Hydraulic and earth engineering – Subterranean or submarine pipe or cable laying – retrieving,... – Advancing subterranean length of pipe or cable
Reexamination Certificate
1999-04-19
2001-06-12
Will, Thomas B. (Department: 3673)
Hydraulic and earth engineering
Subterranean or submarine pipe or cable laying, retrieving,...
Advancing subterranean length of pipe or cable
C405S154100, C405S156000
Reexamination Certificate
active
06244783
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an apparatus and a method for widening microtunnels, for example a pilot tunnel, and/or for the destruction of ground-laid pipework, by means of which simultaneously new pipework or alternatively a cable can be drawn into the widened microtunnel.
DESCRIPTION OF THE PRIOR ART
The laying of lines without the use of trenches has become increasingly important in recent years. In the course of this development, a method has, inter alia, become established whereby, with the aid of a stationary drilling apparatus, a pilot tunnel of relatively small diameter is initially drilled, for example to an arrival pit or a manhole, the drilling head is removed from the drilling linkage in the arrival pit, and the drilling linkage is fitted with a clearance tool of larger diameter which widens and/or removes the earth in the course of a backward movement of the linkage to the drilling apparatus. Such a method is described in German Patent Specification 4,220,430.
Methods and apparatuses are also known, for example from German Patent Specification 3,533,995, wherein an old pipe laid in the earth is destroyed with the aid of a self-propelled pneumatic hammer drill. In such methods, the pipe shards and the earth surrounding the old pipe are simultaneously displaced laterally and a new pipe is drawn in with the aid of the hammer drill. The destruction and replacement of ground-laid pipework can also be carried out with the aid of a stationary drilling apparatus whose linkage is fitted with a bursting head which destroys the old pipe.
Furthermore, it is known from U.S. Pat. No. 5,580,188 to push a linkage through an old line to an arrival pit or to an existing manhole and there fit it with a clearing head which destroys the old line and, simultaneously, widens the earth surrounding the old line and draws a new pipe into the widened microtunnel.
Finally, German Patent Specification 3,826,513 has also disclosed a method of laying supply lines in the earth without the use of trenches, in which a hammer drill is moved forward on an old line lying in the earth and thereby widens the earth.
In the horizontal laying of lines, it is often necessary to work under constricted circumstances, for example from a cellar space or from an existing manhole. This, however, is not possible if the length of the drill is greater than the dimensions of the space available. This problem arises in particular with the renovation of old pipes or drains, because the diameter of a standard manhole is only 1 meter and the diameter of the manhole aperture is only about 80 cm. These dimensions do not generally enable the known drilling apparatuses to be installed at the level of the old line which is to be replaced without digging and excavation work.
Problems also arise, however, if a launch pit and an arrival pit initially have to be excavated, because the volume of the earth to be removed therefrom, and possibly also to be transported away, is determined by the dimensions of the drilling apparatus.
The object of the invention is therefore to provide an apparatus and a method which permit a space-saving widening of a pilot tunnel or the destruction and replacement of an old line and can be used, in particular, in a standard manhole.
SUMMARY OF THE INVENTION
This object is achieved, first, by an apparatus having a tool with a housing, an axial seating for a linkage in the tool housing and a linear drive located in the housing and engaging on the linkage. This linear drive moves the housing with the tool along the linkage, which extends through a pilot tunnel or through an old pipe laid in the earth. When this is done the tool widens the pilot tunnel, or destroys an old line and displaces the line shards, for example into the surrounding earth, and simultaneously or in a further step draws into the widened microtunnel a line connected to the housing, for example pipework, a protective pipe or a cable.
If the linkage is a stationary linkage, then the tool moves continuously or stepwise on that linkage toward an arrival shaft or a target, while the linkage initially remains in the new pipe connected to the housing and is only removed therefrom when the tool, preferably a clearing head, has reached the arrival pit.
The apparatus can, however, also be operated in a manner whereby the clearing head initially moves forward over a certain distance, then the linear drive in the housing pushes the linkage in the direction of advance by preferably the same distance and the clearing head in turn is then moved forward by, preferably, the same distance.
The linear drive may consist of a plurality of feed cylinders, preferably arranged in a circular manner around the linkage or the linkage seating, and moving the housing with the tool by stages, or the housing with the tool and the linkage alternately stepwise, toward the destination point. A ring cylinder or, in a special alternative embodiment, a standard cylinder may likewise be used, the external diameter of which is usually somewhat smaller than the external diameter of the tools. The feed cylinders may be supported in the linkage and then, when their piston rods are extended, move the housing with the tool over the fixed linkage. The introduction of the piston rods, however, takes place with the housing stationary, so that the housing with the tool and the follow-up pipe attached to the housing are moved forward stepwise. If the linkage is not fixed in the direction of advance, however, the possibility exists that the piston rods of the feed cylinders, for example when introduced subsequently to the forward movement of the clearing head, will entrain the linkage and thus move it in the direction of advance by a distance corresponding to the piston stroke. This is associated with the advantage that the linkage with the housing moves stepwise in the direction of advance and the follow-up pipe connected to the housing cannot be damaged or contaminated by the linkage, which is a particular advantage in the case of drinking water lines. A further advantage of a linkage-free new pipe consists in the fact that it can safely be advanced together with a drain camera or similar monitoring and measurement equipment.
Particularly suitable feed cylinders are hydraulic cylinders, with which, unlike pneumatic feed cylinders, there is no danger that the follow-up pipe will be contaminated by the oil mist contained in the waste air. Because of the absence of waste air, hydraulic cylinders are also very advantageous for working in narrow manholes and launch pits; they also generate considerably less noise than pneumatic cylinders.
Particularly suitable as coupling means between the linkage on the one hand and the housing with the tool and/or the piston rods of the feed cylinders on the other are latching fingers or locking pawls, which, in one direction, lie in contact, for example, with the rungs of a ladder-type linkage and so create an abutment for the housing while they slide away in the opposite direction over the rungs. Also suitable as coupling means, however, are clamping jaws, which possess the advantage that they are suitable for any type of linkage; they merely need to be approximately adapted to the contour of the linkage in question.
Locking pawls may also serve to fix the linkage in one direction when the piston rods of the feed cylinders bear thereon in order to move the housing with the tool forward. In the other direction, the linkage can then be moved forward with the use of such a locking pawl.
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Balve Gerhard
Puttmann Franz-Josef
Merchant & Gould P.C.
Pechhold Alexandra K.
Tracto-Technik-Paul Schmidt Spezialmaschinen
Will Thomas B.
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