Patent Publication Number: US-11038289-B2

Title: Electrical connector

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the national stage application of PCT/EP2018/073638, filed Sep. 3, 2018, which claims priority to EP 17192169.5, dated Sep. 20, 2017. 
     The invention relates to an electrical connector for receiving at least one electrical conductor. For connection purposes, a bus bar and at least one clamp are provided. The clamp comprises a spring arm being moveable relative to the bus bar. The spring arm can be pre-loaded towards the bus bar so that an electrical conductor that is inserted into a gap between the bus bar and the spring arm can be mechanically secured, i.e., clamped and thereby connected to the bus bar by means of the spring arm. For connecting two or more electrical conductors by means of the connector, one or more clamps can be used, each clamp securing one or more of the conductors to the bus bar, thereby electrically connecting the conductors with each other. As the skilled person will understand, the clamp itself can participate in electrically connecting the conductors. 
     BACKGROUND 
     A general problem of the connector sketched above lies in the arrangement of the at least one clamp relative to the bus bar. Since these components need to cooperate with each other in order to safely secure an electrical conductor to the bus bar it is important to make sure that a suitable relationship between the components is maintained during operation, in particular under all circumstances. For example, the position of the clamp relative to the bus bar should not change regardless whether a conductor is connected or not. The position should also not change due to thermal and other mechanical factors. This restriction is a general challenge, and in particular when the connector should be compatible for various types of conductors that have different diameters. 
     When no conductor is connected, the spring arm usually directly cooperates with the bus bar, wherein the free end of the spring bar rests firmly on the bus bar. For connecting a conductor, it is necessary to lift the spring arm against a restoring force so that the conductor can be inserted into the clamp. Sometimes it is sufficient to push an end section of the conductor against the spring arm, wherein the spring arm is displaced in response and the necessary gap to insert the conductor into the clamp is formed. However, this is not always possible. Especially light flexible or twisted conductors usually cannot be inserted into the clamp and exert the force necessary to displace the spring arm. This means that the user of the connector needs to manually position the spring arm at some distance away from the bus bar, such that a suitable gap between the spring arm and the bus bar is formed. Then the electrical conductor can be inserted into the clamp. Afterwards, the spring arm can be released, so that the spring arm secures the conductor on the bus bar. 
     The connector can comprise a housing with at least one opening for inserting an electrical conductor, in particular an end section of an electrical conductor, into the housing. The clamp and the bus bar can be arranged inside the housing. In order to fulfil the above mentioned requirement of maintaining a predefined relationship between the clamp and the bus bar, i.e., the position of the clamp relative to the bus bar, the clamp and the bus bar are often secured inside the housing, wherein the bus bar and/or the clamp are mechanically connected to the housing. This mechanical connection is often problematic since mechanical stress can be exerted on the housing, in particular when the spring arm of the clamp is moved. Undesired deformation processes of the housing can result from mechanical stress exerted on the housing. Consequently, the position of the clamp and/or the bus bar can change and the predefined relationship between the bus bar and the clamp be lost. Moreover, when the housing is formed from a plastic material, the risk of deformation processes is not only present because of mechanical stress exerted on the housing, but also because of thermal influences. As the skilled person will understand, this is undesired because an electrical conductor secured in the connector can be released and disconnected unintentionally during operation of the connector, thus leading to unsafe electrical conditions (e.g., malfunction, short circuit). 
     SUMMARY 
     An example embodiment of an electrical connector includes a bus bar and at least one clamp, wherein the at least one clamp comprises a spring arm moveable relative to the bus bar. The spring arm cooperates with the bus bar to secure an electrical conductor to the bus bar when the spring arm is in a connecting position, wherein the clamp is directly mounted to the bus bar. In this way, a predefined relationship between the clamp and the bus bar is maintained and no external support elements are necessary. The clamp and the bus bar can thus be accommodated in a housing without substantially exerting mechanical stress on the housing, in particular when the spring arm is deflected against a restoring force. 
