Cutting head for machining pile heads

Abstract

A cutting head (1) having an axis of rotation (x) and serving to machine a pile head (80) of a pile (8) comprising a pile core (81), a pile jacket (82) and a metal exterior (83) interposed therebetween, comprises a coupling device (13) connectable to a drive shaft (2) of a drive device, a central milling cutter (11) comprising a number of central chisels (111) attached to the underside of an inner ring plate (112) and a ring milling cutter (12) comprising a number of ring chisels (121) attached to the underside of an outer ring plate (122), the central milling cutter (11) and the ring milling cutter (12) being connected to each other in coaxial alignment with the axis of rotation (x), the outer ring plate (122) surrounding the inner ring plate (112) separated by its intermediate circular ring area (kr2). According to the present invention, the inner ring plate (112) has at least one transfer opening (1120A, 1120B) leading from the lower side to the upper side of the inner ring plate (112), the transfer openings (1120A, 1120B) being adjacent on the lower side by conveyor shovels (119A, 119B) which at least partially protrude into the working area of ​​the central chisel (111), and the transfer openings (1120A, 1120B) being adjacent on the upper side by conveyor spirals (113A, 113B).

Description

[Technical field]

[0001] The present invention relates to a cutting head for machining pile heads. [Background technology]

[0002] WO2008135365 discloses a cutting head for machining the pile head of a pile comprising a pile core and a pile jacket, and a metal armour provided between the pile core and the pile jacket.

[0003] This kind of machined concrete pile is typically provided on unstable ground to support a structure and consists of concrete capable of undergoing pressure and reinforcing steel capable of undergoing tension. The dimensions of the pile are selected depending on the structure and the ground and can vary over a wide range. Typically piles with lengths of 5m to 50m and diameters of 0.4m to 2.5m are used. To construct the pile, a hole is drilled in the ground into which the pipe is inserted. Armouring iron is inserted into the pipe and concrete is poured. The earth material at the bottom of the pipe is usually displaced upwards and is found at the top of the pile when the displacement is complete, since it does not have the required strength. Furthermore, the pile or pile head usually does not have the required dimensions. The pile head may also lack the necessary connecting elements for the structure. Therefore, the pile head is usually machined and rebuilt with the required dimensions and quality.

[0004] For this purpose, a prefabricated, usually cylindrical pile head is machined by a cutting head over a length typically ranging from 0.5 m to 1.5 m in order to remove the missing concrete. The concrete must be removed in such a way that the armouring, typically in the form of a sleeve, which is typically placed coaxially to the axis of rotation of the pile, as well as the intact concrete below the pile head, are not damaged. After removing the missing or excess concrete to expose the armouring, the armouring is usually extended with auxiliary armouring and a formwork is provided corresponding to the dimensions of the new pile head to be constructed. The formwork is then filled with concrete and removed after the concrete has hardened.

[0005] Traditionally, when working with the pile head, the pile core was cut down to the border of the armoring iron. Subsequently, the pile jacket was cut down to the armoring iron. This process not only usually takes a long time, but also often results in damage to the armoring. Moreover, especially when working with the pile jacket, splitting of previously intact concrete occurs, which significantly reduces the available cross-section of the concrete pile and accordingly increases the surface pressure transmitted from the concrete pile to the construction. Thus, the corresponding damage to the concrete pile often resulted in considerable consequential damage to the object constructed on the defective pile head. To avoid such consequential damage, the defective pile and pile head had to be repaired at great expense and effort.

[0006] Therefore, when working at pile heads, not only does the time factor play an important role, but also the high-quality completion of the pile head, especially which forms an important part of the foundation of a structure such as a building or bridge.

[0007] The cutting head disclosed in WO2008135365, which is mounted on a construction vehicle such as a hydraulic excavator, has made considerable progress in terms of the machining time as well as the machining quality of the pile head. The cutting head comprises a coupling device connectable to a drive shaft, a central milling cutter provided with a number of central chisels and a ring milling cutter provided with a number of ring chisels, the central milling cutter and the ring milling cutter being fixedly connected to each other and aligned coaxially with the rotation axis of the drive shaft. The cutting head makes it possible to simultaneously remove the pile core and the pile jacket without damaging the pile outer covering located between the central milling cutter and the ring milling cutter.

[0008] In spite of the significant improvements in machining of pile heads achieved with this cutting head, there was still a need to develop a cutting head that would allow the pile head to be machined even faster and more carefully. However, increasing the working speed of the equipment usually results in a qualitatively inferior work result, which is unacceptable with respect to the fundamental importance of the machined object or pile head.

