Patent Publication Number: US-11041274-B2

Title: Center supported bond joint

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 13/473,074, filed May 16, 2012, which is a continuation of U.S. patent application Ser. No. 12/479,301, filed Jun. 5, 2009, which is a continuation of U.S. patent application Ser. No. 11/133,167 filed on May 19, 2005, which claims the benefit of U.S. Provisional Application No. 60/573,117 filed on May 21, 2004, which applications are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to insulated rail joint bars for electrically isolating parts of a rail system from each other and, more particularly, to a center support sleeve for a bonded rail joint bar. 
     Description of Related Art 
     A rail system, which permits more than one train to travel on one stretch of track of rail, is generally divided into sections or blocks. The purpose of dividing railroad rails of a rail system into sections is to detect the presence of a train on a section of rail at any given time. Each rail section is electrically isolated from all other sections so that a high electrical resistance can be measured over the rail section when no train is present in that section. When a train enters a rail section, the train will short circuit adjacent railroad rails in which the electrical resistance in the rail section drops, thereby indicating the presence of a train. 
     Railroad rails are generally welded to each other or attached to each other by a steel joint. Referring to  FIG. 1 , a typical railroad rail  10  having a first side  12  and a second side  14  includes a body  16  having a head  18 , a web  20 , and a base  22  having an upper surface  24 . The head  18  is connected to the web  20 , which is connected to the base  22 . A web recess  26  is defined between the head  18  and the base  22  on the first side  12  and the second side  14  of the body  16  of the railroad rail  10 . 
     There are many different types and shapes of rail joint bars.  FIG. 1  shows a typical prior art rail joint bar  30  that can be used to attach railroad rails to each other. The prior art rail joint bar  30  generally includes a body  32  having a front surface  34  and a back surface  36  and defining a head section  38 , a web section  40  and a base section  44 . The head section  38  depends from the web section  40 , which depends from the base section  44 . The web section  40  defines a plurality of holes  42  for receiving fasteners (one hole  42  shown in  FIG. 9 ). The base section  44  having a bottom surface  46  extends away from the front surface  34  of the body  32  of the rail joint bar  30 . The prior art rail joint bar  30  is adapted to be received within the web recess  26  of the railroad rail  10 , wherein the bottom surface  46  of the body  32  of the rail joint bar  30  is adjacent the upper surface  24  of the base  22  of the railroad rail  10 . 
     High-performance, non-metallic rail joint bars are typically used for electrically-isolating adjacent rail sections of a rail system in order to create an electrically-isolated section. However, these non-metallic rail joint bars are very expensive because of the special high-performance material needed to endure the high tensile and flexural forces exerted on a rail joint bar as the wheels of a locomotive or rail car pass over the rail joint bar. These tensile and flexural forces are higher at a center portion of the rail joint bar where the two railroad rails are joined. An alternative to the non-metallic rail joint bar is a steel rail joint bar having electrically-insulating adhesive material A, such as epoxy, bonded to the back surface  36  of the rail joint bar  30  (shown in  FIG. 1 ). However, these epoxies will oftentimes peel off of the bonded rail joint bar  30 , particularly at the center where the tensile and flexural forces are the highest, thereby resulting in a weaker bonded rail joint bar  30  with less electrical insulating capability. It is, therefore, desirable to have a support sleeve positioned between a bonded rail joint bar and where two railroad rails are joined in order to spread the impact loads of the rail cars away from the center portion of the rail joint bar, thus preventing damage to the bonded rail joint bar at this center location. 
     SUMMARY OF THE INVENTION 
     The present invention provides for a center support sleeve for a bonded rail joint bar that includes a body having a head portion, a web portion, and a base portion. The head portion depends from the web portion, which depends from the base portion. The head portion and the base portion are bent in the same direction thereby defining a recess area therebetween. The web portion of the body also defines a plurality of holes or slots. 
     The present invention also provides for a railroad rail assembly that includes two abutting railroad rails and a prior art rail joint bar attached to the abutting railroad rails. An adhesive is sandwiched between a back surface of the rail joint bar and the two abutting railroad rails. A center support sleeve as previously described is sandwiched between a center portion of the back surface of the rail joint bar and the two abutting railroad rails, wherein the support sleeve is adapted to spread the impact loads of rail cars away from the center portion of the rail joint bar. 