     The term “directly mounted” means that at least a mechanical connection is formed without any intermediate parts such as adaptors which are prone to negatively influence the positional relationship between the bus bar and the clamp. In particular, the clamp is mechanically connected to the bus bar by means of an integral section of the clamp. 
     A direct mounting can also have advantages in electrical terms since the spring arm can be electrically connected to the bus bar by means of the direct mechanical mounting. In cases where a direct electrical connection between a conductor and the bus bar is lost, the spring arm can establish the electrical connection between the conductor and the bus bar. For this reason the clamp and the bus bar are preferably formed from an electrically conducting material, i.e. a metal. They can consist only of a metal. The bus bar preferably comprises copper. The clamp preferably comprises a steel, in particular a stainless steel. 
     The connecting position of the spring arm comprises any position in which the spring arm cooperates with the bus bar. The spring arm can either directly cooperate the bus bar, which is usually the case when no conductor is inserted into the clamp. However, the spring arm can also indirectly cooperate with the bus bar, in particular when a conductor is clamped between the spring arm and the bus bar, thereby securing the conductor to the bus bar. In contrast, a disconnecting position is a position in which the spring arm is held at a distance away from the bus bar without cooperating with a conductor. 
     According to one embodiment, the at least one clamp is latched to the bus bar. This can be accomplished by means of a snap-fit connection. For example the clamp and/or the bus bar can comprise one or more locking members for latching the clamp to the bus bar. A locking member of the clamp can be formed by a projection which engages with the bus bar, in particular behind the bus bar. 
     According to another embodiment, the bus bar is caught and/or clamped in at least one integral mounting section of the at least one clamp. The mounting section can be a cage portion being configured to receive the bus bar and thereby mount the clamp to the bus bar. In the mounted condition, the bus bar can be caught in the cage portion. Furthermore, the bus bar can have no support of a housing of the connector. 
     The at least one mounting section is formed by a support arm and a locking arm, wherein the bus bar extends between the support arm and the locking arm. In this way, the clamp grasps the bus bar. The spring arm is preferably arranged above the mounting section so that the spring arm can exert a force on the bus bar against the support arm of the mounting section when the spring arm is in the connecting position. 
     According to another embodiment, the at least one clamp comprises two mounting sections arranged on two opposite sides of the spring arm. The mounting of the clamp is thus mechanically very stable with respect to the spring arm, wherein any forces exerted by the clamp on the bus bar and vice versa are transmitted at two distant points around the spring arm. This is especially useful for maintaining a predefined relationship between the bus bar and the spring arm. 
     The bus bar can comprise at least one outer recess defining a predetermined position at which the at least one clamp is mounted to the bus bar. The clamp can thus only be secured at a predefined position which simplifies mounting the clamp to the bus bar (poka-yoke principle). If more than one clamp is mounted to the bus bar, a single recess can receive portions of two adjacent clamps. The number of necessary recesses for determining the mounting positions can thus be kept low, wherein stability of the bus bar is not substantially sacrificed and production resources are saved. 
     The bus bar can comprise at least one ramp section associated with a free end of the spring arm, wherein the ramp section forms a contact portion for an electrical conductor. The spring arm can comprise a free end which is bent towards the bus bar, and in particular towards the ramp section of the bus bar. Alternatively or additionally, the free end of the spring arm can comprise a contact edge facing the bus bar, and preferably, the ramp section of the bus bar. 
     According to another embodiment, the spring arm comprises a base portion which is integrally connected to a frame portion of the at least one clamp, and wherein the spring arm further comprises an extension portion which is integrally connected to the frame portion opposite from the base portion. The extension arm can act as a stabilizer for the clamp, in particular when the spring arm is moved from the connecting position towards a disconnecting position in which the spring arm exerts a greater force onto the frame portion. The extension arm can also define a maximum distance the spring arm can be moved away from the bus bar. This can ensure that the spring arm is not deflected beyond its elastic limit. The extension arm can also conduct excess forces to a housing of the connector during spring arm movement, thereby acting as a support arm for the clamp. The spring arm and/or the base portion can be resilient. The base portion can comprise a curved section. 
