GB2271370A - A grating - Google Patents

Abstract

A grating comprises a first and a second group of intersecting bars with at least the bars (1) of the first group evenly spaced over the grating plane. The bars (2) of the second group form bar pairs which are connected to one another by means of a coupling profile (4) which extends the length of the bar pair and is penetrated by the bars (1) of the first group. The coupling profile can be in the form of a rectangular tube (6, Fig 4) in which the bar pairs are inserted and which has perforations along its broad sides through which the bars of the first group can be inserted to lie between the bars of the second group. <IMAGE>

Description

A GRATING The invention relates to a grating comprising a first and a second group of intersecting bars. At least the bars of the first group are evenly spaced over the grating plane.

Such gratings are generally known in a wide variety of configurations and shapes and serve, for example, to foil escapes from and break-ins into buildings. Hence, the wall openings for windows are generally barred in prison security wings to prevent escape when windows are open or damaged. The grating consists of intersecting bars spaced over the plane of a wall opening, the ends of which are either directly inserted into the soffit of the wall opening or in angled form and anchored in the masonry, or are fixedly welded to a steel frame fitted with anchor elements which are themselves anchored in the masonry at their ends projecting from the frame. At the points where the bars intersect, they may be welded to one another or joined in a nonpositive manner by other means, e.g. by diagonally arranged clamps or round anchor plates and suchlike.Bars in one group may also be passed through the bars of the other group. However, this means higher production expenditure and, if the bars to be penetrated are not reinforced accordingly, these may be weakened along fracture cross-sections in the intersection areas.

However, it is absolutely impossible to produce an arrangement with bars passing through one another at feasible expense, if the bars are made of a material or combinations of materials which in the finished state are highly resistant to changes in shape.

Therefore, grating bars manufactured using ceramic inserts, for example, are known whereby the characteristics of the bars, necessary to prevent them being sawn through, prevent the machining necessary to manufacture the perforations.

Bar profiles of various structures, which are commercially feasible to manufacture, are available for gratings with adequate resistance to being sawn through and destroyed.

However, since grating bars manufactured herefrom are restricted in their resistance to bending, the joint at the intersections of the bars of a grating must be much stronger and long bar sections without any intersection must, moreover, be avoided. The lastmentioned requirement may indeed be met by a corresponding decrease in the spacing between bars of both intersecting groups of bar However, narrowing the ba; fipasang reasons of cost and on optical grounds.A decisive disadvantage of narrow bar spacing with respect to security results from the following: Bar sections within a grating segment may be moved back and forth more easily and eventually broken off as a result of material fatigue using a crowbar, the longer the power arm and the shorter the work arm is of a crowbar acting as a lever. If the grating segment is relatively narrow, a crowbar need only penetrate the grating plane on a short section to engage two bar sections defining the grating plane on a short section to engage two bar sections defining the grating segment on two opposite sides with only a relatively small pivoting angle. The length ratio of power arm to work arm is therefore the greater, the shorter the spacing between opposite bar sections of a grating.

The object of the invention is to provide a grating of the above-described type, which may have relatively large grating segments, allows strong joints to be formed at the points of intersection of the grating bars and provides highly effective protection for bar sections between the points of intersection against conventional bending stresses.

This object is achieved by a grating of the type outlined in the first paragraph hereto, characterised in that the bars of the second group are provided as bar pairs, of which one bar is arranged on one side and one bar on the other side of the bars of the first group so as to lie opposite one another, and the bars of each bar pair are connected to one another by means of a coupling profile which extends the length of the bar pair and is penetrated by the bars of the first group.

By arranging the bars of the second group in pairs according to the invention, the bars of the first group are superimposed by bars of the second group on both sides of their assembly plane. The pairs of bars are preferably aligned perpendicular to the assembly plane of the first group of bars so that an increase in the number of bars used does not change the size of the grating segments in any way.

The gap between these pairs of grating bars is completely blocked by the coupling profile connecting the grating bars of each bar pair so that the relatively short distance between them, which preferably corresponds to the diameter of the grating bars of the first group, does not allow a bar pair to be levered apart. Namely, a crowbar or similar cannot be inserted between the grating bars of one bar pair, which by means of the coupling profile forms a closed unit.

The arrangement of passing the grating bars of the first group through the coupling profiles not only results in intersection points, which are technically simple to manufacture and which are prepared merely by providing the coupling profiles with perforations corresponding to the cross-section of the grating bars of the first group, but also results in intersection points, which may be firmly fixed by simple weld joints by positioning welding runs around the passage areas between the grating bars of the first group and the coupling profiles.

