GB2423270A - Device for breaking glass - Google Patents

Abstract

A device for breaking glass that may be attached directly to the glass and operated remotely to break said glass is described. The device has an assembly that, in function, charges, stores and releases energy, and transfers said energy to a tip, held in adjustable and self correcting contact with the glass surface. In use, a trigger pawl 1 is actuated and subsequently rotates a firing pawl 11 which charges energy to an extension spring 21. At a given point during the actuation process, the pawls 1 and 11 become disengaged, returning to their respective start positions. The energy stored in the extension spring 21 is transferred to the glass surface via an impacting shaft 21, a tip holder 25, and finally a diamond point 23. If the glass initially fails to shatter then the device may be repeatedly fired without returning to it.

Description

* 2423270 Window breaking device This invention relates to a window

breaking device that is loaded and fired with a single action, which is carried out remotely from the invention. It is significant in that it may be used to break windows with an operator at a safe distance.

During high risk search activities (for example, searching for terrorist improvised explosive devices, herein after called an lED'), or indeed any activity which encompasses entry into a tactically dangerous area, it is often necessary to enter an area by breaking windows. The process of breaking a window may lead to the detonation of an lED. For this reason there is a need to break windows remotely, where the operator is at a safe distance. Existing methods include using spring loaded impacting shafts, explosives or remote operated vehicles (herein after called ROY). Existing spring loaded devices have operational weaknesses in that they require preloading with energy before placing in position, and the use of safety catches which must be moved from a safe' position to a ready to fire' position before the extraction of the operator. They are intrinsically unsafe. They may also only be fired once, and need an operator to return if subsequent attempts are required to break the same window. Explosives may lead to forensic contamination, require skilled explosive operators, time to set up and other numerous disadvantages. ROY are often not available, and can take considerable time to deploy. There are often terrain issues that make the use of ROV difficult.

To break windows remotely, the present invention may be attached to a glass surface, and by the remote actuation of a trigger, will both load energy into an impacting shaft, and release the stored energy in the shaft, transferring the energy to a point made of an hard material. The point, which is pressed against the glass surface, generates high pressure at the tip, and thus shatters the glass. The remote activation will not only both load and release the impacting shaft in one operation, but will also urge the point constantly against the glass surface, ensuring maximum force is transferred from the impacting shaft to the point, and thus to the glass.

The invention may also be repeatedly fired, without returning to it, should the window fail to shatter on the first attempt. The actuation process loads energy into the impacting shaft, releases the stored energy in the impacting shaft, constantly urges the point against the glass and returns the invention back to the start point in a single action.

An example of the invention will now be described in detail, by referring to the accompanying drawings.

Figure 1 is a plan view of one version of the invention, showing the main body with the firing paw!, trigger paw!, torsion spring, return extension spring, impacting rod, firing spring, tip holder and tip. The shoulder retaining bolts and cover plate are not shown.

Figure 2 is a plan view from the opposite side to figure 1 of the assembly, with the cover plate removed.

Figure 3 is a top view of the impacting shaft.

Figure 4 is a plan view of the tip holder.

Figure 5 is a bottom view of the main body only, showing the slot in which the trigger pawl moves.

Figure 6 shows the actuation mechanism starting to load the firing mechanism.

Figure 7 shows the actuation mechanism approximately half way though loading the firing mechanism.

Figure 8 shows the actuation mechanism about to release the firing mechanism.

Figure 9 shows the actuation mechanism part way though the automatic return process.

Figure 10 shows the actuation mechanism part way though the automatic return process shortly after the stage shown in figure 9.

The device offers the ability to break glass windows without the operator being in the vicinity.

The device is reusable, does not have any disposable parts, and as such has no components which must be replaced after each use, or any other given time frame.

The device may be set up very quickly. No pre checking, arming or safety mechanisms or other processes for storing energy are required whilst the operator is setting up the device, or is in its vicinity.

The loading and firing operation is completed in one remote action, after the operator has positioned the invention in place and retired to a safe location. After the firing operation is complete, the invention returns itself to the start position, and the invention may be fired again without returning to it if it is still attached to the glass. This process may be carried out indefinitely if it is still attached to the glass. Other window breakers have been designed for this purpose, but these require preloading with energy, and thus need safety catches. They may also only be fired once.

