Patent Publication Number: US-8123144-B2

Title: Rail joint bars and rail joint assemblies

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 11/503,865, filed Aug. 14, 2006, now U.S. Pat. No. 7,490,781, which is a divisional of U.S. patent application Ser. No. 10/838,172, filed May 3, 2004, now U.S. Pat. No. 7,090,143, which claims the benefit of U.S. Provisional Patent Application No. 60/467,451, filed May 2, 2003, all of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a rail joint bar and a rail joint assembly for electrically-isolating sections of rail in a rail system. Particularly, the present invention relates to rail joint bars secured by fasteners to abutting rails of a rail system for creating a rail joint having an electrically-insulating spacer between the rail joint bars and rails, and gaskets between ends of the adjacent railroad rails, all for electrically-isolating adjacent rail sections of a rail system. 
     2. Description of Related Art 
     A rail system, which permits more than one train to travel on one stretch of track or rail, is generally divided into sections or blocks. The purpose of dividing rails of a rail system into sections is to detect the presence of a train on a section of rail at any given time. Rail sections of a rail system are electrically isolated from each other to measure a high electrical resistance over the rail section in the absence of a train on any rail section of the system. Upon entry onto a rail section, a train will short circuit adjacent railroad rails in a rail section and the electrical resistance will drop to indicate the presence of the train in the rail section. 
     Railroad tracks are created generally by welding railroad rails to each other or attaching railroad rails to each other with a steel joint. High-performance, non-metallic joints are typically used for electrically-isolating adjacent rail sections of a rail system in order to create an electrically-isolated section. However, the non-metallic joints are very expensive due to the special high-performance material needed to endure the high tensile and flexural forces exerted on a rail joint as the wheels of a locomotive or rail car pass over the joint. An alternative to a non-metallic joint is a steel rail joint having electrically-insulating material, such as epoxy affixed to the rail joint surface for isolating rail sections. However, these epoxies must be able to endure the high tensile and flexural forces exerted on the railroad rails in order to prevent the electrically-insulating material from peeling off the rail joint. It is, therefore, an object of the present invention to provide a rail joint bar that uses two different types of epoxies whereby the above drawbacks are eliminated. 
     During creation of a rail system, an electrically-insulated gasket is typically inserted between the ends of adjacent railroad rails when the rails are joined using a rail joint to provide for further electrical isolation of a rail section. The gaskets are usually made of a material that cannot be compressed, such as fiberglass or a polymeric-based material. The gasket is used to environmentally seal the rail ends. Often times, water penetrates between the gasket and the railroad rail ends, thereby compromising the integrity of the material, which unzips, allowing contact between the electrically-isolated railroad rail sections. It is, therefore, an object of the present invention to provide a compressible gasket that overcomes the above problems. 
     SUMMARY OF THE INVENTION 
     The present invention provides a rail joint created by compressing a compressible gasket between ends of two adjacent railroad rails secured together with the rail joint bars and fasteners creating an electrically-insulated barrier. 
     The present invention provides a rail joint bar having a metal body having an upper end, a lower end, a first surface and a second surface and a defining peripheral edge. An optional cutout or easement can be defined on the upper end and/or lower end of the body. At least the first surface and, optionally, the second surface of the body is peened. The first surface of the metal body coacts with an electrically-insulating spacer, which is a non-metallic mesh screen affixed to the first surface of the body. A layer of an adhesive in the form of an epoxy covers both the mesh screen and the first surface of the body. The layer of adhesive used in the insulating layer can include at least two different types of epoxies. A more rigid type of epoxy is uniformly applied on the lateral portions of the first surface of the rail joint. A less rigid and more elastic epoxy is uniformly applied to the central portion of the first surface of the rail joint bar. A plurality of holes is defined on the rail joint bar and is adapted for receiving fasteners used to secure the rail joint bars to the railroad rails in a manner that the layer of epoxy of each rail joint bar contacts a surface of the railroad rail. 
     The present invention also provides a compressible gasket positioned between the ends of abutting railroad rails secured together by the rail joint bars. The gasket is preferably made of compressible polyurethane having a T-shaped design corresponding to the end of a railroad rail. Alternatively, the gasket is a deformed O-ring gasket that is shaped similar to an end of a railroad rail. During assembly of the rail joint, either gasket is compressed between the ends of the adjacent railroad rails by force exerted on the railroad rails. 
