| 摘要 |
A presence detector for use with a mobile storage system including at least a first movable storage unit with a prime mover adapted to move the shelving unit along a path of movement, and at least one blocking object, such as a second movable storage unit, a stationary storage unit or a wall, positioned on the path. The presence detector detects the presence of an obstacle in the path of movement and discontinues movement of the first unit while the obstacle is in the path of movement. The presence detector includes at least one light source mounted to either the first unit or the blocking object so as to provide light into the path of movement. At least one light detector is mounted to the blocking object or first unit, respectively, opposite the light source. A control unit is connected to the light detector and receives a signal from the light detector, that signal indicating whether or not the light detector is receiving light from the light source. The control unit disables the prime mover from moving the first storage unit along the path when the signal is received from the light detector indicating that light is not being received from the light source. The control unit includes the capability to determine which of several detectors was last screened, so that the prime mover is not re-enabled if the last detector screened was more than a predetermined distance from the end of the aisle. |
