Patent ID: 7744375

Claim:
A signal transmission device for connection between a first electrical connector disposed at a truck-tractor of a towing vehicle and a second electrical connector disposed at a trailer of the towing vehicle for transmission of electric signals, the signal transmission device comprising: first and second magnetic holders for attaching the truck-tractor and the trailer respectively; a third electrical connector mounted to the first magnetic holder for connecting the first electrical connector; a fourth electrical connector mounted to the second magnetic holder for connecting the second electrical connector; a stretchable coil tube; and a cable spirally inserted through the stretchable coil tube and provided with two ends electrically connected with the third and fourth electrical connectors respectively, wherein each of the magnetic holders comprises a magnetic base for attaching one of the truck-tractor and the trailer of the towing vehicle, and a bracket mounted on the magnetic base to support one of the third and fourth electrical connectors, wherein the bracket comprises a plurality of connection members pivoted to one another; at least one of the members is pivoted or fastened to the magnetic base and another one of the connection members holds one of the third and fourth electrical connectors.