US3784097A

US3784097A - Direct fixation rail fastener

Info

Publication number: US3784097A
Application number: US00297318A
Authority: US
Inventors: R Landis
Original assignee: Landis Sales Co
Current assignee: LANDIS INDUSTRIES Inc; Landis Sales Co
Priority date: 1972-10-13
Filing date: 1972-10-13
Publication date: 1974-01-08
Anticipated expiration: 1991-01-08
Also published as: AU6074973A; BR7307973D0; GB1435116A; FR2202979A1; DE2350815A1; JPS4972811A; FR2202979B3

Abstract

The track of a rapid transit rail system is fastened to a supporting structure via the intermediary of a plurality of rail fasteners. Each rail fastener includes a track plate supported from a base plate via the intermediary of an elastomer layer bonded between the plates. A pattern of voids is provided in the elastomer to enhance the vibration damping effect of the elastomer layer. Increased lateral restraint for the track plate and rail is provided by means of a pair of tubular members upstanding from the base plate on opposite sides of the rail. High compressive strength inserts are provided between the lateral side edges of the track plate and the upstanding tubular members for taking the lateral forces on the track plate in compression on the insert members.

Description

United States Patent [191 Landis Jan. 8, 1974 [73] Assignee: The Landis Sales Company, Los

Altos, Calif.

[22] Filed: Oct. 13, 1972 [21] Appl. No.: 297,318

Primary Examiner-Gerald M. Forlenza Assistant Examiner-Richard A. Bertsch Attorney-Harvey G. Lowhurst et a1.

[57] ABSTRACT The track of a rapid transit rail system is fastened to a supporting structure via the intermediary of a plurality of rail fasteners. Each rail fastener includes a track plate supported from a base plate via the intermediary of an elastomer layer bonded between the plates. A pattern of voids is provided in the elastomer to enhance the vibration damping effect of the elastomer layer. Increased lateral restraint for the track plate and rail is provided by means of a pair of tubular members upstanding from the base plate on opposite sides of the rail. High compressive strength inserts are provided between the lateral side edges of the track plate and the upstanding tubular members for taking the lateral forces on the track plate in compression on the insert members.

[52] U.S. Cl 238/310, 238/282, 238/283, 238/304 [51] Int. Cl. Blb 9/62 [58] Field of Search 238/287, 304, 282, 238/264, 283, 308, 374, 297

[ 5 6] References Cited UNlTED STATES PATENTS 2,719,676 10/1955 Prater 238/283 3,387,781 6/1968 Moses et al 238/283 3,451,621 6/1969 De Splinter 238/283 3,576,293 4/1971 Landis 238/310 3,581,990 6/1971 Kirik 238/287 Q o e a d PATENTEU 8 SHEET 1 0F 2 IINU DIRECT FIXATION RAIL FASTENER DESCRIPTION OF THE PRIOR ART Heretofore, rapid transit rail systems have been fastened to underlying support structures, as of concrete, via the intermediary of a plurality of rail fasteners. These rail fasteners have included a track plate affixed to the rail and a base plate affixed to the supporting structure with an elastomer layer bonded in between the track plate and the base plate for damping vibration of the track and for electrically insulating the track from the base structure. Lateral restraint for the rail has been provided by means of an upturned side lip of the base plate which restrained the lateral deflection of the track plate and, therefore, the rail via compression of a thickness of the elastomer bonded in place between the lateral spaced longitudinal directed side edges of the track plate and the upstanding lip portion of the base plate. Such a rail fastener is disclosed and claimed in U. S. Pat. No. 3,576,293 issued Apr. 27, 1971 and assigned to the same assignee as the present invention.

One of the problems encountered in this prior rail fastener is that when the elastomer layer is provided with voids for increasing the vibration damping effect of the rail fastener, some of the lateral restraint provided by the bonded layer of elastomer material is removed, thereby placing higher compressive loads on that portion of the elastomer layer interposed between the upturned lip of the base plate and the lateral spaced side edges of the track plate. As a result, the compressive forces on that portion of the elastomer intervening between the lip and the lateral side edges of the track plate was excessive producing excessive lateral deflection of the track plate and rail affixed thereto.