[0009] The present invention is therefore based on the object of making an improved cutting head for machining pile heads.

[0010] By means of the cutting head, the pile head of the concrete pile shall be machined with reduced force at the same time with a higher working speed and higher working quality. The cutting head shall be able to penetrate more advantageously into the pile head, the pile core and the pile jacket so that the concrete material can be removed with reduced force and at the same time, by reducing the force, the risk of damage to the machined pile head can be reduced.

[0011] When machining the pile head, the concrete shall be treated gently so that the accelerated material removal does not cause cracks and fissures in the pile head, and at the same time the load on the cutting tool or chisel shall be reduced, which shall correspondingly reduce the maintenance effort on the cutting head.

[0012] The cutting head shall in particular ensure that no tears occur in the pile jacket during machining of the pile head, resulting in a correspondingly high repair effort depending on the size.

[0013] The central drilling units and cutting tools are also advantageously mountable and dismountable in any desired number, so that in this respect too the maintenance efforts are low and the cutting heads can be configured and adapted with little effort to the piles to be machined, which can have diameters of more than 2 m.

[0014] This problem is solved by a cutting head having the features of claim 1. Advantageous embodiments of the invention are specified in the further claims. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] International Publication No. 2008135365 Brochure Summary of the Invention

[0016] The cutting head is used to machine the pile head of a pile, typically a concrete pile comprising a pile core, a pile jacket and a metal armour located between the pile core and the pile jacket.

[0017] The cutting head, which in use is rotated about its longitudinal axis or axis of rotation, comprises a coupling device connectable to a drive shaft of a drive device, a central milling cutter with a plurality of central chisels attached to the underside of an inner ring plate, and a ring milling cutter with a plurality of ring chisels attached to the underside of an outer ring plate, the central milling cutter and the ring milling cutter being connected to each other in coaxial alignment with the axis of rotation, and the outer ring plate surrounding the inner ring plate separated by an intermediate circular ring area thereof.

[0018] According to the invention, the inner ring plate is provided with at least one transfer opening leading from the underside to the upper side of the inner ring plate, the transfer opening being bounded on the underside by a conveyor shovel which at least partially projects into the working area of ​​the central chisel, and the transfer opening being bounded on the upper side by a conveyor spiral.

[0019] The cutting head according to the invention makes it possible to simultaneously remove segments of the pile core and pile jacket without damaging the pile jacket located in the central circular ring area. The machining is performed with such high precision that the concrete can be removed even at small distances of a few centimeters from the jacket. The remaining thin concrete sleeve with the jacket surrounded can then be quickly removed using another tool, for example pliers.

[0020] It is particularly advantageous that the segments of the pile core and pile jacket can be removed by a linear descent of the cutting head. Complex movements of the tool, which are difficult to perform and can lead to damage to the pile head, are no longer necessary. The pile head can therefore be machined in a short time without causing damage.

[0021] Due to the linear displacement of the cutting head and the correspondingly calculable force effect on the tool, the load and wear on the cutting head are also reduced and therefore only maintenance is required at longer intervals.

[0022] At least one conveyor shovel extending into the working area of ​​the chisels allows the cut material removed from the concrete core to be collected and fed through the associated transfer opening into the associated conveyor spiral. By removing the cut material, large obstacles are removed from the working area of ​​the chisels, allowing the cutting heads to rotate with reduced resistance and the central chisel to penetrate into the pile core with reduced resistance. On the one hand, the efficiency of the cutting tools is increased and, on the other hand, their load is reduced.

[0023] Thus, the cutting head of the present invention provides a systematic material flow, easing the cutting process and allowing efficient removal of the pile core and pile jacket. Due to the systematic material flow through the at least one transfer opening, the inner ring plate can be provided with a large surface area for assembling the central chisels. Thus, the large mounting surface of the inner ring plate does not impair the material flow. Thus, the desired number of central chisels can be mounted on the underside of the inner ring plate.

[0024] The cut material can be removed particularly efficiently if the inner ring plate is provided with two transfer openings, each of which is adjacent on the lower side to a conveyor shovel that at least partially projects into the working area of ​​the central chisel and adjacent on the upper side to a conveyor spiral. In order to allow the cut material to flow into the conveyor spiral with minimal resistance, each transfer opening is preferably adjacent by a connecting surface on the upper side of the inner ring plate, which ensures a layered or unobstructed transition from the conveyor shovel to the associated conveyor spiral.