According to one embodiment of the invention, the coupling profiles comprise a flat steel web, which is welded at least in some sections along its two longitudinal sides onto opposite longitudinal lines of the bars of a bar pair.

The grating bars of a bar pair may be fixedly joined via the flat steel web, in which case the space between the grating bars of the bar pair is completed blocked. Gratings of any size may be assembled simply from bars of the first group and correspondingly prefabricated bar pair units of the second group provided with flat steel webs.

Advantageously, in embodiments of the invention, each coupling profile is provided with a number of perforations corresponding to the number of bars in the first group, the cross-section of these perforations being adapted to be a positive fit with that of the bars of the first group.

Therefore, corresponding coupling profiles may be prefabricated by the metre and may be cut to the length of the bar pairs they are to be used for.

All bar pairs of a grating are preferably positioned in a parallel arrangement at the desired spacing and then the bars of the first group intersecting them are pushed through the perforations in the coupling profiles of the bar pairs.

Preferably, only then, according to one embodiment, is each bar of the first group welded to each coupling profit at least over part of its periphery.

A completely different embodiment of the invention provides that the coupling profiles each comprise a rectangular tube enclosing a bar pair.

This embodiment provides the technically eminent advantage that bar pairs may be formed from the second group of grating bars without welding work or similar by simply inserting two bars in each case in each rectangular tube after, or preferably before, the grating bars of the first group have been passed through perforations which are preferably provided in the centre of the broad sides of the rectangular tube. After all the grating bars have been inserted and passed through and have been correctly aligned, the intersection points may then be fixed to the grating bars of the first group by welding the rectangular tubes.

Two examples of a grating according to the invention are illustrated in the accompanying drawings, in which: Figure 1 is a view onto a grating part section of a first embodiment; Figure 2 is a section along line II-II in Figure 1 through the vertical grating bars; Figure 3 is a section along line III-III in Figure 1 through the horizontal grating bars; and Figure 4 is a section through the vertical grating bars of a second grating embodiment.

As shown in Figure 1, a grating part section comprises intersecting horizontal bars 1 of a first group and vertical bars 2 of a second group, which define a grating segment 3.

As can be seen in Figures 2 and 3, bars 2 of the second group are arranged opposite each other on both sides of the first group so that bars 2 form bar pairs.

The bars 2 of each bar pair are joined by a coupling profile 4 or 4', which, in a first embodiment according to Figures 1 to 3, is formed from a flat steel web 5 and, in a second embodiment according to Figure 4, from a rectangular tube 6.

Each coupling profile 4 comprising a flat steel web 5 is welded along both its longitudinal sides to opposing longitudinal lines of the surface of the bars 2. At the points where the bars 1 intersect, each flat steel web 5 is provided with perforations 7 to permit bars 1 to pass through so that at their points of intersection, the bars 1 may then be welded to all the flat steel webs 5 of the grating.

Each coupling profile 4' comprising a rectangular tube 6 is also provided with perforations 7' on its broad sides on a level with the areas of intersection, through which bars 1 may be passed, and may be welded to the rectangular tube 6 in the positions provided, preferably before bars 2 are inserted into the rectangular tube 6 on both sides of bars 1, thus forming bar pairs which are connected to one another by the rectangular tube 6.

Claims (6)

1. A grating comprising a first and a second group of intersecting bars, wherein at least the bars of the first group are evenly spaced over the grating plane, characterised in that the bars of the second group are provided as bar pairs, of which one bar is arranged on one side and one bar on the other side of the bars of the first group so as to lie opposite one another, and the bars of each bar pair are connected to one another by means of a coupling profile which extends the length of the bar pair and is penetrated by the bars of the first group.

2. A grating according to Claim 1, wherein the coupling profiles each comprise a flat steel web which is welded at least partially along its two longitudinal sides onto opposite longitudinal lines of the bars of each bar pair.

3. A grating according to Claim 1, wherein the coupling profiles each comprise a rectangular tube enclosing a bar pair.

4. A grating according to any of Claims 1 to 3, wherein each coupling profile is provided with a number of perforations corresponding to the number of bars of the first group, the cross-section of these perforations being adapted to be a positive fit with that of the bars of the first group.

5. A grating according to any one of Claims 1 to 4, wherein each bar of the first group is welded to each coupling profile at least over part of its periphery.

6. A grating substantially as hereinbefore described with reference to and as illustrated by Figures 1 to 3 or Figure 4 of the accompanying drawings.