This invention relates to playthings and in particular is concerned with interlocking elements of light weight sheet plastics material suitable for fabricating a toy model building structure such as a dolls house.

BACKGROUND ART

There is an established and on going demand for toy model building structures and elements for utilisation in such models. Consequentially numerous such structures and building elements are known. However, there appears an unfulfilled demand for a toy dolls house type model structure that is of a light but robust nature and that is readily assembled from a compact kit-set. In a kit-set form such a model can be conventionally handled and stored rendering it particularly suitable for sale to a recognised market namely the travelling public. A first object of this invention is to provide a model building structure readily erectable from planar elements. Thus in a demounted or kit-set mode the model is adapted for compact packaging and handling. A further object is to provide such a model fabricated from light weight but robust material. This not only enhances the transportation of the model as aforesaid but also provides that the model is easily handled by a child. Further, the model is of an appropriate strength to withstand the rigours of use as can be reasonably expected with such a plaything.

DISCLOSURE OF INVENTION According to a first aspect of this invention there is provided interlocking model structure elements comprising a pair of planar body elements each formed from plastics materials and consisting of a pair of adjacently spaced apart surface membranes separated in substantially parallel relationship with one another by webs extending therebetween at intervals and in parallel relationship with one another,

characterised in that in a first of the elements a tab forming incision is cut transversely to the webs to extend therethrough and through one only of the membranes, the unsevered membrane articulately retaining the tab to the parent body of the element and with folding of the tab thereabout an inner tab edge being formed, and in a second of the elements a cut extending completely therethrough, the cut consisting of a primary section and at least one secondary end section whereby the material subtended by said sections of said cut can be marginally deflected as to off-set at least the edge of the subtended material associated with the primary section of the cut from the plane of the parent material to enable insertion of a tab of a first element into the cut, and with folding of the tab about its line of articulation, abutment of the off-set edge of the subtended material against the inner edge of the tab to thereby interlock the two elements together.

According to a second aspect of this invention there is provided interlocking model structure elements as described in the preceding paragraph wherein the thickness of the membranes and the webs of an element are minute relative to the overall thickness of an element.

According to a third aspect of this invention there is provided interlocking model structure elements as described in either of the two preceding paragraphs wherein the elements are formed from polypropylene plastics material.

According to a fourth aspect of this invention there is provided interlocking model structure elements as described in the preceding paragraph wherein at least one of the elements is provided with a slot of a width marginally narrower than the thickness of an element and a third element is provided also formed of the same material as the first and second elements, the third element being formed with a fixed

extending tab disposed parallel to the associated webs of the parent material and incorporates at least two webs within the tab whereby with insertion of a fixed tab into a slot the edges of the slot impinge onto the membrane material between two adjacent webs of the fixed tab to pinch-fit the two elements together.

BRIEF DESCRIPTION OF THE DRAWINGS

In further describing the invention reference is made to the accompanying drawings of a preferred embodiment wherein;

Fig 1 is a perspective unassembled view of the elements, and Figs 2 and 3 are sectional views on line A-A on Fig 2, depicting an intermediate stage and complete interlocking stage respectively of the elements, and Fig 4 is a perspective unassembled view of an additional interlocking means of the elements, and Fig 5 is a sectional view on line B-B on Fig 4 depicting the elements of Fig 3 interlocked together.

BEST MODE FOR CARRYING OUT THE INVENTION

Model structure elements 1 and 2 suitable for constructing a toy building such as a dolls house are preferably fabricated by cutting the elements from a planar sheet of parent material. The sheet is formed from plastics material preferably polypropylene with sheets of various colours being utilised as required. The sheet material comprises a pair of surface forming membranes 3 separated by webs 4 (some only being shown in broken line for clarity) extending therebetween, the webs 4 extending in parallel relationship with one another in one direction only through each of the elements 1 and 2. Preferably the webs 4 are disposed at regularly spaced apart intervals with the thickness of the membranes 3 and webs 4 being commensurate and being minute relative to the overall thickness of the sheet. For example,

the sheet may be some 3 mm in overall thickness and the webs 4 and the membranes 3 each some 0.1 mm in thickness. A type of such sheet material is marketed under the trade mark "Corflute"

Thus the sheet material is of a lightweight but robust construction and by selection of the required base plastics material relatively inexpensive to manufacture rendering it particular suitable for use in fabricating playthings. Further, the material is readily printed upon enabling a variety of structural features such as windows, doors, representations of brickwork, weather-boards, tiling, and landscape features such as lawn, roads and footpaths to be depicted thereon. Thus, before the cutting-out of variously shaped elements required for a model construction from a common sheet the features required to be displayed thereon can be pre-printed as required.

