DESCRIPTION

Background of the Invention

A thin-walled plastic tube can be knurled so as to produce a crinkled or corrugated form. This can be extended or compressed, and it can be bent into different shapes which are maintained over time. A common example of this is the bendable drinking straw, in which there are two straight smooth sections joined by a compressed, knurled section normally up to 10mm long.

However, it has recently become possible to knurl a plastic tube with a wall as thin as that of a drinking straw to a length in excess of 50mm. In doing so, the tube can be bent and extended to produce complex shapes.

Statements of Invention

According to this invention there is provided a construction kit comprising a plurality of deformable, "structurally dead", tubular elements each having a corrugated wall so as to be bendable and expandable, and a plurality of connectors for interconnecting adjacent end portions of said tubular elements in line with one another.

The term "structurally dead" means that the element has a substantially non-resilient character such as to retain the shape into which it is bent.

The connectors may be short lengths (e.g. less than 10mm) of tube for insertion into the adjacent end portions. Alternatively, the connectors may be externally applied elements.

Additional connection means, e.g. adhesive, may be provided to interconnect the exterior of tubular elements directed at non-zero angles to one another.

Alternatively, to interconnect tubular elements directed to one another at a non-zero angle, a V-shaped cut-out may be provided intermediate the ends of a tubular element for insertion therein of an end portion of another tubular element.

Description of Embodiments of the Invention

Embodiments of the invention will now be described with reference to and/or as illustrated in the accompanying drawings.

These embodiments employ thin-walled plastic tubes that are knurled so as to provide a crinkled or corrugated form. These tubes can be extended or compressed (that is, they are longitudinally expandable and compressible), and can be bent into different shapes which are maintained over time. Such knurled tubes, which can be in various colours, can be used as the building units for a construction kit. Their tubular form provides solidity to the construction, and allows for the tubes to be connected to one another. As a result, models of different shapes and sizes can be made. Moreover, the corrugated tubes can be expanded or compressed like a concertina. For example, a 50mm compressed tube can be

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SUBSTITUTE SHEET RULE 26 pulled out to a length greater than 100mm (Figure 1 ). This enables models to be constructed using fewer tubes.

The tubes can be joined together lengthwise by inserting a straight (preferably tubular) plug into both open ends. However, if two curved tubes are being joined together, then the area of contact between the straight plug and the curved walls of the tubes could be very small and the tubes could slip apart (Figure 2). In order to increase the area of contact and thereby effect a more permanent link, it might be necessary to lengthen the plug. But in doing so the curvature of the tubes would be compromised (Figure 3). Therefore, it is preferable that the link should be able to bend into the desired curved shape and remain there. To achieve this, a smaller diameter close-fitting knurled tube (e.g. 5mm diameter) is inserted into the end of a larger diameter (e.g. 6mm) curved tube, thereby effecting a curved link (Figure 4). By this means it is even possible to form a complete circle from one or more corrugated tubes.

The tubes can be joined laterally (i.e. at a non-zero angle) by the use of clips or adhesive. The latter method is simpler and cheaper. In order to avoid the mess created by flowing glue, it is advantageous to apply small globules of viscous glue (sold as 'glue dots').

To join two tubes at right angles, a globule of glue can be stuck to the end of one straw and then pressed against the side of the other (Figure 5). It may be beneficial to insert a tight- fitting lesser diameter link into the end of the straw so as to increase the surface area to which the glue is attached. However, if the two tubes contribute to the structural integrity of the model, then the right-angle relationship may be likely to sag over time due to stretching of the adhesive bond.

In order to establish a permanent right-angle join, an aperture, e.g. a V-shaped cut out or a hole with a diameter approximately equal to a second tube's diameter, is cut in the wall of a tube. The end of the second tube is then inserted into the aperture, the tight fit ensuring that it remains in place (Figure 6). If the join is too loose, a globule of glue can be applied to the end of the second tube so that when inserted it adheres to the wall of the receiving tube.

So, for example, if the wall of a model house is being built, then the right angles of its frame would be constructed by making holes in the sides of the tubes, whilst the area within the frame can be filled with extended horizontal tubes cut to the required length and stuck at their ends to the uprights of the frame. If round shapes are to be filled, then the ends of the tube can be cut at suitable angles so that they will fit into the space.

To make a cross-beam, two holes of equal size are cut in the extended tube's wall, directly opposite one another. Another tube can now be pushed through the holes (Figure 7).

Alternatively, an extended link can be pushed through the holes and two tubes can be pushed over the protruding ends (Figure 8). If the joins are loose, then they can be secured with glue spots.

The ability to stick the tubes together, cut them at different angles and make apertures in them enables the production of models composed of many varied configurations and shapes. This provides the elements of a construction kit with enormous flexibility.

Additionally, the tubes can be re-used. This is usefully achieved by inserting a smooth-

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SUBSTITUTE SHEET RULE 26 surfaced, rigid tube, of lesser diameter, fittingly into and along the whole length of the knurled tube. If the latter is curved then it can be straightened by manipulating it as the straight tube is pushed through. The ends of the knurled tube are then pushed together to form a reconstituted straight, compressed tube.

The following statements provide expressions of the disclosure herein:

A1. A construction kit comprising a plurality of deformabie, structurally dead, tubular elements each having a corrugated wall so as to be bendable and expandable, and a plurality of connectors for interconnecting adjacent end portions of said tubular elements in line with one another.

A2. A construction kit according to statement A1 , wherein the connectors are shorter lengths of tube (e.g. less than 10mm) for insertion fittingly into the adjacent end portions.

A3. A construction kit according to statement A1 , wherein the connectors are externally applied elements.

A4. A construction kit according to any one of statements A1 to A3, wherein additional connection means, e.g. adhesive, are provided to interconnect the exterior of tubular elements directed at non-zero angles to one another.

A5. A construction kit according to any one of statements A1 to A3, wherein, to interconnect tubular elements directed to one another at a non-zero angle, an aperture (e.g. a hole or a V-shaped cut-out) is provided intermediate the ends of a tubular element for insertion therein of an end portion of another tubular element.

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