Abstract: A hydraulic system for actuating opposed arms of a grappler for a gantry crane dampens swaying motion of the arms. Within a conduit which carries pressurized fluid to and/or from actuators to pivot the arms, a dampener includes a restrictor having an orifice to restrict the flow in at least one direction. Each of the dampeners can include a respective check valve to permit free flow through one direction of the conduit and to direct reverse flow through the orifice. In a specific embodiment, a load is received between opposed arms of the grappler to seat upon shoes which extend inwardly from the arms. To urge the shoes to remain in secure lifting contact under the load, flow is restricted when the swaying load moves the arm outwardly, permit free motion of the arm when the swaying motion pulls the arm inwardly.

Abstract: A swing arm style grappler for a gantry crane is equipped with contact shoes configured to engage in horizontal, flush contact at the underside of a standard load. The grappler includes a plurality of pivotable arms movable between an unclamped position, wherein the arms are positioned outwardly free from the load, and a clamped position wherein the arms are positioned inwardly to clamp the load. Each of the arms has an elongate portion, one of the shoes being mounted to a lower end of the elongate portion. The shoe includes a lifting shelf which projects generally inwardly at an angle such that, when the arms are in the clamped position, the shelf is horizontal.

Abstract: A gantry crane including a lifting grappler is provided with a hoist locking mechanism to prevent undesired downward drifting of the grappler, especially during periods when the crane is parked and not in operation. The hoist locking device can selectively secure the grappler in a raised position, maintaining a maximum clearance under the raised grappler. The crane includes a hoist line, such as a chain or cable, that suspendably supports the weight of the grappler, and a hoist actuator for moving the hoist line, thereby lifting or lowering the grappler. In an embodiment, the hoist locking device is selectively operable to secure the hoist line in a predetermined position, preventing the grappler from lowering. For example, an embodiment of the hoist locking device includes a hook-shaped latch member movably mounted to the frame for engagement with a catch member fixed relative to the hoist line. The catch member may, for example, be a projection from a clevis mounted to the hoist actuator.

Abstract: A gantry crane is provided which is equipped with standard wheels having rubber tires for free maneuverability on a road surface, such as asphalt, gravel, pavement, etc., wherein the crane is additionally equipped with a plurality of railwheels to provide auxiliary support one or more rails in the loading area. In a first mode, the crane is supported only on rubber tires for driving on a paved surface, and in other modes, one or both sides of the crane are supported via the railwheels on rails. In an embodiment, a railwheel may be securely mounted coaxially to the steel rim of the respective steel wheels, forming a dual or combination wheel. The railwheels are sized relative to the tires of the standard wheels so that the railwheel does not impair non-rail loading operations, i.e., the railwheel vertically clears the ground even when the tires deflect as the crane is fully loaded. Railwheels may be provided on one or both sides of the crane.

Abstract: A steering apparatus and method are provided for a gantry crane with four corner-mounted wheel assemblies having steerable wheels. The crane is a type which drivable in either longitudinal or transverse directions, wherein steering control is automatically switched steering control to the “leading” wheels, or more particularly the wheels of the “leading” pair of wheel assemblies. The system detects which two of the wheel assemblies are leading, whether the crane is moving longitudinally frontwardly or rearwardly, or transversly rightward or leftward. The system includes a steering controller which controls steering actuators in such a manner that the wheels of the then-leading wheel assemblies are moved according to steering control input, while the wheels of a remaining pair of then-“trailing” wheel assemblies are moved to and/or held in, a straight alignment.

Abstract: A gantry crane is provided which is equipped with standard wheels having rubber tires for free maneuverability on a road surface, such as asphalt, gravel, pavement, etc., wherein the crane is additionally equipped with a plurality of railwheels to provide auxiliary support one or more rails in the loading area. In a first mode, the crane is supported only on rubber tires for driving on a paved surface, and in other modes, one or both sides of the crane are supported via the railwheels on rails. In an embodiment, a railwheel may be securely mounted coaxially to the steel rim of the respective steel wheels, forming a dual or combination wheel. The railwheels are sized relative to the tires of the standard wheels so that the railwheel does not impair non-rail loading operations, i.e., the railwheel vertically clears the ground even when the tires deflect as the crane is fully loaded. Railwheels may be provided on one or both sides of the crane.

Abstract: An integral coupling is provided for transmitting torque from a flexible driveplate mounted to an engine flywheel. The coupling has a base portion which is fixed to the flexible driveplate and a shaft portion which extends axially away from the base portion. The shaft portion has male splines which are shaped to be matably received in a female splined connector of a rotatable member. In particular, the female splined connector is formed in the hub of a gearbox input pinion driving a gearbox which, in turn, drives a hydraulic pump supplying hydraulic pressure to systems of a gantry crane. The integral coupling permits axial movement at the male splined end which is distally located relative to the flexible driveplate. The integral coupling provides improved performance over a conventional two-piece coupling having a male--male splined shaft which matably fit the base portion mounted to the flexible driveplate.

Abstract: In a hydraulic cylinder actuation system for a crane having a conventionally charged main hydraulic pump, a supplemental pump or "charge boost" pump is provided. To efficiently achieve fast actuation speeds of the cylinder, the charge boost pump provides supplemental charge flow in response to a need in the system. The charge boost pump is driven independently from the main pump or may be driven by the main pump if the main pump is equipped with drive thru capability to provide a variable output and preferably includes a load sensing means for controlling the output.

Abstract: A hoist assembly is provided for an overhead crane adapted for pivoting wide panels and the like between horizontal and vertical positions. The hoist assembly is supported on an elevated horizontal beam and includes a main trolley, supporting a main lifting cable, and an auxiliary trolley, supporting an auxiliary lifting cable. The main trolley is mounted for positively drivable movement along the horizontal beam, while the auxiliary trolley is freely slidable along the horizontal beam. The freely slidable auxiliary trolley automatically moves along the beam in response to a horizontal force component of cable tension when a load is being pivoted, so that the auxiliary trolley maintains a substantially vertical position over its lifting point on the load. A method for pivoting a load with the hoist assembly is also provided.