Abstract:
An installation switching device includes a housing having a terminal connecting area and a screwless spring-loaded terminal fixed in position in the terminal connecting area, and a spring operating lever. The screwless spring-loaded terminal includes a clamping spring having a contact limb, a clamping limb having a clamping window with a clamping edge, and a curved spring rear connecting the contact and clamping limbs and configured to interact with a mount part surrounding a clamping strip, such that a connecting conductor is clampable between a rear face of the clamping strip and the clamping edge.

Description:
This is a U.S. National Phase Application under 35 U.S.C. §171 of International Application No. PCT/EP2008/002938, filed on Apr. 14, 2008, which claims priority to German Application No. DE 10 2007 018 960.7, filed on Apr. 21, 2007 and German Application No. DE 10 2008 017 738.5, filed on Apr. 7, 2008. The International Application was published in German on Oct. 30, 2008 as WO 2008/128668 under PCT article 21 (2). 
     The invention relates to an installation switching device having a spring-loaded terminal arrangement. 
     BACKGROUND 
     By way of example, installation switching devices of this generic type may be circuit breakers, residual current devices, motor protective switches or selective main line circuit breakers. A tool by means of which pressure is exerted on the spring leaf is normally required in order to open the spring-loaded terminal. Although the spring-loaded terminal arrangement is then itself of very simple design, an additional control opening must, however, be provided in the housing of the installation switching device, and handling is complicated because of the tool which is required for insertion and removal of the connecting conductor. 
     In order to allow a connecting conductor to be connected to, and removed again from, spring-loaded terminals of this generic type without a tool, it is necessary for the spring-loaded terminal arrangement to have a spring operating means which an operator can use to open the spring-loaded terminal when required, by pushing on the spring leaf. The terminal is closed automatically because of the resetting spring force of the spring leaf, when the pressure is removed from the spring leaf. 
     EP 1 213 791 B1 discloses a spring-loaded terminal arrangement which has an operating lever for the spring leaf, having a spring leaf of the cage type which forms a loop with a triangular profile at the rounded angles, with the two end sections being aligned precisely at right angles to one another, and having an electrically conductive terminal to which the first end section of the spring leaf is fitted, and with an opening passing through the leaf. The operating lever for the leaf is mechanically connected to the terminal, and guide means for the operating lever are fitted to the terminal. The guide means make it possible to keep the lever in constant contact with the spring leaf. When no pressure is applied to the spring leaf, the lever rests on the culmination section of the spring leaf. 
     In this case, the advantage of operability without the use of tools is obtained at the expense of the disadvantage of complicated design of the spring terminal arrangement. 
     SUMMARY OF THE INVENTION 
     An aspect of the present invention is therefore to provide an installation switching device of this generic type in which a connecting conductor can be inserted and removed without any tools, by means of a conventional spring-loaded terminal arrangement of simple design. 
     Thus, according to the invention, a spring operating lever which can be operated from outside the housing is connected to the housing such that it can pivot and has a bending arm which presses on the spring rear during pivoting from a rest position to an open position such that the clamping window releases a clamping opening on the rear face of the clamping strip for insertion of the connecting conductor. 
     An installation switching device according to the invention has the advantage that the spring operating means is disconnected from the terminal and is mounted in the housing. The terminal itself can therefore be of very simple design. The respectively simplest option, which can be installed best, can be chosen for the arrangement of the spring operating means in the housing. 
     According to one advantageous embodiment of the invention, the spring operating lever is a double-armed lever having an operating arm, which projects out of the housing, and a bending arm, which is guided in the interior of the housing. This can be made of plastic, and therefore at very low cost. By way of example, the mounting in the housing may be in the form of a shaft which is connected to the housing in a fixed position. The shaft can also be provided by integrally forming in each case one pin on each side at the point of rotation of the double-armed lever, which pin is mounted such that it can pivot in a respectively corresponding recess in the inside of the housing. 
     According to a further advantageous embodiment, the spring operating lever is fitted such that it remains in its open position by self-locking therein until it is pivoted back to the rest position by hand. For this purpose, the bending arm is advantageously fitted at its free end with a contact surface which is in the form of a cam by means of which it rolls on the spring rear, pressing it, during operation in the opening direction, thus resulting in a continuous opening process and in self-locking of the spring operating lever by a form of latching in the end position of the open position. 
     An embodiment in which the operating arm is formed from two parts, in the form of two arm elements which are pushed one inside the other, is highly advantageous. The operating arm can thus be lengthened by pulling out the second arm element, thus making it possible to achieve a greater lever force during pivoting. 