     According to another embodiment, the bus bar is at least partially flush with the at least one clamp. This allows for a very compact design of the connector and simplifies assembly of the connector. 
     According to another embodiment, the at least one clamp is mounted or mountable to the bus bar in a first direction, wherein the spring arm exerts a force on the bus bar in a second direction when the spring arm is in the connecting position, and wherein the first and second directions are substantially the same or substantially opposite. In the latter case, it is effectively impossible that the bus bar is dismounted due to the spring arm exerting a force onto the bus bar. In the case that the first and second directions are substantially the same, mounting of the clamp can be simpler, for example, when the spring arm of the clamp is displaced during mounting in response to an engagement with the bus bar. In any case, during assembly of the connector the spring arm can be lifted when the clamp is mounted to the bus bar. This can simplify the mounting as such and avoids any damage of the bus bar caused by the spring arm, in particular when the free end of the spring arm comprises a sharp edge. 
     The bus bar comprises at least one ramp section associated with a free end of the spring arm, wherein the ramp section forms a contact portion for an electrical conductor, and wherein the ramp section is inclined in the second direction in which the spring arm can exert a force on the bus bar. 
     The bus bar and/or the at least one clamp can have an at least substantially rectangular outer shape. This can simplify an assembly of the connector and is advantageous for arranging the bus bar and/or the clamp inside a housing of the connector. 
     The connector comprises a housing, wherein the bus bar and the clamp are arranged inside the housing. The connector can comprise more than one clamp mounted to the bus bar, wherein each clamp can define a connection terminal for an electrical conductor. The clamps can be mounted adjacent to each other. It is also possible that the connector comprises more than one bus bar, wherein clamps associated with a defined electrical potential are mounted to corresponding bus bars. 
     The connector is configured to connect all types of electrical conductors, i.e., rigid cables, twisted cables, stranded cables and stranded flexible cables, wherein the cross section area of the cables can be for example between 0.13 and 4 mm 2 . 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention is described further in the following by means of exemplary embodiments shown in the enclosed drawings in which 
         FIG. 1  shows a perspective view of an electrical connector with three connection terminals; 
         FIGS. 2 a -2 c    show perspective views of electrical connectors with two ( FIG. 2 a   ), three ( FIG. 2 b   ), and five ( FIG. 2 c   ) connection terminals; 
         FIG. 3  shows a perspective explosion view of the electrical connector of  FIG. 1 ; 
         FIGS. 4 a -4 j    show perspective views illustrating an assembly of the electrical connector of  FIG. 1 ; 
         FIGS. 5 a , 5 b    show perspective views of a clamp of an electrical connector with a spring arm of the clamp in a connecting position ( FIG. 5 a   ) and in a disconnecting position ( FIG. 5 b   ); 
         FIGS. 6 a -6 c    show perspective views illustrating a mounting of three clamps to a bus bar for the connector of  FIG. 1 ; 
         FIG. 7 a    shows a perspective view of the electrical connector of  FIG. 1 ; 
         FIG. 7 b    shows a cross-sectional view of a slider and an adjacent portion of the housing of the electrical connector of  FIG. 1 ; 
         FIG. 7 c    shows a cross-sectional perspective view of the electrical connector of  FIG. 7   a;    
         FIG. 8 a    shows a cross-sectional side view of the electrical connector of  FIG. 1 ; 
         FIG. 8 b    shows a perspective view of a bus bar of the electrical connector of  FIG. 1 ; 
         FIG. 8 c    shows a perspective cross-sectional view of the bus bar of  FIG. 8   b;    
         FIG. 8 d    shows a top view of the bus bar of  FIG. 8   b;    
         FIGS. 9 a , 9 b    show cross-sectional side views of the connector of  FIG. 1  in different operational states; 
         FIG. 9 c    shows a cross-sectional top view of the connector of  FIG. 1 ; 
         FIGS. 10 a ,10 b    show perspective cross-sectional views of the connector of  FIG. 1  in different operational states; 
         FIG. 10 c    shows a cross-sectional top view of the connector of  FIG. 1 ; 
         FIG. 11  shows a top view of the connector of  FIG. 1 ; 
         FIG. 12  schematically illustrates a sliding guide of a slider for the electrical connector of  FIG. 1 ; 
         FIG. 13  shows a cross-sectional perspective view of the connector of  FIG. 1 ; 
         FIG. 14  shows a cross-sectional side view of the connector of  FIG. 9   b,  
         wherein the cross-sectional plane is shifted compared to  FIG. 9   b;          

         FIG. 15 a    shows a cross-sectional perspective side view of the connector of  FIG. 9 b   , wherein the cross-sectional plane is shifted compared to  FIG. 9   b;    
         FIG. 15 b    shows a cross-sectional perspective side view of the connector of  FIG. 9 a   , wherein the cross-sectional plane is shifted compared to  FIGS. 9 a   ; and 
         FIG. 16  shows a cross-sectional top view of the connector of  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION 
     In the following, identical or similar features will be identified by the same reference signs. 
