Abstract:
An actuating unit or actuating mechanism and release for a circuit breaker. The magnetic mechanism of the release includes a magnet armature, which can move linearly in a magnet coil, is in the form of a tripping plunger and can be moved towards a permanent magnet counter to the force of a storage compression spring and is held fixedly by said permanent magnet in the case of a magnet coil through which no current is flowing. The tripping unit is in the form of a mechanical force store. After a tripping action, the mechanical force store needs to be reset manually again. For this purpose, a rotary movement of the drive shaft with an angular displacement of from 20 to 30 degrees takes place in the opposite direction to the ON switching rotary movement.

Description:
The invention relates to an electrical circuit breaker with a protective function in case of a fault. Such circuit breakers comprise a switch mechanism, current paths with disconnectable contacts, an electromagnetic tripping unit, an electromagnetic control module that regulates in case of a fault, and a manual actuator unit for switching on and off as well as for resetting the tripping unit after it has been tripped. In response to a switch-OFF command, the tripping unit acts mechanically on the switch mechanism (for purposes of opening a biased latch or the contacts). 
   BACKGROUND 
   Circuit breakers of this type can be configured as motor circuit breakers or as automatic circuit breakers that are employed to switch a load on and off and that have a protective function by separating or interrupting the load in case of an electrical fault. Electrical faults can be short circuits, overcurrents or else undervoltages. Examples of typical circuit breakers are also residual current circuit breakers (for instance, German patent application DE 4106652 A1) which, however, cannot be utilized to switch loads on and off. 
   An example of a circuit breaker of the generic type is presented in German patent application DE 198 36 549 A1. The tripping unit can be of the conventional type, for instance, like the one described in GB 1,558,785. Here, the magnetic mechanism consists of a solenoid armature which can move linearly in a solenoid coil and which is configured as a tripping tappet that can be moved towards a permanent magnet against the force of a pressure spring by means of which it is held in place when the solenoid coil is de-energized. 
   In the case of many circuit breakers, the space available for the installation of a tripping unit is small. In view of the low voltage level, this is an economical solution for use in the automotive sector (German patent specification DE 197 41 919 C1). However, for low-voltage applications, higher requirements in terms of insulation and higher switching capacities have to be achieved. 
   SUMMARY OF THE INVENTION 
   An object of the present invention is to provide a particularly compact configuration of an actuator unit or actuator mechanism and of a tripping device for a circuit breaker. 
   The present invention provides an actuator unit configured as a rotating mechanism having a drive shaft which is operatively connected to the switch mechanism for switching on and off, and between the drive shaft and the tripping unit, a mechanical operative connection by means of which the magnetic mechanism of the tripping unit is reset when the drive shaft is moved out of its OFF position in the direction opposite from the rotational movement for switching on. 
   The switch concept is the principle of the energetically self-supplied tripping concept. In other words, the tripping unit is without power supply when it is in the activated position and, with a relatively small current surge, it is capable of triggering the latch so as to open the contacts. In order to achieve this task, the tripping unit is configured as an energy storage mechanism. Following a tripping action, the energy storage mechanism has to be manually reset. The circuit breaker cannot be moved from its OFF position into the ON position if the tripping unit has not been previously reset. 
   It is proposed for the resetting movement of the tripping unit to be executed by the rotational movement of the drive shaft at an angular displacement of 20° to 30° in the direction opposite from the rotational movement for switching on. According to the invention, the operative connection between the actuator unit and the tripping lever that constitutes the tripping unit is a double-arm lever whose first arm is acted upon by at least one catch means on the drive shaft and whose second arm brings about the resetting movement of the tripping unit. 
   With the application of deformation work by the pressure spring, the second arm moves the solenoid armature of the energy storage mechanism over to the permanent magnet, whereby the solenoid armature (tripping tappet) is held in place by the holding force of the permanent magnet. 
   The tripping takes place due to a current surge through a magnetic circuit whose generated magnetic flux overcomes the holding force of the permanent magnet. As a result of the movement of the solenoid armature into the tripped position, the switch mechanism and the drive shaft are mechanically moved, whereby the latch is actuated and the switch mechanism opens and the drive shaft executes a rotational movement (into the OFF position). 
   The inventive arrangement can be used both as a single-pole circuit breaker and as a multi-pole circuit breaker. 
   The mechanical actuator unit can be arranged on the top of a circuit breaker, as a result of which the size of the circuit breaker only increases in terms of height (vertically); no changes occur in the horizontal extension (in terms of the installation dimensions). 
