Abstract:
The invention is a device for displacing a switch blade between a position on a stock rail and a position at a distance from the stock rail. The device has: a locking bearing coupled to the switch blade and connected to a locking catch via an axle; and a locking rod that guides the locking catch against a locking support coupled to the stock rail, locks the locking catch to the support, and then unlocks and guides it away from the locking support. The locking support is positioned on the side of the stock rail opposed to the switch blade and is connected to a thrust bearing that is arranged on a fixed superstructure component. The locking bearing is arranged on a component that at least partially follows the displacement, and the displacement motion is transferred from the locking bearing to the switch blade via a displaceable push rod.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a device for displacing a switch blade between a position on a stock rail and a position at a distance from the stock rail. 
     Railroad switches are fitted with locking devices for the purpose of securing switch blades, as disclosed for instance in European patent application EP 0 885 795 A1. This European patent application discloses the function of a modern locking device (latching closure CKA). Said document discloses not only the locking and unlocking but also the displacement of the switch blades, which in the case of a latching closure take place with the aid of a locking rod and a locking catch. The switch blade connected to the locking catch via a locking bearing is brought into contact with the associated stock rail during the locking procedure of the locking rod, during which the locking catch is guided under the stock rail and pressed upward against the foot of the stock rail, that is, against the locking support arranged at the foot of the stock rail, by the locking rod for locking the switch blade. 
     Particularly in the case of switch blades which are quite long, as they need to be for the larger radiuses, undesirable oscillations occur during use. These switch blades are furthermore at increased risk of torsion, as a result of which the switch blade can lift clear of the stock rail. It is known that document EP 0 624 508 A1 discloses a locking device which seeks to achieve a tight connection between the switch blade and the stock rail. This is achieved by providing the locking bearing connected to the switch blade with an elongation which presses against a locking support firmly connected to the stock rail when the locking device locks, as a result of which the switch blade pivots about the locking bearing and is pressed tightly against the stock rail. 
     Moreover German patent application DE 43 15 200 A1 discloses a locking device according to the document EP 0 624 508 A1 mentioned above. Said device is integrated into a hollow-section cross-tie, enabling automatic tamping of the track ballast in the region of the switch displacement device, that is, especially in the region of the tips of the switch blades. 
     It is common to all the above-mentioned reference documents that the locking support at the foot of the stock rail is held by gripping the foot of the stock rail on both sides and/or the locking catch is held in the locking bearing which is directly fastened to the switch blade. It is therefore easy to understand that, particularly in countries such as the USA, the UK and Japan, which have a great plurality of track and switch blade profiles, a correspondingly large number of different locking supports and/or locking bearings needs to be held in inventory and used in line with demand. It is thus expensive and time-consuming to store and use such items in this way in view of the plurality of profiles which exist. Even with only slight differences between one profile and another there is a risk that the construction team, which as a rule installs switches when the line is open to traffic, and is therefore always working under a certain amount of time pressure, might get the profiles mixed up. Such mistakes however can lead to premature wear or even to a serious malfunction. 
     SUMMARY OF THE INVENTION 
     The object of the invention is thus to specify a displacement and locking device for switch blades which manages with a particularly small number of parts despite the presence of a diversity of rail and switch profiles, at the same time making the work of the construction team efficient and to a large extent eliminating sources of error. 
     This object is achieved in a first variant of the previously mentioned displacement and locking device to which the invention relates, in that the device has the following components:
         a) a locking bearing which is coupled to the switch blade and connected to a locking catch by means of an axle, and   b) a locking rod that guides the locking catch against a locking support coupled to the stock rail, locks the locking catch to the support and then unlocks the same and guides it away from said locking support,   c) the locking support being positioned on the side of the stock rail opposed to the switch blade, and being connected to a thrust bearing that is arranged on a fixed superstructure component.       

