초록 ▼

A lift truck (16) carries a leftwardly directed ultrasonic receiver (32L) and a rightwardly directed ultrasonic receiver (32R) and an RF transmitter (34). Upon depositing its load in an assigned bin in a warehouse (FIG. 1), a load sensor (22) is actuated to cause transmission of a coded signal as to

A lift truck (16) carries a leftwardly directed ultrasonic receiver (32L) and a rightwardly directed ultrasonic receiver (32R) and an RF transmitter (34). Upon depositing its load in an assigned bin in a warehouse (FIG. 1), a load sensor (22) is actuated to cause transmission of a coded signal as to lift height and vehicle identification to a central station (60). This initiates a vehicle search by energizing ultrasonic transmitters (42-52). The ultrasonic receivers (32L and 32R) on a vehicle in a path under surveillance detect the sonic signal and relay this to the central station by way of the RF transmitter (34). The time duration which elapsed from energization of the ultrasonic transmitter to detection of the sonic signal is used to measure vehicle path depth and a comparison of the magnitudes of the sonic signals received by the receivers (32L and 32R) indicates the heading direction of the vehicle.

대표청구항 ▼

A system for detecting path position of a vehicle adapted to travel along a path to an assigned location along said path, comprising: first transmitter means for transmitting a first signal along said path when the position of said vehicle is to be determined; first receiver means carried by said ve

A system for detecting path position of a vehicle adapted to travel along a path to an assigned location along said path, comprising: first transmitter means for transmitting a first signal along said path when the position of said vehicle is to be determined; first receiver means carried by said vehicle for receiving a said first signal; second transmiter means carried by said vehicle for transmitting a second signal along said path upon receipt of said first signal by said first receiver means; second receiver means associated with said first transmitter means for receiving said second signal; at least one of said first and second transmitter means including means for transmitting a sonic signal, whereby at least one of said first and second signals comprises a sonic signal; means for determining the position of said vehicle along said path upon the basis of the time interval between transmission and reception of said sonic signal; and, said vehicle further carries means for providing an indication that the position of said vehicle is to be determined, and for causing said second transmitter means to transmit a third signal in response to said indication, and wherein said first transmitter menas is actuated to transmit said first signal when said third signal is received by said second receiving means.