Abstract:
A locking apparatus for a manual actuation device of a switchboard plant has a trigger mechanism that is activated by an absence of a backup or a defective backup, and a locking mechanism for the manual actuation device. The locking mechanism is coupled to the trigger mechanism and is transferable by the trigger mechanism from a first position releasing the manual actuation device into a second position locking the manual actuation device. The locking apparatus has a simple and cost-effective construction, it is proposed that the locking mechanism has a cover plate which is displaceable between two positions by the trigger mechanism and which, in its first position, blocks a lever configuration under tensile force, of the locking mechanism and, in its second position, releases the lever configuration in order to lock the manual actuation device.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the priority, under 35 U.S.C. §119(e), of provisional application No. 60/763,006, filed Jan. 27, 2006; the prior application is herewith incorporated by reference in its entirety. 

   BACKGROUND OF THE INVENTION 
   The invention relates to a locking apparatus for a manual actuation device for electrical switching equipment. The locking apparatus has a release mechanism that is activated as a result of an absence of a backup or a defective backup, and a locking mechanism for the manual actuation device. The locking mechanism is coupled to a release mechanism and is transferable by the release mechanism from a first position releasing the manual actuation device into a second position locking the manual actuation device. 
   Such an apparatus is known, for example, from U.S. Pat. No. 5,835,002. The locking apparatus disclosed there is provided for locking a hand-operated actuating lever as a manual actuation device for electrical switching equipment, and in this case the manual actuation device is to be locked after a backup of the electrical switching equipment has been triggered and is consequently defective or when a backup of the electrical switching equipment is absent. In these situations, the electrical switching equipment is to be prevented from being switched on by the manual actuation device. For this purpose, the locking apparatus contains a release mechanism, which is activated as a result of an absent or defective backup, and a locking mechanism, which is coupled to the release mechanism and is in a position releasing the manual actuation device as long as there is no absent or defective backup, and, in the case of the defective or absent backup, is transferred by the triggered trigger mechanism into a position locking the manual actuation device. 
   SUMMARY OF THE INVENTION 
   It is accordingly an object of the invention to provide a locking apparatus that overcomes the above-mentioned disadvantages of the prior art devices of this general type, which has a simple and cost-effective construction. 
   With the foregoing and other objects in view there is provided, in accordance with the invention, a locking apparatus for a manual actuation device for electrical switching equipment. The locking apparatus contains a trigger mechanism activated by an absence of a backup or a defective backup, and a locking mechanism for the manual actuation device having a lever configuration. The locking mechanism is coupled to the trigger mechanism and is transferable by the trigger mechanism from a first position releasing the manual actuation device into a second position locking the manual actuation device. The locking mechanism has a cover plate displaceable between the first and second positions by the trigger mechanism and, in the first position, the cover plate blocks the lever configuration, under tensile force, of the locking mechanism and, in the second position, the locking mechanism releases the lever configuration to lock the manual actuation device. 
   The object is achieved, according to the invention, in that the locking mechanism contains a cover plate which is displaceable between two positions by the trigger mechanism and which, in its first position, blocks a lever configuration, under tensile force, of the locking mechanism and, in its second position, releases the lever configuration for locking the manual actuation device. 
   Such a cover plate constitutes a simple measure for blocking and releasing the lever configuration of the locking mechanism and advantageously leads to a simple and therefore cost-effective configuration. 
   In an advantageous refinement, the lever configuration contains a trigger lever which is mounted rotatably on a bearing arm and the first end of which is coupled to a housing of the electrical switching equipment via a tension spring and the second end of which is connected in an articulated manner to a rotatably mounted locking lever. A configuration of this type affords a simple possibility of configuring a lever configuration triggerable by the cover plate. 
   In a further refinement of the invention, a stop element for engagement into a clearance of the cover plate in its second position is provided on the trigger lever. By such a stop element, the cover plate of the lever configuration is blocked in a simple way, and, with the trigger mechanism triggered and with the cover plate in its second position, the lever configuration is released as a result of the engagement of the stop element into the clearance, with the result that the manual actuation device is locked in a simple way. 
