Abstract:
A compact spring-biased connector includes a housing having a chamber containing a conductive bus bar, a clamping spring normally having an expanded clamping condition for biasing a conductor bare end toward electrical engagement with the bus bar, and a release lever pivotally connected with the housing for displacement from a normally closed clamping position toward an open position, such that a lateral projection on the clamping lever operates the clamping spring toward a compressed open condition, thereby permitting removal of the conductor bare end from the housing chamber. The clamping spring is a compression V-shaped leaf spring having a stationary support leg and a movable clamping leg, with the lateral operating projection extending within the chamber to engage the spring clamping leg adjacent its juncture with the support leg.

Description:
REFERENCE TO RELATED APPLICATIONS 
     This application is a national stage application under 35 C.F.R. §371 of the PCT International Application No. PCT/EP2014/057531 filed Apr. 14, 2014, which claims priority of the German application No. DE 20 2013 101 582.2 filed Apr. 15, 2013. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a spring-biased connector including a housing having a chamber containing a conductive bus bar, and a clamping spring normally having an expanded clamping condition for biasing a conductor bare end toward electrical engagement with the bus bar. A release lever is pivotally connected with the housing for displacement from a normal closed clamping position toward an open position, whereby a lateral projection on the clamping lever operates the clamping spring from the expanded clamping condition toward a compressed open condition, thereby to permit removal of the conductor bare end from the housing chamber. 
     Description of Related Art 
     It is known in the prior art to provide electrical connectors with spring-biased clamping elements for clamping electrical conductors toward an electrical contact. The electric conductors are solid wire conductors, stranded conductors, or conductive sleeves, for example, in which stranded conductors are clamped, in order to protect the strands from damage. To ensure good electrical conductivity, the wires of the conductor are usually made of a copper-containing material or copper, and are relatively soft as compared to the spring steel used for the clamping springs. In this connection, the miniaturization of the electronics requires ever new installation space-saving concepts. 
     The Chiang U.S. Pat. No. 8,262,422 B1 discloses a spring-biased clamping element, in which an electric conductor is clamped at a clamping point in a spring housing between a bus bar and a spring arm. The spring arm is pivotable about a fixed axis. To release the electric conductor, the spring arm includes an extension, on the outside of which a connecting piece is provided, which engages in a groove of a lever pivotable about this same axis. As a result, the spring arm with the lever is pivotable against its restoring force and the electric conductor may be removed from the spring housing. 
     However, the extension of the spring arm of the Chiang patent requires a comparatively wide spring and, therefore, a large installation depth. A very precise guidance of the lever is required, so that the connecting piece does not slip out of the groove. And with the application of force on the outer edge of the extension, there is the risk that the spring will flex toward the outer edge when the lever is actuated, and the actuating force will act unevenly on the spring. 
     The present invention was developed to provide an alternative spring-force clamping element, which requires less installation space, in particular, less installation depth, ensures proper clamping of an electric conductor in the spring-force clamping element, and allows for an easy opening of the clamping point. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is a primary object of the present invention to provide an improved compact spring-biased connector arrangement including a housing having a chamber containing a conductive bus bar, a clamping spring normally having an expanded clamping condition for biasing a conductor bare end toward electrical engagement with the bus bar, and a release lever pivotally connected with the housing for displacement from a normal closed clamping position toward an open position, whereby a lateral projection on the clamping lever operates the clamping spring toward a compressed open condition, thereby to permit removal of the conductor bare end from the housing chamber. 
     For this purpose, a spring-biased clamping arrangement is provided, including a spring housing having an insertion region for inserting an electrical conductor into the housing chamber, wherein a bus bar and a clamping spring are disposed in the spring housing in such a way that an electric conductor inserted through the insertion region into the spring housing may be clamped at a clamping point between the clamping spring and the bus bar, wherein the spring-force clamping element also includes a pivoting lever, which may be pivoted in a pivot direction about a pivot axis in order to open the clamping point, and which has a lateral operating projection, which presses the clamping spring in the pivot direction when opening the clamping point. A spring-biased clamping element of this type is used preferably as a printed circuit board clamp. 
