US3910492A

US3910492A - Insulated rail joints

Info

Publication number: US3910492A
Application number: US403623A
Authority: US
Inventors: Kenneth Stanley Sinfield
Original assignee: NATIONAL SPRINGS Pty Ltd
Current assignee: NATIONAL SPRINGS Pty Ltd
Priority date: 1972-10-10
Filing date: 1973-10-04
Publication date: 1975-10-07
Anticipated expiration: 1992-10-07
Also published as: GB1418967A; AU5993773A; DE2350152A1; CA1005413A; FR2202195A1; AT325086B; IT996260B; BE805899A; FR2202195B1

Abstract

A rail joint bar moulded as a solid component from a reinforced dielectric material, to finished cross-sectional shape and overall dimensions. The bar is shaped and dimensioned to include surfaces which tighten in a wedging action against the head and flange of a rail when bolted to the rail. A pair of the bars are secured on opposite sides of the rail web to form a rail joint, with the bars clear of the rail web by virtue of their engagement with the head and flanges of the rail, thus ensuring that the pair of bars move with the rail during service and retain their clamped position at all times.

Description

United States Patent Sinfield Oct. 7, 1975 [5 INSULATED RAIL JOINTS 3,335,954 8/1967 Hamilton, Jr. 238/159 [75] Inventor: Kenneth Stanley Sinfield, Strathfield 1/1969 eckert 8/243 I es Us Ta la Primary Examiner-M. Henson Wood, Jr.

[73] A gn National pri g Limited, Assistant ExaminerRichard A. Bertsch AleXandfla, Australia Attorney, Agent, or Firm-Waters, Schwartz & Nissen [22] Filed: Oct. 4, 1973 Appl. No.: 403,623

[ 57] ABSTRACT A rail joint bar moulded as a solid component from a reinforced dielectric material, to finished crosssectional shape and overall dimensions. The bar is shaped and dimensioned to include surfaces which tighten in a wedging action against the head and flange of a rail when bolted to the rail.

A pair of the bars are secured on opposite sides of the rail web to form a rail joint, with the bars clear of the rail web by virtue of their engagement with the head and flanges of the rail, thus ensuring that the pair of bars move with the rail during service and retain their clamped position at all times.

1 Claim, 7 Drawing Figures us. Patent 0. 7,19 5, sheetlofg 3,910,492

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US. Patent Oct. 7,1975 Sheet 2 of? 3,910,492

US. Patent (M11975 Sheet 3 of3 3,910,492

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FIG. 7

INSULATED RAIL JOINTS This invention relates to improvements in insulated rail joints and more particularly to insulated rail joint bars (fish plates) which are moulded a solid component from a reinforced dielectric material.

The invention also relates to a method of forming such rail joints using a pair of rail jointbars according to the invention secured to opposite sides of the webs of two rails, by bolts or similar clamping devices.

When forming insulated rail joints using steel fish plates, it has been general practice to interpose a layer of insulating material, whether as a separate piece or pieces or whether as an integral part of an assembly, between the fish plates and the rail which would otherwise engage each other, and also to insulate the bolts from the rail by a layer of insulating material, whether as a separate piece or pieces or whether as an integral part of an assembly, around the shanks of the bolts.

In this known technique, it has been found generally that the failure of such insulated rail joints occurs by a breakdown at the insulating surfaces either as a result of gradual wear or abrasion of such surfaces due to relative movement between the fish plates and the rail under the action of service loads or as a result of fatigue of the insulating layers under the action of stresses imposed by service loads. Also water absorption of the insulating layers has been found to materially increase the breakdown of these layers under service conditions.

In order to overcome electric failures of insulated rail joints whether using the known moulded dielectric bars or resulting from the failure of such insulating layers used in conjunction with steel fish plates, the present invention proposes the use of joint bars manufactured in such a way from a solid insulating or dielectric material so as to reduce the possible modes of failure to only that of a complete physical or mechanical rupture of the joint bars themselves.

According to the invention, the rail joint bar is moulded a solid component from a reinforced dielectric material to finished cross-sectional profile shape and overall dimensions and has a plurality of longitudinally spaced bolt holes formed therethrough. The bar is moulded from a thermosetting glass filament reinforced material having strands of the glass filament reinforcement running longitudinally of the bar and disposed in random spacing throughout the bar crosssection. The bar includes top and bottom surfaces adapted to respectively engage the under surface of a rail head and the upper surface of the rail flange when mounted upon the rail and is dimensioned to tighten in a wedging action against said rail surfaces when bolted to the rail.

Also according to the invention, a rail joint is formed by securing a pair of the rail joint bars to opposite sides ofa rail web, the pair of bars being bolted to the rail web with the top and bottom surfaces of the bar respectively engaging the under surface of the rail head and the upper surface of the rail flange, with the bar clear of the rail web.

The invention will now be described with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective of the rail joint bar, looking from one end of the bar and at the vertical outer surface thereof.

FIG. 2 is an elevational view of the bar looking at the vertical outer surface thereof.

FIG. 3 is a similar view to FIG. 2 but looking at the opposite (inner) surface of the bar.

FIGS. 4, 5 and 6 are sectional views taken on the planes 44, 55 and 6-6 of FIG. 2 and FIG. 7 is an end view of an assembly of a pair of the bars of the invention upon a rail.

