is coupled to the screw insertion hole  350   a  of the terminal  350 . Accordingly, connecting the external wire  400  to the wire, connecting apparatus  200  for a magnetic contactor  100  according to the present invention is completed. 
   When the tightened screw  310  is detached from the screw insertion hole  350   a  of the terminal  350  by being counterclockwise rotated, the screw supporter  32  is automatically lifted by an elastic force of the supporter spring  340 . Accordingly, the screw  310  is upwardly spaced from the terminal  350  with a predetermined distance. Since the upper surface of the horizontal frame  324   c  of the screw supporter  320  is stopped by the fixed terminal  350 , a lifting of the wire connector assembly  300  is limited. Therefore, the wire connector assembly  300  is not detached from the receiving portion  220 . 
   As aforementioned, in the present invention, the screw has only to be tightened or released at the time of connecting or detaching the wire on the circuit to/from the terminal of the wire connecting apparatus, and the wire connector assembly is not detached from the magnetic contactor. Accordingly, an operation process is simplified. 
   Furthermore, one worker can perform a wiring without other person&#39;s help thereby to enhance a work productivity. 
   As the present invention may be embodied in several forms without departing from the spirit or essential 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 spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalence of such metes and bounds are therefore intended to be embraced by the appended claims.