Collapsible security grille, grille system, bar, and method

The invention relates to a collapsible security grille. The grille comprises a multiplicity of successive bars that can be substantially stacked in a retracted state of the grille and can be substantially spaced apart with respect to each other in an extended state of the grille. At least a number of the bars comprises one or multiple parts formed from bent sheet metal. Advantageously, each of at least a number of the bars can be put together from at least a first part formed from a first blank of sheet metal and a second part formed from a second blank of sheet metal. In particular, at least the first part can be a bent profile. Additionally or alternatively, at least the second part can be a bent profile.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is the U.S. National Stage of PCT/NL2017/050039, filed Jan. 20, 2017, which in turn claims priority to: Netherlands Application No. 2016133, filed Jan. 21, 2016, the contents of each of these applications being incorporated herein by reference in their entireties.

The invention relates to collapsible security grilles and to security grille systems with such collapsible security grille. Said collapsible security grilles can be for securing a passage such as a doorway or window at least partly. For example, the security grille may be to screen off and/or protect for instance shops, business establishments, warehouses, kitchens, schools, parking garages, etc. and/or for partitioning spaces, for instance in a shopping center or an airport terminal building.

Collapsible security grilles are for instance known from European patent publication EP 1 036 911 A2 and from applicant's international patent application publication WO 2015 115 893 A1.

Said publications disclose stackable security grilles comprising a multiplicity of successive bars that can be substantially stacked in a retracted state of the grille and can be substantially spaced apart with respect to each other in an extended state of the grille. For instance, said bars can extend substantially horizontally, and may at outer ends be guided within a guide profile or guide bar. The bars may be provided with series of corresponding through holes or passages for allowing elongated connecting elements, such as rods, to pass through at least a number of the bars. Such connecting element, preferably its upper end or lower end, can be fixedly connected to a respective one of the bars. The opposite end of the connecting element may be provided with a retainer element, in particular a thickening or lateral protruding portion such as a so-called head. The passage in the bar adjacent to the bar to which the connecting element is fixated can be wide enough to allow a shaft of the connecting element to pass, but can be narrow enough to block the retainer element of the connecting element from passing there through. One or multiple subsequent bars can have corresponding holes, preferably though holes, that are wide enough to allow the retainer element to pass through there and/or to be accommodated therein at least partly when the security grille is collapsed.

In known collapsible, especially stackable, security grilles, the bars are made from metal tubes or pipes having a substantially square or substantially rectangular cross-section. After providing said tube or pipe, an upper wall of the hollow tube or pipe is being provided with a first hole pattern and a lower wall of the hollow is being provided with a second hole pattern corresponding to the first hole pattern. Said hole patterns are usually laser cut into the respective tube wall. In the security grille of WO 2015 115 893 A1, a passage in the bar used for blocking the retainer element can be formed by a relatively narrow first hole in a first tube wall, e.g. the upper wall, for blocking the retainer element and a corresponding relatively wide second hole in a second tube wall, e.g. the bottom wall, which can allow the retainer element to enter the tube or bar such as to be kept out of sight substantially in the extended state of the security grille.

Alternatively, as seems to be shown in the figures of publication EP 1 036 911 A2, all holes may have a substantially equal diameter and the passages that are mentioned to block the retainer element, or so-called heads, can be provided by a bush or bushing that narrows the passage formed by two corresponding through holes in opposite wall sections of the tube forming the bar.

Laser cutting the holes in walls or wall section of the tubes can be difficult, time-consuming, expensive, painstaking and/or error-prone.

An object of the present disclosure is to provide an alternative collapsible, in particular stackable, security grille, and/or an alternative method for manufacturing a collapsible security grille. It is an object of the present disclosure to alleviate or solve at least one disadvantage of one or more known stackable security grilles. In particular, it can be considered an object of the disclosure to alleviate or solve at least one disadvantage mentioned above. More in particular, the invention may aim to provide a collapsible security grille which can be produced in a manner that is relatively cost efficient, relatively little prone to errors, relatively easily, and/or relatively fast. In embodiments, the invention aims at providing a collapsible, especially stackable, security grille without laser cutting holes in walls or wall sections of pipes or tubes for forming bars of the grille.

