GB2392765A

GB2392765A - Connector for attaching a signal detonator to a rail

Info

Publication number: GB2392765A
Application number: GB0218281A
Authority: GB
Inventors: John Edward Jennings
Original assignee: Individual
Current assignee: Individual
Priority date: 2002-08-07
Filing date: 2002-08-07
Publication date: 2004-03-10
Also published as: GB0218281D0

Abstract

A detonator clip for securely locating a signal detonator on an elongate rail (11), consisting of a base (14), retainment means (20) removably to hold the detonator (21) above the rail and resiliently deformable legs (16, 17) that bear upon opposite sides of the rail. This clip may be securely and easily attached to and removed from the rail many times, and on an assortment of different-sized rails, such that the detonator is appropriately positioned and detonates when a train passes over it. The retainment means preferably consist of a pair of arms extending upwardly from the base with ridges (22) that bear on the detonator. The connector may be formed from plastics material, by injection moulding.

Description

- - 2392765

Connector The present invention relates to connectors for removably locating signal detonators on elongate rails.

When work is carried out on railway lines, various systems and products are used to protect the workers from injury caused by trains accidentally running along the lines that are being worked upon. These include, as a final line of defence, generally flat signal detonator caps, a series of which are placed on the rails before the work location. If a train passes the 10 previous warning signals, the wheels of the train will pass over the detonators and cause them to fire off loud audible warnings. This alerts both the train driver and the workers to the dangerous situation and allows appropriate action to be taken.

To ensure the train's wheels reliably set off the detonators, it is 5 essential that the detonators are securely located on the rails. Furthermore, as the detonators represent the final fail safe device they are rarely set off, so they may be removed and used again at different sites. Unfortunately the present means of attaching the detonators to rails comprise a malleable metal strip, which is integrally formed with the detonator and may be bent around a 20 rail to locate a detonator thereon - and this existing technology has several major limitations.

Firstly, the strip must be carefully bent around a rail to fix the detonator, which is time consuming, and results in a less then satisfactorily secure fixing.

Secondly, and most importantly, the metal strips suffer fatigue (particularly at the point where they are connected to the detonator) as a result of repeated

- 2 ( bending. Consequently they break off after a relatively short period of time, thus preventing reuse of the detonators. Typically, the detonators have a certified life of 5 years, after which they must be replaced, but the metal strips typically last only a few months, after which the detonator is discarded (as it 5 may no longer be affixed to the rail) despite having a long period of remaining efficacy. Consequently, it is an aim of the present invention to provide a mechanism by which detonators may be securely and easily attached to and removed from a rail many times. It is a further aim to provide a device that to allows a conventional detonator to be attached to a rail once the metal strip has broken off, and even before then.

Therefore, according to the present invention there is provided a connector for securely locating a signal detonator on an elongate rail, which connector comprises a base, attachment means for removable engagement of 15 a detonator with the connector such that in use the detonator is located above the upper surface of the rail, and a pair of resiliently deformable legs extending downwardly from the base and adapted to bear upon opposite sides of the rail to securely locate the connector and detonator thereon.

The attachment means must securely hold the detonator in place, but 20 must permit the selective attachment and disengagement thereof when desired. It is preferred that the attachment means includes a pair of arms extending upwardly from the base. Such arms might be adapted to hold opposite parts of the detonator against the upper surface of the base, between a lower surface of the arms and an upper surface of the base. In 25 general the detonators are disc-shaped and it has been found that it is best

- 3 f that the arms extend up the sides and over at least part of the upper surface of the detonator. To achieve this the arms may have a first part extending away from the base and a second part extending generally parallel to the base, and indeed the upper surface of the detonator.

5 To assist in securely locating the detonator, the upper surface of the base and/or the lower surface of the arms may be provided with raised parts.

These may take the form of ridges or nodules that bear on the detonator, or cooperate with formations thereon.

As mentioned above, current detonators are generally round or disc 10 shaped and it is preferred that the connectors are specially adapted to locate such conventional detonators by appropriate configuration of the base and connection means.

The connector may be provided with a base that is as large or larger than the area of the detonator, but this is generally not necessary. Instead 15 conveniently the base and legs have a width (i.e. in a direction parallel to the length of the elongate rail) less than the diameter or width of the detonator.

The base and the legs may be integrally joined and the legs may be formed from parts that are bent at an angle to the base. Such a connector with two opposed arms may conveniently locate a detonator on a rail, with the 20 minimum of material cost involved in the construction of the connector.

The connector may in certain embodiments be advantageously provided with more than two arms. Also the connection means might take other suitable forms such as an annular holder into which the detonator locates.

