Patent Publication Number: US-9413082-B2

Title: Spring force terminal connection and electric device therewith

Description:
This application is a national phase of International Application No. PCT/EP2013/073135 filed Jun. 6, 2013. 
     The invention relates to a spring force terminal connection comprising:
         a busbar,   a clamping spring, which has a resting section which is supported on the busbar, a spring bend, which adjoins the resting section, an actuating section, which adjoins the spring bend and is opposite the resting section, and a clamping section, which adjoins the actuating section and extends from the actuating section in the direction of the busbar,
 
wherein the clamping section has a conductor leadthrough opening, and wherein the busbar is passed through the conductor leadthrough opening, and a clamping point for a conductor to be connected is provided between the busbar and a transverse web limiting the conductor leadthrough opening,
   and an actuating element, which is mounted movably for acting on the actuating section in such a way that the transverse web, which limits the conductor leadthrough opening and forms a clamping point, is movable away from the busbar in the case of a movement of the actuating element, for example by pivoting or a linear movement, into an open position.       

     The invention furthermore relates to an electrical device comprising an insulating housing and comprising at least one such spring force terminal connection in the insulating housing. 
     Spring force connection terminals are known in a variety of forms, for example from conductor connection terminals, terminal boxes, terminal blocks or installed in electrical devices, such as automation devices for industrial control or building automation, for example. 
     EP 1 213 791 B1 discloses an electrical connector comprising a cage strain spring comprising a self-supporting actuating lever. This actuating lever is mounted rotatably on a bent-back busbar section. 
     DE 10 2008 060 282 A1 discloses a spring terminal which can be actuated without the use of a tool for an electrical conductor, in which an actuating lever is suspended in a notch in the resting limb of a cage strain spring and is guided laterally past the cage strain spring with at least one side limb. 
     DE 10 2008 052 626 A1 describes a connection terminal comprising a bow engaging around a clamping spring on both sides, on which bow an actuating lever is articulated. 
     EP 2 001 086 B1 discloses a screwless connection terminal comprising a cage strain spring, in which an actuating lever is suspended in a bearing bend of a busbar behind the spring bend of the cage strain spring. The actuating lever engages around the busbar on both sides and rests on the actuating section of the cage strain spring. 
     Against this background, the object of the present invention consists in providing an improved spring force terminal connection comprising a self-supporting and compact actuation arrangement. 
     The object is achieved by the spring force terminal connection having the features of claim  1  and by the electrical device having the features of claim  7 . 
     Advantageous embodiments are described in the dependent claims. 
     It is proposed for a spring force terminal connection comprising a cage strain spring that a bearing arm extends out of the direction of the busbar through a slot in the clamping section and/or in the actuating section and interacts with the actuating element for movably mounting the actuating element, wherein that section of the bearing arm which extends through the slot is arranged in a region between the side edges of the clamping spring and supports the actuating element. 
     It is therefore proposed not to guide a bearing arm laterally past the clamping spring, as has previously been conventional, but to pass the bearing arm through a slot in the clamping section and/or in the actuating section of the cage strain spring. In this case, the actuating element adjoins the bearing arm and, when actuated, rests on the actuating section of the clamping spring in order to exert an actuation force. Thus, a very compact and self-supporting actuating arrangement which has a closed force flow during pivoting of the actuating element is realized. The lever actuation forces in this case do not act on the housing in the steady state, and the actuation by the actuating element is largely independent of the insulating housing of the connection terminal. The splitting of the connection terminal in this case remains unaffected, so that the proposed solution enables a connection terminal with a narrow design, even when taking into consideration the required air gaps and leakage paths. 
     The width of the spring force terminal connection in the direction of division, i.e. transversely to the direction of extent of the busbar and the clamping section of the clamping spring, is in any case not enlarged by the actuating element. 
     The cage strain spring with the bearing arm arranged thereon and passed therethrough and comprising the actuating element can also be treated separately as one assembly and built into a device, which already provides a busbar. 
     The provision of a slot in the clamping section and/or in the actuating section for passing through the bearing arm has no disadvantageous effects on the strain distribution in the cage strain spring. This is determined critically by the spring bend, which remains unaffected. 