It is known that a point held against toughened window glass panes, which is then struck by suitable force, will shatter the glass. In order to achieve maximum pressure at the tip, it is essential that the tip is held in firm contact with the glass surface. Furthermore, if the point is of a suitable material, this process may be repeated many times before the point becomes so blunt, that the pressure generated at the surface is insufficient to shatter the window. If the point is made of a material such as diamond, the point will last almost indefinitely.

The use of rubber suction pads to attach tools to glass is well known, however the rubber cups used are not made to exacting dimensions, and it is difficult to get very accurate positioning. Also, during activation of a window breaking device, when a load is applied (e.g. by a rope or solenoid) during the firing sequence, some deflection of the rubber cup occurs, moving the point away from the glass. Finally, glass window panes are made in a range of curvatures (including flat). These 3 variables thus make it extremely difficult to predict the position of the tip, in relationship to the glass surface.

This invention has a mechanism that during loading and firing, also constantly urges the point against the glass so that it is in permanent firm contact with the glass surface. The point is a diamond, the hardest material known to man. This ensures the point will not shatter or wear out.

The window breaking device consists of 2 main parts. The main body assembly which houses the firing mechanism (shown in figure 1), and the mount assembly (shown in figure 2), which attaches the main body assembly to the suction pad, and allows it to move in such a way as to constantly urge the point against the glass during activation.

The main body sub assembly shown in figure 1 comprises a trigger pawl 1, preferably made from hardened stainless steel which pivots around a point 2 in the main body 5, and is retained by virtue of a shoulder bolt. It has a ring 3 at one end which may be attached to a line or other actuation device. The trigger paw! 1 has an elongated slot 4 which allows the trigger paw! to rotate around the pivot 2 on the main body 5, and also move longtiduitionally on the pivot 2. On the left side of the trigger paw! 1 is a lobe with an upper engaging face 6. On the right side is an attachment point 7 for an extension spring 8. A small groove runs partially around the circumference on the round section, into which nests the torsion spring 38.

The extension return spring 8 is attached to the trigger paw! 1 at a point 7, routed around a screw or bolt 9 and attached at another screw or bolt 10 in the main body 5, biasing the trigger paw! 1 to move to the ready to fire' or home' position. This position is indicated in figure 1.

The torsion spring 38 urges the trigger paw! 1 to move to right hand side of the slot in the trigger paw! 1.

A firing paw! 11, preferably made from hardened stain!ess steel, pivots around a point 12 in the main body 5 and is retained by virtue of a shoulder bolt. On the right side of the firing paw! 11 is a lobe with a lower engaging face 13. This lower lobe face 13 engages with the upper lobe face 6 on the trigger paw! 1. At the top end of the firing pawl 11 is a pin 14, which moves in a circular arc, when the firing paw! 11 rotates around the pivot 12.

2 shoulder bolts act as pivot pins and retain the trigger pawl 1 and firing paw! 11 in threaded holes on the main body 5.

An impacting shaft 17, preferably made from hardened stainless steel, has a slot 18 (shown in figure 3) which engages with the pin 14 of the firing paw! 11. The impacting shaft 17 passes though a hole at the rear of the main body 5 which checks the movement and ensures it moves in a longitudinal path. The impacting shaft 17 has a groove 20 (shown in figure 3) around its circumference about 2/3 the way along its length, to which a firing spring 21 is attached.

The firing spring 21 is attached to the front part of the impacting shaft 17 by way of the groove 20 in the impacting rod. The other end is attached to a tip holder 25 by a similar groove 22 in the tip holder 25. (Shown in figure 4) The tip holder 25, designed to hold a replaceable tip 23, has a groove 22 (shown in figure 4) around its circumference at one end to engage with the firing spring 21. The tip holder 25 has a larger diameter than the mounting hole in the main body 5, so that when inserted into the front of the main body 5 and attached to the firing spring 21, the tip holder 25 is held in place.

A replaceable tip 23, that contains a hardened material (e.g. diamond), suitable for breaking glass is inserted, and held, by way of thread, grub screw or taper fit, into the tip holder 25.

A cover plate covers the internal working of the main body sub assembly.

