GB2207992A

GB2207992A - Location marking device

Info

Publication number: GB2207992A
Application number: GB08812879A
Authority: GB
Inventors: Brian David Glover
Original assignee: Cytrigen Energy Products & Ser
Current assignee: Cytrigen Energy Products & Ser
Priority date: 1987-06-02
Filing date: 1988-05-31
Publication date: 1989-02-15
Also published as: GB8812879D0

Abstract

A portable self-luminous marking device, suitable for marking outlines of airstrips, helipads, and the like, comprises a plurality of self-luminous light sources 14 embedded in a substantially light permeable resilient material 12, such as silicone elastomer. The light sources may each be received in a protective housing and they may be arranged in rows radiating from a centre, in a dome-shaped marking device. <IMAGE>

Description

LOCATION MARKING DEVICE DESCRIPTION This invention relates to a location marking device and more specifically to a self-luminous marking device which is preferably portable and suitable for marking the outlines of airstrips, helipads, and the like.

Self-luminous light sources, that is, light sources using a radioactive gas and a phosphor coating responsive to the emissions of the gas, are, per se, well-known. Usually, such self-luminous light sources take the form of simple glass tubes coated internally with a phosphor and filled with radioactive gas. The radioactive decay of the gas activates the phosphors and produces light emissions. Various radioactive gases can be employed but tritium is generally used as its low-energy emissions are preferred over the highenergy emissions of other radioactive gases, for example, krypton 85, for reasons of safety. Similarly, various phosphors can be employed, such as, zinc cadmium sulfide, zinc sulfide, zinc silicate, cadmium sulfide, and the like. e Other structures for self-luminous light sources are also known in the art.For example, United States Patent No. 4 546 417 to Watts discloses a cylindrical tube inside a second cylindrical tube defining an annular space between the tubes in which the radioactive gas is sealed. At least one of the surfaces of the cylindrical tubes is coated with a phosphor to produce the light emissions during radioactive decay. United States Patent Nos. 3 038 271 to MacHutchin, 3 566 125 to Linhart, Jr. and 3 005 102 to MacHutchin teach further structures for selfluminous light sources.

Regardless of the structure of the self-luminous light source, in view of the radioactive gas in the internal volume of the light source, extreme care must be taken to ensure that the light source is not broken thereby releasing the radioactive gas. Normally, the self-luminous light source is protected against breakage by a rigid casing made of wood, steel, hardened plastic or other material. These protective casings are typically of substantial volume and weight to adequately protect the light sources from collisions. Thus, such protective casings are typically extremely difficult and inconvenient to relocate, thereby making it impractical to use such self-luminous light sources as portable marking devices.

According to the present invention, there is provided a portable self-luminous marking -device comprising a self-luminous light source or a plurality of such sources embedded in a substantially lightpermeable resilient material. The self-luminous marking device is preferably dome-shaped and is adapted to be positioned where required as by use of standard ballast bags.

The invention is further described. below, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a top plan view of a first marking device embodying the invention, having a group of selfluminous light sources in a moulded medium, Figure 2 is a cross-sectional view taken along the line 2-2 of Fig. 1, Figure 3 is a side elevation showing the device of Fig. 1 connected to a coupling to elevate it above ground level, Figure 4 is a side elevation showing the device of Fig. 3 in a ballast bag, Figure 5 is a top plan view of a second marking device embodying the invention, having a group of housing assemblies (each containing a self-luminous light source - not shown) in a moulded medium, Figure 6 is a cross-sectional view taken along the line 6-6 of Fig. 5, Figures 7a and 7b are perspective views of a lens and base, respectively, which combine (the lens fitting over the top of the base) to form a protective housing assembly for containing a light source, Figure 8 is a top plan view of two straps, arranged in a cross-shape overlapping relationship, for receiving and securing housing assemblies containing light sources, and Figure 9 is a top plan view of the strap of Fig. 8 with a number of housing assemblies secured thereto.

The marking device of the present invention may be of many suitable structures and shapes. It will be appreciated that each location and end use will require different levels of light and geometries of marking devices which, of course, will affect the final shape of the moulded unit. The invention is described below with reference only to preferred portable marking devices structured for use in a helicopter landing area and this is to be understood to be by way of example only.

Shown in Figures 1 and 2, a self-luminous marking device 10 is generally dome or hemispherically-shaped.

The device 10 is made of a light-permeable resilient material 12, preferably silicone elastomer in which are embedded a plurality of self-luminous light sources 14 and a mounting bracket 16.

The resilient material 12 is formed in an inner zone 18 and an outer zone 20. The mount 16 is embedded in the inner zone 18 and the self-luminous light sources 14 are embedded in the outer zone 20. The mount 16 comprises a pipe coupling 22, a cap 24 and a plurality of lugs 26.

The first zone 18 is prepared in a hemispherical mould by mixing the base material and curing agent of the resilient material 12 together and inserting the mount 16 while the resilient material 12 is still liquid. The resilient material 12 is then allowed to cure with the mount 16 embedded therein.

