Abstract:
An electrical connector for connecting the bare end of an insulated conductor with an electrical contact, including a connector housing containing a chamber in which are mounted a bus bar connected with the contact, and a clamping spring normally biased toward the bus bar. A retaining device maintains the spring in a retained open condition spaced from said bus bar, thereby to permit the conductor bare end to be introduced into the chamber toward a clamping position adjacent the bus bar. An operating member is displaced in a controlled manner to release the spring from its retained condition, whereby the spring biases the conductor toward electrical engagement with the bus bar. To remove the conductor, the operating member is operated again to displace the spring toward its open condition.

Description:
REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of International Application No. PCT/EP2009/061535 filed Sep. 7, 2009, claiming priority of German Application No. DE 20 2008 014 469.8 filed Oct. 31, 2008. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    An electrical connector for connecting the bare end of an insulated conductor with an electrical contact, including a connector housing containing a chamber in which are mounted a bus bar connected with the contact, and a clamping spring normally biased toward the bus bar. A retaining arrangement maintains the spring in a retained open condition spaced from said bus bar, thereby to permit the conductor bare end to be introduced into the chamber toward a clamping position adjacent the bus bar. An operating member releases the spring from its retained condition, whereby the spring biases the conductor toward electrical engagement with the bus bar. 
         [0004]    2. Description of Related Art 
         [0005]    It is well known in the prior art to provide electrical connectors for connecting the bare end of an insulated conductor with an electrical contact by pressing the conductor into engagement with a bus bar that is connected with the contact. 
         [0006]    However it is difficult in the known terminals to achieve good handling of the actuating element and, in particular, to achieve the opening position of the clamping spring with simple means in the disconnected state of the terminal, i. e. without a conductor, in which position a conductor can easily be inserted into, or removed from, the clamping site. 
         [0007]    It is the object of this invention to solve this problem. 
       SUMMARY OF THE INVENTION 
       [0008]    Accordingly, a primary object of the present invention is to provide an electrical connector for connecting the bare end of an insulated conductor with an electrical contact, including a connector housing containing a chamber in which are mounted a bus bar connected with the contact, and a clamping spring normally having a released closed condition biased toward the bus bar. Retaining means serve to retain the spring in a retained open condition spaced from said bus bar, thereby to permit the conductor bare end to be introduced into the chamber toward a clamping position between said clamping spring and the bus bar. An operating member is operable in a controlled manner to release the spring from its retained condition, whereupon the conductor is biased toward electrical engagement with said bus bar. 
         [0009]    According to another object of the invention, the movement of the operating member is controlled by cam track and follower means. In one embodiment, the cam follower is mounted on the operating member, and the cam track is provided on a control member that is connected for sliding movement with the housing. In a second embodiment, the cam track is mounted on the operating member, and the cam follower is mounted on a control member that is connected for sliding movement relative to the housing. 
         [0010]    According to a further object of the invention, the connector housing is provided with a plurality of clamping spring arrangements for biasing a number of conductors toward engagement with a plurality of bus bars, respectively. 
         [0011]    In accordance with a more specific object, the operating element is configured in a controlled contour-guided manner, which can primarily be achieved in that the controlled contour-guided configuration includes a control cam and a projection that engages in the control cam, in particular, a cam follower. 
         [0012]    The control cam can simply be configured such that the clamping spring can be retained in an open position so that the bare end of a conductor can be inserted into the open clamping site. 
         [0013]    According to a preferred embodiment, the control cam is provided in a movable element, in particular, a sliding element, and the projection is provided on the operating member. Alternatively, the control cam can be on the operating member, and the projection on the sliding element. 
         [0014]    According to another embodiment, a compact twin connector arrangement may be provided including a conductor insertion direction that is normal to the actuating direction, whereby two actuating elements are provided for separate actuation of two of the clamping springs that are arranged perpendicular to the lead insertion opening, respectively. Preferably, these two actuating elements are also configured in a controlled contour-guided manner. 
         [0015]    A particularly stable and compact configuration is achieved if the two actuating elements—preferably made of a synthetic plastic material—each act on one of the clamping springs, respectively, via a bracket arm—preferably consisting of metal. 
