Patent Publication Number: US-2020303146-A1

Title: Contact structure and switch apparatus

Description:
PRIORITY STATEMENT 
     This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/EP2017/057287 which has an International filing date of Mar. 28, 2017, which designated the United States of America, and which claims priority under 35 U.S.C. § 119 to Chinese patent application No. 201610188243.1 filed Mar. 29, 2016, the entire contents of which are hereby incorporated herein by reference. 
    
    
     FIELD 
     Embodiments of the present invention generally relates to the technical field of electronics and electricity, in particular to a contact structure and switch apparatus. 
     BACKGROUND 
     A switch apparatus is an electrical device that is indispensable in an electric circuit. As a special class of switch apparatus, contactors and relays are widely used in many fields, such as electricity transmission, distribution and consumption. When a large-current circuit needs to use a contactor or a relay, a corresponding large-current contactor or large-current relay must be selected, to ensure that the contactor or relay can operate normally under a large current, and is not damaged by heat caused by a large current. 
     At present, to ensure that the contactor or relay can withstand a large current, the large-current contactor or large-current relay generally has a bridge contact structure comprising a thick conduction bridge. Two ends of the conduction bridge are each provided with at least one moving contact, which is moved by movement of the conduction bridge, to bring into contact or separate the moving contact and a corresponding static contact. 
     With regard to the prior art, the bridge contact structure at least comprises two moving contacts and two static contacts. 
     The contacts are generally made of a silver alloy material, but silver is a precious metal, with a high price. Since the number of contacts is large, a large amount of silver alloy must be consumed, and as a result, a switch apparatus with such a bridge contact structure has a high cost. 
     SUMMARY 
     The present invention proposes a contact structure and a switch apparatus, which can reduce the number of contacts in a contact structure. 
     An embodiment of the present invention provides a contact structure, comprising: 
     a first contact, a second contact, a first contact arm and a second contact arm; 
     the first contact arm comprises at least two spring plates, which are arranged one on top of another and fixed to each other at one end; 
     the second contact is located on the second contact arm; 
     the first contact is located on the spring plate on that side of the first contact arm which is closer to the second contact arm; and 
     at least two spring plates included in the first contact arm, under a driving action, experience elastic deformation which causes the first contact and the second contact to come into contact with each other. 
     In one embodiment of the present invention, 
     the second contact arm is a conductor which has no elastic deformation capability; and 
     one end of the second contact arm is fixed in place, and the second contact is fixed to the other end of the second contact arm. 
     In another embodiment of the present invention, 
     the second contact arm comprises at least two spring plates, which are arranged one on top of another and fixed to each other at one end; 
     the second contact is located on the spring plate on that side of the second contact arm which is closer to the first contact arm; and 
     at least two spring plates included in the second contact arm, under a driving action, experience elastic deformation which causes the first contact and the second contact to come into contact with each other. 
     In one embodiment of the present invention, the length difference and width difference of any two of the spring plates arranged one on top of another are both smaller than a preset standard error value. 
     In one embodiment of the present invention, a groove is provided on that face of any one of the spring plates which is in contact with another spring plate. 
     In one embodiment of the present invention, the thickness of each of the spring plates is less than or equal to a predetermined critical thickness, so that the travel of the elastic deformation of each of the spring plates is greater than or equal to the contact travel between the first contact and the second contact. 
     In one embodiment of the present invention, 
     the second contact arm comprises at least two spring plates, which are arranged in parallel and connected together in sequence, with any two connected spring plates forming a “ ” shaped structure; 
     the second contact is located on the spring plate on that side of the second contact arm which is closer to the first contact arm; and 
     at least two spring plates included in the second contact arm, under a driving action, experience elastic deformation which causes the first contact and the second contact to come into contact with each other. 
     Any two of the spring plates which are connected together are fixed by welding or riveting, or any two connected spring plates are formed by folding and bending an elongated piece of elastic material. 
     In one embodiment of the present invention, the material of the spring plate comprises: a copper alloy. 
     In one embodiment of the present invention, the material of the second contact arm comprises: a copper alloy. 
     An embodiment of the present invention also provides a switch apparatus, comprising: 
     at least one driver and any contact structure provided in an embodiment of the present invention; and 
     the driver is used for driving at least two spring plates included in the first contact arm in the contact structure. 
     In one embodiment of the present invention, when the second contact arm in the contact structure has elastic deformation capability, the driver is further used for driving the second contact arm. 
     An embodiment of the present invention provides a contact structure and a switch apparatus; the first contact arm comprises at least two spring plates, the first contact is disposed on the spring plate on the side closer to the second contact arm, and at least two spring plates included in the first contact arm experience elastic deformation under a driving action, causing the first contact to move, and realizing contact between the first contact and second contact. 
     Since the first contact arm comprises at least two spring plates fixed to each other at one end, the elastic deformation capability of the first contact arm is increased; the spring plates are disposed one on top of another, to ensure that the cross-sectional area of the first contact arm meets the requirements of a large current. Thus, the elastic deformation capability of the first contact arm is increased while ensuring that the cross-sectional area of the first contact arm meets the requirements of a large current. Hence, in large-current applications, the first contact can be brought into contact with the second contact through elastic deformation of the first contact arm. This contact structure only has one pair of contacts, so the number of contacts is reduced. 
    
