Abstract:
A latching mechanism is for locking a spring energy store of an electric switching device. The store is tensioned by a rotary drive and an extensible lever system. In the latching mechanism, the extensible lever system is locked with the spring energy store under tension by way of a support element, an auxiliary lock and a primary lock, in addition to a stop that is allocated to the primary lock. The auxiliary lock can be pivoted by the extension of the lever system and the position of the primary lock during the pivoting of the auxiliary lock can be influenced by working surfaces that are allocated to one another. To configure the locking mechanism for pivoting the primary lock in a manner which obviates the use of a return spring that acts on said primary lock, the auxiliary lock and the primary lock respectively have at least two working surfaces. In a first pivoting phase of the auxiliary lock, the respective first surfaces of the two sets of working surfaces lie adjacent to one another and in a second pivoting phase of the auxiliary lock, the second working surfaces lie adjacent to one another, intermeshing in the manner of a toothed gear.

Description:
This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/DE02/01156 which has an International filing date of Mar. 26, 2002, which designated the United States of America and which claims priority on German Patent Application number DE 101 20 783.2 filed Apr. 23, 2001, the entire contents of which are hereby incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention generally lies in the area of electrical switches. Preferably, it relates to switches equipped with a spring-powered drive for actuating contacts, and more preferably one to be used for the configuration of a latching mechanism for locking a spring energy store. 
   BACKGROUND OF THE INVENTION 
   In the case of a known latching mechanism for a spring-powered drive, in which the associated spring energy store is tensioned by use of a rotary drive and an extensible toggle lever system, the extensible toggle lever system is locked with the spring energy store under tension by a support element, an auxiliary lock and a primary lock in addition to a stop allocated to the primary lock. In the case of this latching mechanism, in which the supporting element designed as a lever is articulated on the one hand on the toggle joint of the toggle lever system and on the other hand on the auxiliary lock, the auxiliary lock can be pivoted by extension of the lever system. 
   In this case, the auxiliary lock and the primary lock have working surfaces allocated to one another, by which the position of the primary lock during the pivoting of the auxiliary lock can be influenced (DE 44 16 088 C1). In this case, a first working surface of the auxiliary lock is formed by a semicircular portion of the peripheral edge of the auxiliary lock which lies adjacent to a working surface of the primary lock designed as a roller, and keeps the primary lock in a first position counter to the force of the return spring allocated to it. In this first position, a half-shaft forming the stop is locked by the primary lock under spring pretension. 
   A second working surface, which is designed as a set-back edge and is likewise allocated to the roller, releases the primary lock at the end of the tensioning operation, so that on the one hand the primary lock pivots under the force of the return spring allocated to it in overtravel behind the half-shaft. On the other hand, the released half-shaft pivots on account of its spring pretension into the path of movement of the primary lock. Both pivoting operations must proceed before the primary lock pivots in the reverse direction by decoupling of the lever system from the rotary drive under the effect of the force of the spring energy store. 
   Since an indicating element for the state of the spring energy store is usually coupled to the primary lock, it is at the same time expedient with regard to the certainty of the indication that the primary lock pivots in overtravel behind the half-shaft only shortly before the decoupling of the lever system from the rotary drive. For this purpose, rapid movements of the latching mechanism are required, in particular when there is a high energy content of the spring energy store. In the case of the latching mechanism, the return spring allocated to the primary lock must therefore provide a correspondingly high returning force. This returning force is then in turn to be taken into account when configuring the latching mechanism with regard to its force reduction and when configuring the mechanisms providing the triggering force for releasing the locking. 
   SUMMARY OF THE INVENTION 
   To lock the tensioned spring energy store securely, it is necessary in particular for the tolerance range of the force under which the primary lock lies adjacent to the stop and the tolerance range of the force which is necessary for releasing the locking to be adapted to the tolerance range of the return spring. If there is a rupture of the return spring allocated to the primary lock, locking of the tensioned spring energy store is not possible. 