- 4 ( A significant advantage of the present invention is that the connector may be used on a variety of different rails, because the legs may be adapted to grip a variety of differently-shaped and sized rails, as a consequence of their resilient deformability. The legs would normally be relatively close 5 together when the connector is not located on a rail, but when they are passed over the rail they are forced outward such that they grip the sides of the rail.

The connector may of course be formed from a variety of materials or combinations of materials. However, it is preferred that it is formed 10 substantially wholly from plastics material, and furthermore that it is formed from such material by moulding techniques such as injection moulding.

In order that it may be better understood, but by way of example only, the present invention will now be described with reference to the accompanying drawings in which: Figure 1 is a cross section through a rail showing an embodiment of the present invention connected thereto; Figure 2 is a side view of the embodiment of Figure 1 not showing the rail; and Figure 3 is a plan view of the same embodiment again showing the 20 rail.

Referring simultaneously to all three Figures there is shown a connector generally indicated 10 for location on a rail 11 (top part only shown in Figure 1 and Figure 3, but not shown at all in Figure 2). The connector comprises a generally rectangular base 14, which in use locates on the upper 25 ride surface 15 of the rail 11. Extending downwardly from the ends of the

- 5 ( base 14 are opposed legs 16 and 17, which are angled inward but are resiliently deformable such that they may move outward so as to be located around the rail 11 from above. The outer end 19 of each leg is thickened to prevent damage when locating over the rail. The outer ends 19 shown in this 5 embodiment represent the narrowest part of the throat, but the legs might instead have a more s-shaped profile such that the narrowest gap between the legs is at a point above the bottom. Such splaying of the outer ends would further aid connection of the connector to a rail.

Two opposed retaining arms 20 extend above the upper surface of the 10 base 14. A first part of each extends away from the base at an angle, and a second outer part extends essentially parallel to the base. A discshaped detonator 21 is locatable between the arms 20 and the base 14, the distance between the lower surface of the arms and the upper surface of the base 14 being such that the detonator is a resilient fit therebetween. A detonator may 15 be slid in and out sideways, generally in the plane thereof, for connection and disconnection, but the detonator is a tight enough fit that it will not accidentally become disengaged. To improve the inter-engagement of the detonator 21 and connector 10 the upper surface of the base 14 is provided with raised ridges 22, and the free- ends 23 of the arms 20 are thickened.

20 In use, a detonator 21 is located on a connector 10, by sliding it between the arms 20 and the base 14. The combination is then connected to an elongate rail from above by displacing the legs 16, 17 outwardly such that they will pass over the rail and then allowing them to resiliently grasp either side of the rail. This will securely hold the detonator 21 above the rail 11 such 25 that a train running along the track will set the detonator off. The reverse of

- 6 this process may achieve removal of the connector 10 from the rail 11 and the detonator 21 from the connector 10.

Should a connector break, which is far less likely than with the existing technology, a replacement may be used to continue the useful life of the same 5 detonator. Similarly, should the detonator pass its use by date, it may be discarded, but the connector may continue to be used.

Clearly the present invention has been described predominantly with reference to connection of a standard shaped and sized detonator. However the connections means may be adapted to accommodate a variety of 10 differently sized detonators, should the standards alter in the future.

Claims

- 7 Claims

1. A connector for securely locating a signal detonator on an elongate rail, which connector comprises a base, attachment means for removable 5 engagement of a detonator with the connector such that in use the detonator is located above the upper surface of the rail, and a pair of resiliently deformable legs extending downwardly from the base and adapted to bear upon opposite sides of the rail to securely locate the connector and detonator thereon. Jo

2. A connector as claimed in claim 1, wherein the attachment means includes a pair of arms extending upwardly from the base.

3. A connector as claimed in claim 2, wherein the arms are adapted to hold the detonator against the upper surface of the base.

4. A connector as claimed in either of claim 2 or claim 3, wherein the arms 5 have a first part extending away from the base and a second part extending from the first part generally parallel to the base.

5. A connector as claimed in any of claim 2 to claim 4, wherein the upper surface of the base and or a lower surface of the arms are provided with raised parts that assist in securely locating the detonator.

20

6. A connector as claimed in any of the preceding claims, in which the base and connection means are adapted to locate a generally circular detonator.

7. A connector as claimed in claim 6, wherein the base and legs have a width parallel to the length of the rail, that is less than the diameter of the 25 detonator.

( -

8 8. A connector as claimed in any of the preceding claims, in which the legs are adapted to grip a variety of differently-shaped rails.

9. A connector as claimed in any of the preceding claims, in which when not located on a rail, the distance between the legs is less than when the 5 connector is located on a rail.

10. A connector as claimed in any of the preceding claims, which is formed from plastics material.

11. A connector as claimed in any of the preceding claims, which is formed by injection moulding.

to

12. A connector as claimed in claim 1 and substantially as herein described with reference to and as illustrated in the accompanying Figures.