GB2261241A

GB2261241A - Railway rail fastening assembly

Info

Publication number: GB2261241A
Application number: GB9123590A
Authority: GB
Inventors: Stig Thim
Original assignee: ABETONG TEKNIK AB
Current assignee: ABETONG TEKNIK AB
Priority date: 1990-09-27
Filing date: 1991-11-06
Publication date: 1993-05-12
Anticipated expiration: 2011-11-06
Also published as: SE9003079L; GB2261241B; SE9003079D0; GB9123590D0

Abstract

A railway rail fastening assembly includes two rail fastening blocks (1) provided with recesses for the accommodation of spring elements (not shown) which engage the base flange (not shown) of a rail. Provided between the rail and the sleeper block is an insulating pad (2) made of elastic or elastomerio material. Provided in each of two edge parts (1f) of respective rail fastening blocks (1) is a notch-shaped recess (1g) which coacts with a corresponding projection on respective pads such as to urge the pads downwards against the sleeper block and therewith anchor the pads thereto. <IMAGE>

Description

A Rail Fastening Block and a Coactina Insulating Pad The present invention relates to a PANDROL-type rail fastening assembly, and more specifically to the type of rail fastening assembly defined in the preamble of Claim 1.

SE,B, 7306727-4 (A-Betong) describes and illustrates a rail fastening assembly of this kind in which the insulating pad is embodied in the sleeper.

EP-Al-O 313 327 (Pandrol) describes and illustrates a rail fastening assembly of the kind with which the present invention is concerned. This assembly includes an insulating pad having upstanding side portions which are formed with recesses for accommodating a respective spring device which engages the base flange of a railway rail and which secure the insulating pad in position.

GB-A2-114,635 (Hartfield Rubber) describes and illustrates a similar rail fastening assembly comprising rubber insulating pads having two upstanding, mutually parallel walls which embrace the base flange of a railway rail. The walls are reinforced by metal bars provided with rubber-embedded projections to provide the pad with reinforced locating ears which embrace the anchorage blocks.

The latter two assemblies - which are intended to enable the insulating pad to be secured and held accurately in position, even when subjected to vibrations and stresses, are unnecessarily complicated and therewith expensive.

Such insulating pads are therefore normally of simpler construction and are firmly bonded to the sleeper block by means of an appropriate adhesive. This adhesive bonding of the pad to the sleeper block is a relatively complicated procedure and there is a risk that the adhesive bond will disintegrate with time, resulting in loosening of the pad.

Accordingly, the object of the present invention is to provide a railway rail fastening block and an associated insulating pad of comparatively simple construction which will enable the pad to be reliably anchored to an associated rail fastening block irrespective of whether or not an additional join, such as an adhesive join for example, is used between the pad and the sleeper block.

This and other objects are fulfilled by an inventive rail fastening assembly of the aforementioned kind which has the essential characteristic features set forth in the characterizing clause of the following Claim 1.

The invention ensures that the insulating pad, which is made of an elastic material, such as a rubber, or of an elastomeric material, such as an elastomeric plastic material, is pressed down against the sleeper block, thereby reliably fixating the pad. In practice, this fixation of the pad will be sufficiently effective, even should the sleeper as a whole be subjected to wind stresses, vibrations and other types of stresses when transporting sleepers to the construction site.

A rail fastening block which can be used effectively when practicing the invention will present a cornered or edged cross-section, for example a rectilinear crosssection of varying side length, including a square. It is preferred, in this case, that the recess will be provided at one edge or at one corner of a respective block.

In turn, the pad is preferably provided in the region of respective securing blocks with a recess which is adapted to a part of the cornered or edged outer profile of the block. In this case, it is preferred that the plate presents adjacent each securing block two projections which are each received in a corresponding respective recess at one corner or at one edge of respective blocks.

The symmetrical anchorage arrangement achieved in this way enhances the reliability of the anchorage.

This reliability is further enhanced when, in accordance with one preferred embodiment of the invention, the recess or recesses is/are defined by an upper, substantially horizontal surface which merges with a downwardly extending surface of concave curvature.

When the pad projections coacting with the respective block recesses are correspondingly configured, the intrinsic elasticity of the pad material will contribute effectively towards the reliability of the anchorage.

The invention will now be described in more detail with reference to an exemplifying embodiment of the invention and with reference to the accompanying drawings JL;cG, Figure 1 is a perspective view of a railway rail fastening block forming part of an inventive rail fastening assembly.

