Patent Publication Number: US-8970330-B2

Title: Contactor

Description:
FIELD OF THE INVENTION 
     The present invention relates to the field of switch device, and particularly, to a contactor. 
     BACKGROUND OF THE INVENTION 
     A contactor is a breaking and closing device for frequently closing, carrying and breaking normal current and overloaded current. It is applied on electric power, power distribution and power applications. In electric engineering, since a contactor can quickly disconnect the AC and DC main circuits and connect an apparatus to a large current control circuit, contactors are often used for controlling motors, also used for controlling electrical loads, such as factory equipment, electric heaters, machine tools and a variety of electric power phase units. A contactor not only can close and break a circuit but also has a protective effect on low-voltage release. The contactor has a large control capacity, and is adapted to frequent operation and remote control, therefore it is one of the important components in automatic control systems. When used in different situations, contactors with different rated operational currents are needed. However, the insulating housings of all the phases of a traditional contactor are integral to each other, not absolutely independent from each other, so that it is impossible to improve the rated operational current of the contactor by increasing parallel connections. 
     SUMMARY OF THE INVENTION 
     The object of the present invention is to provide a contactor which has phases absolutely independent from each other and facilitates to increase rated operational current. 
     The present invention provides a contactor including one or more phase units, a mechanical drive controlling the one or more phase units and an electronic control module for driving the mechanical drive, wherein each phase unit comprises an independent insulating housing, and, inside the housing, a positive pole, a static conducting rod connected to the positive pole, a negative pole, a moving conducting rod connected to the negative pole and a counter-force elastic component for driving the moving conducting rod to reset; the mechanical drive comprises a central shaft which passes through the insulating housings of the one or more phase units and drives all the moving conducting rods to electrically contact the static conducting rod, and a transmission which controls the rotation of the central shaft; the electronic control module drives the transmission. 
     Preferably, in one embodiment, the transmission includes a drive rod driving the central shaft to rotate and a magnetic pole core movably connected to the drive rod. The electronic control module includes an inductance coil driving the magnetic pole core to perform straight reciprocating motion. 
     Preferably, in one embodiment, the inductance coil drives the magnetic pole core to perform straight reciprocating motion in horizontal direction. The magnetic pole core drives the drive rod to swing side to side. The drive rod drives the central shaft to rotate either clockwise or anticlockwise within a pre-set angle. 
     Preferably, in one embodiment, the electronic control module also includes a first fixing plate and a second fixing plate which is disposed opposite the first fixing plate. The inductance coil is disposed between the first and second fixing plates, and the magnetic pole core passes through the second fixing plate and is inserted in the inductance coil. 
     Preferably, in one embodiment, a recess is located in an end of the magnetic pole core. A joint which is movable in the recess is provided at one end of the drive rod, and the other end of the drive rod is fastened to the central shaft. 
     Preferably, in one embodiment, the central shaft is provided with a tooth-like portion. The tooth-like portion has a tooth face capable of floating with the rotation of the central shaft. The phase unit also includes a spring chamber provided with a tooth. The tooth-like portion of the central shaft cooperates with the tooth and drives the spring chamber to float. The spring chamber is connected to the moving conducting rod and drives the moving conducting rod to float. 
     Preferably, in one embodiment, the counter-force elastic component is a counter-force spring. One end of the counter-force spring contacts with the insulating housing. The other end of the counter-force spring contacts with a hook portion extending from the spring chamber. The hook portion is able to compress the counter-force spring and reset when the counter-force spring bounces. 
     Preferably, in one embodiment, the contactor includes a plurality of phase units. The central shaft passes through every phase units. The mechanical drive is provided with drive rods and magnetic pole cores respectively corresponding to each of the phase units. The electronic control module is provided with inductance coils respectively corresponding to each of the magnetic pole cores. 
     Preferably, in one embodiment, the contactor also includes a base. The phase units are mounted on the base, and the electronic control module is mounted on the base and located on one side of the phase units. 
     Preferably, in one embodiment, the plurality of phase units form a three-phase contactor, and each phase includes at least two phase units connected in parallel. 
     In the above-mentioned contactor, the electronic control module drives the transmission to move, the transmission drives the central shaft to rotate, the central shaft drives the moving conducting rod and the static conducting rod to be attracted together, and the central shaft passes through the insulating housing(s) of the one or more phase units and is able to drive each of the phase units, such that the contactor can be formed by absolutely independent phase units and convenient to increase the rated operational current thereof by adding phase units along the central shaft. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a perspective view of a contactor according to an embodiment of the present invention. 
