Abstract:
A switch machine for a railroad switch provided with two switch points interconnected by transverse bars, including a fixed housing mounted between the switch points; two operating rods extending from the housing to the switch points; a shifting body within the housing, capable of sliding relative to the housing to simultaneously displace the operating rods; a control rod to displace the shifting body between two end stroke points; and engagement means within the housing for selectively engaging the operating rods to the housing at the two end stroke points.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    Not Applicable 
     
    
     
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT  
         [0002]    Not Applicable  
         BACKGROUND OF THE INVENTION  
         [0003]    1. Field of the Invention  
           [0004]    The present invention is in the field of railroad switching devices, namely the equipment which is used to displace railroad switch points. More specifically, the invention refers to a switching device for use with interconnected railroad switch points.  
           [0005]    2. Background Art  
           [0006]    A railroad switch point consists of tapered rail sections which are capable of being selectively displaced between two different positions at a rail switch and then locked in the selected position, in order to facilitate the desired routing of a train passing through the switch. The two switch points are typically displaced by rods extending from an assembly which is referred to herein as a “switch machine”. Inside the switch machine the rods are usually connected to a motive mechanism which provides reciprocating rectilinear motion, controlled by a power unit which is usually placed to one side of the rails.  
           [0007]    Such a device is described in Italian Patent No. IT1246656, to the inventor herein. The device described in that patent operates switch points which are independent, or disconnected, from each other, and it is not applicable to the problem of operating switch points of the interconnected type, i.e. of switch points connected to each other by transverse bars. Switch machines of the interconnected type are shown, for example, in U.S. Pat. Nos. 5,806,809 and 6,149,106.  
           [0008]    Among the features of the present invention is the provision of an improved switch machine for the selective displacement of interconnected switch points. A second feature of the present invention is a highly reliable switch machine mechanism. Further features of the device disclosed herein include combining the switch point movement and switch point locking functions into a single mechanism to reduce mechanical complexity, enclosing the mechanism in a weather-proof housing, incorporating sensors and other electrical control components in the housing and locating the housing and operating assembly beneath the switch points and the associated rails.  
         BRIEF SUMMARY OF THE INVENTION  
         [0009]    More particularly, the present invention provides a switch machine for operating a switch having switch points interconnected by one or more transverse bars. The switch includes a fixed housing with an upper plate and a lower guide fixed therein. Two operating rods extend from either side of the fixed housing to the movable switch points, with the rods being capable of longitudinally sliding with respect to the fixed upper plate. A skate inside the housing is capable of sliding with respect to the fixed lower guide. An intermediate shift assembly is mounted to the skate for movement with respect to the fixed lower guide. A control rod is provided to selectively attach to the intermediate shift assembly to displace or stroke the intermediate shift assembly in opposite directions between two end points of the stroke. The machine also includes a first engagement mechanism for selectively engaging the operating rods to the fixed upper plate or to the skate to selectively move the switch points, and a second engagement mechanism for selectively engaging the intermediate shift assembly to the control rod and/or to the fixed lower guide to selectively lock the operating rods and the switch points in a desired position.  
           [0010]    The novel features of this invention, as well as the invention itself, will be best understood from the attached drawings, taken along with the following description, in which similar reference characters refer to similar parts, and in which: 
       
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS  
       [0011]    [0011]FIG. 1 is an exploded view of the lower components of a switch machine according to the present invention;  
         [0012]    [0012]FIG. 2 shows the switch mechanism holding the switch points in the full right position in the locked mode;  
         [0013]    [0013]FIG. 3 shows the switch machine in the full right position of FIG. 2, but with the control rod moved to the left to unlock the switch machine to move the switch points;  
         [0014]    [0014]FIG. 4 shows the switch machine with the control rod moved further to the left to move the switch points from the full right position toward the full left position;  
         [0015]    [0015]FIG. 5 shows the switch points moved to the full left position;  
         [0016]    [0016]FIG. 6 shows the switch machine locked and latched in its full left position;  
         [0017]    [0017]FIG. 7 shows the functioning of the switch machine in the event of blockage preventing movement to its full left position; and  
         [0018]    [0018]FIG. 8 shows the functioning of the switch machine in the event of the displacement of the left rail preventing engagement by the left switch point in its full left locked position. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0019]    As seen in the attached drawings, the switch machine of the present invention includes three basic types of fixed components: a fixed housing  1 ; a plate  2  fixedly mounted within or otherwise attached to the housing  1 ; and two guides  3  fixedly mounted within or otherwise attached to the housing  1 , below the level of the fixed upper plate  2 . A capture mechanism, including a plurality of capture elements and a shifting body, is used to selectively engage and disengage two operating rods  4 ,  5  to and from the fixed upper plate  2 . More specifically, an upper set of interlocking or capture elements are provided to selectively interlock or engage the two operating rods  4 ,  5  with either the fixed upper plate  2  or the shifting body within the housing  1 . As part of the upper set of interlocking elements, the fixed upper plate  2  is provided with two ball seats  24  mounted on the upper side thereof. Each of the ball seats  24  houses a corresponding disk or follower plate  21  which can be completely inserted in its respective ball seat  24  against the action of a spring  22 . A lower set of interlocking elements are also provided to selectively interlock the shifting body with either the two fixed lower guides  3  or a control rod  8 . As part of the lower set of interlocking elements, each of the two fixed lower guides  3  is provided with two transverse pin seats  32 , with each pin seat  32  having sloping walls.  