     By this means the locking support is successfully fastened to the stock rail without the need to fix fastening elements to the stock rail on the side of the stock rail facing toward the switch blade. This results in a “clear” inner profile against which the widest range of switch blade profiles can press. The fixed superstructure component, being a component which already exists in the track area and/or in the area of a switch, can therefore be utilized for -fastening the locking support and meets the requirement to leave the above-mentioned inner profile clear. 
     A particularly appropriate solution proposes using a component for supporting the switch blade as the fixed superstructure component. Such a component is designed to be very stable and is therefore suitable for holding the fastening of the locking support onto the inner side of the stock rail, if necessary even by tensioning the locking support. A switch blade slide chair proves to be particularly suitable for this purpose. This slide chair can also take the form of a switch blade slide bearing or a switch blade roller bearing. 
     As already disclosed in German patent application 43 15 200, a switch displacement device can also be integrated into a hollow-section cross-tie. In such a case it is particularly advantageous in an embodiment of the invention if the fixed superstructure component is arranged on a rising edge of a cross-tie member having a U-shaped profile. 
     In principle however, virtually any flange attached to a cross-tie member is suitable as a fixed superstructure component. This flange merely needs to be stable enough to act as a thrust bearing for the locking support fastening. The flange can obviously therefore be strengthened with the aid of supporting bridge pieces or the like. 
     A particularly appropriate fastening for the locking support occurs on the outer side of the stock rail (the side of the stock rail facing away from the switch blades) if the locking support is tightly coupled in the foot area of the stock rail. The locking support can then enclose the foot of the rail like a clamp on the outer side and thus be tensioned in a direction which is mainly vertical to the longitudinal extent of the stock rail. 
     The object mentioned above is further achieved in a second variant of the previously mentioned displacement and locking device to which the invention relates, in that the device has the following components:
         a) a locking bearing which is coupled to the switch blade and connected to a locking catch by means of an axle, and   b) a locking rod that guides the locking catch against a locking support coupled to the stock rail, locks the locking catch to the support and then unlocks the same and guides it away from said locking support,   c) the locking bearing being arranged on a component that at least partially follows the displacement and the displacement motion being transferred from the locking bearing to the switch blade by means of a displaceable push rod.       

     This method avoids any direct connection between the locking bearing and the switch blade without having to give up the advantages of the locking bearing whereby the locking catch is supported so that it can rotate about an axle that is mainly parallel to the longitudinal extent of the stock rail. The push rod deals with the adaptation to different switch blade profiles, and is accordingly designed to be displaceable. A locking component that follows the displacement of the locking rod is for example the locking rod itself, the push rod or a component which is itself an element in the system linking the push rod to the locking rod. Such a component can also be an additional supporting element or slide member or the like which is fastened to one or more of the above-mentioned components and therefore supports the locking bearing. 
     A preferred variant in an embodiment of the invention proposes connecting the push rod firmly to the switch blade and holding it in the locking bearing so that it is movable. As a rule this variant requires a drill hole in the switch blade so that the push rod can be bolted to the switch blade. However, a solution in which the push rod has no drill hole but is held on the switch blade by clamping or tensioning or the like is also conceivable. 
     As an alternative the push rod can be held in the locking bearing so that it is movable and the two switch blades can be connected by means of a coupling rod. Then in the event of displacement, one switch blade is pushed as far as the stock rail by the push rod and the other switch blades are pulled away by the stock rail with the aid of the coupling rod in each case. In this case also, virtually any number of different switch blade profiles can be accommodated thanks to the mobility of the push rod in the locking bearing. 
     In a further embodiment of the invention the push rod can be held in the locking bearing and prevented from moving by means of a defined tractive power. Thus the switch blades can be forced open in a way that is non-destructive for the switch displacement mechanism, the alternative solution having been for example to install components in which the desired breaking points are predefined. According to this variant, instead of broken components having to be replaced when the switch blades have been forced open, the push rod need only be moved back to its original position and once more fastened with the predefined tractive power. In this case said tractive power can be provided by a spring-loaded catch. Embodiments are therefore conceivable in which a sphere or a cylinder is pressed into a bulge in the push rod by means of a spring. Thanks to this bulge it is also possible to return the push rod to the correct position (after the switch blades have been forced open) without any special adjustment tools or the like, because the best and thus the correct final position of the push rod can be found almost automatically due to the force of the spring. 