Figure 2 is a view from above of two mutually coacting rail fastening blocks which are intended to be mounted on one sleeper block on either side of a rail, and also shows an insulating pad which is anchored in accordance with the invention and which is made of rubber or some other elastic material.

Figure 3 is a sectional view taken on the line III-III in Figure 2 and shows the configuration of the block recess and the configuration of a corresponding pad projection.

Figure 4 is a perspective view of part of a sleeper block provided with two mutually coacting fastening blocks having spring elements which function to anchor a rail against an insulating pad fitted to the sleeper block.

A railway rail fastening assembly comprises two rail fastening blocks 1 which are anchored to a sleeper block 3 on a respective side of a railway rail 4. Each such rail fastening block comprises a main part la, which is positioned over the sleeper block, and an anchoring part lb which projects into a hole in the sleeper block and which has mutually parallel anchoring flanges lc, id.

The main part la of the fastening block is provided with a penetrating recess le which is intended to accommodate a spring element 5 bent, for instance, to an approximate G-shape or e-shape. The spring element 5 is intended to grip against the base flange 4a of the rail and therewith anchor the rail in position.

The main part la of the illustrated rail fastening block 1 has a rectangular cross-section, which includes a square cross-section, having four corners or edges lf.

Located between the rail and the sleeper block is an electrically insulating pad 2 which is made of an elastic material, such as rubber, or an elastomeric material, such as a plastic material, and which is secured in a respective rail fastening block.

The pad 2 is provided in the region of respective rail fastening blocks with a recess which is adapted to that part of the outer profile of the cornered or edged block which is level with the pad. In other words, the pad profile conforms to a part of the outer profile of respective rail fastening pads, so that the pad partially embraces the outer profile of the block.

Provided in those corners or edges lf of respective rail fastening blocks which face towards the elastic pad 2 is a notch-like recess ig which lies level with the pad and which is intended to receive a corresponding projection 2a, such as to anchor the pad to the sleeper block. The recesses lg and the corresponding projections 2a are so configured as to press the insulating pad 2 downwards and fixate the pad on the sleeper block.

In the case of the illustrated embodiment, the recesses lg are defined by an upper, substantially horizontal surface which merges with a downwardly extending surface of concave curvature. As will be seen from Figure 3, when a projection is inserted into a recess, the side edge of the projection 2a of the pad 2 will be caused to extend horizontally while the bottom surface of the projection will adapt to the concave curvature of the recess. The intrinsic elasticity of the pad material will therewith assist in urging the pad downwards, so as to achieve reliable anchorage of the pad against the underlying sleeper block.

The symmetrical arrangement of the two recesses lg of respective rail fastening blocks and the fact that the pad - as above described - conforms to the outer profile of the fastening block also contribute to reliable anchorage of the pad.

Claims

1. A railway rail fastening assembly comprising two rail fastening blocks which are anchored on a respective side of a rail and each of which is provided with a recess for accommodating a bent spring element which is intended to engage the base flange of the rail such as to anchor the same, and which assembly further comprises an electrically insulating pad made of an elastic or an elastomeric material, such as rubber or plastics material, positioned between the rail and the sleeper block, characterized in that the rail fastening blocks are each provided with a further recess for coaction with a corresponding projection on the insulating pad; and in that the further recess is configured in a manner to press the insulating pad downwards such as to fix the pad on the sleeper block.

2. A rail fastening assembly according to Claim 1, wherein the spring element is bent in an approximate Gor E-shape.

3. A rail fastening assembly according to Claim 1 or Claim 2, wherein the rail fastening blocks have on a level with respective recesses a cornered or edged section, wherein the further recess is provided at one edge or at one corner of respective rail fastening blocks.

4. A rail fastening assembly as claimed in Claim 3, wherein the cornered or edged section is of rectangular or square cross-section.

5. A rail fastening assembly according to Claim 3 or Claim 4, in which the pad presents in the region of respective rail fastening blocks, a recess which is adapted to a part of the cornered or edged outer profile of the fastening blocks, wherein the pad presents at each fastening block two projections which are each accommodated in a respective corresponding further recess provided in one corner or at one edge of respective rail fastening blocks.

6. A rail fastening assembly according to any one of Claims 1-5, wherein the further recess or further recesses is/are defined by an upper, substantially horizontal surface which merges with a downwardly extending surface of concave curvature.

7. A rail fastening assembly substantially as hereinbefore described with reference to, and as illustrated by, the accompanying drawings.