     An electrical connector  10  having three connection terminals  12  is shown in  FIG. 1 , wherein the perspective view is directed on a top side of the connector  10 . An electrical conductor  14  is received in the connector  10  and inserted to a middle terminal  12 .  FIG. 13  is a perspective cross-sectional view of the connector of  FIG. 1 , wherein the cross-sectional plane is substantially parallel to the conductor  14 . The connector  10  comprises an outer housing element  16  and a bus bar  22  arranged inside the outer housing element  16  (cf.  FIG. 13 ). For each terminal  12 , a clamp  24  is arranged inside the outer housing element  16  and directly mounted to the bus bar  22 , as will be explained further. The outer housing element  16  has a substantially rectangular shape that substantially defines the outer shape of the connector  10 . The outer housing element  16  preferably comprises a transparent material so that the interior of the connector  10 , i.e., the clamps  24  and the bus bar  22  (cf.  FIG. 13 ) can be seen from outside the outer housing element  16 . 
     For each terminal  12 , an associated slider  18  extends into the outer housing element  16 . Each slider  18  is moveable independently from each other relative to the outer housing element  16  along a second axis B between a closed position and an open position, as will be explained further. 
       FIG. 2 b    shows the connector  10  of  FIG. 1  in a different perspective view. In a comparison,  FIG. 2 a    shows a connector  20  having two terminals  12 .  FIG. 2 c    shows a connector  30  having five terminals  12 . 
       FIG. 3  shows a perspective explosion view of the electrical connector  10  of  FIG. 1 . In addition to the bus bar  22  and the clamps  24 , an inner housing element  26  is provided to be arranged inside the outer housing element  16 . 
       FIGS. 4 a  to 4 j    show perspective views illustrating an assembly of the electrical connector  10  of  FIG. 1 . Before explaining the assembly in detail, the clamp  24  and the bus bar  22  are described in detail with reference to  FIGS. 5 a , 5 b , 6 a , 6 b   , and  6   c.    
     The clamp  24  comprises a spring arm  28  moveable along a first axis A between a connecting position and a disconnecting position. In  FIG. 5 a   , the spring arm  28  is in a connecting position. In  FIG. 5 b   , the spring arm  28  is in a disconnecting position. The movement of the spring arm  28  can be substantially limited along the first axis A, i.e. the spring arm  28  is moveable along the first axis A. However, the movement of the spring arm  28  is not necessarily strictly linear but can follow a curved trajectory. 
     The spring arm  28  preferably comprises a curved and resilient base portion  32  which is integrally connected to a frame portion  34  that is substantially U-shaped. The spring arm  28  preferably further comprises an extension portion  36  which is integrally connected to the frame portion  34  opposite from the base portion  32 . The spring arm  28  preferably further comprises a contact edge  37  extending perpendicular to the first axis A. 