It is also known from the prior art that voids may be provided in the elastomer layer between the track plate and the base plate for increasing the vibrational damping effect of the rail fastener. Such a prior rail fastener including a system of voids for vibration damping is disclosed in U. S. Pat. No. 2,656,l 16 issued Oct. 20, 1953.

SUMMARY OF THE PRESENT INVENTION The principal object of the present invention is the provision of an improved direct fixation rail fastener for fastening a track to a support structure and for providing vibrational damping and electrical isolation between the track and the supporting structure.

In one feature of the present invention, a lateral restraining structure is disposed upstanding from the base plate on opposite lateral sides of the track and a high compressive strength insert is interposed between the adjacent edge of the track plate and the upstanding lateral restraining structure for taking in compression and transferring lateral forces on the track plate to the upstanding lateral restraining means, whereby increased lateral restraint is obtained for the rail to prevent excessive lateral deflection thereof in use.

In another feature of the present invention, the lateral restraining structure includes a pair of tubular members upstanding from the base plate on opposite sides of the track and means are provided for rigidly coupling the upstanding tubular members to the base plate such that the tubular members may withstand substantial lateral force without excessive deflection.

In another feature of the present invention, the tubular lateral restraining members, upstanding from the base plate, are of rectangular or square cross-section and the track plate includes a pair of square or rectangular apertures coaxially aligned with the tubes. High compressive strength inserts having a pair of rectillinear portions are interposed between the mutually opposed laterally spaced flat side edges of the tubes and the rectillinear side edges of the apertures in the track plate, whereby the high compressive strength inserts can be uniformly loaded for transferring the lateral restraining forces between the track plate and the laterally restraining tubular members.

In another feature of the present invention, the elastomer layer is provided with a plurality of elongated voids laterally directed of the track and spaced apart along the direction of the track with the base plate being apertured in registration with each of said elongated voids.

Other features and advantages of the present invention will become apparent upon a perusal of the following specification taken in connection with the accompanying drawings wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a rail and rail fastener assembly incorporating features of the present invention,

FIG. 2 is an enlarged plan view of the structure of FIG. 1,

FIG. 3 is a sectional view of the structure of FIG. 2 taken along line 3-3 in the direction of the arrows,

FIG. 4 is a sectional view of the structure of FIG. 2 taken along line 4-4 in the direction of the arrows,

FIG. 5 is a sectional view of the rail fastener portion of the structure of FIG. 2 taken along line 5-5 in the direction of the arrows, and

FIG. 6 is an enlarged perspective view of a portion of the structure of FIG. 3 delineated by line 66.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to F IG. 1, there is shown a rail fastener 1 of a type incorporating features of the present invention for fastening a rail 2 to a supporting structure 3, such as a concrete slab. The rail fastener l is an improvement of the rail fastener disclosed and claimed in the aforecited US. Pat. No. 3,576,293 and the disclosure in this patent is hereby incorporated by reference for a detailed description of the type of rail fastener of which the present invention is an improvement.

Referring now to FIGS. 2 and 3, the rail fastener 1 will be described in greater detail. The rail fastener 1 includes a base plate structure 4, as of M1 inch mild steel plate, disposed overlaying the concrete slab 3 to which it is secured by means of a pair of bolts 5 disposed at opposite diagonal corners of the base plate 4. The bolts pass through apertures 6 in the base plate 4 to threadably mate with a metallic insert 7 anchored in the concrete slab 3. In a typical example, the base plate 4 has a lateral width of approximately 14.5 inches and a longitudinal extent, parallel to the direction of the rail, of approximately 7.5 inches.

A track plate 8, as of -inch mild steel, is disposed overlaying the base plate 4. An elastomer layer 9 is vulcanized (bonded) in place between the base plate 4 and the track plate 8 to provide vibrational damping for the track plate and to electrically isolate the track plate 8 from the base plate 4. In a typical example, the elastomer layer 9 has a thickness of 0.75 inches. A shimming polyethylene gasket or pad 11 is interposed between the base plate 4 and the concrete slab 3 to to accommodate vertical alignment of the rail 2.

A pair of rail clips 13 serve to clip the skirt portions of the bottom flange of the rail 2 to the track plate 8. The rail clips 13 are disposed in diagonally offset relation on opposite sides of the rail 2. The rail clips 13 are bolted to the track plate means of two %-111Ch bolts 14 passing through bores 15 in the clips 13 and tightened down by nuts 16 onto lock washers 17.

