GB2147350A

GB2147350A - Rail clamp for railway equipment

Info

Publication number: GB2147350A
Application number: GB08409832A
Authority: GB
Inventors: Luis Fernando Villar
Original assignee: Servo Corp of America
Current assignee: Servo Corp of America
Priority date: 1983-10-03
Filing date: 1984-04-16
Publication date: 1985-05-09
Also published as: SE8404604L; DE3432687A1; SE8404604D0; FR2552917A1; BR8401997A; AU2548484A; JPS6095002A

Abstract

A clamp (10) for connecting equipment (40) to a rail (50) of a railway track comprises a housing (12) having a platform (14) on which a pair of shock isolators (16, 18) are fixed for mounting the equipment (40). A threaded rod (52) extends from the housing (12) and carries an adjustable claw (54) which co-operates with a fixed claw (42) on the housing to grip the bottom flange of the rail (50) between them and thereby secure the clamp to the rail. An eccentric cant adjustment nut (66) is mounted on the rod (52) between the claws (42 and 54). The isolators (16, 18) include shock absorbing material and electrical insulation material for the purpose of insulating the equipment (40) from the rail (50) and protecting it from mechanical shocks and vibrations. <IMAGE>

Description

SPECIFICATION Rail clamp for railway equipment The present invention relates to the track mounting of railway equipment, and is particularly concerned with a clamp for connecting the equipment to a rail of the track.

In U.S. Patent No. 3545005 there is disclosed a hot box detector which is designed to be rail mounted instead of being ballast mounted on the ground beside the track. Rail mounting the detector scanner eliminates the need for foundations, which is a considerable installation cost when ballast mounting, and also the on-going maintenance involved with the monthly alignment of ballast mounted scanners. The periodic alignment of ballast mounted scanners is necessary to pinpoint accurately the scanner optical spot location, which tends to shift as a result of movement of the foundation upon which the scanner is mounted as well as "rail creep" and "rail run" produced by the passage of trains over the track in the vicinity of the scanner.In addition, rail mounting the scanner permits identical scanning of all bearings of a given type by retaining a fixed relationship between the scanner, wheel presence transducer, and the bearing housing, since the scanner is fixed to and moves with the rail.

However, while the rail mounting of hot box detectors has certain clear advantages over ballast mounting, there are two disadvantages, firstly the need to protect the sensitive electrical components of the scanner by effectively insulating them from the rail, and secondly the mechanical components of the scanner are more subject to fatigue as a result of their movement with the rail.

With this in mind, it is the principal object of the present invention to provide an improved clamp for connecting a hot box detector scanner or other railway equipment to a rail of a railway track.

According to the invention, such a clamp comprises an elongated housing having a platform at one end, electrically insulating and vibration isolator means mounted on the platform, first rail claw means fixed to the housing and facing away from the platform, second rail claw means spaced from and facing towards the first rail claw means, means for urging the first and second rail claw means towards each other to grip the flange of a rail between them and thereby connect the clamp to the rail, and rail cant adjusting means adjacent one of the rail claw means.

In use the clamp is fixed to a rail by means of the rail claw means and adjusted to the rail cant, and the equipment is mounted on the isolator means of the clamp which provides electrical insulation and mechanical shock and vibration isolation from the rest of the clamp and the rail.

The clamp is relatively simple to fit and adjust to a variety of rail sizes and rail cant, and is readily incorporated into existing systerns.

Preferably the isolator means comprises a hollow cylinder, an outer inverted cup secured to one end of the cylinder, an inner inverted cup within the outer cup and secured to the other end of the cylinder, shock absorbing material between the cups and carrying means secured to the platform, fastener means extending through the cylinder for securing the equipment to the clamp, and means for electrically insulating the equipment from the outer cup and from the fastener.

Preferably, the housing has a threaded rod at its end opposite the platform, the second rail claw means is mounted for longitudinal movement along the rod, and a nut is screwed on the rod outboard of the second rail claw means for the purpose of urging the second rail claw means towards the first rail claw means to clamp a rail between them.

The rail cant adjusting means may comprise a nut screwed on the threaded rod between the rail claws and adjacent the second rail claw, the cant adjusting nut preferably having faces which are at unequal distances from the axis of the bore of the nut and thereby permitting cant adjustment of the clamp with respect to a rail when the clamp is fitted to the rail.

An example of a clamp in accordance with the invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a perspective view of the clamp; Figure 2 is an enlarged elevational view of the cant adjusting means of the clamp; Figure 3 is a side view with parts in section, showing the clamp fitted to a rail and carrying a piece of scanning equipment; and, Figure 4 is an enlarged sectional view of a shock isolator of the clamp.