     The clamp  24  preferably comprises two integral mounting sections  38 ,  38 ′ arranged on two opposite sides of the spring arm  28 . In the embodiment of  FIGS. 5 a  and 5 b   , the two opposite sides are lateral sides of the spring arm  28 , wherein the mounting sections  38 ,  38 ′ are integral with the frame portion  34  and preferably generally identical. Each mounting section  38 ,  38 ′ is formed by a support arm  42 ,  42 ′ and a locking arm  44 ,  44 ′, all preferably extending substantially parallel to the second axis B. The bus bar  22  extends between the support arm  42 ,  42 ′ and the locking arm  44 ,  44 ′ when the clamp  24  is mounted to the bus bar  22 , as indicated in  FIG. 6 c   . In this way, the clamp  24  grasps the bus bar  22  at two distant points. The spring arm  28  is preferably arranged above the mounting sections  38 ,  38 ′ so that the spring arm  28  exerts a force on the bus bar  22  against the support arms  42 ,  42 ′ of the mounting sections  38 ,  38 ′ when the spring arm  28  is in the connecting position, as shown in  FIG. 8 a   . Each locking arm  44 ,  44 ′ comprises a projection  46  which engages behind the bus bar  22  when the clamp  24  is mounted to the bus bar  22 , as shown for example in  FIG. 6 c   . The projection  46  is preferably adapted for a snap-fit connection between the bus bar  22  and the clamp  24 . 
     Starting from the situation shown in  FIG. 6 a   , the clamp  24  is directly mounted to the bus bar  22  by introducing the bus bar  22  into the mounting sections  38 ,  38 ′ until it is latched to the clamp  24 , wherein the bus bar  22  is clamped in the mounting sections  38 ,  38 ′, as shown in  FIG. 6 c   . In the mounted condition, the projections  46  engage with recesses  48  formed on a narrow side of the bus bar  22 . On the opposite narrow side of the bus bar  22 , the frame portion  34  of the clamp  24  engages with two further recesses  52 . The recesses  48 ,  52  of the bus bar  22  define mounting positions for the clamp  24 . When mounted to the bus bar  22 , the clamp  24  is preferably partially flush with the bus bar  22  with respect to one or all narrow sides of the bus bar  22 . 
     The first axis A and the second axis B are preferably perpendicular to each other when the clamp  24  is mounted to the bus bar  22 . The clamp  24  is mounted to the bus bar  22  in a first direction dl preferably substantially parallel to the second axis B, wherein the spring arm  28  can exert a force on the bus bar  22  in the first direction dl when the spring arm  28  is in the connecting position ( FIG. 6 a   ). The spring arm  28  can be displaced by the bus bar  22  during mounting. In another embodiment (not shown), the clamp  24  is mounted to the bus bar  22  in a second direction which can be substantially opposite to the direction in which the spring arm  28  can exert a force on the bus bar  22 , i.e. the first direction dl. In the latter case, it would be effectively impossible that the bus bar  22  is dismounted due to a force exerted onto the bus bar  22  by the spring arm  28 . During mounting the clamp  24  to the bus bar  22 , the spring arm  28  is preferably held in the disconnecting position as shown in  FIG. 6 a    and  FIG. 6 c   . It is, however, also possible to let the spring arm  28  move away in response to the bus bar  22  during mounting. 
       FIG. 6 b    shows the bus bar  22  of  FIGS. 6 a  and 6 c    with three clamps  24  mounted adjacently to the bus bar  22 , thereby partially forming three terminals  12  of the connector  10  of  FIG. 1 . Each clamp  24  is mounted to the bus bar  22  in the same way. 
     Coming back to  FIGS. 4 a  to 4 j   ,  FIGS. 4 a  to 4 c    illustrates mounting of three clamps  24  to the bus bar  22 , as explained above. The bus bar  22  is then introduced into the outer housing element  16  ( FIG. 4 d   ) and arranged inside the outer housing element  16  in the position shown in  FIG. 4 e   . Afterwards, the inner housing element  26  is introduced into the outer housing element  16  ( FIG. 4 f   ) until it latches to the outer housing element  16  ( FIG. 4 g   ). Sliders  18  are introduced into the outer housing element  16  thereafter ( FIGS. 4 h  to 4 j   ), which finally results in the assembled connector  10  of  FIG. 1  ( FIG. 4 j   ). 