   The geometry of the involved manual actuator unit and its association with the tripping unit are configured in such a way that the double-arm lever is mounted axially parallel to the drive shaft (actuating shaft) and the solenoid armature is mounted perpendicular to the double-arm lever. In this context, a mechanical operative connection is created between the drive shaft and the magnetic mechanism in such a way that a rotation of the drive shaft is converted into a counter-rotation of the double-arm lever and the rotation of the double-arm lever becomes a linear movement of the solenoid armature. When the drive shaft is rotated by about 25° for the resetting movement, the solenoid armature moves by about 2.5 mm. The mechanical design is such that the second arm of the double-arm lever is configured as a prong and the solenoid armature is provided with a groove so as to engage with the prong. 
   The drive shaft is created by assembling an actuating shaft and a receiving shaft. This is comprehensively explained in the description of the figures. 
   A preferably colored marking can be placed on one arm of the double-arm lever. Here, a window is provided in the housing of the circuit breaker in such a way that the marking can be seen through the window from the outside when the tripping unit is either in the reset position or in the tripped position. This allows a user to directly see whether the circuit breaker circuit breaker can be switched on, without resetting, or whether the tripping unit still has to be reset before the circuit breaker can be switched on. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     An embodiment of the invention is presented in the figures, which show the following in greater detail: 
     FIG.  1 —individual parts in an exploded view; 
     FIG.  2 —the assembly of the drive shaft; 
     FIG.  3 —a horizontal section through the arrangement; and 
     FIG.  4 —the tripping unit with the double-arm lever and driveshaft. 
   

   DETAILED DESCRIPTION 
   The actuating button  42  configured as a knob is affixed at the end of a drive shaft  40  included in the actuator unit  140  and it extends beyond the housing (not shown here) of the circuit breaker. The drive shaft  40  is a multi-component assembly consisting of the actuating shaft  44  and the receiving shaft  60 . This assembly is shown and described separately and comprehensively in  FIG. 2 . 
   From the outside, all that can be seen of the circuit breaker is the knob  42  that can be in an OFF position and in an ON position, which are offset from each other by 90°. In the ON position, the contacts are closed and the tripping unit can be activated. From this position, the contacts of the circuit breaker can be manually opened by turning the drive shaft  40  counterclockwise D 1  by means of the knob  42 . The drive shaft releases the latch in the switch mechanism and opens the contacts. For the manual switch-OFF, a brief rotation in the D 1  direction is sufficient in order to actuate the latch. Rotation by a full 90° is not necessary for this purpose. When the circuit breaker is automatically switched off in case of a fault and the contacts are opened, the drive shaft  40  is automatically moved along as well. 
   In the switched-off state of the circuit breaker (latch/contacts open), it is not possible to directly move the circuit breaker into the switched-on state. The tripping unit  10  works as an energy storage mechanism and first has to be biased. The tripping unit  10  has a pot-shaped magnetic circuit and it works with the holding force of the permanent magnet. One end of the solenoid armature  14  that can be moved in the magnetic circuit interacts magnetically with a permanent magnet  16  while the other end is configured as a tripping tappet. The solenoid armature  14  is acted upon by a pressure spring  17 . 
   The axis HA of the actuating shaft is very close to the housing  11  of the tripping unit  10  (also see  FIGS. 3 and 4 ). The double-arm lever  30  is mounted axially parallel to the actuating shaft  44  and the solenoid armature  14  is mounted perpendicular to the double-arm lever  30 . 
   The tripping unit is activated by manually turning the knob  42  (of the drive shaft  40 ) counterclockwise D 1  around the axis HA of the drive shaft  40  out of the OFF position by about 20° to 30°, in other words, in the direction opposite from the movement for switching on. By means of this manual actuation, the energy storage mechanism is moved into the switched-on position. When the knob  42  is turned in the direction (D 1 ) counter to the movement for switching on, two catch lugs  61 ′,  61 ″ engage operatively with the first arm  32  of the tripping lever  30  configured as a double-arm lever. The rotation of the actuating shaft is converted into a rotation of the double-arm lever in the opposite direction (reference numerals H 1 , H 2 ). This actuation follows the action chain consisting of the knob  42 , the drive shaft  40 , the catch lugs  61 ′,  61 ″, the double-arm lever  30 , the prong  35 , the solenoid armature  14  and the permanent magnet  16 . The solenoid armature  14  is moved over to the permanent magnet, where it is held in place magnetically. 
   It has already been mentioned that the latch cannot be switched on without actuating the power drive. The latch is locked and released by a locking pawl  80  biased by a return spring. This locking pawl  80  is mounted in the circuit breaker as a double-arm lever so that it can rotate around an axis KA. When the tripping unit is biased, a catch element  36  on the lower end of the double-arm lever actuates the locking pawl  80  against the force of the return spring. A cap  82  that is acted on by the catch element  36  is present on the upper lever arm on the locking pawl  80 . After the tripping unit has been biased, the double-arm lever, together with the catch element  36 , is in a fixed position, whereby the locking pawl  80  is pried out of its resting position. In this position, the second lever arm  84  of the locking pawl interacts with the latch in such a way that the latter can be moved into the ON position. 