The rail 2 is laterally adjustable by lateral adjustment of the positions of the rail clips 13. For this purpose, two laterally directed T slots 18 are provided in the track plate 8 and in the underlying region of the elastomer layer 9. The head portions 19 of the bolts 14 ride in that portion of the slots 18 which extend into the elastomer layer 9 such that the head of the bolt is caught on the lower lip of the T-slot in the track plate 8. An upper portion of the track plate which is adjacent the T slot is provided with longitudinally directed serations at 21 to receive a gripping land portion 22 on the underside of the rail clip 13 to prevent slipping of the rail clip relative to the track plate when the nuts 16 have been tightened. That portion of the T-slot 18 which extends into the elastomer layer 9 is opened to the adjacent front or rear'edge of the rail fastener 1 for irrigation of the T-slot to prevent accumulations of corrosive substances therein.

A plurality of laterally directed elongated voids 25 are provided in the elastomer layer 9 (see FIGS. 2 and 5) in the central region generally underlaying the rail 2. The voids serve to increase the compliance of the elastomer layer 9 for increasing the vibration damping effect of the elastomer layer 9. In a typical example, the voids 25 are approximately three-eights of an inch wide and 4 to 6 inches in length depending upon the position of the slots. The slots extend through the base plate 4 and to within aproximately one-sixteenth of an inch of the bottom surface of the track plate 8. The slots 25 are spaced apart along the direction of the rail 2 by approximately 1 inch between center lines.

Some lateral restraint of the track plate 8 is obtained due to the shear forces generated by the bond between the elastomer layer 9 and the base plate 4 and track plate 8, respectively. However, due to the provision of the voids 25 substantial additional lateral restraint is desirable to prevent undue lateral deflection of the rail 2.

Accordingly, (See FIGS. 2-4) a pair of generally square apertures 27, provided in diagonal corners of the track plate 8,- coaxially surround the holddown bolts 5. The square apertures 27 are oriented with rectilinear sides parallel to the longitudinal axis of the rail 2. Square tubular spacers 28 are disposed coaxially of the bolts 5 with the flat sides of the square tubular spacers 28 being parallel to the rectilinear sides of the openings 27 in the track plate 8.

A high compressive strength electrically insulative insert 29, as of nylon, is coaxially interposed between the side walls of the apertures 27 and the tubular spacer 28. The coaxial arrangement of the insert 29 and tubular spacer 28 is shown in perspective view in FIG. 6. The insert 29 includes a pair of longitudinally directed laterally spaced generally bar-shaped portions 31 interconnected by a pair of laterally directed relatively thin web portions 32. The longitudinally directed bar portions 31 serve to take laterally directed forces exerted on the insert 29 in compression and to transmit those forces to the tubular spacer 28 which serves as the lateral restraining member. In a typical example, the tubular spacer 28 has an axial length of l and 19/32 inches and is of square cross-section having a 3/ 1 6th inch wall thickness and being 1.5 inches on a side, and being made of mild steel. in a typical example, the insert 29 has a square inside aperture l.5 inches on a side with the depth of the insert being three-fourths of an inch and the lateral extent of each bar portion 31 being onehalf inch. The retaining webs 32 are only a few thousandth of an inch thick.

A mild steel washer 35, as of 2.25 inch diameter with an inside hole size of l5/l6ths inch diameter and having a thickness of 0. l 65 inches, is captured between the upper end of the tubular spacer 28 and the head of the holddown bolt 5. The tubular spacer 28, insert 29, and washer 35 are all vulcanized in position and embedded in the elastomer material there being a raised pad portion 36 of the elastomer material extending approximately one-half inch above the track plate 8 at the holddown corners of the track plate 8. The raised vulcanized pad portions 36 prevent corrosive contaminants from leaking into the holddown bolt holes. In addition, the raised pad portion 36 of the elastomer material further facilitates electrical isolation of the base plate from the track plate, as conductive fluids might otherwise tend to make an electrical connection between the track plate and the base plate 4 through the intermediary of the tubular spacers 28.

