A security grille

Abstract: A collapsible security grille is provided comprising two conventional face-to-face arrays of rigid grille bars (2, 9) pivotally interconnected at their intersections, characterized in that all the pivotal connectors (4) are uniformly and non-adjustably spaced apart along their respective grille bars in one said array, but are free, as far as the second array is concerned, to undergo small sliding displacements along the grille bars of that array. In this way the stresses that ordinarily lead to jamming, jerky action and noise are automatically compensated at the point and instant of their origin. It is preferred that the pivotal connectors around the periphery of the second array are likewise non-adjustably spaced apart, so that every such connector at a grille bar meeting point (6) (as distinct from a crossing point 8) is spaced from both of the two next adjacent crossing-point connectors (8). A spacer member (7) suitable for this purpose can be made integral with a pivotal connector, and can be made in two parts (28, 30) for length adjustment prior to use. The length of the spacer in use determines the pitch of the grille.

Description: This invention relates to a collapsible security grille for screening and freeing at will a doorway, a window aperture, a skylight, the space above a bar or counter, or any other passable opening to which it is desired to deny access at certain times, but not at others. A known construction of expanding and collapsing security grille comprises, supported in a non-collapsible frame, a first array of rigid elongate parallel uniformly spaced-apart grille bars, and a second, similar array in close face-to-face proximity to the first, wherein the grille bars of one said array are inclined and disposed with respect to those of the other array to produce meeting points of two grille bars at the periphery of the grille, and to produce crossing points of two grille bars inside said periphery, and also comprises pivotal connectors which interconnect the two adjacent grille bars at each meeting point and crossing point. Such a security grille is herein called a grille of the type described. Grilles of the type described are treated in, for example, British Patent Applications GB 2 224 073 A and GB 2 183 716 A. Properly constructed, a grille of the type described depends for its smooth operation, when expanding and collapsing, on the uniformity of spacing between adjacent pivotal connectors in a given grille bar. Minute departures from such uniformity are believed to accumulate along and across the grille and give rise to jamming, jerky action, noisy operation and other defects. The pivotal connectors are commonly rivets. Rivets are disadvantageous in that they are subject to wear and distortion, that they often produce objectionable noise when the grille is expanded and collapsed, and that those of ferrous metal are liable to corrosion. The holes drilled in the grille bars to accept the rivets must be placed with great precision if jamming or jerky action is to be avoided. Such precision is costly and difficult to achieve, and may be wasted if irregularity is reintroduced by wear, distortion and corrosion of rivets. US Patent 3,338,289 discloses a folding gate including a mesh of which the examples given are standard and known forms of mesh including strips (16) arranged in two sets with those of each set pivoted to the other, in the usual way. Pivoting is provided by means of pins (26) or shafts (58) which form rivets each securing a member of one set of strips (16) to a member of the other. If any such rivet is free to move longitudinally of either of the strips (16) pivoted together thereby, the specification is silent about it. Australian Patent No 596065 discloses a collapsible security screen including a grille (15) which comprises a lattice work of elongate members (21) pivotally connected together at the points of [notional] intersection of the members, the latter being arranged in two sets which are for convenience considered to be co-planar. Nothing is said of the connections beyond the fact that they are pivotal. In particular there is no suggestion that any of the connection means is free to move longitudinally of either of the two elongate members connected together thereby. It is an object of the invention to overcome or substantially ameliorate at least some of the above-mentioned disadvantages. Another object is to provided a security grille which operates smoothly, silently and with a lubricated feel. The invention accordingly provides a collapsible security grille which comprises, supported in a non-collapsible frame, a first array of rigid elongate parallel uniformly spaced-apart grille bars (2) and a second, similar array in close face-to-face proximity to the first, wherein the grille bars (2) of said first array are inclined and disposed with respect to those (9) of the second array to produce meeting points (6) of two grille bars at the periphery of the grille, and to produce crossing points (8) of two grille bars inside said periphery, and also comprises pivotal connectors (4) which interconnect the two adjacent grille bars at each meeting point and each crossing point, and wherein each grille bar (2) in the first said array has all its pivotal connectors (4) uniformly and non-adjustably spaced apart along its length , characterized in that, in the second said array, at least some of the pivotal connectors (4) and the associated grille bars (9) are free to undergo small sliding relative displacements along said grille bars (9) of that array, of magnitude sufficient to compensate articulation stresses during grille expansion and contraction. In the grille of the invention, therefore, the pivotal connectors in the first array