     It is particularly advantageous if the bearing arm is arranged centrally in the direction of the width of the clamping spring, i.e. the bearing arm is guided centrally transversely with respect to the direction of extent of the busbar and transversely with respect to the direction of extent of the clamping section and the resting section of the cage strain spring. The bearing arm is thus in the center, when viewed from the opposite side edges of the cage strain spring, and is arranged there preferably in the region of the clamping section. However, it is essential that the bearing arm is not guided laterally past the clamping spring, but is arranged at least partially in the space surrounded by the clamping spring. 
     In a preferred embodiment, the bearing arm is formed as an extension of the resting section integrally with the clamping spring. For this purpose, a spring steel sheet section is cut or punched out of the resting section and bent back in the direction of the actuating section away from the resting section and the busbar arranged therein. 
     The actuating element can then be mounted pivotably on the free end of the bearing arm. For this purpose, it is advantageous if the bearing arm has a pivot bearing at its end remote from the busbar and the actuating element is mounted pivotably in or on the pivot bearing. 
     In an alternative embodiment, however, it can also be mounted linearly movably on the exposed bearing arm. If appropriate, a further flap of material bent out of the clamping spring can be used for this purpose for further guidance. 
     However, it is also conceivable for a separate bearing arm to be arranged between the resting section of the clamping spring and the busbar. This bearing arm can be formed from a plastic material, for example. The bearing arm can be fixedly connected integrally to the actuating element and mounted pivotably or displaceably in the margin between the resting section of the clamping spring and the busbar. 
     However, it is particularly advantageous if the bearing arm has a pivot bearing at its end remote from the busbar, and the actuating element is mounted pivotably in this pivot bearing. The bearing arm and the actuating element can in this case be two separate parts, for example consisting of a plastic material. However, it is also conceivable for the bearing arm and the actuating element to be formed as an integral plastic part with a film hinge. 
     In an alternative embodiment, the bearing arm can be mounted displaceably linearly relative to the busbar on the busbar in the region of the point at which the resting limb of the clamping spring rests. The bearing arm is in this case preferably formed integrally with the actuating element. In this way, actuation of the cage strain spring can be realized by opening the clamping point by means of a linearly displaceable thruster element, which is passed through the slot in the clamping section and/or the actuating section. In this variant too, a very compact and self-supporting actuating element is realized, in which a relatively large actuating force is not transmitted to the insulating housing. 
     A particularly advantageous, self-supporting variant with a linearly displaceable actuating element is achieved if the bearing arm is fixed on the busbar, and the actuating element is arranged linearly movably relative to the busbar on the bearing arm. 
    
    
     
       The invention will be explained by way of example in more detail below with reference to the attached drawings, in which: 
         FIG. 1  shows a perspective view of a first embodiment of a spring force terminal element comprising a busbar, a cage strain spring, and an actuating element mounted pivotably on a bearing arm formed integrally with the busbar; 
         FIG. 2  shows a side view of the spring force terminal connection shown in  FIG. 1 ; 
         FIG. 3  shows a plan view of the spring force terminal connection shown in  FIGS. 1 and 2 ; 
         FIG. 4  shows a sectional side view in the section B-B of the spring force terminal connection shown in  FIGS. 1 to 3 ; 
         FIG. 5  shows a side view of a clamping spring for the first embodiment of the spring force terminal connection shown in  FIGS. 1 to 4 ; 
         FIG. 6  shows a perspective view of the cage strain spring shown in  FIG. 5 ; 
         FIG. 7  shows a perspective view of a second embodiment of a spring force terminal connection having a separate bearing arm arranged between the resting section and the busbars and an actuating element articulated on said bearing arm in a front side view; 
         FIG. 8  shows a perspective view of the spring force terminal connection shown in  FIG. 7  in a rear side view; 
         FIG. 9  shows a side view of the second embodiment of the spring force terminal connection shown in  FIGS. 7 and 8 ; 
         FIG. 10  shows a plan view of the spring force terminal connection shown in  FIGS. 7 to 9 ; 
         FIG. 11  shows a sectional side view of the second embodiment of the spring force terminal connection in the section F-F; 
         FIG. 12  shows a perspective view of the second embodiment of the spring force terminal connection having a raised actuating element in the open position; 
         FIG. 13  shows a perspective rear side view of the open spring force terminal connection shown in  FIG. 12 ; 
         FIG. 14  shows a side view of the open spring force terminal connection shown in  FIGS. 12 and 13 ; 