     Lastly the object mentioned above is achieved in yet a third variant according to the invention. This third variant is a combination of the first and second variants, and has the following features: Device for displacing a switch blade between a position on a stock rail and a position at a distance from the stock rail, having:
         a) a locking bearing which is coupled to the switch blade and connected to a locking catch by means of an axle, and   b) a locking rod that guides the locking catch against a locking support coupled to the stock rail, locks the locking catch to the support and then unlocks the same and guides it away from said locking support,   c) the locking support being positioned on the side of the stock rail opposed to the switch blade, and being connected to a thrust bearing that is arranged on a fixed superstructure component; and   d) the locking bearing being arranged on a component that at least partially follows the displacement and the displacement motion being transferred from the locking bearing to the switch blade by means of a displaceable push rod.       

     Further advantageous embodiments of the invention are to be found in the remaining sub-claims. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       Exemplary embodiments of the invention will be explained in greater detail with the aid of the attached drawings. These show the following: 
         FIG. 1  a side view of a first displacement device for a switch blade; 
         FIG. 2  a side view of a second displacement device for a switch blade; and 
         FIG. 3  a locking device known from document EP  0   624   508  Al. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 3  shows a locking device  2  which is known from document EP 0 624 508 A1 and which has a locking catch  10  connected by means of an axle  4  and a locking bearing  6  to a switch blade  8 ; after closing, said locking catch presses tightly against a surface  12  of a locking support  16  connected to a stock rail  14  and is firmly blocked in that position by a locking rod  18 . The locking bearing  6  is provided underneath with an extension (not shown in greater detail) which when the locking device is closed abuts against the locking support  16 , transmitting a force F 1  to the locking bearing  6  and causing a head  20  of the switch blade  8  to be pressed against the head  22  of the stock rail  14 . The locking bearing  6  is connected by a bolted connection  24  to the foot  26  of the switch blade  8 , said switch blade being designed in such a way that its foot  26  rests on the foot  28  of the stock rail  14  when the head  20  of the switch blade  8  is pressed against the head  22  of the stock rail  14 . It is therefore easy to see that the locking bearing  6  can readily be fastened to the foot  26  of the switch blade  8 . Similarly the locking support  16  can also be tensioned against the foot  28  of the stock rail  14  by means of a clamping screw  30  and a clamping hook  32 . 
     However, this embodiment of the locking device  2  cannot be used if for example the switch blade  8  has a different profile so that there is no room available at the foot  28  of the stock rail  14  for the fastening of the clamping hook  32 . This embodiment is also problematical if there is a great plurality of different profiles for the stock rails and switch blades in a rail network. In this case a separate locking bearing and a separate locking support must be used for each profile. 
       FIG. 1  is a diagram showing a side view of a first locking device  100  according to the invention, in which support is provided for a locking support  102  and a locking bearing  104  in a way that is independent of the respective profiles of the stock rail  14  and of a switch blade  106  that has been changed in comparison with  FIG. 3 . 
     As in  FIG. 3 , the locking support  102  is fastened on the side  108  facing away from the switch blade  106 , by virtue of its tight grip on the foot  28  of the stock rail  14 . At the same time, however, a thrust bearing is created in the form of a bolt  110 , so that the locking support  102  can be tensioned by means of a clamping screw  112  and a hooked rod  114 . The bolt  110  is attached in a manner not shown here to a superstructure component, for instance on the inner side of a hollow-section cross-tie or on the underside of a slide bearing for the switch blade  106 . For the sake of a clearer main illustration, this figure shows the bolt  110  to be arranged below the foot  26  of the switch blade  106 . It is clear that when the arrangement is this low, the tensioning could give rise to outwardly directed torque which could have a generally undesirable effect on the stock rail  14 . The bolt  110 , or in general terms, a thrust bearing for fastening the locking support  102 , is therefore as a rule arranged at a level which will avoid giving rise to outwardly directed torque (except of course in cases where such outwardly directed torque may be expressly desired). 