     The present invention provides for a rail joint assembly that includes a pair of abutting railroad rails having a gasket compressed therebetween and a pair of rail joint bars as previously described secured to the pair of railroad rails by fasteners. The electrically-insulating spacers are positioned between the first rail joint bar and the second rail joint bar resting against the first side and the second side of the abutting railroad rails, respectively. Spacers positioned between each rail joint bar and surfaces of the abutting railroad rails provide a uniform distance between the rail joint bars and the sides of the abutting railroad rails so that the layer of epoxy has a generally even thickness between the rail joint bars and the railroad rail. The assembly further includes a plurality of holes defined on the rail joint bars wherein a plurality of fasteners is used to secure the pair of rail joint bars to the abutting railroad rails via holes in the rails. Cylindrical gaskets are optionally provided inside the plurality of holes of the rail joint bars. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a top plan view of a rail joint bar made in accordance with the present invention; 
         FIG. 2  is an elevational side view of a rail joint assembly utilizing the rail joint bar shown in  FIG. 1 ; 
         FIG. 3  is a sectional view of the rail joint assembly taken along lines III-III in  FIG. 2 ; 
         FIG. 4  is a top plan view of a second embodiment of a rail joint bar having a cutout made in accordance with the present invention; 
         FIG. 5  is a elevational side view of a rail joint assembly utilizing the rail joint bar shown in  FIG. 4 ; 
         FIG. 6  is a sectional view of the rail joint bar taken along lines VI-VI shown in  FIG. 5 ; 
         FIG. 7  is a front elevational view of a gasket made in accordance with a first embodiment of the present invention; 
         FIG. 8  is a front elevational view of an O-ring gasket made in accordance with a second embodiment of the present invention; 
         FIG. 9  is a front elevational view of a gasket arrangement made in accordance with another embodiment of the present invention; 
         FIG. 10  is a side elevational view of the gasket arrangement shown in  FIG. 9 ; 
         FIG. 11  is a front elevational view of a gasket arrangement made in accordance with another embodiment of the present invention; and 
         FIG. 12  is a side elevational view of the gasket arrangement shown in  FIG. 11 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referencing  FIGS. 1 and 2 , the present invention is a rectangular-shaped rail joint bar  10  that includes an electrically-insulating layer  12  bonded to a metal body  14 . A plurality of holes  16  (shown in phantom) is defined on the rail joint bar  10 , wherein the plurality of holes  16  is adapted to receive fasteners  18  for securing the rail joint bar  10  to two adjacent railroad rails  30 ,  30 ′. Referencing  FIGS. 1 and 2 , the body  14  having an upper end  15 , a lower end  15 ′, a first surface  20  and a second surface  22  is manufactured from metal material, such as steel or similar strength metal. 
     Referencing  FIGS. 1 and 3 , the insulating layer  12  on the rail joint bar  10  is affixed to or coacts with the first surface  20  of the body  14 . The first surface  20  of the body  14  can be peened to create a more secure attachment of the insulating layer  12 . Optionally, the first surface  20  and/or the second surface  22  of the body  14  is peened. In reference to the present invention, the word “peened” means dimpled or roughened through a peening process that is known in the art. The insulating layer  12  includes a porous member such as a mesh screen  24  affixed to the first surface  20  of the body  14 . An electrically-insulating epoxy  26  covers both the mesh screen  24  and the first surface  20  of the body  14 . The mesh screen  24 , typically made of non-metallic, electrically-insulating material such as fiberglass or plastic, is used to facilitate a uniform dispersion of the epoxy  26  evenly across the first surface  20  of the body  14 . Preferably, an epoxy layer  26  is provided on opposite sides of the mesh screen  24  as shown in  FIGS. 1 and 3 . The surfaces defining the plurality of holes  16  of the rail joint bar  10  can be electrically insulated via bushings. 
     Referencing  FIGS. 1 and 2 , the first surface  20  of the rail joint bar  10  is divided into three (3) separate areas designated as A 1 , A 2  and A 3 . The epoxy  26  forming the insulating layer  12  can include two different types of epoxies having different physical characteristics. A first type of epoxy used in areas A 1  and A 2  is characteristically more rigid, having a higher durometer reading, i.e., durometer hardness, than a second type of epoxy used in area A 3 . The first epoxy or adhesive  26  is dispersed across the first surface  20  of the body  14  on lateral portions A 1  and A 2  of the first surface  20  and the second epoxy or adhesive  26  on a central portion A 3  of the first surface  20  between portions A 1  and A 3 . The second type of epoxy used in area A 3  allows for greater flexibility in area A 3  of railroad rails  30 ,  30 ′ than in areas A 1  and A 2 , because the flexural and tensile forces exerted on the railroad rails  30 ,  30 ′ is greater in area A 3  than in areas A 1  and A 2  when a locomotive and railcars pass over the rail joint assembly. The two different types of epoxy  26  used in the insulating layer  12  result in a more durable rail joint bar  10  when joining two railroad rails  30 ,  30 ′ as shown in  FIG. 2 . The approximate mechanical property values of the first type of epoxy  26  for areas A 1  and A 2  are approximately 3500 psi or greater, and preferably 3800 psi, tensile strength, and preferably at least 0.001, but preferably between 0.001-0.002, inch per inch elasticity. In comparison, the approximate mechanical property values of the second type of epoxy  26  for area A 3  are preferably at least 2000 psi tensile strength, and preferably within the range of 2000-3100 psi (and preferably 2500 psi) tensile strength, and at least 0.003, but preferably within the range of 0.003-0.006 (and more preferably 0.0045), inch per inch elasticity. Such epoxies are manufactured by Lord Corporation, Thermoset Division. 
