Hydraulic and earth engineering – Underground passageway – e.g. – tunnel – Boring
Patent
1992-03-17
1993-08-17
Taylor, Dennis L.
Hydraulic and earth engineering
Underground passageway, e.g., tunnel
Boring
405141, 405138, E21D 900
Patent
active
052362841
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a drilling apparatus for tunnel drive in soil or rock, the head of which is provided with a working tool, and to a method, wherein the drill head forward advance is controlled by means of a protecting tube.
Previously known is a drilling apparatus provided with one working tool a.o. from the U.S. Pat. No. 4,122,683. In the publication a working tool is described which cuts tunnel front wall through rotation. The excavated material runs into the drill head protecting tube and continues to the rear end of the apparatus. The apparatus has a plurality of grippers taking support from the tunnel walls, by means of which the direction of drilling can be adjusted through supporting the protecting tube against tunnel walls and turning either the tool or the movable drill head, for instance, by means of steering cylinders in a desired direction.
The U.S. Pat. No. 2,919,121 introduces a tunnel driving drilling apparatus by means of which excavated material is conducted to the inside of rotating tube. Outside this tube there is also the actual protecting tube enveloping the drill head portion. This tube is supported against the tunnel wall by means of wheels and expanding ring segments, and the direction of the apparatus is effected by these wheels and segments.
The disadvantage of the above solutions is the access of drill waste to the tunnel bottom during the drilling process, allowed by the placement of tool bit portions with relation to the protecting tube. A space is left open between drill bits and the protecting tube, and thus excavated waste simply piles up in this space. It is rather complicated to force the material inside the protecting tube or the conveying tube and not quite possible even on driving a tunnel in unbroken rock.
Due to the fact that a certain quantity of waste always remains in the tunnel in these cases, the alignment of drill head is disturbed since steering is effected through support from the tunnel wall. Especially in the lower tunnel parts, harmful drill waste is left, wedging itself between the protecting tube and the tunnel.
SUMMARY OF THE INVENTION
By means of the method and apparatus of this invention a crucial improvement of said disadvantages is achieved. In order to put this into practice, the method and apparatus according to the invention include two adjustable sliding elements supported against the tunnel bottom and position the center of gravity of the drill bit unit in the area between where these two elements are supported.
It can be considered the main advantage of this invention that the drill head rests steadily against the inner surface of the waste-free tunnel, whereby a simple direct forward drill head without any control equipment can be used. The solution according to this invention is preferably applied to tunnels with small-sized diameters, 800 mm at the best. The advantage of the invention is further increased by the fact that it is difficult to provide drill heads with small-sized diameters when control equipment is included.
BRIEF DESCRIPTION OF THE DRAWING
In the following, the invention is more closely described with reference to the enclosed drawings where
FIG. 1 is a drill head with tool.
FIGS. 2 and 3 are tunnels curved in the vertical plane.
FIG. 4 is a drilling apparatus steered by the force of gravity.
FIG. 5 is a drilling apparatus leaning against the tunnel bottom on bearing surfaces.
FIG. 6 is the cross-section of a hydraulic pressure distributor,
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a tool (4) provided with a bit (1), bit holder (51) and openings (2), along which drill waste is conducted by means of compressed air from bit front to protecting tube (3, 7). Compressed air enters the tool over a pipe (8) and at least a part of the air is conducted to the bit front to convey drill waste. Between bit holder (51) and the protecting tube enveloping it, there is a lap joint preventing access of drill waste to the outside of the protecting tube. Through placement and dir
REFERENCES:
patent: 2919121 (1959-12-01), Ruth
patent: 3733835 (1973-05-01), Jacobs
patent: 4122683 (1978-10-01), Follert et al.
patent: 4355924 (1982-10-01), Husemann et al.
patent: 4640646 (1987-02-01), Hentschel
patent: 5051033 (1991-09-01), Grotenhofer
McBee J. Russell
Taylor Dennis L.
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