   On the basis of a latching mechanism, an embodiment of the invention is based on an object of configuring the latching mechanism for pivoting the primary lock in a manner which obviates the use of a return spring which acts on the primary lock. 
   According to an embodiment of the invention, an object may be achieved by the auxiliary lock and the primary lock respectively having at least two working surfaces. In a first pivoting phase of the auxiliary lock, respective first surfaces of the two sets of working surfaces lie adjacent to one another. Further, in a second pivoting phase, the second working surfaces lie adjacent to one another, intermeshing in the manner of a toothed gear. 
   On account of a configuration of this type, it is ensured that the primary lock is forcibly pivoted at the end of the tensioning operation to the extent that it reliably comes into adjacent contact with the stop under the effect of the force of the spring energy store when the lever system is decoupled from the rotary drive. Since, in particular when there is a high energy content of the spring energy store, no high returning forces have to be taken into account in the configuration of the latching mechanism, both a low tolerance range of the force under which the primary lock lies adjacent to the stop and a low tolerance range of the triggering force can be provided. 
   There is in fact a known latching mechanism for locking a spring energy store, in which a primary lock can be pivoted without using a return spring acting on the primary lock (DE 37 33 916 A1). In the case of this known latching mechanism, the primary lock is moved by an extensible lever system, without an auxiliary lock being interposed. It is thereby transferred in particular in overtravel behind a stop allocated to the primary lock. 
   An expedient development of the novel latching mechanism provides that on the one hand, the first working surface of the auxiliary lock is formed by a pin of the auxiliary lock protruding transversely with respect to the pivoting plane. Further, the second working surface of the auxiliary lock is formed by a concavely shaped portion of the peripheral edge of the auxiliary lock. On the other hand, the first working surface of the primary lock is formed by a lug of the primary lock and the second working surface is formed by a roller held on the primary lock. 
   In order when tensioning the spring energy store to transmit part of the force of the rotary drive and when detensioning the spring energy store to transmit part of the force of the spring energy store uniformly to the auxiliary lock in a space that is as small as possible, in a further refinement of an embodiment of the invention it is provided that, in the case of the locked position of the lever system, a roller which forms the supporting element and is arranged on a joint bolt of the lever system lies adjacent to a second concavely shaped portion of the peripheral edge of the auxiliary lock. 
   Furthermore, at the end of the tensioning phase, a small amount of travel which transmits from the rotary drive to the lever system can be converted into a large, and consequently abrupt, pivoting movement of the auxiliary lock. This can be done independently of the pivoting movement of the supporting element coupled to the lever system, if in a further refinement of an embodiment of the invention a driver coupled to the lever system and a two-armed pivotable control lever are provided for controlling the pivoting movement of the auxiliary lock, the first lever arm of the control lever protruding into an end portion of the path of movement of the driver and the second lever arm being allocated to a driving surface of the auxiliary lock. For controlling the auxiliary lock, in addition to the first driver and the control lever there may be provided a second driver, which is coupled to the lever system and during the extension of the lever system lies adjacent over a portion of its path of movement to a second driving surface of the auxiliary lock. 
   Maintaining a form of construction of the latching mechanism that is as small as possible is in this case made possible by the fact that the first driver is formed by the joint bolt of the lever system. The joint bolt can be allocated a lug-like projection of the control lever as its first lever arm. Further, there can be formed, on the second lever arm of the control lever, a pin which engages in a slot, which is formed close to the pivot point of the auxiliary lock and the inner edge of which forms the first driving surface. The second driver may be designed as a bolt which forms the toggle joint of a toggle lever connection coupled to the lever system, the second driving surface being formed by a further portion of the peripheral edge of the auxiliary lock. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description of preferred embodiments, including an exemplary embodiment of the novel latching mechanism, given hereinbelow and the accompanying drawings, which are given by way of illustration only and thus are not limitative of the present invention, and wherein: 
       FIG. 1  shows the latching mechanism with the spring energy store fully relaxed, 
       FIGS. 2  to  6  show the latching mechanism in five different phases of the tensioning process and 
       FIG. 7  shows the latching mechanism with the spring energy store completely tensioned and locked. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1  to  7  show a latching mechanism integrated into a drive device for a low-voltage circuit breaker. The drive device, which serves for the actuation of a switching contact arrangement not represented in the figures, has in this case a spring energy store  1 , designed as a helical compression spring, for providing the actuating energy. Provided in the case of this drive device for tensioning the spring energy store  1  is a lever system which can be extended by way of a rotary drive and for the locking of which the latching mechanism serves. 