The main body 5 is preferably made from high strength aluminium which has been anodised. It has attachment points 2 & 12, which are threaded holes for 2 shoulder bolts that act as pivots pins. It has a 3I threaded hole 26 which acts as an anchor for the torsion spring 38. It has a 4th threaded hole 10 which acts as the anchor point for the return extension spring 8. It has a 5th threaded hole 9 which accepts a standard screw or bolt, around which the return extension spring 8 is routed. It has a hole in the back to allow the rear section of the impacting shaft 17 to pass freely in. It has a stepped hole at the front, into which the tip holder 25 sits freely, and the firing spring 21 may pass though freely. The stepped hole only allows the tip holder 25 to be inserted from the outside face.

The main body 5 has a boss 28 which arrests movement of the firing pawl 11 in the forward (clockwise direction).

It has a slot 29 in the bottom face (shown in figure 5), through which the trigger paw! I may pass freely.

It has a hole 27 in the back face though which a pivot 33 to the mount 30 passes.

It has a 2' hole in the back face 31, towards the front, into which a screw 32 passes though and into the mount 30. It has threaded holes on the surface, onto which a cover plate may be attached.

The mounting assembly (shown in figure 2) constitutes the mount 30, preferably made from high strength aluminium, which consists of a mounting point 34 to attach it to a suction cup 35, or other suitable device used for attachment to glass.

The mount 30 has a pivot 33 which allows the main body sub assembly to rotate about said pivot 33. A circular slot 36 restricts the rotation of the main body sub assembly to a suitable range.

A ring 37 is attached to the mount 30, which allows a short rope to be attached to the side. Should it be required, the other end of this short rope may then anchored elsewhere than from the glass. In use, after the window has been shattered, the invention will hang from the short piece of rope, reducing any post shattering damage occurring to the invention by its impact with other objects as it falls. The rope may also be useful for stopping the invention locating itself in an inappropriate area.

A cover plate covers the internal working of the mount.

The device is attached to the glass by way of a rubber suction cup 35, or any other Suitable method for attachment to glass. No preloading is required, and there are no safety switches or mechanisms that need to be set.

A line or other suitable method for applying force to the invention is then attached to the ring 3 on the trigger pawl 1.

As a force is applied to the ring 3 on the trigger pawl 1, the main body assembly 42 rotates about the pivot 33 in the mount 30. This rotation continues, until the tip 23 comes in contact with the glass. At this stage, rotation of the main body assembly 42 is checked, and the trigger pawl I begins to rotate around the pivot point 2, whilst the torsion spring 38 urges the trigger pawl 1 to the right hand side of the elongated slot 4.

As the trigger paw! 1 continues to rotate around the pivot 2, the upper engaging face of the lobe 6 on the trigger pawl 1 impinges on the lower engaging face of the lobe 13 on the firing pawl 11. (See figure 6) The firing paw! 11 subsequently rotates anti clockwise around the pivot point 12.

Any deflection or deformation of the rubber suction cup 35 (or other method of attachment to glass) that occurs, results in continuous further incremental rotation of the main body around the pivot 33 in the mount 30, ensuring the tip 23 stays in constant contact with the glass.

The pin 14 on the firing pawl 11 is engaged with the slot 18 on the impacting shaft 17. The arc generated by the pin 14 on the firing pawl 11, as said firing paw! 11 rotates anti clockwise, is sufficient that it will move the impacting shaft 17 longitudinally rearwards. The impacting shaft 17 passes though a hole in the rear of the main body 5 to ensure movement is checked into a linear direction.

As the impacting shaft 17 is attached to the rear of the firing spring 21, and the firing spring 21 is anchored at the front via a groove 22 in the tip holder 21, the firing spring 21 extends. As the firing spring 21 continues to extend, it urges the firing pawl 11 to rotate clockwise about the pivot point 12, but this movement is restricted as the bottom engaging face of the lobe 13 on the firing paw! 11 is in contact with the top face of the engaging lobe 6 of the trigger paw! 1. The firing spring 21 is therefore loaded with energy.

As the trigger pawl 1 rotates, a point on the top face of its engaging lobe 6 moves along a point on the bottom face of the engaging lobe 13 on the firing paw! 11.