Thereto, in a first aspect, the disclosure provides for a collapsible security grille that comprises a multiplicity of successive bars that can be substantially stacked in a retracted state of the grille and can be substantially spaced apart with respect to each other in an extended state of the grille, wherein at least a number of the bars comprises one or multiple parts formed from bent sheet metal. By making one or multiple bar parts from bent sheet metal, especially formed from a respective blank of sheet metal, holes in opposite walls or wall sections of the final bar can in embodiments be formed before a substantially hollow bar is formed from said one or more bar parts from bent sheet metal. This may for instance allow that holes can be punched, e.g. while or after a blank is formed for forming the bar or a respective part of the bar. In stead of laser cutting holes in respective walls or wall sections of a purchased pipe, holes may thus be formed in a relatively cost efficient, relatively easy, and/or relatively foolproof manner.

For example, a first bar part can be formed which comprises a wall or wall section for forming an upper wall or upper wall section of the final bar. Said first wall section or wall can then be provided with holes, which holes will later form the holes in said upper wall section or upper wall of the final bar. Said holes made in said first wall or first wall section can be made without any second wall or second wall section for forming a lower wall or lower wall section of the final bar hindering that said holes are made in said first wall or first wall section, because a second bar part comprising said second wall or second wall section can be absent. Advantageously, the holes in the first wall or first wall section can be made in a first blank, before said first blank is bent in order to deform it into the first bar part. Additionally or alternatively, holes in the second wall or second wall section can be made in a second blank before said second blank is bent in order to deform it into the second bar part.

As another example, the first pattern of holes in the first wall or first wall section of the final bar and the second pattern holes in the second wall or second wall section of the final bar may be formed in a single blank and said single blank may subsequently be bent into a bar or into a bar part, especially in a manner that the holes of the first and second pattern pair up into pairs of corresponding holes for forming passages through the final bar.

In preferred embodiments, each of at least a number of the bars can thus be put together from at least a first part formed from a first blank of sheet metal and a second part formed from a second blank of sheet metal. At least the first part and/or at least the second part may then be formed as a bent profile. By composing a bar from multiple bar parts, wherein one can be slit into another one, a second bar part extending at least partly within another, e.g. first, bar part, can extend from said first bar part in order to couple two first bar parts together. This is, a second bar part may thus overlay with two first bar parts that are placed in line and succeed each other in their longitudinal direction. The second or inner bar part can then counteract that the consecutive first or outer bar parts can be moved with respect to each other in a direction substantially transverse to their longitudinal directions. As a result, relatively long bars can be composed in a relatively easy manner, which may facilitate forming relatively wide grilles that are relatively strong in a relatively simple and/or cost efficient manner.

It is noted that, in advantageous cases in which the bar is built up from at least multiple parts, neither the first bar part nor the second bar part does need to be a bent part. For instance, the first bar part does not need to be a bent part. Additionally or alternatively, the second bar part does not need to be a bent part. For example, the first bar part can be bent part forming a profile provided with a first hole pattern and holding a second part, which can be provided with the second hole patter, wherein said second bar part may for instance be formed from an unbent piece of sheet metal. As another example, the first and second bar parts can be formed as unbent parts, preferably each provided with a respective hole pattern, and one or more further bar parts, e.g. parts forming side walls of the bar, can be formed as bent parts holding the first and second parts in place.

Advantageously, the first part can be at least partly enclosing the second part. The first part may then define a hollow room for accommodating the second part at least partly in an assembled state of the bar.

In embodiments, a bar part, especially the first bar part, may comprise one or multiple supports or retaining elements. Said one or more supports or retaining elements may be for supporting a further bar part, especially the second part. Additionally or alternatively, said one or more supports may be for facilitating retaining said further bar part at least partly within the bar part provided with said one or more retaining elements or supports.

Advantageously, the two bar parts can both be bent such as to have a substantially C-shaped or U-shaped cross-section. For example, the first bar part can be formed such as to have a cross-section substantially shaped as an inverted U, having inwardly extending supports at the ends of its “legs” or strokes. The second bar part, which then for instance can be formed such as to have a U-shaped cross section, can then be positioned at least partly into a hollow space within the first part. For instance in such embodiments, the bar can have side walls or side wall sections that comprise multiple layers, e.g. two layers, whereas the bottom and upper walls or wall sections may then comprise less layers than the side walls or walls sections. In particular, the top and/or the bottom of the bar may comprise a single layer.

In embodiments, the first part and the second part can move with respect to each other to some extent. In such embodiments, the first part and the second part do thus not need to be fixedly attached to each other. For example, the second part can be moved with respect to the first bar part to at least a small extent in at least a direction substantially parallel with the longitudinal direction of the bar.