[0025] Preferably, the transfer opening and the conveyor shovel and the central chisel are arranged in pairs, diametrically opposite each other and equidistant from the axis of rotation. The conveyor shovel, the central chisel and the ring chisel are also preferably provided in pairs at the same height. This ensures that the tools or chisels diametrically opposite each other always act identically on the pile head, avoiding disturbing moments or forces caused by asymmetries that may stress the cutting head and disturb its guidance. The cutting head can thus be optimally guided and operated with minimal forces. Forces acting transversely on the cutting head, which may be unfavorable for the installed tools, such as the chisel and preferably the installed central drill unit, are avoided.

[0026] Preferably, the inner ring plate is connected to the underside of the shaft and the outer ring plate is connected to the underside of a mounting cylinder, whereby the shaft and the mounting cylinder are coaxially aligned with the axis of rotation and connected to a connecting plate on the upper side of which the coupling device is arranged. The mounting cylinder preferably comprises at least one outlet window through which the conveyed cutting material can be discharged and at least one mounting window, for example allowing manual access to the coupling device.

[0027] In a further preferred embodiment, at least one conveyor spiral or two conveyor spirals, preferably rotated 180° relative to each other, are provided with side walls in the lower section, which is preferably selected depending on the height of the pile head to be machined. The side walls ensure that the cut material in the lower section cannot escape the conveyor spiral and can be transported from the remaining area of ​​the pile head with the armoring. Only after being transported from this area can the cut material laterally leave the upper section of the conveyor spiral, which is not provided with side walls, and leave the cutting head through at least one exit window. The side walls of the conveyor spiral thus ensure the transport of material from the inner ring plate to the area of ​​the conveyor spiral where the cut material is laterally released. The side walls can be integrally formed or welded on the conveyor spiral, which is made, for example, of sheet metal.

[0028] Below the inner ring plate there is a central drill unit, preferably aligned coaxially with the axis of rotation, which extends beyond the central chisel and the ring chisel in the cutting direction and thus penetrates the pile head or pile core first, thereby performing a guiding or piloting function and ensuring that the central chisel and the ring chisel can follow a circular working path.

[0029] In a further preferred embodiment, at least one radial shovel is provided on the underside of the inner ring plate, connected to the central drill unit and preferably aligned at least approximately radially with respect to the axis of rotation. Preferably, at least one radial shovel extends from the central drill unit to at least one transfer opening. Thus, preferably, a radial shovel is associated with each transfer opening. The at least one radial shovel, for example a straight or curved plate, ensures that the cutting material released from the central drill unit and the radially inner central chisel is guided outwards towards the associated transfer opening. The course of the lower or leading edge of the radial shovel as well as the course of the lower or leading edge of the conveyor shovel are selected such that contact with the pile core is always avoided. Thus, the radial shovel overlaps the adjacent central chisel in the conveying direction.

[0030] The inner ring plate can advantageously perform a number of functions in accordance with the principles of the invention: the underside of the inner ring plate can be provided with mounting holes for receiving a central chisel and / or a radial shovel and / or a receiving opening for receiving a mounting part or a drill chuck which serves to releasably hold the central drill unit, the drill chuck for example comprising a locking part which allows the central drill unit to be fixed in the drill chuck and released again if required.

[0031] An upper side of the inner ring plate may have a receiving opening for receiving a shaft that connects the inner ring plate to the coupling device.

[0032] The connection of the attachments or drill chucks and shafts to the inner ring plate can be made by known mechanical connection techniques, such as press-fitting and / or threading. For mounting the central chisel, a holder is preferably provided which is inserted into the mounting hole. The central chisel and the central drill unit can thus be advantageously connected to the inner ring plate and thus maintenance operations can be advantageously carried out. No welding operations are required in case of malfunction or when maintenance is required. Instead, the central chisel and the central drill unit can be easily removed and replaced.

[0033] In a further preferred embodiment, the central chisels are radially spaced from each other on the circular line or work circle with equal or unequal chisel spacing, whereby the uniform or different chisel spacing between the work circles is preferably in the range of 20 mm to 40 mm.