     The spring-biased clamping element is distinguished by the fact that the lateral operating projection is disposed between the insertion region of the spring housing and the clamping spring. As a result, the lateral operating projection is disposed in the interior space of the spring housing adjacent the pivot axis of the release lever. Thus, the clamping spring need be designed no wider than is required for the conductor diameter of the electric conductor clamped by the spring-biased clamping element. As a result, the installation thickness of the spring-biased clamping element is adapted to the conductor diameter. 
     The insertion region of the housing is preferably funnel-shaped or cylindrical-shaped in design. The lateral operating projection is also preferably designed as a contact surface. However, other shapes of the insertion region and/or of the contact geometry are also possible. 
     It is preferable that the clamping spring includes a clamping leg that is pivotable about the pivot axis of the release lever. It also preferably includes a stationary support leg, which is braced against the spring housing and/or against a cage clamp when the clamping leg is pivoted. The clamping spring is particularly preferably designed as a leaf spring. It is even more preferably made of a spring steel. 
     In one preferred embodiment, the lateral operating projection is at least partially flat in engagement with the clamping leg, at least when the clamping point is opened. As a result, the force acting on the spring clamping leg is uniformly distributed on the latter in the region of the lateral operating projection. In addition, a lever guide is preferably provided on the spring housing, thereby to guide the lever during its pivotal opening operation. This prevents a twisting of the pivoting lever during opening and safely actuates the clamping spring leg. 
     The release lever preferably includes a mounting end and an operating end, with the lateral operating projection being disposed between the mounting and operating ends. It has preferably a generally U-shaped design, so that it may be properly and compactly integrated into the construction. 
     The release lever is preferably mounted at its pivot end, and on its end, is provided with an operating handle. Alternatively, it could be semi-circular in design. This makes an approximately linear actuation via the actuation angle possible. 
     In one particularly preferred embodiment, the lateral operating projection is disposed between the release lever ends, and preferably adjacent the mounting end. As a result, an open end of the clamping limb is freely movable when the clamping point is opened, thereby making it easy to remove the electrical conductor. 
     The pivoting lever is preferably mounted on the axial limb so as to be rotatable about the pivot axis. An actuating surface is also preferably provided on the actuating leg. In this way, the mechanical advantage is proved that lever travel is relatively long and the force required for actuating the clamping limb is relatively minimal. It is preferable that the actuating surface be designed for actuation with or without the use of an actuating tool. 
     The spring clamping limb preferably includes a first bend at the open end, as well as a second bend adjacent the lateral operating projection. As a result of the second bend, the clamping leg portion between the first bend and the second bend extends virtually transversely to the clamped electrical conductor, respectively. This allows for a low installation height. As a result of the first bend, an obtuse angle is also formed between the clamping limb and the electrical conductor, and the clamped electrical conductor cannot be removed from the spring-biased clamping element and is securely clamped. Moreover, as a result of the first bend, the open end of the clamping leg points in the conductor insertion direction. In this way, the electrical conductor may be inserted into and clamped undamaged in the spring housing. 
     Also preferably provided on the pivoting lever is a guide support projection, which in an assembled state of the spring-biased clamping element is disposed between the clamping le and the support leg of the clamping spring. Thus, the guide support projection is disposed in the interior chamber of the spring housing and does not increase the installation height. In addition, a guide groove for the clamping spring is formed between the operating later projection and the guide support projection. Moreover, when the clamping leg is pivoted back to its normal position, the release lever is also automatically pivoted back in the opposite direction toward its initial closed clamping position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       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: 
         FIG. 1  is an exploded perspective view of the spring-biased clamping connector of the present invention; 
         FIGS. 2 a -2 c    are front elevation views of the apparatus with certain parts removed, and  FIGS. 2 d -2 f    are corresponding front perspective views; 
         FIGS. 3 a  and 3 b    are rear perspective and rear elevation views, respectively of the invention with certain parts removed, and  FIGS. 3 c  and 3 d    are rear perspective and rear elevation views of the invention with certain parts removed; and 
         FIGS. 4 a -4 d    are detailed rear perspective views of the release lever arrangement. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring first more particularly to  FIG. 1  as an overview, the connector arrangement  1  of the present invention includes a housing  2  formed of a non-conductive synthetic plastic material, and includes a vertical bottom wall and side walls cooperating to define a chamber  20  in which are mounted a conductive cage member  3  and a clamping spring  4 . As shown in  FIGS. 2 c  and 2 f   , the front of the chamber is partially closed by a release lever  5  that is pivotally connected with the housing by a pivot shaft  60 . An access opening  21  is provided in the side walls of the housing to permit the bare end of an insulated conductor  8  to be inserted into and removed from the housing chamber  20 . The conductor  8  can be a single-wire conductor, or a braided wire conductor. In the case of a braided wire conductor, a protective funnel-shaped conductive support sleeve  7  is provided for introducing the bare conductor end into the housing chamber  20 . 
