GB2290821A - Security grating assembly - Google Patents

Abstract

The present invention relates to a security grating assembly comprising a plurality of bars 1 and a mounting arranged to receive the bars at a plurality of positions for locking them into selectable positions. An opposed mounting 3 is arranged to receive the ends of the bars 1 not locked into the first mounting. The bars 1 may have a core which rotates relative to a sleeve when the sleeve is cut through by a saw or the like. The bars 1 are inserted through holes 29 in a plate 22 arranged in the mounting such that slots 14 are level with the plate 22. The plate 22 is then moved and locked in a position where the rims of the holes retain bars 1. One or more strengthening struts can be attached across a plurality of the bars. <IMAGE>

Description

SECURITY GRATING ASSEMBLY The present invention relates to a security device. In particular, it relates to an improved grating for mounting in window or other opening.

Bars and gratings have long been used as a means of securing windows against entry. In modern society, awareness of crime has increased and thus there is a desire to use grating to protect people, homes and other premises against intruders.

Clearly such gratings should be as secure as possible; their bars may be permanently mounted across a window, perhaps set into the surrounding frame and wall. However, there is a conflict because the requirements for positioning or presence of the bars may vary. In an emergency, such as a fire, the window might be the only exit which is safe to use. Equally people may simply dislike being in a room with bars across the window. To solve this dilemma, various types of sliding shutters are known but these tend to be more cumbersome, unsightly and costly than bars.

According to one aspect of the present invention there is provided a security grating assembly comprising a plurality of bars and two mounting in use arranged opposing one another, each mounting comprising a casing having a plurality of holes into which the ends of the bars may be selectively inserted, at least one mounting having means for lockably retaining bars inserted into respective holes in the casing, wherein the casings of the two mountings have substantially the same cross-section and one of the mountings is provided with a limiting member for limiting the depth of insertion of the bars there into.

The present invention can facilitate positioning of the bars in the mounting and can also reduce manufacturing costs by allowing both casings to be produced in the same way.

In order that the invention may be more fully understood the following description is given, merely by way of example with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a first embodiment of the grating assembly; Figure 2 is a lateral cross-sectional view of the casings of the first embodiment; Figure 3 is a longitudinal cross-sectional view of the first embodiment, Figure 4 is a cut-away perspective view showing the internal structure of the bars; Figure 5 is a perspective view of a second embodiment; Figure 6 is a horizontal cross-sectional view of the second embodiment, Figure 7 is an exploded perspective view illustrating a possible driving mechanism for the plates; Figure 8 shows an alternative plate driving and locking mechanism;; Figure 9A-C, Figures 1OA-B and Figure 11 show respective strengthening struts which may be used with the grating assembly of the present invention; Figure 12 shows a perspective view of a third embodiment of the present invention; Figure 13 shows a cross sectional view of the mounting of Figure 12, Figure 14 shows a cross sectional view of a fourth embodiment.

The first embodiment, shown in Figure 1, has two mountings 2 and 3 which have identical rectangular, hollow metal outer castings 21 formed by extrusion with a cross-section as shown in Figure 2. Each casing 21 has an array of circular holes 24, equally spaced on one side along the length of the respective casing 21.

In use, mountings 2 and 3 are arranged with the holes 24 of each casing 21 opposed to each other above and below, or left and right, a window such that the bars 1 may be positioned across the window by inserting the ends of the bars in the corresponding holes 24 of each mounting 2 and 3. Thus holes 24 may be slightly larger than necessary to accommodate the bars 1 so that it is possible to angle the bars 1 into place whilst holding them in the top section deeper than when in the locked position.

For fitting casing 21 to a window frame, there is drilled along the length of each casing 21 an array of holes 31 for insertion of screws 32. For convenience of mounting of the casing 21 and for additional security, these holes 31 are positioned directly opposite the bar holes 24.

The structure of the bars 1 may be seen from Figures 4A and 4B. The bars 1 have a core 11 made of hardened steel covered by an outer sleeve (or jacket) 12 which is made of mild steel and has an outer layer 13 of aluminum which may be anodised or painted, or may be separate from sleeve 12. The sleeve 12 may alternatively be painted, or decorated by structural features attached thereto. The core 11 is free to rotate relative to the sleeve 12 so that if the sleeve 12 is cut through by a saw, the saw teeth tend merely to rotate the core 11 rather than biting into it.