[0034] During the movement or rotation of the cutting head around the axis of rotation, the central chisels preferably extend in pairs diametrically opposite each other in the same working circle spaced apart from each other. By radially spacing the central chisels or working circles in the range of 20mm to 40mm, a particularly efficient removal of material of the pile core is achieved. If the distance is more than 40mm, too little material is removed, and if the distance is less than 20mm, penetration of the central chisel is only possible with rather large forces, which is preferably avoided to prevent damage to the pile head and the cutting head. Ideally, the chisel spacing is in the range of 25mm to 35mm.

[0035] The inner ring plate is preferably offset forward in the cutting direction relative to the outer ring plate such that the central chisel is also offset forward relative to the ring chisel, for example there is an axial displacement of 10 mm to 25 mm.

[0036] Alternatively or additionally, the mounting height of the central chisel in the cutting direction is preferably in the range of 5 mm to 25 mm and varies from working circle to working circle with an increasing height difference in the direction of the rotation axis.

[0037] Thus, during the operation of the cutting head, the central drill unit penetrates the pile core first. Then, the central chisels penetrate the pile core in pairs in sequential steps, so as to machine the pile core from the inside to the outside. Thus, the surface tension of the pile core is gradually broken by the gradual arrangement of the central chisels. Instead of breaking the surface of the pile core in one step, the surface tension is broken in steps, and therefore with reduced force. Thus, the cutting head of the present invention can operate efficiently with reduced force or reduced driving torque.

[0038] In another preferred embodiment, the mounting heights of the ring chisels in the cutting direction are also selected to be different. Preferably, the mounting height in the cutting direction increases radially outward in stages from ring chisel to ring chisel or from working circle of the ring chisels to working circle with a height difference preferably in the range of 5 mm to 25 mm.

[0039] The ring chisel located at the outermost edge of the outer ring plate is displaced furthest downward in the cutting direction relative to the pile head, so that the outermost edge of the pile jacket is cut first. Therefore, the pile jacket is cut from the outside to the inside, avoiding tearing. Thus, the surface tension of the pile jacket is broken at the outer edge, and then the pile jacket is gradually removed inwards.

[0040] The central chisels and the ring chisels are preferably attached in at least two helical rows on the underside of the inner and outer ring plates, respectively. The chisel height of the central chisels preferably increases sequentially from central chisel to central chisel, either linearly or non-linearly, in the direction of the axis of rotation or radially inward of the central drill unit, as described. On the other hand, the chisel height of the ring chisels preferably increases sequentially from ring chisel to ring chisel, either linearly or non-linearly, in the radially outward direction to the edge of the outer ring plate, as described.

[0041] The central drill unit and the central chisel at different mounting heights as well as the ring chisels at different mounting heights form, in their engagement area or corresponding working circle, a corrugation extending concentrically to the axis of rotation, which has a maximum value in the area of ​​the axis of rotation in the cutting direction, a minimum value in the area of ​​the central circular ring surface and rises again towards the outer edge of the outer ring plate in the cutting direction. The corrugation ensures an optimal engagement of the cutting head in the pile head and therefore allows efficient but gentle machining. The surface tension in the pile core and in the pile jacket is advantageously broken, so that a rapid material removal with reduced energy requirements is performed and at the same time damage such as tearing of the pile jacket is avoided. The invention thus combines these three essential advantages, which are usually mutually exclusive. A reduced energy input results in a faster and more gentle material removal. It is noted that the cutting process is favored on the one hand by the inventive disposal of the cutting material and on the other hand by the advantageous arrangement of the central chisel and / or the ring chisel.

[0042] At least one conveyor shovel has a leading edge extending from an inner edge closer to the axis of rotation to an outer edge further from the axis of rotation. The conveyor shovel or shovels are arranged and aligned such that contact with the pile head is avoided and the loosened cutting material is firmly gripped and efficiently transferred to the associated conveyor spiral. The cut material conveyed radially outward from the radial shovel to the transfer opening is collected by the conveyor shovel and conveyed upwards to the conveyor spiral. On the other hand, the cut material loosened by the outer central chisel is first collected outward by the conveyor shovel and transferred to a material flow extending inward and upwards towards the conveyor spiral. This prevents the cut material from being collected around the inner ring plate and interfering with the cutting process or the rotation of the cutting head. The conveyor shovel is preferably provided with an outer shovel wall so that the material collected by the conveyor shovel is not thrown outward by centrifugal force.

[0043] Thus, in a preferred embodiment, at least one clearing tool, e.g. a chisel, is further provided which grips material around the periphery of the inner ring plate and deflects the inner ring plate inwards. The clearing tool or chisel preferably projects radially outwards beyond the inner ring plate by a gap width preferably in the range of 5mm to 40mm.