    
     
       BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       To explain the technical solution in embodiments of the present invention or in the prior art more clearly, there follows a simple description of the accompanying drawings that need to be used in description of embodiments or the prior art. Obviously, the drawings in the description below are some embodiments of the present invention, and a person skilled in the art could obtain other drawings based on these drawings without expending any inventive effort. 
         FIG. 1  is a schematic diagram of a contact structure provided in one embodiment of the present invention; 
         FIG. 2  is a schematic diagram of a contact structure provided in another embodiment of the present invention; 
         FIG. 3  is a schematic diagram of a contact structure provided in another embodiment of the present invention; 
         FIG. 4  is a schematic diagram of a contact structure provided in another embodiment of the present invention; 
         FIG. 5  is a schematic diagram of a switch apparatus provided in one embodiment of the present invention; 
         FIG. 6  is a schematic diagram of a switch apparatus provided in another embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     To clarify the object, technical solution and advantages of embodiments of the present invention, the technical solution in embodiments of the present invention is described clearly and completely in conjunction with the drawings in embodiments of the present invention. Obviously, the embodiments described are some, not all, of the embodiments of the present invention. Based on embodiments in the present invention, all other embodiments obtained by those skilled in the art without expending any inventive effort shall be included in the scope of protection of the present invention. 
     One embodiment of the present invention provides a contact structure, comprising: a first contact, a second contact, a first contact arm and a second contact arm; the first contact arm comprises at least two spring plates, which are arranged one on top of another and fixed to each other at one end; the second contact is located on the second contact arm; the first contact is located on the spring plate on that side of the first contact arm which is closer to the second contact arm; at least two spring plates included in the first contact arm, under a driving action, experience elastic deformation which causes the first contact and the second contact to come into contact with each other. 
     According to the invention embodiment described above, the first contact arm comprises at least two spring plates, the first contact is disposed on the spring plate on the side closer to the second contact arm, and at least two spring plates included in the first contact arm, under a driving action, experience elastic deformation, causing the first contact to move, and realizing contact between the first contact and second contact. Since the first contact arm comprises at least two spring plates fixed to each other at one end, the elastic deformation capability of the first contact arm is increased; the spring plates are disposed one on top of another, to ensure that the cross-sectional area of the first contact arm meets the requirements of a large current. Thus, the elastic deformation capability of the first contact arm is increased while ensuring that the cross-sectional area of the first contact arm meets the requirements of a large current. Hence, in large-current applications, the first contact can be brought into contact with the second contact through elastic deformation of the first contact arm. This contact structure only has one pair of contacts, so the number of contacts is reduced. 
     In one embodiment of the present invention, the form of the second contact arm is not defined. The second contact arm may have no elastic deformation capability, and be in a stationary state during the process of establishing contact between or separating the first contact and the second contact. Alternatively, the second contact arm may have elastic deformation capability, and experience elastic deformation under a driving action during the process of establishing contact between or separating the first contact and the second contact. Depending on whether the second contact arm has elastic deformation capability, the contact structure provided in an embodiment of the present invention can be realized in the following two manners: 
     manner A: the second contact arm has no elastic deformation capability; and 
     manner B: the second contact arm has elastic deformation capability. 
     The realizations of the contact structures in manner A and manner B are explained separately below. 