         [0016]    It is preferred that the operating element include a feed-through bore for the conductor, and that a stop be provided of the conductor insulation layer. The feed-through bore for the conductor preferably comprises a stepped configuration for this purpose and preferably has a surface in the contact area with the insulation of the lead that is used for transmitting force onto the clamping spring when pressure is applied to the conductor end. 
         [0017]    According to another embodiment, the one spring, in particular the clamping spring, is configured to generate a restoring force required in the cam for indexing when the pinion is removed from a recess of the cam by renewed pressure onto the conductor end. 
         [0018]    According to another feature, the connecting device of this type is configured such that the clamping site can be closed by applying pressure to the conductor end in the conductor insertion direction, and opened again by applying pressure to the conductor end once again. Connecting and disconnecting operations are thus achieved by simple constructive means without the use of tools. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0019]    Other objects and advantages of the invention will become apparent from a study of the following specification, when viewed in the light of the accompanying drawing, in which: 
           [0020]      FIG. 1   a  is a front elevation view of the electrical connector in the retained open condition receiving an insulated conductor,  FIG. 1   b  is a sectional view taken along line  1   b - 1   b  of  FIG. 1   a ,  FIG. 1   c  is a side elevation view corresponding to  FIG. 1   b , and  FIG. 1   d  is a perspective view of the connector of  FIG. 1   c    
           [0021]      FIG. 2   a  is a sectional view of the connector of  FIG. 1   b  when in the fully closed position,  FIG. 2   b  is a sectional view taken along line  2   b - 2   b  of  FIG. 2   a , and  FIG. 2   c  is a top view of the apparatus of  FIG. 2   a;    
           [0022]      FIGS. 3   a  and  3   b  are perspective views of the connector of  FIG. 2   a;    
           [0023]      FIG. 4   a  is a perspective view corresponding to  FIG. 1   b  with the conductor removed, and  FIG. 4   b  is a detailed partially exploded perspective view of the apparatus of  FIG. 4   a;    
           [0024]      FIG. 5  is an exploded view of the apparatus of  FIG. 4   a;    
           [0025]      FIGS. 6   a  and  6   b  are side elevation and perspective views of the cam control member of  FIG. 5 ; 
           [0026]      FIGS. 7   a  and  7   b  are side elevation and perspective views of a modification of the operating member of  FIG. 5 ; 
           [0027]      FIGS. 8   a - 8   d  are perspective views illustrating the assembly steps for producing a second embodiment of the electrical connector of the present invention,  FIG. 8   e  is an enlarged view of one of the clamping spring assemblies of  FIG. 8   a , and  FIG. 8   f  is a corresponding view with certain parts removed; 
           [0028]      FIG. 9  is a perspective view of one of the frame assemblies of  FIG. 8   b  with certain parts removed; 
           [0029]      FIG. 10   a  is a perspective view of the frame of  FIG. 9 ,  FIG. 10   b  is a perspective view of one of the cage members of  FIG. 9 ,  FIG. 10   c  is a perspective view of one of the operating brackets of  FIG. 9 ,  FIG. 10   d  is a perspective view of one of the operating members of  FIG. 9 ,  FIG. 10   e  is a perspective view of one of the clamping springs of  FIG. 9 , and  FIG. 10   f  is a perspective view of a second one of the operating brackets of  FIG. 9 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    Referring first more particularly to  FIGS. 1   b  and  5 , the electrical connector  1  includes a rectangular housing  11  formed of electrically insulating synthetic plastic material and containing a chamber C. Mounted for vertical sliding displacement in an opening  14  contained in the housing top wall is an operating member  15  having a top flange portion  16 , and an inclined bottom surface  15   a.  A projection  19  defining a cam follower extends rigidly from one side wall of the operating member, and a stop surface  15   b  is defined by an abutment on the opposite side wall. As shown in  FIG. 1   b , the operating member contains a vertical through bore  17  having at its upper end a counterbore  17   a  that defines a bottom wall  17   b.    
         [0031]    Mounted in the housing chamber C is a bent sheet metal cage  3  having a first orthogonally bent stop flange  3   a , and a pair of orthogonally bent parallel support flanges  3   b  and  3   c.  Secured to cage support flange  3   b  is one leg  7  of an inverted V-shaped leaf spring  6 . The other leg  8  of the leaf spring is biased by connecting arch portion  9  outwardly toward the vertical arm  5   a  of an L-shaped bus bar  5  that is secured to the other cage support flange  3   c.  The horizontal other arm  5   b  of the bus bar extends along the housing bottom wall and is fastened to a female contact  12  that downwardly through a protective housing portion  11  a toward a contact opening  13 . 