       FIG. 7 a    shows a perspective view of the electrical connector  10  of  FIG. 1  with the perspective view on a bottom side of the connector  10 . As already mentioned above, the outer housing element  16  preferably comprises a transparent material so that the clamps  24  and the bus bar  22  can be seen from outside the outer housing element  16 . This aspect cannot be seen in  FIG. 7 a   . However,  FIG. 7 c    shows the connector  10  of  FIG. 7 a    along a cross-section through the connector  10 , wherein the cross-sectional plane is indicated by crosshatched areas. Each terminal  12  is associated with an opening  54  in the outer housing element  16  for introducing an electrical conductor  12  into a corresponding clamp  24  of the terminal  12 . As can also be seen in  FIG. 7 a   , the outer housing element  16  comprises at least one further opening  56  for latching the inner housing element  26  to the outer housing element  16 , wherein the bus bar  22  with the mounted clamps  24  is secured in the outer housing element  16  between the sliders  18  and the openings  54 . The bus bar  22  with the clamps  24  is preferably received in the inner housing element  26 . 
     The openings  54  are circular and are easily visible for a user due to the substantially circular shape of the adjacent portion of the outer housing element  16 , i.e. a portion of the outer housing element  16  has a shape that corresponds to the shape of the openings  54  and the circular cross-section of the conductor  14 ,  14 ′ to be inserted. The openings  54  can thus provide good mechanical support for the inserted conductor  14 ,  14 ′. Furthermore, the number of available terminals  12  can intuitively be recognized by a user. 
     Each opening  54  communicates with a circular channel  114  which forms a guiding channel for the conductor  14  during insertion (cf.  FIGS. 10 a , 10 b   , and  10   c ). The channel  114  prevents the conductor  14  of slipping around the spring arm  28  when being introduced in the opening  54 . The diameter of the channel  114  can be variable so as to improve guidance of the conductor  14  towards the free end  68  of the spring arm  28 . The diameter of the channel can gradually and/or partially be reduced towards the ramp section  66  and the free end  68 . The minimum diameter of the channel  114  can be smaller than a diameter of the opening  54  ( FIGS. 10 a  and 10 b   ). The inner shape of the channel  114  can be substantially circular, in particular oval. Similar shapes are possible. 
       FIG. 7 b    shows a cross-sectional view of the slider  18  and an adjacent portion of the outer housing element  16 , wherein the cross-sectional plane is perpendicular to the plane indicated through the crosshatched areas in  FIG. 7 c   .  FIG. 7 b    will be explained further below. 
     As shown in  FIG. 1 , the slider  18  comprises an operating portion  58 . The operating portion  58  comprises a press surface  62  extending substantially perpendicular to the second axis B. The press surface  62  preferably forms an outer side of the connector  10 , wherein the outer side is preferably a narrow side of the connector  10 . The press surface  62  has several openings  64  having different sizes. The openings  64  can be formed as recesses. 
     Further details of the bus bar  22  are described with reference to  FIGS. 8 a  to 8 d   .  FIG. 8 c    shows a cross-sectional view of the bus bar  22  of  FIG. 8 b   , wherein the cross section is along the axis C shown in  FIG. 8 b   . The bus bar  22  comprises ramp sections  66 , wherein each ramp section  66  is associated with a free end  68  of the spring arm  28  of one of the clamps  24  mounted to the bus bar  22 . Each ramp section  66  forms a contact portion for an electrical conductor  14 , wherein the ramp section  66  is preferably inclined in the first direction dl in which the spring arm  28  can exert a force on the bus bar  22  when the spring arm  28  is in the connecting position ( FIG. 6 a , 6 b   ). 
     The spring arm  28  cooperates with the bus bar  22  when the spring arm  28  is in the connecting position, as shown in  FIGS. 8 a , 9 b  and 10 a   . In particular, the free end  68  of the spring arm  28  rests on the associated ramp section  66  when the spring arm  28  is in the connecting position. When the spring arm  28  is in the connecting position, the slider  18  is in the closed position in which the slider  18  is preferably substantially received in the outer housing element  16 . 