     With Regard to Manner A 
     In manner A, the case where the first contact arm comprises two spring plates is taken as an example; see  FIG. 1  for this contact structure. As shown in  FIG. 1 , the contact structure comprises: a first contact arm  101 , a second contact arm  102 , a first contact  103  and a second contact  104 , wherein 
     the first contact arm  101  comprises: a spring plate  1011  and a spring plate  1012 , which are arranged one on top of another, with one end of the spring plate  1011  and one end of the spring plate  1012  both being fixed to a support  108  via a screw  105 ; 
     the first contact  103  is fixed to that side of the spring plate  1011  which is closer to the second contact arm  102 ; 
     the second contact arm  102  is fixed to a support  108  via a screw  106 ; and 
     the second contact  104  is fixed to that side of the second contact arm  102  which is closer to the first contact arm  101 . 
     In an embodiment of the present invention, the first contact arm  101  is composed of the spring plate  1011  and the spring plate  1012 . The spring plate  1011  and the spring plate  1012  experience bending deformation under a driving action, causing the first contact  103  to move towards the second contact  104 . The second contact arm  102  is in a stationary state, until the first contact  103  comes into contact with the second contact  104 . By designing the first contact arm  101  to take the form of two spring plates, the elastic deformation capability of the first contact arm  101  is increased while keeping the current-carrying ability of the first contact arm  101  unchanged, so as to have the ability to establish contact between the first contact  103  and second contact  104  through elastic deformation. Thus, a contact structure used in the field of large-currents can have just one pair of contacts, so the number of contacts is reduced relative to the prior art. 
     There follows a more detailed explanation of the principle whereby the elastic deformation capability of the first contact arm  101  can be increased while keeping the current-carrying ability unchanged. 
     Formula one below shows that the resistance of a material is directly proportional to the length of the material, and inversely proportional to the cross-sectional area of the material; the cross-sectional area of a material is directly proportional to the width and thickness of the material. To guarantee the current-carrying ability of a material, the resistance of the material must be kept at a low level, so the cross-sectional area of the material must attain a certain value if the length of the material remains unchanged. 
     Formula one is as follows: 
     
       
         
           
             R 
             = 
             
               
                 ρ 
                 · 
                 
                   L 
                   S 
                 
               
               = 
               
                 L 
                 
                   T 
                   · 
                   B 
                 
               
             
           
         
       
     
     where R is the resistance of the material, ρ is the resistivity of the material, L is the length of the material, S is the cross-sectional area of the material, T is the thickness of the material, and B is the width of the material. 
     Formula two below shows that the amount of deformation of a material is directly proportional to the driving force to which the material is subjected and the cube of the material length, and inversely proportional to the elastic modulus and sectional inertia of the material; the sectional inertia of the material is directly proportional to the width and the cube of the thickness of the material. To increase the elastic deformation capability, the thickness of the material must be made less than a given value if the length and width of the material are kept unchanged. 
     Formula two is as follows: 
     
       
         
           
             Y 
             = 
             
               
                 
                   F 
                   · 
                   
                     L 
                     3 
                   
                 
                 
                   3 
                    
                   
                     E 
                     · 
                     I 
                   
                 
               
               = 
               
                 
                   4 
                    
                   
                     F 
                     · 
                     
                       L 
                       3 
                     
                   
                 
