Sway control arrangement for hoist systems

A mobile gantry crane comprising:

• frame means;
• a vertically movable load lifting structure;
• hoist means including cables for suspending and raising and lowering said lifting structure and a load connected thereto;
• means for controlling sway of said suspended load including sway control cable means connected to said lifting structure;
• means for reeling and unreeling said sway control cable means;
• means for supplying pressurized hydraulic fluid;
• stabilizing hydraulic motor means adapted to receive pressurized fluid from said fluid supplying means for driving said reeling means to reel said sway control cable means during pressurized hydraulic fluid flow through said motor means in a first direction, said motor means being adapted to hydraulically dampen and control sway of said suspended load by receiving restricted reverse fluid flow therethrough in a second direction during unreeling of said sway control cable means;
• reverse fluid flow circuit means adapted to communicate between a fluid inlet and a fluid outlet of said stabilizing hydraulic motor means for permitting reverse flow therethrough, said circuit means including flow restricting means for restricting said reverse fluid flow through said stabilizing hydraulic motor means to hydraulically dampen and control sway of said suspended load, and one-way valve means disposed in series flow relation with said flow restricting means, said one-way valve means being adapted to open for reverse fluid flow through said circuit means in response to fluid pressurization greater than the pressure of fluid from said source;
• and means to prevent reverse flow of hydraulic fluid to said source of pressurized fluid.