[0044] Preferably, the leading edge of the conveyor shovel is inclined horizontally to the diameter of the inner ring plate by a horizontal inclination angle so that the outer edge of each conveyor shovel leads and the inner edge follows as the cutting head rotates in the working direction. The horizontal inclination angle, preferably in the range of 5°-25°, ensures that the cutting material is gripped at the periphery and guided towards the center of the conveyor shovel.

[0045] Preferably, the leading edge of the conveyor shovel is inclined perpendicularly to the diameter of the inner ring plate by a vertical inclination angle so that the inner edge is higher than the outer edge, preferably according to the course of the assembly height of the central chisel. The vertical inclination angle is preferably selected according to the height of the central chisel so that between the tip of the central chisel and the leading edge of the conveyor shovel there is a shovel spacing or distance in the range of 5 mm to 40 mm from the chisel tip and therefore from the surface of the pile core.

[0046] The conveyor shovel is further inclined at a vertical inclination angle of the shovel relative to the axis of rotation, such that the leading edge of the conveyor shovel leads during operation of the cutting head, the vertical inclination angle of the shovel being preferably in the range of 5° to 85°.

[0047] The at least one radial shovel and / or the at least one conveyor shovel are preferably at least partially form-fitted into recesses or mounting holes provided in the inner ring plate. In this way, the radial shovel and the conveyor shovel can be easily mounted and removed. On the other hand, the at least one radial shovel and / or the at least one conveyor shovel can also be fully or partially welded to the inner ring plate, which preferably allows the radial shovel and the conveyor shovel to be at least partially flat against the support surface of the inner ring plate.

[0048] The central chisel provided on the central milling cutter and the ring chisel provided on the ring milling cutter preferably comprise a weldable or form-fitting mount and a chisel element that can be inserted therein and can be routinely replaced. Preferably, the holder is connected to a corresponding holder or mounting element of the ring plate by a form-fitting connection, for example a dovetail connection. The ring chisel is preferably slightly larger than the central chisel. Furthermore, one of the ring chisels can be connected to the inner ring plate as a clearing chisel.

[0049] The inner and outer diameters of the inner and outer ring plates are preferably precisely adapted to the dimensions of the pile and the position of the armouring within the pile, thereby ensuring maximum removal of concrete without damaging the armouring. The cutting head is therefore provided according to the dimensions of the pile head to be machined, which can have an outer diameter of more than 2m.

[0050] Preferably, central milling cutters and ring milling cutters of any size can be combined with each other or connected to each other by connecting plates. Furthermore, outer ring plates of different sizes and / or with different tools can be preferably releasably connected to the mounting cylinder. Furthermore, inner ring plates of different sizes and / or with different tools can be preferably releasably connected to the shaft. In this way, the cutting head can be flexibly adapted to the pile head to be machined.

[0051] The cutting head is made of a resistant material, in particular steel. The tool parts that come into contact with the concrete pile are preferably made of hard metal. Typically, the cutting tool comprises a receiving opening into which the carbide elements are inserted to machine the concrete. The use of plastic parts is possible if these have the desired strength and, for example, give the cutting head or its parts a certain elasticity.

[0052] The present invention will now be described in more detail with reference to the drawings. [Brief description of the drawings]