                 
                   E 
                   · 
                   B 
                   · 
                   
                     T 
                     3 
                   
                 
               
             
           
         
       
     
     where Y is the amount of deformation of the material, F is the driving force to which the material is subjected, L is the length of the material, E is the elastic modulus of the material, I is the sectional inertia of the material, B is the width of the material, and T is the thickness of the material. 
     Comparing the dual-spring-plate first contact arm  101  with the conduction arm in a bridge contact structure, according to formula one, since the spring plate  1011  and spring plate  1012  are in tight contact after being laid one on top of another, the sum of the cross-sectional areas of the spring plate  1011  and spring plate  1012  is equal to the cross-sectional area of the conduction bridge. Thus, the cross-sectional area of the first contact arm  101  has not changed, so the resistance of the first contact arm  101  has not changed either, thereby ensuring that the current-carrying ability of the first contact arm  101  does not change. 
     According to formula two, since the sum of the thicknesses of the spring plate  1011  and spring plate  1012  is equal to the thickness of the conduction bridge, and the amount of deformation of the spring plate is inversely proportional to the cube of the thickness of the spring plate, if the thickness of the spring plate  1011  and the thickness of the spring plate  1012  are each equal to one half of the thickness of the conduction bridge, the driving force needed to cause the spring plate  1011  or spring plate  1012  to experience an amount of deformation the same as that of the conduction bridge is only one eighth of that in the case of the conduction bridge, and the sum of the driving forces needed by the spring plate  1011  and spring plate  1012  is one quarter of that in the case of the conduction bridge, so the elastic deformation capability of the first contact arm  101  is increased. In summary, by cutting the first contact arm  101  into the spring plate  1011  and spring plate  1012 , the elastic deformation capability of the first contact arm  101  is increased, while ensuring that the current-carrying ability remains unchanged. 
     In an embodiment of the present invention, to ensure that the first contact  103  can come into contact with the second contact  104 , and the spring plates do not exceed elastic limits during deformation, each spring plate must have sufficient elastic deformation capability. According to formula two, the smaller the thickness of the spring plate, the smaller the tension arising through deformation. Based on the size of current borne by the contact structure, an initial distance between the two contacts when the contact arms are not driven is determined. A critical thickness of each spring plate is determined according to the initial distance between the two contacts. The thickness of each spring plate cannot exceed the critical thickness, but no restriction is imposed in terms of whether the thicknesses of the spring plates are equal. 
     It must be explained that the embodiment shown in  FIG. 1  is just one feasible embodiment of the present invention. The first contact arm may comprise a greater number of spring plates according to actual service requirements, to further increase the elastic deformation capability of the first contact arm. 
     In an embodiment of the present invention, as shown in  FIG. 1 , a wiring board  107  is further disposed between the first contact arm  101  and support  108 . The wiring board  107  is in contact with the first contact arm  101 , and used for connecting to an external input electrode. The second contact arm  102  is connected to a corresponding output electrode. Under the action of a driving force, the spring plate  1011  and spring plate  1012  bend towards the second contact arm  102 . When the first contact  103  and second contact  104  have come into contact with each other, the spring plate  1011  and spring plate  1012  are in tight contact with each other, connecting the input electrode to the output electrode. 
     With Regard to Manner B 
     In manner B, the second contact arm has elastic deformation capability. The second contact arm may have the same structure as the first contact arm, or another form of structure. The contact structure in manner B can be divided into the following two forms, according to the form of the second contact arm: 
     first form: the second contact arm comprises at least two spring plates, the specific structure being the same as that of the first contact arm; and 
     second form: the second contact arm comprises at least two spring plates, which are arranged in parallel and connected together in sequence, with any two connected spring plates forming a “ ” shaped structure. 
     The two forms in manner B are explained separately below. 
     With Regard to the First Form in Manner B 