   The tripping (faulty opening by the electromagnetic control module, possibly in conjunction with an electronic module that is not described in greater detail here) takes place when a sufficiently high current is present in the winding of the tripping coil  12 . The magnetic attraction exerted by the permanent magnet  16  is weakened and the solenoid armature  14 , assisted by the force of the pressure spring, is released (executing movement L 2 ). 
   The solenoid armature and the double-arm lever  30  are in positive operative connection via the groove  15  on the tripping tappet and on the prong  35  on the double-arm lever, so that the movement of the solenoid armature is always transmitted to the double-arm lever  30 . The linear displacement of the solenoid armature amounts to a few millimeters. The rotational movement (H 1 , H 2 ) associated with the linear movement (L 1 , L 2 ) of the double-arm lever  30  is about 25° to 30°. Below the plane of the drawing, a catch means  36  is arranged on the double-arm lever  30  and said catch element  36  interacts with the locking pawl  80  of the latch (opening of the contacts). 
   The contact system is made to open by the movement L 2  of the solenoid armature  14  over the latch. 
   The drive shaft  40  is in positive operative connection with the latch via a coaxial plug-in connector having catch means (not shown here). The movement of the drive shaft  40  via the drive axis  115  causes the actuation of the latch in both directions of rotation (for ON and OFF). 
   The tripping unit  10  is accommodated in a plastic housing  11  where essentially the solenoid coil  12  is mounted. The housing  11  is arranged on the top  110  of the circuit breaker, whereby in the embodiment shown, the housing is attached by means of at least one attachment means (screws, connectors or clamps) (here a placement cylinder  19 ) to mating means (here openings  119  on the top  110 ). Line AA in the figure shows the spatial association of the placement cylinder  19  with the opening  119 . 
   According to the embodiment, the main axis MA of the tripping unit  10  and thus also the axis of the solenoid armature  14  configured as a tripping tappet is horizontal. The drive shaft  40  has a perpendicular position in the circuit breaker. Therefore, the longitudinal axis of the solenoid armature is at 90° relative to the drive shaft  40 . 
   A bearing SS for the double-arm lever  30  is present on the housing of the tripping unit parallel to the axis HA of the drive shaft  40 . The double-arm lever  30  is pivotably attached in the bearing SS by means of the pin  20 . 
   The embodiment in  FIG. 2  shows that the drive shaft  40  is made up of two parts by mounting an actuating shaft  44  onto a receiving shaft  60 . The knob  42 , the actuating shaft  44 , the receiving shaft  60  and the switch mechanism (indicated by the axis journal  115  in the figure) lie on a shared axis. The lower region of the receiving shaft  60  is hollow and its upper region has a journal to receive the knob. A catch bar  62  and two catch lugs  61 ′,  61 ″ are configured on the receiving shaft so as to be opposite from each other by about 180°. After the assembly, the catch bar  62  engages with the actuating shaft  44  in a catch segment  45  configured there. The edge of the catch bar  62  situated on the front during a clockwise rotation (movement for switching on) lies against the stop in the catch segment  45 . Therefore, the actuating shaft  44  is directly carried along during the movement for switching on. 
   The edge of the catch bar  62  situated on the front during a counterclockwise rotation is the catch means (stop in the catch segment  45 ) for the manual switching off, whereby a displacement of the torsion spring  67  of about 30° is first overcome, until the actuating shaft  44  is carried along. Thus, a certain amount of play exists between the receiving shaft  60  and the actuating shaft  44 , which leaves the actuating shaft  44  disengaged when the receiving shaft  60  executes the resetting movement D 1 . 
   The above-mentioned torsion spring  67  is placed between both shafts ( 44 ,  60 ) and after the tripping unit has been biased, this spring serves to reset the receiving shaft vis-à-vis the actuating shaft and moves the drive shaft and especially the knob into an unambiguous OFF position. The end  67 ′ of the spring wire of the torsion spring  67  is bent outwards and lies against the catch bar  62 . The second end  67 ″ (not visible in  FIG. 2 , shown in  FIG. 4 ) of the torsion spring  67  is bent inwards and takes hold in an axially parallel groove  44 ′ of the actuating shaft  44 . This upper end of the actuating shaft  44  has a journal that comes to lie in the hollow space of the receiving shaft  60  and, on the lower end, it has a bore for placement onto and attachment to the drive axis  115  of the circuit breaker.  FIG. 3  also shows how the catch bar  62  takes hold of the catch segment  45 . This catch segment  45  has a free circle segment angle of approximately 50°; the catch bar  62  can move freely between the stops of the catch segment by about 30° (spring displacement of the torsion spring  67 ). This corresponds to the angular displacement that is used by the biasing movement for the tripping unit. 
