AU662936B2

AU662936B2 - A sign and signal which resists destruction from rifle and gunshot fire

Info

Publication number: AU662936B2
Application number: AU28280/92A
Authority: AU
Inventors: John F. Brennan
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-11-12
Filing date: 1992-11-12
Publication date: 1995-09-21
Anticipated expiration: 2012-11-12
Also published as: AU2828092A

Description

P/00/O11 281VS91 Regulation 3,2

AUSTR-ALIA

Patents Act 1990 6 29

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: AA/4''tCAI~ srs following statement is a full description of this invention, including the best .J.nethod of performing it known to me:- A sign and signal which resists destruction from rifle and gunshot fire.

This invention relates to the protection of signs and signals from damage by rifle and gunshot fire.

Road signs are frequently 'shot up by vandal shooters. The signal is defaced by holes and chipped paint from rifle and gunshot fire. Daylight can be seen through the holes, O and paint chipping from grouped rounds and shot renders signals unclear and unsightly. Road signs have great appeal as targets for vandal shooters.

This invention by the use of neoprene laminate overcomes the problems of holes and paint chipping. Target appeal is negated. Entrance holes through neoprene contractdown. Experiments confirm that an 8 to 10 mm hole is S reduced to 2 mm. Scattered patterns of shot do not S. disrupt the signal and leave small entrance holes not visible at a distance. Bullet entrance holes are not visible at 15 metres. The signal remains intact after the passage of many rounds.

Experiments were conducted with rifle and gunshot fire at metres distance from the signs. Twenty two calibre long rifle hollow point bullets were tested because these are the favoured anmunition of the rifle shooter. Some tests were conducted with 22 calibre solid nose long rifle bullets.

A four ten gauge shotgun of full choke was also used. It fired super X long range shotgun shells of 7.6 cm No. 4 shot. In terms of damage to the signal the findings were much in favour of the inventicn described below: With a conventional sign, one single shot from a shot gun cartridge denuded an area of at least 6 to 7 mm of signal face; two shot pellets denuded areas up to 2 cm across. A grouped pattern of nine shot pellets denuded areas of 6 10 cm across. The metal surface of the sign was indented by each shot pellet.

S

The signal on the invention was not disrupted by shotgun fire to any significant extent. It exhibited small holes of 0.5 mm diameter with a surrounding depressed corona.of total diameter 1.5 mm. The shot embedded in the plywood layer at 5 to 7 mm depth.

With regard to rifle fire the conventional sign showed 8 to 9 mm holes in diameter with surrounding indentation and ragged denuding of signal paint. A group of two rounds in close proximity gave a gash of 2 cm width surrounding indentation and denuding of the signal. This gash is akin to gashes seen on road signs.

Damage from rifle fire was much lessened on the invention tested. Both solid and hollow point rifle rounds showed entrance holes of 2 mm diameter with surrounding coronal dents of 2 to 3 mm outer diameter. Grouped rounds in 4 close proximity caused no gashing of the signal, instead they appeaied as separate entrance holes of the same diameter aforementioned. The signal remained clear and mostly intact after repeated rounds.

The sign is made of three layers: a supporting backing plate of sheet aluminium a middle sheet of 6.4 mm plywood a sheet of single ply neoprene-commercial grade ~The layers are cemented together with panel adhesive gel under pressure. The message or signal. is applied direct to the neoprene sheet by painting, transfer or sticker.

A simple form consists of an aluminium backing plate S supporting a layer of neoprene sheet. A nutmber of materials can be used for a backing plate and middle Slayer. When aluminium sheet and neoprene are employed alone, that is without the interposed layer of ply;ood, "the results are good for rifle fire and gunshot pellets •ere•: but a phenomenon of shot entrapment arises. The shot after passing through the neoprene comes to rest approximately 1 cm distant from its entrance hole. Shot entrapment gives rise to smooth local bulging. The signal remains clear. Shot entrapment bulge is not visible at metres. The signal withstands multiple attacks.

Shot entrapment is eliminated by interposing the plywood layer. A sign made from industrial plywood and neoprene alone did not exhibit shot entrapment. Another form of the sign consists of stretched metal mesh overlaid by adherent neoprene sheet. This would have some advantage in the reverse shooting up of signs which at present is not that frequent.

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Claims

1. A sign and signal resisting destruction from rifle and gunshot fire and being composed of sheet aluminium overlaid by a sheet of plywood which in turn is overlaid by Neoprene sheet made adherent and displaying the signal.

2. A sign and signal as in claim one ii where the signal is painted direct to the prepared surface of neoprene.

3. A sign and signal as in claim 1 where the signal is applied by transfer or sticker to the neoprene.

4. A sign and signal as in claim 1, 2, and 3 where the middle layer is of suitable material other than plywood. SJ F BRENNAN 7 'C'