CUTTING WHEEL FOR A DIAPHRAGM WALL CUTTER AND METHOD FOR CONVERTING A CUTTING WHEEL

Description

The invention relates to a cutting wheel for a diaphragm wall cutter, with a drum-shaped hub, on the outer circumference of which there are arranged receptacles for cutting teeth and at least one holder for a folding tooth, wherein the holder has a bearing pin as a pivot axis for pivotably and releasably holding the folding tooth, according to the preamble of claim 1.

The invention further relates to a method for converting a cutting wheel according to claim 12.

Generic cutting wheels for diaphragm wall cutters can be found, for example, in EP 1 548 192 B1 or EP 0 291 027 B1. The problem with diaphragm wall cutters with cutting wheels arranged laterally on an end shield is that soil areas directly below the end shield cannot be easily removed by the cutting wheels. In the case of softer soils, the end shield together with the weight of the diaphragm wall cutter may easily break a ridge of soil forming underneath the end shield. In the case of harder soils, the ridge underneath the end shield poses a problem and may lead to undesirable deflection of the diaphragm wall cutter.

To avoid this, on the cutting wheels so-called folding teeth can be mounted in a manner, so that they can be pivoted or folded, on holders on the side of the cutting wheels which is adjacent to the end shield. By using a cam control system with control strips on the end shield and control arms on the folding teeth, for example, these can be folded out into an area below the end shield, in order to work off an underlying soil area, while when the cutting wheel continues to rotate, the folding teeth are folded in again so that the end shield is not damaged by the cutting teeth.

If the folding teeth are not required in the case of softer soils, they are a hindrance to efficient milling operation, as a rotational speed of the cutting wheels is limited by the folding teeth. At higher rotational speeds, a correspondingly high number of impacts may occur due to the folding, as well as considerable friction and correspondingly high wear on the cam control system.

It is known to remove the folding teeth in this case. However, the lack of removal teeth on the outer circumference of the cutting wheel also impairs efficient milling operation and leads to high wear on the holders without removal teeth.

It is also known to hold available different cutting wheels for different soil types. These then have to be replaced. However, replacing the cutting wheels with weight up to several tonnes is time-consuming and labour-intensive.

The object underlying the invention is to specify a cutting wheel for a diaphragm wall cutter and a method for conversion, with which a particularly efficient milling operation is made possible.

The object is achieved, on the one hand, by a cutting wheel having the features of claim 1 and, on the other hand, by a method having the features of claim 12. Preferred embodiments are specified in the dependent claims.

The diaphragm wall cutter according to the invention is characterised in that a fixing device is arranged on the holder and is configured to hold a fixed tooth mounted on the bearing pin in a fixed position.

A first aspect of the invention is to provide a fixing device on the holder in the case of pivotable or foldable holders of the folding teeth, by means of which fixing device a removal tooth, which is arranged on the bearing pin of the holder, can be fixed or secured in a fixed position, preferably a position projecting radially outwards. For this purpose, it may, in particular be expedient to remove the folding tooth mounted pivotably on the bearing pin and to replace it with a special fixed tooth. Alternatively, it is also possible to convert the existing folding tooth, for example by removing the portion with the control arm, so that it is then held in a fixed position on the bearing pin by means of the fixing device and can no longer fold or pivot. In doing so, it must be ensured that a cam control system for positive control of the folding movement of the folding tooth is taken out of operation, for example by releasing the control arm on the folding tooth.

In principle, the fixing device can be configured in any known manner, wherein the fixed tooth can be fixed in position in a form-fitting and/or force-fitting manner. In particular, clamping devices, preferably with clamping clamps, can be arranged for force-fit fixing. Form-fit fixing can be achieved using corresponding engagement elements or locking elements.

A preferred embodiment of the invention resides in that the holder has two bearing blocks which are spaced apart from one another and between which the bearing pin extends and is releasably mounted thereon. The bearing pin preferably extends thereby in a transverse direction to an axis of rotation of the cutting wheel, so that a folding tooth can be folded about the bearing pin, in particular in the direction towards an end shield, on which the cutting wheel is rotatably mounted. The holder with the two bearing blocks is preferably located on the outer circumference of the drum-shaped hub on an edge area adjacent to the end shield of a diaphragm wall cutter. Preferably, several holders are arranged evenly around the circumference of each cutting wheel, in particular two, three or four holders.