         [0032]    Connected by dovetail tongue and groove means  22  for sliding horizontal displacement relative to the housing end wall adjacent the conductor opening  14  is a control member  20 . A cam track  21  is provided on the face of the control member  20  for receiving the cam follower  19  mounted on the operating member  15 . As shown in  FIGS. 6   a  and  6   b , the cam track has a continuous generally-circular pattern surrounding a generally inverted-heart-shaped center portion  23  that contains a recess  24 . As will be described below, the cam track pattern is such that the follower  19  travels in a given direction around the center portion  23 . 
       Operation 
       [0033]    The spring leg  8  is normally biased toward the released closed condition of  FIGS. 2   a  and  4   a , wherein the free extremity of the leg  8  engages the bus bar  5 , and the operating member is elevated (by the engagement of spring leg  8  with inclined surface  15   a   0  to its upper extent of travel, as determined by the stop surface  15   b  ( FIGS. 2   a  and  3   a ). At this time, the cam follower  19  is in engagement with the uppermost point of the inverted heart-shaped center portion of the cam track. Upon the application of a downward force on the flange portion  16  of the operating member  15 , the spring leg  7  and the operating member  15  are displaced downwardly toward the retained open position of  FIG. 1   b . Simultaneously with this downward movement, the control member  20  is slidably displaced to the right in  FIGS. 3   a  and  3   b , owing to the cooperation between cam follower  19  and cam track  21 . When the cam follower  19  reaches a position beneath the recess  24 , the downward pressure on the operating member is reduced, whereupon the operating member is biased upwardly by spring leg  8  to cause the cam follower to be seated in recess  24 , thereby to retain the spring in the retained open condition. 
         [0034]    The conductor is now displaced downwardly as shown by the arrow x to cause the bare end of conductor  2  to extend into the clamping region  32  ( FIG. 1   b ). Upon further downward displacement of the conductor, the end of the insulation layer  18  engages the counterbore bottom wall, and as the conductor is further displaced downwardly, the spring leg  8  and the operating member are displaced downwardly, until cam follower projection  19  is displaced out of the recess  24 . Owing to the configuration of the cam track  21 , the operating member  20  is shifted relative to the housing  11 , and upon release o pressure on the flange  16 , the operating member is displaced upwardly until the extremity of spring leg  8  engages the bare conductor end and biases the same toward lateral electrical engagement with the bus bar  5 , thereby connecting the conductor with the contact  12 . 
         [0035]    To disconnect the conductor from the connector, the conductor is displaced downwardly to displace the spring leg  8  away from the bare conductor end, and the follower engages the cam track  21  to return the control member to a position in which the recess  24  is above the cam follower  21 , whereupon the operating member is released, and the spring is in the retained open condition of  FIG. 1   b.    
         [0036]    The clamping cage  3  is shown in a preferred—but not mandatory—configuration normal to the conductor insertion direction X in closed condition. But it can also just comprise less side walls and for example have a C shape in this sectional view. It is preferably configured in such a way that it at least performs the functions of supporting the clamping spring for absorbing the clamping and contact forces, and supporting the bus bar or bus bar function. It is preferred that a section of a bus bar  5  that serves as the section to be contacted by the lead end or as a contacting abutment projects into the clamping cage  3 . 
         [0037]    Alternatively, it is conceivable that the clamping cage  3  itself assumes an electricity-conducting function if it is made of, or coated with, an electro-conductive material. One or several stops  10  that are preferably designed as holes punched into the walls of the clamping cage  3  perform an opening limiting function for the clamping spring  6 . 
         [0038]    The operating member  15  itself encompasses a feed-through  17  through which the lead end  2  can be guided into the clamping site  32  between the bus bar  5  and the clamping spring  6 . The feed-through  17  may comprise a tapering or stepped reduction in cross-section, thus forming a stop for an insulation  18  of the lead which can optionally ensure the transmission of force from the lead end to the actuating element when the lead end is pressed down. 