   In order to optimally utilize the space available, the distance of the individual parts with respect to each other is selected so as to be particularly small. The housing of the tripping unit is located especially close to the actuating shaft. This is why two catch lugs are installed on the actuating shaft (receiving shaft  60 ); a catch lug  61 ′ can graze above the tripping device housing and a catch lug  61 ″ can graze below the tripping device housing. 
   The receiving shaft  60  establishes an operative connection with the first arm  32  of the double-arm lever  30 . The second arm  34 ,  35  of the double-arm lever  30  is in close operative connection with the solenoid armature  14 . In the embodiment shown, this is realized in that the second arm  34  of the double-arm lever  30  is configured as a prong  35  and the tappet-like or bolt-like solenoid armature  14  has a groove  15  on its outer end. The prong  35  of the second arm  34  of the double-arm lever fits positively into the groove of the solenoid armature. 
   With each linear movement L 1 , L 2  of the solenoid armature  14 , the second arm  34  of the double-arm lever is carried along and causes the double-arm to rotate. There is no play in this positive operative connection. The movement of the solenoid armature  14  causes the double-arm lever to rotate and vice versa: the rotation of the double-arm lever causes the solenoid armature to move. 
   According to the invention, the mechanical operative connection between the solenoid armature  14  and the latch and the mechanical operative connection between the actuating shaft  44  and the solenoid armature  14  are brought about by a receiving shaft  60  suitably configured for both functions. 
     FIG. 3  shows a horizontal section through the arrangement. The drive shaft  40  is in the OFF position. This figure clearly shows the good utilization of space of the arrangement. The drive shaft is in the OFF position of the circuit breaker. 
   The actuating motions or the rotational movements will be listed here one more time.
         In the “manual switching on” function, the drive shaft  40  is moved out of the OFF position in the direction D 2  by being rotated clockwise by 90°, whereby the double-arm lever executes the movement H 2 . In this process, the armature moves linearly with L 1 .   In the “manual switching off” function, the drive shaft  40  is moved out of the ON position in the direction D 1  by being rotated counterclockwise by 90°, whereby the double-arm lever executes the movement H 1 . In this process, the armature moves linearly with L 2 .   In the “tripping unit biasing” function, the drive shaft  40  is moved out of the OFF position in the direction D 1  by being rotated counterclockwise by 25°, whereby the double-arm lever executes the movement H 1 . In this process, the armature is not moved along.       

   The latter rotational movement can be seen in  FIG. 3  on the basis of the two positions of the catch element  61 ′. In the position shown with the broken line, the receiving shaft  60  with the catch element  61 ′ is held in the resting position by the torsion spring. The position shown with the solid line is one in which the catch element  61 ′ has actuated the double-arm lever  30  (after the rotation D 1 ) and has moved the solenoid armature over to the permanent magnet (with the movement L 1 ). 
     FIG. 4  shows a view of the tripping unit similar to that of  FIG. 3 , as well as the double-arm lever and the drive shaft  40 . The double-arm lever  30  is shown here in both of its end positions. The drive shaft  40  is in the ON position of the circuit breaker and thus rotated clockwise by 90° relative to the position in  FIG. 3 . The two biased positions of the torsion springs  67  can be seen here. Since the catch bar  62  (not shown here, see  FIG. 2 ) is carried along, the first end  67 ′ of the torsion spring has been moved from a position indicated by a broken line into a position indicated by a solid line. Likewise visible is the groove  44 ′ of the actuating shaft (also see  FIG. 2  here). The second end  67 ″ of the torsion spring  67  lies in this groove. 
     FIG. 4  additionally shows a design possibility for purposes of rendering the position of the double-arm lever visible. A colored marking  35 ′ can be placed on one arm  34  of the double-arm lever  30 . Since the double-arm lever is in a rigid relationship relative to the solenoid armature, this marling can be employed to indicate whether the tripping unit is in the reset position. According to  FIG. 4 , the marking is present on the tripping device side ( 34 ) of the double-arm lever  30 . The double-arm lever is depicted in two positions (shown by a broken line and by a solid line). A window F is arranged in the housing (not shown here) of the circuit breaker above the position of the arm  34  of the double-arm lever  30 . Depending on the envisaged function, a green or red marking  35 ′ can be provided. The marking is either visible or not visible, depending on the position of the double-arm lever  30 . Therefore, either the tripped position (red marking) or the reset position (green marking) of the tripping unit can be made visible in the window from the outside by means of the marking  35 ′. Consequently, the user can immediately see whether the circuit breaker can be switched on, without resetting, or whether the tripping unit still has to be reset before the circuit breaker can be switched on.