Widening apparatus

An apparatus for widening microtunnels and/or for the destruction and replacement of ground-laid pipework and for the laying of new pipework possesses a tool which displaces the earth and/or destroys and/or displaces pipework laid in the earth, having a housing which is provided with an axial linkage seating, for example a housing passage for a linkage and with a linear drive which moves the tool, for example, on the linkage automatically from a launch pit to an arrival pit and simultaneously lays a follow-up pipe or a follow-up cable in the earth.

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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
 An old pipe 2 extends through the earth 1 between a launch pit 3 and an
 arrival pit 4, for example standard manholes. Located in the old pipe 2 is
 an inserted linkage 6, consisting of individual sections 5, details of
 which are described in German Published Application 196 08 980.
 Located in the arrival pit 4 is a frame 7 of L-shaped cross section which
 is anchored in the earth by means of an earth spike 8. Arranged on the
 baseplate of the frame 7 is an abutment plate 9, through which the front
 section 5 of the linkage 6 extends. Between a rung 10 and the abutment
 plate 9 is an L-shaped locking wedge 11, which prevents movement of the
 linkage 6 in the direction from the arrival pit 4 to the launch pit 3.
 In the launch pit 3 is a self-propelled bursting and clearing head 15
 having a housing 16 whose front end 12 is open and is designed partly as a
 cylinder 13, partly as a cone 17; it serves as a tool for destroying the
 old line 2 and for widening the earth 1. The clearing head 15 may be
 equipped with lubricant and/or flushing medium nozzles. In the interior of
 the housing 16 a plurality of dual-action hydraulic feed cylinders 18 are
 arranged in a circular manner around the linkage 6, their piston rods
 bearing on a collar 19 of the housing. The housing 16, open at the front,
 forms with the feed cylinders 18 a passage 20 for the linkage 6. The feed
 cylinders 18 are provided with spring-loaded pivotable locking pawls 21
 which, as depicted in FIG. 1, rest on a rung 10 of the linkage 6 on the
 one hand and on a stop 22 of the piston rod on the other. The upper
 locking pawl 21 can turn counterclockwise and the lower locking pawl 21
 clockwise.
 If the locking pawls can be adjusted so that their direction of action is
 reversed, the bursting and clearing head can also readily be moved counter
 to the direction of advance.
 Locking pawls 23 are likewise mounted in the collar 19, bearing on the one
 hand on a rung 10 of the linkage 6 and on the other on a housing stop 24.
 The upper locking pawl 23 can turn away over a rung 10 counterclockwise
 and the lower locking pawl 21 clockwise.
 Connected to the housing 16 is a follow-up pipe 25 through which pressure
 medium lines 26 are passed to the feed cylinders 18.
 The small diameter of the bursting and clearing head permits use at a short
 distance above the ground, so that no costly digging work is necessary in
 a standard manhole.
 In order to destroy the old pipe 2 with the tool 15, which may consist of
 two plug-on cones, and at the same time to displace the pipe shards
 laterally together with the earth surrounding the old pipe, the feed
 cylinders 18 are subjected to the action of hydraulic oil via the
 hydraulic oil lines 26, so that their piston rods, supported by the
 locking pawls 21 on a linkage rung 10, move out. Since the linkage 6 is
 unable to move in the direction of the launch pit 3 because of the
 abutment created by the locking wedge 11, when the piston rods extend, the
 clearing head 15 moves toward the arrival pit 4 by a distance
 corresponding to the stroke of the piston rods. When this occurs, the
 locking pawls 23 slide over the linkage rungs 10, located in front of them
 in the direction of advance, while the locking pawls 21 act as abutment
 stops and remain in the position shown in FIG. 1 until the piston rods are
 fully extended. In a second working step, the piston rods are retracted
 again, the locking pawls 21 now sliding over the linkage rungs 10 located
 in front of them in the direction of advance, while the locking pawls 23
 remain in the position shown in FIG. 1 and, together with the linkage rung
 10 adjacent to them, serve as an abutment for the inward movement of the
 piston rods.
 The two working steps described above are repeated in constant alternation
 until the bursting and clearing head 15 reaches the arrival pit 4 above
 the baseplate and the front end of the follow-up pipe 25 has arrived in
 the arrival pit 4. In this position, the clearing head can easily be
 removed in the free space between the abutment plate 9 and the wall of the
 pit or shaft.
 The length of the linkage sections 5 approximately corresponds to the
 length of the clearing head 15, so that the launch pit 3 and the arrival
 pit 4 need not be much larger in the direction of advance because the
 linkage sections 5 are fed vertically and can be connected to each other
 via a simple plug-type connection by latching, as is described in detail
 by German Published Application 196 08 980, which is deemed an integral
 part of the present description.
 In the example of embodiment according to FIG. 2 a traveling linkage 6 is
 used which is fixed counter to the direction of advance but able to be
 displaced stepwise In the direction of advance. To this end, two mutually,
 opposite locking pawls 27 are arranged on the abutment plate 9, serve in
 the position shown as a stop for the linkage rung 10 located in front of
 them in the direction of advance, and slide away over the linkage rungs 10
 lying in front of them in the event of a linkage movement in the direction
 of advance.