     In  FIG. 9 a    and  FIG. 10 b   , the spring arm  28  is positioned at a predetermined distance away from the bus bar  22 . This is a disconnecting position of the spring arm  28 , wherein an electrical conductor  14  can be inserted through the opening  54  of the outer housing element  16  into a gap  72  formed between the free end  68  of the spring arm  28  and the bus bar  22  or to be removed therefrom ( FIG. 10 b   ). The gap  72  can have a size of approximately 3 mm. 
     In order to move the spring arm  28  from the connecting position into the disconnecting position, the slider  18  is moved from the closed position into the open position in which the slider  18  preferably protrudes out of the outer housing element  16  as shown in  FIG. 9 a    and  FIG. 10 b   . In the open position, the slider  18  can protrude out of the outer housing element  16  by approximately 6 mm. The force necessary for moving the spring arm  28  is exerted via two opposite sliding guides  74  of the slider  18 , wherein one of these sliding guides  74  is illustrated in the cross-sectional views of  FIGS. 14, 15   a  (slider  18  in closed position) and  15   b  (slider  18  in open position). The sliding guides  74  are preferably generally identical. The sliding guides  74  cooperate with the spring arm  28  such that the movement of the slider  18  along the second axis B translates into the movement of the spring arm  28  along the first axis A, as illustrated by  FIGS. 9 a , 9 b , 10 a , 10 b   ,  14 ,  15   a , and  15   b.    
     The sliding guides  74  are preferably formed at two opposite side arms  76 ,  76 ′ of the slider  18 , wherein the side arms  76 ,  76 ′ preferably extend parallel to the second axis B and grasp the clamp  24 , as shown, e.g., in  FIG. 9 c   . As mentioned above, in  FIGS. 14, 15   a , and  15   b  only one sliding guide  74  is visible. The sliding guide  74  preferably comprises three linear or curved segments  78 ,  78 ′,  78 ″, as shown in  FIG. 12 . As indicated in  FIGS. 14 and 15   a , the sliding guide  74  cooperates with the spring arm  28  at or close to a junction between segments  78  and  78 ′ when the spring arm  28  is in the connecting position. As further shown in  FIG. 15 b   , the sliding guide  74  cooperates with the spring arm  28  on segment  78 ″ when the spring arm  28  is in the disconnecting position. Segments  78  and  78 ″ are preferably parallel to the second axis B and can define maximum positions of the spring arm  28 . When the slider  18  is in a position between the open and the closed position, the spring arm  28  cooperates with the sliding guide  74  on segment  78 ′, which forms a ramp section of the sliding guide  74 . The sliding guide  74  can be designed differently and can comprise for example nonlinear portions as indicated for segment  78 ′ in  FIG. 12 . It is also possible that the sliding guide  74  does not cooperate with the spring arm  28  when the spring arm  28  is in the connecting position. In this way, the spring arm  22  is free to cooperate with the bus bar  22 . Preferably, the sliding guide  74  can lift the spring arm  28  in a direction against a restoring force of the spring arm  28 , wherein the sliding guide  74  does not exert a force on the spring arm  28  in the opposite direction, i.e., a direction of pre-load of the spring arm  28 . 
     The sliding guide  74  cooperates with a preferably convex support surface  82  of the spring arm  28  ( FIG. 5 b   ), wherein the support surface  82  is formed at a lateral tongue  84  bent away from the free end  68  of the spring arm  28 . Preferably, the spring arm  28  comprises two opposite lateral tongues  84 ,  84 ′, as shown in  FIG. 5 b   , wherein each tongue  84 ,  84 ′ forms a support surface  82  for an associated sliding guide  74  of the slider  18 . 
     As can be seen, e.g., in  FIG. 8 a   , the spring arm  28  is preferably bent away from the bus bar  22  at portion  108  substantially half-way between the resillent portion  32  and the free end  68 . Furthermore, the spring arm  28  is preferably bent towards the bus bar  22  at portion  110 . Therefore, an indentation  112  is formed at the spring arm  28  which, e.g., improves resilience of the spring arm  28 . Furthermore, the segment between the portion  108  and the portion  110  can act as a stop surface for the spring arm  28  which can flatly engage with the frame portion  34  when the spring arm  28  is in the disconnecting position, thereby defining a maximum displacement of the spring arm  28  ( FIGS. 9 a  and 5 b   ). 
