Mining or in situ disintegration of hard material – Hard material disintegrating machines – Rotary cutter head with advance direction coincident or...
Patent
1993-05-19
1994-11-01
Bagnell, David J.
Mining or in situ disintegration of hard material
Hard material disintegrating machines
Rotary cutter head with advance direction coincident or...
175404, 299 31, F21B 1004, E21D 910
Patent
active
053602609
DESCRIPTION:
BRIEF SUMMARY
The invention concerns a tunneling machine for application underground with a rotatively driven boring head base body, which is equipped with a fixed pilot borer and tool-bearing tool carriers that sweep radially by means of feed-piston gear units around axis of rotation between the point of application in the pilot hole and the gallery sides and that carry at least one roller boring tool.
DE-PS 31 40 707 presents a typical tunneling machine, in which the pilot borer, is coupled with a central driveshaft connected to the boring head base body. This driveshaft, on the one hand, limits the sweep angle of the tool-bearing tool carriers that sweep radially between the point of application in the pilot hole and the gallery sides, and on the other hand, has to transmit very large forces in connection with a pilot borer of large diameter.
The pilot borer has to have a diameter large enough so that in order to realize the advantage of undercutting, the roller tools of the sweepable tool bearer can, between the driveshaft and the borehole wall, effectively engage the rock face. A pilot boring head of that size necessitates the transmission of very high torque values and requires very high forces of application, resulting in highly inefficient energy consumption.
Moreover, the driveshaft must be able to withstand the shearing forces resulting from the large pilot boring head. In the implementation of a rigid shaft, one which carries the pilot borer, there arise further complications in construction in that it is difficult to find a place to locate the feed-piston gear units required for the sweepable tool-holding tool arms.
Deviating from such a style of tunneling machine, the unpublished patent application P40 15 462.9 presents another machine for cutting underground passages with a rotatively driven boring head, to which, for example, four sweepable tool arms holding roller boring tools are articulated. Since an arrangement of this type works without a pilot hole, and since at the same time, however, the roller boring tools are to work in accordance with the undercutting principle, a tool arm is provided which is pivotable, being nearly centrally articulated to the working head, in order to provide a suitable cavity for the engagement of the remaining tool carriers.
In the process very high forces occur for a single tool arm jointed eccentrically to the working head, which is to achieve the effect of a pilot borer. Such high forces cause considerable wear and tear. Furthermore, an essential disadvantage arises in such an arrangement in that a continuous operation, that is, a simultaneous hollowing out for undercutting and the undercutting proper cannot be accomplished.
Incumbent upon the invention is the task of developing a tunneling machine which on the basis of the simultaneity of the pilot boring and undercutting procedures avoids the aforementioned disadvantages, especially regarding the occurring torque values and shear forces. Such a tunneling machine should require only minimal forces of application vis-a-vis the surface to be worked by the pilot borer and thus conserve considerable energy and avoid the previous wear and tear through improvement in construction.
According to the invention, the problem is resolved in that the pilot borer is constructed as a ring borer that breaks out a drilling core through slits of an annular cavity, which consists of two parallel, boring-tool-carrying tool arms spaced apart from a central axis and articulated on a crossbeam of a support frame incorporating an advancing mechanism. In this arrangement the support frame surrounds the feed-piston gear units for the radially sweepable tool carriers. The support frame is positioned perpendicular to the tool carriers and extends parallel to the central axis at the boring base body.
The frame construction arranged at right angles to the sweepable tool carriers at the boring head base body allows the possibility of creating sufficient space for the feed-piston gear units of the sweepable tool carriers.
Beyond that, the possibility
REFERENCES:
patent: 2741462 (1956-04-01), Baca
Baumann Lothar E.
Kappelmann Hans G.
Mertens Volkmar
Schafeld Bernhard T.
Vorhoff Werner W.
Bagnell David J.
Bergwerksverband BmbH
Carpenter John W.
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