     The conductive cage member  3 , has a generally U-shaped configuration including a vertical rear wall  35  adjacent the chamber bottom wall, and a pair of vertical side walls  32  and  33 . The side wall  32  is provided with a lower support ledge  321 , and the side wall  33 , which serves as a bus bar, is provided with a contact rib  34 . The cage  3  includes a lower contact portion  31  having a horizontal wall that is seated on a horizontal cross-support  22  on the housing  2 , and a plurality of pin contacts  311  that extend downwardly and outwardly from the housing. 
     As shown in  FIGS. 2 a -2 e   , the clamping spring  4 , which is formed from spring steel or the like, is a compression spring having a generally inverted V-shaped configuration defining a clamping leg  41  joined to a support leg  42  by a connecting portion  46 . The connecting portion  46  is supported by the enlarged portion  26  of a horizontal pivot shaft  60  the rear end of which is connected with the bottom wall of the housing chamber  20 . As best shown in  FIGS. 2 a  and 2 b   , the spring support leg  42  abuts the support ledge  321  on the cage side wall  32 . The spring clamping leg  41  contains a first bend  45  that defines leg portions  41   a  and  41   b  that are arranged at an obtuse angle, and a second bend  43  that defines a terminal tab  44  at the end of the clamping leg portion  41   b . The terminal tab portion  44  of the spring clamping leg  41  normally engages the conductor support sleeve  7  and biases the same toward conductive engagement with the bus bar  33 . 
     The release lever  5  has a generally U-shaped configuration, and includes a mounting leg  56  and an operating leg  57  joined by a connecting portion  58 . The mounting leg  56  contains a pivot opening  51  by means of which the release lever is pivotally supported on the pivot shat  60  for pivotal movement about the fixed pivot axis  6 . The mounting arm  56  carries the lateral operating projection  52  that engages the clamping leg portion  41   a , as best shown in  FIGS. 4 a -4 c   . The operating leg  57  carries the handle portion  53  which contains an operating recess  54  for receiving an operating tool, such as the tip of a screwdriver. 
     The clamping spring  4  is normally in the unstressed expanded clamping condition shown in  FIGS. 1, 3   a  and  4   a , whereupon the release lever  5  is in its initial closed clamping position with the spring clamping leg biasing the conductor sleeve  7  toward conductive engagement with the bus bar  33 . The conductor  8  is thus connected with the pin terminals  311  for soldered connection with the desired distribution conductors (not shown). To open the connector for insertion and removal of the conductor sleeve  7  and the conductor  8 , the user applies—either manually or by an operating tool—a downward force  59  ( FIG. 4 a   ) to the handle portion  53 , thereby to pivot the release lever  5  in the direction  61  of  FIG. 1 . The lateral operating projection  52  applies pressure to the spring clamping leg portion  41   a  to compress the clamping spring and thereby displace the tab extremity  44  away from the conductor support sleeve  7 , thereby to permit removal of the sleeve and the conductor from the housing  2 . Upon removal of the opening force  59 , the clamping spring expands to it normal unstressed condition, and the clamping leg  41  pivotally returns the release lever to its initial closed position. 
     Referring again to  FIG. 1 , the cage clamp  3  is accessible through an insertion region  21  provided in the spring housing  2 . The spring housing  2  is preferably made of an electrically insulating material, preferably a synthetic plastic material, and may be designed as part of a primary housing, for example, of a terminal block. The cage clamp  3  is preferably made of an electrically well-insulating metal, preferably of a copper-containing metal or of copper. 
     Provided adjacent to the insertion region  21  is the pivot shaft  60  having an enlarged profile portion  26  supporting the clamping spring  4 . Here, the V-shaped clamping spring  4  is designed as a leaf spring. It includes a clamping leg  41  and a support leg  42 , which are connected to one another by an approximately semicircular connecting portion  46 . The clamping spring  4  is preferably manufactured from spring steel. 