     In order to ensure guidance of the spring operating lever in the installation switching device, in one particularly advantageous embodiment, a first guide means can be fitted to the spring operating lever and a second guide means can be fitted in the interior of the housing shells, which guide means interact for guidance of the spring operating lever. The clamping spring itself has no guide means and is therefore of very simple design. 
     According to a further advantageous embodiment, a locking device can be fitted in the interior of the housing shells and is able to interact with the first guide means of the spring operating lever in the open position, so as to prevent inadvertent pivoting of the spring operating lever from the open position to the rest position. This offers a redundant capability, in addition to the self-locking already mentioned above, of preventing inadvertent pivoting of the spring operating lever from the open position to the rest position. 
     The spring operating lever is advantageously arranged such that, in the rest position, it projects such that it is flush with the rearward front face of the housing and at right angles to the associated narrow face, and, in the open position, is pivoted toward the forward front face such that, in the open position, it projects at right angles to the rearward front face and such that it is approximately flush with the associated narrow face. 
     According to a further advantageous embodiment, the second guide means is a curved groove and the first guide means is a guide pin on the spring operating lever. 
     A locking contour can be fitted to the housing inner face in the area in which the guide pin is located when the spring operating lever is located in the open position, and the spring operating lever can then be movable in the direction of the locking contour when in the open position, such that the guide pin is coupled to the locking contour and thus prevents inadvertent pivoting of the spring operating lever from the open position to the rest position. 
     In this case, the locking contour may advantageously be a web, which projects on the inner wall of the housing, or an undercut. 
     Further advantageous refinements and improvements of the invention, as well as further advantages, can be found in the dependent claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention as well as further advantageous refinements and improvements of the invention will be explained and described in more detail with reference to the drawings, which illustrate one exemplary embodiment of the invention, and in which: 
         FIG. 1  shows a first embodiment of a spring operating lever according to the invention, in the retracted state, 
         FIG. 2  shows the spring operating lever as shown in  FIG. 1 , in the extended state, 
         FIG. 3  shows the spring operating lever as shown in  FIG. 1 , in the retracted state, in its installed position in the housing, 
         FIG. 4  shows the spring operating lever as shown in  FIG. 1 , in the extended state, in its installed position in the housing, 
         FIG. 5  shows the spring operating lever as shown in  FIG. 1 , illustrated in the open position, in its installed position in the housing, 
         FIG. 6  shows the spring operating lever as shown in  FIG. 5 , with the housing partially open, 
         FIG. 7  shows the spring operating lever as shown in  FIG. 6 , in a partially pivoted position, 
         FIG. 8  shows a spring operating lever as shown in  FIG. 1 , viewed from underneath, 
         FIG. 9  shows a spring operating lever as shown in  FIG. 2 , viewed from underneath, 
         FIG. 10  shows a spring operating lever with the associated clamping spring, installed in the terminal accommodation area of an installation switching device, in the rest position, 
         FIG. 11  shows a spring operating lever with the associated clamping spring, installed in the terminal accommodation area of an installation switching device, in the open position, 
         FIG. 12  shows a spring operating lever as shown in  FIG. 1 , in the separated state, 
         FIG. 13  shows the spring operating lever as shown in  FIG. 12 , in the assembled state, 
         FIG. 14  shows a further embodiment of a spring operating lever, in its installed position in the terminal accommodation area of an installation switching device, in the retracted state and in its rest position, 
         FIG. 15  shows a further embodiment of a spring operating lever, in its installed position in the terminal accommodation area of an installation switching device, in the extended state and in its rest position, 
         FIG. 16  shows the spring operating lever as shown in  FIG. 15 , in its open position, 
         FIG. 17  shows the spring operating lever as shown in  FIG. 16 , seen in the direction of the arrow A, 
         FIG. 18  shows the spring operating lever as shown in  FIG. 16 , partially inserted and locked in its open position, 
         FIG. 19  shows the spring operating lever as shown in  FIG. 18 , seen in the direction of the arrow A, 
         FIG. 20  shows the spring operating lever as shown in  FIG. 18 , inserted and unlocked in its open position, and 
         FIG. 21  shows the spring operating lever as shown in  FIG. 20 , seen in the direction of the arrow A. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 10  will be considered first of all. This shows a spring operating lever  10  with the associated clamping spring  20 , installed in the terminal accommodation area  32  of an installation switching device  30 , in the rest position. The installation switching device  30  may be a circuit breaker, a main switch, a motor protective switch or the like. Its housing is composed of insulating material, and is indicated schematically. This comprises a forward front face  31 , a rearward front face  33 , a forward narrow face  34 , a rearward narrow face  35  and an attachment face. A broad face, which connects the front and narrow faces parallel to the plane of the drawing, is likewise provided, but is not shown in the illustration in  FIG. 10 . This is indicated in the perspective illustration in  FIG. 5 . 