     The present invention provides for a method for securing two abutting railroad rails that includes the steps of joining two railroad rails end to end and positioning an electrically-insulating spacer between the ends of the two railroad rails positioned end to end. Next, an adhesive is placed on a surface of a rail joint bar and a center support sleeve is positioned on a center portion of the surface of the rail joint bar. Finally, the rail joint bar having the adhesive and the support sleeve is attached to the railroad rails via a fastener, wherein the support sleeve is sandwiched between the railroad rails and the rail joint bar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side elevational view of a typical prior art rail joint bar co-acting with a railroad rail; 
         FIG. 2  is a perspective view of a center support sleeve made in accordance with the present invention; 
         FIG. 2 a    is a perspective view of other embodiments identified by dashed lines of the center support sleeve shown in  FIG. 2 ; 
         FIG. 3  is an elevational side view of the sleeve shown in  FIG. 2 ; 
         FIG. 4  is an elevational side view of the center support sleeve shown in  FIG. 2  attached to a prior art rail joint bar; 
         FIG. 5  is a perspective view of a center support sleeve made in accordance with a second embodiment of the present invention; 
         FIG. 5 a    is a perspective view of other embodiments identified by dashed lines of the center support sleeve shown in  FIG. 5 ; 
         FIG. 6  is an elevational side view of the sleeve shown in  FIG. 5 ; 
         FIG. 7  is an elevational side view of the center support sleeve shown in  FIG. 5  attached to a prior art rail joint bar; 
         FIG. 8  is an elevational side view of a rail joint assembly made in accordance with the present invention; and 
         FIG. 9  is a sectional view of the rail joint assembly taken along lines IX-IX shown in  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 2-4 , the present invention provides a center support sleeve  50  that is adapted to be sandwiched between a center portion of a prior art rail joint bar  30  and a pair of railroad rails  10 ,  10 ′ (designated as area A 1  shown in  FIG. 8 ). The support sleeve  50  extends partially around the rail joint bar  30  as shown in  FIG. 4  in order to spread the impact loads of the rail cars away from the center portion of the rail joint bar  30 . The sleeve  50 , which has an end profile similar to the back surface  36  of the prior art rail joint bar  30  includes a body  52  having a first end  54  and a second end  56  and defining a head portion  58 , a web portion  60 , and a base portion  62 . The body  52  of the sleeve  50  includes a first surface  64  and a second surface  66 , wherein the head portion  58  depends from the web portion  60 , which depends from the base portion  62 . The head portion  58  and the base portion  62  are bent in a direction toward the first surface  64  of the web portion  60 , thus defining a U-shaped recess area  68  therebetween. The web portion  60  also defines a plurality of holes  61  (shown in  FIG. 2 ) for receiving fasteners. Alternatively, the length of the sleeve  50  may be shortened by removing the sleeve  50  at dashed lines E, thereby removing end portions such that an open-ended hole or slot  61  may be provided therein (shown in  FIG. 2 a   ). As used herein, “holes” means holes and/or open-ended slots. Referring to  FIG. 2 a   , the base portion  62  and a portion of the web portion  60  may also be removed from sleeve  50  (at dashed line C), thereby providing a sleeve with only a head portion  58  and a partial web portion  60 . Further, both the end portions (dashed lines E) and a portion of the web portion  60  (dashed line C) may be removed from sleeve  50 , thereby providing a shortened sleeve having a partial web portion  60 . 
