GB2321951A

GB2321951A - Screen penetrating projectile with extraction device

Info

Publication number: GB2321951A
Application number: GB9702584A
Authority: GB
Inventors: Reeve John William Newtown
Original assignee: Accles and Shelvoke Ltd
Current assignee: Accles and Shelvoke Ltd
Priority date: 1997-02-07
Filing date: 1997-02-07
Publication date: 1998-08-12
Also published as: GB9702584D0; DE19804820A1

Abstract

A device for penetrating a screened opening such as a window (12). A projectile (11) is fired from a captive bolt gun (10) whose muzzle is in contact with the window (12). The projectile (11) remains in engagement with the gun (10) after penetration of the window (12) and following reposition of the gun (10), the gun (10) and the projectile (11) may be used to pull out the window frame (13) or other parts of the window (12).

Description

1 Screen penetrating nr!pjectile with extraction device 2321951 This

invention relates to devices for facilitating rapid entry into buildings or the like through a screened opening such as a window or door.

Openings may be covered by laminated or security glass or other screen materials, typically held within a screen surround or frame, which are difficult to penetrate. Further, even when penetrated, the remainder of the screen may remain intact, thus making it difficult to permit rapid entry of personnel into buildings fitted with such screens. Unless the complete screen or a substantial part of it is removed rapidly, any advantage of surprise may also be lost.

It is one object of the present invention to provide means enabling rapid entry to be made through openings covered by such screens.

Captive bolt guns are well-known. Such guns typically have a spring-loaded firing assembly which is adapted to strike and fire a cartridge loaded within the breech of the gun. Gas pressure generated on the ignition of the cartridge propels a captive bolt through the muzzle of the gun, but the end of the bolt which typically has a portion of enlarged diameter, is retained within the breech by an energy-absorbing device or buffer. The outer end of the bolt is thus only projected a short distance from the muzzle. This type of gun is used in the humane killing of animals for human consumption.

According to one aspect of the present invention a device is provided for penetrating a screen and permitting partial or full removal of said screen or a surround enclosing said screen, the device 1 2 comprising projection means adapted to receive a captive projectile, said projectile having means for penetrating said screen when the projectile is launched from said projection means in a position adjacent said screen, the projectile further having laterally extending location means adapted to be positioned behind still-extending portions of said screen or the screen surround following penetration, such that withdrawal of the captive projectile and/or its projection means may act to remove all or part of said still extending screen or said screen surround.

The projection means may have a muzzle from which said projectile is launched, which muzzle in use is located on or adjacent to the screen, the projection means and/or the projectile being adapted to ensure that the penetrating portion of the projectile is spaced from the screen prior to the actuation of the device.

The projectile may extend longitudinally within the projection means and the projection means and/or the projectile is/are adapted to ensure that the projectile does not rotate about such longitudinal axis relative to the projection means.

The penetrating and locating features of the projectile may be formed by the head of a T-shaped projectile or bolt, the leading or front edge of the projectile performing the penetration function and the arms of the T performing the locating function after penetration of the screen.

The leading edge of the projectile may be centrally located on the Tshaped projectile. The pointed edge may have bevels extending on either side towards the ends of the arms of the T.

3 The arms may have spikes or similar projections on their reverse sides which can engage the reverse side of a screen or screen surround after penetration of the screen and subsequent rotation of the projection means.

The projection means may incorporate attachment means such as one or more eye bolts enabling a cable or a bar to be attached to the projection means. In use, the other end or ends of such cables or bars may be attached to a winch or a vehicle to facilitate the withdrawal of the projection means and its projectile after it has been fired.

The device may be actuated by a trigger located on the exterior of the projection means. The attachment means is preferably located on the projection means such that an attached cable or bar extending in a direction away from the screen does not obstruct manual access to the trigger.

Preferably means is provided to enable the projectile to develop free flight before striking the screen. One way of achieving this is by controlling the length of the projectile and partially cutting away the muzzle at its exit end such that the arms of the T-shaped portion of the projectile extend substantially parallel to the plane of such a cut, the leading edge of the projectile being maintained a predetermined distance from the exit end of the muzzle.

One embodiment of the invention will now be describedl by way of example only, with reference to the accompanying drawings ir. which:- 4 Figure I shows in side elevation and in cross-section a device according to the invention located against a screen to be penetrated, and Figure 2 shows schematically the device of Figure I in a first position A relative to a screen and in a subsequent second position B 5 relative to the same screen after its penetration by the device.

As seen in Figure 1 the device comprises a projection means or gun 10 and a projectile I I with the device located against the outer surface of a screen or window 12. The window 12 has a surround or frame 13 - see Figure 2.

Gun 10 is similar to captive-bolt guns used in the humane killing of animals. It has a chamber 14 in which a cartridge (not shown) is located, and a firing cap assembly 15 and safety mechanism 16 known per se in previous captive-bolt guns. Firing of the cartridge is actuated by a pressure trigger 17 located on the exterior of the gun adjacent the firing cap assembly 15.

Extending forwardly of and co-axial with chamber 14 is an annular breech 18 to which the firing cap assembly 15 is secured in screw-threaded manner. A longitudinally-extending muzzle 19 is coaxially mounted by screw-thread onto breech 18. An annular energy absorbing buffer assembly 20 is located between breech 18 and a shoulder 21 within muzzle 19.

