US 12,435,486 B2
Deep foundation excavator
Kasumi Isogai, Omitama (JP); Akira Inamoto, Kashiwa (JP); Minoru Itou, Ushiku (JP); and Seiji Seki, Omitama (JP)
Assigned to HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
Appl. No. 17/633,979
Filed by HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo (JP)
PCT Filed Mar. 9, 2021, PCT No. PCT/JP2021/009328
§ 371(c)(1), (2) Date Feb. 9, 2022,
PCT Pub. No. WO2021/199965, PCT Pub. Date Oct. 7, 2021.
Claims priority of application No. 2020-063331 (JP), filed on Mar. 31, 2020; and application No. 2020-063338 (JP), filed on Mar. 31, 2020.
Prior Publication US 2022/0267984 A1, Aug. 25, 2022
Int. Cl. E02F 3/47 (2006.01); E02F 3/413 (2006.01)
CPC E02F 3/47 (2013.01) [E02F 3/4135 (2013.01)] 5 Claims
OG exemplary drawing
 
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.