Boom assembly

Abstract

There is provided a boom assembly bent at the center in a longitudinal direction so as to form a round shape protruding upward when seen from the side, comprising; a front boom sub assembly (47), the front boom sub assembly constituting the front of the center in the longitudinal direction of said boom assembly; and a rear boom sub assembly (48), the rear boom sub assembly constituting the rear of the center in the longitudinal direction of the boom assembly, wherein the front boom sub assembly (47) and the rear boom sub assembly (48) are symmetric when seen from the side, and portions from the midway positions in the longitudinal direction of the front boom sub assembly (47) and the rear boom sub assembly (48) to the center in the longitudinal direction of the boom assembly (12) have upper surfaces of arc shape protruding upward when seen from the side, and portions from the middles in the longitudinal direction of the front boom sub assembly (47) and the rear boom sub assembly (48) to ends in the longitudinal direction of the boom assembly (12) have upper surfaces of linear shape when seen from the side.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a front loader;

FIG. 2 is a side view of a tractor to which the front loader is mounted;

FIG. 3 is an exploded side view of a boom assembly;

FIG. 4 is a side view of boom assemblies having different lengths;

FIG. 5 is a side view of boom sub assemblies having different lengths;

FIG. 6 is a rear sectional view of a pivot connecting portion of a boom cylinder of the boom assembly;

FIG. 7 is a side view of the pivot connecting portion of the boom cylinder of the boom assembly; and

FIG. 8 is a side sectional view of the center in the longitudinal direction of the boom assembly.

Claims

1. A boom assembly bent at the center in a longitudinal direction so as to form a round shape protruding upward when seen from the side, comprising; a front boom sub assembly, said front boom sub assembly constituting the front of the center in the longitudinal direction of said boom assembly; anda rear boom sub assembly, said rear boom sub assembly constituting the rear of the center in the longitudinal direction of said boom assembly,wherein said front boom sub assembly and said rear boom sub assembly are symmetric to each other when seen from the side, and portions from the midway positions in the longitudinal direction of said front boom sub assembly and said rear boom sub assembly to the center in the longitudinal direction of the boom assembly have upper surfaces of arc shape protruding upward when seen from the side, and portions from the middles in the longitudinal direction of said front boom sub assembly and said rear boom sub assembly to ends in the longitudinal direction of the boom assembly have upper surfaces of linear shape when seen from the side.

2. The boom assembly according to claim 1, wherein bodies of said front boom sub assembly and said rear boom sub assembly are formed into a π-shape in section by right and left side walls and an upper wall connecting upper edges of the right and left side walls.

3. The boom assembly according to claim 1, wherein the boom assembly includes an operating tool swingably at a front end of said boom assembly, and is used in a loader in which a hydraulic cylinder that swings the operating tool is placed in an upper front of said boom assembly.

4. The boom assembly according to claim 2, wherein the boom assembly includes an operating tool swingably at a front end of said boom assembly, and is used in a loader in which a hydraulic cylinder that swings the operating tool is placed in an upper front of said boom assembly.