Walt Disney Productions

Kenneth H Ball

Arthur L Cole, Jr

A collision avoidance system adapted for railroad use comprising a track having connected thereto a plurality of first signal transmitters exciting the track by a first control signal within a first frequency bandpass range and a plurality of second signal transmitters interspaced between the first signal transmitters in an alternating arrangement, such second transmitters exciting the track by a second control signal within a second frequency bandpass range. While the first and second control signals are respectively within the first and second bandpass range, individual ones thereof are separated by frequency increments from the other control signals within the corresponding bandpass range such that any beats therebetween are of a relatively high frequency. A train riding the track includes a front and rear pickup selectively connected to a dual frequency amplifier across a two-position switch where the amplifier, at its output, connects to a first and second bandpass filter respectively centered at the first and second frequency bandpass. The outputs of the respective filters are rectified and fed to corresponding comparators wherein the signals are compared against a preselected level. The outputs of the comparators are then combined in a logical AND circuit which, across a delay network having a long time constant in the direction of brake engagement and a short time constant in the direction of brake disengagement, operates the brakes of the train. Included also in the train, intermediate the front and rear pickups, is a shunt circuit including the motor of the train, whereby the control signals are attenuated. Thus, the next succeeding train will not receive the shunted control signals and will therefore engage the brakes.

Collision avoidance system

A guidance system for controlling the path of a boat comprising a first conductor disposed below the surface of water in a first elongated loop and connecting at the terminals thereof across an A.C. source of electrical signal and a second conductor driven in a quadrature with the first conductor and disposed in a second loop partly superposed over the first loop. A first and second orthogonal inductive coil, mounted in the boat along a plane parallel to the loop and a plane normal to the loop plane and substantially parallel to the centerline thereof sense the vertical and horizontal components of the electromagnetic field generated about the conductor loops to produce corresponding induced signals respectively varying in amplitude and phase according to the amplitude of the electromagnetic field and the position thereof. Such induced signal of the first and second coils are then clipped by signal limiters and connected to a common phase detector to produce a phase angle signal indicative of the amplitude of deviation of the coils relative the loops. The phase detector output signal is then connected to control a steering apparatus.

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Tarzana, CA, United States of America

Kenneth H Ball