Patent Publication Number: US-10777369-B2

Title: Twin-roll blocking unit for a triggering mechanism for a switching device

Description:
PRIORITY STATEMENT 
     This application is the national phase under 35 U.S.C. § 371 of PCT International Application No. PCT/EP2016/071246 which has an International filing date of Sep. 9, 2016, which designated the United States of America and which claims priority to German patent application number 102015219041.2 filed Oct. 1, 2015, the entire contents of which are hereby incorporated herein by reference. 
     FIELD 
     An embodiment of invention generally relates to a triggering mechanism for a switching device, in particular for low-voltage devices and systems, medium-voltage devices and systems and/or high-voltage devices and systems. 
     BACKGROUND 
     The prior art discloses straightforward latching arrangements, for example vacuum contactors. In these, a drive lever is pushed into the “off” switching position via a compression spring. In order for the switching device to be readily retained in the “on” switching position, the drive lever is latched, that is to say blocked, mechanically. For this purpose, a latch block is fastened on the drive lever. In the “on” switch position, the drive lever is blocked by a bolt. The bolt is a constituent part of a lever which is retained in the latched position via a spring and the resulting spring force. It is possible for the blocking unit comprising the bolt and lever to be pulled out of the latched position via a solenoid (triggering magnet) and the magnetic field thereof and thus to free the drive lever, or else the lever and the bolt are pulled mechanically out of the latched position via a rod in order to free the drive lever. 
     Such a system allows for only very low tolerances, so as to avoid undesired unlatching, that is to say unblocking, of the drive lever. 
     Even low tolerances result, in such a system, in high levels of friction, in particular between the latch block and bolt. 
     Overall, the known systems require high triggering forces, for example approximately 100 N in the embodiment described, for mechanical triggering, that is to say unlatching. 
     It is also the case that high forces are necessary for electromagnetic triggering, or unlatching, for which reason expensive special-production measures are required for the triggering magnets, in other words electromagnets. The high triggering forces necessitate a solid component construction and strong springs. It is also necessary for the lever of the latching arrangement to be welded on account of the high forces, and this results in high-outlay production. 
     SUMMARY 
     The inventors have discovered that since the rod is subjected to transverse forces for mechanical triggering purposes, additional mounting is necessary in order for additional frictional forces to be prevented or minimized. 
     At least one embodiment of the invention provides a triggering mechanism which is more straightforward to produce and more cost-effective and, at the same time, prevents undesired unlatching, that is to say triggering, as a result of, for example, vibration. 
     At least one embodiment of the invention is directed to a triggering mechanism for a switching device, having a drive lever, a mechanical energy store, which is suitable for acting on the drive lever, and a blocking device. The blocking device preferably has a first blocking element on the drive lever, a lever with a first roller and a second roller, a second blocking element and a triggering element. The first roller and the second roller are mounted in a rotatable manner on the lever. 
     The second blocking element, in a locked position, acts on the first roller such that the lever is blocked against moving in the direction of the second blocking element, that is to say also in the direction of the third point of rotation, in other words the point of rotation of the second blocking element. 
     The second roller acts on the first blocking element such that the first blocking element is blocked against moving away from the mechanical energy store or in the direction of the mechanical energy store. 
     The expression “locked position” relates both to the lever being blocked against moving in the direction of the second blocking element and to the first blocking element being blocked against moving away from the mechanical energy store or in the direction of the mechanical energy store. 
     The second blocking element can be moved via the triggering element such that the second blocking element moves away, out of the locked position, from the first roller and the lever with the first roller and the second roller moves away out of the locked position, in which the first blocking element is blocked against moving away from the mechanical energy store or in the direction of the mechanical energy store, and therefore the first blocking element can roll over the second roller and the drive lever can be moved, by the energy stored in the mechanical energy store, away from the mechanical energy store or in the direction of the same. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter of the invention will be explained in more detail hereinbelow with reference to individual figures, in which: 
         FIG. 1  shows a sectional view of a latching arrangement from the prior art, 
         FIG. 2  shows a schematic drawing of the levers and forces for a latching arrangement according to  FIG. 1 , 
         FIG. 3  shows a section through a triggering device and latching arrangement according to an embodiment of the invention, 
         FIG. 4  shows a schematic illustration of the latching arrangement and triggering arrangement, and of the lever arms, according to  FIG. 3 , and 
         FIG. 5  shows a schematic illustration of the tilting of the second blocking element. 