         FIG. 15  shows a perspective view of the cage strain spring for the second embodiment of the spring force terminal connection shown in  FIGS. 7 to 14 ; 
         FIG. 16  shows a perspective rear side view of the spring force terminal connection shown in  FIG. 15 ; 
         FIG. 17  shows a perspective view of the cage strain spring shown in  FIGS. 15 and 16  from above; 
         FIG. 18  shows a plan view of the cage strain spring shown in  FIGS. 15 to 17 ; 
         FIG. 19  shows a side view of the cage strain spring shown in  FIGS. 15 to 18 ; 
         FIG. 20  shows a perspective view of an electrical device comprising an insulating housing and spring force terminal connections installed therein from the second embodiment; 
         FIG. 21  shows a plan view of the electrical device shown in  FIG. 20 ; 
         FIG. 22  shows a sectional side view through the electrical device shown in  FIGS. 20 and 21  in the section F-F; 
         FIG. 23  shows a perspective view of a third embodiment of a spring force terminal connection having a linearly movable actuating element from the rear side; 
         FIG. 24  shows a perspective view of the third embodiment of a spring force terminal connection in a view from the front; 
         FIG. 25  shows a plan view of two cage strain springs arranged next to one another in the open and closed state of the third embodiment of the spring force terminal connection shown in  FIGS. 23 and 24 ; 
         FIG. 26  shows a side view of the third embodiment of the spring force terminal connection in the section F-F of the open cage strain spring; 
         FIG. 27  shows a sectional side view of the third embodiment of the spring force terminal connection in the section G-G of the closed cage strain spring. 
     
    
    
       FIG. 1  shows a perspective view of a first embodiment of a spring force terminal element  1 . The spring force terminal element  1  has a busbar  2 , whose free end is bent away upwards in a manner known per se so as to form a clamping edge  3  which curves downwards. The busbar  2  is narrower in the region of the free end. There, a clamping spring  4  is suspended in the busbar  2 . The clamping spring  4  is in the form of a cage strain spring known per se. A cage strain spring is a loop-like structure consisting of a spring-elastic material. The clamping spring  4  has a resting section  5 , which is supported on the busbar  2 . In the exemplary embodiment illustrated, the resting section rests at least partially on the busbar  2 . A spring bend  6  adjoins the resting section  5 . The spring bend  6  merges with an actuating section  7 , which is opposite the resting section  5 . It becomes clear that the resting section  5  and the actuating section  7 , together with the spring bend  6 , are V-shaped in cross section. A clamping section  8  is bent back from the actuating section  7  and extends downwards from the actuating section  7  in the direction of the resting section  5  and the busbar  2 . 
     The clamping section  8  has a conductor leadthrough opening  9  in the central region, said conductor leadthrough opening being limited at the lower free end of the clamping section  8  by a transverse web  10 . A conductor introduced beneath the busbar  2  is then guided through the conductor leadthrough opening  9  when the transverse web  10  is moved downwards by the busbar  2  and is clamped to the busbar  2  by the transverse web  10 . The conductor is preferably clamped to the exposed clamping edge  3  of the busbar  2 . 
     The clamping section  8 , by virtue of the shaped conductor leadthrough opening  9 , has two lateral marginal webs  11 , which are connected to one another in the lower region by the transverse web  10 . 
     The free space created in the clamping section  8  by the conductor leadthrough opening  9  is used for a bearing arm  12 , which extends out of the direction of the busbar  2  through the slot formed with the aid of the conductor leadthrough opening  9  in the exemplary embodiment illustrated in the clamping section  8  and preferably ends above the transition between the actuating section  7  and the clamping section  8 . It becomes clear that a separate actuating element  13  in the form of a lever arm is mounted pivotably on the bearing arm  12 . For this purpose, the free end of the bearing arm  12  is bent back and a bearing spindle (not shown) is suspended in the bent-back end  14  of the bearing arm  12 . 
     The actuating element  13  has two actuating fingers  15  which are spaced apart from one another and between which the bearing arm  12  is accommodated. The actuating fingers  15  merge with a top part  16  which protrudes forwards and which connects the actuating fingers  15  to one another. The top part  16  and the actuating fingers are formed integrally from a plastic material together with the bearing spindle (not shown). 
     The actuating fingers  15  have a curved shape matched to the actuating section  7  in the direction of the clamping spring  4  adjoining the actuating section  7  in such a way that the free ends of the actuating fingers  15  migrate downwards in the direction of the busbar  2  and the resting section  5  when the top part  16  is pivoted upwards and in the process press the actuating section  7  in the direction of the resting section  5 . In this case, the transverse web  10  of the clamping section  8  migrates towards the opening in the clamping point, formed by the transverse web  10  and the busbar  2 , downwards away from the busbar  2 . 
