WO1982000669A1

WO1982000669A1 - Rail fastening system

Info

Publication number: WO1982000669A1
Application number: PCT/AU1981/000118
Authority: WO
Inventors: Ltd R Mckay
Original assignee: Young H
Priority date: 1980-08-20
Filing date: 1981-08-18
Publication date: 1982-03-04
Also published as: GB2092211A; GB2092211B; NL8120304A; AU537442B2; DE3152271A1; MY8700208A; AU7456981A; CA1214760A

Abstract

A rail fastening system for use with wooden rail ties which includes a rail (4), a wooden tie (7), a rail plate (6) that lies between the rail (4) and tie (7). An attachment means (10) holds the support plate (6) in position and a pair of attachments (10) also hold the elastic rail fastener (15) in position relative to the rail (4). The base (16) of the fastener (15) seats in a recess (11) of shoulders (12) of two attachment pegs (10).

Description

RAIL FASTENING SYSTEM

This invention relates to a system of securing rails to wooden rail ties.

Conventionally rails have been secured in place to rail ties by placing a metal plate between the rail tie and the rail and securing the rail to the tie by driving dog spikes into the tie such that the dog spikes pass through the metal plate and a flange on the spike lies over the rail flange. Usually four spikes are used (two on either side of the rail) for each sleeper and the metal plate incorporates slots in predetermined positions for this purpose. The difficulty encountered with these conventional wooden rail ties are 1) due to wood shrinkage the dog spikes gain clearance above the rail flange lead ing to a loosening of the rail 2) due to the constant passing of trains the rails tend to distort resulting in a vertical hammering on the dog spikes and again tending to loosen them 3) in curved sections of the track the pressure of passing trains causes the metal plates to cut into the wooden tie on one side of the rail and this results in the metal plate becoming inclined and distorting the horizontal support for the rail 4) because of the constant traffic and the inadequate holding force of the dog spikes the wooden ties tend to move and drift apart or together and do not maintain a regular spacing once again resulting in inadequate rail support 5) once a plate loosens it hammers vertically on to and gradually cuts into the wooden tie.

Attempts to overcome these problems using elastic rail fasteners such as "Pandrol" have proved ineffective. With elastic fasteners the metal plate is modified to incorporate means for holding one portion of the fastener while a second portion lies on the rail flange. The metal plate is still secured to the tie by dog spikes but the rail is secured on to the metal plate by the elastic fasteners . These systems have proved ineffective because the problems one to four above still tend to occur mainly because the metal plate still becomes loose and the fastening of the metal plate to the wooden tie is still by dog spike and this affects the functioning of the elastic fastener.

German patent 1,253,297 and U.K. patent 2,022,657 each provide a fastening system comprising a rail plate positioned between a tie and a rail, an elastic rail clip and a clip holding means having spikes adapted to pass through holes in said rail plate to hold said rail plate in position and secure said clip holding means to said rail tie. These two specifications do provide a solution to the problems outlines above, However, the clip holding means in both these specifications requires expensive manufacturing techniques as each clip holder needs to be cast and then further treated.

It is an object of the present invention to provide a rail fastening system for wooden rail ties that minimizes manufacturing costs.

To this end the present invention provides a rail fastening system comprising a wooden rail tie, a rail, a rail plate positioned between said tie and said rail, a pair of attachment means located on opposite sides of said rail, adapted to secure said plate to said wooden tie, each said attachment means incorporating a recess above said plate and a spike extending into said tie and an elastic rail clamp associated with each pair of attachment means said clamp being of the kind in which one portion lies on the rail flange and the other portion is held within opposed recesses of said pair of attachment means.

