Abstract: A material handling vehicle guidance system comprises a first conductive member, a second conductive member, and an electrical current source. The second conductive member is electrically coupled to the first conductive member and extends parallel to the first conductive member to define a loop. The first conductive member and second conductive member are coupled to a shielded cable connector. The electrical current source supplies current to the first conductive member in a first direction and supplies current to the second conductive member in a second direction opposite the first direction to produce a narrowcast radio frequency signal detectable between the first conductive member and the second member.

Abstract: A system for controlling the movement of carriages in a conveyor system is disclosed in which individually powered carriages are controlled so as to stop a carriage at a designated position on the conveyor rail. Electrical contact wires extend along the conveyor rail and are electrically connected to controller units on each of the carriages by electrical contacts sliding along the electrical contact wires. Certain ones of the electrical contact wires have electrical discontinuities which define boundaries of first and second zones. The electrical discontinuities form a normally open electrical circuit with the controller units of each of the carriages, thereby keeping such controller units in the inoperative or "off" position. In this position of the controller unit, the power unit of each of the individual carriages drives the carriage along the conveyor rail.

Abstract: The invention is a conveyor assembly (10) having a vehicle (12) which moves about a track (18). The track (18) includes rails (20) extending therealong for supplying power and command signals to the vehicle (12). The rails (20) are separated into isolated sections separated by buffers (24) with each section supplying electrical signals. The vehicle (12) includes at least two contacting pads (32, 33) for contacting a rail (20) and conducting the electrical signal on the rail (20) to the vehicle (12). The contracting pads are spaced a distance such that at least one contacting pad (32, 33) is in electrical connection with the rail (20) so that the vehicle (12) continuously receives the electrical signals. The receiver (34) of the vehicle (12) receives the signals from both contacting pads (32, 33) and combines the signals while preventing back feeding to the other contact pad (32, 33).

Abstract: The present invention comprises two control lines parallel to a rail for guiding self-propelling moving bodies. These lines are divided into sections in staggered relationship between which portions of conductor are placed. Sliding contacts, connected to the moving body, travel over the control lines to detect the state of voltage of one and to short circuit the other. A relay reverses the detection and the short circuit on passage of the sliding contacts on each of the portions of conductor. The invention is applicable to the field of handling.