The present disclosure also relates to a method for producing a bar for a collapsible security grille and/or for producing a collapsible security grille. The method can comprise the steps of providing a first bar part from sheet metal, providing a second bar part from sheet metal, and assembling a bar from at least said first bar part and said second bar part. Preferably, the bar can be assembled at least partly by sliding the second bar part at least partly into the first bar part, especially in the longitudinal direction of the first bar part. Alternatively or additionally, the bar may be assembled at least partly by forming, e.g. folding or bending, a part at least partly around another part.

The bar parts may be prevented from sliding out of each other by means of one or more connecting elements extending through a first through hole in the first bar part and a corresponding through hole in the second bar part. Additionally or alternatively, the bar parts may be prevented from sliding out of each other by means of guiding means, e.g. guiding profiles which may limit movement of the bar and/or parts thereof in its/their longitudinal direction.

Further, the present disclosure also relates to a security grille system, and to a bar for a collapsible security grille.

Advantageous embodiments of the disclosure are described below and in the appended claims.

The embodiments disclosed herein are shown as examples only and should by no means be understood as limiting the scope of the invention or the disclosure in any way. In this description the same or similar elements have the same or similar reference signs.

FIGS. 1A and 1Bshow a first embodiment of a collapsible security grille system1having a collapsible security grille2situated in its extended state2A and its collapsed or so-called retracted state2B, respectively. It is noted that the collapsible security grille2can be a stackable security grille. The stackable and/or collapsible security grille2may be suitable for securing a passage3at least partly, and can be arranged to be brought from an extended state2A, in which the grille2can block the passage3at least partly, into a retracted state2B, in which at least a part of the previously blocked part of the passage3is unblocked.

Although the passage3, which can be formed as a door opening, in the embodiment shown inFIGS. 1A and 1Bhas a width which is smaller than its height, the collapsible security grille2and/or a security grille system1having the collapsible security grille2may in alternative embodiments have a relatively large width, preferably a width being larger than the height of the grille in extended state2A.

As can be seen inFIGS. 1A and 1B, as well as inFIGS. 2A and 2Bwhich show schematic views of a portion of a second embodiment of the security grille2in its extended state2A and its retracted state2B, the collapsible security grille2comprises a multiplicity of successive bars4. As can be seen inFIGS. 1B and 2B, the bars4can be substantially stacked in a retracted state of the grille2. Although the grille2can be retracted upwardly, as in the shown embodiments, the grille2may be retractable downwardly in other embodiments. For example, the stack of stacked bars4may then be accommodated within a cavity in the ground or floor, which cavity can then thus be located below the passage3. As can be seen inFIGS. 1A and 2A, the bars4can be substantially spaced apart with respect to each other in the extended state2A of the grille2.

It is noted that the bars4can preferably extend substantially parallel to each other and/or that the bars4may preferably be substantially horizontally extending beams4. However, in alternative embodiments, the bars4may extend in a different direction. For example, the bars4can extend substantially vertically and the grille2may be retractable in a sideward direction.

In embodiments, the bars4can be connected by means of multiple elongated connecting elements5for interconnecting respective bars4. Said connecting elements5can substantially be formed as and/or may comprise a pin or peg. Although said connecting elements5may extend substantially transverse to the longitudinal direction of the bars4and/or substantially vertically, said connection elements5may extend in a different direction in alternative embodiments. For example, the connecting elements5may in alternative embodiments extend substantially horizontally.

At least a number of the multiplicity of elongated connecting elements5may each be arranged for interconnecting two respective spaced apart bars in the extended state of the security grille2in such a manner that the respective connecting element5counteracts that a first one4A and a second one4B of said two spaced apart bars4A,4B can be moved apart substantially further with respect to each other.

Thereto, said respective connecting element5,5A can be attached to the first bar4A. Advantageously, a distal end of the connecting element5can be attached to the bar4. Said distal end may preferably be an upper end of the connecting element5in case of an upwardly extending connecting element5. For example, the connecting element5may be riveted to the bar or a respective bar part42, e.g. by means of a blind rivet. However, alternatively or additionally, the connecting element may be connected by other means, e.g. by means of bolting, screwing11, welding, etc.