According to a further embodiment of the invention, it is preferable that a first receiving hole for receiving a first end of the bearing pin is designed on a first bearing block and a second receiving hole for receiving the second end of the bearing pin is designed on a second bearing block. The bearing pin is preferably cylindrical in shape and forms a pivot axis. A stable mounting of the bearing pin is achieved by accommodating the bearing pin in the two opposing receiving holes in the two bearing blocks.

According to the invention, an advantageous further configuration resides in that at least one receiving hole is configured as a through-hole for inserting and/or sliding out the bearing pin. The two receiving holes have thereby a common centre axis, wherein at least one receiving hole is configured as a through-hole. This means that the bearing pin can be easily inserted through the preferably cylindrical through-hole and inserted into the other receiving hole. The other receiving hole can be a blind hole or also a through-hole. The bearing pin can be secured in the receiving holes by using a suitable securing device, such as one or more locking screws.

The fixing device can be configured in basically any suitable way which is configured to hold a removal tooth held on the bearing pin in a fixed position so that the removal tooth is not pivotable on the cylindrical bearing pin. Here, it is particularly preferable that the fixing device has at least one locking hole for receiving a locking pin in the holder. In particular, a locking hole can be provided on one or both bearing blocks of a holder, into which a locking pin is inserted for form-fit and/or force-fit fixing of the fixed tooth on the bearing pin. In particular, the locking pin forms a positive connection between the holder and the removal tooth mounted on the bearing pin. This ensures that the tooth is fixed in the exact position on the bearing pin.

A further advantageous configuration of the invention resides in that two locking holes are provided and that a first locking hole is formed on the first bearing block and a second locking hole is formed on the second bearing block. In particular, a through-hole can be designed on the fixed tooth to be received, wherein a single locking pin is used to fix the removal tooth in that the removal bolt extends from the first locking hole through the through-hole on the removal tooth into the second locking hole on the opposite bearing block. This allows the fixed tooth to be reliably fixed to the holder despite the configuration of a cylindrical bearing pin.

A preferred embodiment of the invention resides in that a folding tooth is pivotably mounted on the bearing pin to form a milling tooth with a folding tooth on the at least one holder. In the sense of the invention, a folding tooth is a removal tooth pivotably mounted on the bearing pin. This creates a cutting wheel which can be used in the conventional manner, wherein the folding tooth can be pivoted during milling operation from a radially directed retracted position to run past the end shield into an inclined folded or removal position, in which the folding tooth can remove a ground material below the end shield. During the rotation of a cutting wheel, the folding tooth can be pivoted or adjusted between the two positions in a fundamentally known manner in cooperation with a control bar, which is fixed relative to the end shield, via a control arm or control portion on the folding tooth. The removal tooth can be configured with at least one cutting edge, for example as a cutting tooth, and/or with at least one removal tip, for example as a round shank chisel.

According to one embodiment of the invention, it is provided that here a dummy plug is inserted into the at least one locking hole to form a cutting wheel with a folding tooth. If the locking hole of the fixing device is not required in the conventional use of the cutting wheel with folding tooth, an inserted dummy plug ensures that the locking hole on the holder is not unnecessarily worn or clogged by soil material.

According to a further embodiment of the invention, it is preferable that a fixed tooth is mounted on the bearing pin to form a cutting wheel with a fixed tooth, which fixed tooth is fixedly held by means of the fixing device. In the sense of the invention, the fixed tooth constitutes a removal tooth which is held in a fixed position on the bearing pin by means of the fixing device. The fixed tooth can here, in particular, have a radial alignment which corresponds to an alignment of the other removal teeth on the cutting wheel or is largely similar to this and, in particular, ensures a running past the end shield. The fixed tooth does not remove soil from below the end shield.

