| US 7,555,854 B2 | ||
| Earth auger head and excavation method | ||
| Masaki Hatakeyama, Niigata (Japan) | ||
| Assigned to MLT Soil Co., Ltd., Niigata (Japan) | ||
| Filed on Nov. 29, 2007, as Appl. No. 11/947,082. | ||
| Claims priority of application No. 2006-323585 (JP), filed on Nov. 30, 2006; and application No. 2007-267403 (JP), filed on Oct. 15, 2007. | ||
| Prior Publication US 2008/0127528 A1, Jun. 05, 2008 | ||
| Int. Cl. E02F 3/10 (2006.01); E21B 4/00 (2006.01) | ||
| U.S. Cl. 37—350 [37/189; 175/296; 175/323; 175/262] | 6 Claims |
| 1. An earth auger head comprising:
a rotary excavation mechanism part in which a spiral vane used to discharge earth is provided to an outer circumference of
a rotary tubular part, and in which an excavating bit whose outer circumferential side protrudes flirt her downward than the
central side is provided to a lower end of the spiral vane; and
a pneumatic percussive excavation mechanism part that is installed inside the rotary tubular part and is disposed so that
a percussive body is accommodated in a position that is higher than the lower tip end of the excavating bit,
wherein an excavating rod connecting part is provided to the upper part of the rotary tubular part of the rotary excavation
mechanism part, a high pressure air supply path is formed communicating between the connecting part and a high pressure air
supply part in the internally installed percussive excavation mechanism part, a switching valve that is operated by an external
operation is disposed at an intermediate point along the high pressure air supply path, and a liquid discharge path is formed
so as to open on the outer circumference of the rotary tubular part connected with the high pressure air supply path via the
switching valve.
|