     The case of the first contact arm and the second contact arm each comprising two spring plates is taken as an example; see  FIG. 2  for this contact structure. As shown in  FIG. 2 , the contact structure comprises: a first contact arm  201 , a second contact arm  202 , a first contact  203  and a second contact  204 , wherein the first contact arm  201  comprises: a spring plate  2011  and a spring plate  2012 , which are arranged one on top of another, with one end of the spring plate  2011  and one end of the spring plate  2012  both being fixed to a support  208  via a screw  205 ; the first contact  203  is fixed to that side of the spring plate  2011  which is closer to the second contact arm  202 ; the second contact arm  202  comprises: a spring plate  2021  and a spring plate  2022 , which are arranged one on top of another, with one end of the spring plate  2021  and one end of the spring plate  2022  both being fixed to a support  208  via a screw  206 ; the second contact  204  is fixed to that side of the spring plate  2021  which is closer to the first contact arm  201 ; 
     The spring plate  2011  and spring plate  2012  experience bending deformation towards the second contact arm  202  under a driving action, causing the first contact  203  to move towards the second contact arm  202 , and the spring plate  2021  and spring plate  2022  experience bending deformation towards the first contact arm  201  under a driving action, causing the second contact  204  to move towards the first contact arm  201 , until the first contact  203  and second contact  204  come into contact with each other. The first contact arm  201  and second contact arm  202  both have a dual-spring-plate structure, so the elastic deformation capability of the first contact arm  201  and second contact arm  202  are increased while keeping the current-carrying ability of the first contact arm  201  and second contact arm  202  unchanged. Thus, the two contacts can be caused to come into contact or separated by causing elastic deformation of the two contact arms. Compared with the bridge structure in the prior art, this contact structure needs just one pair of contacts, so the number of contacts is reduced. 
     In an embodiment of the present invention, as  FIG. 2  shows, a first wiring board  207  is further disposed between the first contact arm  201  and support  208 , with the first wiring board  207  being in contact with the first contact arm  201 ; a second wiring board  209  is further disposed between the second contact arm  202  and support  208 , the second wiring board  209  being in contact with the second contact arm  202 . The first wiring board  207  and second wiring board  209  are used for connecting an external input electrode and an output electrode respectively. A good contact can be ensured between the contact arm and the electrode via the wiring board, preventing a bad contact from occurring between the contact arm and the electrode during deformation of the contact arm. 
     In an embodiment of the present invention, the first contact arm  201  and the second contact arm  202  can both experience elastic deformation, causing the first contact  203  and the second contact  204  to move. Since the two contact arms can both experience elastic deformation, compared to the contact structure in manner A, the cross-sectional area of the two contact arms and the initial distance between the two contacts when the contact arm is not being driven can be increased, thereby enabling the contact structure to withstand a larger current. 
     With Regard to the Second Form of Manner B 
     The case where the first contact arm comprises two spring plates and the second contact arm comprises three spring plates is taken as an example; see  FIG. 3  for this contact structure. 
     As shown in  FIG. 3 , the contact structure comprises: a first contact arm  301 , a second contact arm  302 , a first contact  303  and a second contact  304 , wherein the first contact arm  301  comprises: a spring plate  3011  and a spring plate  3012 , which are arranged one on top of another, with one end of the spring plate  3011  and one end of the spring plate  3012  both being fixed to a support  308  via a screw  305 ; the first contact  303  is fixed to that side of the spring plate  3011  which is closer to the second contact arm  302 ; the second contact arm  302  comprises: a spring plate  3021 , a spring plate  3022  and a spring plate  3023 ; the spring plate  3021 , spring plate  3022  and spring plate  3023  are arranged in parallel and connected together in sequence; the spring plate  3021  and spring plate  3022  forma “ ” shaped structure, the spring plate  3022  and spring plate  3023  form a “ ” shaped structure, and one end of the spring plate  3023  is fixed to the support  308  via a screw  306 ; the second contact  304  is fixed to that side of the spring plate  3021  which is closer to the first contact arm  301 . 