[0053] [Figure 1a]FIG. 1 is a cross-sectional view of a cutting head 1 of the present invention for machining a pile head 80, comprising a coupling device 13, a ring milling cutter 12 with a number of ring chisels 12 attached to the underside of an outer ring plate 122, and a central milling cutter 11 with an inner ring plate 112, the underside of which is provided with a number of central chisels 111, and two conveyor shovels 119A, 119B are attached adjacent to transfer openings 1120A, 1120B through which loosened cutting material can be transported from the working area of ​​the central chisels 111 to the conveyor spirals 113A, 113B. [Figure 1b] FIG. 1b shows the cutting head 1 of FIG. 1a during machining of the pile head 80, whose pile core 81 and pile jacket 82, between which the intact iron armor 83 is held in a relatively thin concrete sleeve 88, have already been removed at height h2. [Diagram 2] 1a shows the cutting head 1 from FIG. 1b, seen from below, with the inner ring plate 112 with the central chisel 111 and the outer ring plate 122 with the ring chisel 121, which, depending on the geometric shape of the cut pile 8, cover the central circular ring area kr1 corresponding to the pile core 81 and the outer circular ring area kr3 corresponding to the pile jacket 82, and define the intermediate circular ring area kr2, into which the concrete sleeve 88 with the iron armoring 83 remaining after machining of the pile head 80 can enter. [Figure 3a] FIG. 3 shows the inner ring plate 112 of FIG. 2 with two series 111A, 111B of spirally arranged central chisels 111 and a central drill unit 114, with two transfer openings 1120A, 1120B, each laterally flanked by a radial shovel 118A, 118B, in the rearward rotation direction by a conveyor shovel 119A, 119B, each of which is provided in front of a clearing chisel 1119A, 1119B. [Figure 3b]3a shows the inner ring plate 112 with marked working circles ml of two series 111A, 111B of two central chisels 111 diametrically opposed to each other with respect to the respective rotation axis x of the cutting head 1 and the central drill unit 114, guided along a common working circle ml. [Figure 4] FIG. 1 shows a portion of a central milling cutter 11 having an inner ring plate 112, a central drill unit 114, only three attached central chisels 1112A, 1115B, 1118A, and one of the transfer openings 1120B flanked by an associated radial shovel 118B and an associated conveyor shovel 119B protruding into the working area of ​​the central chisel 111. [Figure 5a] FIG. 3B shows a spatial representation of the inner ring plate 112 of FIG. 3a complete with central chisel 111, radial shovels 118A, 118B, conveyor shovels 119A, 119B, clearing tools 1119A, 1119B and central drill unit 114. [Figure 5b] 5a after removal of the central chisel 111 and the conveyor shovel 119B, and after removal of the central drill unit 114 together with the drill chuck 1143 from the recess 1129 of the inner ring plate 112. FIG. [Figure 6a] 5a from above with conveyor spirals 113A, 113B adjacent to the upper side of the inner ring plate 112, which are rotated 180° relative to each other around the shaft 115 of the central milling cutter 11 and in this section each provided with a spiral wall 1130, and also a transfer opening 1120B, in front view, adjacent below by a conveyor shovel 119B protruding into the working area of ​​the central chisel 111 and adjacent above by the conveyor spiral 113B. [Figure 6b] FIG. 6b shows the inner ring plate 112 of FIG. 6a with transfer openings 1120A, 1120B and without the conveyor spirals 113A, 113B, shaft 115 and conveyor shovel 119B. [Figure 7a] FIG. 1 shows a central chisel 111 with a holder 111F and a chisel element 111M inserted therein. [Figure 7b] FIG. 1 shows a ring chisel 121 with a holder 121F and a chisel element 121M inserted therein.

[0054] FIG. 1a shows a cross-sectional view of a cutting head 1 of the invention designed to machine a pile head 80 of a concrete pile 8, as shown in FIG. 1b.

[0055] The cutting head 1 comprises a central milling cutter 11 and a ring milling cutter 12, which are connected to each other at their upper side by a connecting plate 133 and a counter plate 134 and to a coupling device 13. The coupling device 13 comprises a coupling sleeve 131, into which a drive shaft 2 of a drive (not shown) can be inserted and locked by means of a bolt 132. The drive shaft 2 is held, for example, by a construction vehicle, which can rotate and axially displace the drive shaft 2 about the rotation axis x of the cutting head 1 or about the longitudinal axis. The cutting head 1 can thus be rotatably lowered coaxially onto the pile head 80 for machining, as shown in FIG. 1b. In all embodiments, the cutting head 1 is rotated clockwise as viewed from above.

[0056] The ring milling cutter 12 comprises an outer ring plate 122, on the underside of which the ring chisel 121 is attached aligned with the direction of rotation or inclined relative to the direction of rotation. The upper side of the outer ring plate 122 is releasably connected to the underside of the mounting cylinder 123, preferably by means of, for example, flange elements and screws or threaded elements, and its upper side is releasably connected to the connecting plate 133, preferably by means of, for example, flange elements and screws or threaded elements. The mounting cylinder 123 is shown in a quarter cross section to expose the view of the central milling cutter 11. On the underside, the mounting cylinder 123 comprises an outlet window 1231 through which the loosened cutting material can be guided outwards. On the upper side, the mounting cylinder 123 comprises a mounting window 1232 which allows engagement with a cutting head 1, for example to release the central milling cutter 11.

