| 摘要 |
A single-line clamshell bucket is provided comprising an upper sheave housing and an upper sheave assembly connected to the upper sheave housing. The bucket also comprises a lower sheave assembly vertically aligned beneath the upper sheave assembly in a manner such that a cable reeved between the lower sheave assembly and the upper sheave assembly will draw the upper sheave assembly and the lower sheave assembly together when the cable is pulled upward. The bucket further has a plurality of bucket segments and a plurality of arms, each of the arms having an end pivotally connected to the upper sheave housing and another end pivotally connected to one of the bucket segments. A lower block assembly is pivotally linked with the bucket segments in a manner such that vertical movement of the lower block assembly in relation to the upper sheave housing opens and closes the bucket segments. The bucket includes a connector device for mechanically connecting the lower sheave assembly and the lower block assembly when the bucket segments are supporting the weight of the clamshell bucket. Finally, the bucket includes a damping assembly comprising a first lever arm, having a first and second end, rigidly attached at the first end to the lower block assembly. The damping assembly also includes a second lever arm, having a first and second end, rigidly attached at the first end to a bucket segment in a manner such that a force acting on the second end of the second lever arm will cause the bucket segments to pivot. The damping assembly further has a damping element including: a cylinder and a ram forming a hydraulic cylinder and ram assembly, pivotally mounted at one end to the second end of the first lever arm and pivotally mounted at an opposite end to the second end of the second lever arm; a hydraulic fluid reservoir, in fluid connection with the cylinder, and a hydraulic fluid flow control device, connected between the cylinder and the hydraulic fluid reservoir, for restricting the rate of flow of hydraulic fluid from the cylinder into the hydraulic fluid reservoir when the ram is urged in a predetermined direction within the cylinder.
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