     The spring plate  3011  and spring plate  3012  experience bending deformation towards the second contact arm  302  under the action of a driving force, causing the first contact  303  to move towards the second contact arm  302 ; the spring plate  3021 , spring plate  3022  and spring plate  3023  each experience bending deformation under the action of a driving force; the included angle between the spring plate  3021  and spring plate  3022  and the included angle between the spring plate  3022  and spring plate  3023  both increase; the entire second contact arm  302  extends towards the first contact arm  301 , causing the second contact  304  to move towards the first contact arm  301 , until the first contact  303  and the second contact  304  come into contact with each other. The elastic deformation capability of the first contact arm  301  is increased while ensuring current-carrying ability via the dual-spring-plate structure, and the second contact arm  302  adds together the elastic deformations of multiple spring plates, increasing the elastic deformation capability of the second contact arm  302 , so that the two contacts are caused to come into contact with each other through the elastic deformation of the first contact arm  301  and second contact arm  302 . Thus the contact structure only has one pair of contacts, so the number of contacts is reduced relative to the bridge structure in the prior art. 
     In an embodiment of the present invention, the three spring plates included in the second contact arm  302  are arranged in parallel and connected to each other in sequence, so that two adjacent spring plates form a “ ” shaped structure. The entire second contact arm  302  forms a structure of a spring; under the action of a driving force, each spring plate experiences a certain amount of elastic deformation, with the amount of deformation of the second contact arm  302  being equal to the sum of the amounts of deformation of the spring plates. Thus, spring plates with poor elastic deformation capability are combined, increasing the elastic deformation capability of the second contact arm  302 , and ensuring that the total travel of the first contact arm  301  and second contact arm  302  can cause the two contacts to come into contact with each other. 
     In an embodiment of the present invention, in the second contact arm  302 , two connected spring plates can be fixed by riveting or welding, or a longer elastic material may be bent and folded to form two spring plates, thereby reducing the process step of fixing together two connected spring plates, and reducing the cost of the contact structure. 
     In one embodiment of the present invention, to ensure that spring plates disposed one on top of another can be in good contact, a groove may be provided on that face of any spring plate which is in contact with another spring plate. In this way the contact performance between spring plates arranged one on top of another can be improved. The case of the contact structure shown in  FIG. 1  is taken as an example below, and the realization of a spring plate provided with a groove is explained further. 
     As  FIG. 4  shows, one embodiment of the present invention provides a contact structure, comprising: a first contact arm  401 , a second contact arm  402 , a first contact  403  and a second contact  404 , wherein the first contact arm  401  comprises: a spring plate  4011  and a spring plate  4012 , which are arranged one on top of another, with one end of the spring plate  4011  and one end of the spring plate  4012  both being fixed to a support  408  via a screw  405 , and a groove  409  being provided on that face of the spring plate  4012  which is in contact with the spring plate  4011 ; the first contact  403  is fixed to that side of the spring plate  4011  which is closer to the second contact arm  402 ; the second contact arm  402  is fixed to a support  408  via a screw  406 ; the second contact  404  is fixed to that side of the second contact arm  402  which is closer to the first contact arm  401 . 
     In an embodiment of the present invention, the spring plate  4011  and spring plate  4012  experience bending deformation towards the second contact arm  402  after being subjected to the action of a driving force; under the action of the driving force, the spring plate  4012  decreases the gap between itself and the spring plate  4011 . 
     Due to the presence of the groove  409 , the positions where the spring plate  4012  and spring plate  4011  are in contact with each other are two rectangular regions, avoiding bad contact caused by the surfaces of the spring plate  4011  and spring plate  4012  not being level. Once the first contact  403  is in contact with the second contact  404 , the spring plate  4011  and spring plate  4012  remain in a state of tight contact under the action of the driving force, until the driving force is removed, when the spring plate  4011  and spring plate  4012  move in the direction away from the second contact arm  402  under the action of their respective restoring elastic forces. 
     According to the embodiments described above, amongst the spring plates which are arranged one on top of another, the length difference or width difference of any two spring plates is in each case smaller than a preset standard error value. Thus, since the spring plates arranged one on top of another are fixed together at one end, the fixed ends are at the same electric potential, and the length difference and width difference of any two spring plates arranged one on top of another are both smaller than a preset standard error value, so the potential difference of various contact positions on two adjacent spring plates does not exceed a critical voltage for arcing, thereby avoiding the phenomenon of arcing between spring plates due to an excessively large potential difference, and increasing the safety of the contact structure. 