[0057] The central milling cutter 11 comprises an inner ring plate 112, on the underside of which a central chisel 111 is attached aligned in the direction of rotation or inclined to the direction of rotation. A central drill unit 114 is provided on the underside of the inner ring plate 112, aligned coaxially with the axis of rotation x and protruding downwards in the cutting direction beyond the central chisel 111 and the ring chisel 121. The inner ring plate 112 further comprises two transfer openings 1020A, 1020B (see FIG. 3a), which are diametrically opposed to each other with respect to the axis of rotation x and to which the radial shovels 118A, 118B and the conveyor shovels 119A, 119B are respectively assigned.

[0058] At the upper side, a conveyor spiral 113A, 113B adjoins each of the transfer openings 1020A, 1020B. The conveyor spirals 113A, 113B, which surround the shaft 115 upwards, are preferably made of solid metal sheets. The lower side of the shaft 115 is connected to the inner ring plate 112 and is preferably releasably held at the upper side by a connecting device 14. The shaft 115 is connected to the coupling device 13 in a force-locking and / or form-locking manner by the connecting device 14. The connecting device 14 preferably comprises clamping devices distributed along the circumference of the shaft 115, which allow the shaft 115 to be clamped to the counter plate 134. The connecting device 14 thus allows the shaft 115, and thus the central milling cutter 11, to be removed from the cutting head 1. The central milling cutter 11 can thus be removed, repaired, reinserted or replaced by a central milling cutter 11 with other features.

[0059] FIG. 1b shows the cutting head 1 of FIG. 1a during machining of the pile head 80 of the pile 8 shown cut open, with height h1 and diameter d. The pile core 81 and pile jacket 82, between which the undamaged iron armoring 83 is held in a relatively thin concrete sleeve 88, have already been removed over a height difference h2 from top to bottom. The loosened cutting material is collected by the conveyor shovels 119A, 119B and fed through the transfer openings 1220A, 1220B to the conveyor spirals 113A, 113B, where it is lifted and carried away by the conveyor spirals 113A, 113B above the pile head 80 and the remaining concrete sleeve 88, respectively. Inside the pile head 80, the cut material is laterally held by a spiral wall 1130 formed or welded around the conveyor spirals 113A, 113B. The cutting material is thus lifted above the pile head 80 and only afterwards is it discharged outwards into the outlet opening 1231 of the mounting cylinder 123 under the influence of centrifugal force.

[0060] FIG. 1b further shows that the central chisels 111 and the ring chisels 121 are at different heights and therefore engage the pile head 80 at different depths. At least the central chisels 111 close to the central drill units 114 are all lower in the cutting direction than the ring chisels 121. Also, on the inner ring plate 112 and on the outer ring plate 122, the central chisels 111 and the ring chisels 121 are mounted at different heights in the cutting direction. The mounting height of the central chisels 111 increases radially in the direction of the rotation axis x, preferably in stages between the central chisels 111. The mounting height of the ring chisels 121 increases radially outward, preferably in stages between the ring chisels 121. It is possible to provide a linear or non-linear increase. The central drill units 114 themselves, which take on a guiding or piloting function, protrude downwards beyond the central chisels 111.

[0061] FIG. 1b shows a cross-sectional view of the pile head 8 with a symmetrical course of the cutting line dl, which, corresponding to the arrangement of the central drill unit 114, the central chisel 111 and the ring chisel 121, includes a maximum value in the region of the rotation axis, is interrupted and includes a minimum value in the region of the concrete sleeve 88 or the central circular ring region kr2, and then rises again outward in the cutting direction. When the pile head 8 is machined, a corresponding corrugation, concentric with respect to the rotation axis x, arises on its surface. This corrugation ensures that the central milling cutter 11 and the ring milling cutter 12 optimally engage the pile head 80, moving the pile core 81 from the inside to the outside and the pile jacket 82 from the outside to the inside. This gradual machining of the pile head 80 allows advantageously releasing the surface tension in the pile core 81 and in the pile jacket 82, while avoiding damage to the pile head 80.

[0062] After machining of the pile head 80 has been completed, the cutting head 1 is lifted again. The remaining concrete sleeve 88, which still surrounds and protects the iron armoring 83, is then removed with little effort using other tools such as cutting and clamping.