     
    
    
     DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS 
     At least one embodiment of the invention is directed to a triggering mechanism for a switching device, having a drive lever, a mechanical energy store, which is suitable for acting on the drive lever, and a blocking device. The blocking device preferably has a first blocking element on the drive lever, a lever with a first roller and a second roller, a second blocking element and a triggering element. The first roller and the second roller are mounted in a rotatable manner on the lever. 
     The second blocking element, in a locked position, acts on the first roller such that the lever is blocked against moving in the direction of the second blocking element, that is to say also in the direction of the third point of rotation, in other words the point of rotation of the second blocking element. 
     The second roller acts on the first blocking element such that the first blocking element is blocked against moving away from the mechanical energy store or in the direction of the mechanical energy store. 
     The expression “locked position” relates both to the lever being blocked against moving in the direction of the second blocking element and to the first blocking element being blocked against moving away from the mechanical energy store or in the direction of the mechanical energy store. 
     The second blocking element can be moved via the triggering element such that the second blocking element moves away, out of the locked position, from the first roller and the lever with the first roller and the second roller moves away out of the locked position, in which the first blocking element is blocked against moving away from the mechanical energy store or in the direction of the mechanical energy store, and therefore the first blocking element can roll over the second roller and the drive lever can be moved, by the energy stored in the mechanical energy store, away from the mechanical energy store or in the direction of the same. 
     In at least one embodiment, such a triggering mechanism makes it possible for a switch to be reliably retained in an “on” position but to be transferrable, by the mechanical energy store loaded with energy, quickly and reliably into an “off” position, by virtue of the latching arrangement being unlatched by a triggering element, that is to say by a locking arrangement being released and unlocked. 
     An example embodiment of a triggering mechanism for a switching device is one in which the mechanical energy store is a spring element, further preferably a compression spring. 
     Another example embodiment of a triggering mechanism for a switching device is one in which the drive lever is mounted in a rotatable manner at a first point of rotation, and the lever is mounted in a rotatable manner at a second point of rotation and the second roller is arranged between the second point of rotation and the first roller. The second blocking element is mounted in a rotatable manner at a third point of rotation. 
     On that side of the third point of rotation which is directed away from the first roller and on the side which is directed toward the triggering element, the second blocking element butts against a stop which prevents that side of the second blocking element which is directed toward the first roller from rotating in the direction away from the second roller. The second blocking element can be made to rotate by the triggering element such that that side of the second blocking element which is directed toward the first roller, as seen from the third point of rotation, moves away from the first roller and in the direction of the second roller and—if necessary—also moves onward past the second roller, and therefore the lever moves in the direction of the third point of rotation, and the first blocking element rolls over the second roller and thus releases the first blocking element, it therefore being the case that the drive lever is caused to rotate, by the compression spring or the mechanical energy store, about the first point of rotation. 
     Another example embodiment of a triggering mechanism for a switching device is one in which the second blocking element is prestressed by a mechanical force by way of a rotary spring. 
     A further example embodiment is a triggering mechanism for a switching device in which the second blocking element is additionally secured against rotation by a mechanical force by way of a rotary spring and, in an unlocked position, subjects the blocking element to a restoring force in the direction of the locked position, wherein the unlocked position is distinguished in that the lever is not blocked against moving in the direction of the second blocking element, and in that the first blocking element is not blocked against moving away from the mechanical energy store or in the direction of the mechanical energy store. 
     A further example embodiment includes a triggering mechanism for a switching device in which the second roller is offset on the lever in the direction of the drive lever, as seen in relation to the first roller. 
     A further example embodiment includes a triggering mechanism for a switching device in which, in the locked position, the second blocking element, on the side directed away from the first roller, has been tilted in the direction of the stop by 0.2° to 0.5° in relation to a vertical axis, that is to say the long axis of the second blocking element when oriented vertically. In other words: in the locked position, in which the latch and/or the second blocking element butt/butts against the stop, the axis of the latch and/or of the second blocking element tilts by 0.2° to 0.5°, to be precise such that that side of the blocking element which, as seen from the third point of rotation, is directed away from the first roller has been rotated in the direction of the second roller. In particular, it is possible for the axis in relation to which the second blocking element has been tilted also to be formed by the axis through the third point of rotation and the point of rotation of the first roller. 
     A further example embodiment includes a triggering mechanism for a switching device is also one in which those edges of the second blocking element which are directed toward the first roller in the locked position are rounded. 
     In a further example embodiment, the first roller and second roller have different diameters. 
     A further example embodiment includes a triggering mechanism for a switching device in which the triggering element is a triggering magnet, in particular an electromagnet or a coil, in particular a solenoid. 
     A further example embodiment includes a triggering mechanism for a switching device in which the triggering magnet can be actuated both mechanically and electrically. 