       FIGS. 2 and 3  show a rail joint assembly  28  used in joining abutting railroad rails  30 ,  30 ′ together. The first railroad rail  30  having a first railroad rail end  32  and a second railroad rail  30 ′ having a second railroad rail end  32 ′ are T-shaped and have a first side  34 ,  34 ′ and a second side  36 ,  36 ′, respectively. The first railroad rail end  32  of the first railroad rail  30  is joined to the second railroad rail end  32 ′ of the second railroad rail  30 ′ via rail joint bars  10 ,  10 ′ shown in  FIG. 3 . Gasket  38  is shown between the first railroad rail end  32  and the second railroad rail end  32 ′. Gasket  38  also has a T-shaped design corresponding to the T-shaped design of the railroad rails  30 ,  30 ′ as shown in  FIG. 7 . Gasket  38  can be made of a compressible, electrically-insulating material, such as polyurethane or rubber. Prior art electrically-insulating spacers looked like gasket  38  except they were made of an electrically-insulating material that was substantially incompressible, such as fiberglass. The railroad rails  30 ,  30 ′ are positioned relative to each other so that the gasket  38  is compressed, thus preventing water from penetrating between the railroad rail ends  32 ,  32 ′. Also, a machine can pre-compress the gasket  38  so the railroad rails  30 ,  30 ′ are at a fixed distance. For example, an eight-ton compression machine can be used to compress the gasket  38  to a fixed width, such as 0.060 inch. The compressed gasket  38  overcomes the problem that arises when water penetrates a non-compressible gasket, such as a fiberglass or polymeric-based gasket, and the gasket material begins to unzip, thereby compromising the electrical isolated nature of the railroad rails. 
     In further reference to  FIGS. 2 and 3 , the rail joint assembly  28  includes two rail joint bars  10 ,  10 ′ attached to railroad rails  30 ,  30 ′.  FIG. 3 , which is a sectional view of  FIG. 2  taken at lines III-III, shows the rail joint assembly  28  with the rail joint bars  10 ,  10 ′ attached to the first railroad rail  30 . Rail joint bar  10  is fastened to the first side  34  of the first railroad rail  30 , and the rail joint bar  10 ′, which is identical to rail joint bar  10 , is fastened to the second side  36  of the first railroad rail  30 . Rail joint bar  10 ′ also has an electrically-insulating layer  12 ′ affixed to a metal body  14 ′ and a plurality of holes  16 ′ defined on the rail joint bar  10 ′. Each of the plurality of holes  16  in rail joint bar  10  is aligned with the corresponding slot  16 ′ in rail joint bar  10 ′. Washer-shaped spacers  40  having a spacer slot  42  for receiving fasteners  18  is positioned between the insulating layers  12 ,  12 ′ of rail joint bars  10 ,  10 ′ and the first side  34  and the second side  36  of the first railroad rail  30 , respectively. Each spacer  40  is made of an electrically-insulating material, such as fiberglass or plastic. The spacer slot  42  in each spacer  40  is aligned with the holes  16 ,  16 ′ in rail joint bars  10 ,  10 ′, respectively. In this arrangement, the mesh screen  24  may be eliminated. A fastener  18 , such as a bolt, is placed through each corresponding slot  16 ,  16 ′ of rail joint bars  10 ,  10 ′ via spacers  40  and the first railroad rail  30 . The spacers  40  enable the insulating layers  12 ,  12 ′ on rail joint bars  10 ,  10 ′ to maintain their uniformity whenever the rail joint bars  10 ,  10 ′ are fastened to the railroad rails  30 ,  30 ′ as shown in  FIG. 2 . This uniformly prevents a portion of the respective insulating layers  12 ,  12 ′ on rail joint bars  10 ,  10 ′ from being crushed, which can result in the insulating layers  12 ,  12 ′ being stripped from the respective bodies  14 ,  14 ′, thus compromising the electrical isolation of the railroad rail sections. The fastener  18  can have threads at one end for receiving a nut  46 . The nut  46  can either be threaded or welded to the fastener  18 . 