     For securing the slider  18  in the closed position, the slider  18  preferably comprises V-shaped recesses  86  which engage with preferably wedge-shaped projections  88  formed at the inner housing element  26  when the slider  18  is in the closed position ( FIGS. 9 c  and 10 c   ). The projections  88  can alternatively be formed at the outer housing element  16 . In this way, the slider  18  latches to the housing of the connector  10  when the slider  18  is in the closed position. The recesses  86  and projections  88  form first locking members of the connector  10 . 
     The connector  10  further comprises second locking members for securing the slider  18  in the open position. The second locking members are preferably formed by openings  92  of the slider  18  and the projections  88  of the inner housing element  26 . The openings  92  and the projections  88  engage when the slider  18  is in the open position, wherein the slider  18  preferably cannot be moved further away from the outer housing element  16  ( FIGS. 9 c  and 10 c   ). For this purpose, the projection  88  and the engaging portion of the slider  18  adjacent to the opening  92  can be inclined so as to further improve locking of the slider  18  in the closed position. The skilled person will understand that other, additional or modified means of mechanical locking, i.e. latching can be provided. 
     As shown for example in  FIGS. 1 and 7   a , the outer housing element  16  can comprise two opposite recesses  94  arranged adjacent to the openings  54  of the outer housing element  16  on two opposite narrow sides that extend parallel to the second axis B. Further recesses  96  (cuttings) can be provided on the top side ( FIG. 1 ). 
     With reference to  FIGS. 11 and 16 , wherein  FIG. 16  is a cross-sectional view of the connector  10  of  FIG. 11 , the outer housing element  16  preferably comprises control windows  98 , wherein the position of an end section of an electrical conductor  14 ,  14 ′ can be monitored from outside the outer housing element  16 . In this way, the user can check whether the conductor  14 ,  14  is passed through the corresponding clamp  24  so that the spring arm  28  can be moved into the connecting position thereby securing the conductor  14 ,  14 ′ to the bus bar  22 . The control windows  98  do not need to be formed separately if the corresponding housing portions are formed of a transparent material. In the embodiment shown in  FIG. 11 , the inner housing element  26  and the outer housing element  16  are formed by a transparent material. A distance  100  shown in  FIG. 11  can be approximately 11 mm. 
     With reference to  FIG. 1 , the operating portion  58  of the slider  18  can comprise two ridges  101  arranged on opposite sides of the operating portion  58 , wherein each of the two ridges  101  projects outwardly away from the slider  18  and extends substantially perpendicular to the second axis B. The operating portion  58  of the slider  18  further comprises a support surface  102  extending substantially perpendicular to the plane defined by the first axis A and the second axis B, wherein the support surface  102  forms a first outer side of the connector  10 , and wherein one of the ridges  101  is arranged adjacent to the support surface  102 . The support surface  102  is preferably guided in the outer housing element  16  so that a force exerted onto the support surface  102  is compensated by the outer housing element  16  ( FIG. 7 b   ). For this purpose, the outer housing element  16  preferably has a convex surface  104  arranged between the lateral edges of the slider  18  which preferably have further convex surfaces  106  for lowering sliding resistance when a force is exerted onto the support surface  102 . The support surface  102  can be recessed as shown in  FIGS. 1 and 7   a  so as to further improve support for the user. 
     As is also shown in  FIG. 7 b   , a recess  56 ′ is provided in the outer housing element  16  for latching the outer housing element  16  to the inner housing element  26 . 
     The connector  10  of  FIG. 1  has a height of 8.3 mm, a width of 18.6 mm and a length of 18.7 mm. The connector  10  is thus very compact. However, the connector  10  can also have other dimensions. 
     The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this invention. The scope of legal protection given to this invention can only be determined by studying the following claims.