Hydraulic shovel with hoisting hook

• US 6,568,898 B2
• Filed: 05/24/2001
• Issued: 05/27/2003
• Est. Priority Date: 05/26/2000
• Status: Expired due to Fees

• Current Assignee: Komatsu Ltd.
• Original Assignee: Komatsu Ltd.
• Inventors: Nishimura, Satoru, Nagahara, Takumi
• Primary Examiner(s): Underwood, Donald W.
• Application Number:
  US09/865,036
• Publication Number:
  US 20010046433A1
• Time in Patent Office: 733 Days
• Field of Search: 414/694, 414/699, 414/912, 212/250
• US Class Current: 414/699
• CPC Class Codes: E02F 3/964 of several tools mounted on one machine E02F3/962 takes precedence
• CPC Class Codes: Y10S 414/125 Combined or convertible implements

Abstract

A hoisting hook is arranged on a stick boom top pin for attaching a bucket to a distal end of a stick boom and hung at a bucket scooping face side. A bucket fall prevention valve is provided at least on a head side of a bucket cylinder for maintaining the cylinder inner pressure in order to prevent the bucket from free fall. A crane work by the hoisting hook is performed with the bucket dumped to the stick boom back side to the maximum extent. During the crane work, even if the hydraulic oil hose connected to the bottom side of the oil chamber of the hold pressure generation side of the bucket cylinder is broken by an external force, the bucket fall prevention valve acts instantaneously, cuts off the head side oil chamber from the exterior oil passage completely, and maintains the hold pressure of the head side oil chamber, so that the bucket is prevented from rotating suddenly downward. There is provided a hydraulic shovel allowing to perform a good crane work with an improved visibility of an operator, the bucket is prevented from free fall due to the lifted load, by securing the bucket cylinder hold force, and the crane work safety is improved.

Claims

1. A hydraulic shovel, comprising a main boom rising and descending on a revolving frame, a stick boom linked to the distal end of the main boom and swinging in a vertical direction, and a bucket attached to the distal end of the stick boom and swinging similarly in a vertical direction, wherein the main boom, the stick boom and the bucket are respectively operated independently by operation cylinders, stick boom rotation prevention means for preventing the stick boom from free fall by maintaining a bottom side hold pressure is provided on a bottom side of the cylinder for the stick boom, and bucket rotation prevention means for preventing the bucket from free fall by maintaining the bottom side hold pressure when a bucket cylinder is extended is provided at least on the bottom side of the bucket cylinder.

2. A hydraulic shovel according to claim 1, wherein the bucket rotation prevention means for preventing the bucket from free fall by maintaining the head side hold pressure when the bucket cylinder is retracted is provided at least on the head side of the bucket cylinder.

3. A hydraulic shovel according to claim 1, wherein a hoisting hook is rotatably supported between a pair of right and left bucket landcells protruding from the rear wall section of the bucket outwardly.

4. A hydraulic shovel according to claim 1, wherein a hoisting hook is hung from a stick boom top pin for attaching the bucket to a distal end section of the stick boom.

5. A hydraulic shovel according to claim 4, wherein:

a distal end face opposite to the back face of the stick boom comprises a hoisting hook receiving section having an opening and being capable of housing the hoisting hook;

a reinforcement member disposed around a peripheral section of the opening; and

an engagement member for engaging a hook section of the hoisting hook by hanging;

wherein the stick boom top pin is rotatably supported at a distal end of the stick boom; and

a base end of the hoisting hook is supported by the stick boom top pin.

6. A hydraulic shovel according to claim 5, wherein the hoisting hook is linked to a hook rotation driving mechanism for rotating about the stick boom top pin.