When the bar 1 is fitted in the mounting 2 and 3, the sleeve 12 completely covers the core 11 between the two mountings 2 and 3, so that the core 11 is not exposed and may accordingly not be gripped to prevent this rotation. To prevent the core 11 being gripped by clamping the outside of the sleeve 12, the sleeve 12 may be made relatively thick or the dimensions of the core 11 and sleeve 12 may be chosen such that there is a gap between them.

In general terms, the sleeve 12 may have any configuration provided it has a bore large enough to accommodate the core 11, though the simple tubular arrangement of the sleeve 12 used in this embodiment is particularly cheap and simple to construct.

It would also be possible to provide a more complicated system of bars 1 with the various sleeves 12 linked together eg. by laterally extending links.

For the purpose of locking the bars in place, in the ends, the bars 1 are formed with a circumferential slot 14 perpendicular to the axis of the bars 1 and a plate 22 facing the holes 24 is provided in the mounting 2. The slot 14 in one end is formed in the main body of sleeve 12. The slot 14 in the other end of bar 1 is formed between the main body of sleeve 12 and the head of a cap nail 17, the shaft 17a of which is fixed in the bore of sleeve 12 in which core 11 is accommodated.

A series of key-shaped or keyhole-shaped holes 29, i.e.

holes which are larger at one end than the other, are arranged along the length of plate 22 with the same spacing as the holes 24 along mounting 2, and plate 22 is slidable along the length of the mounting 2, resting on two opposed ledges 27.

The wider ends of key-shaped holes 29 in plate 22 are big enough for the portion of the bar 1 below the slots 14 to pass vertically through, whereas the narrower ends of key-shaped holes 29 are not.

The vertical position of the plate 22 is chosen in conjunction with the position of the slot 14 in the bars 1 such that when bars 1 are inserted into the holes 24 of mounting 2, the plate 22 is at the level of the hole slots 14.

To insert the bars 1, the plate 22 is moved to align the wider end of each key-shaped hole 29 with the centre of a bar hole 24 of mounting 2. One end of each bar 1 is inserted at a slight angle into mounting 3 through a hole 24. Then, the other end of each bar 1 is positioned over a hole 24 of mounting 2 and inserted through that hole 24 and also through the corresponding hole 29 of plate 22 to align slot 14 with plate 22, at the vertical level shown in Figure 3.

In mounting 2, a plate 28 resting on ledges 29 prevents bars 1 from being inserted into the full depth of mounting 2.

This arrangement allows the casings 21 of each mounting 2 and 3 to be identical, because the end of each bar 1, inserted first into mounting 3 passes the level of the ledges 29, which bear no plate in mounting 3, to provide clearance for the other end over mounting 2. Without plate 28, mounting 2 would need to be left deep enough to prevent the end of each bar 1 inserted in mounting 3 coming out of mounting 3 when the other end of each bar 1 is moved into mounting 2.

To retain bars 1 in place, plate 22 is moved from the position shown in Figure 3 along mounting 2 to move the narrower ends of key-shaped hole 29 into slots 14 of bars 1, whereat the rims of the narrower ends of key-shaped holes 29 catch against the respective radially extending inner surfaces of slots 14 to prevent bars 1 from being moved. Plate 22 is then locked into this position to prevent bars 1 from being removed until plate 22 is unlocked and moved back to its original position.

Though it is not necessary to have slots 14 at both ends of the bar, this allows bars 1 to be inserted either way up, and hinders forced removal of the bars 1 by distortion from casing 3 by means of the slot 14 catching on the rim of hole 24 in casing 3. It is possible to select which holes (ie. which positions along the length of mountings 2 and 3) are to receive bars. Fittings may be provided to fill holes 24 in which bars 1 are not arranged.

The corner of each casing 21 is formed with a cylindrical channel 25. Optionally, each channel 25, or at least the channels 25 at the corners exposed in use, may accommodate a rotatable, hardened steel, cylindrical core 26 extending along the entire length of casing 21. By virtue of being rotatable, cores 26 act as a security measure against someone sawing into casing 21 which may otherwise be the weakest part of the grating.