A preferred model fabricated from various structural elements of the invention is a dolls house dwelling or similar and with appropriate changes in the layout and the printing on the elements 1 and 2 it is envisaged that a variety of visually different dwellings can be achieved from one set of elements. For convenience the interlocking features have been described with respect to first, second, third and fourth elements. However, it will be apparent from the following description that any of the elements may incorporate the features characteristic thereof more than once. Further, in addition to their particular characterising features any element may also incorporate the characterising features of any one or more of the other elements.

A first element 2 incorporates a tab 5 forming incision 6 disposed transversely of the webs 4 to extend therethrough and through one membrane 3 but not the other thereof.

Preferably the incision 6 merely cuts into the material without removal of any of the material. To enable a tab 5 to be folded along the line of the incision 6 the incision 6 needs to be open ended. That is, the incision 6 needs to extend either between true edges 7 and/or an edge(s) created by folding the parent material transversely of the incision 6. With the bending of the tab 5 to a disposition substantially normal to that of the parent material an inner tab edge 8 is formed.

As more particularly described hereinafter such a tab 5 enables interlocking mounting with a complementary cut 9 in a second element 1. It is found that this provides ample strength and the nature of the plastics material enables flexing thereof a multitude of times without any tangible reduction in the integrity of the material. The incision approach can also be utilised to provide a hinge such as for doors or windows.

A first element 2 such as described above may take a variety of forms to be utilised as a wall, roof, fence, floor or similar element. Within a particular construction of say a dolls house several differently configured and/or printed elements may incorporate the aforesaid features of a first element 2 of this invention.

In a second element 1 cut 9 is formed completely therethrough the cut 9 consisting of a primary section 10 and at least one secondary end section 11. Typically a secondary section 11 of such a cut 9 is substantially shorter than a primary section 10 thereof. The secondary section 11 of the cut 9 enables the adjacent material 12 subtended within the angular formation of the cut 9 to be deflected sufficiently (as depicted on Fig 1) to enable insertion of a tab 5 of a first element 2 to thus interlockingly mount a first element 2 and a second element 1 together.

More particularly, the deflection is sufficient to off-set at least the edge 13 of the subtended material 12 associated with the primary section 10 of the cut 9 from the plane of the parent material. It will be appreciated that where one end section 11 only is formed the deflection is less restrained adjacent the secondary section 11 thereof and becomes more restrained toward the opposing end of the cut 9.

With this deflection of the material a tab 5 can be aligned with and inserted into the primary section of a cut 9.

Referring in particular to Fig 2 and Fig 3, following such insertion the tab 5 is folded about its line of articulation to abut the off-set edge 13 of the subtended material 12 with the inner edge 8 of the tab 5. In so doing the subtended material 12 tends to revert to its normal planar position to also thus impinge onto the edge 14 of the cut 9 opposite edge 8 of the first element 2 to interlock the two elements 1 and 2 together essentially at right angles to one another as depicted in Fig 3.

Referring in particular to Fig 4 and 5, in an alternative interlocking arrangement a third element 14 is provided with a slot 15 of a width the same or preferably marginally less than the overall thickness of the sheet material. A fourth element 16 is formed with an extending tab 17 disposed parallel to the webs 4 and extending sufficiently to provide that at least two webs 4 fall within the tab 17. With insertion of the tab 17 into the slot 15 it is found the edges of the slot 15 impinge onto the membrane 3 material between two adjacent webs 4 of the tab 17 to provide a pinch- fit of the tab 17 within the slot 15.