         [0020]    The movable components of the present invention include the two operating rods  4 ,  5  which slidingly contact the lower side of the fixed plate  2 , and which move the two switch points A 1 , A 2  transversely. The switch points A 1 , A 2  are connected by one or more transverse bars  9 , so that the switch points A 1 , A 2  always move together and maintain their transverse spacing. The switch points A 1 , A 2  can move so that they contact either of two stock rails C 1 , C 2  for the purpose of directing a passing rail car along the desired track. Each operating rod  4 ,  5  is provided with a through hole  41 ,  51  sized to allow a ball  42  to pass therethrough, with each ball  42  being sized to pass into one of the ball seats  24 . The thickness of each operating rod  4 ,  5  in the vicinity of its respective through hole  41 ,  51  is at least half the diameter of the ball  42 . One skilled in the art will recognize that a pin of suitable configuration could be used instead of the ball  42 , and it could pass through corresponding shaped slots instead of the through holes  41 ,  51 , without departing from the concept of the present invention.  
         [0021]    The shifting body within the housing  1  includes a skate  6  and an intermediate shift assembly  7 . The skate  6 , which slidingly contacts the lower sides of the operating rods  4 ,  5  is provided with two ball slots  61 ,  62  recessed into its upper surface, oriented transverse to the longitudinal axis of the skate  6 . The wall of each ball slot  61 ,  62  closest to the center of the skate  6  slopes upwardly toward the center. Each ball slot  61 ,  62  is able to accept one of the balls  42 , with the depth of the ball slot  61 ,  62  being no more than half the diameter of the ball  42 . On the lower side of the skate  6  a semi-cylindrical lower central cavity  63  is provided, with the axis of the semi-cylindrical cavity  63  being parallel to the longitudinal axis of the skate  6 . Two transversely oriented stabilizing recesses  65  are provided in the lower side of the skate  6 , one stabilizing recess  65  being positioned beyond each end of the central cavity  63 . Each stabilizing recess  65  is capable of housing one transversely oriented, cylindrical, end stroke stabilizing pin  66 .  
         [0022]    The intermediate shift assembly  7  is positioned in contact with the lower side of the skate  6 , with the longitudinal axis of the shift assembly  7  parallel to the longitudinal axis of the skate  6 . The shift assembly  7  includes a hollow central cylinder  71 , provided with a cylindrical sleeve  72  fixedly surrounding each end of the central cylinder  71 . Each sleeve  72  has two symmetrical wings  73  extending radially therefrom, transverse to the longitudinal axis of the shift assembly  7 . The upper portion of the central cylinder  71  and the cylindrical sleeves  72  of the shift assembly  7  can be securely inserted into the central cavity  63  on the lower side of the skate  6 . The symmetrical wings  73  rest flat on the upper sides of the fixed guides  3 , with the lower portions of the central cylinder  71  and the cylindrical sleeves  72  positioned between the fixed guides  3 . Through slots  74  are provided in each of the wings  73 , through which transversely oriented, cylindrical, shift pins  75  can pass in order to seat in the pin seats  32  in the upper sides of the fixed guides  3 .  
         [0023]    The control rod  8 , controlled by an external power unit not shown in the drawings, enters the housing  1  from one side. The control rod  8  can slide through the whole shift assembly  7 , and it is provided with U-shaped right and left shift forks  81 ,  83  straddling the outer ends of the sleeves  72 . The shift forks  81 ,  83  are fixedly mounted on, or integral with, the control rod  8 , and they can partially slide over the tops of the wings  73  of the shift assembly  7 . On the upper surface of each of the forks  81 ,  83  an approximately semi-cylindrical transverse groove  82  is provided, to receive the stabilizing pins  66  which are housed in the stabilizing recesses  65  in the lower side of the skate  6 .  
         [0024]    An external power unit (not shown) can be provided outside the rails, and mounted to one side of the housing  1 , with a drive shaft, as is known in the art, passing under the rails and connected to the control rod  8  for achieving bidirectional longitudinal movement of the control rod  8 .  