The second embodiment shown in Fig. 5 is similar to the first embodiment, uses the same bars, and is formed with bar holes 124 and fitting holes 131 for the same purpose as holes 24 and 31, respectively, of the first embodiment.

The track of plate 122 is defined by pairs of lug 123 arranged above and below plates 22 on opposite sides of casing 21. Alternatively, to define the track, ribs along the length of the mounting could be used or else the plate could be formed with flanges extending perpendicularly to plates 122 across the hollow casing 121. A plate 122 with such flanges can be Ishaped such that the plate would be held in the middle of the casing 121, or can be U-shaped such that the plate 122 is adjacent to the surface of the casing 121 which has the holes 124. In the second embodiment, plate 122 has a series of circular holes 129 which are larger than the portion of bar 1 below slots 14.When the plate 122 is moved along mounting 102 to the position shown in Figure 6 by the dotted circle 129' where the rim of holes 129 on one side have been slid into respective slots 14 of bars 1 to act as catches against respective readily extending inner surfaces of slots 14.

An alternative is to use a hole of a type similar to the keyhole-shaped holes 29 of the first embodiment.

A further alternative arrangement is to use a pair of parallel plates 122a and 122b similar to plates 122 as in Figure 7. For inserting bars 1, the pair of plates are aligned such that the centres of their holes 129 are concentric and aligned with bar holes 124 of mounting 102. The plates 122a and 122b are movable in opposite directions, to the respective positions shown by the dotted circles 129' and 129" shown in Figure 6, at which positions they are lockable and the bars 1 are held co-operatively by the plates 122a and 122b on opposite sides of the slot 14.

Alternatively, the mounting 102 could be constructed with the plate 122 adjacent to the surface of outer casing 121 having the holes 24, such that, to hold a bar 1 in place, the plate 122 enters its slot 14 and pushes the bar 1 across such that the rim of hole 124 of mounting 102 entering the opposite side of slot 14.

The arrangement of the first and second embodiments are particularly advantageous because all the components of the grating assembly can be manufactured in any size and later cut down to fit a window of particular dimensions. This makes the manufacture of the grating assemblies cheaper and more efficient by allowing batches of the same size to be made. It also allows the grating assembly to be sold as a pack which the buyer is to fit. The plate 22, 122 and the casing 21, 121 may both simply be cut down to size, before mounting. If separate, the outer layer 13 may similarly be cut to fit. The sleeve 12 being preformed with the slot 14 at one end, may be also cut to fit at the other end, as may be the core 11, prior to being inserted inside sleeve 12. Thereafter, cap nail 17 is inserted to form the slot 14 between the cut end of the sleeve 12 and the head of the cap 17.

As an alternative, it would be possible for the cores 11 to extend out of the sleeve and for the slots to be formed in the core, though it would be desirable to ensure the sleeve were long enough to extend into the mounting to protect the core against being clamped.

A strengthening strut is shown in Figure 9. It is formed of two portions 53 and 54 of generally U-shaped cross section, portion 53 being of such a size that portion 54 may be slipped inside. Portions 53 and 54 are adapted to be firmly fixed together, for example by the screws (not shown), and each have opposing recesses 55 at the same spacing as the bars 1 to receive bars 1 when portions 53 and 54 have been fixed together.

Collars 50, as shown in perspective in Figure 9B, are clamped on desired bars at the same height, for example as shown in Figure 9A. The portions 53 and 54 are then brought together from either side of bars 1 and secured together over collars 50, for example at the position shown by dotted line 51 in Figure 9A. Once the strut shown in Figure 9 has been secured, bars 1 on which a collar 50 has been clamped may not be removed because collar 50 is too big to fit through the recesses 55. Bars 1 without a collar attached may slip through the strengthening strut without difficulty.

A top view of another strengthening strut 57 is shown in Figure l0A and comprises two planar portions 58 and 59 which are held together edge-to-edge by screw 60 extending therebetween. Portions 58 and 59 have recesses in positions to accommodate bars so that strut 57 may be arranged around the bars as shown in perspective in Figure 8B. That is to say, portion 58 has a series of semi-circular recesses 61 with the same spacing as the bars. Portion 59 has, at positions opposite some of the recesses 61, semi-circular recesses 62, thereby forming circular apertures 64 for accommodating bars 1 when portions 58 and 59 are screwed together. In Figure l0A such an aperture 64 is formed at the end position.

