Deep foundation excavator

Patent metadata

Field	Value
Publication number	US-12435486-B2
Application number	US-202117633979-A
Country	US
Kind code	B2
Filing date	Mar 9, 2021
Priority date	Mar 31, 2020
Publication date	Oct 7, 2025
Grant date	Oct 7, 2025

Abstract

A bucket raising/lowering and opening/closing device ( 11 ) of a deep foundation excavator ( 1 ) includes a raising/lowering cylinder ( 12 ), a first raising/lowering sheave ( 14 ) and a first opening/closing sheave ( 15 ) that move in an expansion/contraction direction of the raising/lowering cylinder ( 12 ), a second raising/lowering sheave ( 17 ), a second opening/closing sheave ( 20 ), an opening/closing cylinder ( 18 ) that moves the second opening/closing sheave ( 20 ) to be closer to and to be separated from the first opening/closing sheave ( 15 ), a raising/lowering rope ( 24 ) that is wound around the first raising/lowering sheave ( 14 ) and the second raising/lowering sheave ( 17 ), and an opening/closing rope ( 25 ) that is wound around the first opening/closing sheave ( 15 ) and the second opening/closing sheave ( 20 ). In addition, provided are a slack adjustment cylinder ( 26 ) that expands and contracts to adjust the slack of the opening/closing rope ( 25 ), and a slack adjustment sheave ( 28 ) that moves in a direction of being closer to and being separated from the second opening/closing sheave ( 20 ) in response to an expansion/contraction movement of the slack adjustment cylinder ( 26 ).

First claim

The invention claimed is:

1. A deep foundation excavator comprising:
an automotive vehicle body; and
a working mechanism disposed in the vehicle body,
wherein the working mechanism includes:
a boom disposed in the vehicle body;
an arm disposed in a tip end of the boom;
a bucket raising/lowering and opening/closing device disposed in the arm; and
a clamshell bucket that is disposed to be capable of raising and lowering to the arm and excavates a vertical shaft by a raising/lowering movement and an opening/closing movement of the bucket raising/lowering and opening/closing device,
wherein the bucket raising/lowering and opening/closing device includes:
a raising/lowering cylinder disposed in the arm;
a first raising/lowering sheave and a first opening/closing sheave that are attached to one end side of the raising/lowering cylinder and move in an expansion/contraction direction of the raising/lowering cylinder;
a second raising/lowering sheave that is disposed in the arm to be separated from the first raising/lowering sheave in the expansion/contraction direction of the raising/lowering cylinder;
a second opening/closing sheave that is disposed in the arm to be separated from the first opening/closing sheave in the expansion/contraction direction of the raising/lowering cylinder;
an opening/closing cylinder that is disposed in the arm and moves the second opening/closing sheave to be closer to and to be separated from the first opening/closing sheave;
a raising/lowering rope having one end in a length direction attached to the arm, the other end attached to the clamshell bucket and an intermediate portion wound around the first raising/lowering sheave and the second raising/lowering sheave; and
an opening/closing rope having one end in a length direction attached to the arm, the other end attached to the clamshell bucket and an intermediate portion wound around the first opening/closing sheave and the second opening/closing sheave,
wherein the bucket raising/lowering and opening/closing device further includes:
a slack adjustment cylinder that is disposed in the arm and expands and contracts for adjusting the slack of the opening/closing rope; and
a slack adjustment sheave around which an intermediate portion of the opening/closing rope is wound in a state of being attached on one end of the slack adjustment cylinder and that moves in a direction of being closer to and being separated from the second opening/closing sheave in response to an expansion/contraction movement of the slack adjustment cylinder, and
wherein the bucket raising/lowering and opening/closing device further includes:
an opening/closing operation tool configured to operate the opening/closing cylinder;
a raising/lowering operation tool configured to operate the raising/lowering cylinder;
a detector configured to detect whether or not a tension acting on the opening/closing rope is equal to or less than a predetermined value;
a cylinder switching valve configured to switch an operation target of the opening/closing operation tool from the opening/closing cylinder to the slack adjustment cylinder when the detector detects that the tension acting on the opening/closing rope is equal to or less than the predetermined value; and
a cylinder contraction device configured to contract the slack adjustment cylinder when the raising/lowering operation tool is operated to a raising side to raise the clamshell bucket.

2. The deep foundation excavator according to claim 1 ,
wherein the cylinder contraction device includes a throttle for restricting a contraction speed of the slack adjustment cylinder.

3. The deep foundation excavator according to claim 1 ,
wherein the cylinder contraction device includes:
a discharge liquid line for connection between a bottom-side oil chamber in the slack adjustment cylinder and a hydraulic oil tank; and
a pilot operation check valve that is disposed in the discharge liquid line and allows hydraulic oil in the bottom-side oil chamber to flow toward the hydraulic oil tank when the raising/lowering operation tool is operated to the raising side to raise the clamshell bucket.

4. The deep foundation excavator according to claim 1 ,
wherein the cylinder contraction device includes:
a forced switch pilot line configured to switch a slack removal switching valve so that hydraulic oil is supplied to a rod-side oil chamber in the slack adjustment cylinder when the raising/lowering operation tool is operated to the raising side to raise the clamshell bucket.

5. The deep foundation excavator according to claim 1 ,
wherein the raising/lowering cylinder, the opening/closing cylinder and the slack adjustment cylinder each are arranged along a longitudinal direction of the arm.

Assignees

• Hitachi Construction Mach Co

Inventors

• Isogai Kasumi
• Inamoto Akira
• Itou Minoru
• Seki Seiji

Classifications

• E02F3/4135

  with grabs mounted directly on a boom · CPC title

• E02F3/47 Primary

  with grab buckets (grab equipment for cranes B66C) · CPC title

• E02F9/14

  Booms {only for booms with cable suspension arrangements (for booms or manipulators with cable suspensions for suction pipes E02F3/905 takes precedence; for booms per se E02F3/38; E02F3/34 for bucket-arms)}; Cable suspensions · CPC title

• E02F3/475

  for making foundation slots (slotting machines with a pair of digging wheels E02F3/205) · CPC title

• E02F9/2296

  Systems with a variable displacement pump · CPC title