Additionally, said respective connecting element5,5A can be provided with retainer element7, e.g. a thickening7or lateral protruding portion7, for limiting the distance D1over which the first and second bars4A,4B can be spaced apart in the extended state2A of the security grille2. Said retainer element7, which may be considered a retainer head7, can preferably be located at a distal end of the connecting element5, more preferably, in case of upwardly extending connecting elements, its lower end.

Said second bar4B can have a passage6,60B for allowing the second bar4B to be moved along a part, e.g. a shaft5′, of the elongated connecting element5, wherein said passage60B is arranged to block the retainer element7from passing there through. For example, at one point, e.g. at or near an upper end or side4B′ of the bar4,4B, the passage6,60B may be narrower or tighter than and at another point, e.g. at or near a lower end or side4B″ of the bar4,4B. Preferably, as in the shown embodiment ofFIGS. 2A and 2B, the passage6,60B may be smaller at a side4B′ of the second bar4B facing towards the first bar4A than at the opposite, second side4B″ of the second bar4B, which second side4B″ is facing away from the first bar4A and is facing to a third bar4C. As a result, when the grille2is being extended and the connecting element5is moving through said passage6,60B in the second bar4B, the retainer element7of said connecting element5,5A can enter into the second bar4B via a relative wide part60B″ of said passage60B and can subsequently be stopped by a relative small part60B′ of said passage60B which then can counteract that the first bar4A and the second bar4B can be moved further apart from each other.

In advantageous embodiments in which the respective passage6,60B in the second bar4B is narrowing in a direction towards the first bar4A, it can be facilitated that the respective retainer element7can be accommodated at least partly within the second bar4B in the extended state2A of the security grille2. For example, the narrowing passage6,60B in the second bar4B can be formed by a first through hole60B′ provided in a first wall section45A of said second bar4B and second through hole60B″ provided in a second wall section45B of said bar4B located opposite said first wall section45A. Said first wall section45A of the second bar4B may then be facing the first bar4A, while the second wall section45B of the second bar4B may be facing a third bar4C located at the opposite side of the second bar4B as the first bar4A.

It is noted that the third bar4C, and preferably one or more further subsequent bars4D,4E, are provided with corresponding passages61C,61D,61E for allowing the connecting element5,5A and its retaining element7to enter said passages61C,61D,61E and preferably to pass through said passage61C,61D,61E in order to enter one or more following bars4C,4D,4E. Hence, the connecting element5,5A can extend through multiple subsequent bars4B,4C,4D,4E in the so-called retracted, packed, stacked, compacted or collapsed state2B of the grille2, as can be seen inFIG. 2B. It will be appreciated that said corresponding passages61C,61D,61E in the third and further bars4C,4D,4E through which said retaining element7has to pass during the collapsing of the grille2has to be wide W1enough to allow the retaining element7to pass and should thus be wider than smallest part60B′ of the corresponding passage60B in the second bar4B which is arranged to block said retainer element7from passing there through.

In preferred embodiments, the collapsible and/or stackable security grille2can be part of a security grille system1arranged for stacking the bars4in the retracted state2B and for subsequently bringing the bars4, or at least a part of the bars4, back to the extended state2A of the grille2.

As can be seen inFIGS. 1A and 1B, as well as inFIG. 4, which shows a schematic partly cut-away cross-sectional top view a further embodiment of a collapsible security grille system1, the grille system1may for instance comprise at least one bar guide8, e.g. a guiding profile8, for guiding the bars4when moving from the retracted state2B toward the extended state2A or vice versa and/or for counteracting that the bars4, or at least respective parts thereof, can be moved in a transverse direction substantially transverse to the direction D2in which the bars4extend and substantially transverse to the direction D1in which the bars4are substantially spaced apart in the extended state2A. For example, at both lateral ends2′,2″ of the grille2, a respective bar guide8A,8B may be provided for guiding end portions4′,4″ of the bars4.

Additionally or alternatively, the grille system1may comprise an actuator, e.g. a motor, such as an electromotor, for driving the grille, e.g. from its retracted or stacked state2B to its extended state2A or vice versa.

The grille system1may comprise a moving member, preferably a lifting member, such as a cable or chain, for moving, e.g. lifting, at least a part of the bars4.