At the positions corresponding to the other recesses 61 of portion 58, portion 59 has a deeper recess 63 which is as wide as the bars 1 are thick. In the Figure 10 strut, recess 63 also extends between the position of adjacent bars 1. Thus, when strut 57 is secured, it prevents the bars 1 in apertures 64 from being removed, but the bars opposite the deeper recess 63 are provided with sufficient space to be angled out of the grating assembly. The deeper recess 63 extends between adjacent recesses 61, thereby allowing bars 1 to be slid along strut 57 for use, for example, with the third embodiment described below.

Alternatively the struts may be configured as a series of separate flat strut sections 47 interlinked by a dovetail joint 49 as shown in Fig. 11. This configuration simplifies manufacture, because identical sections 47, with one, two or more bar-locating holes 48 and with the male and female halves of the joint at opposite ends, may be produced and subsequently joined together for a strut of any desired length.

The struts shown in Figures 9, 10 and 11 are optional, but when secured they strengthen the bars against forceable distortion, whilst still allowing the removal of particular bars, for example if sufficient bars need to be removed to allow exit in an emergency. In addition, if the struts are secured tightly to the bars 1, then they will prevent rotation of the sleeves 12, making it harder to saw therethrough.

The arrangements for moving and locking plates 22 of the first and second embodiments are described next, though any arrangement could easily be used in any other embodiment.

In the first embodiment, as shown in Figure 3, plate 22 is moved simply by a knob 90 with a shaft 91 inserted in plate 22, shaft 91 being movable along the length of mounting 2 in a slot 92 in casing 21.

To lock plate 22 in position to retain bars 1 a lock mechanism 93, of a type which is known per se, is provided in mounting 21. Mechanism 93 is key-operated to lock a bolt 94 into a hole 95 formed in a U-shaped portion 96 of plate 22 extending around mechanism 93, thereby to prevent plate 22 from being moved back to a position where bars 1 may be removed.

An alternative arrangement (not shown) is for plate 22 to have two separated holes 95, one hole 95a located in plate 22 to align with bolt 94 when plate 22 is in the bar-retaining position and the other hole 95b located in plate 22 to align with bolt 94 when plate 22 is in the open position where the bars may be removed. In this way, locking mechanism 93 may be used not only to lock plate 22 into position for retaining bars 1, but may also be used to lock plate 22 in the open position.

This is advantageous in use, because it allows one to prevent the bars being accidentally locked in place at times when it may become necessary to remove bars 1, for example while the building is occupied1 and because the key need not be left in the mounting where it might be lost, stolen or duplicated.

A method of locking plate 22 which avoids the cost of mechanism 93 is to make knob 90 removable and to form plate 22 with a screw-hole 97 positioned adjacent knob 90 and aligned with slot 92 only when plate 22 has been moved from the position shown in Fig. 3 to the position for retaining bars 1.

Then knob 90 may be removed, allowing a security screw to be inserted in screw hole 97 to prevent plates 22 from being moved back. Preferably, knob 90 is replaced so that its broad base conceals the security screw.

Figure 7 shows a first possible mechanism for driving plates 122 in the second embodiment with two such plates 122a and 122b. By stepping the plates, opposed, spaced apart portions 132a and 132b of the respective plates 122a and 122b are formed with a gap 129 therebetween. Across the width of each plate 122a and 122b, on the stepped portions 132a and 132b there is a series or elongate slots 127a and 127b. The slots 127 receive the teeth of a toothed cog 128 which is arranged in the gap 129 between the spaced apart portions 132a and 132b, the spacing between the slots 127 being chosen to match the spacing of the teeth of cog 128. The engagement of the teeth of cog 128 in the slot 127 causes the plates to move in opposite directions when the cog 28 is rotated.If the cog is moved in the direction of arrow C, plate 122a moves in the direction of arrow A and plate 122b moves in the direction of arrow B. The cog 128 is driven by a co-axial lever 125 (shown in Figure 5) which protrudes out of the casing 121 of mounting 102. Thus rotation of lever 125 causes plates 122a and 122b to move between their working positions.

To lock the lever 125 in the position where plates 122a and 122b retain the bars 1 in mounting 102, a simple barrel lock 126 is provided between the lever 125 and the mounting 102. There are many other possible structures known for such a lockable lever 125.

