Abstract:
A motor-operated remote-control mechanism for electrical switching devices, especially for circuit breakers, can be used for different sizes with different switching characteristics, while taking necessary safety measures into account. The mechanism consumes as little power as possible and has a simple structure. The circuit breaker is screwed onto a frame. The mechanism can be adapted to several sizes of circuit breakers by using different frames combined with different types of mechanism assemblies with and without a snap-action function.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation of copending International Application No. PCT/DE98/02872, filed Sep. 28, 1998, which designated the United States. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a motor-operated mechanism for electrical switching devices, which is intended in particular for circuit-breakers. The coupling of the mechanism to the circuit-breaker is possible through a knob or a latching mechanism. 
     Coupling to a knob is advisable in order to obtain optimum devices and make them as narrow as possible. In that case, motor-operated mechanisms which bring about snap-action closing of the circuit-breaker are known. Those are described, inter alia, in French Patent Application 2 476 906, European Patent Application 0 034 966 A1, European Patent Application 0 150 756 A2, corresponding to U.S. Pat. No. 4,649,244, and European Patent Application 0 506 066 A1. Those mechanisms are relatively complex. In contrast therewith, there are motor-operated mechanisms having a simpler type of construction for circuit-breakers which themselves have snap-action closing. Such a mechanism is described in German Patent DE 690 24 176 T2. Those are generally unsuitable for circuit-breakers without a snap-action mechanism, since the switching speed is too low. The remote-controlled mechanisms in most cases are screwed onto the circuit-breaker and are constructed specifically for the characteristics of the respective breaker. In order to activate the motor-operated mechanism by a programmable controller, an actuating current should be kept as small as possible. As a result, actuation through the use of an operating magnet or, as in European Patent Application 0 506 066 A1, tripping of a latch through the use of a tripping magnet, appear to be disadvantageous. Manual actuation must be possible at any time. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a motor-operated remote-control mechanism for electrical switching devices, in particular for circuit-breakers, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type in such a way that it can be used for different sizes with different switching characteristics, taking the required safety measures into account, with minimal power consumption and a simple construction. 
     With the foregoing and other objects in view there is provided, in accordance with the invention, a motor-operated mechanism with a gearwheel transmission and snap-action closing for electrical switching devices, in particular circuit-breakers, having a twist knob for actuation, comprising a driven gearwheel having a first pin, a second pin and an attachment; a driver reaching through the driven gearwheel for mounting the driven gearwheel centrally through the knob onto the driver, the driver gripping over and establishing a connection with the knob for manual actuation and transferring a driving force; a supporting lever mounted on the driver like the driven gearwheel and leading the driver and the supporting lever to a latching location, at a beginning of a switching-on operation; a prestressed spring received by the driven gearwheel and having a movable end supported on the first pin and simultaneously engaging in the supporting lever, the spring having a prestressing force passing from the first pin to the supporting lever; a resilient driver; a lug; an adjustment-free snap-action system; first and second limit switches; and a geared motor; the driven gearwheel continuing to rotate alone, stressing the spring further, until the second pin releases the latching location, and transfers a switching-on torque of the spring to the driver, the driver switching the circuit-breaker on with snap action, and subsequently the driven gearwheel with the resilient driver being driven resiliently against the knob, until the attachment moves the lug actuating the adjustment-free snap-action system and in turn actuating the first limit switch initiating reversing operation of the geared motor and of the driven gearwheel, for returning the driven gearwheel, the spring and the supporting lever to a starting position until the second limit switch ends the switching-on operation and carries out a switching-off movement in a manner analogous to the switching-on movement without snap action. 
     A comparison reveals the following: 
     
       
         
               
               
               
             
           
               
                   
                   
               
               
                   
                 Motor-operated mechanism 
                   
               
               
                   
                 according to the invention 
                 Conventional apparatus 
               
               
                   
                   
               
             
             
               
                   
                 1 limit switch 
                 1 limit switch, cap 
               
               
                   
                   
                 1 limit switch, closing 
               
               
                   
                   
                 1 limit switch, electrical 
               
               
                   
                   
                 separation when there is 
               
               
                   
                   
                 mechanical separation 
               
               
                   
                   
               
             
          
         
       