     A further example embodiment includes a triggering mechanism for a switching device in which the necessary force for triggering the mechanical unlocking of the second blocking element via the triggering element is smaller than 50 N, preferably smaller than 30 N, preferably smaller than 25 N, and is further preferably 20 N (+/−) 2 N. 
     In a further example embodiment for a triggering mechanism for a switching device, the second blocking element is a latch or half-shaft. 
       FIG. 1  shows a latching arrangement and the associated triggering mechanism from the prior art, for example the Siemens 3TLG vacuum contactor. The drive lever  2 , with the point of rotation  1 , is pushed in the direction of the “off” switching position via a compression spring  5 . In order for the drive lever  2  and thus the switching device to be retained in the “on” switching position, the drive lever  2  is latched mechanically. 
     This latching takes place via a latch block  8 , which is fastened on the drive lever  2 . This latch block  8  is blocked in the “on” switching position by the bolt  12 . 
     The bolt  12  is a constituent part of the lever  3 , wherein the lever  3  is retained in the latched position by way of the force of the rotary spring  6 . 
     For unlatching purposes, that is to say in order to trigger the switch so that the latter can pass into the “off” switching position, either the solenoid  7  is energized, the magnetic field of the solenoid  7  pulling the lever  3  out of the latched position and thus freeing the drive lever  2 , or the lever  3  is pulled mechanically out of the locking position by the rod  10 , the bolt  12 , in turn, therefore freeing the latch block  8  and thus the lever  3 . 
     In order for undesirable forces to be reduced, the rod  10  is guided in a bearing  11 . 
     Also shown is a shim  9  beneath the solenoid. 
       FIG. 2  shows schematically, in the upper part, the basic construction of the triggering device according to the prior art. 
     The drive lever  20  is mounted in a rotatable manner at the point of rotation of the drive lever  1 . The compression spring  50  acts on the drive lever  20 . The drive lever  20  is retained in the “on” position by the bolt  120  as long as the switch is located in the “on”/latched switch position. 
     The bolt  120  is fastened on the lever  30  and the lever  30  is mounted in a rotatable manner at the point of rotation  40 , and the rotary spring  60  retains the lever in the latched position, or pushes it into said position. 
     The lever  30  can be moved out of the locked position either via the rod  100  or via the solenoid  70 , and therefore the drive lever  20  is freed and can be moved by the compression spring  50 . 
     The lower part of  FIG. 2  likewise shows the drive lever  20  in the locked position, wherein the lever arm of the bolt  130 , the lever arm of the coil  140 , the lever arm of the rod  150  and the transverse force  160  are shown. 
       FIG. 3  shows a section through a triggering mechanism according to the invention. The drive lever  112  is mounted in a rotatable manner at a point of rotation of the drive lever  111 . In the “on” switching position, the drive lever  112  is blocked by the second roller  1110 , via the first blocking element  1116 , which may be designed in the form of a latch, from moving away from the mechanical energy store, in this case a compression spring  115 . The blocking element  1116  is fixed to the drive lever  112 . The second roller  1110  is mounted in a rotatable manner on the lever  113 . The lever  113  itself is mounted in a rotatable manner at the point of rotation of the lever  113 , in other words the second point of rotation  114 . 
     In the locked position, that is to say in the “on”/latched switching position of the switch, the lever  113  is prevented by a second blocking element  118 , via the first roller  1111  mounted in a rotatable manner on the lever  113 , from moving away from the first blocking element  1116 . The second blocking element  118  is located beneath the third point of rotation  119 , on which the second blocking element  118  is mounted in a rotatable manner, and, on that side which is directed toward the point of rotation of the lever  113 , that is to say the second point of rotation  114 , butts against a stop  1119 . It is also possible for the stop  1119 , in principle (not shown here), to be provided above the third point of rotation  119 , on which the second blocking element  118  is mounted in a rotatable manner, and on that side of the second blocking element  118  which is directed away from the point of rotation of the lever  113 , that is to say the second point of rotation  114 . 
     For triggering or unlatching purposes, it is possible for the triggering element  117  to cause the second blocking element  118  to move, or rotate, either mechanically or electronically. As a result of this movement, the second blocking element  118  moves away from the first roller  1111  and thus frees the lever  113 . In particular, it is possible for that end of the second blocking element  118  which is directed toward the first roller  1111  to move away from the first roller  1111  and in the direction of the second roller  1110 , and—if necessary—also to move onward past the second roller  1110 . The freed lever  113  is moved in the direction of the second blocking element  118  and thus allows the first blocking element  1116  to roll over the second roller  1110  of the lever  113 . The thus freed, unlatched or unlocked drive lever  112  can then be rotated by the mechanical energy store  115 , in this case a compression spring  115 , about the point of rotation  111  of the drive lever and thus move the switch into an “off” position. 