Although the mechanism shown in Figure 7 has two plates 122a and 122b, a similar arrangement may be used to drive a single plate 122 as is used in the embodiment shown in Figure 5 Instead of using a cog and a lever to drive the plate 22, an alternative mechanism is the separate unit 40 shown in Figure 8. This unit 40 comprises a cylinder block 42 movable between two limits (in the direction shown by arrows D) in a barrel 41. A pin 44 is connected to block 42 on a shaft 46 protruding out of the barrel 41. The end of the pin 44 is bevelled to created a cam surface 45.

To use the unit 40, once bars have been arranged in selected positions in the mounting 2, the unit 40 is arranged above an unused hole 24 with the pin 44 protruding into that hole 24, the barrel 41 being larger than the holes 24 so that it sits against the outer surface of mounting 2. By pushing the block 42 down into the barrel 41 the pin 44 is driven against the plate 22 and the action of the cam surface 45 against the rim of the hole 29 below causes the plate 22 to move into position for holding the bars 1 in place.

To lock the block 42 down, there is a locking mechanism between the barrel 41 and the block 42, which is operated by a key inserted in slot 43. The locking mechanism used is of a known type, such as that used in a known window lock of similar construction to unit 40.

The plate is preferably biased to return to a position where the bars 1 may be removed when unit 40 is unlocked and removed. A spring may be used for this purpose.

Alternatively a lever similar to that used in the first mechanism may be employed to move the plate 22, whilst using a unit similar to unit 40 to lock the plate 22 in place.

There are many other possible ways of holding the bars 1 in the mountings, for example, using the arrangement of the third or fourth embodiments, in which parts equivalent to parts in the first embodiment share the same reference numerals.

In the third embodiment shown in Figures 12 and 13, the bars 1 have a core 11 completely encased in sleeve 12, the sleeve 12 having at each end a flange 83 extending outwards radially from the sleeve.

The mounting 2 of the third embodiment comprises a base portion 65 along one edge of which a lockable hinged lid 81 is mounted hinged in a groove 64. Base portion 65 has two lips 66 and 67 forming therebetween a gap 68 over a cavity 69 for accommodating the flanges 83 of bars. Gap 68 is wider than the sleeves 12 but narrower than flange 83, so that the bars may be slid along base portion 65 but may not be pulled out through gap 68. At one end of the base portion 65 there is a slot 80 through lips 67 allowing a number of bars to be introduced into base portion 65 when lid 81 has been opened. Whilst lid 81 remains open, the bars 1 may be slid along to semi-circular recesses 70 in lips 66 of base portion 65 in which bars 1 sit.

At positions opposite recesses 70, lid 81 has recesses 71, whereby closing of lid 81 fixes bars 1 in place along mounting 2. Thus lid 81 may be locked shut by a known type of lock whereafter lips 66 and 67 act as catches against radially extending flange 83 to prevent the bars 1 being removed.

The fourth embodiment shown in Figure 14 uses mountings 2 and 3 having a case 21 similar to that of the second embodiment with holes 24 at positions along its length. The bars 1 are fixed in place by a floating plate 75 movable by a screw or screws 76 arranged along the length of mounting 2. In Figure 14, a screw 76 is shown to one side of the plate 75, both such screws 76 may be positioned anywhere on the plate, for example along the centre of the length of case 21. Plate 75 may thus be moved away from the holes 24 in mounting 2 so that a bar 1 can be inserted into the full depth of casing 21.

When bars 1 have been arranged in desired positions along mounting 2 and 3, plate 75 is screwed down towards the bars 1 to a position where plate 75 prevents bars 1 being withdrawn from the opposite mounting sufficiently far to enable removal of the bars. Screws 76 are security machine screws, for example of the type which requires a special key to allow the screw to be inserted or removed or of the non-removal type in which the sides of the slot are tapered to allow the screw to be screwed in but not unscrewed.

Because the slots 14 in the end bars 1 in mounting 2 and 3 are at a position inside holes 24 of mountings 2 and 3, in this embodiment the slots 14 make it difficult to bend the bars 1 out of mounting 2 and 3, because they catch on the rim of holes 24 if the bar is distorted.