Preferably, the fixed tooth does not correspond to the folding tooth. To convert the cutting wheel in this case, it is first necessary to remove the folding tooth with its control arm and replace it with a fixed tooth. The fixed tooth is thereby also mounted on the preferably cylindrical bearing pin, wherein the fixed tooth is configured, however, to be fixed to the holder in the desired position by means of the fixing device. In particular, the fixed tooth can be designed shorter than a folding tooth.

It is particularly advantageous that, in order to form a cutting wheel with the fixed tooth, a locking pin is inserted into the at least one locking hole to hold the fixed tooth stationary and that the at least one locking pin extends into a suitable recess in or on the fixed tooth and the fixed tooth is fixed on the bearing pin.

In principle, a single locking pin can be provided on each bearing block and engages in a correspondingly suitable recess on the fixed tooth and thus secures it form-fittingly. Preferably, a single locking pin can be provided, which extends from a first bearing block to a second bearing block of the holder, in particular through a receptacle on the fixed tooth in the design of a through-hole. This achieves a particularly stable fixing of the fixed tooth on the holder. The fixed tooth sits on the bearing pin on the one hand and on the locking pin on the other hand.

The invention further comprises a diaphragm wall cutter with a cutter frame, on the underside of which at least one end shield is arranged for rotatably supporting at least one cutting wheel, wherein at least one cutting wheel according to the invention is arranged.

Preferably, the diaphragm wall cutter has several cutting wheels, in particular one cutting wheel respectively on each side of a plate-shaped end shield. In this way, a pair of cutting wheels with a preferably coaxial axis of rotation is formed on one end shield. It is particularly preferable that two end shields, each with a pair of cutting wheels, are arranged on the underside of the cutter frame.

The invention can be used with any type of diaphragm wall cutter, in particular with a CSM cutter in which the cutting wheels have a removal and mixing function for producing a soil mortar and no guide frame needs to be arranged, or a cutter with a rack-type guide frame, for example for a single or two-phase process.

The invention further comprises a method for converting a cutting wheel according to the invention, wherein the method is characterised in that a folding tooth is pivotably mounted on the bearing pin of the at least one holder of the cutting wheel and is released and removed, and in that a fixed tooth is arranged on the bearing pin and is held in a fixed position by the fixing device on the holder. In this way, a cutting wheel and in particular a cutting wheel on a diaphragm wall cutter can be efficiently converted. By replacing one or more folding teeth with fixed teeth, it is enabled to operate the cutting wheels at a higher speed in softer soils. This protects the cam control system of the folding teeth during such a use and prevents unnecessary wear.

A preferred embodiment variant of the invention resides in that the fixed tooth on the holder of the cutting wheel is released from the bearing pin and removed and that a folding tooth is arranged on the bearing pin, which is pivotably mounted on the bearing pin of the at least one holder of the cutting wheel. It is therefore also possible to convert in the opposite way without any problems, so that in the case of a cutting wheel with fixed teeth, folding teeth can easily be used with the existing holder with bearing pin if this is required when cutting harder soil layers.

The invention is explained in more detail below with reference to preferred exemplary embodiments, which are shown schematically in the drawings. The drawings show:

FIG. 1 a perspective view of a construction machine with a diaphragm wall cutter according to the invention;

FIG. 2 an enlarged view of a diaphragm wall cutter according to the invention;

FIG. 3 a perspective view of a cutting wheel with folding tooth according to the invention;

FIG. 4 a cross-sectional view of a detail of a cutting wheel according to the invention with folding tooth;

FIG. 5 a partially sectional perspective view of a holder with folding tooth on a cutting wheel according to the invention;

FIG. 6 a perspective view of a cutting wheel according to the invention with fixed tooth; and

FIG. 7 a partially sectional perspective view of the holder on the cutting wheel according to FIG. 6 with fixed tooth.