are fixed, each on its respective grille bar of that array, but the pivotal connectors of said second array are displaceable along their respective grille bars to a small extent sufficient to compensate for the spacing irregularities that give rise to jamming and the other defects mentioned. Thus the grille automatically suppresses said defects in the course of expanding and collapsing, which gives a smooth movement and a lubricated feel to both procedures. Preferably each grille bar in the second said array has each of its meeting-point pivotal connectors non-adjustably spaced apart from its respective adjacent internal or crossing-point pivotal connector, the spacing in every case being the same as the aforesaid uniform spacing in the bars of said first array. In a preferred grille of the invention, therefore, the displaceable pivotal connectors of the second array are those of the central region of said array, ie all connectors with the exception of the peripheral connectors and their immediately adjacent non-peripheral connectors. This provision is preferred because it enhances the smoothness of the grille movement. To effect this uniform non-adjustable spacing of pivotal connectors, each grille bar preferably has a retaining formation into which the pivotal connectors can be inserted and then moved to their appointed places. A spacer rod is provided, likewise insertable into the retaining formation and movable into abutment with the positioned pivotal connector, thus retaining the latter in its place. The pivotal connectors used at the peripheral meeting points, however, are fixed and non-displaceable, so as to prevent their escape from the ends of the grille bars. These peripheral meeting-point pivotal linkages, or better, every second such linkage, may be provided with rollers captive within a frame of hollow guide rails for travel therein during expansion and collapse of the grille. The distance travelled may be substantial, (compared with the grille dimensions) as it is in the two guide rails which extend in the direction of grille expansion and collapse, or it may be minimal, as in the other two opposed guide rails, wherein the distance travelled by the captive rollers is limited by and to the change in the width of the grille consequent on its change in length during expansion and collapse. In a given grille, all the spacer rods are equal in length. The spacing of pivotal connectors effected by the spacer rods is a standard distance called the pitch of the grille. It is essential that the pitch be uniform over the whole area of the grille. To produce grilles that differ from one another in pitch, spacer rods of appropriate length must be used. Preferably the retaining formation is afforded by the cross-section of the grille bars, a desirable cross-section being C-shaped with the tips of the limbs of the C defining the edges of a slot that extends along said bar, and leads to a channel thereinside. Preferably each pivotal connector (other than the peripheral or meeting-point ones) is dumb-bell shaped, having at each of its ends a respective head of a size to enter the channel of a grille bar from one end of said channel, but too big to escape through the aforementioned slot. At least one of the pivotal connector's heads has a circular profile to enable the pivotal connector to function as a pivot pin. Preferably the shaft of the "dumb-bell" bears a median extension, such as a disc coaxial with said shaft, to act as a washer or spacer between the pivotally interconnected grille bars so as to prevent their abrading each other or making noise in use. For this purpose among others the pivotal connector can be of stainless steel, brass or other metal, but is preferably made of low-friction plastics material such as Nylon (TM) 6, Perlon (TM), glass-filled Nylon (TM) or the like, while the grille bar is preferably an extruded section of metal such as an aluminium alloy, which may be anodized or coated to improve its corrosion resistance. Each peripheral or meeting-point pivotal connector may comprises a pivot pin passing through aligned bores in the ends of the grille bars, said bores being desirably lined with respective flanged sleeves, the flanges in use lying between the grille bars to prevent contact between them, in the manner of washers. Preferably every second peripheral pivotal connector is of this kind, the others being equipped with guide rollers, as will be described later. The pivot pin and sleeves are preferably made from hard-wearing plastics material, such as Nylon (TM). A useful and economical embodiment of the invention provides a pivotal connector united with a spacer rod as an integral moulding. The pivotal connector is at one end of the spacer rod, so that the latter can be supplied longer than any foreseen grille requires, and can be simply cut at its free end to the overall length appropriate for the grille in hand. In another useful embodiment the spacer rod, with or without a pivotal connector integrally formed on one of its ends, is adjustable in length before assembly of the grille. Preferably the spacer rod comprises two separable portions having respective complementary formations such as two arrays of teeth selectively interengageable to provide a spacer rod of a desired length. The cross-sectional dimensions of the thus length-adjusted spacer rod are such that it can enter and occupy the retaining formation (such as the C-channel) in a grille bar but once in, its parts cannot separate, as that requires relative movement of the portions transversely of the grille bar, for which movement there is insufficient room in the channel cross-section. A useful refinement is a peripheral spacer rod which, with or without an integral pivotal connector at one of its ends, bears