BACKGROUND OF THE INVENTION Store-front windows, especially those displaying valuable merchandise are always subject to burglary and theft, particularly at night, on week-ends and holidays. That is why most shops in addition to locking their doors, also provide protection for the display windows against break-in by having shutters or bars. One popular form of bars, especially where the shop wants to show its wares in the display window even when it is closed, is the roll-up bar. This comprises either flat metal slats with apertures or alternately aligned wavy metal bars forming open areas, pivotally attached to each other to form a grid or web. The ends of the slats or bars are fitted into fixed end channels on both side so that the grid or web can be rolled up and down over the shop window. Locking means are also provided at the bottom and/or sides of the grid or web to hold it down when locked. The size of the apertures or openings in the grid or web will depend on the type of goods to be displayed in the window. For small display articles narrower openings will be required to prevent any thief from breaking the glass, sticking in his hand and helping himself to one or more articles. Large display articles can be protected even with grids or webs having larger apertures.

Traditionally roll-up bar were made of iron or steel. Recently, however, there has appeared on the market a roll-up window bar (Figure 1) made from aluminum slats having spaced apart apertures. Such a slat 10 is shown in Figure 2. The slat 10 is made by extruding an aluminum profile 12 (Figure 3), comprising a substantially flat center section 14 with upper 16 and lower 18 longitudinal channels. The channels 16 and 18 have J-section profiles whose respective open ends 20 and 22 face in opposite directions. The center section is substantially flat and has apertures 24 punched out at predetermined intervals to provide openings through which displays can be seen. Slats 10 can be assembled and fitted together (Figure 4) by sliding the open J-end 22 of the lower channel 18 of one slat 10'into the open J-end 20 of the upper channel 16 of a second slat 10. In this way a grid of infinite length can be assembled. The thusly fitted slats can be rolled up only in the direction of the arrow 26 because of the J-ends interlacing.

Another recent type of aluminum roll-up bar uses slats constructed from two profiles each profile having an axial channel on one side and a J-profile slit on the opposite side of the profile. Two such oppositely disposed profiles can have their J-sections slideably engaged to pivot in one direction only. Adjustable spacer plates inserted in the axial channels separate the two profiles forming a variable apertured slat that can be assembled to an infinite length.

One major problem with these roll-up bars or gates is that they require long tables to assemble the slats. The working length has to be at least twice the length of the slat in order to slide one into the other.

Another limitation of these gates and bars is that the apertures are relatively small making it difficult to see the contents of the shop window unless one comes up close to the window.

OBJECT OF THE INVENTION It is an object of the present invention to provide a new and convenient roll-up web for use in window bars.

Another object of the invention is to provide a roll-up web assembled from extruded aluminum profiles.

Yet another object of the invention is to provide an aluminum profile for making roll-up webbing for window bars.

A further object of the invention is to provide aluminum roll-up window or door bars.

A still further object of the invention is to provide a method of constructing aluminum profile roll-up webs.

BRIEF DESCRIPTION OF THE INVENTION In accordance with this invention there is thus provided an aluminum construction element for assembling together with like elements an interlocking roll-up grid or web said element comprising an extruded aluminum profile composed of three connected parallel tubes aligned in the same plane such that a middle tube is connected on two opposite sides to outer tubes, said profile having sections cut away from each of the outer tubes at predetermined intervals leaving other outer tube sections attached to the middle tube in the plane of the profile, said cut away sections and said other outer tube sections of one outer tube alternate with the cut out sections and other outer tube sections of the other outer tube, so that the other outer tube sections on one side of the middle tube of one element can be pivotably coupled with the other outer tube sections of the other side of the middle tube of a second element.

In a preferred embodiment the two outer tubes of the aluminum profile comprises channels along their lengths. The channel of one outer tube having a J-profile and the channel of the other outer tube having a profile mating with the J-profile. After cutting away sections of the outer tubes the remaining J-profile sections and mating profile channel sections can pivotally interlock two such elements.

In another preferred embodiment the middle tube is bent in the shape of a wave with one outer tube sections being at the upper crest of the wave and the other outer tube section being at the lower crest of the wave.

The elements of this invention can be assembled into a roll-up grid by placing two such elements in the same plane at a slight offset, with the lower tube sections of one element adjacent the upper tube section of the other element. The two elements can then be pivotally coupled. This coupling will depend on the specific construction of outer tube sections.

With channeled outer tube sections wherein a J-profile outer tube section engages a mating profile outer tube section, the elements are moved laterally towards each other so that the J-profile sections of one element fits into the mating profile section of the other element. Further elements can be added in the same manner to produce a grid of infinite length. If the element also has a wave pattern, then the grid will look like a web with openings determined by the size and shape of the wave.

If the construction element has outer tube sections without side channels, then it is preferable that the tube sections remaining on one side of the middle tube after cutting away sections therefrom, comprise a double tube section with a gap therebetween the width of one tube section, and the tube sections remaining on the other side of the middle tube after cutting away sections therefrom, be single tube sections that fit in between the double tube sections. When the remaining tube sections from two such elements are fitted together a rod is inserted though the holes of the tube sections coupling them together pivotally. Further like elements can be assembled in the same way to form an infinitely long roll-up grid or web.

The grid or web thus formed can be made into a roll-up bar or gate in a conventional manner by winding the grid or web around a pole and providing side channels outside a door or display window in which the grid or web ends can move up and down.