In the illustrated embodiment, the bar is moulded to the finished profile shape and overall dimensions from a reinforced plastics material and has a plurality of longitudinally spaced bolt holes 2 formed therethrough either during the moulding operation or subsequently. No machine operations are required to produce the desired cross-sectional shape on the bar 1 and thus the continuity of the reinforcement is maintained in the areas between and surrounding the bolt holes 2. The cross-sectional shape of the bar is such that when mounted on a rail R as a pair, the bars engage the downwardly inwardly tapered under surface of the rail head H and the upwardly inwardly tapered upper surface of the rail flange F. Thus, when the pair of bars 1 are clamped to the rail by the clamping bolts B, they tighten in a wedging action between the surfaces referred to and they are clear of the rail web W. This ensures that the pair of bars 1 so clamped, tend to move with the rail R during service and retain their clamped positions at all times.

The cross-sectional profile of the bar 1 comprises a flat, vertical outer surface 3 blended by radiussed corners 4 into top and bottom surfaces. The top surface extends upwardly inwardly as at 5 from the upper radiussed comer 4 for a short distance and then downwardly inwardly as at 6 and the downwardly inwardly extending part 6 engages the under surface of the rail head. The bottom surface extends upwardly inwardly from the lower corner 4 as at 7 and engages the upper surface of the rail flange. The lower corner 4 is chamfered at 8 at the end regions of the bar 1.

The chamfers 8 provide clearance for the heads of dogspikes which are fixed in conventional manner for securing a rail to sleepers, a feature not found on other known joints of the type referred to with which conventional dogspikes and other known fasteners cannot be used.

The downwardly inwardly extending part 6 of the top surface and the bottom surface 7 are blended by suitable radiussed projections 9, into a pair of flat, vertical inner surfaces 10 which are set back from the projections 9 towards the outer surface 3, on each side of a centre region 11 of bar 1 which includes region 12 surrounding those bolt holes 2 (centre bolt holes), located in region 12, and the vertical, inner surface 11-12 extends to the full width of the bar 1.

A pair of steel plates 13 are bonded to the vertical outer surface 3 over the bolt holes 2 and they have bolt holes 14 formed therethrough registering with the bolt holes 2 in the bar 1. The steel plates are separated longitudinally from each other in the centre region 11 to maintain the insulating properties of a joint assembly of the bars 1 and they serve to distribute bolt clamping loads through the joint.

The bar 1 is moulded from a thermosetting polymer such as epoxide or unsaturated polyester resin, it is heavily reinforced with glass filaments. The filaments run longitudinally of the bar and they are disposed in random spacing throughout the bar cross-section. The use of a thermosetting resin of the type referred to, reinforced in the manner described, provides in the fi'ri ished bar, the necessary mechanical properties capable of withstanding the stresses induced by boltv tension through the joint bars when installed and stresses resulting from fluctuating bending loads applied by traffic to the rails to which the joints are secured, as well as those stresses induced by rail expansion and contraction due to temperature changes.

However, it is to be understood that the invention is not restricted to thermosetting resins of the type referred to. Developments in the plastics industry may produce other materials capable of providing'thcrequired properties in the joint, from which the joint can be 'moulded at a cost consistent with the cost of the joint as described.

I claim:

1. A rail joint bar moulded as a solid component from a reinforced dielectric material, said bar being moulded to finished cross-sectional profile shape and overall dimensions and having a plurality of longitudinally spaced bolt holes formed therethrough, said bar being moulded from a thermosetting, glass filament reinforced material having strands of the glass filament reinforcement running longitudinally of the bar and disposed in random spacing throughout the bar crosssection, said bar including top and bottom surfaces adapted to respectively engage the under surface of a rail head and the upper surface of the rail flange when mounted upon the rail and being dimensioned to tighten in a wedging action against said rail surfaces when bolted to the rail, the cross-sectional profile of the bar comprising a flat, vertical outer surface blended; by upper and lower radiussed corners into top and bot-. tom surfaces, 7 the top surface extending upwardly in-l wardly from the upper radiussed corner and then outer'surface and located on each side of a center inner vertical surface extending to the full width of the bar,

said center inner vertical surface being located in a center--region of the bar and including regions surlrounding those said bolt holes located in this region, a pair of steel plates bonded tothe vertical outer surface of the bar and separated longitudinally from each other in said center region of the bar, said steel plates having bolt holes formed therethrough in registerwith the bolt holes in the bar; the lowerradiussed corner of the bar 7 being chamfered at each end region of the bar beneath the respective steel plates.

Claims

1. A rail joint bar moulded as a solid component from a reinforced dielectric material, said bar being moulded to finished cross-sectional profile shape and overall dimensions and having a plurality of longitudinally spaced bolt holes formed therethrough, said bar being moulded from a thermosetting, glass filament reinforced material having strands of the glass filament reinforcement running longitudinally of the bar and disposed in random spacing throughout the bar cross-section, said bar including top and bottom surfaces adapted to respectively engage the under surface of a rail head and the upper surface of the rail flange when mounted upon the rail and being dimensioned to tighten in a wedging action against said rail surfaces when bolted to the rail, the cross-sectional profile of the bar comprising a flat, vertical outer surface blended by upper and lower radiussed corners into top and bottom surfaces, the top surface extending upwardly inwardly from the upper radiussed corner and then downwardly inwardly and the downwardly inwardly extending part engages the rail head under surface; the bottom surface extending upwardly inwardly from the lower radiussed corner and engaging the rail flange upper surface; the downwardly inwardly extending top surface part and the bottom surface part being blended by radiussed projections into a pair of flat vertical inner surfaces set back from the projections towards the outer surface and located on each side of a center inner vertical surface extending to the full width of the bar, said center inner vertical surface being located in a center region of the bar and including regions surrounding those said bolt holes located in this region, a pair of steel plates bonded to the vertical outer surface of the bar and separated longitudinally from each other in said center region of the bar, said steel plates having bolt holes formed therethrough in register with the bolt holes in the bar; the lower radiussed corner of the bar being chamfered at each end region of the bar beneath the respective steel plates.