an abutment formation at its other end, having a housing for the roller means mentioned above. The abutment formation ensures that the terminal spacer rod, preceded by the integral pivotal connector, having entered the retaining formation of a grille bar, can penetrate thereinto to the desired distance and no further. The invention is explained in greater detail in the following description of a particular and preferred embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which Fig 1 is an elevation of a collapsible security grille for a counter top; Fig 2 is a perspective view of two lengths of grille bar from the grille of Fig 1, arranged to form a crossing point; Fig 3 shows the bar lengths of Fig 2, seen as if pivoted into alignment and then longitudinally sectioned; Fig 4 is a perspective view of a first part of a two-part spacer rod with pivotal connector, for use in the grille of Fig 1; Fig 5 is a perspective view of the second part of either of the two-part spacer rods, the first parts of which are shown in Figs 4 and 6; Fig 6 is a perspective view of a first part of a two-part spacer rod without a pivotal connector, for use in the grille of Fig 1; Fig 7 is a perspective view of a short piece of grille bar as used in the grille of Fig 1; Fig 8 is a perspective view of the second part of either of the two-part spacer rods, the first parts of which are shown in Figs 4 and 6; Fig 9 is a perspective view of the part shown in Fig 8, taken from the other or opposite face thereof to that shown in Fig 8; Fig 10 is a side elevation of a meeting point of the ends of two grille bars of the type shown in Fig 2, equipped with a pair of rollers; Fig 11 is a section in end elevation of the meeting point of Fig 10, showing in addition a channel member in which the rollers are captive; Fig 12 is a section in end elevation of a meeting point similar to that of Fig 10, but with a fixed pivot pin and without rollers; and Fig 13 is an elevation of a collapsible security grille for an upright window aperture. Referring now to the drawings, beginning with Figs 1 and 2, a security screen or grille 1 comprises a first array of channelled grille bars 2 and a second, similar array of grille bars 9, similar to grille bars 2, the second array being to the rear of the first array as seen in Fig 1. Each grille bar 2 has a retaining channel 3 (Fig 2) along its length. Each grille bar 2 captively retains in its channel 3 a plurality of pivotal connectors 4 about their respective first ends 5. Spacer rods 7, all of equal length, are disposed within channels 3 between neighbouring pivotal connectors 4 to maintain said connectors in a spaced apart configuration defining intersection points 6, 8 as will be explained. The second array, namely that of grille bars 9, has respective retaining channels 10 along the length of each. The grille bars 9 of said second array are presentable into respective engagement with the complementary second ends 11 of the pivotal connectors 4 so that associated grille bars 2 and 9 are rotatably engaged at intersection points 6, 8 and pivotally movable between an extended and a retracted configuration of the security grille 1. The intersection points 6, 8 comprise meeting points 6 around the periphery of the grille 1, and crossing points 8 spread across the interior of said grille. Further spacer rods 7, again of length equal to that of the aforementioned spacer rods 7, are disposed within channels 10 of grille bars 9 one at either end of each said bar 9, thus spacing apart the pivotal connectors 4 of each meeting point 6 and its neighbouring crossing point 8. The grille 1 is mounted for movement within a frame 15 which is peripherally abutted about an opening across which the grille is to be extendible. The opening may be, for example, a door or a window opening. The frame 15 includes two opposed generally vertical open-channelled frame members 16, 17 joined by horizontally disposed base and top frame members 18 and 19. The top frame member 19 incorporates a downwardly extending cover 22 for accommodating alteration in the height of the grille 1 during extension and collapse thereof. As the horizontal extent, or length, of grille 1 is increased to move the channelled grille bars 2, 9 into an extended configuration, the vertical extent, or height, will decrease. The height variation is accommodated by a movable frame member 20 slidably mounted within frame members 16 and 17. The meeting points 6 of the grille bars 2 and 9 along frame members 20, 16 and 18 and a grille lead rail 23, or preferably alternate said meeting points 6 (every second one) are locations for attachment of respective carriages 50 which facilitate sliding movement of the grille within its half fixed (16, 18), half movable (20, 23) frame. The carriages 21 are best illustrated in Figs 10 and 11, and will be described in more detail later. The meeting points 6 not having attached carriages 50 have simple pivot pin connectors 59 (Fig 12). Member 20 is continually maintained in a substantially parallel attitude with respect to the base frame member 18 in order to maintain a uniform shape and size of the rhombic pattern unit of the grille 1. To achieve this effect, member 20 slidably engages frame members 16 and 17 and rests on compression springs 24 supported on brackets 25 within said members 16 and 17. In the extended configuration of the grille 1, movable member 20 will be adjacent to brackets 25 because the springs 24 are almost fully compressed. Alternative and preferred embodiments include only a single spring 24 and bracket 25 in one only of the frame members 16 and 17. One effect of the spring(s) 24 is to cushion the grille approaching closure, so that a small additional manual force is necessary to close, latch or lock