Single-line clamshell bucket

A device for damping the forces associated with opening a clamshell bucket while suspended in midair that is mountable in a single-line clamshell bucket having bucket segments pivotally mounted to a lower block assembly in a manner such that the pivotal movement of one of said bucket segments requires the pivotal movement of all other bucket segments, said device comprising:

• a first lever arm, having a first and second end, rigidly attached at said first end to said lower block assembly;
• a second lever arm, having a first and second end, rigidly attached at said first end to a bucket segment in a manner such that a force acting on said second end of said second lever arm will cause said bucket segments to pivot;
• a damping assembly including:
• a cylinder and ram forming a hydraulic cylinder and ram assembly, pivotally mounted at one end to said second end of said first lever arm and pivotally mounted at an opposite end to said second end of said second lever arm;
• a hydraulic fluid reservoir, in fluid connection with said cylinder;
• and a hydraulic fluid flow control device, controllable by an operator and connected between said cylinder and said hydraulic fluid reservoir, for restricting the rate of flow of hydraulic fluid from said cylinder into said hydraulic fluid reservoir when said ram is urged in a predetermined direction within said cylinder.

A single-line clamshell bucket comprising;

• an upper sheave housing;
• an upper sheave assembly connected to said upper sheave housing;
• a lower sheave assembly vertically aligned beneath said upper sheave assembly in a manner such that a cable reeved between said lower sheave assembly and said upper sheave assembly will draw said upper sheave assembly and said lower sheave assembly together when said cable is pulled upward;
• a plurality of bucket segments;
• a plurality of arms, each of said arms having an end pivotally connected to said upper sheave housing and another end pivotally connected to one of said bucket segments;
• a lower block assembly pivotally linked with said bucket segments in a manner such that vertical movement of said lower block assembly in relation to said upper sheave housing opens and closes said bucket segments;
• a guide, in operational connection between said upper sheave housing and said lower block assembly, which suppresses relative movement of said upper sheave housing and said lower block assembly in all directions other than directly toward and away from each other;
• and
• a connector assembly including
• (a) a hook assembly including a hook member pivotally mounted to said clamshell bucket;
• (b) a biasing element connected to said hook assembly in a manner such that said hook member is biased in a first rotational direction but is deflectable in a second rotational direction by a force generated by the weight of said lower sheave assembly;
• (c) a pin assembly having a pin including a first surface for engaging a second surface of said hook member in a manner such that, when said first and second surfaces are engaged, a force acting to separate said lower sheave assembly and said lower block assembly will act to generate a disengaging force against said hook member in said second rotational direction;
• and
• (d) an engagement retaining assembly including a bracket member, a pivoting member pivotally mounted to said bracket member in a manner such that a portion of said pivoting member may operatively contact said hook member when said hook member and pin are engaged, and a hydraulic locking assembly, in mechanical connection with said pivoting member, for locking said pivoting member in a desired position, said hydraulic locking assembly being selectably unlockable by an operator and having sufficient holding strength to resist said disengaging force when locked.

A single line clamshell bucket comprising an upper sheave housing, a plurality of arms, each of said arms being connected at one end to said upper sheave housing and at an opposite end to one of a plurality of bucket segments, said bucket segments being pivotally connected to a lower block, an upper sheave assembly connected to said upper sheave housing, a lower sheave assembly connected by a cable to said upper sheave assembly, and a guide member connecting said lower sheave assembly and said lower block, wherein the improvement comprises:

• (a) a connector assembly to selectively disengage said lower sheave assembly with said lower block, which comprises:
• (i) a hook assembly including a hook member pivotally mounted to said clamshell bucket;
• (ii) a pin assembly having a pin selectively engaging said hook member in a manner such that a force acting to separate said lower sheave assembly and said lower block assembly will act to generate a disengaging force against said hook member;
• (iii) an engagement retaining assembly including a bracket member, a pivoting member pivotally mounted to said bracket member in a manner such that a portion of said pivoting member may operatively contact said hook member when said hook member and pin are engaged, and a hydraulic locking assembly, in mechanical connection with said pivoting member, for locking said pivoting member in a desired position, said hydraulic locking assembly being selectably unlockable by an operator and having sufficient holding strength to resist said disengaging force when locked;
• and
• (b) a bucket damping assembly which comprises:
• (i) a fist lever arm, having a first and second end, rigidly attached at said first end to said lower block assembly;
• (ii) a second lever arm, having a first and second end, rigidly attached at said fist end to a bucket segment in a manner such that a force acting on said second end of said second lever arm will cause said bucket segments to pivot;
• (iii) a damping element including:
• a cylinder and a ram forming a hydraulic cylinder and ram assembly, pivotally mounted at one end to said second end of said first lever arm member not rigidly attached to said lower block assembly and pivotally mounted at an opposite end to said second end of said second lever arm;
• a hydraulic fluid reservoir, in fluid connection with said cylinder;
• and a hydraulic fluid flow control device, connected between said cylinder and said hydraulic fluid reservoir, for restricting the rate of flow of hydraulic fluid from said cylinder into said hydraulic fluid reservoir when said ram is urged in a predetermined direction within said cylinder.