   The lever system is in this case formed by a roller lever  3  bearing a sensing roller  2 , a tensioning lever  4  articulated on the spring energy store  1  and a coupling element  5  connecting the roller lever  3  to the tensioning lever  4 . The roller lever  3  is pivotably arranged on a first bearing bolt  6  and the tensioning lever  4  is pivotably arranged on a second bearing bolt  7 . 
   In this case, the roller lever  3  and the coupling element  5  are connected by means of a first joint bolt  8  and the tensioning lever  4  and the coupling element  5  are connected by a second joint bolt  9 . The tensioning lever  4  is designed as a two-armed lever, the one arm being articulated on the coupling element  5  and the other arm being articulated on the spring energy store  1 . Of the rotary drive, which may be operated for example by an electric motor and/or by a hand lever, only a tensioning shaft  10  which can rotate clockwise and a cam disk  11  which is fixedly arranged on the tensioning shaft  10  are respectively shown in  FIGS. 1  to  7 . 
   The cam disk  11  and the lever system  3 ,  4  and  5  are coupled for the transmission of the driving force of the rotary drive as soon as the sensing roller  2  borne by the roller lever  3  lies adjacent to the peripheral edge of the cam disk  11 . 
   The latching mechanism has, on the one hand, for locking the lever system, a supporting element, which is designed as a roller  12 , an auxiliary lock  14 , which is pivotable about a third bearing bolt  13 , a primary lock  16 , which is pivotable about the first bearing bolt  6 , and also a stop  17 , which is allocated to the primary lock  16 . On the other hand, for controlling the pivoting movement of the auxiliary lock  14 , it includes a first driver, which is formed by the first joint bolt  8  of the lever system and acts via a two-armed control lever  19  on a first driving surface  20  of the auxiliary lock  14 . It further includes a second driver  22 , which forms the toggle joint of a toggle lever connection  21  coupled to the lever system and acts directly on a second driving surface  23  of the auxiliary lock  14 . 
   To influence the pivoting movement of the primary lock  16  during the pivoting of the auxiliary lock  14 , on the one hand a first working surface, formed by a pin  24 , and a second working surface, formed by a first concavely shaped portion  25  of the auxiliary lock, are provided on the auxiliary lock  14 . On the other hand, a first working surface, allocated to the pin  24  and formed by a lug  26  of the main lock, and a second working surface, allocated to the first concavely shaped portion  25  and formed by a roller  27  held on the primary lock, are provided on the primary lock  16 . In this case, during the clockwise pivoting of the auxiliary lock  14  (i.e. under the effect of the force of the rotary drive  10  and  11 ), the primary lock  16  is turned counterclockwise as soon as firstly the pin  24  and the lug  26  and later, intermeshing in the manner of a toothed gear, the first concavely shaped portion  25  of the peripheral edge of the auxiliary lock and the roller  27  lie adjacent to one another. 
   The lever system  3 ,  4  and  5  is locked as soon as the roller  12  forming the supporting element and arranged on the first joint bolt  8  of the lever system lies adjacent to a second concavely shaped portion  28  of the peripheral edge of the auxiliary lock, the first concavely shaped portion  25  of the auxiliary lock lies adjacent to the roller  27  of the primary lock and the primary lock  16  lies adjacent to the stop  17  designed as a half-shaft. Coupled to the primary lock is an indicating element  29 , which signals the state of the spring energy store. For this purpose, a pin  30  formed on the primary lock engages in a curved slot  31  of the indicating element  29  in such a way that, when the auxiliary lock  16  pivots, the indicating element pivots along with it. 