it. Referring in particular to Figs 2 and 3, the pivotal connector 4 is dumb-bell shaped and comprises a shaft 27, end heads 5 and 11 and a central, coaxial washer member 26 for spacing the grille bars 2, 9 apart, as seen in Fig 3. Although not appearing in the drawings as a self-contained, separate part, the pivotal connector 4 can be provided as such. Referring to Figs 4 - 9, the aforesaid spacer rod 7 is presented as a two-part rod, comprising separable portions 28 (Fig 5) and 30 (Fig 6) adapted for interengagement to produce a spacer rod 7 of preselected length. Interengaging formations 35 and 36 give a spacer bar of mean length 133 mm, adjustable 12 mm above and below the mean. Adjustment is effected by a movement of the separate portions 28, 30 transversely of their length to bring them out of engagement at a given overall length and then into engagement at a desired overall length. A projection 33 on portion 28 fits into a recess 34 in portion 30 to accommodate the formations 35, 36 so that the assembled spacer rod 7 fits the channels 3, 10 of grille bars 2, 9, and cannot be dismantled while it remains therein. Instead of part 30, a part 31 (Fig 4) may advantageously be employed, which incorporates a pivotal connector 4 by integration with one head 5 of said connector. The length of part 31 thus exceeds the length 1 of part 3 by an increment equal to that length of channel 3 which is occupied by head 5; this sizing preserves the constancy of the pitch. Instead of part 28, a part 29 (Figs 8, 9) may usefully be employed which bears an integral abutment formation 38, having the same cross-section as a grille bar 2, 9. The formation 38 is perforated by a bore 39 which can serve for accommodating the pivot pin 59 shown in Fig 12, or the roller spindle 51 shown in Figs 10 and 11. The formation 38 also bears an annular eminence 39a surrounding one end of the bore 39. In use, to assemble a peripheral or meeting-point junction of the security grille, two spacer members 7, each consisting of a part 29 and a part 31, are inserted into the free ends of grille bars 2, 9 respectively, so that the two annular eminences 39a lie face to face, their height combining to equal the thickness of a washer member 26 of pivotal connector 4. A pivot pin 59 is then inserted to occupy both of the bores 39, and may have a snap-action retaining formation to secure it (Fig 12). Alternatively a spindle 51 is inserted through the bores 39, and a pair of rollers 54, 55 is fitted to the projecting ends of the spindle (Fig 11). This assembly produces a carriage 50 which can be captively retained in a channel rail 56, which may function as any of the frame members 16, 18, 20 or 23 (Fig 1) aforesaid. Each of rollers 54, 55 includes on its outer face an axially extending protrusion 57 for providing a point contact with the wall of channel rail 56 in which carriage 50 is retained. Preferably, the protrusions are conical. It is preferred that rollers 54 and 55 are maintained in rotatable mounting with spindle 51 by the sides of the channel rail 56 through which carriage 50 is to move. However, other embodiments include fixing means for ensuring the rollers remain mounted to spindle 51. For example, the spindle can include two spaced apart annular detents for snap locking engagement with respective complementary indents in rollers 54 and 55. Conical protrusions 57 preferably have their apexes aligned with spindle 51 and are configured such that any twisting of spindle 51 during relative movement between grille bars 2 and 9 results in a larger surface area of the rollers being presented into engagement with the edges of the channel rail 56. This has the effect of allowing a small degree of twisting of spindle 51 so as to facilitate movement of the grille, while preventing any jamming of the rollers in the channel. For openings of non-standard sizes the length of the grille bars 2 and 9 and the spacing between intersection points can be adjusted to ensure an appropriate sizing of the grille in the extended configuration. The spacing adjustment can either be achieved by: (a) producing specialized spacer bars 7 for each particular application; (b) producing a standard length of spacer bar 7 which is then cut to size; or (c) using the spacer bar variations as illustrated in Figs 4-9 and appropriately adjusting the portions to produce a bar of desired length. Referring to Fig 13, a collapsible grille 40 for a sales point is constructed similarly to the security grille of Fig 1. It contains adjustable spacer bars as described in connection with Figs 4-9. The outer, non-collapsible frame consists of frame members 41, 42, 43, 44 and the grille, made up of grille bars 2, 9, has a leading edge held by a movable rail 45. A rivet 46 anchors a median, peripheral, grille bar meeting point within the top frame member 41. A second rivet 47 anchors a median, peripheral grille bar meeting point within the movable rail 45. The effect of the rivets 46, 47 is to centralize the grille 40, impose bilateral symmetry on it, and thereby further improve the smooth and fluent expansion and collapse of the grille in use, in addition to the qualities of operation and feel imparted by the first mentioned embodiment of the invention. Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that it may be embodied in many other forms. For example, an electric motor or other apparatus can be used to assist in moving the grille between the extended and retracted configurations. Furthermore, some embodiments include an integral fly screen which collapses when the grille is retracted and which may be constructed, for example, like a conventional roller blind. Such a fly screen may be completely enclosed within, for example, frame member 16 when in that collapsed configuration.

