Boot for streetcar rails

Abstract

The extruded rubber boot is wrapped around the rail before the rail is placed in the ground. The boot provides electrical and mechanical isolation of the metal rail from the concrete of the pavement. The boot profile is configured with a double-wall column, which, when hammered in, becomes tightly wedged between the head and the base of the rail. Nothing else (such as adhesive tape wrapped around the boot) is needed in order to hold the boot to the rail during assembly and installation of the rail and pavement.

1 . A wrap-round boot for a rail, wherein: 
 the rail has a rail-profile including a head, a base, and a web connecting therebetween, having the following characteristics: 
 the head has a rail-head-gauge-underface and a rail-head-field-underface;  
 the base-flange has a rail-base-gauge-overface, and a rail-base-field-overface;  
 the rail-head-gauge-overface and the rail-base-gauge-underface are so angled as to define a rail-gauge-wedge-angle therebetween;  
 the rail-head-field-overface and the rail-base-field-underface are so angled as to define a rail-field-wedge-angle therebetween;  
   the boot has a boot-profile including a gauge-portion, a field-portion, and an under-rail-portion connecting the gauge-portion and the field-portion;    the boot is of flexible elastomeric material, being flexible in that the boot can be wrapped around the rail; 
 the boot-profile is so structured as to lie, when wrapped around the rail:  
 with the under-rail-portion underneath the base of the rail;  
 with the gauge-portion wedged into the rail-gauge-wedge-angle; and  
 with the field-portion wedged into the rail-field-wedge-angle.  
   
   
   
       2 . Boot of  claim 1 , wherein: 
 the gauge-portion of the boot-profile includes a boot-head-gauge-underface-portion, a boot-base-gauge-overface-portion, and a boot-web-gauge-portion connecting therebetween;    the field-portion of the boot-profile includes a boot-head-field-underface-portion, a boot-base-field-overface-portion, and a boot-web-field-portion connecting therebetween;    
   
   
       3 . Boot of  claim 1 , wherein the material of the boot is extruded.  
   
   
       4 . Boot of  claim 1 , wherein the material of the boot is rubber.  
   
   
       5 . Boot of  claim 1 , wherein a boot-web-portion of the boot is of double-wall configuration.  
   
   
       6 . Boot of  claim 1  in combination with the rail, wherein: 
 the boot lies wrapped around the rail: 
 with the under-rail-portion underneath the base of the rail;  
 with the gauge-portion wedged into the rail-gauge-wedge-angle; and  
 with the field-portion wedged into the rail-field-wedge-angle.  
   
   
   
       7 . Combination of  claim 6 , wherein: 
 the boot-head-gauge-underface-portion lies wedged in contact with the rail-head-gauge-underface;    the boot-base-gauge-overface-portion lies wedged in contact with the rail-base-gauge-overface;    the boot-head-field-underface-portion lies wedged in contact with the rail-head-field-underface;    the boot-base-field-overface-portion lies wedged in contact with the rail-base-field-overface.    
   
   
       8 . Combination of  claim 6 , wherein: 
 the web of the rail has a gauge-side and a field-side;    the boot-web-gauge-portion of the boot lies clear of contact with the gauge-side of the web; and    the boot-web-field-portion of the boot lies clear of contact with the field-side of the web.    
   
   
       9 . Combination of  claim 6 , wherein: 
 a rail-vertical-line is a line joining an upper-mid-point of the rail-head-underface to a lower-mid-point of the rail-base-overface;    a boot-vertical-line is a line drawn in the material of the boot, which overlies the rail-vertical-line when the boot lies wedged into the rail;    the structure of the boot is such that, when the boot is withdrawn clear of the rail, whereby the material thereof is no longer compressed, the length of the boot-vertical-line expands by an increment; and    the increment is more than about two millimetres.    
   
   
       10 . Combination of  claim 6 , wherein: 
 a boot-web-portion of the boot comprises a column;    the configuration of the boot is such that the column is under compressive stress when the boot lies wedged into the rail;    the column is so configured that, when the boot is wedged in the rail, the column is of a shape that is between straight and slightly convex, being only so slightly convex that the wedged-in column is stressed in compression, rather than in bending or buckling.    
   
   
       11 . Combination of  claim 6 , wherein: 
 an IEU point is a point of innermost extremity of the contact between the upper end of the column and the rail-head-underface;    an IEL point is a point of innermost extremity of the contact between the lower end of the column and the rail-base-overface;    an IEU-IEL line is a line joining the IEU point to the IEL point;    the column is so configured that there is compression-stressed boot material on both sides of the IEU-IEL line, being material that is stressed by compressive forces in the column.    
   
   
       12 . Boot of  claim 1 , wherein a boot-web-portion of the boot is of single-wall configuration.  
   
   
       13 . Boot of  claim 1 , wherein: 
 a boot-web-portion of the boot comprises a column;    the configuration of the boot is such that the column is under compressive stress when the boot lies wedged into the rail;    the column is so configured that, when the boot is wedged in the rail, the column is of such shape that the wedged-in column is stressed in compression, rather than in bending or buckling.    
   
   
       14 . Boot of  claim 13 , wherein the column includes a portion thereof that is in the form of a cell or pocket, which is so configured as to cause the vertical compressive stresses arising in the column to be distributed evenly over a large area of the rail.