 In the clearing head 15 according to FIG. 2 the feed cylinders 18 are not
 provided with locking pawls 27 but are connected via clamping jaws 28, or
 alternatively permanently, to the linkage 6. Consequently, when the piston
 rods are extended, the clearing head 15 moves forward on the linkage 6,
 which is supported on the locking pawls 27 and therefore fixed, toward the
 arrival pit 4 until the piston rods are fully extended. At the end of this
 first working step the clearing head 15 is at least partially within the
 earth, in which it is fixed by wall friction in a manner such that it acts
 as an abutment when the piston rods entrain the linkage 6 in the direction
 of advance on retraction, that is to say on each return stroke. This is
 possible because the linkage rungs 10 in the arrival pit can move through
 in the direction of advance between the locking pawls 27 until the piston
 rods are fully retracted and the first working step is repeated.
 The interplay described previously between the advance of the clearing head
 with a fixed linkage 6 and extending piston rods on the one hand and the
 advance of the linkage with a fixed clearing head 15 during the retraction
 of the piston rods on the other hand is repeated until the clearing head
 15 has arrived in the arrival pit 4.
 The self-propelled clearing head according to the invention is suitable not
 only for the destruction of an old line but also for the widening of a
 pilot tunnel.
 Such a pilot tunnel can be produced with the aid of a drilling apparatus
 which consists of a tracklaying gear 28 with a platform 29, a traveling
 push-pull drive 30 and a clamping jaw locking system 31. With the help of
 a hollow drilling linkage 32 consisting of individual linkage sections a
 pilot tunnel 33 is made, in a first working step, in the form of an
 obliquely horizontal drilling from the surface of the ground to an arrival
 pit (not shown). In the arrival pit, the drilling head is removed from the
 drilling linkage 32 and replaced by a clearing head 34 (backreamer). The
 housing 35 of the clearing head 34 is connected to a follow-up pipe 25 and
 contains a hydraulic cylinder 36 which is guided on the end flange 37 of a
 hollow piston rod 38 integral with the housing 35. The bottom of the
 hydraulic cylinder 36 is connected to the hollow linkage 32 in a manner
 proof against twisting, this hollow linkage 32 having near to the bottom a
 transverse aperture 39 to a cylinder space 40 located in front of the
 flange 37 and being guided by the hollow piston rod 38, which thus
 functions as a linkage seating.
 If hydraulic oil from a pressure medium source (not shown) flows through
 the drilling linkage and thence through the transverse bore 39 into the
 cylinder space 40, the clearing head 34, 35 moves out of its position
 according to FIG. 7 into the earth (FIG. 8), when the drilling linkage is
 axially fixed by the locking system 31. As soon as the clearing head 34
 has reached the position according to FIG. 8, the locking system 31
 releases the linkage, which is then moved out of the pilot tunnel with the
 aid of the platform drilling apparatus 28, 29, 30 until the hollow piston
 has again reached its position according to FIG. 7. Thereafter the
 clamping jaws of the locking system 31 are again actuated and the
 hydraulic cylinder 36 is again subjected to the action of hydraulic oil
 until it is fully extended. This interplay of clearing head advance with
 fixed drilling linkage 32 on the one hand and drilling linkage reverse
 movement in the direction of advance or in the direction of the drilling
 apparatus 28, 29, 30 with the clearing head retained by the earth 1 on the
 other hand is repeated until the clearing head 34 has arrived at the
 surface of the ground.
 In the examples of embodiment according to FIGS. 6 to 8, however, the
 possibility also exists of retracting the linkage 32 immediately after the
 extension of the hollow cylinder 36 if the tensile force of the drilling
 apparatus 28, 29, 30 is not sufficient.
 The clearing head shown in FIG. 9 is constructed, in principle, in the same
 way as the clearing head 15 according to FIG. 1, but in this case the
 follow-up pipe 25 is connected not to the equipment housing 16 but to a
 sliding sleeve 41 arranged in the housing 16. The sliding sleeve 41
 possesses a flange 42 on which the end surface of the follow-up pipe 25
 bears. The flange 42 is guided in the housing 16 so that, when the piston
 rods are extended, the clearing head 15 moves over the fixed linkage 6
 toward the left into the earth 1, while the feed cylinders 18 with the
 sliding sleeve 41 and the follow-up pipe do not change their position.
 After the piston rods have been extended, they return into their initial
 position, the clearing head 15 not moving but the feed cylinders 18 with
 the sliding sleeve 41 and the follow-up pipe 25 being drawn into the
 clearing head housing 16. In this manner, the clearing head 15 and the
 follow-up pipe 25 are each moved alternately in the direction of advance.
 The clearing heads according to the invention need not be operated by means
 of hydraulic oil. Also suitable for this is a drilling or flushing medium
 suspension which emerges an the clearing head via nozzles.