         [0025]    In FIGS.  2  to  6 , the sequential steps of the normal functioning of the switch machine are illustrated, and the relative positions of the switch machine components are shown. In FIG. 2, the right switch point A 2  is in contact with the right stock rail C 2  at the full right end position of the stroke, and the control rod  8  is stabilized relative to the skate  6  by the left end stroke stabilizing pin  66  which is seated in the groove  82  on top of the left fork  83  and partially housed in the left stabilizing recess  65  in the lower side of the skate  6 . In this position, the right operating rod  5  is captured relative to the fixed plate  2  by the right ball  42 , which is partially housed by the right through hole  51  in the rod  5  and partially housed in the right ball seat  24  of the plate  2 . Of course, because of the rigid connection between the switch points A 1 , A 2  effected by the transverse bar  9 , the left operating rod  4  is also held in place relative to the fixed plate  2 . Therefore, in the configuration shown in FIG. 2, the switch points A 1 , A 2  are held in place at the right end of the stroke. Further, in this configuration, the shift assembly  7  is captured or latched relative to the fixed guides  3  by the left shift pins  75 , which are partially housed in the through slots  74  in the left wings  73 , partially housed in the left pin seats  32  of the fixed guides  3 , and held in place by the left fork  83  extending over the through slots  74 . This latching prevents any movement of the shift assembly  7 , such as might be caused by vibration, in order to lock the switch machine in this position.  
         [0026]    When it is desired to move the switch points A 1 , A 2  from the right end position toward the left end position, movement of the control rod  8  toward the left part of the drawing, as indicated by the arrow in FIG. 2, is caused by the aforementioned power unit. This movement of the control rod  8  first forces the left end stroke stabilizing pin  66  upwardly out of the left semi-cylindrical groove  82  into the left recess  65 , allowing the control rod  8  to move leftward. In FIG. 3, shortly after this movement toward the left is initiated, it can be seen that the inner edge of the right fork  81  is abutting the right shift pins  75  which in turn exert a force to the left on the left walls of the through slots  74  in the right wings  73  of the assembly  7 . Further, the region over each left shift pin  75  is cleared by the displacement of the left fork  83  toward the left. It is at this point that the shift assembly  7  and the skate  6  are unlatched, and they can begin to move to the left relative to the fixed guide  3 , in response to the force exerted by the right fork  81 . Because of the extended length of the left ball slot  61 , the control rod  8 , the skate  6 , and the shift assembly  7  can all move to the left relative to the left operating rod  4 , even though the right ball  42  is still capturing the right operating rod  5  in place. As the shift assembly  7  moves to the left, the left shift pins  75  are pushed up the sloping left walls of the left pin seats  32  by the right walls of the through slots  74  in the left wings  73 , until the shift assembly  7  is completely disengaged from the fixed guides  3 .  
         [0027]    As the control rod  8  continues to move to the left, the right fork  81  pushes the shift assembly  7  and the skate  6  to the left, with respect to the operating rods  4 ,  5 , with the result that the right ball  42  is eventually expelled, by gravity and the spring  22 , from the right ball seat  24  into the right ball slot  62  in the upper side of the skate  6 . This releases the right operating rod  5  from the fixed plate  2 ; at the same time, the left ball  42  runs along the whole length of the left ball slot  61  on the skate  6 . This sequence of movements, all initiated by the movement of the control rod  8  to the left, has the effect of unlocking the operating rods  4 ,  5 , the transverse bar  9 , and the switch points A 1 , A 2  for movement to their respective left positions. Continued leftward movement of the control rod  8 , the shift assembly  7 , and the skate  6  pushes the left operating rod  4  to the left, because of the left ball  42  being abutted by the right wall of the left ball slot  61  and captured in the left ball slot  61  by the fixed plate  2 . This configuration is shown in FIG. 4. Leftward movement of the operating rods  4 ,  5  continues in this way, displacing the left switch point A 1  and, in turn, the right switch point A 2 , which is connected to the left switch point A 1  by the transverse bar  9 . The switch points A 1 , A 2  are thus moved away from the full right position and toward the left position.  
         [0028]    As seen in FIG. 5, leftward movement has continued until the left switch point A 1  abuts the left stock rail C 1 , and the left ball  42  is positioned directly under the left disk  21  and the left ball seat  24 . This positions the operating rods  4 ,  5  in their full left position.  
         [0029]    At this left end point of the operating rods  4 ,  5 , continued leftward movement of the control rod  8  causes the left ball  42  to be forced upwardly against the disk  21 , because of the slope of the right wall of the left ball seat  61  and resistance to further movement of the ball  42  by the left side of the through hole  41 . As the left ball  42  is forced upwardly, it compresses the spring  22 , until the left ball  42  enters the left ball seat  24  as shown in FIG. 6. Once the left ball  42  rises at least partially into the left through hole  41 , it creates an interference which prevents the operating rods  4 ,  5  from moving farther relative to the fixed plate  2 . However, the operating rod  8 , the skate  6 , and the shift assembly  7  can continue moving to the left because of the extended length of the right ball slot  62 , until the right shift pins  75  engage the shift assemby  7  with the right pin seats  32  in the fixed guides  3 .  