       FIG. 2  shows the spring force terminal connection  1  shown in  FIG. 1  in a side view. It is shown that the bearing arm  12  is formed integrally with the clamping spring  4 . It is punched or cut free from the sheet-metal part of the resting section  5  and is bent back in the region of the free end of the resting section  5  out of said resting section upwards opposite to the direction of extent of the clamping section  8 . 
     It is shown that the bearing arm  12  is not guided laterally past the clamping spring  4 , but is arranged in the region between the side edges of the clamping spring  4 . In the exemplary embodiment illustrated, the bearing arm  12  is passed through the conductor leadthrough opening  9  of the clamping section  8  between the marginal webs  11  of the clamping section  8 . 
       FIG. 3  shows a plan view of the spring force terminal connection shown in  FIGS. 1 and 2 . It is shown that the actuating element  13  has a top part  16  with actuating fingers  15  integrally adjoining said top part. The actuating fingers  15  are thus spaced so far apart from one another that they accommodate the bearing arm  12  with the bent-back free end  14  between them in order to mount the actuating element  13  pivotably on the bearing arm  12 . 
     This becomes even clearer from the sectional side view in the section B-B in  FIG. 4 . Here, it can be seen that a bearing spindle  17  extends in the width direction (i.e. in the viewing direction) of the spring force terminal connection  1  transversely to the bearing arm  12 . It can be seen that the bearing spindle  17  is cylindrical and that free end  14  of the bearing arm  12  which is bent back by more than 180 degrees is snapped onto the bearing spindle  17 . Thus, the actuating element  13  is mounted pivotably on the bearing arm  12 . By virtue of the free end  14  being bent through more than 180 degrees, the bearing spindle  17  is fixedly surrounded by the free end  14  and cannot easily expand downwards. 
     It is furthermore shown that the top part  16  has an actuating opening  18  which extends from the right to the left in the rest position illustrated in the conductor plug-in direction, i.e. in the illustrated sectional side view. The actuating opening  18  is provided for receiving the free end of an actuating tool, such as a screwdriver, for example, with which the lever arm is extended upwards for pivoting the actuating element  13  and the actuation is facilitated. The actuating opening  18  is therefore formed so as to taper conically towards the bottom in the exemplary embodiment illustrated. 
       FIG. 5  shows a side view of the clamping spring  4 , as is used in the previously described exemplary embodiment of the spring force terminal connection  1 . In contrast to the cage strain springs known per se, a bearing arm  12  is bent out of the resting section  5  in the central region adjoining the free end of the resting section  5 . The bearing arm  12  extends from the resting section  5  in the opposite direction to the direction of extent of the clamping section  8  and ends above the transition between the actuating section  7  and the clamping section  8  in a bent-back free end  14 . Then, a suitably formed actuating element is mounted on the bearing arm  12  with the bent-back free end  14 . In this way, a self-supporting, lever-actuated spring force terminal connection comprising a cage strain spring is realized which is very compact, saves on materials and has a simple design. 
       FIG. 6  shows a perspective view of the clamping spring  4  shown in  FIG. 5 . It can be seen more clearly from this figure that the clamping section  8  has a conductor leadthrough opening  9 , whilst preserving marginal webs  11 , said conductor leadthrough opening extending as far as a bend at the transition to the actuating section  7 . A cutout  20  which is narrower than the conductor leadthrough opening  9  is provided in the top part of the bend  19  at the transition between the clamping section  8  and the actuating section  7 , with it being possible for the bearing arm  12  to dip into said cutout when the actuating section  7  is pressed downwards in the direction of the resting section  5 . 
     The free end of the resting section  5  ends in narrower protruding lugs  21 , with the marginal webs  11  of the clamping section  8  being guided past said lugs. 
