Storage and retrieval apparatus

Claim 1

A material handling apparatus for moving loads between load support means that form a dock area or home station and a plurality of storage areas arranged in horizontal and vertical rows, comprising: a load transfer unit movable horizontally and vertically along a path adjacent said storage areas and dock area and including a horizontally movable trolley assembly, a first member carried by said trolley assembly to support a load, means supporting said first member to provide movement thereof laterally of the path of the load transfer unit and vertically to effect load transfer between the said member and said load support means of the storage area or dock area, drive means to move said trolley assembly and load transfer unit and first member along said path adjacent said areas and means to move said first member laterally of the path, two vertically spaced fluid motors having relatively reciprocating piston and cylinder elements carried by said trolley assembly and a cable extending from the means supporting said first member secured to a reciprocating element of one of said fluid motors and extending about a Rotary member connected to a reciprocating element of the other of said fluid motors, one of said fluid motors operable to move the supporting means for said first member vertically between load support means and the other serving as an auxiliary drive motor operable to move the first member an incremental distance vertically relative to said trolley assembly to effect a load transfer, and means to control the movement and operation of the load transfer unit independently of external commands once the unit leaves the dock area, said means consisting of electrical circuit means operable to control movement of said first member vertically and horizontally concurrently, to control movement of said first member laterally, and to render said drive means for said unit and first member inoperable when the first member is moved laterally of the path of the load transfer unit, said control means including first means presettable prior to movement of the unit from the first area to control the drive means to move said transfer unit and first member from the dock area to a position adjacent a first preselected storage area and to move said first member laterally of the path to a first position in the first preselected storage area in alignment with load support means and to subsequently effect a load transfer therebetween, second means presettable prior to movement of the unit from the first area to control the drive means subsequent to said load transfer to move the first member directly from said first preselected storage area to a second storage area in alignment with load support means thereof regardless of the locations of said first and second storage areas and to effect a load transfer at said second storage area, said first and second presettable control means including first counter means for counting said vertical rows of storage areas and controlling the drive means to position said transfer unit at the vertical rows of first and second preselected areas, second counter means for counting said horizontal rows of storage areas and controlling the drive means to position said first member at first and second preselected storage areas, and means to change the speed at which the transfer unit is moved from a high speed to a lower speed operation in response to the counting of a predetermined number of storage areas, sensing means carried by said load transfer unit for detecting changes in the vertical location and horizontal location of the first member to actuate said counter means controlling the operation of said motor means, and said control means further including means for determining the direction of movement required to move said load carrier from the first preselected storage area to the second and controlling said drive means to accomplish the required direction of movement, said means for determining the required direction of movement of said load carrier and for controlling said drive means including two directiondetermining switch means, one for controlling the direction of horizontal trolley assembly movement and one for controlling the direction of vertical load carrier movement, the condition of which switch means is individually varied in response to movement of the transfer unit past the position of the second preselected storage area, in a horizontal or vertical direction, or both, as it travels to the first preselected storage area, and which conditions individually determine whether the horizontal or vertical directions of travel, or both, are reversed to move the load carrier to the second storage area and control such reversal.