In advantageous embodiments, such as for instance in the embodiment shown inFIG. 4, the security grille system1may further comprise a chain70connected to the grille2, preferably a chain70being flexible in only one dimension and/or being roller chain70, and at least one chain limiting member71for at least locally limiting movement of the chain, e.g. in a direction in which it is flexible, such as to counteract that one or more links of the chain can be substantially moved away from a regular route along which the links move when the grille2is moved from its extended state2A to its retracted state2B or vice versa. For example, the chain70may be attached to a bottom one4Z of the bars4, e.g. by means of a connector72, such as a bolt or the like. Said bottom one4Z of the bars may have a relatively large height compared to the other bars4in order to accommodate respective connecting elements5therein in the retracted state2B of the grille2. The chain limiting member71can preferably be formed by means of a limiting profile71, which may for instance be located within and/or parallel with a respective bar guide8or bar guiding profile8.

FIG. 3Ashows a schematic perspective view of an embodiment of a bar4for a collapsible security grille2according to an aspect of the disclosure. Advantageously, the bar4may be a substantially hollow bar.

The substantially hollow bar4,4B can have a first wall section45A which during use faces towards an adjacent bar4A preceding said substantially hollow bar4B and a second wall section45D facing towards a subsequent bar4C succeeding said substantially hollow bar4B. The first wall section45A can be provided with a number of first holes62A,63A, and the second wall section45D can be provided with a number of corresponding second holes62D,63D. Respective ones62D,63D of the second holes can then form pairs62B,63B with a respective one62A,63A of the first holes. Such pair of holes62B,62D;63B,63D, for instance together with a certain portion of a hollow room43within the bar4, may then thus form a passage6through the bar4. Said pair of holes and/or said passage can allow a respective one of the connecting elements5to extend there through.

Additionally to the first wall section45A and the second wall section45D, the substantially hollow bar4can have at least two sections45B,45C defining side walls of the bar4. Each of said two side wall defining sections45B,45C can extend from the first wall section45A towards the second wall section45D or vice versa. It is noted that the elongated connecting elements may extend at least partly between two side wall sections45B,45C of the substantially hollow bar4.

Here, the bar4has a substantially rectangular cross-section. Said cross-section can have a width W4being larger then the height H4of the bar, e.g. a width W4being between 1.5 and 2.5 times wider than said height H4, preferably about 2 times wider. A relatively wide width, e.g. between 20 and 60 mm, preferably between 25 and 40 mm, such as for instance about 30 mm, can allow for relatively wide passages6, and therefore for relatively thick and strong connecting elements5, whereas a relatively small height H4can facilitate that the grille2has a relatively small height H2when its bars4are stacked in the collapsed state2B of the grille2.

However, in alternative embodiments, the cross-section may be formed differently. For example, the bars may have a relatively large height and/or a different shape, e.g. having a substantially square, circular or elliptical shape. It is noted that, for instance in case of a round or elliptical shaped cross-section, the side wall or side wall sections45B,45C of the bar4may substantially smoothly blend into the first and/or second wall section45A,45D, which may form an upper and/or a bottom wall section.

As shown in the exemplary embodiment ofFIG. 3A, the bar4can comprise two parts41,42, preferably formed from a blank of sheet metal and/or bent sheet metal, especially bent steel sheets or bent steel plates. Although, the bar4, such as the exemplary embodiment shown inFIG. 3A, may thus comprise two parts41,42, preferably both formed from bent sheet metal, the bar4may in alternative embodiments comprise more than two parts, e.g. three, four or five parts, or may alternatively comprise a single part. At least one of said one or multiple parts41,42is formed from bent sheet metal, and one or more other parts of the bar4may be formed differently, for instance may be formed as a non-bent metal sheet part.

Advantageously, the metal sheet, especially a steel sheet, can be a purchase part and/or can have a standard thickness. The thickness of the steel sheet of which one or multiple parts can be formed can for instance be about 1 mm, 1.2, 1.5 mm, 2 mm, 2.5 mm, 3 mm or 4 mm, preferably about 2 mm.

Additionally or alternatively, the metal sheet, especially steel sheet, may be pre-galvanized, pre-coated or pre-painted.

Advantageously, the metal sheet, especially steel sheet, may be provided with a zinc-aluminum-magnesium coating, such as for instance the Magnelis® coating marketed by ArcelorMittal. The zinc-aluminum-magnesium coating can be an alloy comprising, and preferably substantially consisting of, zinc, aluminum and magnesium. For example, the alloy may comprise at least 1%, 1.5%, 2% or 2.5% magnesium, such as for instance about 3% magnesium, at least 1.5%, 2%, 2.5% or 3% aluminum, such as for instance about 3.5% aluminum, and/or at least 80%, 85%, 90% or 92% zinc, such as for instance about 93.5% zinc. For example, the zinc-aluminum-magnesium coating can be applied to the sheet by means of a continuous hot dip galvanizing process.