       FIG. 7  shows a perspective view of a second embodiment of a spring force terminal connection  1 . In turn, said spring force terminal connection consists of a clamping spring  4  in the form of a cage strain spring, a busbar  2  and an actuating element  13 . In this embodiment, the bearing arm  22  is not formed integrally with the clamping spring  4 , as in the first embodiment, but is formed as a separate part. The bearing arm  22  is preferably a plastic part. It has a base  23  positioned between the busbar  2  and the resting section  5  of the clamping spring. An arm section  24  protruding vertically on the base  23  extends perpendicularly upwards from the base  23 . The arm section  24  is arranged in the free space formed by the marginal webs  11  of the clamping section  8  and thus substantially in the space spanned by the cage strain spring. The actuating element  13  is mounted pivotably at the free end of the arm section  24 , which is opposite the base  23 . For this purpose, a bearing spindle  17  is passed through a bearing opening  25  in the actuating fingers  15  of the actuating element  13 , which is accommodated in a corresponding bearing opening (not shown) in the arm section  24 . In this way, the actuating element  13  is held pivotably on the arm section  24  of the bearing arm  22 . 
       FIG. 8  shows the second embodiment of the spring force terminal connection  1  from  FIG. 7  in the perspective rear side view. It can be seen that the actuating element  13 , as in the case of the first embodiment, has actuating fingers  15  which are arranged spaced apart from one another and which rest with their curved lower side on the actuating section  7  of the clamping spring  4 . 
     It can also clearly be seen that the bearing arm  22  is pushed with its base  23  through the conductor leadthrough opening  9  in the clamping section  8  of the clamping spring  4  in order to be positioned between the busbar  2  and the resting section  5 . Thus, the resting section  5  is supported indirectly on the busbar  2  and rests directly on the base  23  of the bearing arm  22 . 
       FIG. 9  shows a side view of the spring force terminal connection  1  shown in  FIGS. 7 and 8 . It can be seen here that the base  23 , at its right-hand free end adjoined by the arm section  24  of the bearing arm  22 , has a downwardly pointing protrusion  25 , which dips into the curvature provided so as to form a clamping edge  3  at the free end of the busbar  2 . In this way, the bearing arm  22  is fixed in position on the busbar  2 . 
       FIG. 10  shows a plan view of the spring force terminal connection  1  shown in  FIGS. 7 to 9 . In contrast to the first embodiment, the actuating element  13  is completely closed on the upper side so that the actuating fingers  15  are connected to one another not only by the top part  16 , but also on the upper side. 
       FIG. 11  shows a sectional side view of the spring force terminal connection  1  of the second embodiment shown in  FIGS. 7 to 10 . It can be seen from  FIG. 11  that the top part  16  of the actuating element  13  has a depression  18 , which tapers conically towards the bottom, on the front end face for receiving an actuating element. To this extent, reference can be made to the statements in respect of the first embodiment. 
     It can also be seen that the arm section  24  of the bearing arm  22  has a bearing opening  26  at the upper free end, which is opposite the base  23 , with the bearing spindle  17  being plugged through said bearing opening  26 . 
       FIG. 12  shows a perspective view of the second embodiment of a spring force terminal connection  1  from the front in the open position. In this case, the actuating element  13  is pivoted upwards to approximately 90 degrees with the top part  16 , in contrast to the previously illustrated rest position. The actuating fingers  15  in this case migrate with their free ends relative to the bearing spindle  17  and the top part  16  downwards in the direction of the busbar  2  so that the actuating section  7  is pushed down towards the resting limb  5  and the busbar  2 . As a result, the clamping point is opened. The clamping point is formed by the transverse web  10 , which delimits the conductor leadthrough opening  9  at the bottom, and the clamping edge  3  on the busbar  2 . An electrical conductor can now be plugged forwards, in the viewing direction, i.e. from right to left, through the conductor leadthrough opening  9  in the clamping section  8  of the clamping spring  4  in order to be clamped electrically conductively to the busbar  2  once the actuating element  13  has been pivoted into the previously illustrated rest position between the transverse web  10  and the clamping edge  3  owing to the spring force of the clamping spring  4 . 
     It can be seen that the separate bearing arm  22  is accommodated in the slot in the clamping section and partially also in the actuating section of the clamping spring  4  and extends through the slot, which is formed by the conductor leadthrough opening  9  and the cutout  20 , in the clamping spring  4 . 
     This becomes even clearer from the perspective rear side view in  FIG. 13 . It can be seen here that the arm section  24  is passed from the base  23  additionally through a cutout  28  in the resting section  5 . These cutouts in the clamping spring  4  are arranged, when viewed in the width direction, between the side edges of the clamping spring  4  and preferably centrally. The bearing arm  22  is therefore arranged on half the width of the busbar  2  and the clamping spring  4 . 