A construction machine 1 with a diaphragm wall cutter 10 according to the invention is shown in FIG. 1, which is configured as a so-called CSM cutter. The construction machine 1 can have a carrier device 2, which can be configured to can move with an undercarriage 3. Preferably, the undercarriage 3 can comprise a crawler chassis. A superstructure 4 is arranged on the undercarriage 3 and is preferably mounted so that it can rotate about a vertical axis of rotation. A mast 5, which is preferably vertical in operation, can be articulated to the carrier device 2, in particular the superstructure 4, via an adjustment mechanism 7. The adjustment mechanism 7 can preferably be used to change the distance between the mast 5 and the superstructure 4 and to angle the mast relative to the vertical.

The diaphragm wall cutter 10 according to the invention can be moved vertically along the mast 5 with a lifting device 6 for inserting into the ground. In the illustrated exemplary embodiment, the lifting device 6 has a guide rod with which the diaphragm wall cutter 10 can be guided along the mast 5. Furthermore, a propulsion force can also be exerted downwards on the diaphragm wall cutter 10 via the rod using a propulsion device, not shown in detail, in order to increase the pressure force during milling. A rod-shaped lifting device 6 can be used advantageously if the diaphragm wall cutter 10 has a small, compact cutter frame 12, which has no guide surfaces for guiding along the cutter walls.

In principle, the lifting device 6 can also have a support cable instead of a guide rod, wherein the diaphragm wall cutter 10 then preferably has a box-shaped cutter frame 12 with guide surfaces to guide the diaphragm wall cutter 10 along the walls of the cut trench formed.

In the diaphragm wall cutter 10 according to FIG. 2, a connection device for the lifting device can be arranged on an upper side of the cutter frame 12 and preferably two plate-shaped end shields 14 on a lower side, on each of which a cutting wheel 20 according to the invention is mounted on both sides. The cutting wheels 20 on a common end shield 14 form a so-called pair of cutting wheels 20, which are rotatable about a common axis of rotation. Rotation can be effected by a suitable rotary drive, such as a hub motor in the hubs of the cutting wheels 20 or via one or more drive motors on the cutter frame 12, wherein torque transmission can then be effected via a corresponding gear arrangement.

A single cutting wheel 20 is shown in more detail in FIG. 3. This preferably has a drum-shaped hub 22, on the outer circumference of which radially projecting, plate-shaped receptacles 24 are attached in a distributed manner, on each of which a milling tooth 26 is releasably and replaceably mounted in a fundamentally known manner.

A holder 30 for a folding tooth 50 is arranged on an inner side of the hub 22 facing the end shield 14. The holder 30 can have a first bearing block 31 and a second bearing block 32 spaced apart in the circumferential direction, between which the folding tooth 50 is pivotably mounted. The folding tooth 50 can here preferably have an approximately central bearing portion 51, on which is adjoined radially outwards a receiving portion 52 for releasably receiving and holding a milling tooth 26. Furthermore, a control arm 54 extending radially inwards away from the bearing portion 51 can be arranged with a sliding element 56 for controlling the pivoting movement of the folding tooth 50. One or more removing strips 35 can be attached to the outer sides of the two bearing blocks 31, 32 facing away from the folding tooth 50 in order to reduce wear and improve the removal rate.

A fundamentally known mechanical control system for controlling the movement of the folding tooth 50 during the rotation of the cutting wheel 20 is shown in the schematic diagram in FIG. 4. In the cross-sectional representation of FIG. 4, a lower region of an end shield 14 is shown, to the two side faces of which a cutting wheel 20, which is only partially shown, is respectively arranged with a hub 22. An annular control strip 16, in each case with an outwardly directed control surface for forming a cam control system, is arranged on each of the outer sides of the end shield 14.

In FIG. 4, a plate-shaped holder 24 for a milling tooth 26 is shown on the right-hand cutting wheel 20 on the hub 22 on an axially outer side, and respectively a holder 30 with a first bearing block 31 is shown on an axially inner side. A preferably substantially cylindrical bearing pin 38, which forms a pivot axis 39 for the folding tooth 50, can extend between the bearing blocks 31, 32 on the holder 30.