When the holddown bolts 5 are tightened down onto the washers 35, the tubular spacers 28 are placed in compression so as to form a rigid lateral restraining structure upstanding from the base plate 4. When the lateral forces on the track plate 8 are in one direction, such as F (FIG. 6) one bar portion 31 of the high compression strength insert 29 takes the lateral forces in compression. More particularly, the inside bar portion 31 of one of the restraining inserts takes one-half of the lateral force on compression and the other half of the lateral force is taken in compression on the outside bar portion 31 of the other restraining insert 29. Conversely, when the lateral forces are in the opposite direction, such as F the outside bar portion 31 of one of the restraining inserts takes one half of the lateral restraining force and the inside bar portion 31 of the other restraining insert 29 takes the other half of the lateral force. In a typical example, the inserts 29 take 5,000 pounds of the lateral load in compression without producing undue lateral deflection of the rail 2.

What is claimed is:

1. In a rail fastener for fastening a track to a support structure and for providing vibrational damping and electrical isolation between the track and the support structure:

base plate means for attachment to the underlying support structure;

track plate means for attachment to a track, said track plate means being disposed overlaying said base plate means;

elastomer means interposed between said base plate means and said track plate means fo supporting said track plate means from said base plate means and for damping vibration of said track plate means and for electrically insulating said base plate means from said track plate means;

means for securing the track to said track plate means such that the track will overlie the track plate in a predetermined track region of said track plate means;

means for restraining lateral displacement of said track plate means relative to said base plate means, said lateral restraining means including, means upstanding from said base plate means on opposite lateral side of said track region of said track plate means for restraining excessive lateral displacement of said track plate means, insert means interposed between an adjacent edge of said track plate means and said upstanding lateral restraining means for taking in compression and transferring lateral forces on said track plate to said upstanding lateral restraining means, said insert means having a substantially higher compressive strength than that of said elastomer means and being made of an electrically insulative material for electrically insulating said lateral restraining means from said track plate means.

2. The apparatus of claim 1 wherein said upstanding lateral restraining means includes, a pair of tubular members upstanding from said base plate means on opposite lateral sides of said track region of said track plate means.

3. The apparatus of claim 2 wherein each of said tubular members is coaxially aligned with respective apertures in said base plate means.

4. The apparatus of claim 3, including, threaded fastener means for securing said base plate means to the underlaying support structure, said fastener means passing coaxially through said tubular members and aligned apertures in said base plate means to take said tubular members in compression against said underlying base plate means.

5. The apparatus of claim 4 wherein each of said tubular members includes at least one generally flat side facing a generally flat edge portion of said track plate means, and wherein each of said respective means includes a pair of flat sides one facing the adjacent flat side of said tubular member and the other facing the adjacent flat edge portion of said track plate means.

6. The apparatus of claim 5 wherein said track plate means is apertured with a pair of rectangular openings coaxially aligned with said tubular members.

7. The apparatus of claim 1 wherein said elastomer means includes a plurality of voids therein for increasing the vibration damping of said elastomer means.

8. The apparatus of claim 7 wherein said voids are elongated laterally of a track, and are spaced apart along the direction of the track.

9. The apparatus of claim 7 wherein said base plate means is apertured in registration with each of said voids.

Claims

1. In a rail fastener for fastening a track to a support structure and for providing vibrational damping and electrical isolation between the track and the support structure: base plate means for attachment to the underlying support structure; track plate means for attachment to a track, said track plate means being disposed overlaying said base plate means; elastomer means interposed between said base plate means and said track plate means fo supporting said track plate means from said base plate means and for damping vibration of said track plate means and for electrically insulating said base plate means from said track plate means; means for securing the track to said track plate means such that the track will overlie the track plate in a predetermined track region of said track plate means; means for restraining lateral displacement of said track plate means relative to said base plate means, said lateral restraining means including, means upstanding from said base plate means on opposite lateral side of said track region of said track plate means for restraining excessive lateral displacement of said track plate means, insert means interposed between an adjacent edge of said track plate means and said upstanding lateral restraining means for taking in compression and transferring lateral forces on said track plate to said upstanding lateral restraining means, said insert means having a substanTially higher compressive strength than that of said elastomer means and being made of an electrically insulative material for electrically insulating said lateral restraining means from said track plate means.