Patent ID: 7793794

Claim:
A hoist for a low space crane comprising: a hoist frame having a wire drum; first and second support plates attached to the wire drum and forming a structure of the hoist frame; a girder having a rectangular cross-section wherein the rectangular cross-section is formed of first and second horizontal surfaces and first and second vertical surfaces; a guide rail mounted vertically above the first vertical surface of the girder such that an impact load applied to the guide rail is distributed on the cross sectional area of the first vertical surface of the girder; and first and second equal distribution units, wherein the first and second support plates are respectively mounted on the first and second equal distribution units, wherein each equal distribution unit has first and second load support rollers mounted above the guide rail and is configured to move the hoist frame along a length of the guide rail such that an impact load applied to the hoist frame is distributed on the guide rail and the cross sectional area of the first vertical surface of the girder, wherein said first and second equal distribution units comprise: first and second support pins which are fixed at lower sides of the first and second support plates; and first and second load support wheel parts which are mounted on the guide rail and move along the guide rail, with lower sides of the first and second support pins being mounted thereon and being roll-contact with the guide rail, wherein said first and second load support wheel parts comprise: first and second bodies which have first and second insertion grooves at the center portions of the first and second bodies for mounting the first and second support plates thereon, and first and second spherical grooves formed in lower sides of the first and second insertion grooves so that the first and second contact parts of the first and second support pins roll-contact with the first and second spherical grooves; and wherein the first and second load support rollers are engaged with the first and second bodies and are mounted on the guide rail and run along the guide rail, wherein the hoist further comprises: first and second support bolts which are engaged with the first and second bodies, and of which the ends are supported by the first and second support plates, so that a constant interval is maintained between the first and second insertion grooves and the first and second support plates.