Patent Publication Number: US-11384485-B2

Title: Rail clip assembly and snap lock toe insulator for same

Description:
TECHNICAL FIELD 
     The present disclosure relates generally to fastening track rail, and more particularly to a rail clip assembly having a toe insulator with a rail contact pad and a snap lock to enable locking or unlocking the toe insulator to a rail clip. 
     BACKGROUND 
     Track rail fastening systems are used the world over, and range in complexity from simple metal plates and clips or clamps, to composite structures employing multiple metallic body components and overmolded polymeric materials for vibration mitigation and cushioning. In many systems, a device known as a rail clip is used to clamp a section of track rail to a pad or pad assembly. Rail clips are typically positioned at intervals along both sides of a section of track rail. 
     So-called E-clips or the like are used in some systems as rail clips, and may include a shaft or shank portion that is received within a bore in a track rail fastener oriented generally along a length of the track rail. A clamping portion extends onto and exerts a downward clamping force against a base portion of a section of the track rail. Other systems employ clips that are more or less C-shaped and include a base end inserted into a laterally extending recess in a fixed shoulder cast in place in an underlying concrete substrate. An end or toe portion commonly equipped with a non-metallic insulator clamps down upon the base portion of a section of the track rail. One example rail clip mechanism is known from Japanese Patent Publication No. JPH0747422Y2. While the concept set forth in this disclosure may have various applications, there is always room for improvement and/or alternative strategies. 
     SUMMARY OF THE INVENTION 
     In one aspect, a rail clip assembly includes a rail clip having a base end, a toe end, a middle spring section having a recurving shape and extending between the base end and the toe end, and an outer clip surface and an inner clip surface each formed in part upon the base end, the toe end, and the middle spring section. An insulator bore is formed in the toe end and opens at each of the outer clip surface and the inner clip surface. The rail clip assembly further includes a toe insulator having a pad with an inner pad surface in contact with the inner clip surface, an outer pad surface having a rail contact face oriented diagonally relatively to the toe end, and a locating projection extending upwardly from the inner pad surface through the insulator bore and including a first engagement surface. The toe insulator further includes a snap lock, the snap lock having an insulator retention surface facing the outer clip surface at locations outboard of the insulator bore, and a second engagement surface. The second engagement surface is in contact with the first engagement surface, such that the snap lock is in a locked configuration trapping the locating projection within the insulator bore, and is adjustable to an unlocked configuration where the locating projection is removable from the insulator bore for decoupling the toe insulator from the rail clip. 
     In another aspect, a rail clip assembly includes a rail clip having a base end, a toe end, a middle spring section having a recurving shape and extending between the base end and the toe end, and an insulator bore formed in the toe end. The rail clip assembly further includes a toe insulator including a pad with an inner pad surface in contact with the toe end, an outer pad surface having a rail contact face oriented diagonally relative to the toe end, and a locating projection extending upwardly from the inner pad surface through the insulator bore. The toe insulator further includes a snap lock, separate from the pad, and structured to engage with the locating projection in a locked configuration trapping the locating projection in the insulator bore and locking the toe insulator to the rail clip. The snap lock is deformable in opposition to an internal bias to adjust the toe insulator to an unlocked configuration permitting disengagement of the toe insulator from the rail clip. 
