| 摘要 |
A forklift mast assembly for attachment to a self propelled vehicle includes a pair of outer masts horizontally spaced from each other, and a pair of inner masts disposed just inwardly of the outer masts for up and down rolling motion relative to the same. Each outer mast is of U shaped cross section, defining a space opening inwardly or toward the other outer member for rotatably receiving an inner roll on the bottom end of the associated inner mast. Each inner mast is of H shaped cross section, defining an outwardly open space for rotatably receiving an outer roll on the top end of the associated outer mast, and an inwardly open space for rotatably receiving one pair of carrier rolls on a prong carrier. The outer masts are further rimmed to bear the axial thrust of inner rolls when the prong carrier is loaded out of the perpendicular in the plane of the mast assembly. Preferably, the inner masts are also rimmed to bear against the outer rolls and, if desired, against the carrier rolls as well. The improved mast configurations make it possible to eliminate a tie at least from between the bottom ends of the inner masts. Ties may also be removed from between the top ends of the outer masts and from between the top ends of the inner masts, depending upon the arrangement of the other parts of the mast assembly. |