     An installation switching device  30  is normally used to monitor and/or to switch a current path which is passed through said device between two connecting terminals. Further assemblies and elements are provided for this purpose in the interior of the installation switching device, for example at least one contact point comprising a moving contact piece and a stationary contact piece, a moving contact lever, a latching mechanism for operating the contact lever, one or more tripping assemblies, for example a thermal overcurrent release, and/or a magnetic impact-type armature system, an operating lever for manual operation from the outside, an indication apparatus for indication of the switching state, and more items of a similar kind. Attachment apparatuses may be located on the attachment face  36 , by means of which the installation switching device can be fitted to mounting rails or else to busbars in installation distribution systems. The internal design and the external connecting and attachment apparatuses of an installation switching device will be assumed to be already known, for the purposes of the present invention. 
     The connecting terminals are in this case accommodated in terminal accommodation areas, one of which is annotated with the reference number  32  in  FIG. 10 . The terminal accommodation area  32  is located in the area of the rearward narrow face  35 , in the vicinity of the rearward front face  33 . 
     A clamping spring  20  is mounted in the terminal connecting area  32 . The spring leaf of the clamping spring forms a loop with a triangular contour and rounded corners. The clamping spring therefore has a contact limb  21 , by means of which it rests on the free end of a busbar  22  which forms the connection to the current path into the device interior. The free end  23  of the busbar  22  is in this case also referred to as a clamping strip, and the busbar  22  is also referred to as a mount part. 
     The clamping spring  20  also has a clamping limb  24  which runs approximately at right angles to the contact limb  21 . A rectangular cutout, which is referred to as a clamping window  25 , is provided in the clamping limb  24 , and its lower edge forms the clamping edge  26 . 
     The contact limb  21  and the clamping limb  24  are connected by means of the spring rear  27 . The clamping limb  24  can be pushed downward by pressure from above on the spring rear  27 , that is to say toward and at right angles to the contact limb  21 , as a result of which the clamping window is forced onto that side of the clamping strip which faces away from the contact limb  21 . This position is illustrated in  FIG. 11  which shows the clamping spring  20  in the open position. A connecting conductor can now be inserted into the clamping window  25  from the rearward narrow face  35 . When the pressure is removed from the spring rear, then it moves the clamping limb  24  back again in the direction of the rest position, by virtue of its spring characteristic. In the process, the inserted connecting conductor is then firmly clamped between the clamping edge  26  and that side of the clamping strip  23  which faces away from the contact limb  21 . 
     In order to operate the clamping spring, that is to say to apply the pressure required for opening to the spring rear, a spring operating lever  10  is fitted in the installation switching device and is mounted such that it can rotate on a shaft  11  which is coupled to the housing. The spring operating lever  10  is a double-armed lever with an operating arm  12  which projects from the housing, and with a bending arm  13  which runs in the interior of the housing. The operating arm  12  acts as a handle for operation of the clamping spring  20 . The bending arm  13  causes the sprung loop to act on the spring rear  27 . 
     In the rest position, the operating arm  12  projects at right angles to the rearward narrow face  35  and flush with the rearward front face of the housing. It therefore at the same time acts as a closure for the terminal accommodation area  32  in the area of the junction between the rearward front face  33  and the rearward narrow face  35 . 
     At its free end, the bending arm  13  of the spring operating lever  10  is fitted with a contact surface  14  which is curved in the form of a cam. This contact surface  14  is bent away from the spring rear  27 . At its end, the bending arm  13  has a flat  15 . 
     When the spring operating lever  10  is pivoted by hand by an operator from the rest position as shown in  FIG. 10  to the open position as shown in  FIG. 11 , about the shaft  11 , then the contact surface  14  of the bending arm  13  in the process rolls on the spring rear  27 , bending the latter to its open position. The rolling process results in a smooth movement during opening of the clamping spring, preventing tilting of the spring operating lever  10  with the clamping spring  20 . 