BRIEF DESCRIPTION OF THE DRAWINGS This invention will be better understood when considered together with the drawings, in which : Figure 1 illustrates a prior art roll-up grid, Figure 2 shows the single slat used in making the roll-up grid of Figure 1, Figure 3 shows the prior art profile element from which the slat of Figure 2 is made, Figure 4 illustrated the assembly of two prior art slats to make a roll-up grid, Figure 5 illustrates an aluminum extruded profile in accordance with the invention for making construction elements for roll-up bars, Figure 6 illustrates a construction element in accordance with the invention, Figure 7 shows another construction elements derived from the element in Figure 6, Figure 8 shows the element of Figure 7 inverted 180 degrees.

Figures 9,10 and 11 illustrate the assembly of the construction elements of Figures 7 and 8 into a roll-up web.

Figure 12 shows another embodiment of an extruded aluminum profile in accordance with the invention..

Figure 13 show another embodiment of a construction element in accordance with the invention.

Figure 14 is a construction element derived from the element in Figure 13.

Figure 15 is a roll-up web in accordance with the invention.

Figures 16,17 and 18 illustrate the assembly of a roll-up web in accordance with the invention.

Referring now to Figure 5 there is shown an extruded aluminum profile 30 having three adjacent connected tubes 32, 33 and 34 lying on the same plane, with tube 33 in the middle and tubes 32 and 34 on either side of it. This profile serves as precursor for a construction element 31 (Figure 6). From the side tube 32 of profile 30 there are cut out large sections A, B and C, and a small gap D leaving double tube sections 36 attached to one side of middle tube 33. From the other side tube 34 there are cut out large sections E and F leaving single tube sections 38 attached to the opposite side of middle tube 33. The double 36 and single 38 tube sections alternate along tube 33 so that the double tube sections 36 are opposite the cut out sections E and F and the single tube sections 38 are opposite cut out sections A, B and C. The gap D is slightly larger than the width of the single tube section 38 so that the latter can fit into the former.

Figure 7 illustrates a preferred construction element 40 of the invention. This element 40 is made from element 31 by bending the cut out sections A, B, C, E and F to form waves with the double 36 and single 38 tube sections at opposite apexes of the waves. Figure 8 shows the construction element of Figure 7 turned around about its axis 180 degrees and is herewith designated 42.

There will now be described a method of assembling construction elements 40 and 42 into a roll-up web with reference to Figures 9,10 and 11. Construction element 40 is positioned above construction element 42 in an offset manner so that the single tube sections 38 of element 40 are aligned in the gap D between the double tube section 36 of element 42 thus mating tube sections 36 with tube sections 38 along the entire length sections 36 and 38 along the entire length (Figure 10), pivotally connecting the two elements 40 and 42. This process is continued by adding a further construction element 40 (Figure 11), and more, until the desired web length is obtained. The length of each element can theoretically be infinite depending on the length of the basic extruded profile 30. It is possible to further renforce the web in accordance with the present invention, by threading a cable through the hole of the middle tube 33 which will make it much more difficult to cut through the element. Such a web can be used to make a roll-up gate to protect doors and windows.

Figure 12 shows another extruded aluminum profile 50 which is a precursor for a construction element in accordance with another embodiment of the invention. The profile 50 also has a hollow middle tube 52. On either side of tube 50 there are aligned slit tubes 54 and 56 along the same plane forming channels. The upper tube 54 forming a J-profile channel 58 and the lower tube 56 forming a complementary channel 59 able to pivotally engage the J-channel to pivot in only one direction.

This aluminum profile 50 is made into a construction element 58 (Figure 13) as follows. From the upper tube 54 of profile 50 are cut out sections G, H, I, J and K, leaving J-profile sections 53 attached to the top of middle tube 52. From the opposite tube 56 there are cut out sections L, M, N and O, leaving complementary channel sections 55 on the opposite side of middle tube 52 thereby forming construction element 58. The J-profile section 53 and complementary channel section 55 alternate along opposite sides of tube 52, each being opposite the cut out section of the other side of tube 52. In a preferred embodiment, element 58 can be modified by bending it into a waved construction element 60, as shown in Figure 14, with the J-profile sections 53 and complementary channel sections 55 on opposite apexes 57 and 59 of the waves.

A roll-up web (Figure 15) is assembled from construction elements 60 as illustrated in Figures 16,17 and 18. Two construction elements 60 and 62 are placed one above the other in an offset manner so that the J-profile sections 53 are above the middle tube 52 and the complementary channels 55 are below the tube 52 (Figure 16). By moving either element 60 or 62 to the right or left the J-profile sections 53 of element 62 will engage the complimentary channels 55 of element 60 to form the first stage of a web (Figures 17, 18). This process is continued by adding more construction elements 60 until the desired web length is obtained (Figure 15). The length of each element can theoretically be infinite depending on the length of the basic extruded profile 50.

It is possible to further reinforce the web in accordance with the present invention, by threading a cable through the hole of the middle tube 52 to make it much more difficult to cut through the element. One major advantage of the invention is that the space required to assemble a roll-up web is minimal, a little more than the length of the construction element, because the J-profiles and channels on each element are spaced apart to enable the complementary channel and J-profile to engage over a very short distance.

We found that in order to bend the straight construction elements to form waves it is best to apply direct force against the cut out sections of the middle tube and at the same time apply an angular counter force to the middle section i. e. a pulling force opposite and at an angle to the direct force.

It will be appreciated by persons skilled in the art that the scope of the present invention is not limited to what has been shown and described hereinabove, merely by way of example. Rather, the scope of the invention is limited solely by the claims which follow.