The drawings illustrate a clamp 10 comprising an elongated housing 1 2 having a platform 1 4 at one end thereof. A pair of mechanical shock and vibration isolators 16, 1 8 are attached to the platform 14 by a number of bolts 20. The isolators 16, 1 8 may be commercially available shock mounts, such as Barry isolators.

As shown in Fig. 4, each isolator comprises a cylinder 22 to which a cupped washer 23 and an inverted cup 28 are fixed at opposite ends, the cups being held in position by rolled edges of the cylinder 22. An inverted cup 26 is located between the cupped washer 23 and the cup 28 without touching the cylinder 22, and the cups are separated from each other by a pair of silicone elastomer packings 30 and 32 as illustrated. This material is also an excellent electrical insulator. It is through the flange 38 of the cup 26 that the isolator is bolted to the platform 14. The equipment 40 to be mounted on the isolators 16, 18 is fastened to each isolator by a bolt 24 which extends through the cylinder 22 and co-operate with a nut, access to which is provided by an opening in the platform 14 as shown.The equipment 40 is electrically insulated from the upper cup 28 by an insulator plate 34 formed of a suitable electrical insulation material, such as G-10 fibre glass. Similarly the bolt 24 which secures the equipment 40, such as a scanner, to the isolator is electrically insulated from the equipment 40 by a bush 36 which may also be formed of G-10 fibre glass. As a result, the equipment is fully insulated electrically from the clamp and hence from the rail.

A rail claw 42 formed integrally with the platform 14 and housing 1 2 has a pair of claw members 44, 46 which face away from the isolators and are contoured to receive the outboard flange 48 of a rail 50. A threaded rod 52 extends longitudinally from the housing 1 2 and carries a floating rail claw 54 having a shaped recess 48 facing towards the claw 42 and contoured to receive the inboard flange 60 of the rail 50. A nut 62 and conical washers 64 are provided on the rod 52 for holding the rail claw 54 in a position where the bottom flanges 48, 60 of a rail 50 are gripped tightly between the claws 42, 54 to secure the clamp to the rail as shown in Fig.

3.

In order to correct for the cant of the rail 50, an adjustment nut 66 is provided on the rod 52 between the housing 12 and the claw 54. The nut 66 is in screw-threaded engagement with the rod 52 and therefore may be moved along the rod with any adjustment of the position of the claw 54. As shown in Fig.

2, the nut 66 has external faces 70, 72, 74 and 76 which are positioned at unequal distances from the axis 78 of the nut 66. As a result, by bringing a different external face of the nut 66 into contact with the underside of the rail 50 the clamp 10 may be made to pivot about the edge of the rail flange 48. The degree of rotation is determined by the particular face 70, 72, 74 or 76 of the cant nut 66 that is brought into contact with the bottom surface of the rail which, in turn, is governed by the degree of cant that is to be corrected.

In practice two similar clamps 10 will usually be used to secure a piece of equipment to a rail, the equipment being bolted to each of the four isolators thus provided.

Claims

1. A clamp for connecting equipments to a rail of a railway track, comprising an elongated housing having a platform at one end, electrically insulating and vibration isolator means mounted on the platform, first rail claw means fixed to the housing and facing away from the platform, second rail claw means spaced from and facing towards the first rail claw means, means for urging the first and second rail claw means towards each other to grip the flange of a rail between them and thereby connect the clamp to the rail, and rail cant adjusting means adjacent one of the rail claw means.

2. A clamp according to Claim 1, in which the housing has a threaded rod at its end opposite the platform, the second rail claw means is mounted for longitudinal movement along the rod, and a nut is screwed on the rod outboard of the second rail claw means for the purpose of urging the second rail claw means towards the first rail claw means to clamp a rail between them.

3. A clamp according to Claim 2, in which the rail cant adjusting means comprises a nut screwed on the threaded rod inboard of the second rail claw means.

4. A clamp according to Claim 3, in which the rail cant adjusting nut has faces disposed at unequal distances from the axis of the bore of the nut.

5. A clamp according to any one of the preceding Claims, in which the isolator means comprises hollow cylinder, an outer inverted cup secured to one end of the cylinder, an inner inverted cup within the outer cup and secured to the other end of the cylinder, shock absorbing material between the cups and carrying means secured to the platform, fastener means extending through the cylinder for securing the equipment to the clamp, and means for electrically insulating the equipment from the outer cup and from the fastener.

6. A clamp according to Claim 5, in which the electrically insulating means comprises a sheet of insulating material for location between the equipment and the outer cup, and a bush of insulating material around the fastener.

7. A clamp according to Claim 1, substantially as described with reference to the accompanying drawings.

8. A rail having equipment connected to it by a clamp according to any one of the preceding Claims.