Node element for a furniture system having a three-dimensional load-bearing tube structure

1. A furniture system having a three-dimensional load-bearing tubular structure, comprising a plurality of tubes and a plurality of three-dimensional electrically conductive node elements,

wherein at least one of the tubes has two mutually insulated current conductors for carrying, respectively, current of a first polarity and current of a second polarity along the tube,

wherein the node elements each comprise a plurality of connection points for mechanically fastening two or more of said plurality of tubes to the node elements and

wherein at least one of the node elements has two conductive regions to carry electrical current of said first and second polarities, respectively, said two conductive regions being insulated from each other by an insulative region,

wherein the two mutually electrically insulated regions of the at least one node element connect the currents of the two electrical polarities to the two mutually insulated current conductors of the at least one tube at the connection points for the tube,

whereby said furniture system is configured, following the mechanical fastening of the at least one tube to the at least one node element, so that the two mutually insulated current conductors of the at least one tube are electrically connected to the two mutually electrically insulated regions of the at least one node element,

wherein the furniture system further comprises connectors joining the node elements to the tubes at the connection points of the node elements, creating, an electrical connection between the node elements and the tubes attached thereto,

wherein the two mutually insulated current conductors for carrying current in said at least one of the tubes are arranged coaxially to each other, and

wherein the at least one tube comprises a structural tube element made of a conductive material, which constitutes a first of the two mutually insulated current conductors and serves to carry the current of the first polarity, and an inner conductor insulated from the structural tube element for carrying the current of the second polarity, which constitutes a second of the two mutually insulated current conductors, said first and second conductors being insulated from each other by said insulative region.

2. The furniture system according to claim 1 , wherein the first of the two mutually electrically insulated regions of the at least one node element is constituted by an outer part made of a conductive material, and wherein a second of the two mutually electrically insulated regions of the at least one node element is constituted by an inner part made of a conductive material, and wherein the outer part and the inner part are electrically insulated from each other by an intervening separation layer of electrically insulating material.

3. The furniture system according to claim 2 , wherein current of the first electrical polarity is carried on the outer part of the at least one node element.

4. The furniture system according to claim 2 , wherein the inner part of each node element has threads for fastening of the two or more tubes.

5. The furniture system according to claim 4 , wherein a first of the two electrically insulated regions includes an outer surface of the outer part of the node element and a second of the two electrically insulated regions comprises said threads.

6. The furniture system according to claim 2 , wherein the outer part and the inner part are produced from a metallic material.

7. The furniture system according to claim 1 , wherein the connectors create a mechanically loadable fastening between a contact element and the tube attached thereto.

8. The furniture system according to claim 1 , wherein the connectors comprise:

a) a mechanical fastening element associated with a tube to be fastened to a node element and a screw for tensioning said mechanical element, wherein the screw is configured to cooperate with a thread of one of the node elements, and

b) an electrical contact element for contacting the screw and the inner conductor of the tube held by the mechanical fastening element.

9. The furniture system according to claim 7 , wherein the connectors comprise:

a) a mechanical fastening element associated with a tube to be fastened to a node element and a screw for tensioning said mechanical element, wherein the screw is configured to cooperate with a thread of one of the node elements, and

b) an electrical contact element for contacting the screw and an inner conductor of the tube held by the mechanical fastening element.