   In a further refinement of the invention, the locking lever has a free end with a sliding face pointing in the direction of the switched-on position of the manual actuation device and an extension pointing in the direction of the switched-off position of the manual actuation device. By such a configuration of the free end of the locking lever, it is possible in a simple way for the electrical switching equipment to be switched off by the manual actuation device, even in the locked position, because the manual actuation device can slide along the sliding face and can deflect the rotatably mounted locking lever out of the locking position, and, on the other hand, with the electrical switching equipment switched off and with the locking mechanism triggered, the extension reliably prevents the electrical switching equipment from being switched on by the manual actuation device. 
   In an expedient development, the locking mechanism contains a manual return mechanism coupled to the trigger lever and has a hand-operated actuating lever. By a manual return mechanism of this type, it is advantageously possible, after the replacement of defective backups, to transfer the locking mechanism by hand into its position releasing the manual actuation device of the electrical switching equipment. 
   In an advantageous refinement of the invention, the cover plate is coupled to the trigger mechanism via a sliding linkage and joints. Advantageously, in a configuration of this type with a sliding linkage, the dead weight of the sliding linkage or an additional spring mechanism is utilized in order to hold the trigger mechanism in its non-triggering position, with a functioning backup being engaged. 
   In a further refinement, the trigger mechanism contains a rocker lever which is connected in an articulated manner to the sliding linkage and which is disposed rotatably in a backup housing end part and extends into the backup housing end part and beyond a backup. Backups for electrical switching equipment of this type have, in a known way, a trigger pin which, in the case of a functioning backup, is located in the backup and, in the case of a defective backup, projects out of the latter. The configuration with a rocker lever is suitable in a simple way for bringing about a rotation of the rocker lever about its rotary bearing by the trigger pin, acting directly on the rocker lever, of a defective backup, and, via the articulated connection, for pushing the cover plate of the locking mechanism into its position releasing the lever configuration. 
   In a further development of the invention, the trigger mechanism contains a folding plate that can be moved between a folded-in position and a folded-out position by a clip mechanism of the backup and tension spring elements of the trigger mechanism. A folding plate of this type affords a simple possibility, in the absence of a backup, for holding the rocker lever in the triggered position, until the folding plate is folded back into its second position by a backup via the clip mechanism and the rocker lever is transferred into its non-triggered position due to the dead weight of the sliding linkage. 
   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 locking apparatus, 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, rear view of a locking apparatus according to the invention in a non-locking position; 
       FIG. 2  is a diagrammatic, side view of the locking apparatus shown in  FIG. 1 ; 
       FIG. 3  is a diagrammatic, cross-sectional view of a trigger mechanism of the locking apparatus according to the invention; 
       FIG. 4  is a diagrammatic illustration of a functioning backup and a defective backup; 
       FIG. 5  is a diagrammatic, cross-sectional view of the trigger mechanism of the locking apparatus according to the invention in a triggered position; 
       FIG. 6  is a diagrammatic, rear view of a locking mechanism of the locking apparatus according to the invention in a locking position; and 
       FIG. 7  is diagrammatic, side view of the locking mechanism shown in  FIG. 6 . 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the figures of the drawing in detail and first, particularly, to  FIG. 1  thereof, there is shown a cross-sectional view of an electrical switching apparatus or equipment  1  with a housing part  2 , in which is provided an opening slot  3 , into which a switch lever  4  can be inserted in order to switch the electrical switching equipment  1  on and off. The switch lever  4  serves for closing and opening non-illustrated contact systems of the respective phases of the electrical switching equipment  1 , moving contacts of the contact systems being connected to and separated from fixed contacts of the contact systems by the switch lever  4  and a non-illustrated switch shaft. In the illustration represented by unbroken lines, the switch lever  4  is in a position between a current-carrying position  5 , illustrated by dashes, of the electrical switching equipment  1  with closed contact systems and the switched-off position  6 , illustrated by dashes and dots, of the electrical switching equipment  1  with separated contact systems. To lock the switch lever  4  in order to prevent a movement of the switch lever  4  into the current-carrying position  5  when a backup is defective or absent (e.g. fuse, breaker, etc.), a locking mechanism  7  is provided. The locking mechanism  7  contains a locking lever  8 , a free end  9  of which has a sliding face  10  on a side facing the current-carrying position  5  and an extension  11  on a side facing the switched-off position  6 . The locking lever  8  is mounted rotatably on a first bearing  12  and, at its end  13  located opposite the free end  9 , is connected in an articulated manner to a trigger lever  14  by an articulated connection  15 . The trigger lever  14  has a stop element  17  pointing in a direction of a displaceable cover plate  16  and is likewise mounted rotatably on a second bearing  18 . At an end  19  located opposite the articulated connection  15 , the trigger lever  14  is connected to a tension spring  20  that is fastened to the housing part  2  of the electrical switching equipment  1  at a fastening element  21 . The second bearing  18  of the trigger lever  14  is disposed on a bearing arm  22  of the housing part  2 . A movable return mechanism  23 , when it moves in the direction of the trigger lever  14 , acts against the end  19  of the trigger lever  14 . 