An advantage of the zinc-aluminum-magnesium coating, especially the Magnelis® coating, can lie in its self-repairing properties. For example, holes cut, especially punched or clipped or via another shearing technique, in a pre-coated sheet will have cut edges that can be protected by such coating. The coating, especially the Magnelis® coating, can protect exposed cut edges with a relatively thin zinc-based protective film with magnesium, which prevents corrosive reactions. As a result, it may be superfluous to treat, e.g. coat, the pre-coated sheet, in particular steel sheet, more in particular a steel sheet pre-coated with a zinc-aluminum-magnesium coating, especially a Magnelis® coating, after holes have been cut, especially punched, in said pre-coated sheet.

Advantageously, each of at least a number of the bars4of a security grille2can be put together from at least a first part41formed from a first blank of sheet metal and a second part42formed from a second blank of sheet metal. At least one said bar parts41,42, and preferably both, may be bent profile. The first part41can be at least partly enclosing the second part42, and/or the first bar part41may define a hollow room43for accommodating the second part42at least partly in an assembled state of the bar4. Advantageously, the second part42can be locked within the first part41in such manner that the second part42is substantially prevented from tilting or rotation about its central or longitudinal axis, e.g. letting the bar have a substantially rectangular cross-section. This may counteract jamming of the grille2and/or may counteract that the second42, which can form an inner part42, can unintentionally come loose from the first part41by falling there out, e.g. through a slit between two opposite supports44A,44B that can be provided at lower edges of the first bar part41.

In embodiments, a bar part, especially the first bar part41, may comprise one or multiple supports44or retaining elements44. Said one or more supports44or retaining elements44may be for supporting a further bar part, especially the second part42. Additionally or alternatively, said one or more supports44or retaining elements44may be for facilitating retaining said further bar part42at least partly within the bar part41provided with said one or more retaining elements44or supports44.

Said supports44may for instance extend from a respective side wall section layer41B,41C in a substantially inward direction. For example, a first support44A extending from a first side wall section layer41B in a substantially inward direction can extend substantially toward a second support44B that is extending from a second side wall section layer41B in a substantially inward direction. Preferably, one or more supports44can be formed by bending or folding over parts of a blank. The supports44may for instance be formed by edges44of a profile41forming the respective bar part41, especially the first bar part41. Although the supports44are shaped as edges or strips, the supports may be formed differently. For example, one or both side wall section forming portions41B,41C of the first part41may be provided with one or multiple fingers for supporting the second part42.

As can be seen inFIG. 3B, the first bar part41can be bent such as to have a substantially C-shaped or U-shaped cross-section, especially formed as an inverted U having inwardly extending supports44at the ends of its “legs”41B,41C or strokes41B,41C. The second bar part42, which then for instance can be formed such as to have a U-shaped cross section, can then be positioned at least partly into a hollow space43within the first part41.

As can be seen inFIG. 3, at least one, and preferably both, of the side wall sections45B,45C of the bar4can comprise multiple layers41B,42B;41C,42C of sheet metal. Advantageously, one or both of said side wall sections45B,45C of the bar4can be put together from at least a first side wall section layer41B;41C formed by the first part41and at least a second side wall section layer42B;42C formed by the second part42.

In embodiments, the first part41of the bar4can have a first wall section41A being provided with a number of first holes62A,63A. Said first wall section41A of the first part41may form at least a part of the first wall section45A of the bar4or may alone form said first wall section45A of the bar. The first part41can further have two side wall section layers41B,41C each forming a layer41B,41C of a respective side wall section45B,45C of the bar4.

In embodiments, the first bar part41may thus comprise two interspaced side wall sections41B,41C, and said first wall section41A can then form an intermediate wall section interconnecting said two side wall sections. Said side wall sections of the first part can form first side wall section layers of the substantially hollow bar.

Additionally or alternatively, the second part42of the bar4can comprise the second wall section45D of the bar4, or at least a layer42D thereof. Further, the second part42may comprise two interspaced side wall sections42B,42C, and the second wall section layer42D can then form an intermediate wall section42D interconnecting said two side wall sections42B,42C. Said side wall sections42B,42C of the second part42can form second side wall section layers of the substantially hollow bar.