         [0039]    The operating member  15  is configured as a pushbutton the one end of which rests on the clamping leg  8  and acts on it when pressed down and the other end of which is used to apply a pressure force to the pushbutton  15 , e. g. using a tool such as a screwdriver, is provided to move the free end of the clamping spring  6  from a position near, or in direct contact with, the bus bar  5  to a position more distant from the bus bar  5 , i. e. an opening position in which the lead end can inserted into the clamping site  32  or removed from the clamping site  32  ( FIG. 4 ). The pushbutton  15  can be moved parallel to the lead insertion direction X and is guided in a corresponding contour or hole  14  of the housing  11 . 
         [0040]    In addition, the actuating element  15  is particularly advantageously configured in a controlled contour-guided manner. This is achieved by equipping the actuating element  15  with a molded-on or attached protrusion, here a pinion  19 , which engages in a control cam  21  formed in a movable element, particularly in a sliding element  20 , wherein the sliding element  20  is movably guided like a carriage normal to the conductor insertion direction along (or here, in) a guide  22  of the housing  11 . 
         [0041]    The sliding element  20  and the guide  22  in the housing  11  are of the dovetail type (based on a corresponding groove-and-tongue principle) wherein the guide  22  extends perpendicular to the lead insertion direction X so that the sliding element  20  can be moved perpendicular to that direction (in  FIG. 1  perpendicular to the sheet plane). The control cam  21  is configured such that the pinion  19  can be locked—preferably audibly and/or by feel—into the movable sliding element  20  in the opening position for inserting or removing the conductor end  2  ( FIGS. 2 ,  4 ). 
         [0042]    It is also conceivable that the control cam  21  is configured such that the follower  19  also locks into place in the control cam in the closing position or contact position. Here the control cam  21  comprises a heart-shaped curvature (see  FIG. 6   a ) through which the follower  19  passes during opening and closing so that the sliding element  15  is moved accordingly perpendicular to the image plane. A heart-shaped center portion  23  whose recess  24  is used as a contact surface for the pinion  19  and the pushbutton  15  in the opening position is formed in the center of the control cam  21 . 
         [0043]    In the initial closed position in which the clamping spring  6  rests against the bus bar  5 , the follower  19  is positioned in the upper tip of the heart-shaped control cam  21  in the figure. The pushbutton  15  is pushed down in lead insertion direction X to open the clamping site  32  and to lock the pushbutton  15  into place in the opening position. In this process, the follower  19  moves through the control cam  21 , which also moves the sliding element  20  along. In the opening position, the sliding element  20  then moves proximate to the recess  24  where it remains after the pressure onto the operating member  15  lets off so that the operating member  15  is pushed upwardly into the recess  24  by the spring force of the clamping spring  24 . In this position, the conductor bare end  2  can be conducted into the clamping site  32 . 
         [0044]    Pressure is applied again to the operating member  15  to release the follower  19  or the opening position, respectively. Since the continuous control cam track  21  also comprises an appropriate height contour, the follower  19 , after leaving the recess  24  in the heart-shaped curve, moves in counterclockwise direction to the increasingly deeper region of the control cam  21  in the embodiment selected here ( FIG. 5 ) and passes through this region on the opposite side of where it moved during the push into the opening position. If the pressure onto the actuating element  15  stops, the clamping spring  6  is released and the conductor bare end is pressed against the bus bar  5  and make electric contact. 
         [0045]    Inverse arrangements are conceivable in which a control cam track  21  is provided in the actuating element  15  and a follower is provided in the sliding element  15  (see  FIG. 7  or  FIGS. 8-10  that show actuating elements with such control cams  21 ′ and in which the sliding element  20 ′ includes the follower  19 ′ (see  FIG. 8   e ). It is further conceivable to provide control cams  21  with other forms or contours and to arrange them on the another side of the operating member  15 . 