     
     Other features which are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a remote-controlled mechanism with a motor for circuit-breakers, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic, plan view of a mechanism assembly with snap-action closing, in which an upper mounting plate is removed; 
     FIG. 2 is a plan view of a mechanism assembly without snap-action closing, in which the upper mounting plate is removed; 
     FIG. 3 is a side-elevational view of a mechanism assembly with snap-action closing; 
     FIG. 4 is a side-elevational view of a mechanism assembly without snap-action closing; 
     FIG. 5 is a bottom plan view of a mechanism assembly with and without snap-action closing (snap-action system); 
     FIG. 6 is a plan view of a mechanism assembly with an upper mounting plate (interlocking system); 
     FIG. 7 is a side-elevational view of a mechanism assembly with a frame and a circuit-breaker, in which a complete motor-operated mechanism with a circuit-breaker is represented; and 
     FIG. 8 is a side-elevational view illustrating the principle of snap-action closing (latch system). 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now in detail to the figures of the drawings, in which a functional sequence is described on the basis of representations made therein, and first, particularly, to FIGS. 1-5 thereof, there is seen a geared motor  15  on a pivot lever  26  having a gearwheel  27 , which can be pivoted out  20  of gearwheel engagement in the event of a fault for manual actuation with an eccentric  35  (distance a) having a pin  34 . The drive gearwheel  27  is mounted with the geared motor  15  on a first spacing bolt  28 . Another spring  29  is disposed between the pivoting lever  26  and a second spacing bolt  30  and acts on the pivoting lever  26  with a torque. The geared motor  15  drives a driven gearwheel  1  through a coupling gearwheel  31 . The driven gearwheel  1  is seated on a spindle (driver  4 ) with a circuit-breaker  3  to be switched that is seen in FIG. 7, which shows a complete motor-operated mechanism with the circuit-breaker  3 . A resilient stop  48  switches off the circuit-breaker  3 . The driver  4 , which is part of a mechanism assembly  17  or  18 , grips around a knob  2  of the circuit-breaker  3  and has a similar knob  25  with an interlocking mechanism  23  (lockable) for manual actuation and for indicating a switching position. The two actuating knobs  2 ,  25  are rigidly coupled to one another in a direction of rotation. The actuating knob  2  of the circuit-breaker  3 , which has internal snap-action closing, is turned by the driven gearwheel  1  about a loose and resilient coupling into a respectively desired switching direction ON or OFF. Once this circuit-breaker has reached its snap-action closing point, for example in the ON direction, it can switch on unhindered. The motor-operated mechanism continues to travel itself in this direction until a snap-action system  13  of the motor-operated mechanism shown in FIG. 5, that is actuated by attachments  11  on the driven gearwheel  1 , changes the rotational direction of the motor at a lug  12 . The snap-action system  13  actuates a first limit switch  14 . A further spring  45  is drawn after switching of the circuit-breaker  3  beyond dead center of a snap-action lever  46 . In this case, drivers  47  shown in FIG. 2 operate resiliently against the driver  4  and consequently against the knob  2 . The switching-on or switching-off position is reliably reached. This operation is all the more important in the case of free tripping of the circuit-breaker  3 , since reliable relatching requires this operation. 
     The driven gearwheel  1  is returned to a starting position by pole reversal of the motor  15  through limit switches  37  shown in FIGS. 4,  5 ,  7 , so that clearances  55  are again one above the other and a current or power setting  54  of the circuit-breaker  3  shown in FIGS. 1 and 2 is visible and operable, and manual switching is possible. Switching off is performed through the use of a second limit switch  16 . 
     The circuit-breaker  3  without snap-action closing (FIGS. 2 and 4) is actuated in a similar way, but the switching on is performed with the aid of a prestressed spring and a latch system shown in FIG.  8 . Adaptation to the circuit-breaker  3  without snap-action closing is achieved by simple and slight modification of the system or assembly  17  into the system or assembly  18 . 
     The driven gearwheel  1  has a torsion spring  5 ,  6  and a supporting lever  8  shown in FIGS. 1 and 8 and is moved up to a latching location  9 . At this point, a torque of the torsion spring  5  is transferred by a first pin  7  of the driven gearwheel  1  to the supporting lever  8 . The spring is stressed further by the geared motor. As this gearwheel  1  continues to move, a second pin  10  on the driven gearwheel  1  releases the latching. The torque of the spring  5  is then transferred to the driver  4  and consequently the circuit-breaker  3  with snap action is closed. 
     As the procedure continues, the torsion spring  5  then takes over a resilient overtravel for switching over the snap-action system according to FIGS.  5 . After switching over, the system moves back again to the starting position. The following applies for the torsion spring: 
     
