Abstract:
A vacuum contactor includes a stationary contact and a moving contact, which can be moved in order to produce a current-carrying connection. In order to guide the moving contact during its movement in the enclosure, at least one guide element, which can be moved in a groove, is provided on the moving contact.

Description:
This application is the national phase under 35 U.S.C. §371 of PCT International Application No. PCT/DE00/04175 which has an International filing date of Nov. 24, 2000, which designated the United States of America, and which claimed priority on German Application No. 199 59 207.1 filed Dec. 8, 1999, the entire contents of which are hereby incorporated by reference. 
     FIELD OF THE INVENTION 
     The invention generally relates to a switching device which is in the form of a vacuum contactor. More preferably, it relates to one which includes a contact (stationary contact for example) which is fixed to the enclosure, and a contact (loose bearing for example) which can be moved in order to produce a current-carrying connection. 
     BACKGROUND OF THE INVENTION 
     Vacuum contactors are known as prior art, in which a sleeve is fitted on the loose bearing, and which slide on a pin which is fixed to the enclosure. Furthermore, vacuum contactors are known in which a guide ring is provided on the vacuum interrupter. 
     In this configuration, the interrupter bolt which produces the contact slides into this ring. The guide ring can in this case be arranged on the stationary side or on the loose bearing side. 
     EP 0 641 001 A1 discloses a switch having a vacuum interrupter, in which a contact support, which can be moved by a drive, of a moving switching element is held on an interrupter axis in a vacuum tight manner via a folding bellows and via a sliding guide, and is passed out of the switch enclosure. 
     The described switch has a guide groove  22  which is held in an integral bush  12 , which in turn merges into a mounting flange  13 . This is attached via screw connections  15  to a flange  16  of the enclosure  7  of the switch. In order to remove the moving contact support  8  of the switch, the screw connections  15  must be undone, and the mounting flange  13  must be pulled off the enclosure  7 . 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention is based on an object of offering a vacuum contactor with a moving contact guide such as a loose bearing guide, which is more convenient to operate. 
     Contactors are switching devices and are used, for example, for switching motors. The contactors may be in the form of air contactors or vacuum contactors. 
     The vacuum switching device, vacuum contactor for short, according to an embodiment of the invention for opening and closing circuits, has movable contact such as a loose bearing for example, with at least one guide element which is guided in a groove (recess) in the enclosure of the vacuum contactor and is moved during operation of the loose bearing. The loose bearing is in this way held and guided in the enclosure with a high level of repeatability accuracy and such that it is resistant to disturbances and faults. 
     In this case, the guide element can be fitted on a spring mount of a compression spring for producing additional contact pressure from the loose bearing on the stationary contact, as a result of which the spring mount has two functions. 
     If the guide element is fitted on an annular element which is arranged adjacent to the bellows element, and is thus fitted close to the contact point of the loose bearing, this results in the loose bearing being guided in a particularly reliable manner. 
     In order to further improve the guidance characteristics of the loose bearing, a number of, for example opposite, guide elements may also be provided on the spring mount and/or on an annular element. A simplified design configuration of the vacuum contactor is achieved if the annular element has not only a guide element fitted to it, but also an indicator for indicating the movement position of the loose bearing (closed/open) and/or a projection for positioning of an angled element for fitting a flexible strip on the loose bearing. 
     Guide elements which are essentially cuboid can be produced at low cost. In principle, the geometry of the guide element and of the corresponding groove (guide groove) for producing an interlock are matched to one another, and their cross sections can be matched to the respectively required load profile and may, for example, also be triangular or semicircular. 
     In this case, the term groove is intended to mean a recess of any type. The groove or grooves for holding the guide element or guide elements may be produced, for example, as molded recesses/depressions in the enclosure of the vacuum contactor or as recesses/depressions produced in some other way by forming, material cutting or material compressing manufacturing methods. 
     According to an embodiment of the invention, the groove for holding the guide element is formed by the interaction of the (fitted) cover of the enclosure with the lower part of the enclosure, so that when the enclosure is open and the cover is removed, the loose bearing can be removed conveniently from the enclosure (from above), for example for repair or for replacement of the vacuum interrupter. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Further details of the invention will become evident from the exemplary embodiments in the FIGS. of the drawings, in which: 
     FIG. 1 shows a perspective overall view of a vacuum contactor (interrupter assembly, current path) without an enclosure, 
     FIG. 2 shows a longitudinal section through the vacuum contactor shown in FIG. 1, with the surrounding enclosure, and 
     FIG. 3 shows a section B—B as shown in FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     When actuating three-phase motors, the individual phases are connected and disconnected separately, and the associated vacuum interrupters which are used for this purpose are normally located in enclosures with enclosure chambers arranged adjacent to one another, for holding the individual vacuum interrupters. 