     The clamping spring  4  is guided around the holding contour  26  in the region of the connecting portion  46 . The pivot shaft  60 , designed in approximately the center of the cross limb  46 , extends concentrically about the pivot axis  6  and forms a pivot shaft. In this way, the spring clamping leg  41  is pivotable about the pivot axis  6 . 
     The preferably U-shaped cage clamp  3  includes a bus bar  33 , which is disposed transversely to a rear wall  35  of the cage clamp  3 . A side wall  32 , on which a support piece  321  is provided, is formed opposite the bus bar  33  transversely to the rear wall  35 . 
     During a pivoting movement of the spring clamping leg  41  in a pivot direction  61  about the pivot axis  6 , the support leg  42  of the clamping spring is braced against the support piece  321 . In this process, the clamping leg  41  is pivoted in the pivot direction  61  against the restoring force of the clamping spring  4 . 
     Also provided on the cage member  3  is an integral connecting piece  31  on which, in this case, four connector pins  311  are provided for connection with electric conductors (not shown). The connector pins  311  shown here are designed as solder pins. Other connectors are also possible, however, for example, a contact spring or a contact pin or differently designed connectors, which allow for soldering, clamping, inserting or the like. The configuration of the connecting piece  31 , of the connector pins  311  or other connectors is selected in accordance with the existing installation space. 
     The cage member  3  may be inserted into the interior space  20  of the spring-force clamping element  1  above a cross piece  22  of the spring housing  2 . When the cage clamp  3  is inserted, the connector pins  311  are guided outwardly, so that the interior space  20  remains free for the clamping spring  4  and an electric conductor support sleeve  7  (see  FIG. 2 ) inserted into the spring housing  2 . Furthermore, the connector pins  311  are accessible from the outside as a result. 
     Once the spring-biased connector  1  is assembled, the electric conductor support sleeve  7  may be inserted between the spring clamping leg  41  and the bus bar  33 . In the assembled position M (see  FIGS. 2, 3 ), the electric conductor is forced by the clamping leg  41  opposite the pivot direction  61  against the bus bar  33  at a clamping point  40 , indicated here by an arrow. The electric conductor support sleeve  7  shown here is, for example, a sleeve, in which a stranded or braided conductor is normally inserted. The spring-biasing element may, however, also be used without a sleeve for a stranded conductor and for a solid wire conductor. 
     A release lever  5  is provided, in order to release the electric conductor  7  from the spring-biased connector and to remove the conductor in a direction opposite to the conductor insertion direction. With the release lever  5 , it is possible not only to release the electric conductor  7  from the spring-force clamping element  1 . Rather, the pivoting lever  5  is also provided for opening the clamping point  40 . It therefore allows the clamping point  40  to be opened before an electric conductor  8 , in particular, a thin-wire electric conductor  8 , is to be clamped in the spring-biased clamping arrangement  1 . With the clamping point  40  opened, it is very easy to insert the electric conductor sleeve  7 —or the conductor  8  directly—into the clamping point  40 . 
     The base portion  58  of the release lever  5  in this case is approximately U-shaped in design.  FIGS. 4 b  and  d    illustrate that the U-shaped cage  3  of the pivoting lever are advantageously situated opposite one another, such that they form a kind of closed contour, which encompasses an inserted conductor, wherein the release lever  5  remains pivotable. At its mounting end  56 , the release lever is disposed on the pivot shaft  60  and is mounted so as to be rotatable about the pivot axis  6 . For this purpose, a through-hole  51  is provided, which extends concentrically about the pivot axis  6 , and which is mounted so as to be rotatable on the pivot shaft  60 . Differently shaped release levers  5 , for example, a semicircular or a V-shaped release lever  5 , are also conceivable. 
     In addition, the operating leg  57  of the release lever  5  also includes an actuating handle portion  53 . The pivoting lever  5  may be actuated manually at the actuating handle  53 . In addition, a recess  54  for an actuating tool (not shown) is provided so that there, too, the release lever  5  may be actuated using the actuating tool, for example, a screw driver. Instead of an actuating handle  53 , however, a more compact actuating surface  53  is preferred, which allows only one actuation using an actuating tool. 
