The invention relates to a connection system, comprising a panel, a support for supporting the panel and an electrically conductive connecting member provided with a head and a shank for fastening the panel and the support to each other, wherein a top side of the panel which, in a fastened position of the connection system, faces away from the support, is provided with a coating layer having a lower electrical conductivity than the connecting member, and preferably the support, wherein, in the fastened position of the connection system, the head is at least partially accommodated in a recess of the panel and the shank passes through the panel and is fastened to the support in such a way that the panel is retained between the head and the support. Such a connection system is known in the prior art. The known connection system is used in intermediate floors, for example in an intermediate floor of a building used to store goods. The intermediate floor comprises panels which are attached to a support. In the known connection system, the panel is a substrate with a melamine coating layer and the connecting member is a self-tapping screw with a countersunk head and a shank which, in the fastened position of the connection system, is screwed through the panel and into the support. Due to the relatively poor electrical conductivity of the melamine coating layer of the panel, a static charge may be produced when objects are moved across the panel. When, for example, self-propelled vehicles drive across the panels, the electronics present therein could suffer interference due to a discharge of static electricity.

It is an object of the present invention to provide a connection system by means of which the build-up of static charge in the panel is minimised and wherein an increased electrical conductivity of the surface is produced. This object is achieved by the connection system according to the invention, wherein the head of the connecting member is provided with a flange which bears against the top side of the panel in the fastened position of the connection system.

An advantage of the connection system according to the invention is the fact that the flange produces a relatively large contact surface between the connecting member and the coating layer of the panel. This results in a discharge of static electricity from the coating layer via the connecting member to an electrical conductor and/or earthing means which is preferably situated underneath, for example to the support. It should be noted that a lower electrical conductivity may be interpreted as a higher electrical resistance.

In a particular embodiment, the head comprises a head part which is fixedly connected to the shank and a ring, wherein the ring is provided with the flange and, in the fastened position of the connection system, the shank passes through the ring and the ring is between the head part and the panel is retained in the longitudinal direction of the shank. In this case, the ring forms a separate component and the head part forms a single part with the shank. For example, if the head part and the shank form a screw, during fastening, the ring may retain a fixed position with respect to the panel and the head part may turn with respect to the ring. This minimizes the risk of damage to the coating layer by the flange.

The ring may comprise a recess for accommodating at least a portion of the head part. As a result thereof, the head part only has to protrude slightly above the ring, if at all, in the fastened position of the connection system.

Interacting parts of the head part and the recess may be conical. As a result thereof, the head part and the ring may be retained with respect to each other in a direction at right angles to the shank. In addition, a substantial contact surface may be produced between the head part and the ring by means the conical surfaces, in such a way that a good electrical charge transfer can take place via these surfaces. Preferably, the ring is made of brass, because this material is a good conductor of electrical current.

Preferably, the flange is situated on an axial end of the ring, which end, in the fastened position of the connection system, faces away from the support in order to make the ring protrude as little as possible over the top side of the panel.

Preferably, the abovementioned ring is partially countersunk, i.e. the ring is situated partially inside a bore or another recess in the surface of the panel. Preferably, the ring for the largest axial dimension is countersunk and preferably only the abovementioned flange protrudes above the surface.

Preferably, the flange is at least partially pushed into the top side of the panel. More preferably, a slanting side of the flange is pulled into the thickness of the coating layer partially or at least along the entire thickness. Such embodiments have the advantage that a close contact can be achieved between the flange and the top side of the panel. As a result thereof, discharge of static electricity from the coating layer via the connecting member is improved still further.

Preferably, in the direction facing away from its axis, the flange is bent in the direction of the underside of the panel. This ensures that the flange is securely pushed into the top side of the panel, without resulting in a very close contact between the flange and the coating layer of the panel. This improves the discharge of static charges.

The thickness of the flange may gradually decrease in an outward direction thereof. As a result, a sharp upright edge at the location of the ring can be minimised.

The design of the ring is preferably such that the head part of the fastening member is completely countersunk therein. Preferably, the flange has a limited thickness, for example, inter alia the limited thickness in its axial direction, for example in such a way that the ring protrudes less than 5 mm, or 3 mm or less, above the surface of the panel. Each of these design features separately and in combination ensures that the fastening member does not form an obstacle, or hardly, for, for example, self-propelled robots, in particular for the wheels thereof, which can thus be spared premature wear.

The shank may be provided with screw thread for screwing the shank into the support. This may be a self-tapping screw thread. If the support is made, for example, from thin- walled metal, the use of a self-tapping screw is efficient.

The coating layer may comprise melamine which is applied to a substrate, for example in the form of a melamine-soaked paper sheet, via a laminating process.

The coating layer may contain electrically conductive additives in order to achieve a conductivity which is closer to that of the materials from which the connecting member and, if desired, the support are made. To this end, it is possible to use, for example, the additives which are known per se for laminate floors from EP 1 567 334.

The number of connecting members per square metre of the panel may be greater than 4, preferably between 4 and 12 or between 4 and 8, in order to create a sufficient number of locations for discharging static electricity.