The side wall sections41B,41C of the first part41may cooperate with said side wall sections42B,42C of the second part42in order to form side wall sections45B,45C comprising multiple layers, i.e. at least two layers. Since the first part41may enclose the second part42at least partly, said first side wall sections41B,41C formed by the first part41may be located at outer sides of the second side wall sections42B,42C formed by the second part42. As a result of the multiple layers41B,42B;42B42C, the side wall sections45B,45C of the bar4may be relatively thick, relatively stiff, and/or relatively strong.

It is noted that one or both of the first and second wall sections45A,45B of the bar4can be substantially formed by a single layer of sheet metal. In embodiments in which the bar4is composed from multiple bar parts41,42, especially multiple profiles41,42, the first bar part41, especially formed as a first profile41, may comprise the first wall section45A. Additionally or alternatively, the second bar part42, especially formed as a second profile42, may comprise the second wall section45D.

For example because upper and lower wall sections45A,45D of the bar may not need to be as stiff as side wall sections45B,45C of the bar4, it can be an advantage that said upper and lower wall sections45A,45D can be relatively thin, e.g. being composed from relatively few layers, preferably comprising a single layer of sheet metal only. Hence, when a certain combined side wall section thickness, i.e. the combined thickness of the layers41B,42B;41C,42C of the respective side wall section45B,45C, is desired, material can be saved for the first and/or second wall sections45A,45D. In contrast to prior art bars from rectangular pipes, which have substantially equal wall thicknesses along their periphery, the bars made from bent sheet metal, e.g. composed from multiple bar parts, can have relatively strong, rigid and/or thick side walls or side wall sections, while having relatively thin and/or light top and/or bottom walls or wall sections. Economizing on material may not only save money due to limited use of material, but may also result in relatively light bars. Due to weight savings, an actuator for stacking and unstacking, i.e. extending, the grille2may be of a relatively light and/or cheap version.

Advantageously, the first part41and the second part42of the bar are not fixedly attached to each other, such that the second part42can be moved with respect to the first part41to some extent. For example, the second part42can be moved with respect to the first bar part41to at least a small extent in at least a direction substantially parallel with the longitudinal direction D2of the bar4. By not fixedly or completely rigidly attaching the first and second bar parts41,42to each other, the bar4and/or the grille2can allow for some play, as a result of which can be counteracted that bars4may unintentionally get stuck, e.g. in or between bar guide8A,8B guiding the grille2when being extended or collapsed.

Alternatively, or additionally, in embodiments, the grille2or the grille system1can comprise one or multiple, especially two, elongated relatively rigid guiding elements73, e.g. formed as a rod, rail, bar or tube, extending through multiple succeeding bars4. As can be seen inFIG. 4, such elongated guiding elements73may preferably be located at or near a respective end portion4′,4″ of the bar4. Preferably, the elongated guiding elements73may be located within a respective bar guide8A,8B, such that said elongated guiding elements73, which do not retract during collapsing of the grille2, will not block a part of the passage3when the grille2is in its collapsed state (seeFIG. 1B).

Due to the one or multiple elongated guiding elements73extending through through holes through the bar parts41,42of succeeding bars,4mutual movement of the bar parts41,42of a bar4, e.g. at least in their axial or longitudinal direction D2, can be limited or counteracted, which for instance can counteract jamming. An additional or alternative advantage of the guiding elements73may be that they can give extra firmness to the grille2or grille system1. For example, in the extended state of the grille2, the elongated guiding elements73can at least partly transmit forces exercised on one of the bars4to one multiple of the other bars. As a result, e.g. when one is tampering with one of the bars4, the grille2may more or less act as a whole, for instance to counteract that one of the bars is levered or wrenched out of the respective bar guide8A,8B. For instance, a tampering force applied to a certain bar may be transferred to another bar and the multiple bars may transmit the initial tampering force over different regions of the bar guide(s), which may result in a relatively strong grille system1.

Although the guiding elements73and the corresponding through holes in the bars4have a circular cross-section in the embodiment shown inFIG. 4, it will be appreciated that they may have alternative shapes, e.g. rectangular, oval, etc. in alternative embodiments.

Further, it is noted that the invention is not restricted to the embodiments described herein. It will be understood that many variants are possible.

For example, a first bar part and a second bar part do not need to have similar lengths. For example, a relatively long first bar part can hold multiple relatively short second bar parts.

Such and other variants will be apparent for the person skilled in the art and are considered to lie within the scope of the invention as formulated in the following claims.