     The sleeve  50  can be made of an electrically-insulating material, such as fiberglass or a polymeric material such as polyurethane. Referring to  FIG. 8 , a sleeve  50  made of fiberglass is preferably used to prevent damage to a center portion of the rail joint bar  30 , by spreading the impact loads of rail cars away from area A 1  of the rail joint bar  30  where the tensile and flexural forces are the greatest. For example, a fiberglass sleeve  50  (e.g., having multiple plies, for example, five plies where adjacent plies strands are arranged transverse to each other) can generally support a load of at least 100,000 psi tensile strength and have a compression strength of at least 70,000 psi. In contrast to a sleeve  50  made of fiberglass, a sleeve  50  made of polyurethane provides a dampening effect in area A 1 , thereby preventing damage to the center portion of the rail joint bar  30  by allowing for greater flexibility in area A 1  of the railroad rails  10 ,  10 ′ than in the areas adjacent A 1  (i.e., lateral portions of rail joint bar  30 ). For example, a polyurethane sleeve  50  having a thickness of about 0.060 inches can generally support a load of at least 6500 psi tensile strength and at least 270 percent elasticity. The thickness and the length of the sleeve  50  can vary, however, the length of the sleeve  50  should be long enough, wherein at least two of the center portion holes  42  of the rail joint bar  30  align with the holes  61  in the sleeve  50 . 
       FIGS. 5-7  show another embodiment of a center support sleeve  70  that is similar to sleeve  50 , except for the differences noted below. Like reference numerals are used for like parts. The first end  54  of the head portion  58  is bent toward the base portion  62  thus forming an arcuate-shaped lip  72  adapted to fit the contour of the head section  38  of the body  32  of the prior art rail joint bar  30  as shown in  FIG. 7 .  FIG. 5 a    also shows other embodiments as represented by dashed lines C, E and C and E, of sleeve  70  similar to the embodiments of sleeve  50  shown in  FIG. 2   a.    
     When two abutting railroad rails  10 ,  10 ′ are joined together using a prior art rail joint bar  30  as shown in  FIG. 8 , a rail bonding adhesive A (shown in  FIG. 1 ), such as an epoxy, is typically interposed between the rail joint bar  30  and the railroad rails  10 ,  10 ′, thereby providing for a stronger and more durable electrically-insulated bond joint. These epoxies, which can be any of the types well known in the art, generally have a shear strength in a range of 3,000 to 4,000 psi and an elasticity ranging from 0.001 to 0.003 inch per inch elasticity. However, because of the high tensile and flexural forces exerted on the railroad rails  10 ,  10 ′, particular at area A 1  (shown in  FIG. 8 ) where the two railroad rails  10 ,  10 ′ are joined, these epoxies will oftentimes peel off of the rail joint bar  30 , resulting in a weaker bonded rail joint bar  30  and less electrical insulating capability. The sleeve  50 , when used in combination with the rail joint bar  30 , may eliminate the need for an epoxy in area A 1 , thus eliminating any potential unzipping of the epoxy from the rail joint bar  30 . 
     Referring to  FIGS. 8 and 9 , the present invention provides for a rail joint assembly  80  that includes a first railroad rail  10  joined to a second railroad rail  10 ′ and having a spacer  82  therebetween. The rail joint assembly  80  further includes two prior art rail joint bars  30 ,  30 ′, wherein rail joint bar  30  is fastened to a first side  12  of the railroad rails  10 ,  10 ′, and rail joint bar  30 ′, which is identical to rail joint bar  30 , is fastened to a second side  14  of the railroad rails  10 ,  10 ′ as shown in  FIG. 9 . A sleeve  50 , as previously described, is sandwiched in area A 1  between the first side  12  of railroad rails  10 ,  10 ′ and rail joint bar  30 , and a second sleeve  50 ′, which is identical to sleeve  50 , is sandwiched in area A 1  between the second side  14  of railroad rails  10 ,  10 ′ and rail joint bar  30 ′. The sleeves  50 ,  50 ′ are positioned intermediate of the ends of the rail joint bars  30 ,  30 ′ (i.e., in area A 1 ). The holes  42  in rail joint bar  30  and the holes  61  in sleeve  50  are aligned with the corresponding holes  42 ′ in rail joint bar  30 ′ and the holes  61 ′ in sleeve  50 ′. A fastener F, such as a bolt, then passes through each corresponding hole  42 ,  42 ′ of rail joint bars  30 ,  30 ′, each corresponding hole  61 ,  61 ′ of sleeves  50 ,  50 ′, and the respective railroad rail  10 ,  10 ′. A nut N can then be threaded or welded at an end of the fastener F. A rail bonding adhesive A made of electrically-insulating material, such as an epoxy, can be dispersed across either the entire back surface  36 ,  36 ′ or only on the lateral portions of the back surface  36 ,  36 ′ of the rail joint bars  30 ,  30 ′, respectively, in order to hold the sleeves  50 ,  50 ′ in place, thus preventing movement of the rail ends due to temperature changes. Also, an adhesive such as an epoxy, silicon or rubber cement, or seal (not shown) can be placed between the sleeves  50 ,  50 ′ and the railroad rails  10 ,  10 ′, respectively, and/or the rail joint bars  30 ,  30 ′ and the sleeves  50 ,  50 ′ in order to prevent shortening of the sleeves  50 ,  50 ′ due to moisture. In the area adjacent area A 1 , the rail joint bars  30 ,  30 ′ may be attached to the railroad rail  10 ,  10 ′ using fiberglass beaded plates such as described in U.S. Pat. No. 5,503,331, which is hereby incorporated by reference in its entirety. 