     FIG. 2  illustrates a front view of the locking mechanism  7 . A hand-operated actuating mechanism  24  is provided for actuating the manual return mechanism  23  for the locking mechanism  7 . A movable cover plate  16  has a clearance  25  that is provided for the engagement of the stop element  17  of the locking lever  8  in a triggering position. At its lower end  26 , the cover plate  16  is connected mechanically to a sliding linkage  27 . The sliding linkage  27  is coupled to a trigger mechanism  28 , not illustrated in  FIG. 2 . 
     FIG. 3  shows a cross-sectional view of the trigger mechanism  28 . The sliding linkage  27  is coupled to the trigger mechanism  28  via joints  29  and a further sliding rod  30 , in that the sliding rod  30  transmits sliding movement to a rocker lever  32  by a joint  31 . The rocker lever  32  is mounted rotatably in a bearing hole  33  of a housing  34  of the trigger mechanism  28  and extends through an interior wall of the housing  34  as far as a clearance of a guide part  37  that is provided for limiting the movement of the rocker lever  32 . Inside the housing  34 , the rocker lever  32  extends through the guide part  37  that limits a clockwise movement of the rocker lever  32 . Below the rocker lever  32  which is in a horizontal position is disposed a folding plate  38  which is connected to a clip mechanism  39  and tension springs  40 ,  41 . The position of the trigger mechanism  28  of  FIG. 3  is a position, with a backup  42  engaged and functioning. 
   The trigger mechanism  28  disposed underneath the locking mechanism  7  is held in the position of  FIG. 3  via the dead weight of the sliding linkage  27  or by a non-illustrated spring mechanism as long as the backup  42  is engaged and functioning, that is to say, in particular, with a trigger pin not projecting. 
     FIG. 4  shows diagrammatically a functioning backup  42 , with a trigger pin  43  not projecting, and a defective backup  44 , with a trigger pin  45  projecting. 
   The trigger mechanism  28  and the functioning of the locking apparatus are described in more detail below with reference to  FIGS. 5 ,  6  and  7 . 
     FIG. 5  shows the trigger mechanism  28  of  FIG. 3  in a position in which the backup  42  is absent. The folding plate  38  acts as a blocking element on the rocker lever  32  counter to the force acting in the opposite direction on the rocker lever  32  owing to the dead weight of the sliding linkage  27  or to the spring mechanism. Due to the force exerted directly on the rocker lever  32  by the trigger pin  45  and the defective backup  44 , the rocker lever  32  is rotated clockwise about its bearing in the bearing hole  33  and is located in the position of  FIG. 5 , the rotation of the rocker lever  32  being limited by the guide part  37 . As a result of the clockwise movement of the rocker lever  32  about the bearing hole  33 , the sliding rod  30  is induced via the joint  31  to a downward movement and the sliding linkage  27  is induced via the joints  29  to a sliding movement that acts on the end  26  of the cover plate  16 . When the defective backup is removed, the folding plate  38  is folded into the position illustrated in  FIG. 5  by the tensile force of the springs  40 ,  41 . The folding plate  38  remains in this position until a new backup is engaged, the folding plate  38  being folded back into the position illustrated in  FIG. 3  by the clip mechanism  39 . 
