Mining or in situ disintegration of hard material – Hard material disintegrating machines – Rotary cutter head with advance direction coincident or...
Patent
1993-12-20
1995-08-01
Bagnell, David J.
Mining or in situ disintegration of hard material
Hard material disintegrating machines
Rotary cutter head with advance direction coincident or...
299 81, 299 90, E21D 908
Patent
active
054375002
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention concerns a tunneling machine for boring a tunnel, with a shield that can be driven into the soil and in which a cutting wheel, powered and equipped with ripping tools, is arranged.
2. Description of the Invention
Tunneling of this type are known and feature a cutting wheel with several cutting arms, where the ripped soil proceeds through the spaces in the cutting arms into the tunneling machine and is then removed. Owing to the high forces which occur, the hub area of the cutting wheel, originating from which the cutting arms extend radially outward, is of a massive and stabile design. Therefore, soil ripped in the area of the longitudinal axis of the cutting wheel needs to be moved in the radial direction of the cutting wheel up to one of the spaces between the cutting arms of the cutting wheel. Besides, since in the center area of the cutting wheel the velocity of the ripping tools contained there is lower than the velocity of the tools revolving on a larger radius, a dead core results often in the axis area of the cutting wheel, with essentially a soil displacement taking place there, instead of an active soil removal. The formation of a soil plug thus increases the forward resistance of the tunneling machine, especially in cohesive soil, such as loam and clay. To improve the escape of the soil in the dead core of the cutting wheel, slip layers have already been used. But these wear quickly, so that an initially slight forward resistance will in the course of time increase, due to the wear in the central area of the cutting wheel. The increased forward resistance with the prior tunneling machines reduces the rate of advance in tunneling and requires higher driving capacities.
The problem underlying the invention is to provide a tunneling machine which is characterized by a low forward resistance.
SUMMARY OF THE INVENTION
The present invention provides a tunneling machine including a center cutter disposed in the hub area of the cutting wheel which is rotatable relative to the cutting wheel and features as well ripping tools and a central cutting wheel.
The central cutting wheel of the center cutter makes it possible to work in the dead core area independently of the ripping with the larger cutting wheel. For that, the center cutter has for both directions of rotation a drive mechanism which is separate from the cutting wheel. To be able to remove the soil in the dead core quickly and simply, the center cutter has at least one inlet opening for the soil to be ripped. The inlet opening empties into a crusher space fashioned as a conical crusher with several crushing bars which are arranged, for one, on the hub of the central cutting wheel and, for another, on the inside of the tapered plate of the conical crusher.
Flushing and suction lines are provided for removal of the soil entering the crusher space.
The central cutting wheel of the center cutter features preferably a rim covering in the direction of advance an annular gap provided between the center cutter and the center cutter opening in the cutting wheel. In one embodiment of the invention, the central cutting wheel of the center cutter is provided with several inlet openings, on the rims of which there are shearing blades or other ripping tools provided. Specifically, it is possible to equip the central cutting wheel with several roller bits working in the direction of advance. Carbide tipping may be provided along the rim of the central cutting wheel of the center cutter.
BRIEF DESCRIPTION OF THE DRAWINGS
Two embodiments of the invention will be more fully described hereafter with the aid of the drawing, which shows in
FIG. 1, the front shield area of the tunneling machine according to the invention, as a section with a cut-away partial view of the center cutter;
FIG. 2, a view of the tunneling machine according to FIG. 1, viewed against the direction of advance;
FIG. 3, an embodiment of the inventional tunneling machine modified relative to FIG. 1, with a center cutter fe
REFERENCES:
patent: 2756037 (1956-07-01), Kirkpatrick
patent: 2864599 (1958-12-01), Masoni
patent: 3355215 (1967-11-01), Haspert et al.
patent: 4607889 (1986-08-01), Hagimoto et al.
Heerssen Rolf
Herrenknecht Martin
Lehmann Gebhard
Bagnell David J.
Herrenknecht GmbH
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