By using pairs of attachment means rail clips of the kind shown in German patent 1,253,297 and U.K. patent 2,022,657 can be secured in position without using the rail clipholders of those two specification. By using attachment means which function to secure the plate and hold the elastic rail fastener the problems of prior art systems are avoided. Any vertical movement of the attachment means due to wood shrinkage or rail movement due to traffic load is accommodated within the working deflection range of the elastic fastener. Elastic fasteners are designed to provide an adequate hold down force over a range of deflection distances (that is the vertical distance between port ion of fastener on the rail and the portion held in the attachment means). However, in the prior art because the plate itself was effectively the holder for the fastener when it became loose because of loosening of the dog spikes from the wooden tie the effective hold down force between the tie and the rail was lost. In this invention the attachment means ensures that a direct link between the rail and the rail tie is maintained.

Ideally each attachment means includes a spike section for fastening to the wooden rail tie and a recess ed shoulder portion for accommodating portion of the fastener.

To further illustrate this invention a preferred embodiment will now be described with reference to the drawings in which figure 1 is a cross sectional view of a rail fastener of. this invention in position; figure 2 is a perspective view of a rail seat and figure 3 is a sectional view of an attachment means of this invention.

In figures 1 and 2 the rail flange 5 of the rail 4 lies on the support plate 6 which in turn is seated on the wooden rail tie 7. The attachment means 10 extends into the rail tie and secures the elastic fastener 15 in position.

The base 16 of the elastic fastener 15 seats within the recess 11 of shoulders 12 of the two attachment pegs 10 as shown in figure 2. The arms 17 of fastener 15 lie on rail flange 5. Each attachment peg 10 includes a serrated spike portion 13 which carries at its end an elastic barb 14. The serrations and the barb 14 retain the spike securely within the wooden tie 7. Left and right hand attachment pegs 10 are used with each rail fastener 15 and these pegs pass through preformed slots 9 in the support plate 6.

When correctly positioned the elastic fastener 15 can be deflected within the range of 8 to 17 mm and still maintain a satisfactory hold down force and without subjecting the fastener to undue stress. This deflection range means that any shrinkage of the wooden rail tie or vertical movement of the rail will be accommodated by the fastener. The support plate still functions to spread the load from the rail to the sleeper but plate movement no longer affects the attachment of the rail to the rail tie.

Since the elastic fasteners can be removed without affecting the positioning of the sleeper plate replacement of rails is a simple matter whereas In the prior art the dog spikes holding the rail , must be removed. Once removed the dog spikes of the plate must be repositioned on the tie. Such re-insertion of the dog spikes can only occur a few times before the tie suffers "spike kill". This problem is avoided in the present invention and rails can be replaced without affecting the position of the support plate on the tie.

Unlike the clip holders of U.K. specification 2,022,657 and German patent 1,253,297 the attachment pegs 10 are much cheaper to manufacture 1) because they require less material and enable a saving in metal to be made 2) if they are cast in moulds because of their smaller volume a larger number of pairs of legs can be made per moulding box than either of the clip holders of the prior art patents mentioned above 3) the pegs 10 of this invention need not be cast but can be forged from metal bar by forming and stamping which represents a significantly cheaper means of manufacturing because it avoids the energy and time consuming procedures of casting and moulding.

Thus the system of this invention overcomes the problems of the prior art in a simple way and still enables the support plates used with conventional dog spikes to be utilized.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A rail fastening system comprising a wooden rail tie, a rail, a rail plate positioned between said tie and said rail, a pair of attachment means located on opposite sides of said rail, adapted to secure said plate to said wooden tie, each said attachment means incorporating a recess above said plate and a spike extending into said tie and an elastic rail clamp associated with each pair of attachment means said clamp being of the kind In which one portion lies on the rail flange and the other portion is held within opposed recesses of said pair of attachment means .

2. A system as claimed in claim 1 in which said rail clamp incorporates two elastic arms which lie on the rail flange said arms being integral with a base portion the side edges of which are laterally disposed to said rail and interfit with complementary recesses in each one of said pair of attachment means.

3. A system as claimed in claim 1 in which said attachment means is formed by forging from metal bar.

4. Attachment means as defined in claim 2 or 3.