GB2187268A - Protective screen - Google Patents

Abstract

A protective screen comprises a self-standing screen member 1 which includes an outer layer of plate steel 2, spaced from an inner barrier 3 of plate steel 4 and 5 spaced apart by a wooden sleeper infill 6. The outer layer of steel 2 is formed of four inwardly sloping rows of plates 7, 8, 9 and 10 mounted on frames 11 and 12. Base skids 21 are also provided. A trailer for use in transporting the screens is also provided. The screen in use provides protection against explosive blasts and projectiles. <IMAGE>

Description

SPECIFICATION Protective screen This invention relates to a protective screen for use in protecting personnel engaged in work adjacent areas where there is a possibility of explosion due to mines, bombs or the like.

In time of war, airfields provide vital facilities for aircraft being used either in defence or attack. For this reason airfields are attractive targets for attacks by enemy forces due to the considerable effect on a force's aircraft capability that a successful attack can produce.

It is important, therefore, that an airfield is repaired as quickly as possible after such an attack.

Repair teams work to re-establish a minimum operating strip on damaged runways which will allow aircraft to take off and land.

However, an attack on an airfield may involve the use of bombs and minelets. The bombs explode on impact with the ground but the minelets remain after the attack to provide a continuing hazard for repair teams. As airfields are normally flat and fragments from an exploding mine are dangerous up to a radius of one thousand metres in direct line of sight from the mine, a large area of ground surrounding the desired line of the minimum operating strip must be cleared of mines before repair work can commence.

This adds considerably to the total time required to bring an airfield back into operation following an attack.

According to the present invention there is provided a protective screen for absorbing or deflecting the force of a blast or projectile comprising an upstanding self supporting support member having secured thereto a barrier for resisting penetration by projectiles.

Preferably, the protective screen is provided with a plurality of layers of armoured material.

The layers may be formed of steel and may incorporate a layer of wood. preferably also, the outer surface of the screen member is angled so as to deflect the force of a blast upwards.

Preferably also, an air gap is provided between the two outermost layers of armoured material to minimise the effect of heat created by a blast.

Preferably also, the end portions of the screen member are provided with engagement means so that the screen member may engage adjacent screen members to form a continuous, interfitting barrier.

Preferably also, a pair of screen members may be connected to one another in a spaced back-to-back arrangement.

Preferably also, the screen member may be mounted on a sledge unit. The sledge unit facilitates transport of the screen member between sites.

The sledge unit may be in the form of a trailer and may be provided with hydraulic lift means which engage lifting members provided on the screen member. The trailer may also be used to transport aircraft.

Embodiments of the present invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a pair of protective screens in accordance with a first embodiment of the present invention; Fig. 2 is a perspective view of the end portions of the protective screens of Fig. 1; Fig. 3 is a side view of the inside of one of the protective screens of Fig. 1; Fig. 4 is a sectional end view of the protective screens of Fig. 1; Fig. 5 is an exploded perspective view of the protective screens of Fig. 1; Fig. 6 is a sectional plan view on line X-X of Fig. 3; Fig. 7 is a sectional end view of a pair of protective screens in accordance with a second embodiment of the present invention; Fig. 8 is a plan view of the protective screens of Fig. 7;; Fig. 9 is a sectional side view on line A-A of Fig. 7; Figs. 10 and 11 are side and front views of a first example of a trailer for use in transporting protective screens; Figs. 12, 13 and 14 are plan, side and end views of a second example of a trailer for use in transporting protective screens; Fig. 15 is a plan view of the bogies of the trailer of Figs. 12, 13 and 14; Figs. 16, 17 and 18 are plan, side and end views of a third example of a trailer for use in transporting protective screens; Fig. 19 is a plan view of the bogies of the trailer of Figs. 16, 17 and 18; Fig. 20 is a perspective aerial view of an airfield repair operation using protective screens in accordance with the present invention; and Fig. 21 is a plan view of an airfield showing the positioning of protective screens to provide protection against attack from aerial launched rockets.

