Device for throwing a switch point

Abstract

A rail support forms an upwardly directed generally planar slide face, a longitudinally extending running rail secured to the support and having a foot. A longitudinally extending switch blade adjacent the rail is shiftable above the slide face between an inner position closely transversely juxtaposed with the running rail and an outer position transversely spaced from the running rail. A frame defines a longitudinal outer axis spaced transversely along the slide face from the running rail, a longitudinal middle axis between the outer axis and the running rail, and an inner axis between the middle axis and the running rail. Respective outer, middle, and inner rollers are carried on the frame and rotatable about the respective axes. The middle roller is axially offset from the inner and outer rollers and is of such a diameter that it radially overlaps the inner and outer rollers.

1 . In combination with
 a rail support forming an upwardly directed generally planar slide face;   a longitudinally extending running rail secured to the support and having a foot with a predetermined transverse width;   a longitudinally extending switch blade adjacent the rail and shiftable above the slide face between an inner position closely transversely juxtaposed with the running rail and an outer position transversely spaced from the running rail, a device comprising   a frame defining a longitudinal outer axis spaced transversely along the slide face from the running rail, a longitudinal middle axis between the outer axis and the running rail, and an inner axis between the middle axis and the running rail;   respective outer, middle, and inner rollers carried on the frame and rotatable about the respective axes, the middle roller being axially offset from the inner and outer rollers and being of such a diameter that it radially overlaps the inner and outer rollers.   
   
   
       2 . The device defined in  claim 1  wherein the axes are transversely spaced and the rollers have outer peripheries of such diameter that a spacing between the outer periphery of the middle roller and the outer periphery of each of the inner and outer rollers on a plane of the slide face is less than the transverse width of the switch-blade foot. 
   
   
       3 . The device defined in  claim 1 , further comprising
 means for vertically shifting the middle axis and roller relative to the slide face.   
   
   
       4 . The device defined in  claim 1  wherein the frame is a single plate supporting the inner, middle, and outer rollers. 
   
   
       5 . The device defined in  claim 1  wherein the frame is shiftable transversely of the running rail. 
   
   
       6 . The device defined in  claim 1  wherein the uppermost extent of the outer periphery of the inner roller is below the uppermost extent of the outer periphery of the outer roller. 
   
   
       7 . The device defined in  claim 6  wherein the uppermost extent of the outer periphery is above that of the inner roller and above that of the outer roller. 
   
   
       8 . The device defined in  claim 7  wherein the outer peripheries of the rollers define a plane on which the foot of the switch blade sits and that is inclined at a small acute angle downward toward the running rail. 
   
   
       9 . The device defined in  claim 1  wherein the frame is also displaceable on the support between an innermost position juxtaposed closely with the running rail and an outermost position spaced well outward from the running rail, the foot of the switch blade being between the inner roller and the running rail and resting on the slide face in the innermost position of the frame.