Device for indicating a certain proximity between movable units

Claim 1

An apparatus for indicating a certain proximity between movable vehicles having a control device assuring that the vehicles automatically follow a predetermined path determined by electrical control loops fed with an alternating current, said apparatus comprising a device for transmitting by means of said electrical control loops to said vehicles an electro-magnetic synchronizing signal in the form of synchronizing pulses propagated with very high speed, a first receiver device, and a transmitter device, situated on each of said vehicles for receiving the synchronizing pulses and for activating said transmitter devices to emit an information signal in the form of wave propagation movement in the air with a considerably lower speed of propagation in comparison with the synchronizing signal, said information signal being in the form of information pulses emitted in synchronism with the reception of the synchronizing pulses, devices situated on each of said vehicles, including a second receiver for receiving the information pulses, means for measuring a time difference arising between the synchronizing pulses as received by a vehicle and the received information pulses emitted synchronously from another vehicle, means for comparing said time difference with a predetermined time value corresponding to a certain proximity between the vehicles, and means for emitting a proximity indicating signal, when said time difference falls below said time value, thereby indicating that the distance between two vehicles lies below a predetermined distance value, said synchronizing pulses reaching all vehicles substantially simultaneously, resulting in that all vehicles transmit during their travel along the path information signals substantially in synchronism with each other and that said proximity indicating signal is caused to be emitted in each individual vehicle, as soon as the same comes within said certain proximity of any other vehicle.

Claim 2

An apparatus for indicating a certain proximity between movable vehicles having a control device assuring that the vehicles automatically follow a predetermined path determined by electrical control loops fed with an alternating current, said apparatus comprising a device for transmitting by means of said electrical control loops to said vehicles an electro-magnetic synchronizing signal in the form of synchronizing pulses propagated with very high speed, a first receiver device, and a transmitter device, situated on each of said vehicles for receiving the synchronizing pulses and for activating said transmitter devices to emit an information signal in the form of wave propagation movement in the air with a considerably lower speed of propagation in comparison with the synchronizing signal, said information signal being in the form of information pulses emitted in synchronism with the reception of the synchronizing pulses, devices situated on each of said vehicles, including a second receiver for receiving the information pulses, means for measuring a time difference arising between the synchronizing pulses as received by a vehicle and the received information pulses emitted synchronously from another vehicle, means for comparing said time difference with a predetermined time value corresponding to a certain proximity between the vehicles, and means for emitting a proximity indicating signal, when said time difference falls below said time value, thereby indicating that the distance between two vehicles lies below a predetermined distance value, said synchronizing pulses reaching all vehicles substantially simultaneously, resulting in that all vehicles transmit during their travel along the path information signals substantially in synchronism with each other and that said proximity indicating signal is caused to be emitted in each individual vehicle, as soon as the same comes within said certain proximity of any other vehicle.