Referring to Figs. 1 to 6 of the drawings a first embodiment of a protective screen comprises a self-standing screen member 1. The screen member 1 is ten metres long and four metres high and includes an outer layer of 5mm plate steel 2, spaced from an inner barrier 3 having two layers of 5mm plate steel 4 and 5 spaced apart by a wooden sleeper infill 6.

The outer layer of plate steel 2 is formed of four inwardly sloping rows of plates 7, 8, 9 and 10. The plates 7, 8, 9 and 10 are mounted on frames 11 and 12. The frame 11 on which the two uppermost plates 7 and 8 are mounted extends into an upper section 13 of the inner barrier 3. The frame 11 provides rectangular openings 14 and 15 at the upper and lower edges of the section 13.

The opening 15 in the lower edge of the section 13 receives one end portion of an elongate connection member 16, the other end of which is received by a complementary opening 17 in the upper edge of a lower section 18 of the inner barrier 3. The connection member 16 is secured in the openings 15 and 17 by means of retaining pins. The opening 17 is provided by the frame 12 which extends through the lower section 18, an opening 19 also being provided by the frame 12 at the lower edge of the section 18. The opening 19 receives connection members 20 which extend upwardly from a base skid 21 which is fitted to the base of the screen member 1.

Retaining pins are provided to secure the member 20 in the opening 19.

A portion 22 of the frame 12 extends through the inner barrier 3 to support a length of angle iron 23 which extends parallel to the barrier 3 to provide a lifting point for the screen member 1. In this embodiment each screen member 1 is provided with six each of frames 11 and 12, and the angle iron 23 is attached to the extending portions 22 of each frame 12.

Tightening bottle screws 24 extend from connecting plates 25 on the extending portions 22 of the frames 12 to engage with connecting plates 26 which extend from the frames 11 in the upper section 13 of the barrier 3.

In this embodiment two screen members 1 are connected to one another by means of cross ties 27 and 28 to form a more substantial barrier.

Four base cross ties 27 are provided and are fixed at their ends to the base skids 21 of the screen members 1.

The roof cross ties 28 extend between the upper edges of the sections 13 of the barriers 3, and have downwardly extending end portions 29 which are received by the openings 14 and secured in place by retaining pins.

Additional diagonal and perpendicular strengthening ties 30 and 31 extend between the cross ties 28 to provide additional rigidity for the structure.

One end of each of the screen members 1 is provided with a tapered flange 32 which extends from the end of the screen to locate within an adjacent barrier 33, as is shown in Fig. 2. The flange 32 is mounted on the end of a wedge-shaped plate 34 which is fixed to the face of the barrier 3. The flange 32 and plate 34 are formed of two portions 35 and 36 each being fixed to the upper and lower sections 13 and 18 of the barrier 3.

The second embodiment of the protective screen as is shown in Figs. 7, 8 and 9 is substantially similar in construction to the first embodiment described above, corresponding parts of the second embodiment being allocated the reference number previously used in the description of the first embodiment, plus a factor of 100.

However, in the second embodiment the extending frame portions 122, which, with the longitudinal member 123, form a lifting frame are attached to the lower section 118 of the barrier 103 and are not attached to the frame 112.

Also, in the second embodiment the outer steel plates 107, 108, 109 and 110 are positioned vertically on the mounting frames 111 and 112.

Towing eyes 137 are provided in the base skids 121 to permit towing cables from tractor units to be attached to the screens.

Now referring to Figs. 10 and 11 of the drawings a first example of a trailer for use in transporting protective screens comprises a trailer deck 40, mounted on a support frame 41 which is in turn mounted on two bogies 42 and 43.

The trailer deck 40 is connected to the frame by eight hydraulic jacks 44 which may be extended to raise the deck 40. Hydraulic connection hoses 45 are provided for connection to the hydraulic supply of a tractor unit.