In order to prepare the zone 20, the self-luminous light sources 14 are first cured in a small amount of resilient material 12 with reflective backings 28. The light sources 14 with their reflective backings 28 are positioned on the outside of the zone 18 and a second, larger hemispherical mould is filled with base material and curing agent. The zone 18 with the positioned light sources 14 is then placed in the larger mould while the resilient material 12 is still liquid and allowed to cure in the position shown in Figure 2.

When cured, the resilient material 12 is substantially light-permeable and the light sources are fully visible.

A second embodiment of the invention, providing individual protective housing assemblies for each light source within the resilient material, is illustrated in Figures 5 - 9 of the drawings. In this embodiment, a first zone 18 is formed according to the above description with respect to Figures 1 and 2 but preferably the mount 16 also comprises a hard plastic disk 27 providing an aperture (not shown) through which the mixture of base material and curing agent is poured into the mould while still in a liquid state.

To prepare the outer zone 20, the light sources 14 are placed in a hard plastic base 50 which is made from or contains a light reflective material. The light source 14 is held in position in the base 50 by a small amount of light-permeable resilient material 12. A hardened clear plastic lens 53 is affixed over and to the base 50 after the light source 14 is secured to the base 50, the combination of the base 50 and lens 53 forming a protective housing assembly 55 around the light source 14.

To ensure accurate placement of the protective housing assemblies 55 (and light sources 14 within them) the bases 50 are formed with two projections 60 which project below the base 50 and are configured to securely fit into matching holes (or recesses) 62 in a flexible strap 57. As shown in Figure 8 strap 57 is also made with holes 64 and projections 66 to permit another length of strap 57 to be perpendicularly secured to the first length of strap 57 so as to form a main array 68. Additional smaller lengths of strap 57 may be used to provide intermediate array(s) as desired. The arrays are than affixed to the prepared first zone 18 and the combination of the first zone 18, straps 57, housing assemblies 55 secured to the straps 57 and light sources 14 within the housing.assemblies 55 is placed in a second larger hemispherical mould filled with liquid base material and curing agent. The liquid is then allowed to cure so as to form the outer zone 20 around the first zone 18.

In use, a plastics pipe 30 with a base platform 32 is inserted in the mount 16 (see Figure 3). When on site and ready to use, the pipe 30 and the base 32 are received in the neck 34 of a ballast bag 36 (see Figure 4). A gear-type house clamp 38 is tightened to secure the neck 34 of the ballast bag 36 securely to the pipe 30. Locally available ballast, example, stones and sand, is loaded into the ballast bag 36, through pockets 40, and rests on the base 32. When filled, the pockets 40 are closed and secured with fasteners 42.

Where further securing is desired or where no suitable ballast is readily available, the ballast bag 36 may be secured by ropes 44 held down by weights' 46 or pegs 48.

It will be appreciated that the self-luminous marking devices can be moulded in a variety of shapes and configurations and mounted by many different means suited to the particular application. All such embodiments are within the scope of the present invention as defined by the following claims.

Claims

1. A location marking device comprising at least one self-luminous light source embedded in a substantially light permeable resilient material.

2. A marking device as claimed in claim 1 having a plurality of the light sources arranged in one or more rows.

3. A marking device as claimed in claim 2 having a plurality of the rows of light sources, the rows extending radially from a centre.

4. A marking device as claimed in claim 1, 2 or 3 wherein the or each light source is contained within a protective housing, the light source and housing being embedded in the resilient material.

5. A marking device as claimed in claim 4 wherein the or each housing comprises a hard plastics base and a clear lens fixed to the base after securement of the light source in the base.

6. A marking device as claimed in claim 5 wherein the base is made of or contains a light reflective material.

7. A marking device as claimed in claim 4, 5 or 6 wherein the housings are shaped so as to be located on an elongate mounting member.

8. A marking device as claimed in claim 7 wherein the housings are provided with locating projections or recesses and the mounting member is provided with cooperating recess or projections.

9. A marking device as claimed in claim 7 or 8 wherein the mounting member comprises a flexible strap.

10. A marking device as claimed in any preceding claim having a reflective backing for the or each light source.

11. A marking device as claimed in claim 10 wherein the light sources are embedded in an outer zone of the device, and a mounting bracket or member for the device is embedded in an inner zone of the device.

12. A marking device as claimed in claim 11 wherein the mounting member comprises a pipe coupling.

13. A marking device as claimed in claim 12 having a pipe received in the pipe coupling and ballast means located around the pipe.

14. A marking device as claimed in any preceding claim wherein the resilient material is a silicone elastomer.

15. A location marking device substantially as herein described with reference to Figures 1 and 2 or Figure 5 - 9.

16. A location marking device as claimed in claim 15 when mounted substantially as described with reference to Figure 3 or Figure 4.