     In still another aspect, a toe insulator for a rail clip includes a pad having an inner pad surface, an outer pad surface with a rail contact face, and a locating projection extending upwardly from the inner pad surface and including a first engagement surface. The pad further includes a plurality of inner peripheral surfaces forming, together the inner pad surface, an open-sided pocket for receiving a toe end of a rail clip. The toe insulator further includes a snap lock having an insulator retention surface facing the inner pad surface at locations outboard of the locating projection, and a downwardly projecting prong including a second engagement surface. The toe insulator further includes an axially extending lock bore formed in the locating projection, and the downwardly extending prong is positionable in the axially extending lock bore to contact the second engagement surface to the first engagement surface. The downwardly projecting prong is deformable in opposition to an internal bias to adjust the toe insulator from a locked configuration, where the second engagement surface is in contact with the first engagement surface for trapping the locating projection within an insulator bore in the rail clip, to an unlocked configuration where the snap lock is separable from the pad and the locating projection is removable from the insulator bore. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partially sectioned diagrammatic view of a rail fastening system fastening a track rail, according to one embodiment; 
         FIG. 2  is an isometric view of a rail clip assembly, according to one embodiment; 
         FIG. 3  is another isometric view of a rail clip assembly, according to one embodiment; 
         FIG. 4  is yet another an isometric view of a rail clip assembly, according to one embodiment; 
         FIG. 5  is a partially sectioned back side view of a rail clip assembly, according to one embodiment; 
         FIG. 6  is a diagrammatic view of a pad for a toe insulator, according to one embodiment; 
         FIG. 7  is a sectioned view through the pad of  FIG. 6 ; 
         FIG. 8  is another sectioned view through the pad of  FIGS. 6 and 7 ; 
         FIG. 9  is a diagrammatic view of a snap lock for a toe insulator, according to one embodiment; 
         FIG. 10  is a sectioned view through the snap lock of  FIG. 9 ; 
         FIG. 11  is a diagrammatic view of a rail clip assembly in a rail fastening system, in one configuration; and 
         FIG. 12  is a diagrammatic view of a rail clip assembly in a rail fastening system in another configuration. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , there is shown a track rail fastening system  10  fastening a track rail  8  to a substrate  12 , such as a concrete tie. Track rail fastening system  10  includes a rail pad assembly  14  including a pad  16  with track rail  8  supported thereon. Pad  16  can be positioned upon an abrasion plate  18  in contact with substrate  12 . Abrasion plate  18  may be generally flat and planar with upwardly projecting side posts  20  upon either side, and integrated as a single molded or fabricated piece. Shoulders  22  may be positioned upon either side of and coupled with side posts  20 . Those skilled in the art will envision other rail pad assembly configurations that might suitably be applied in the present context. Track rail  8  includes upper surfaces  9  oriented generally diagonally to a horizontal plane, and track rail fastening system  10  further includes a rail clip assembly  30  positioned upon each of opposite sides of track rail  8  and supported within shoulders  22 . Shoulders  22  may be cast in place within concrete material or the like of substrate  12 , although the present disclosure is not thereby limited. As will be further apparent from the following description, each rail clip assembly  30 , which may be substantially identical to one another and hereinafter referred to in the singular, may be structured for improved performance and serviceability as compared with certain known rail clip assembly designs. 
     Rail clip assembly  30  includes a rail clip  32  formed, for example, of an elongate substantially rectangular plate bent to a desired configuration, and having a base end  34  terminating at a base tip  36 , a toe end  38  terminating at a toe end tip  40 , and an arcuate middle spring section  42 . Each of base end  34  and toe end  36  may be substantially straight, and together with middle spring section  42  form profiles similar to a question mark. A bend  44  transitions between middle spring section  42  and toe end  38  and orients toe end  38  to project toward track rail  8  relatively further than the projection of base end  34 . Middle section  42  has a recurving shape and extends between base end  34  and toe end  36 . Rail clip  32  further includes an outer clip surface  46  and an inner clip surface  48  each formed in part upon base end  34 , toe end  38 , and middle spring section  42 . An insulator bore  50  is formed in toe end  38  and opens at each of outer clip surface  46  and inner clip surface  48 . 
     Referring also now to  FIGS. 2-5 , rail clip assembly  30  further includes a toe insulator  52  formed, for example, of a non-metallic material such as an elastomeric material, a rubber or rubber-like material, or still another. In some embodiments toe insulator  52  could include a metallic core encased, partially encased, or coated with a non-metallic material. Toe insulator  52  includes a pad  54  having an inner pad surface  56  in contact with inner clip surface  48 , and an outer pad surface  58  having a rail contact face  60  oriented diagonally relative to toe end  38 . Pad  54  may also include inner peripheral surfaces  84  bordering inner pad surface  56 , such as upon three sides, and forming an open-sided pocket  86  receiving toe end  38  of rail clip  32 . Pad  54  may also include a locating projection  62  extending upwardly from inner pad surface  56  through insulator bore  50  and including a first engagement surface  64 . 