     FIG. 1  shows the latching mechanism before the beginning of the tensioning process. At this point in time, the cam disk  11  is in its starting position and the sensing roller  2  borne by the roller lever  3  lies adjacent to the peripheral edge of the cam disk  11 . The lever system  3 ,  4  and  5  is in a first position, in which the spring energy store  1  is completely relaxed. In this case, the primary lock  16  is supported on a stop bolt  32 , the auxiliary lock  14  is supported by way of a straight portion  33  of its peripheral edge adjacent to the roller  27  of the primary lock  16  on the primary lock  16 , and the roller  12  coupled to the lever system  3 ,  4  and  5  and forming the supporting element is supported on a third concavely shaped portion  34  of the peripheral edge of the auxiliary lock. 
   A portion  35  of the peripheral edge of the primary lock  16  in this case lies underneath the half-shaft  17  in such a way that the half-shaft  17 , which is rotatable by means of triggering mechanisms not represented any further against the force of a return spring likewise not represented, is held under spring pretension. The indicating element  29 , which is coupled to the primary lock  16  and provided with an indicating surface  36 , is in this case in a first position, in which a first subregion  39  of the indicating surface  36  of the indicating element lies opposite a viewing window not represented. This first subregion  37  signals that the spring energy store  1  is not completely tensioned. A symbol suitable for this is, for example, a compression spring shown relaxed. At the point in time represented in  FIG. 1 , neither does the first driver  18  lie adjacent to the control lever  19  nor does the second driver  22  lie adjacent to the second driving surface  23  of the auxiliary lock. 
   According to  FIGS. 2  to  6 , which show the latching mechanism during various phases of the tensioning process, the lever connection of the lever system formed by the roller lever  3  and the coupling element  5  is established by the bolt  40 , bearing the sensing roller, and consequently also the roller lever  3 , pivoting counterclockwise as the distance of the peripheral edge of the cam disk  11  from the pivot point  39  of the cam disk increases. 
   The movement of the roller lever  3  is transmitted by way of the coupling element  5  to the tensioning lever  4 , so that the arm of the tensioning lever articulated on the spring energy store  1  is pivoted clockwise about the second bearing bolt  7  and the spring energy store  1  is thereby tensioned. At the point in time represented in  FIG. 1 , the second driver  22  comes into adjacent contact with the second driving surface  23  of the auxiliary lock and pivots the auxiliary lock  14  clockwise about the third bearing bolt  13  until, according to  FIG. 3 , the pin  24  which is formed on the auxiliary lock  14  and protrudes from the auxiliary lock perpendicularly with respect to the pivoting plane of the auxiliary lock runs against the lug  26  formed on the primary lock  16 . 
   At this point in time, the first driver  20  runs against a first arm  41 , protruding into an end portion of its path of movement and formed as a lug-like projection of the control lever, and pivots the control lever counterclockwise about its pivot point formed by the first bearing bolt  6 . This pivoting movement is transmitted to the auxiliary lock via the second arm  42  of the control lever, which is made longer than the first arm. For this purpose, a control pin  43  protruding from the control lever transversely with respect to the pivoting direction of the control lever is arranged at the end of the longer, second arm  42  of the control lever  19 . This control pin  43  protrudes into a second curved slot  44 , which is formed close to the third bearing bolt  13  (pivot point of the auxiliary lock) and the inner edge of which forms the second driving surface of the auxiliary lock. 
