Patent ID: 7193835

Claim:
A device for permanently monitoring a ground for safety purposes and for preventing a risk of electrical shock to passengers on a self-guided public transportation vehicle utilizing electrical energy as a driving force and running on tires along a metal guide rail supported on a surface, the metal guide rail being connected as a ground and the vehicle using at least one self-guiding assembly governing a movable directional assembly with at least one guide wheel traveling along the metal guide rail, the device being incorporated into the vehicle to prevent the risk of electrical shock to passengers of vehicle, the device comprising: at least two electrical contact elements contacting the grounded metal guide rail wherein the contact elements are separated from one another and in contact with the metal guide rail and the contact elements together with a portion of the guide rail extending between the contact elements forming a safety loop supplied from a low voltage electrical generator with terminals (BT+ and BT−) connected to the safety loop; and a current passage detector connected to the safety loop and detecting a current flowing in the safety loop and furnishing a signal indicating whether the safety loop is one of open or closed depending upon whether electrical contact at a level of the contact elements is one of satisfactory or unsatisfactory, and when the electrical contact is unsatisfactory, the signal causing at least one of safety elements to be engaged.