     At the end of the opening movement, the spring operating lever  10  then projects at right angles to the rearward front face  33  in its open position, see  FIG. 11 . In its end position, the flat  15  on the bending arm  13  then holds the clamping spring in its open position. In this case, the flat  15  rests flat on the spring rear. The resetting force of the clamping spring acts via the flat  15  at right angles to the bearing shaft  11  of the spring operating lever. This to a certain extent ensures self-locking or latching of the spring operating lever  10  in the open position. The spring operating lever cannot fall back on its own from the open position to the rest position. 
     The spring operating lever  10  is thus mounted in the housing and is actually not connected to the terminal. The terminal itself does not have guide means for the spring operating lever  10 , and instead the guide means for the spring operating lever  10  are provided in the interior of the housing shells. The functions of “clamping” and “operating” are thus provided in separate assemblies. 
     The spring operating lever  10  is formed in two parts. This will now be explained with reference to  FIGS. 8 ,  9 ,  12  and  13 . The spring operating lever  10  comprises a core part  101  and a casing part  102  which is pushed over the core part  101  and has an internal recess for holding the core part. The core part  101  forms a double-armed lever, one of whose arms forms the operating arm  12  of the spring operating lever  10 . The other arm forms an operating projection  103 , onto which the casing part  102  is pushed in the form of a screen. The casing part  102 , which is pushed onto the operating projection  103 , therefore forms the operating arm  12  of the spring operating lever. 
     The free end of the operating projection  103  is fitted with two spring arms  104 ,  105 , which run parallel and are fitted with a respective latching tab  106 ,  107  at their free ends. 
     After the casing part  102  has been pushed onto the core part  101 , it can be moved on the latter, and in the process can assume three fixed positions. These are an inserted position as shown in  FIG. 8 , an extended position as shown in  FIG. 9 , and a mid-position as shown in  FIG. 13 . 
     First undercuts  108 ,  109  are located in a corresponding manner in the interior of the recess of the casing part  102 , in the vicinity of the free end of the casing part, and are arranged such that they latch with the latching tabs  106 ,  107  in the inserted position. There are also second undercuts  110 ,  111  in the vicinity of that end of the casing part which faces the operating arm, and in the interior of the casing part, which undercuts  110 ,  111  are arranged such that they latch with the latching tabs  106 ,  107  in the extended position. Finally, located in-between, there are third undercuts  112 ,  113  which are arranged such that they latch with the latching tabs  106 ,  107  in the mid-position. In each of the three positions which the casing part can assume on the core part, the casing part is therefore held by the latching tabs  106 ,  107  latching with the corresponding undercuts. 
     The advantageous effect is that the effective lever arm of the operating arm is lengthened by pulling out the casing part  102 , thus making it possible to achieve a greater lever force during operation of the spring. 
     Bearing journals  16  which project at the side are integrally formed on the core part  101  and are used for mounting the spring operating lever such that it can pivot, in depressions  17  which are incorporated at an appropriate position in the housing broad face. This allows particularly simple fitting. The spring operating lever  10  comprises only two parts, which can be produced completely as injection-molded parts, for example from plastic, and therefore at very little cost. The depressions for mounting the spring operating lever in the housing broad face are also incorporated in the housing parts while they are being injection molded. As an alternative to this, however, the spring operating lever could also be mounted by means of a bearing shaft. A bearing hole in the spring operating lever would then be pushed over the bearing shaft during assembly. 
       FIG. 1  once again shows the spring operating lever  10  in the inserted position, from above, as an operator would see it when in the installed state, and when looking at the rearward narrow face  35 . The undercuts and the spring arms of the core part cannot be seen from this side. 
       FIG. 3  shows the spring operating lever as shown in  FIG. 1 , installed in an installation switching device, in the rest position. 
       FIG. 2  shows the spring operating lever as shown in  FIG. 1 , in the extended position, and  FIG. 4  shows the spring operating lever in the extended position, installed in an installation switching device and in the rest position. 
       FIG. 5  shows the spring operating lever as shown in  FIG. 2 , now installed in its open position in the housing, and pivoted upward. 
     Two guide pins  114 ,  115  are integrally formed on the casing part, close to its insertion opening for the core part, in such a way that these guide pins  114 ,  115  project opposite and at the side, in the axial direction. In the extended position, the guide pins  114 ,  115  are located between the bearing journals  16  and the free end of the operating arm  12 . In the inserted position, the guide pins  114 ,  115  are located between the bearing journals  16  and the free end of the bending arm  13  of the spring operating lever. In the mid-position, the guide pins  114 ,  115  are located approximately above the bearing journals  16 . 
     When the spring operating lever  10  pivots, the guide pins  114 ,  115  run in a guide groove  38  in the inner wall of the housing broad face, see  FIG. 7 . This additionally defines the movement path of the spring operating lever  10 . 