Claims (21)

1. A security grating assembly comprising a plurality of bars and two mountings in use arranged opposing one another, each mounting comprising a casing having a plurality of holes into which the ends of the bars may be selectively inserted, at least one mounting having means for lockably retaining bars inserted into respective holes in the casing, wherein the casings of the two mountings have substantially the same cross-section and one of the mountings is provided with a limiting member for limiting the depth of insertion of the bars thereinto.

2. A security grating assembly according to claim 1, wherein said limiting member comprises one or more plates arranged across the casing of the first mounting below respective holes.

3. A security grating assembly according to claim 2, wherein said limiting member comprises a single plate extending along the casing of the first mounting.

4. A security grating assembly according to claim 2 or 3, wherein the plate or plates of said limiting member is supported on opposed ledges formed internally in said casing.

5. A security grating assembly according to any one of the preceding claims, wherein said retaining means comprises a movable plate with an array of holes arranged in positions corresponding to the holes in the casing of the first mounting, the plate being movable, from a first position where the ends of the bars are insertable through both the casing holes and holes in the movable plate, to a second position where the rims of the holes in the movable plate engage and retain the bars inserted in the first mounting and whereat the plate is lockable.

6. A security grating assembly according to claim 5, wherein the rims of the holes of the movable plate engage inner surfaces of slots formed in the bars, when the movable plate is at said second position.

7. A security grating assembly according to claim 5 or 6, wherein said retaining means comprises two movable plates which are reciprocally movable and the rims of corresponding holes co-operatively engage opposite sides of the bars.

8. A security grating assembly according to any one of claims 5 to 7, wherein the movable plate or plates is or are moveable by engagement with a toothed cog connected to a lever which protrudes from the mounting and is lockable in a position corresponding to the locked position of the movable plate or plates.

9. A security grating assembly according to any one of the claims 5 to 8, wherein said movable plate or plates is or are lockable at said first position

10. A security grating assembly according to any one of claims 5 to 9, wherein said movable plate or plates is or are supported by opposed ledges formed internally in said casing.

11. A security grating assembly according to any one of the preceding claims, wherein the bars have a sleeve and a core, the sleeve and the core of each bar being relatively rotatable.

12. A security grating assembly according to any one of preceding claims, wherein the casing of either or both mountings includes at least one rotable core extending lengthwise along the mounting.

13. A security grating assembly according to any one of the preceding claims, further comprising one or more strengthening struts attachable across a plurality of bars.

14. A security grating assembly according to claim 13, wherein said one or more struts comprise a member with a plurality of holes for accommodating the bars.

15. A security grating assembly to claim 13, wherein said one or more struts comprise a series of members linked together by dove-tail joints, each member having one or more holes for accommodating the bars.

16. A security grating assembly, comprising a plurality of bars and two mountings in use opposing one another, each mounting comprising a casing having a plurality of holes into which the ends of the bars may be selectively inserted, the first mounting having means for retaining bars inserted into respective holes in the casing, wherein the assembly further comprises one or more strengthening struts attachable across a plurality of bars.

17. A security grating assembly according to claim 16, wherein said one or more struts comprise a member with a plurality of holes for accommodating the bars.

18. A security grating assembly according to claim 16, wherein said one or more struts comprise a series of members linked together by dove-tail joints, each member having one or more holes for accommodating the bars.

19. A security grating assembly comprising a plurality of bars and two mountings in use opposing one another, each mounting comprising a casing have a plurality of holes into which the ends of the bars may be selectively inserted, the first mounting having a movable plate with an array of holes, arranged in positions corresponding to the holes in the casing of the first mounting, the plate being movable, from a first position where the ends of the bars are insertable through the casing holes and holes in the plate, to a second position where the rims of the holes in the plate engage and retain the bars inserted in the first mounting to retain them and whereat the plate is lockable, wherein the plate is also lockable at said first position.

20. A security grating assembly comprising a plurality of bars and two mountings in use arranged opposing one another, each mounting comprising a casing having a plurality of holes into which the ends of the bars may be selectively inserted, the first mounting having means for lockably retaining bars inserted into respective holes in the casing, wherein the casing of either or both mountings includes at least one rotatable core extending lengthwise along the mounting.

21. A security grating assembly constructed and arranged substantially as hereinbefore described with reference to the accompanying drawings.