     To be able to actuate the clamping leg  41  with the pivoting lever  5 , so that the clamping point  40  is opened and the clamped electric conductor  7  may be inserted into the spring-biased arrangement  1  or may be removed again from the spring-force clamping element  1 , a lateral operating projection contact geometry  52  is provided between the mounting leg  56  and the operating leg  57 . In the assembled spring-biased clamping element  1 , the lateral operating projection  52  is disposed between the clamping limb  41  and the insertion region  21 . As a result, it is disposed in the interior space  20  of the spring-biased connector arrangement  1  and does not increase the installation depth of the arrangement. 
     When the release lever  5  is pivoted about the pivot axis  6  in the pivot direction  61 , the lateral operating projection  52  presses on the clamping limb  41 . As a result, the clamping leg  41  is also pivoted about the pivot axis  6  in the pivot direction  61 . 
     The lateral operating projection  52  has a flat design and fits at least partially flat against the clamping leg  41 , at least when opening the clamping point  40 , i.e., when pivoting the release lever  5  in the pivot direction  61 . As a result, the force is evenly distributed on the clamping leg  41  in the region of the lateral operating projection  52 . Moreover, it does not break as a result when actuating the pivoting lever. 
     Due to the restoring force of the clamping spring  4 , the clamping leg  41  is automatically pivoted back opposite the pivot direction  61  when the electric conductor sleeve  7  is removed from the spring-biased connector  1 , and the release lever  5  is no longer acted upon by any actuating force. The clamping leg  41  at this point fits partially against the lateral operating projection  52  and presses on the projection  52  opposite the pivot direction  61 , so that the release lever  5  is pivoted back by the clamping spring  4 . 
     Also provided on the release lever  5  is a guide projection contour  55  ( FIG. 4 a   ), which in the assembled state of the spring-biased connector  1  is disposed between the clamping leg  41  and the support leg  42 . As a result, a guide groove  551  (see  FIG. 2 b   ) is formed between the lateral operating projection  52  and the guide projection  55 , in which the clamping leg  41  is safely guided when pivoted. 
     A lever guide arrangement  23  is provided on the housing  2 , so that the installation depth of the spring-biased connector  1  is not increased unnecessarily by the release lever  5 . During pivoting, the release lever  5  is guided along the lever guide  23 . The lever guide arrangement  23  also prevents the release lever  5  from freely pivoting when the electric conductor sleeve  7  is connected. 
     In order to limit the installation height of the spring-biased connector  1 , and to create a good holding force on the inserted electric conductor sleeve  7 , the clamping leg  41  includes a first bend  43  and a second bend  45 . 
     The first bend  43  is provided at an open end  44  of the clamping limb  41 . The second bend  45  is provided in the region of the contact geometry  52 . As a result of the second bend  45 , the clamping limb  41  between the first bend  43  and the second bend  45  extends virtually transversely to the clamped electric conductor  7 , respectively, the conductor insertion direction  8 . The installation height is minimal as a result. As a result of the first bend  43 , an obtuse angle is formed between the clamping limb  41  and the electric conductor  7 , and securely clamps the conductor in the spring-force clamping element  1 . The direction of the installation depth  81 , the installation width  82  and the installation height  83  are shown in  FIGS. 2 and 3 . 
     To open the clamping point and to release an electric conductor  7  clamped in the spring-force clamping element  1 , requires an actuating force on the actuating handle  53  or the recess  54  at the open end  59  of the actuating leg  57  of the pivoting lever  5 , which acts in the conductor insertion direction. 
       FIGS. 4 ( a ) and ( c )  show a base position G of the clamping spring  4 , in which no electric conductor  7  is inserted in the spring housing  2 . In this base position, the clamping leg  41  extends approximately transversely to the conductor insertion direction. 
       FIG. 4 ( b )  shows an assembly position M of the clamping spring  4 , in which an electric conductor sleeve  7  is inserted into the spring housing  2  and clamped in said housing between the open end  44  of the clamping leg  41  and the bus bar  33 . The electrically conductive end of the sleeve  7  is identified here by the reference numeral  71 . 
       FIG. 4( d )  shows an open position O of the clamping spring  4 , in which the clamping leg  41  and the release lever  5  are pivoted as far as possible in the pivot direction  61 . This open position O is possible, only if the actuating force acts on the release lever  5  in the conductor insertion direction. The actuating force is shown here by an arrow  9 . However, it is also preferable to provide catch means (not shown) in the spring-force clamping element  1 , so that the release lever  5  is locked in place in the open position O. 
     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.