The end 22 of the muzzle 19 remote from breech 18 is cut or machined away over a short length such that less than half its diameter remains in place. It is this cut-away end which is positioned against the sheet of glass.

Projectile 11, which is made of high tensile steel, comprises a bolt 23 co-extending within breech 18 and muzzle 19. On the end 24 of bolt 23 remote from chamber 14 are two co-planar laterally extending identical arms 25, the bolt 23 and arms 25 forming a T-shaped projectile. The forward portion of the arms is bevelled to form a pointed edge 26 at their midpoint. Spikes 27 are located on the rearward portion of the arms towards their radially outer ends (relative to the longitudinal axis of the projectile 11).

Bolt 23 has a flat machined along part of its circumferential surface which cooperates with a flat within a split collar 28 which is located in the muzzle 19. The cooperating flats act to prevent rotation of bolt 23 so that the arms 25 of projectile I I always remain in the same plane relative to the gun 10.

The length of bolt 23 and the forward extension of arms 25 is such that the front edge 26 of arms 25 is spaced inwardly from the end 22 of muzzle 19. When gun 10 is fired, bolt 23 is driven forward within chamber 18. Bolt 23 and arms 25 thus have free flight until edge 26 strikes the front of window 12. This significantly reduces recoil on the gun 10.

It should be noted that bolt 23 can only move along the length of breech 18, since an annular shoulder on bolt 23 will engage the energy buffer assembly 20. Bolt 23 (and hence projectile 11) remains captive after being fired.

A radially extending circular flange 29 extends from the exterior of muzzle 19 at a position towards its breech end. Positioned on said 6 flange 29 are two eye-bolts 30 set at 180' to each other and at 90' to the plane of arms 25. The eye-bolt illustrated in Figure 1 is to show its orientation and not its position, since it would in this section be hidden behind the muzzle 19. The eye-bolts 3 0 are such that 'D' shackles and wire cables or rods can be attached to them. At their other ends the cables or rods can be attached to winches or robust mountings on vehicles.

In Figure 2, for the sake of clarity only the arms 25 of projectile 11 are seen and the gun 10 is omitted.

When the gun 10 is fired by operating trigger 17, the arms 25 and the forward part of bolt 23 are driven through the window or screen 12. If this is done adjacent to a corner of the window frame 13 (see Figure 2), creating an opening 3 1, the gun can be then rotated through an angle of 30' or 45' to locate arms 25 with the spikes 27 on the inside of the window frame 13. By means of a cable attached to eye-bolts 30 at one end and a vehicle at the other. the window frame 13 surrounding window 12 can be pulled out. Two or more devices according to the invention can be used simultaneously or consecutively to create larger openings in windows or to pull out a window with its frame.

7

Claims

CLAIMS: 1. A device for penetrating a screen and permitting partial or

full removal of said screen or a surround enclosing said screen, the device comprising projection means adapted to receive a captive projectile, said projectile having means for penetrating said screen when the projectile is launched from said projection means in a position adjacent said screen, the projectile further having laterally extending location means adapted to be positioned behind still-extending portions of said screen or the screen surround following penetration, such that withdrawal of the captive projectile and/or its projection means may act to remove all or part of said still-extending screen or said screen surround.

Amendments to the claims have been filed as follows 1. A device for penetrating a screen and permitting partial or full removal of said screen or a surround enclosing said screen, the device comprising projection means adapted to receive a captive projectile, said projectile having means for penetrating said screen when the projectile is launched from said projection means in a position adjacent said screen, the projectile further having laterally extending location means adapted to be positioned behind still-extending portions of said screen or the screen surround following penetration, such that withdrawal of the captive projectile and/or its projection means may act to remove all or part of said still-extending screen or said screen surround. 2. A device as claimed in claim I in which the projection means has a muzzle from which said projectile can be launched, which muzzle is adapted in use to be located on or adjacent to the screen, the projection means and/or the projectile being adapted to ensure that the penetrating portion of the projectile is spaced from the screen prior to the actuation of the device. 3. A device as claimed in claim I or claim 2 in which the projectile extends longitudinally within the projection means and the projection means and/or the projectile is/are adapted to ensure that the projectile does not rotate about such longitudinal axis relative to the projection means. 4. A device as claimed in any preceding claim in which the penetrating and locating features of the projectile are provided by a T- shaped projectile or bolt, the leading or front edge of the projectile being 7.

adapted to perform the penetration function, with the arms of the T performing the locating functions after penetration of the screen. 5. A device as claimed in claim 4 in which the arms have spikes or similar projections on their reverse sides adapted to engage the reverse side of a screen or screen surround after penetration of the screen and subsequent rotation of the projection means. 6. A device as claimed in any preceding claim in which the projection means incorporates attachment means which enables a cable or a bar to be attached to the projection means.

A device as claimed in any preceding claim including means enabling the projectile to develop free flight before striking the screen. 8. A device as claimed in claim 7 when dependent upon claim 4 in which the muzzle is partially cut away at its exit end such that the arms of the T-shaped portion of the projectile extend substantially parallel to the plane of such a cut, the leading edge of the projectile being maintained a predetermined distance from the exit end of the muzzle. 9. A device as claimed in claim 1 in which the projectile is propelled by explosive means located in a chamber forming part of the projection means.

10. A device for penetrating a screen and permitting partial or full removal of said screen or a surround enclosing said screen, substantially as hereinbefore described with reference to the accompanying drawings.