       FIGS. 4-6  show a second embodiment of a rail joint bar  11  that is similar to rail joint bar  10 , except that a cutout recessed portion or easement  21  is defined on the upper end  15  of the body  14 . The character references used in  FIGS. 1-3  also identify like parts in  FIGS. 4-6 . A cutout or easement  21 ′ can also be defined on the lower end  15 ′ of the body as shown in  FIGS. 5 and 6 . Referring to  FIGS. 4 and 5 , the cutouts  21 ,  21 ′, located at the center or intermediate section of the body  14 , typically extend a portion of the length of the body  14  in area A 3 , but can also extend into areas A 1  and A 2  (not shown). Hence, a width of the intermediate section having the cutouts  21 ,  21 ′ as defined between the upper end  15  and lower end  15 ′ is less than the width at the remainder of the body  14 . The depth D of the cutouts  21 ,  21 ′ (shown in  FIG. 6 ) can range from 0.060 to 0.080 inch, which is typically below the decarb zone on the surface of a steel plate. 
     Referring to  FIGS. 4 and 5 , the cutouts  21 ,  21 ′ defined on the body  14  allow for more epoxy  26  to be used at the center of rail joint bar  11  than in rail joint bar  10 , as previously shown in  FIGS. 1-3 , because the epoxy  26  flows and sets on top of the cutouts  21 ,  21 ′ as shown by arrows A′. Because the epoxy  26  is deeper in the cutouts  21 ,  21 ′ of rail joint bar  11 , the epoxy  26  is less likely to crack and separate due to fatigue of the rail joint bar  11 . Also, the cutouts  21 ,  21 ′, which are typically below the decarb zone of the body  14 , allow for better adhesion of the epoxy  26  to the upper end  15  and lower end  15 ′, respectively, of the body  14 , thus eliminating possible unzipping of the epoxy  26  from the railroad rails  30 ,  30 ′. 
       FIG. 8  shows a gasket  44  made in accordance with a second embodiment of the present invention. Gasket  44  can be an O-ring-like or ring-shaped gasket having a circular cross-section that has been formed to fit the shape of the railroad rail end  32  of the first railroad rail  30 . Gasket  44  can be made of a compressible, electrically-insulating material, such as polyurethane or rubber. Gasket  44  can also be pre-compressed in a manner similar to gasket  38 . 
     More preferably, in another embodiment as shown in  FIGS. 9 and 10 , two gaskets  44  made of a compressible electrically-insulating material, such as polyurethane or rubber, are provided on opposite sides of and coact with a T-shaped insulated spacer  46 , which can be made of fiberglass or other electrically-insulating material. Preferably, the material of spacers is substantially incompressible. Preferably, a receiving groove  48  is found on each face surface  47  of the spacer  46  (of which one is shown). A portion of the gasket  44  extends from each face surface  47  of the T-shaped spacer. The gaskets  44  are compressed in the same manner as gasket  38 . The spacer  46  has a profile similar to that of the shape of rail ends (also shown in  FIG. 8 ) and has a body with a head H or horizontal member, a web W and a base B. 
       FIGS. 11 and 12  show another embodiment similar to that shown in  FIGS. 9 and 10 , wherein gaskets  60  are positioned on opposite faces  62  of and coact with a T-shaped substantially incompressible insulation spacer  64 . Grooves  66  are found on each face  62  for receipt of the gaskets  60  made of a compressible, electrically-insulating material, such as rubber or polyurethane. The gaskets  60  are substantially convex shaped, hat shaped or arcuate shaped and may extend across or substantially across the entire horizontal member  68  of the spacer  64  (as shown by gasket  60 ′ shown in phantom). Portions of the gaskets  60  extend from face surfaces  67 . The purpose of this arrangement, which is sandwiched between adjacent rail ends, is to insulate adjacent rails and prevent and deflect water  70  from penetrating the web portion W of the spacer  64  positioned between two adjacent rails. Further, for the purposes used herein, the spacer  64  is incompressible relative to the gaskets  44  and  60 . The gaskets  60  can have a circular cross-section. 
     While the present invention is satisfied by embodiments in many different forms, there is shown in the drawings and described in detail herein the preferred embodiments of the invention, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. Various other embodiments will be apparent to and readily made by those skilled in the art without departing from the scope and spirit of the invention. The scope of the invention will be measured by the appended claims and their equivalents.