     Toe insulator  52  further includes a snap lock  66 . Snap lock  66  may include a plate  76 , and an insulator retention surface  68  upon plate  76 . Insulator retention surface  68  faces outer clip surface  46 , and faces inner pad surface  56 , at locations outboard of insulator bore  50 . In this context, “outboard” is used in reference to insulator bore  50  and means away from insulator bore  50  in any radial direction, whereas “inboard” means an opposite direction or orientation. Snap lock  66  includes a second engagement surface  70 . Second engagement surface  70  is in contact with first engagement surface  64 , in  FIGS. 1, 2, 4, and 5 , such that snap lock  66  is in a locked configuration trapping locating projection  62  with insulator bore  50 . Snap lock  66  is removed in the illustration of  FIG. 3 . Snap lock  66  is adjustable to an unlocked configuration where locating projection  62  is removable from insulator bore  50  for decoupling toe insulator  52  from rail clip  32 . Pad  54  and snap lock  66  may be separate pieces disconnected in the unlocked configuration, although the present disclosure is not thereby limited. Plate  76  may include outer peripheral surfaces  82  forming a rectangular shape. In the illustrated embodiment, a clearance  88  extends between outer peripheral surfaces  82  and inner peripheral surfaces  84 . 
     Referring also now to  FIGS. 6-8 , locating projection  62  defines a projection axis  72 , and has formed therein an axially extended lock bore  74 . First engagement surface  64  and second engagement surface  70  may each have transverse orientations relative to projection axis  72  and are within axially extending lock bore  74  in the locked configuration. Insulator bore  50  may be cylindrical, and axially extending lock bore  74  may be non-cylindrical, for example having an elongated roughly oval or rectangular shape as depicted in  FIG. 6 . In a practical implementation, each of the respective pieces of toe insulator  52  forming pad  54  and snap lock  66  may include molded non-metallic materials, including known polymeric materials or elastomeric materials suitable for injection molding. Pad  54  and snap lock  66  may each be formed throughout of non-metallic material. In other instances snap lock  66  and pad  54  might be machined, compression molded, or formed by any other suitable technique. 
     Pad  54  may further include a front face  90 , a back face  92 , and a transverse face  94  oriented diagonally relative to rail contact face  60  so as to form a V-profile, together with rail contact face  60 , from front face  90  to back face  92 . Each of front face  90  and back face  92  may extend from a first pad end  96  to a second pad end  98 . A first radiused edge or radius  97  may transition between front face  90  and rail contact face  60 . A second radiused edge or radius  99  may transition between rail contact face  60  and transverse face  94 . Each of radius  97  and radius  99  may extend from first pad end  96  to second pad end  98 . In one embodiment, a plane  100  as shown in  FIG. 8  bisects the V-profile, intersecting radius  99 , at a location mid-way between front face  90  and back face  92 . Plane  100  may be oriented normal to inner pad surface  56 , which may be planar. 
     Turning also now to  FIGS. 9 and 10 , snap lock  66  may further include a downwardly projecting prong, in the illustrated case two such prongs, including a first downwardly projecting prong  78  and a second downwardly projecting prong  80 , including second engagement surface  70 . Second engagement surface  70  may thus be formed in part upon each one of downwardly projecting prongs  78  and  80 . Downwardly projecting prongs  78  and  80  may be elastically deformable, each in opposition to an internal bias, in radially inward directions, to adjust snap lock  66  from a locked configuration to the unlocked configuration. Recesses  83  may be formed in outer peripheral surfaces  82 , and accessible to a user by way of clearance  88  when rail clip assembly  30  is assembled. A technician could insert a pry tool or the like into recesses  83 , and using the pry tool as a lever pop snap lock  66  out of engagement with locating projection  62 , elastically deforming downwardly projecting prongs  78  and  80  to disengage first engagement surface  64  from second engagement surface  70 , and thus decouple toe insulator  52  from rail clip  32 . Snap lock  66  may thus be understood to have a biased state where prongs  78  and  80  are deformed inwardly, and a rest state. Downwardly projecting prongs  78  and  80  may be elastically deformable in opposition to internal bias to adjust toe insulator  52  from the locked configuration, where second engagement surface  70  is in contact with first engagement surface  64 , for trapping locating projection  62  within insulator bore  50  in rail clip  32 , to an unlocked configuration where snap lock  66  is separable from pad  54  and locating projection  62  is removable from insulator bore  50 . 