The folding tooth 50 is pivotably mounted on the bearing pin 38 of the holder 30 with its bearing portion 51 and a through-hole 53 provided therein. The receiving portion 52 of the folding tooth 50 extends downwards to receive a milling tooth 26. The control arm 54 with a sliding element 56, which serves as a kind of control cam, is arranged radially in the direction of the hub 22 on the bearing portion 51 of the folding tooth 50. The folding tooth 50 is mounted here in such a way that the sliding element 56 is pressed against the annular control strip 16 on the end shield 14.

According to the outer control surface on the control bar 16, the folding tooth 50 can thus be pivoted between a retracted position, in which the receiving portion 52 with the milling tooth 26 is directed substantially radially to the hub 22 and to the axis of rotation of the cutting wheel 20, and a folding or removal position shown in FIG. 4. In the removal position shown in FIG. 4, the milling tooth 26 on the folding tooth 50 is pivoted into an area below the end shield 14, in order to remove soil material in this position and thus contribute to protecting the end shield 14 as well as to increasing the removal rate and to precisely guiding the cutting wheel 20 in the soil. The folding tooth 50 can be in the folding position for preferably more than 180° during one rotation, in order to remove in this way the soil in the area of the end shield 14 over the entire length of the trench.

The cutting wheel 20 according to the invention with the holder 30 is explained in further detail below in conjunction with the partial sectional view according to FIG. 5. The holder 30 according to the invention has a first bearing block 31 with a first receiving hole 33 and a second bearing block 32 with a second receiving hole 34, which is orientated coaxially to the first receiving hole 33. To receive a folding tooth 50, the bearing block 38 can be pushed into the receiving holes 33, 34, which are preferably each open on both sides, and at the same time through the through-hole 53 on the folding tooth 50, as shown clearly in FIG. 5. The folding tooth is pivotably mounted on the fixed bearing pin 38 about the pivot axis 39 via bushes 58.

Furthermore, the holder 30 according to the invention is configured with a first locking hole 41 on the first bearing block 31 and a second locking hole 41 on the second bearing block 32, each of which locking holes is also configured as a through-hole. In the illustration according to FIG. 5, dummy plugs 46 are inserted into the two locking holes 41, 42, as the locking holes 41, 42 are not required when a folding tooth 50 is pivotably held.

According to the invention, a folding tooth 50 mounted in this way can be replaced by a fixed tooth 60 or, if necessary, converted for this purpose. FIGS. 6 and 7 show an option according to the invention, wherein the folding tooth 50 as shown in FIG. 5 is being first removed from the holder 30 by releasing the bearing pin 38. A fixed tooth 60 is then inserted into the holder 30 between the first bearing block 31 and the second bearing block 32, wherein the bearing pin 38 is again inserted into the two receiving holes 33, 34 and into a through-hole 63 on the fixed tooth 60 and is secured.

Similarly to a folding tooth 50, the fixed tooth 60 has a bearing portion 61 and a radially outwardly adjoining receiving portion 62 for releasably receiving a milling tooth 26. However, in the illustrated exemplary embodiment, the fixed tooth 60 does not have a control arm for interaction with a control strip on the end shield.

However, a fixing portion 64 with recesses 66 for forming a through-hole adjoins the bearing portion 61 of the fixed tooth 60 radially inwards. To form a fixing device 40, a locking pin 48 is inserted into the two locking holes 41, 42 in the bearing blocks 31, 32. Any dummy plugs 46 that may be present can be removed, if necessary, from the locking holes 41, 42 beforehand. The locking holes 41, 42 in the bearing blocks 31, 32 are here aligned with the fixed tooth 60 on the bearing pin 38 in such a way that they are coaxially aligned with the at least one recess 66, so that the locking pin 48 extends from the first locking hole 41 in the first bearing block 31 through the recesses 66 on the fixed tooth 60 up to the second locking hole 42 on the bearing block 32.

The fixed tooth 60 thus sits both on the bearing pin 38 and on the locking pin 48, wherein the two bolts 38, 48 are each held by the two bearing blocks 31, 32. This results in a fixed, non-pivotable mounting of the fixed tooth 60 in the holder 30. The cutting tooth 26 mounted on the fixed tooth 60 is preferably radially directed so that running past the end shield 14 is easily possible.