     In this case, a single interrupter assembly is accommodated in each enclosure chamber, as shown in FIG.  1 . The interrupter assembly shown in FIG. 1 has a stationary bearing  33  with a stationary contact  1  fitted to it, as shown in FIG.  2 . 
     The interrupter  15  is fitted to the stationary bearing  33  and the bolt  16  of the loose bearing  2  (see FIG. 2) is located in it. The interrupter  15  with the bellows element  3  is followed by the annular element  9  with an indicator  10 , the angled element  28  and the compression spring  8 , which is held in the spring mount  7 . The lever  23  as shown in FIG. 2 engages between the spring mount  7  and the lever mount  17  (not shown in FIG.  1 ). 
     When the vacuum contactor is activated as shown in FIG. 1, the loose bearing  2  is moved in the interrupter  15  with the bellows element  3  and the compression spring  8  being compressed, as a result of which the guide elements  6 a,  6 b and  6 c are moved and guided in the respectively corresponding grooves  5   a  and  5   b  (longitudinal grooves) in the adjacent enclosure walls  31  and  32  (see FIG.  2  and FIG.  3 ). The guide element  6 d is located opposite the guide element  6 a (see FIG.  3 ), and cannot be seen in FIG.  1 . 
     As shown in FIG. 2, the stationary contact  1  is located on the stationary bearing  33  of the vacuum contactor and is conductively connected via the stationary bearing element  18  to the connecting rail  19  for the electrical current input. 
     FIG. 2 shows the vacuum contactor in the open switch position, with the bolt  16  of the loose bearing  2  being arranged in the interrupter  15  and in the bellows element  3  on the contact point  20 , at a distance from the stationary contact  1 . 
     The sleeve  22  and the angled element  28  are fitted to the bolt  16  via the attachment screw  21 . The lever  23  of the lever element  29  is located between the lever mount  17  and the spring mount  7 , and is held on the bearing element  24  such that it can rotate and, when the contact support  25  is operated in the movement direction  26 , results in the vacuum contactor being closed by movement of the bolt  16  of the loose bearing  2  toward the stationary contact  1 . 
     The angled element  28  is connected to the connecting rail  27  via the flexible strip  14 . When the vacuum contactor is closed, there is an electrical connection between the connecting rail  19  and the connecting rail  27  via the stationary contact  1  and the loose bearing  2 . 
     The loose bearing  2  is guided by the guide elements  6   a  to  6   d , which are essentially cuboid. In this case, the guide elements  6   a  and  6   d  are fitted on an annular element  9 , which surrounds the bolt  16  and has a projection  34 , which is used for positioning of the angled element  28  and of the compression spring  8 . The guide elements  6   b  and  6   c  are located on the spring mount  7 . 
     The interrupter assembly is held, as shown in FIG. 2, in an enclosure  4  with a removable cover  11 . The cover  11  has a cutout  30 , through which the indicator  10  of the annular element  9  can be seen. This allows the movement of the indicator  10  to be seen during movement of the loose bearing  2 , so that, when the enclosure  4  is closed with the cover  11  fitted, the position of the indicator  10  in the cutout  30  allows the operator to see the switching state of the vacuum contactor (open/closed). 
     The arrangement of the interrupter assembly in an inner chamber in the enclosure  4  between the enclosure walls  31  and  32  can be seen from FIG.  3 . The vacuum contactor is covered from above by the cover  11 . 
     The guide elements  6   a  and  6   d  of the annular element  9  are guided in the grooves  5   a  and  5   b , which are formed by interaction of the recesses  12   a  and  12   b  in the enclosure walls  31  and  32  with the contact surfaces  13   a  and  13   b  of the cover  11 , when the cover  11  is fitted. Thus, when the cover  11  is removed, the loose bearing  2  is conveniently accessible, for example for replacement. 
     The grooves  5   a  and  5   b  may also be formed by recesses which are located completely in the enclosure walls  31  and  32 , or by a recess on the cover  11 , which interacts with a contact surface in the enclosure  4  (not shown). 
     FIG. 3 also shows the contact support  25  with the lever element  29  held on it. The contact support  25  is moved in the movement direction  26  via a magnet system, which is not shown. at least the other of the housing of the vacuum contactor and a cover of the vacuum contactor. 
     The guide elements  6   b  and  6   c  are advantageously guided in the associated grooves  5  (or groove regions) with more play than the guide elements  6   a  and  6   d  in their associated grooves  5  (or groove regions), in order to allow the bolt  16  to tilt slightly during closing and opening of the loose bearing  2 , owing to the rotary movement of the lever  23  about the bearing element  24  (not shown). 
     The invention 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 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.