     INDUSTRIAL APPLICABILITY 
     Referring to the drawings generally, but also now to  FIG. 11  and  FIG. 12 , when rail clip assembly  30  is installed for service the internal spring force produced by rail clip  32  can be exerted generally downward upon upper surfaces  9  of track rail  8 . Each of shoulders  22  may include an internal bore or recess  24  that receives the respective base end  34 . During installation, using an installation machine or manually by a technician, rail clip assembly  30  may be positioned adjacent to a shoulder  22 , and middle spring section  42  struck with an installation tool to simultaneously insert base end  34  into recess  24 , place middle spring section  42  in tension, and exert downward clamping pressure on upper surface  9 . During service, track rail  8  can experience loads causing track rail  8  to rotate or rock laterally, potentially lifting track rail  8  so as to form a clearance  110  between track rail  8  and rail pad assembly  14 . When the load subsides, spring force exerted by rail clip assembly  30  can assist in returning track rail  8  down to a stable seated position upon rail pad assembly  14 . The spring force can also reduce a tendency for track rail  8  to lift from substrate  12  at all. 
     In certain known rail clip assembly designs, insulators could be expected in such situations to rotate upward and around the corresponding rail clip end so as to deform, potentially plastically, and reduce the clamping load that might otherwise be applied. This phenomenon is believed to be due to various factors, but including insufficient rail contact surface area and limited mounting stability of the toe insulator itself. In the case of rail clip assembly  30 , rail contact face  60  has a contact length  112  that is relatively larger than certain known designs, for instance greater than 10 millimeters, and can assist in maintaining contact with upper surface  9  of track rail  8 , as well as providing a relatively longer plane contact length upon upper surface  9  to inhibit rocking of rail  8 . Moreover, the radiused surfaces formed by radius  97  and radius  99 , can assist in enabling pad  54  to controllably rock against the tilting upper rail surface  9 , and smoothly transition between loaded and tilted versus unloaded and stable states such as those depicted, respectively, in  FIG. 11  and  FIG. 12 . In addition, the positive locking of toe insulator  52  by way of the snap lock  66  and increased pad to rail contact length is contemplated to assist in resisting rotation of toe insulator  52  about toe and tip  40  as might be observed in certain other designs. 
     While in some systems a toe insulator is irreversibly attached, meaning removal without permanent deformation or other damage is impossible or impractical, in accordance with the present disclosure toe insulator  52  can be relatively easily removed in the field and either reinstalled or swapped for a new toe insulator. It should also be appreciated that while the use of a downwardly extending prong within an axially extending lock bore provides a practical implementation strategy for contact of engagement surfaces as discussed herein, the present disclosure is not thereby limited. In other instances, an upwardly extending prong might be formed on pad  54  and engaged within a bore formed in snap lock  66 . Analogously, rather than engagement surfaces internal to a projection or the like, another strategy might be used employing engagement surfaces formed externally. 
     The present description is for illustrative purposes only, and should not be construed to narrow the breadth of the present disclosure in any way. Thus, those skilled in the art will appreciate that various modifications might be made to the presently disclosed embodiments without departing from the full and fair scope and spirit of the present disclosure. Other aspects, features and advantages will be apparent upon an examination of the attached drawings and appended claims. As used herein, the articles “a” and “an” are intended to include one or more items, and may be used interchangeably with “one or more.” Where only one item is intended, the term “one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.