     Due to this method of support using the concept of a thrust bearing arranged on a superstructure component which as a rule already exists, enough clear space remains in the interior space  116  facing toward the switch blade  106  for switch blades  106  that are milled from the profile of the stock rail  14  also to be brought into play on the stock rail  14 . 
     The locking bearing  104  has likewise been mounted in a way which enables completely different switch blade profiles to be used. The locking bearing  104  is hence supported with the aid of a slide plate  118  which closely engages with a superstructure component by means of a sliding fit. In the present example the superstructure component is a cover plate  119  (partially shown) which closes the space in a hollow cross-tie or a cross-tie compartment in an upward direction. Arranged on this cover plate  119  are L-shaped guides  121  having a part  123  running horizontally on which the slide plate  118  slides. By this means the displacement is transmitted from the locking rod  18  via the locking catch  10  to the locking bearing  104  fastened to the slide plate  118 . When the switch blade  106  is displaced, the slide plate  118  is moved forward and back between the two end-positions of its travel. As an alternative to a sliding support for the slide plate  118  a roller bearing or the like can also be used. The slide plate  118  is thus supported on the guides  121 ,  123 , which also act as slide bearings. The guides  121 ,  123  therefore bear the weight of the locking bearing  104 . The locking catch  10  is supported, as mentioned, on the axle  4  in the locking bearing  104 . In the upper part of the locking bearing  104  a push rod  120  is supported in a drill hole in such a way that it can move. The push rod  120  is locked in each final position, enabling the front end  122  of the push rod  120  to press accurately against the switch blade  106 . When the switch is displaced the push rod  120  abuts against the switch blade  106  in the position shown in  FIG. 1 . By means of a coupling rod (not shown) for the two switch blades  106 , the push rod  120  affects the other side of the locking device  100  opposite the split pin  124  in the axially symmetrical drive rod  126 , so that the opposite switch blade abuts against the opposite stock rail and the switch blade  106  shown in  FIG. 1  is then guided away from the stock rail  14 . The previously mentioned coupling rod between the two switch blades  106 , also known as a tie rod, can also be achieved by means of a continuous slide plate  118  which either itself has elements coupled to the switch blades  106  or is part of an arrangement in which the push rods  120  are able not only to push a switch blade into a desired position but also to pull a switch blade into a desired position. It can then be an advantage, particularly in the last mentioned case, to design the slide plate  118  separately for each locking bearing  104 . This results in the ability to force open the switch without the slide plate  118  being damaged, as would be the case with a continuous slide plate  118 , because when the switch is forced the second of the two switch blades  106  is forced into a position away from the stock rail  14  in each case. 
       FIG. 2  is a diagram showing a side view of a second locking device  130 . For the most part only the mountings for a locking support  132  and for a locking bearing  134  are shown for the sake of clarity. The whole locking device  130  is integrated in a hollow-section cross-tie  136 , open in the upward direction, having a U-shaped profile and outward facing flanges  138 . Mounted on these flanges  138  and secured by means of bolted connections  139  is a slide chair  140  for a switch blade  142 . A stock rail  144 , modified in profile compared to the previously described stock rails  14 , is also fastened on the flanges  138  by means of bolted connections  146 . 