       FIG. 14  shows a side view of the second embodiment of the spring force terminal connection  1  in the open position. In this open position illustrated, the actuating element  13  is preferably self-locked. This is achieved by virtue of the fact that the actuating section  7  of the clamping spring  4  now exerts a force on the actuating element  13 , which is directed approximately towards the bearing spindle  17  in this open position. Thus, a tilting moment which would cause the actuating element  13  to pivot back into the rest position is avoided. 
     The curved shape of the actuating fingers  15  is therefore matched to the kinematics of the actuating element  13  and the clamping spring  4  in such a way that best-possible force and moment distribution is ensured in each angular position of the actuating element  13 . 
       FIG. 15  shows a perspective view of the clamping spring  4  of the second embodiment of the spring force terminal connection  1  in the installed position. In comparison with the clamping spring  4  for the first embodiment, the cutout  20  is longer and extends further into the actuating section  7 . This is caused by virtue of the fact that the arm section  24  of the bearing arm spans a greater, triangular area than the bearing arm  12  of the first embodiment, which is in the form of a flat sheet-metal element. 
     It can furthermore be seen that a cutout  28  is provided in the resting section  5 , through which cutout the arm section  24  of the bearing arm  22  is passed. 
     This becomes clearer from the perspective illustration in  FIGS. 16 and 17 , which show the clamping spring  4  in the perspective rear side view and the perspective view at an angle from above. The cutout  20  forms, together with the conductor insertion opening  9 , a first slot, and the cutout  28  forms a second slot, through which the bearing arm  22  can extend from the lower side of the resting section  5  upwards in the direction of the transition between the actuating section  7  and the clamping section  8 . These cutouts  20 , and the conductor leadthrough opening  9  are delimited on both sides by the side edges of the clamping spring  4  and in particular by the marginal webs  11  of the actuating section  8  or are located within the space formed by the marginal webs  11  and the side edges of the clamping spring  4 . 
       FIG. 18  shows a plan view of the clamping spring  4  shown in  FIGS. 15 to 17 . From this figure it is clear that the cutout  20 , the conductor leadthrough opening  9  and the cutout  28  are arranged in the bearing limb  5  centrally, when viewed in the width direction (from the bottom to the top in the illustration). 
       FIG. 19  shows a sectional side view in the section F-F of the clamping spring  4  from  FIG. 18 . It can be seen from the hatched sections that spring sheet-metal material is provided there in the section F-F for the transverse web  10 , the actuating section  7 , the spring bend  6  and the resting section  5 . In addition, it becomes clear that a slot is created by the cutout  20  and the conductor leadthrough opening  9  at the transition between the actuating section  7  and the clamping section  8  in the central section F-F, which slot is delimited first at the free end of the clamping section  8  by the transverse web  10 . The resting section  5  likewise has a slot which runs as far as the free end and is formed by the cutout  28 . 
       FIG. 20  shows a perspective view of an electrical device, in which two spring force terminal connections of the type mentioned at the outset are built into an insulating housing  29 . In the embodiment illustrated, the second embodiment of the spring force terminal connection  1  has been used. Equally, however, the spring force terminal connection of the first exemplary embodiment can also be used. 
     The spring force terminal connections  1  are self-supporting and can be installed together with the actuating element  13 , the busbar  2  and the clamping spring  4  as well as the bearing arm  22 , in a preassembled state, in the insulating housing. Conductor insertion openings  31  are provided in the front end side wall  30  of the insulating housing  29 , said conductor insertion openings opening out into the space directly beneath the busbar  2  in order to clamp an electrical conductor on the busbar  2  by means of the clamping spring  4 . 
     The top part  16  of the actuating elements  13  protrudes in each case out of the housing through a corresponding cutout and is preferably, on the upper side, aligned flush with the upper side  32  of the insulating housing in the rest position (right-hand spring force terminal connection). Thus, a closed, block-like connection terminal is provided. 
     This becomes clearer from the plan view of the electrical device from  FIG. 20  in  FIG. 21 . 
       FIG. 22  shows a sectional side view in the section F-F through the spring force terminal connection  1  which is in the open position. In this case, it can be seen that the spring force terminal connection  1  together with the busbar  2 , the clamping spring  4 , the bearing arm  22  and the actuating element  13  as a whole is fixed in the insulating housing  29 . It can be seen that the conductor insertion openings  31  in the end side wall  30  of the insulating housing  29  open out in the clamping space  32  beneath the busbar  2 . The insulating housing  29  is formed in several parts and can be latched to one another by means of a latching apparatus  33 . For example, the latching apparatus  33  has, on one part, a latching lug, which latches into a latching opening in the other part, in order to fixedly connect the two housing parts to one another once the spring force terminal connection  1  has been installed. 