     According to the embodiments described above, the spring plates included in the first contact arm and second contact arm experience elastic deformation after being subjected to a driving force action, so that the two contacts come into contact with each other; once the driving action has been removed, each spring plate returns to a free state under the action of its own restoring elastic force, causing the two contacts to move away from each other, and realizing the separation of the two contacts. 
     According to the embodiments described above, to ensure that the spring plate has good conductivity and good elasticity, the spring plate is made of a copper alloy material; when the second contact arm has no elastic deformation capability, the second contact arm is a single conductor made of a copper alloy material. 
     As  FIG. 5  shows, one embodiment of the present invention provides a switch apparatus, comprising: at least one driver  501  and any contact structure  502  provided in an embodiment of the present invention; 
     the driver  501  is used for driving at least two spring plates included in the first contact arm in the contact structure  502 . 
     In one embodiment of the present invention, when the second contact arm in the contact structure  502  has elastic deformation capability, the driver  501  is further used for driving the second contact arm. 
     To clarify the realization of the contact structure and switch apparatus provided in embodiments of the present invention, the switch apparatus provided in an embodiment of the present invention is explained in further detail below in conjunction with the contact structure shown in  FIG. 2 . As  FIG. 6  shows, one embodiment of the present invention provides a switch apparatus, comprising: 
     the contact structure  20 , a first driver  601  and a second driver  602 ; 
     the first driver  601  is disposed on one side of the first contact arm  201  in the contact structure  20 , and is used for applying an electromagnetic driving force to the spring plate  2011  and spring plate  2012 ; and 
     the second driver  602  is disposed on one side of the second contact arm  202  in the contact structure  20 , and is used for applying an electromagnetic driving force to the spring plate  2021  and spring plate  2022 . 
     In one embodiment of the present invention, after being triggered, the first driver  601  applies an electromagnetic force, directed towards the second contact arm  202 , to the spring plate  2011  and spring plate  2012  respectively; under the action of the electromagnetic force applied by the first driver  601 , the spring plate  2011  and spring plate  2012  experience bending deformation towards the second contact arm  202 . After being triggered, the second driver  602  applies an electromagnetic force, directed towards the first contact arm  201 , to the spring plate  2021  and spring plate  2022  respectively; under the action of the electromagnetic force applied by the second driver  602 , the spring plate  2021  and spring plate  2022  experience bending deformation towards the first contact arm  201 . 
     The first contact  203 , driven by the spring plate  2011 , moves towards the second contact arm  202 , and the second contact  204 , driven by the spring plate  2021 , moves towards the first contact arm  201 , until the first contact  203  and the second contact  204  come into contact with each other. At this time, the spring plate  2012  is in tight contact with the spring plate  2011  under the action of the electromagnetic force of the first driver  601 , and the spring plate  2022  is in tight contact with the spring plate  2021  under the action of the electromagnetic force of the second driver  602 ; the spring plate  2011  and spring plate  2012  jointly carry the current flowing through the first contact arm  201 , and the spring plate  2021  and spring plate  2022  jointly carry the current flowing through the second contact arm  202 . When the first driver  601  and second driver  602  have stopped applying the electromagnetic force, the spring plate  2011  and spring plate  2012  move in a direction away from the second contact arm  202  under the action of their own elastic forces, the spring plate  2021  and spring plate  2022  move in a direction away from the first contact arm  201  under the action of their own elastic forces, and the first contact  203  and second contact  204  separate, driven by the spring plate  2011  and spring plate  2021 . 
     Based on the embodiments described above, embodiments of the present invention have at least the following beneficial effects: 
