Load extending mechanism for material handling vehicle

Claim 2

Material handling apparatus for handling a load including a platform rotatable about a vertical axis, a load supporting shuttle mounted on said platform for extension and retraction relative thereto, first drive means operable to extend and retract said shuttle, a secondary load supporting member mounted on said shuttle for extention and retraction relative to said shuttle, and second drive means operable to extend and retract said secondary load supporting member, said first and second drive means being interconnected for simultaneous operation and said second drive means including a lost motion connection with said secondary load supporting member, whereby initial extension of said secondary load supporting member relative to said shuttle lags extension of said shuttle by a predetermined travel distance and full retraction of said shuttle lags full retraction of said secondary load supporting member by a predetermined travel distance whereby said load, shuttle and secondary member are shiftable from a fully retracted position to a position which allows them to rotate within a minimum swing radius.

Claim 3

Apparatus as claimed in claim 1 in which said shuttle comprises at least one extensible and retractable fork and said secondary load supporting member comprises a sheath member partly surrounding said fork.

Claim 4

In a material handling vehicle for handling a load including a platform rotatable about a vertical axis, a carriage projectable and retractable with respect to the platform, at least one load support member mounted on the carriage, an elongated, telescopable extension on the load support member, and means for projecting and retracting the carriage including a drive shaft, the improvement comprising: a. a first pulley wheel mounted on the drive shaft; b. a second pulley wheel mounted adjacent the load support member and oppositely disposed from the carriage; c. a flexible connecting member passing around said first and second pulley wheels, at least a portion of said member extending longitudinally of the extension; d. a first drive member fixedly attached to said flexible connecting member intermediate said first and second pulleys; and e. driven means fixedly attached to the extension, said means defining a first slot adapted to receive said first drive member and maintain engagement therewith during subsequent travel of said flexible connecting member, said first drive member and said slot spaced apart sufficiently, when the carriage is retracted, to permit a selected amount of linear movement of said connecting member and projection of the carriage before said first drive member engages said driven means whereby said load, carriage, load support member and extension are shiftable from a fully retracted position to a position which allows them to rotate within a minimum swing radius.

Claim 5

In a material handling vehicle for handling a load including a platform rotatable about a vertical axis, a carriage projectable and retractable with respect to the platform, at least one load support member mounted on the carriage, an elongated, telescopable extension on the load support member, and means for projecting and retracting the carriage including a drive shaft, the improvement comprising: a. a first pulley wheel mounted on the drive shaft; b. a second pulley wheel mounted adjacent the load support member and oppositely disposed from the carriage; c. a flexible connecting member passing around said first and second pulley wheels, at least a portion of said member extending longitudinally of the extension; d. a first drive member fixedly attached to said flexible connecting member intermediate said first and second pulleys; and e. driven means fixedly attached to the extension, said means defining a first slot adapted to receive said first drive member and maintain engagement therewith during subsequent travel of said flexible connecting member, said first drive member and said slot spaced apart sufficiently, when the carriage is retracted, to permit a selected amount of linear movement of said connecting member and projection of the carriage before said first drive member engages said driven means whereby said load, carriage, load support member and extension are shiftable from a fully retracted position to a position which allows them to rotate within a minimum swing radius.

Claim 6

The improvement of claim 3 wherein said driven means comprises: a. a drive plate attached to the extension, said plate defining said first slot; and b. a third pulley wheel positioned adjacent said drive plate to support said flexible connecting member and, as said first drive member passes around said third pulley wheel, to permit said first drive member to enter said first slot.

Claim 7

The improvement of claim 4 wherein said first, second and third pulley wheels are sprocket wheels and said flexible connecting member is a sprocket chain.

Claim 8

The improvement of claim 4 wherein said drive plate defines a curvilinear second slot, for passage therein of said drive member, said second slot being in open communication with said first slot.

Claim 9

The improvement of claim 6 including a third slot offset from, but in open communication with, said second slot and a second drive member fixedly attached to said flexible connecting member and positioned adjacent said first drive member to be received in said third slot when said first drive member is received in said first slot and said second drive member passes around said third pulley wheel.

Claim 10

The improvement of claim 7 wherein said third slot has a configuration which permits it to maintain engagement with said second drive member, while the carriage is being retracted, until said second drive member passes over said third pulley wheel, disengaging from said third slot and reentering said second slot.