     A bolt  148  which projects sideways is provided on the inward facing sides of the slide chairs  140  in each case, and acts as a thrust bearing for the fastening of the locking support  132 . Due to the way it is mounted, the locking support encloses the foot  150  of the stock rail  144  on its outer side  152  and is fastened by means of a clamping screw  154 , which tensions a hooked rod  156  gripping the bolt  148 . This fastening is provided on both the slide chairs  140  fastened on the flanges  138 . In view of the profiles of stock rail  144  and switch blades  142  present at this point it is easy to understand that at the foot  150  of the stock rail  144  no room would be available on its inner side for the fastening of the locking support  132 . The fastening of the locking support  132  can however be achieved in a way previously described without a drill hole in the stock rail, as is often required by rail infrastructure operators. 
     The locking bearing  134  is also fastened in a correspondingly flexible manner. The locking bearing  134  is fastened to a slide member  135  which itself rolls (idlers  137  indicated by broken lines) in a guideway  141  arranged on the inward facing lateral surfaces of the slide chairs  140 . In the locking bearing  134 , the locking catch (not shown) is supported as before so that it can rotate about the axle  4  and is held in an eccentric bush  5  (cf.  FIG. 1 ). Moreover the locking bearing  134  has a mainly horizontal drill hole in which a push rod  156  is held in such a way that it can move. The push rod  156  can be connected firmly to the switch blade  142  by means of a threaded connector arranged on said push rod  156 . 
     Additionally the push rod  156  has a cylindrical recess  158  into which a roll body  162  is pressed by a spring  160 . The spring  160  is tensioned by means of a bolt  164  which is screwed into a vertical spring casing  166 . A predefined tractive power can be exerted on the push rod  156  by selecting a particular thickness for a washer  168 . The tractive power is chosen so as to enable the switch to be forced open in the direction of travel when traffic passes over it. When a wheel rim penetrates the locked switch blade  142  a force is exerted on the switch blade  142  in the direction of an arrow  170 . When the tractive power exerted by the spring  160  is overcome, the push rod  156  is moved in the direction  170 . It is true that an adjustment to the push rod  156  has become necessary as a result, but total destruction of the displacement device due to the forcing can be reliably avoided in this way. 
     The second locking device  130  therefore also shows the desired advantages of easy adaptability to different profiles of the stock rail  144  and of the switch blades  142 , as was also demonstrated with the first locking device  100 . 
     KEY TO REFERENCE CHARACTERS 
     
         
           2  Known locking device 
           4  Axle 
           5  Eccentric bush 
           6  Locking bearing 
           8  Switch blade 
           10  Locking catch 
           12  Surface 
           14  Stock rail 
           16  Locking support 
           18  Locking rod 
           20  Head of the switch blade  8   
           22  Head of the stock rail  14   
           24  Bolted connection 
           26  Foot of the switch blade  8   
           28  Foot of the stock rail  14   
           30  Clamping screw 
           32  Clamping hook 
         F 1  Force 
           100  First locking device according to the invention 
           102  Locking support 
           104  Locking bearing 
           106  Switch blade 
           108  Side facing away from the switch blade  106   
           110  Bolt 
           112  Clamping screw 
           114  Hooked rod 
           116  Interior space 
           118  Slide plate 
           119  Cover plate 
           120  Push rod 
           121  L-shaped guide 
           122  Front end of the push rod  120   
           123  Horizontal part of the L-shaped guide  121   
           124  Split pin 
           126  Drive rod 
           130  Second displacement device according to the invention 
           132  Locking support 
           134  Locking bearing 
           135  Slide member 
           136  Hollow-section cross-tie 
           137  Idlers 
           138  Flanges 
           139  Bolted connection 
           140  Slide chair 
           141  Guideway 
           142  Switch blade 
           144  Stock rail 
           146  Bolted connection 
           147  Hooked rod 
           148  Bolt 
           150  Foot of the stock rail  144   
           152  Side facing away from the switch blade  142   
           154  Clamping screw 
           156  Push rod 
           158  Cylindrical recess 
           160  Spring 
           162  Roll body 
           164  Bolt 
           166  Spring casing 
           168  Washer 
           170  Arrow