     1. In an embodiment of the present invention, the first contact arm comprises at least two spring plates, the first contact is disposed on the spring plate on the side closer to the second contact arm, and at least two spring plates included in the first contact arm experience elastic deformation under a driving action, causing the first contact to move, and realizing contact between the first contact and second contact. Since the first contact arm comprises at least two spring plates fixed to each other at one end, the elastic deformation capability of the first contact arm is increased; the spring plates are disposed one on top of another, to ensure that the cross-sectional area of the first contact arm meets the requirements of a large current. Thus, the elastic deformation capability of the first contact arm is increased while ensuring that the cross-sectional area of the first contact arm meets the requirements of a large current. Hence, in large-current applications, the first contact can be brought into contact with the second contact through elastic deformation of the first contact arm. This contact structure only has one pair of contacts, so the number of contacts is reduced. 
     2. In an embodiment of the present invention, the first contact arm is formed by arranging multiple spring plates one on top of another, so that a contact structure comprising just one pair of contacts can be used in the field of large currents. The amount of the precious metal silver is reduced by reducing the number of contacts, thereby reducing the cost of the switch apparatus in applications in the field of large currents. 
     3. In an embodiment of the present invention, the form of the second contact arm is not defined. The second contact arm may have no elastic deformation capability, so that the first contact arm causes the first contact to come into contact with or separate from the stationary second contact. Alternatively, the second contact arm may have elastic deformation capability, and the second contact arm causes the second contact to move while the first contact arm causes the first contact to move, realizing contact between or separation of the first contact and second contact. Thus, the form of the second contact arm can be determined flexibly according to demands, so the adaptability of the contact structure is increased. 
     4. In an embodiment of the present invention, when the second contact arm has elastic deformation capability, the second contact arm may have the same form as the first contact arm, being formed of multiple spring plates arranged one on top of another. The second contact arm may also be formed by arranging multiple spring plates in parallel and connecting them together in sequence. The form of the second contact arm may be chosen flexibly according to the installation position of the contact structure and the size of current carried, thereby further increasing the adaptability of the contact structure. 
     5. In an embodiment of the present invention, the length difference and width difference between spring plates arranged one on top of another are both smaller than a preset standard error value. Since the spring plates arranged one on top of another each have one end connected to the wiring board, those ends of the stacked spring plates which are connected to the wiring board are at the same potential. Since the length difference and width difference between spring plates arranged one on top of another are both smaller than a preset standard error value, it can be ensured that the potential difference at the position of contact between any two spring plates arranged one on top of another will not exceed a critical voltage for arcing, avoiding the phenomenon of arcing between two spring plates in contact with each other during the process of establishing contact between or separating the two contacts, and thereby increasing the safety of the contact structure and switch apparatus. 
     6. In an embodiment of the present invention, when multiple spring plates are arranged one on top of another, a groove may be provided on that face of any spring plate which is in contact with another spring plate. Thus, two spring plates are only in contact with each other at two ends; this can improve the contact between spring plates, ensure that the contact arm can transmit and withstand large currents normally, and increase the reliability of the contact structure and switch apparatus. 
     It must be explained that relationship terms such as “first” and “second” as used herein are merely intended to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms “comprise” and “include”, or any other variant thereof, are intended to cover non-exclusive inclusion, so that a process, method, article or device which comprises a series of key elements does not comprise these key elements alone, but also comprises other key elements which are not listed explicitly, or also comprises intrinsic key elements of this process, method, article or device. In the absence of further restrictions, a key element defined by the statement “comprises a . . . ” does not exclude the existence of another identical element in the process, method, article or device which comprises the key element. 
     Finally, it must be explained that the embodiments above are merely preferred embodiments of the present invention, which are merely intended to explain the technical solution of the present invention, and are not intended to define the scope of protection of the present invention. Any amendments, equivalent substitutions or improvements etc. made within the spirit and principles of the present invention shall be included in the scope of protection thereof.