       
         M torsion spring &gt;M circuit-breaker   
       
     
     Consequently, adaptation of the torques through the spring is possible. 
     In the starting position, to which the driven gearwheel  1  is returned after every execution of a command, the knob  25  of the motor-operated mechanism can at any time be switched over manually. In this case, the motor-operated mechanism is then automatically made to follow and consequently the condition of dominant OFF is satisfied. This is achieved by a limit switch  53 , which is actuated by a deformation  52  of a resetting lever  49  and is connected parallel to an ON button. In the event of a fault, i.e. a voltage failure, during a switching operation in the motor-operated mechanism, the geared motor  15  must be pivoted through the use of a tool disposed in a cap  39  for an actuation of a switching-over bolt  36  shown in FIG. 7 into a “manual” position for manual operation. It is only in this position that the cap  39  can be removed and the arresting and locking of the knob can be performed, as described. 
     The motor-operated mechanism also includes a button  24  with a screw  51  for resetting a pilot switch  50  for short-circuit tripping. In the supplied state, this resetting is performed automatically when switching off takes place or a RESET function is executed after tripping of the circuit-breaker. If the user does not want this, this automatic mechanism can be disabled by removing the screw  51  in the resetting button  24 . An electronic control for the sequence is accommodated on a circuit board  56 , which is fastened between mounting plates  20 ,  21 . A slide  41  can be pulled out of the knob  2  and engages in the upper mounting plate  20 . Through the use of the configuration according to the invention, adaptation to different circuit-breakers  3  with different switching characteristics is achieved with very low power consumption. The snap-action system being used operates without requiring any adjustment. 
     The circuit-breaker  3  is screwed onto a frame  19  shown in FIG.  7 . Individual parts of the mechanism assemblies  17 ,  18  are mounted between or on the mounting plates  20 ,  21  and are placed onto the knob  2  of the circuit-breaker  3 , screwed to the frame  19  and covered with the cap  39 . The remote-controlled mechanism is connected through a plug-in connector to supply voltages and control devices for the actuation. Adaptation to a number of sizes of circuit-breakers is performed by using different frames  19  in combination with different types of mechanism assemblies  17 ,  18 , with and without snap action. The basic construction is the same in this case and different mechanism assemblies are produced by exchanging or omitting just a few parts. FIG. 1 shows a plan view of a mechanism assembly with snap action. The gearwheel coupling  1 ,  27 ,  31  with the geared motor  15  can be seen in FIGS. 3 to  5  and  7 . A lateral basic construction is represented in FIG.  8 . This figure reveals the driver  4 , which serves as a bearing spindle of the driven gearwheel  1 , the supporting lever  8  and the knob  25  and is mounted between the mounting plates  20 ,  21 . 
     A latching system is formed by the torsion spring  5 , the pin  7  on the driven gearwheel  1  and a half-shaft  44 . The torsion spring  5  is mounted in a prestressed manner on the driven gearwheel  1  and supports itself on the pin  7 . 
     FIG. 2 shows a plan view of a mechanism assembly  17  without spring-action or snap-action closing. In comparison with the mechanism assembly  18 , the torsion spring  5 , the supporting lever  8  and the half-shaft  44  are omitted and the resilient driver  47  is added. The structure of the mechanism assemblies  17  and  18  is represented in FIGS. 3 and 4. The motor-operated mechanism is supplemented by a pivoting system having parts  26 ,  28 ,  29 ,  30 ,  32 ,  33  for mechanical decoupling of the gearwheels and electrical separation in manual operation, the snap-action system  12 ,  13  shown in FIG. 5 for switching over the motor (reversing operation) and the interlocking system  23  of a switching-over device  22  shown in FIG.  6 . In this case, the pivoting system and the interlocking system  23  are coupled to one another, in that locking of the knob  25  is possible only in the OFF position of the circuit-breaker  3  when there is mechanical and electrical separation of the motor-operated mechanism. 
     At the same time, the cap  39  has a hook  43  shown in FIG. 7 for connecting it to a locking bar  38  having an attachment  42 . Removal of the cap is possible only when there is mechanical and electrical separation of the device. This combination dispenses with limit switches. 
     The mechanism  18  with snap-action closing can be produced from the mechanism  17  without snap-action closing by a combination of the drive gearwheel  1  in connection with the supporting lever  8 , the half-shaft  44  shown in see FIG.  8  and the spring  5 .