The present invention relates to a flooring system, mainly for sup¬ ports for farm animals in stables, consisting of plate-shaped frames, preferably grates, which have crossing longitudinal and transverse ribs, one pair of opposite lateral edges of a frame being equipped with horizontal connecting means, and the other pair of opposite late¬ ral edges being equipped with toothings which are able to interact with corresponding toothings on the lateral edge of an adjacent frame, and which toothing comprises a U-shaped track pointing downwards for placing in a supporting rail so that the frames are able, when placed adjacently, to form a flooring with an unbroken surface and at the same time are connected horizontally and vertically.

Such flooring is known from the German Gebrauchsmuster 8009170.9. The floorings disclosed therein are made up of frames which are equipped with a toothing on one pair of opposite sides. The spaces and tips of the toothings are equipped with recesses and corbels in order to form an almost unbroken surface, so that it will be nearly impossible to take out an individual frame from the centre of a constructed floor. This is important when the frames are used in buildings for farm ani¬ mals.

It is the object of the present invention to provide a flooring of the type mentioned initially which presents the same advantages, and which provides an improved safety against unintended removal of a frame from the centre of the floor, and which is at the same time easy to produce in a moulding form.

According to the present invention this is obtained by a flooring which is characterized in that said downward track is delimited by the under side of each projected tooth and two lateral walls, the first of which consisting in a downward wall which is connected to the tip of each tooth and which is perpendicular to the under side of the tooth, and the second lateral wall consisting in the lateral faces of the frame or in flanges which are projecting from such a lateral face, and that said first lateral wall, at the end facing the tip of the tooth, extends beyond the tip of the tooth in a direction parallel with the track.

At the tip of each tooth, a projected edge is formed by the first side wall's upper sides which extend beyond the tip. These projected edges are able to interlock under the innermost edges of a tooth on a cor¬ responding frame placed adjacently in order to form the flooring. He- reby an unintended removal of a frame in the centre of a flooring will be made difficult or even impossible. Since each lateral wall extends, beyond the tip of the tooth, a contact surface is formed at the upper side of the first lateral wall, which contact surface will engage with the under side of the teeth which delimit a tooth space into which a tooth in question is inserted. These upper sides or contact surfaces will be formed at either side of the track and will thus cause an in¬ terlocking of both adjacent frames to be obtained.

With an advantageous embodiment as described in claim 2, a relatively large contact surface may be obtained at the upper side of the lateral wall, and increased safety against unintended removal of a frame is obtained. Because of the tapering, a snap device will make it possible to press the teeth into tooth spaces although the lateral walls are wider than the actual distance between the lateral edges of the adja- cent teeth.

The frame is easy to manufacture by moulding of resin material since the plane of the lateral wall upper sides which form the contact sur¬ faces will be provided in the same moulding plane as the under side of the toothings. Thus the frames may be moulded in a very simple mould¬ ing form.

It should be noted that the flooring system is primarily intended for use in stables and particularly in pigsties where increased safety against unintended removal of the flooring has to be provided. How¬ ever, the flooring may also be applied elsewhere, e.g. in tents and caravans where it is desirable to provide a firm flooring in an easy and simple way. Due to the toothings and the efficient interlocking established according to the present invention, such a flooring is able to form a plane floor with a very plane surface where there is no risk that the planeness of the flooring will be broken even under heavy loads along the lateral edges of any frame.

At the lateral edges placed opposite the- toothed lateral edges, the

individual frames are equipped with any connecting means which may be known per se and which provide a vertical interlocking of two adjacent frames. Thus these elements may consist of projecting pins on one la¬ teral edge and corresponding grooves or holes in the opposite lateral edge.

DESCRIPTION OF THE DRAWINGS

The invention will now be further explained with reference to the ac¬ companying drawing, wherein

Fig. 1 shows a perspective view of a frame for a flooring according to the invention, Fig. 2 a fragmentary partial view, seen from above, of a frame for a flooring, Fig. 3 a view, seen from aside, of the fragment shown in Fig. 2 and Fig. 4 a view, seen from the end, of the fragment shown in Figs. 2 and 3.

Fig. 1 shows a frame 1 in the form of a grate intended as a support surface for pigs. Other embodiments of the frame are possible. The grate 1 is equipped with crossing longitudinal and transverse ribs 2, 3. Horizontal connection means 6 are formed on two opposite lateral edges 4,5. The illustrated connection means 6 consist of perforations of the lateral edge 5 which interacts with projecting pins (not shown) at the opposite lateral edge 4.

The other two opposite lateral edges 7,8 are equipped with toothings 9,10. The toothings 9,10 are designed to engage with each other and are equipped with downwardly open U-shaped tracks 11, intended for placing on a supporting rail (not shown) so that the grates 1 when placed adjacent to each other form an unbroken flooring surface. As can be understood, a number of the shown grates 1 may be laid down to form a flooring in which a connection is provided horizontally and vertically.

The toothings 9,10 consist of a number of identical teeth 12 which are offset from one another, and two teeth 13, which may be called tooth halves in a popular term, at either end of one lateral edge 8. Either of the U-shaped tracks is delimited by the under side 14 of the pro-

jecting tooth 12,13, said under side in the embodiment shown is formed on the under side of a supporting rib 15 placed under the tooth 12,13. The supporting rib 15 is connected with a downward orientated support¬ ing rib 16 on the outside of the lateral wall 17 which delimits the frame or the grate 1. For the sake of simplicity, the ribs 16 are not shown in figs. 1 and 3. The downward tracks 11 are further delimited, by the inner side 18 of the first lateral wall 19, which is connected with the tip 20 of the tooth and which is substantially perpendicular to the under side of the tooth. On the other side the track 11 is de- limited by the upper side of the flanges 16 which project from the lateral walls 17 of the frame.

As appears most clearly from Fig. 2, the first lateral walls 19 in a direction parallel with the track 11 extend on either side of the tip 20 of the tooth. When two grates 1 are placed on a supporting rail to form a flooring, the surfaces 21 turning upward and extending beyond the tip 20 will be situated at the root 22 of each adjacent tooth 12,- 13 and will join the under side of the tooth 12, 13. Thus an unintend¬ ed removal of a grate in the centre of a floor will be made impossib- le.

The projecting surfaces 21 will easily pass a root 22 of a tooth when the lateral edges 23 of a lateral wall 19 are designed with a downward tapering. The interlocking is particularly easy to establish when the downward tapering extends according to one angle at the lower portion 24 of the lateral wall and according to a different and wider angle at the upper portion 25 of the lateral wall. The angle is measured ac¬ cording to a vertical axis of symmetry 26 which passes through the lateral wall 19, and which defines at the same time a vertical plane of symmetry 27 through a tooth 12.

As it appears most clearly from Fig. 2 each of the lateral edges 23 will be inclined towards the centre at an angle which substantially corresponds to the angle which a tooth flange 28 forms with the plane of symmetry 27.

As it appears from Fig. 4, the first lateral wall- 19's downward late¬ ral edge 29 (see Fig. 3) is equipped with a bevelling 30 inclined to¬ wards the centre. This facilitates placing the grate 1 on a supporting

rail

The shown grate 1 may be produced by moulding a resin material in a very simple moulding form because a dividing line is established at the level which defines the contact surfaces 21 and which at the same time defines the under side of each tooth 12,13.

Although the frames described will primarily be produced from resin materials, it will also be possible to produce the grate in cast iron and obtain the same advantages, of safe interlocking which prevents unintended removal of a grate which forms part of a flooring according to the invention.