         [0030]    The assembly made of the operating rods  4 ,  5 , the transverse bar  9 , and the switch points A 1 , A 2 , is also then captured relative to the fixed plate  2  by the left ball  42 . At this point, the right shift pins  75  have aligned with, and dropped into, the right pin seats  32  in the fixed guides  3 . Also, the right ball  42  has completed its displacement along the right ball slot  62 , and it now abuts the right wall of the right ball slot  62 . This abutment of the right ball  42  with the right wall of the right ball slot  62  has stopped the leftward movement of the skate  6  and the shift assembly  7  relative to the fixed plate  2 . However, the control rod  8  and the forks  81 ,  83  have continued to move leftward until the right shift pins  75  are captured within the right pin seats  32  of the fixed guides  3  by the right fork  81 , securely latching or capturing the shift assembly  7  and the skate  6  relative to the fixed guides  3 . Further, the right end stroke stabilizing pin  66  has dropped partially into the groove  82  on top of the fork  81 , stabilizing the control rod  8  relative to the skate  6 . This locks and latches the switch machine at the full left end of its stroke.  
         [0031]    It can be seen that, in this locked and latched configuration, the control rod  8  is not affected by possible loads which may be exerted on the detached right switch point A 2 . Such loads are transmitted to the switch point A 1  via the transverse bar  9 , and to the operating rod  4 , and they are then absorbed by the plate  2 , to which the left operating rod  4  is captured. Furthermore, since the right fork  81  captures the right shift pins  75  in the right pin seats  32 , this prevents accidental shifting of the switch machine, which could be caused, for example, by vibrations.  
         [0032]    Shifting of the mechanism back to the right is accomplished in a similar fashion to the leftward shifting.  
         [0033]    According to another aspect of the invention, electrical sensors incorporated in locations in the mechanism such as the forks  81 ,  83  act to monitor the correct or incorrect positioning of the mechanism at the right and left end points of its stroke. That is, as can readily be seen from FIG. 2, an electrical sensor in the left fork  83  senses attainment of its rightmost position relative to the left operating rod  4 , at the right end point of the stroke of the switch machine. Similarly, as can readily be seen from FIG. 6, an electrical sensor in the right fork  81  senses attainment of its leftmost position relative to the right operating rod  5 , at the left end point of the stroke of the switch machine. These sensors may be any suitable sensor such as shown for example in U.S. Pat. No. 6,149,106 and may be engageable with the forks  81 ,  83  and the operating rods  4 ,  5 . Alternatively, the sensors may be mounted elsewhere within the switch machine so as to sense the position of one element relative to another element within the switch machine.  
         [0034]    In FIG. 7, a first type of irregular functioning of the switch machine is illustrated, where an obstacle  100  between the left switch point A 1  and the left stock rail C 1  has prevented the full displacement of the switch point A 1  to abut the left stock rail C 1 . The obstacle  100  causes the switch point A 1  to stop advancing, and the displacement of the control rod  8  can not reach the predetermined end-stroke point. It can be seen that a sensor in the right fork  81  will readily indicate that the control rod  8  has not reached the end of its stroke relative to the operating rods  4 ,  5 , so that this type of irregular condition is made evident. This irregular functioning may then be communicated to associated wayside signalling equipment or remotely to a data center communicating with the switch.  
         [0035]    In FIG. 8, a second type of irregular functioning is caused by the absence of the stroke rail C 1  in the correct position. In that case, the displacement of the switch point A 1  is not opposed by the stock rail C 1 ; therefore, the left side of the left through hole  41  never offers sufficient resistance to the movement of the left ball  42  to cause the left ball  42  to react against the sloped wall of the left ball slot  61  and move upwardly, compressing the spring  22  and entering the left ball seat  24 . Therefore, the skate  6  is not released from its engagement with the left operating rod  4 , and the operating rods  4 ,  5  continue to move to the left with the control rod  8 . As in the previous example, it can be seen that a sensor in the right fork  81 , for example, will readily indicate that the control rod  8  has not reached the end of its stroke relative to the operating rods  4 ,  5 , so that this type of irregular condition is made evident. Such event is then communicated to other wayside equipment or a remote data center.  
         [0036]    As can be seen, the described switch machine is highly reliable in any possible condition which can arise either during the normal operation of the device or during abnormal operation.  
         [0037]    While the particular invention as herein shown and disclosed in detail is fully capable of obtaining the objects and providing the advantages hereinbefore stated, it is to be understood that this disclosure is merely illustrative of the presently preferred embodiments of the invention and that no limitations are intended other than as described in the appended claims.