         FIG. 2  shows a view of the contactor of  FIG. 1  from another angle. 
         FIG. 3  shows a perspective view of part of a contactor according to an embodiment of the present invention. 
         FIG. 4  shows a perspective view of a phase unit according to an embodiment of the present invention. 
         FIG. 5  shows a section view of the phase unit of  FIG. 4 , inserted with a central shaft and along the line A-A, wherein the static conducting rod contacts with the moving conducting rod. 
         FIG. 6  shows a section view of the phase unit of  FIG. 5 , wherein the static conducting rod is broken from the moving conducting rod. 
         FIG. 7  is a schematic diagram of a contactor according to an embodiment of the present invention, wherein the mechanical drive and the electronic control module is in an initial state of cooperation. 
         FIG. 8  schematically shows a state of being attracted together of  FIG. 7 . 
         FIG. 9  shows a perspective view of a contactor according to another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to  FIGS. 1-5 , the present invention discloses a contactor  100 , including one or more phase units  110 , a mechanical drive  120  controlling the phase unit  110  and an electronic control module  130  driving the mechanical drive  120 . 
     The phase unit  110  includes an independent insulating housing  111 , and, inside the housing, a positive pole  112 , a static conducting rod  113  connected to the positive pole  112 , a negative pole  114 , a moving conducting rod  115  connected to the negative pole  114  and a counter-force elastic component  116  driving the moving conducting rod  115  to reset. 
     The mechanical drive  120  includes a central shaft  121  which passes through the insulating housings  111  of the one or more phase units and drives all the moving conducting rods  115  to electrically contact the static conducting rod  113  at the same time, and a transmission which controls the rotation of the central shaft  121 . The electronic control module  130  drives the transmission. 
     The electronic control module  130  drives the transmission to move, the transmission drives the central shaft  121  to rotate, the central shaft  121  drives the moving conducting rod  115  and the static conducting rod  113  to be attracted together, and the central shaft  121  passes through the insulating housings  111  of the one or more phase units  110  and drives each of the phase units  110 , so as to make the contactor  100  be formed by absolutely independent phase units  110  and convenient to increase the rated operational current by adding phase units  100  along the central shaft  121 . 
     The transmission includes a drive rod  122  for driving the central shaft  121  to rotate and a magnetic pole core  123  movably connected to the drive rod  122 . The electronic control module  130  includes an inductance coil  131  for driving the magnetic pole core  123  to perform straight reciprocating motion. 
     With reference to  FIGS. 1-4 , in the illustrated embodiment of the present invention, the contactor  100  is a three-phase contactor with a rated operational current of up to 400 A. In the embodiment, the inductance coil  131  drives the magnetic pole core  123  to perform straight reciprocating motion in the horizontal direction. The drive rod  122  is driven by the magnetic pole core  123  to swing side to side. The drive rod  122  drives the central shaft  121  to rotate either clockwise or anticlockwise within a pre-set angle. 
     Preferably, the electronic control module  130  further includes a first fixing plate  132  and a second fixing plate  133  which is disposed opposite to the first fixing plate  132 . The magnetic pole core  123  passes through the second fixing plate  133  and is inserted in the inductance coil  131 . 
     Preferably, the electronic control module  130  further includes a first fixing plate  132  and a second fixing plate  133  which is disposed opposite to the first fixing plate  132 . The magnetic pole core  123  passes through the second fixing plate  132  and is inserted in the inductance coil  131 . 
     Preferably, a recess  1231  is provided in one end of the magnetic pole core  123 . A joint  1221  which is movable in the recess  1231  is provided at one end of the drive rod  122 , and the other end of the drive rod  122  is fastened to the central shaft  121 . 
     Preferably, the central shaft  121  is provided with a tooth-like portion  1211 . The tooth-like portion  1211  is provided with a tooth face  1212  which is floated with the rotation of the central shaft  121 . The phase unit  110  also includes a spring chamber  117  provided with a tooth  1171 . The tooth-like portion  1211  of the central shaft  121  cooperates with the tooth  1171  and drives the spring chamber  117  to float. The spring chamber  117  is connected to the drive rod  115  and drives the moving conducting rod  115  to float. Once the moving conducting rod  115  floats upward, it will be attracted to engage with the static conducting rod  113 . 