         [0046]    Referring now to  FIGS. 8   a - 8   f , according to an alternate embodiment of the invention, a number of clamping spring and bus bar arrangements may be mounted in a rectangular housing  27  ( FIG. 8   a ) containing on its top wall a plurality of conductor openings  114  for introducing the conductor bare ends in a direction normal to the operation of the operating members  25 . Referring to  FIG. 8   d , a plurality of devices are proved each having two clamping springs  6   a  and  6   b  arranged longitudinally of two vertically stacked operating members  25   a  and  25   b.  These operating members longitudinally displace upper and lower bracket members  26   a  and  26   b  ( FIGS. 10   c  and  10   f ) having abutments  30  at their ends for engagement with lateral tab portions  29  ( FIG. 10   e ) on the clamping springs, thereby to displace the spring legs  6 ′ away from the associated bus bars, respectively. Cam tracks  21 ′ on the operating members  25  ( FIG. 10   d ) engage the corresponding followers  19 ′ on the corresponding sliding members  20 ′ ( FIG. 8   f ) to shift the sliding members relative to frames  28  ( FIGS. 8   c  and  10   a ) and  128  ( FIG. 8   b ), thereby to retain the springs in the open retained condition. The sub assemblies of  FIG. 8   b  are then inserted within the housing open rear end to complete the assembly of  FIG. 8   a . The various bare ends of the insulated conductors are then inserted via openings  114  between the retained open spring ends and the bus bars in a manner corresponding to that shown in  FIG. 1   b.    
         [0047]    According to  FIGS. 8   a  to  8   f , the pushbutton  25  is configured in such a way that it is moved into a direction B that is normal to the lead insertion direction X. 
         [0048]    A bracket  26 , one section of which engages normal to the conductor insertion direction in an opening or window of the clamping cage  3 , is provided for this purpose on the operating member  25 . If the operating member  25  is moved in the direction B, the bracket  26  moves along with it and presses the clamping leg of the clamping spring away from the bus bar  5 . The clamping site therefore can be opened again by pushing the button. It is advantageous if the bracket  26  comprises a stepped contour  20  that acts on lateral projections  29  of the clamping spring. 
         [0049]    As can further be seen in  FIGS. 8 to 10 , a particular advantage of these terminals is that they are configured as multiple connectors, in this case twin connectors, wherein the clamping cage is designed such that it can house two clamping springs  6  and bus bars  5  arranged at a lateral offset to one another in actuating direction of the actuating element. Accordingly, two actuating elements  25   a  and  25   b  are provided. These actuating elements  25   a  and  25   b  are located on one side of the clamping cages  3   a,    3   b  to allow operation from the side, which is particularly advantageous. To still be able to open both clamping springs  6   a,    6   b  or clamping sites, the brackets  26   a,    26   b  are formed differently such that the one bracket  26   a  acts onto the one clamping spring  6   a,  and the other bracket  26   b  onto the other clamping spring  6   b.  The brackets  26  are preferably locked into place on the actuating elements  25  but they can also be formed in one piece with them. The actuating elements  25  may comprise a contour for applying a screwdriver to them. 
         [0050]    Actuating elements  25   a,    25   b  once again are configured in a controlled contour-guided manner, for which purpose two control cams  21  are formed directly onto the actuating elements  25   a,    25   b —again in heart-shaped configuration—that interact with followers  19 ′  FIG. 8   f ) of two sliding elements  20   a,    20   b  that are movably guided in respective guides in an outer housing  27 . A frame  28  that houses the clamping cages  3  is seen next to the outer housing  27  so that the housing here is made up of the frame components  28  and  128 , and the outer housing  27 . 
         [0051]    The actuating elements  25  once again can be locked into place in opening position so that the clamping sites can be opened separately to deliver the terminal in this condition to the customer and/or to make handling simpler. For stability reasons, the brackets  26  can be made of metal and the actual actuating elements  25  can be made of plastic. 
         [0052]    As is apparent from  FIG. 8 , the outer housing  27  can be designed such that it comprises multiple chambers, each of which receiving a single or twin connector. The figure shows three twin connectors in a single outer housing  27 . It would also be conceivable to open two clamping springs at the same time with one actuating element  25  if the latter comprised two brackets. 
         [0053]    The control cam track  21  is preferably configured so that the pushbutton can be released from its locked position just by pressing it in the conductor insertion direction X, e. g. to contact a conductor inserted into the clamping site, for which the clamping spring  6  has to be released. 
         [0054]    While the above embodiments refer to a connecting device in which the clamping spring acts as a compression spring, the invention can also be applied to embodiments in which the clamping spring is configured as a tension spring (not shown here). 
         [0055]    While in accordance with the provisions of the Patent Statutes the preferred forms and embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that changes may be made without deviating from the invention described above.