The present invention related to a rail-mounting assembly of the type in which a metal top plate is received in a base frame that is attached to a sleeper or rail bed and a cushion of elastomer bonded to both the top plate and the base frame is provided between the juxtaposed faces of the two parts.
Successful rail mounting assemblies are disclosed in U.S. Pat. No. 6,789,740 and to U.S. patent application Ser. No. 10/691,454. In these rail mounting assemblies which can be referred to as “egg” designs, the frame has a generally elongated or oval opening formed at its ends with inclined faces and four lugs symmetrically disposed at opposite ends of the frame to receive bolts for attachment of the base plate to the support structure.
The top plate is also symmetrical about the longitudinal axis and has at its ends inclined faces juxtaposed with the inclined faces of the frame and bonded, e.g. by vulcanization, to an elastomer body received between the juxtaposed faces and extending around the sides of the top plate and the frame. Such track fasteners are particularly useful for vibration-sensitive locations.
The principal object of the present invention is to provide an improved system-wide track fastener or rail-mounting assembly that has some of the advantages of the designs described in the two cited publications and to make the rail-mounting assembly more universally applicable and acceptable.
Another object is to provide a track fastener that is an improvement over traditional two-bolt fasteners currently available for systemwide application.
These objects and others that will become apparent hereinafter are attained, in accordance with the invention with an asymmetrical structure in which the base plate is formed at two diagonally opposite corners with beveled or truncated regions having elongated holes for receiving the bolts, the other corners of the otherwise rectangular or substantially rectangular base plate being formed with right angles. According to the invention, instead of having the inclined end faces on abutments extending arcuately substantially all across the opening in the frame, as in U.S. Pat. No. 6,789,740 and patent application Ser. No. 10/691,454, the asymmetrical rail-mounting assembly of the invention has a pair of mutually parallel and linearly extending abutments that form the inclined faces and are disposed adjacent the beveled sections, respectively.
Similarly, the top plate is asymmetrical in the sense that the eyes or bosses formed thereon to straddle the rail that rests upon the rectangular plate portion between these bosses, are diagonally opposite one another instead of being located along the axis of symmetry as in U.S. Pat. No. 6,789,740 and patent application Ser. No. 10/691,454. These bosses are contiguous with formations provided with the inclined faces juxtaposed with the end faces of the base plate and are bonded to an elastomeric layer that fills the space between the juxtaposed faces and between the sides of the top plate and the sides of the frame. We have found that the preferred angle between the vertical and these faces should be 42°±25° and more preferably 42°±10°. Best results are obtained when the angle is 42°±5° with the very best results at 42°±2°. The 42° angle is optimum to maximize lateral v. vertical stiffness. Other angles can lower the ratio of lateral to vertical stiffness.
The elastomeric material of the body can be molded over the aforementioned abutments so as to extended between the juxtaposed faces and then over and around the sides and back of each abutment.
According to a feature of the invention, the elastomeric body also extends from the gap between the parallel sides of the top plate and frame over the frame sides and onto the outer faces of the frame sides. The top of the frame sides and the top of the abutments over which the elastomeric body is formed can be rounded.
According to another feature of the invention, the elastomeric body forms a number of pads on the underside of the top plate and between the top plate and any supporting face on which the rail-mounting assembly is anchored. These pads, for example, can include two triangular pads in the regions of the beveled areas receiving the bolts and two rectangular pads each underlying a respective boss and the raised formation provided with the inclined face of the top plate.
The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which:
The essential elements of the rail-mounting assembly shown in the drawing are a cast-metal base frame 10, a cast-metal top plate 11 and a one-piece body 12 of elastomeric material bonded to juxtaposed on confronting faces of the top plate 11 and the base frame 10. As can be seen from
As can be seen best from FIGS. 11 to 16, the top plate 11 can also have a Z-shaped outline complimentarily fitting in the opening or window 14 and has a mainly planar lower face 28 having at its ends crosswise and downwardly projecting ridges 29. The top plate 11 has downwardly and inwardly inclined faces 30 and 31 that can confront and extend par to the faces 26 and 25 when the parts 10 and 11 are slightly spaced. These faces are also inclined at 42°±25° but or course have the same angle as the faces 25 and 26. Inwardly of these faces 30 and 31, the top plate 11 is provided with two semicylindrical bosses or lugs 33 and 34 that can be tubular to accommodate track hold-down fasteners engageable with the respective outer flanges of a track rail shown particularly in
As is also apparent from FIGS. 11 to 16, the top plate 11 has side edges 36 and 37 that can be juxtaposed with the ribs 15 and 16 when the top plate 11 is inserted in the frame 10. When the top plate 11 is inserted into the frame 10, the body 12 of elastomeric material is molded between the frame 10 and the top plate 11 in one piece so that the elastomer, for example, is bonded at 39 between the juxtaposed faces 26 and 30 and in addition is bonded between the side walls of the frame and the sides of the top plate 11 as shown at 40 and 41 (
As can be seen from
Unlike the system of the aforementioned patent, with the 42° angle of the load-transferring faces, the load is transferred in both shear and compression. The system requires only two anchor bolts, thereby simplifying the use of the device. The inclined faces increase lateral stiffness in a way that has not been obtainable with earlier two bolt designs.
The side walls of the top plate can be completely surrounded with the elastomer, thereby buffering all forces transmitted by the top plate. The elastomer prevents extreme forces from reaching the frame and hence the anchor bolts, thereby eliminating anchor bolt failure and deterioration of the female inserts into which the anchor bolts are engaged. The frame acts as a containment completely surrounding the periphery of the top plate thereby providing positive lateral and longitudinal restraint i.e. a fail-safe restraining that is effective even in the event of failure of the elastomer or its bond to the metal.
The lowest point of containment of the face 35 is above the elastomer connecting the top plate 11 to the frame 10, thereby protecting the elastomer against wear. A change in the elastomer durometer or number of pads, of pad sizes, pad locations, pad configurations, pad depth or any combination of these on the underside of the top plate allows vertical stiffness to be altered. The invention permits additional pads to come into play as deflection increases, thereby making possible a track fastener with dual or even triple vertical spring stiffness. While the angles of inclination of the faces 26, 30 and 25, 31 can be the same and most preferably 42° as noted, if special stiffness characteristics are desired, the angles of both end inclined faces can be varied for example through a range of 15° to 75° unequally so that the angle at one end could be say 45° and the angle at the other end 30°.
The side walls and lower face of the top plate can be covered totally or partially by the elastomer to buffer all forces transmitted from the top plate and thereby buffering or reducing the forces that are transmitted to the anchor bolts, thereby reducing bolt failure and the failure of anchor inserts in the concrete. The frame, as in the egg design, completely surrounds the periphery of the top plate providing positive lateral and longitudinal restraint.
This application is related to provisional application 60/656,217 filed 25 Feb. 2005.
Number | Date | Country | |
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60656217 | Feb 2005 | US |