Stacker crane for narrow aisles

A stacker crane comprising a mast extending along a vertical axis, transport means supporting the mast for horizontal motion, and load supporting means positionable vertically along the mast, said transport means comprising an elevated trolley having a turntable thereon to which the mast is connected for rotation about said axis, and wherein a winch on said turntable, connected with the load supporting means by a cable, positions the load supporting means vertically along the mast, said stacker crane characterized by:

• A. the mast having a short tubular upper portion concentric to said axis and connected to the turntable, through which said cable extends;
• B. the mast comprising a pair of vertically extending mast elements that are spaced to opposite sides of said axis,
• (1) each of said mast elements having at its upper end a rigid connection to a transversely extending beam secured to said tubular upper portion;
• C. the masts being connected with said transport means for rotation about said axis;
• D. the load supporting means comprising a carriage member, said carriage member
• (1) being of inverted U-shaped with a pair of vertically extending legs connected at their upper ends by a sidewardly extending bight portion,
• (a) said cable having a connection to the bight portion of the carriage member,
• (2) being disposed between the mast elements with each of its legs guidingly engaging one of them, and
• (3) having a pair of horizontally extending parallel and opposite tracks, one on each leg,
• (a) each projecting in both a forward and a rearward direction beyond its leg, and
• (b) each defining a pair of opposite track surfaces that extend along at least a major portion of its length,
• (i) one of which faces upwardly and
• (ii) the other of which faces downwardly,
• (c) each of said tracks having a groove therein which opens towards the other track and which defines said surfaces;
• E. the load supporting means further comprising
• (b 1) a frame confined between the tracks,
• (2) a pair of load engaging tongues projecting forwardly beyond said frame,
• (a) said tongues being mounted on said frame for translatory sideward motion,
• (3) two pairs of rollers on said frame, one pair for each of said tracks,
• (a) a front roller of each pair being rollingly engaged with said upwardly facing surface on its track,
• (b) the rear roller of each pair being rollingly engaged with said downwardly facing surface on its track, and
• (c) all of said rollers having their axes substantially contained in a single horizontal plane;
• F. actuating means carried by the frame and connected with each of the tongues for adjustingly moving the tongues sidewardly towards and from one another;
• and
• G. means on said frame for reversibly rotatably driving one roller of each of said pairs, for moving the frame along said tracks to an extended forward position in which said tongues project beyond the front ends of said tracks and to a retracted rearward position in which said tongues are near said axis.