     FIGS. 6 and 7  show the locking apparatus in a locked state that is reached by a triggered backup. As described with reference to  FIG. 5 , a triggered backup causes a movement of the sliding linkage  27 , with the result that the cover plate  16  is displaced in such a way that the clearance  25  of the cover plate  16  releases the stop element  17  of the locking lever  8 . In the position of  FIG. 6 , the stop element  17  passes through the clearance  25  of the cover plate  16 . When the stop element  17  comes into the region of the clearance  25  during the movement of the cover plate  16 , a force acting on the trigger lever  14  via the tension spring  20  brings about a clockwise rotation of the trigger lever  14  about the second bearing  18 , with the result that the locking lever  8  is induced to a counterclockwise rotation about the first bearing  12 . The locking lever  8  assumes a position in which the opening slot  3  of the housing part  2  is blocked for movement of the switch lever  4  in the direction of the current-carrying position  5  by the extension  11  of the locking lever  8 . When the switch lever  4  is in the current-carrying position  5 , a switch-off operation can be carried out via the sliding face  10  of the locking lever  8 , since, in the event of a movement of the switch lever  4  out of the current-carrying position  5  into the switched-off position  6 , the switch lever  4  slides along the sliding face  10  and at the same time induces the rotatably mounted locking lever  8  to a clockwise movement, with the result that the locking lever  8  releases the opening slot  3  until the switch lever has moved under the free end  9  of the locking lever  8 . In this position, via the force acting on the locking lever  8  by the tension spring  20  and the trigger lever  14 , the locking lever  8  is again induced to a counterclockwise movement, so that it subsequently blocks the opening slot  3  again. A movement out of the lower switched-off position  6  into the current-carrying position  5  is prevented by the extension  11  of the locking lever  8 . 
   A release of the lock by the locking lever  8  for the switch lever  4  is possible by the hand-operated actuating mechanism  24  and the return mechanism  23 , in that, via the hand-operated actuating mechanism  24 , the return mechanism  23  acts, during movement in the direction of the trigger lever  14 , against the end  19  of the trigger lever  14  and induces the latter to a counterclockwise rotation, with the result that the locking lever  8  moves clockwise and releases the opening slot  3  again for a movement of the shift lever  4 . In this case, the engagement of the stop element  17  into the clearance  25  and the cover plate  16  is cancelled. If, furthermore, a new backup, with the trigger pin not projecting, is engaged into the housing  34  of the trigger mechanism  28 , then the clip mechanism  39  causes the folding plate  38  to be folded back into a horizontal position, so that, via the dead weight of the sliding linkage  27 , the cover plate  16  is moved downward and, via the sliding linkage  27 , the joints  29  and the sliding rod  30 , the rocker lever  32  is rotated back into its horizontal position. 
   If, however, no new backup has been engaged into the housing  34  of the trigger mechanism  28 , then the folding plate  38  remains in its folded-out position and prevents the rocker lever  32  from being rotated back into the horizontal position, even in the event of a manual actuation of the hand-operated actuating mechanism  24 , since the movement of the cover plate  16  via the sliding linkage  27  and the sliding rod  30  is prevented and blocked due to the blocking of the rocker lever  32  by the folding plate  38 . 
   Thus, by the locking apparatus, on the one hand, in the event of defective backup, with a trigger pin projecting, a switching operation of the electrical switching equipment by the shift lever  4  from the switched-off position  6  to the current-carrying position  5  is prevented, as described with reference to  FIG. 6 , and, on the other hand, a release of the locking apparatus of the opening slot  3  for a movement of the switch lever  4  out of the switched-off position  6  into the current-carrying position  5  is prevented even when no new functioning backup has been engaged into the housing  34 .