Claims: A collapsible security qrille which comprises, supported in a non-collapsible frame, a first array of rigid elongate parallel uniformly spaced-apart grille bars (2) and a second, similar array in close face-to-face proximity to the first, wherein the grille bars (2) of said first array are inclined and disposed with respect to those (9) of the second array to produce meeting points (6) of two grille bars at the periphery of the grille, and to produce crossing point (8) of two grille bars inside said periphery, and also comprises pivotal connectors (4) which interconnect the two adjacent grille bars at each meeting point and each crossing point, and wherein each grille bar (2) in the first said array has all its pivotal connectors (4) uniformly and non-adjustably spaced apart along its length , characterized in that, in the second said array, at least some of the pivotal connectors (4) and the associated grille bars (9) are free to undergo small sliding relative displacements along said grille bars (9) of that array, of magnitude sufficient to compensate articulation stresses during grille expansion and contraction. A security grille according to Claim 1 characterized in that each grille bar in said second array (9) has each of its meeting-point pivotal connectors (4) non-adjustably spaced apart from the respective next adjacent internal or crossing-point pivotal connector, the spacing in every case being the same as the aforesaid uniform spacing in the bars (2) of said first array. A security grille according to Claim 1 or 2 characterized in that each grille bar (2, 9) has a retaining formation (3, 10) into which a pivotal connector can be inserted and then moved to its respective appointed place, and the spacing is effected by spacer rods (7), each likewise insertable into the retaining formation (3, 10) so as to position a respective pivotal connector (4), while those pivotal connectors which are used at the peripheral meeting points are fixed and non-displaceable. A security grille according to Claim 3, characterized in that the retaining formation is afforded by an internal cross-section (3, 10) of the grille bars (2, 9). A security grille according to Claim 4, characterized in that said cross-section (3, 10) is C-shaped, with the tips of the limbs of the C defining the edges of a slot that extends along said bar (2, 9), and each pivotal connector (4) (other than the peripheral or meeting-point connectors) is dumb-bell shaped, and has at each of its ends a respective head (5, 11) of a size to enter the channel (3, 10) of a grille bar (2, 9) from one end thereof, but too big to escape through said slot. A security grille according to claim 5, characterized in that each pivotal connector has intermediate its heads a transverse extension of its shaft, serving as a washer (26) to prevent contact between the associated grille bars. A security grille according to any of Claims 3 - 6, characterized in that at least some of the spacer rods (7, Fig 2) are integral with respective pivotal connectors (4), one per spacer rod. A security grille according to any of Claims 3 - 7, characterized in that at least some of the spacer rods (7) are integral with respective abutment formations (38) restricting their possible depth of insertion into the retaining formation, one said abutment formation per spacer rod. A security grille according to any of Claims 3 - 8, characterized in that at least some of the spacer rods (7) are made in two parts, comprising separable portions (28, 30) adapted for interengagement to produce a spacer rod of preselected length. A security grille according to any previous claim, characterized in that a median, peripheral, grille bar meeting point (46) in the anchored edge of the grille is secured against movement transverse to the direction of grille expansion and contraction, and a similar point (47) in the leading edge of the grille is secured to a grille lead rail (45) against movement along said lead rail, both anchorages serving to impose bilateral symmetry on the grille (40) and thereby improve the smoothness of expansion and contraction thereof.

Inventors: DONNELLY FRANCIS MARTIN, DONNELLY, FRANCIS MARTIN
Applicants: DONNELLY FRANCIS MARTIN, DONNELLY, FRANCIS MARTIN
Application year: 1993
Main classification: E06B9
IPC codes: E06B9