| 摘要 |
A sway stabilizing system is provided for stabilizing sway of a grappler suspended by vertically movable hoisting cables on a gantry crane. The crane is a type which is particularly useful for lifting a standard container from a standard-height chassis, such as a standard road trailer. According to the invention, the system is designed to optimally dampen sway when the grappler is slightly higher than the top of a standard container resting on a standard chassis. More particularly, in order to cancel pendulum sway effect, the sway stabilizing system provides first and second anti-sway cables which are operably guided from the grappler to an overhead trolley of the crane in a longitudinally diagonal manner. The anti-sway cables are acted upon by respective hydraulic cylinder assemblies mounted on the grappler to apply appropriate tension in the respective anti-sway cables. The cylinder assemblies act in opposite directions to dampen grappler sway in both directions along a longitudinal axis. So that the length of the anti-sway cables is adjusted accordingly with the vertical lifting movement of the grappler, the hoisting cables and anti-sway cables are paid out by respective rotatable drums which are rotatably coupled with each other in a constant drive ratio. The geometry of the guided anti-sway cables results in a nonlinear payout rate relative to the vertical lifting rate of the grappler, resulting in payout "error" in the lengths of the anti-sway cables both above and below a design optimization point at which the payout error is zero. The error is compensated by appropriately extending or retracting the respective hydraulic cylinders. The drum drive ratio and a neutral position of the hydraulic cylinders are designed such that the payout error of the anti-sway cables is about zero when the grappler is about one foot higher than a height of the standard shipping container on top of a standard chassis.
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