       FIG. 23  shows a perspective view of a third embodiment of a spring force terminal connection  1 . In the exemplary embodiment illustrated, two spring force terminal connections  1  in the open position and rest position are arranged next to one another. The front spring force terminal connection  1  is in the open position, in which the clamping point is open, while the rear spring force terminal connection is in the rest position with the clamping point closed. In contrast to the previously described embodiments, the actuation does not take place by pivoting of an actuating element  13  (actuating lever), but by linear displacement of an actuating element  13  in the form of an actuating thruster. 
     In turn, a bearing arm  22  extends through slots in the clamping spring  4 . To this extent, the clamping spring is comparable to the clamping spring for the previously described second embodiment. Reference is made to the details given in this regard and to  FIGS. 15 to 19 . 
     The bearing arm  22  is likewise mounted with a base  23  between the resting section  5  of the clamping spring  4  and the busbar  2 . The base  23  in turn has a protrusion  25 , which dips into a corresponding trough so as to form a clamping edge  3  on the busbar  2  in order to fix the bearing arm  22  in terms of position on the busbar  2 . 
     The actuating element  13  is manufactured as a separate part from the bearing arm  22  and is mounted linearly displaceably on the arm section  24  of the bearing arm  22 . The actuating element  13  in turn has two actuating fingers  15  which are spaced apart from one another, with the arm section  24  being accommodated between said actuating fingers. The rear end faces of the actuating fingers  15  are arranged so as to be inclined and can possibly also follow a specific curve shape. They rest on the actuating section  7  at the transition to the clamping section  8  on the clamping spring  4 . During a linear displacement of the actuating element  13 , i.e. from right to left in the view in  FIG. 23 , the clamping spring is transferred from the rear rest position illustrated into the front open position illustrated by virtue of the actuating section  7  being pressed downwards in the direction of the clamping section  8 . 
     This becomes clearer again from  FIG. 24 , which shows that the right-hand actuating element  13  in the rest position is pushed forwards. The left-hand actuating element  13  in the open position, on the other hand, is pressed rearwards in the direction of the spring bend  6  of the clamping spring  4 . 
     In order to prevent the actuating element  13  from tipping or falling out upwards, the bearing arm  22  has a cover plate  35 , which is oriented parallel to the busbar  2  or the base  23 , on its upper free end. In this way, in turn a self-supporting spring force terminal connection  1  is provided which can be installed in the preassembled state into an insulating housing. The busbar  2  can in this case be part of the preassembled spring force terminal connection  1 . However, it is also conceivable for the busbar  2  to be located in the electrical device into which the spring force terminal connection is installed without the preassembled busbar  2 . During installation, the spring force terminal connection  1  is then pushed onto the associated busbar  2 . 
       FIG. 25  shows a plan view of the third embodiment of the spring force terminal connections  1  shown in  FIGS. 23 and 24 . It is shown that the upper (rear) spring force terminal connection is in the rest position with a closed clamping point since the actuating element  13  protrudes forwards out of the cover plate  35  counter to the conductor insertion direction (from right to left). In the case of the lower (front) spring force terminal connection  1 , the actuating element (no longer visible) is displaced linearly beneath the cover plate  35  so that an actuating force is exerted on the clamping spring  4  and the clamping point is opened. 
       FIG. 26  shows the lower (front) spring force terminal connection in the open position in the section F-F with the lower closed spring force terminal connection behind said lower spring force terminal connection in the sectional side view. It becomes clear from this that an actuating force can be applied to the clamping spring  4  by virtue of a linear displacement of the actuating element  13  so that the actuating section  7  is pressed downwards in the direction of the resting section  5 , the base  23  and the busbar  2 . 
       FIG. 27  shows a sectional side view in the section G-G of the spring force terminal connection  1  in the rest position. 
     In comparison with  FIG. 27 , it becomes clear that the actuating element  13  is accommodated linearly displaceably on the arm section  24  of the bearing arm  22  and is limited on the upper side by the cover plate  35 . A further guide plate  36  is arranged beneath the actuating element  13  on the arm section  24 , said guide plate being used for guiding the linearly displaceable actuating element  13  on the lower side.