   Since the distances of the working surfaces  24  and  25 , formed on the auxiliary lock  14 , from the pivot point of the auxiliary lock  13  are greater than the distance of the control pin  43  of the control lever from the pivot point of the auxiliary lock  13 , and since furthermore the distances of the working surfaces of the primary lock  26  and  27  from the first bearing bolt  6  (pivot point of the primary lock) are less than the distance of a portion  45  of the peripheral edge of the auxiliary lock that is allocated to the stop  17  from the pivot point of the primary lock, according to  FIGS. 3  to  6  at the end of the tensioning process a small arc length of the pivoting movement of the first driver  8  is converted into a large arc length of the pivoting movement of the portion  45  of the peripheral edge of the primary lock that is allocated to the stop. For this purpose, in a first pivoting phase according to  FIGS. 3 and 4 , the first working surfaces  24  and  26  of the auxiliary lock and of the primary lock respectively lie adjacent to one another. 
   During the transition into a second pivoting phase of the auxiliary lock, in which according to  FIGS. 5 and 6  the second working surfaces  25  and  27  lie adjacent to one another, intermeshing in the manner of a toothed gear, they are decoupled from one another. In this second pivoting phase of the auxiliary lock, the portion  45  of the peripheral edge of the primary lock that is allocated to the stop passes in overtravel behind the stop  17  shortly before the sensing roller  2  of the roller lever  3  is decoupled from the peripheral edge of the cam disk  11 . 
   According to  FIG. 7 , which shows the latching mechanism with the spring energy store  1  completely tensioned and locked, the lever system, decoupled from the rotary drive, is supported under the force of the spring energy store  1  via the supporting element  12 , coupled to the lever system, on the third concavely shaped portion  34  of the peripheral edge of the auxiliary lock, the rotary lock  14  is supported via the second working surfaces  25  and  27  on the primary lock  16  and the primary lock is supported on the stop  17 . At this point in time, the indicating element  29 , coupled to the primary lock, is in a second position, in which a second subregion  38  of the indicating surface  36  lies opposite the viewing window. This second subregion  38  signals that the spring energy store  1  is completely tensioned. A symbol suitable for this is, for example, a compression spring shown tensioned. 
   To keep the play between the mutually allocated working surfaces of the auxiliary lock and of the primary lock as small as possible, a spring acting on the primary lock may be provided, for example. 
   List of Designations 
   
       
         1  Spring energy store 
         2  Sensing roller 
         3  Roller lever 
         4  Tensioning lever 
         5  Coupling element 
         6  First bearing bolt (bearing bolt of the roller lever of the primary lock and of the two-armed control lever) 
         7  Second bearing bolt (bearing bolt or pivot point of the tensioning lever) 
         8  First joint bolt; forms the first driver 
         9  Second joint bolt (joint bolt between tensioning lever and coupling element) 
         10  Tensioning shaft 
         11  Cam disk 
         12  Roller which forms the supporting element 
         13  Third bearing bolt (bearing bolt or pivot point of the auxiliary lock) 
         14  Auxiliary lock 
         16  Primary lock 
         17  Stop 
         19  Two-armed control lever 
         20  First driving surface of the auxiliary lock 
         21  Toggle lever connection 
         22  Second driver 
         23  Second driving surface 
         24  Pin (first working surface of the auxiliary lock) 
         25  First concavely shaped portion of the peripheral edge of the auxiliary lock (second working surface of the auxiliary lock) 
         26  Lug of the primary lock (first working surface of the primary lock) 
         27  Roller held on the primary lock (second working surface of the roller) 
         28  Second concavely shaped portion of the peripheral edge of the auxiliary lock 
         29  Indicating element 
         30  First curved slot of the indicating element 
         32  Stop bolt 
         33  Straight portion of the peripheral edge of the auxiliary lock 
         34  Third concavely shaped portion of the peripheral edge of the auxiliary lock 
         35  Portion formed on the peripheral edge of the primary lock 
         36  Indicating surface of the indicating element 
         37  First subregion of the indicating surface 
         38  Second subregion of the indicating surface 
         39  Pivot point of the cam disk 
         40  Bolt which bears the sensing roller 
         41  First arm of the two-armed control lever 
         42  Second arm of the control lever 
         43  Control pin 
         44  Second curved slot, which is formed in the auxiliary lock 
         45  Portion of the peripheral edge of the primary lock that is allocated to the stop 
     
  
   Exemplary embodiments being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.