Slant-truss crane rail

An overhead crane, comprising:

• first and second runway rails that extend parallel to a generally horizontal runway axis;
• a bridge that extends along a bridge axis that is generally horizontal and perpendicular to the runway axis and that is movable on the runway rails along the runway axis, wherein the bridge includes first and second bridge rail that are connected to each other and that are generally parallel, wherein each bridge rail has first and second ends and rolling structures at the first and second ends which are rollably supported on the first and second runway rails;
• a trolley that is rollably supported on the first and second bridge rails;
• and
• a lifting device for holding a load, wherein the lifting device is supported by the trolley and is capable of lifting loads in such a way as to generate downward forces that are offset laterally from the bridge axis,
• wherein, for each bridge rail, the bridge further includes
• a single first bridge reinforcement member supporting the bridge rail and extending substantially upwardly from the longitudinal center of the bridge rail, the first bridge reinforcement member having a lower end mechanically connected to the bridge rail, and an upper end, the first bridge reinforcement member loaded under tension,
• a single pair of second bridge reinforcement members also supporting the bridge rail and extending between the upper end of the first bridge reinforcement member and mechanically connected to the bridge rail proximate the first and second outer ends, the second bridge reinforcement members loaded in compression, and
• the bridge reinforcement members providing the greatest increase in bending strength at the longitudinal center of the bridge rail,
• wherein the first bridge reinforcement member has first and second opposed first member receiving apertures at the upper end, and wherein the bridge rail further includes first and second brackets positioned respectively at the first and second outer ends of the bridge rail, each bracket having a bracket receiving aperture that generally faces one of the first member receiving apertures, and wherein each second bridge reinforcement member has a first end that extends into one of the first member receiving apertures and a second end that extends into the bracket receiving aperture on one of the brackets, and
• wherein the first end of each second bridge reinforcement member is retained within the first end receiving aperture by a first end retaining pin, and the second end of each second bridge reinforcement member is retained within the second end receiving aperture by a second end retaining pin.

A retrofit kit for strengthening an overhead crane, wherein the overhead crane includes first and second runway rails that extend parallel to a generally horizontal runway axis, a bridge that extends along a bridge axis that is generally horizontal and perpendicular to the runway axis and that is movable on the runway rails along the runway axis, wherein the bridge includes a bridge rail having first and second ends and rolling structures at the first and second ends which are rollably supported on the first and second runway rails, a trolley having a plurality of trolley wheels thereon permitting movement of the trolley along the bridge rail, and a lifting device for holding a load, wherein the lifting device is supported by the trolley, wherein the bridge rail includes a pair of track flanges which form a track for a trolley and wherein the bridge rail further includes a second pair of flanges, wherein the retrofit kit includes:

• a single first bridge reinforcement member supporting the bridge rail and extending upwardly substantially from the longitudinal center of the bridge rail, the first bridge reinforcement member having a lower end mechanically connected to the bridge rail, and an upper end, the first bridge reinforcement member loaded under tension,
• a single pair of second bridge reinforcement members also supporting the bridge rail and extending between the upper end of the first bridge reinforcement member and mechanically connected to the bridge rail proximate the first and second outer ends, the second bridge reinforcement members loaded in compression, and
• the bridge reinforcement members providing the greatest increase in bending strength at the longitudinal center of the bridge rail,
• wherein the first bridge reinforcement member is the only first bridge reinforcement member on the bridge rail and wherein the two second bridge reinforcement members are the only two second bridge reinforcement members on the bridge rail, and
• wherein at least one fastener passes through each of the first bridge reinforcement member and the brackets and into an associated clamping plate to clamp the second flanges.