     The counter-force elastic component  116  is a counter-force spring. One end of the counter-force spring contacts with the insulating housing  111 . The other end of the counter-force spring contacts with a hook portion  1172 , which extends from the spring chamber  117  and is able to compress the counter-force spring and resets when the counter-force spring bounces. 
     The phase unit  110  also includes a conducting wire  118  for connecting the moving conducting rod  115  and the negative pole  114 , and a vacuum conducting chamber  119  for providing a contacting environment for the static conducting rod  113  and the moving conducting rod  115 . 
     When there are multiple phase units  110 , such as three as in the above embodiment, the central shaft  121  passes through all the phase units  110 . The mechanical drive  120  provides a drive rod  122  and a magnetic pole core  123  between every two phase units  110 . The electronic control module  130  is provided with an inductance coil  131  corresponding to each magnetic pole core  123 . So it can ensure all the phase units  110  being driven at the same time, with guaranteeing to have enough power and stability. 
     The contactor  100  also includes a base  140 . The phase units  110  are arranged on the base  140 , and the electronic control module  130  is mounted on the base  140  and placed on a side of the phase units  110 . Because every phase units  110  are absolutely independent to each other, the number of the phase units  110  can be added or reduced simply, and when a certain phase unit  110  needs to be repaired, it can be conveniently repaired or even replaced. 
     Referring to  FIGS. 5-8 , the working principle of the contactor  100  is as follows: In the beginning, the positive pole  112  and the negative pole  114  of each phase unit  110  of the contactor  100  are both in a disconnected state. In the work state, the inductance coil  131  is electrified and then creates a magnetic field which attracts the magnetic pole core  123 , then, the magnetic pole core  123  moves to the inductance coil  131  and drives the drive rod  122  to swing. The swinging of the drive rod  122  drives the central shaft  121  to rotate clockwise (see  FIG. 5 ), and after the rotation of the central shaft  121 , the tooth-like portion  1211  rotates together with the central shaft so as to raise the tooth face  1212  from the initial height to the engagement height, that is, to raise a certain height at the vertical direction, then the tooth-like portion  1211  matches the tooth  1171  of the spring chamber  117 , the tooth face  1212  drives the spring chamber  117  to move upward, so as to drive the moving conducting rod  115  to move upward and finally contact with the static conducting rod  113 , and then, the positive pole  112  will be connected to the negative pole  114 . Because the central shaft  121  passes through every phase units  110  and matches the spring chambers  117  of all the phase units  110 , when the central shaft  121  rotates, every spring chambers  117  can be raised, so as to make the positive poles  112  and the negative poles  114  of all the phase units  110  be connected at the same time. 
     When the inductance coil  131  is power off, the magnetic pole core  123  does not have a magnetic field force, then the magnetic pole core  123  does not have a magnetic force for attracting to make the central shaft  121  drive the drive rod  113 , which causes the force from the tooth face  1212  to the spring chamber  117  to be disappeared, and the counter-force spring, since no force is applied thereto for compressing, begins to bounce, and then causes the spring chamber  117  to fall downward. The falling of the spring chamber  117  in turn acts on the tooth face  1212  to force the central shaft  121  to rotate in a reverse direction, i.e. by anticlockwise, and force the drive rod  122  to swing in a reverse direction to make the magnetic pole core  123  to be drawn out from the inductance coil  131  and return back to its initial state. The falling of the spring chamber  117  brings the moving conducting rod  115  to fall, so as to separate the moving conducting rod  115  and the static conducting rod  113 , and finally make the positive pole  112  and the negative pole  114  to be disconnected. 
     The insulating housings  111  of every phase units  110  are absolutely independent from each other, and can be driven by the central shaft  121  at the same time. In theory, the central shaft  121  can be extended indefinitely, the number of the phase units can be increased indefinitely, and it is convenient to repair and replace any phase unit  110 . Meanwhile, the working current can be increased by paralleling multiple phase units  110 . As shown in  FIG. 9 , the contactor  200  is a three-phase contactor; each phase is composed of two phase units  110  connected in parallel, so that the rated current of the three-phase contactor can be up to 800 A. The rated current of the three-phase contactor can be up to 1200 A by setting each phase as being composed of three phase units  110  connected in parallel. Furthermore, the rated current can be higher by parallel arranged. A contactor with various kinds of rated current can be formed by setting the central shaft  121  and increasing or reducing phase units  110 , so as to solve the problem that the housing of the traditional contactor is a whole and it is difficult to increase the rated current and make repairing or replacing work. 
     Though the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.