(Figure 7) At a given point during rotation of the trigger paw! 1 (approximately degrees from the start position) the engaging faces of the firing & trigger paw! lobes 6 and 13 are no longer in contact, (figure 8) and the firing spring 21 is now able to rotate the firing paw! 11 clockwise.

The energy thus accumulated in the firing spring 21 is released, moving the contact face 39 of the impacting shaft 17 longitudinally forward. The accumulated energy of the firing spring 21 is transferred to the impacting shaft 17, which upon returning to its home position, transfers this force by way of impaction to the tip holder 25.

The replaceable tip 23 is held within the tip holder 25. The energy transferred to the tip holder 25 is subsequently transferred to the tip 23 itself, and finally to the glass. The small surface area of the tip 23 ensures the pressure generated is significant enough to shatter the glass. The device is now fired'.

The firing pawl 11 meanwhile, by way of its pin 4 being engaged into the slot 18 of the impacting shaft 17 has also returned to its home position. Its rotation clockwise is arrested by the side of the firing pawl 11 coming to rest on the edge of the boss 28 in the main body 5.

After firing, the trigger paw! 1, is still in the rearwards firing position, and will remain so until the method of actuation is released. When the method of actuation is fully released, the return extension spring 8 will gently urge the trigger paw! 1 anti clockwise back to its home position. During the return - 10- rotation of the trigger pawl 1, the bottom face of its engaging lobe 40 will impinge on the top face 41 of the firing pawl 11 engaging lobe (figure 9). At this point, the force applied to the trigger pawl 1 by way of the return extension spring 8 will move the trigger pawl 1 forward on the pivot point 2 (figure 10).

The trigger paw! 1 has an elongated slot 6 in it, allowing both rotation, and some longitudinal movement around the pivot point 2.

Once the trigger pawl 1 has moved forward (to the right) on the pivot point 2, the upper 41 and lower 40 engaging faces on the firing paw! 11 and trigger paw! 1 lobes respectively will no longer impinge, and the trigger pawl 1 will be allowed to continue on its journey back to its home position.

Once past the area of impingement, the torsion spring 38 will urge the trigger pawl 1 rearwards (to the left) along the pivot point 2, ensuring that when fired again, the engaging lobe faces 6 and 13 will meet correctly.

Should the window fail to shatter, the process may be repeated indefinitely, as the device automatically loads, fires and returns to the pre fire (start) position with a single actuation on the trigger pawl 1.

Claims (13)

1. A device for breaking glass having an assembly which may be fixed to a glass surface, which in function both charges, stores and releases energy, transferring said energy to a tip that is held in constantly adjustable and self correcting, contact with the glass surface by virtue of the same process that charges the device with energy.

2. A device as claimed in Claim 1 wherein the process of charging, storing and releasing energy may be repeated without returning to the device, if it remains attached to the glass surface.

3. A device as claimed in Claim 1 wherein the diamond point is constantly urged to press against the glass surface.

4. A device as claimed in Claim 3 where a pivot allows the tip to rotate, constantly urging it against the glass surface.

5. A device as claimed in Claim 1 wherein a rotating pawl, having an engaging lobe, engages with a lobe on another rotating pawl, which by virtue of the other pawl's length creates a moment arm significant enough to charge energy into an extension spring.

6. A device as claimed in Claim 5 wherein at a given rotation, the engaging lobes of the rotating pawls cease to be engaged.

7. A device as claimed in Claim 5 wherein the 2 pawls automatically return to their start position after enough energy to break the glass has been transferred to an extension spring.

8. A device as claimed in Claim 6 wherein the 2 pawis automatically return to their start position after the lobes on the pawis have ceased to he in contact.

9. A device as claimed in Claim 5 wherein the stored energy in the extension spring is transferred to a moveable impacting shaft.

10. A device as claimed in Claim 9 wherein the impacting shaft transfers its energy to a fixed tip holder.

- 12 -

11. A device as claimed in Claim 10 wherein the fixed tip holder transfers its energy to a diamond point.

12. A device as claimed in Claim 11 wherein the energy transferred to the tip generates enough pressure to shatter the glass.

13. A device as claimed in Claims 1, 3, 4, 11, 12 wherein the tip is made from diamond.