     In the case of the switch being transferred into the “on” position, a rotary spring  116  at the point of rotation of the second blocking element  118 , that is to say the third point of rotation  119 , causes the second blocking element  118  to be rotated back again into the latched or blocked position, which enables, or moves, the lever  113  to block the first blocking element  1116 . 
     The upper part of  FIG. 4  shows the construction of  FIG. 3  in a schematic representation. The drive lever  112  is mounted in a rotatable manner at the point of rotation  111  of the drive lever. The drive lever  112  is blocked by the second roller  1110  and the spring  115  is prevented from pushing the drive lever  112  out of the blocked position. The second roller  1110  is connected to the point of rotation of the lever  113 , that is to say the second point of rotation  114 , via the lever arm  113 ′. The first roller  1111  is also fastened on the lever  113 , and the lever  113  is prevented by the second blocking element  118 , which acts on the first roller  1111 , from moving in the direction of the second blocking element  118 . The second blocking element  118  is mounted in a rotatable manner, by way of the rotary spring  116 , at the point of rotation of the second blocking element  118 , that is to say the third point of rotation  119 . The triggering element  117  is provided such that it can act on the second blocking element  118  and, via a rotary movement of the second blocking element  118  being initiated, can free the lever  113  and thus the drive lever  112 . 
     The lower part of  FIG. 4  illustrates the lever arms in respect of the lever  113  and of the second blocking element  118 . The lever arm  1113  of the first roller  1111  and the lever arm  1112  of the second roller  1110  are likewise indicated, as are the lever arm  1114  of the second blocking element  118  and the lever arm  1115  of the triggering element  117 . 
       FIG. 5  shows a schematic diagram of the latched state of the second blocking element  118 , which, for self-locking purposes, has been tilted or “over-extended” by 0.2° to 0.5°. The figure shows the axis  1121  of the lever  113  and the point of rotation of the lever  113 , that is to say the second point of rotation  114 , and the first roller  1111 , which is retained in the locked or latched position by the second blocking element  118 . The second blocking element  118  has been tilted at the third point of rotation  119  of the second blocking element  118  so as to result in self-locking. This self-locking is achieved in that the point of rotation of the first roller  1111  is located along an axis with the third point of rotation  119  of the second blocking element  118 , and the stop  1119  of the second blocking element  118  is provided such that, in the latched or locked position, the axis of the latch has been rotated 0.2° to 0.5° in relation to the common axis of the first roller  1111  and of the third point of rotation  119  of the second blocking element  118 . The rotation takes place, from the third point of rotation  119 , on that side of the second blocking element  118  which is directed toward the first roller  1111  and in the direction which is directed away from the point of rotation  114  of the lever  113 . Also shown is the force vector  1130 , which results from the rotation and is responsible for the self-locking, that is to say the “over-extension”. 
     LIST OF REFERENCE SIGNS 
     
         
           1  Point of rotation of the drive lever  2   
           2 ,  20  Drive lever 
           3  Lever 
           4 ,  30  Point of rotation of the lever 
           5 ,  50  Mechanical energy store, spring, compression spring 
           6 ,  60  Rotary spring 
           7 ,  70  Solenoid 
           8  Latch block 
           9  Shim 
           10 ,  100  Rod 
           11  Bearing 
           12 ,  120  Bolt 
           130  Lever arm of the bolt 
           140  Lever arm of solenoid 
           150  Lever arm of rod 
           160  Transverse force 
           111  Point of rotation of the drive lever  112 , first point of rotation 
           112  Drive lever 
           113  Lever 
           114  Point of rotation of the lever  113 , second point of rotation 
           115  Mechanical energy store, spring, compression spring 
           116  Rotary spring at the point of rotation of the lever  113   
           117  Triggering element, triggering magnet, electromagnet 
           118  Second blocking element, latch 
           119  Point of rotation of the second blocking element, third point of rotation 
           1110  Second roller 
           1111  First roller 
           1112  Lever arm of the first roller 
           1113  Lever arm of the second roller 
           1114  Lever arm of the second blocking element, of the latch 
           1115  Lever arm of the triggering element 
           1116  First blocking element 
           1119  Stop of the second blocking element, of the latch 
           1120  Axis of the second blocking element, of the latch 
           1130  Resultant force vector 
         A Tilting by 0.2° to 0.5°, over-extension for self-locking 
         B Direction for the mechanical triggering, unlatching