It will be clear that the abovementioned connecting member preferably provides an electrically conductive connection to an electrical conductor which is situated on the underside of the abovementioned panel, wherein this conductor is preferably directly or indirectly connected to an earthing means. The electrical conductor may, for example, comprise the abovementioned support, which may then be earthed as such, and has a higher electrical conductivity than the abovementioned coating layer. According to another possibility, or in combination therewith, the abovementioned panel may be provided with a conductive film/foil or layer on its underside, such as with a metal foil or layer, wherein this film/foil or layer is preferably directly or indirectly connected to an earthing means. The connection to the earthing means may be brought about, for example, by contact with a conductive and earthed support. The invention will be explained below in more detail by means of drawings which show an exemplary embodiment of the invention in highly diagrammatic form and in which:

Fig. 1 shows a cross-sectional view of an intermediate floor in which a connection system according to the invention is used.

Fig. 2 shows an enlarged view of a part of Fig. 1 which illustrates the intermediate floor in its unmounted position.

Fig. 3 shows the same view as in Fig. 2, in which an exemplary embodiment of the connection system according to the invention is illustrated.

Fig. 4 shows the same view as in Fig. 3, but shows a part of Fig. 3 on an enlarged scale.

Fig. 5 shows, in the same view as in Fig. 4, an alternative embodiment of the flanged ring.

Figs. 6 - 12 show, in the same view as in Fig. 4, further embodiments of the flanged ring.

Fig. 1 shows a part of an intermediate floor in a building. The intermediate floor is composed of panels 1 which are laid on a support in the form of a supporting structure comprising beams 2. The panels 1 are provided with interacting coupling means, in this case a tongue and a groove. In this case, the beams 2 of the supporting structure are made of a stainless steel plate material and is therefore readily electrically conductive. The panels 1 each have a substrate 3 made of chipboard, the top side of which is provided with a melamine coating layer 4, for example in the form of a melamine- soaked paper sheet which is fixed onto the substrate 3 via a laminating process. Fig. 1 shows that mutually opposite edge portions of a panel 1 are situated on two parallel beams.

Because melamine is a poor electrical conductor, static charge may be produced in the coating layer 4 when moving objects across the intermediate floor of the panels 1. The present invention provides a connection system for fastening the panels 1 to the beams 2 which minimizes the build-up of static charge. The connection system is explained by means of Figs. 2-4. Fig. 2 shows a recess 5 in the panel 1 and Fig. 3 shows that a connecting member is situated in the recess 5. Fig. 3 shows the connection system in a fastened position.

The connecting member has a head 6 which is in itself subdivided into, on the one hand, a head part 7 of a self-tapping screw with a shank 8 and, on the other hand, a ring 9 through the shank 8 passes and which, in the illustrated fastened position, is situated partially under the head part 7. In the fastened position illustrated in Fig. 3, the head part 7 and the ring 9 are situated partially in the recess 5 of the panel 1. In this position, the shank 8 passes through the panel 1 and is screwed into the beam 2 of the supporting structure. The panel 1 is thus retained between the ring 9 and the beam 2. In the illustrated exemplary embodiment, the head part 7 is provided with a depression for accommodating an matching Allen key, but several alternatives are conceivable for this. As can clearly be seen from Fig. 3, the flange is partially pushed into the top side of the panel.

Fig. 4 shows the ring 9 on an enlarged scale. The ring 9 is made of brass and is therefore a good electrical conductor. The screw, which comprises the head part 7 and the shank 8, is also made of an electrically conductive material, for example stainless steel. One axial end of the ring 9 is provided with a flange 10 which, in the fastened position of the connection system, bear against the top side of the panel 1, see Fig. 3. Thus, the ring 9, via the flange 10, forms a relatively large contact surface with the relatively poorly electrically conductive coating layer 4.

Fig. 4 shows that the thickness of the flange 10 gradually decreases in its outward direction. As a result thereof, an upright edge which extends from the top side of the panel 1 is minimised at the location of the ring 9, which is an advantage if it is desired that the top surface of the intermediate floor is as smooth as possible. Fig. 4 furthermore shows that the ring 9 comprises a conical depression for accommodating a conical portion of the head part 7 of the screw which fits therein.

Fig. 5 shows, in the same view as in Fig. 4, an alternative embodiment of the ring 9 with flange 10. In the direction facing away from its axis, the flange 10 is bent in the direction of the underside of the panel. As a result thereof, the flange can readily be pushed into the top side of the panel. This ensures close conductive contact of the flange with the coating layer of the panel. Figs. 6 - 12 show, in the same view as in Fig. 4, further embodiments of the ring 9 with flange 10. In the embodiments from Figs. 6, 7 and 8, the flange 10, in the direction away from its axis, is bent in the direction of the underside of the panel. In Figs. 11 and 12, the flange is bent in the other direction. In the embodiments from Figs. 9 and 10, the flange 10 contains a surface (in Fig. 9 the bottom surface and in Fig. 10 the top surface) which will come to lie parallel with the surface of the panel in which the ring is used.

The invention is not limited to the exemplary embodiments illustrated in the drawings and described above which may be varied in various ways without departing from the scope of the invention.