     The surfaces defining the holes  42 ,  42 ′ in rail joint bars  30 ,  30 ′ can be at least partially surrounded by an electrically insulated bushing  43  (shown in phantom in  FIG. 9 ) to prevent the fasteners F from conducting electric current between the railroad rails  10 ,  10 ′ and the rail joint bars  30 ,  30 ′, thereby assuring electrical insulation of the rail joint assembly  80 . Likewise, washers  45 , when used in conjunction with fasteners F, may also be made of an electrically insulating material. Also, in lieu of the two bushings  43 , a single bushing (not shown) can also be used. 
     The present invention provides for a method of securing two abutting railroad rails  10 ,  10 ′ using prior art rail joint bars  30 ,  30 ′, wherein the abutting railroad rails  10 ,  10 ′ are electrically isolated from one another. First, an end of the first railroad rail  10  is joined to an end of the second railroad rail  10 ′ and an electrically-insulating spacer  82  is positioned therebetween as shown in  FIG. 8 . Second, a rail bonding adhesive A, such as an epoxy, may be dispersed across the back surface  36 ,  36 ′ of the rail joint bars  30 ,  30 ′ or only on the lateral portions of the back surface  36 ,  36 ′ of the rail joint bars  30 ,  30 ′, respectively. Third, a first sleeve  50  is positioned on a center portion of the back surface  36  of rail joint bar  30 , and a second sleeve  50 ′ is positioned on a center portion of the back surface  36 ′ of rail joint bar  30 ′, wherein the holes  61 ,  61 ′ in sleeves  50 ,  50 ′ are aligned with the holes  42 ,  42 ′ in rail joint bars  30 ,  30 ′, respectively. Fourth, rail joint bar  30  having the sleeve  50  is placed on a first side  12  within the web recess  26 , and rail joint bar  30 ′ having the sleeve  50 ′ is placed on a second side  14  within the web recess  26  at the center location (area A 1 ) of the railroad rails  10 ,  10 ′. Next, the rail joint bars  30 ,  30 ′ are attached to the railroad rails  10 ,  10 ′ via fasteners F passing through each corresponding hole  42 ,  42 ′ of rail joint bars  30 ,  30 ′, each corresponding hole  61 ,  61 ′ of sleeves  50 ,  50 ′ and the respective railroad rail  10 ,  10 ′. A nut N can be placed at an end of the fasteners F and tightened. When the sleeves  50 ,  50 ′ are made of polyurethane, it is desirable that the fasteners F be tightened further before the adhesive material A on the rail joint bars  30 ,  30 ′ completely cures after being applied. An adhesive such as epoxy, silicon, or rubber cement (not shown) can also be placed on the first surface  64 ,  64 ′ and the second surface  66 ,  66 ′ of the sleeves  50 ,  50 ′, respectively, before attachment of the rail joint bars  30 ,  30 ′ to the first side  12  and the second side  14  of the railroad rails  10 ,  10 ′, respectively. 
     It will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed in the foregoing description. Accordingly, the particular embodiments described in detail herein are illustrative only and are not limiting to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.