The bogies 42 and 43 are each provided with three ten ton axles 49 having double pneumatic tyres 46 encased in tracks 47. The front bogie 42 is pivotally connected to the frame 41 and is provided with a bracket and eye 48 for connection to a tractor unit.

Now referring to Figs. 12 to 15 of the drawings a second example of a trailer for use in transporting protective screens comprises a trailer deck 140, mounted on support frames 141A and 141B which are each mounted on bogies 142 and 143.

Each frame 141A and 141B is connected to the deck 140 by four hydraulic jacks 144 arranged in groups of two, parallel to and on either side of the main longitudinal axis of the deck 140.

Extension of the jacks 144 raises the deck 140 from the frames 141A and 141B.

Each bogie is provided with five axles 149 carrying sets of double pneumatic tyres 146 encased in tracks 147.

The third example of a trailer, as shown in Figs. 16 to 19 of the drawings, is provided with hydraulic jacks 244 which are arranged perpendicular to the main longitudinal axis of the trailer deck 240.

Now referring to Fig. 20 of the drawings which shows a perspective aerial view of an airfield repair operation. The airfield has been subject to attack by aircraft using bombs, resulting in craters 60, and minelets which do not explode on impact but remain on the ground.

In order to bring the airfield into operation as quickly as possible a minimum operating strip is repaired on the runway 61.

Initially mine clearing units 62 equipped with flails 63 clear an area 64 of runway 61 on which repair work is to commence. The area 64 is then surrounded by screen members 1.

The screen members may be brought singly on trailers 65 and positioned by a crane 66 or may be dragged, in pairs 67, by tractor units 68. The tractor units 68 are conventional 200 horsepower units, provided with either pneumatic tyres or tracks and twenty ton winches.

When the screens 1 are positioned around the area 64 repair work can commence while mine clearing continues on the other side of the screens 1, the screens 1 protecting personnel repairing the runway 61 from exploding mines.

Fig. 21 of the drawings illustrates how screen members 1 may be positioned on an airfield to provide protection for the runway from aerial rocket attacks.

Screen members 1 may also be used to provide a protective shelter around aircraft.

If an unexploded bomb is discovered in an airfield after an attack screens 1 may be positioned around the bomb permitting normal activities to be carried out at the airfield while the bomb is made safe.

Modifications and improvements may be made without departing from the scope of the invention.

Claims (11)

1. A protective screen for absorbing or deflecting the force of a blast or projectile comprising an upstanding self supporting support member having secured thereto a barrier for resisting penetration by projectiles.

2. A protection screen as claimed in Claim 1, wherein the barrier comprises a plurality of layers of armoured material.

3. A protective screen as claimed in Claim 1 or 2, wherein the outer surface of the barrier is angled so as to deflect the force of a blast upwards.

4. A protective screen as claimed in any one of the preceding Claims, wherein the barrier includes an air gap.

5. A protective screen as claimed in any one of the preceding Claims, wherein the screen includes means for engaging an adjacent screen to form a continuous barrier.

6. A protettive screen as claimed in any one of the preceding Claims, wherein a pair of barriers are included in spaced back to back arrangement.

7. A protective screen as claimed in any one of the preceding Claims, wherein the screen is provided with ground engaging transport means.

8. A protective screen as claimed in Claim 7, wherein the ground engaging transport means comprises trailer apparatus provided with skis, wheels or tracks.

9. A protective screen as claimed in Claim 8, wherein the trailer apparatus includes hydraulic lifting jacks for the screen.

10. A protective screen substantially as hereinbefore described with reference to Figs 1 to 6 in combination with a) Figs 10 and 11 or b) Figs 12 to 15 or c) Figs 16 to 19 of the accompanying drawings.

11. A protective screen substantially as hereinbefore described with reference to Figs 7 to 9 in combination with a) Figs 10 and 11 or b) Figs 12 to 15 or c) Figs 16 to 19 of the accompanying drawings.