     In the illustration shown in  FIG. 7 , the spring operating lever is located in the inserted position, and is illustrated in an intermediate position between the rest position and the open position. In the illustration shown in  FIG. 6 , the spring operating lever is shown in its open position, and is partially pulled out to its mid-position. In this position, the guide pins  114 ,  115  latch with a latching projection  39  which is fitted at an appropriately corresponding point at the side in the housing broad face. The spring operating lever  10  is therefore additionally locked in its open position, making it difficult for the terminal to be closed inadvertently. The spring operating lever cannot be pivoted back to its rest position again until it has been pushed from the mid-position to the inserted position again. 
     The various operating and handling options for the spring operating lever are illustrated once again in  FIGS. 14 to 21 .  FIG. 14  shows the spring operating lever  10  in its rest position, and the casing part  102  in its inserted position. The spring operating lever is aligned with the rearward front face  33  of the housing. The guide pin  115  is located to the right of the shaft  16 . 
     In  FIG. 15 , the casing part  102  has been pulled to its extended position, with the spring operating lever  10  in the rest position. The guide pin is now located to the left of the shaft  16 . In this position, the lever arm of the operating arm has been lengthened. 
       FIG. 16  shows the position of the spring operating lever to which it has been moved by pivoting from the position shown in  FIG. 15  to the open position. The guide pin  115  is now located above the shaft  16 . It is free of the latching projection  39 , as a result of which the spring operating lever  10  can be pivoted.  FIG. 17  shows the view from the direction of the arrow A of the spring operating lever in the position shown in  FIG. 16 . The latching tabs  106 ,  107  are latched to the second undercuts  110 ,  111 , thus making it more difficult to push the casing part  102  back inadvertently. 
     In  FIG. 18 , the casing part has been partially retracted to its mid-position. In this position, the guide pin has been pushed behind the latching projection  39 , and is held firmly by it. This blocks pivoting of the spring operating lever back to the rest position.  FIG. 19  shows the view from the direction of the arrow A of the spring operating lever in the position shown in  FIG. 18 . The latching tabs  114 ,  115  have been latched to the third undercuts  112 ,  113 , thus making it more difficult for the casing part  102  to be moved inadvertently from its mid-position. 
     In  FIG. 20 , the casing part has once again been pushed to its retracted position, with the spring operating lever  10  in the open position. The guide tabs  114 ,  115  have once again become free of the latching projection  39 , and they are now located underneath the bearing journal  16 , which forms the pivoting shaft. In this position, the spring operating lever can be pivoted back again to its rest position, as a result of which it would then once again assume the position shown in  FIG. 14 .  FIG. 21  shows the view from the direction of the arrow A of the spring operating lever in the position shown in  FIG. 20 . The latching tabs  114 ,  115  have been latched to the first undercuts  106 ,  107 , thus likewise making it more difficult for the casing part  102  to be moved inadvertently from its retracted position. 
     The installation switching device according to the invention therefore has various safety mechanisms for prevention of inadvertent operation of the spring operating lever. When the lever is positioned vertically and the terminal is therefore open, the casing part can be pushed in somewhat, as a consequence of which the guide pin latches and thus prevents the terminal from being closed inadvertently. Only when the casing part is moved out of its locking position again, or is pushed downward further, does the guide pin unlatch, allowing the terminal to close. 
     LIST OF REFERENCE SYMBOLS 
     
         
           10  Spring operating lever 
           11  Shaft of the spring operating lever 
           12  Operating arm 
           13  Bending arm 
           14  Contact surface 
           15  Flat 
           16  Bearing journal 
           17  Depression 
           20  Clamping spring 
           21  Contact limb 
           22  Busbar 
           23  Clamping strip 
           24  Clamping limb 
           25  Clamping window 
           26  Clamping edge 
           27  Spring rear 
           30  Installation switching device 
           31  Forward front face 
           32  Terminal accommodation area 
           33  Rearward front face 
           34  Forward narrow face lever 
           35  Rearward narrow face 
           36  Attachment face 
           37  Broad face 
           38  Guide groove 
           39  Latching projection 
           101  Core part 
           102  Casing part 
           103  Operating projection 
           104  Spring arm 
           105  Spring arm 
           106  Latching tab 
           107  Latching tab 
           108  First undercut 
           109  First undercut 
           110  Second undercut 
           111  Second undercut 
           112  Third undercut 
           113  Third undercut 
           114  Guide pin 
           115  Guide pin