[0063] 2 shows the cutting head 1 seen from below with the inner ring plate 112 with the central chisel 111 and the outer ring plate 122 with the ring chisel 121 which, depending on the geometry of the cut pile 8, cover the central circular ring area kr1 corresponding to the pile core 81 and the outer circular ring area kr3 corresponding to the pile jacket 82 and define the intermediate circular ring area kr2 into which the concrete sleeve 88 with the iron armoring 83 remaining after machining of the pile head 80 can be placed. A part of the intermediate circular ring area kr2 is shown hatched.

[0064] The outer ring plate 122 has an outer diameter d122o and an inner diameter d122i. The inner ring plate 112 has an outer diameter d112.

[0065] On the outer ring plate 122, three series 121A, 121B, 121C of twelve spirally arranged ring chisels 121 or 1211, 1212, ..., 12112 are arranged offset by 120° from each other. Each of the three ring chisels 121 follows the same working circle ml (only one working circle ml is shown). The mounting height of the ring chisels 121 preferably increases continuously from the first ring chisel 1211 to the last ring chisel 12112 or from one working circle ml to the next, radially from inside to outside, so that the outermost ring chisel 12112 is located highest in the cutting direction and thus grips the outer edge of the pile jacket 82 first. In this way, the pile jacket 82 is machined from outside to inside, thus avoiding harmful tearing. The increase in mounting height of the ring chisels 121 is preferably in the range of 5 mm to 25 mm. For example, the increase in mounting height of the first ring chisel 1211, 1212, ... is close to 5 mm, and the increase in mounting height of the last ring chisel ..., 12111, 12112 is close to 25 mm.

[0066] On the inner ring plate 112, shown larger in FIG. 3a, eight helically arranged central chisels 111 and two series 111A, 111B of 1111, 1112, ..., 1118 are arranged, offset by 180° from each other.

[0067] As Fig. 3b shows, the two diametrically opposite central chisels 111 follow the same working circle ml. The mounting height of the central chisels 111 preferably increases continuously from the first central chisel 1111 to the last central chisel 1108 radially from the outside to the inside, so that the central chisel 1108 closest to the axis of rotation x is located highest in the cutting direction and thus penetrates first into the center of the pile core 81 after the central drill unit 114. In this way, the pile core 81 is machined from the inside to the outside, so that it is possible to machine the pile core 81 more quickly.

[0068] For example, the increase in mounting height of the first ring chisels 1111, 1112, ... is close to 5 mm, and the increase in mounting height of the last ring chisels ..., 1107, 1108 is close to 25 mm.

[0069] The central chisels 111 are radially offset from one another in pairs with equal or unequal chisel distances ma and define working circles ml during rotation. The difference in the radii of the working circles ml corresponds to the respective chisel spacing. The uniform chisel spacing ma or the different chisel distances ma are preferably in the range of 20 mm to 40 mm. This arrangement of the central chisels 111 ensures optimal removal of material. The working circles ml are therefore radially and also vertically offset from one another.

[0070] The inner ring plate 112 also comprises two transfer openings 1120A, 1120B diametrically opposite each other with respect to the axis of rotation x, through which the loosened cut material can be guided. To remove the cut material, a conveyor shovel 119A, 119B is provided adjacent to the rear edge of each of the transfer openings 1120A, 1120B, which on the one hand extends partially into the area of ​​the respective transfer opening 1120A, 1120B and on the other hand extends partially into the working area of ​​the central chisel 111. At the front, the conveyor shovel 119A, 119B comprises a leading edge 1193 which extends from the inner edge to the outer edge of the conveyor shovel 119A, 119B. Thus, the leading edge 1193 of the conveyor shovel 119A, 119B first engages the exposed cut material in order to guide it upwards away through the conveyor shovel 119A, 119B.

[0071] FIG. 3a shows that the leading edge 1193 is inclined horizontally with respect to the diameter d112 of the inner ring plate 112 by a horizontal inclination angle a1, such that the outer edge 1192 of the respective conveyor shovel 119A, 119B leads and the inner edge 1191 follows as the cutting head 1 rotates in the working direction. Thus, the cutting material is first captured outside the leading edge 1193 and displaced inwards with respect to the corresponding transfer opening 1120A, 1120B. The displacement of the cut material results in a favorable material flow that reduces the load on the conveyor shovels 119A, 119B. The horizontal inclination angle or leading angle a1 is preferably in the range of 0°-25°.

[0072] Each of the transfer openings 1120A, 1120B is also associated with a radial shovel 118A, 118B that conveys cut material exposed by the central drill unit 114 and inner central chisel 111 outwardly to the transfer openings 1120A, 1120B. The radial shovels 118A, 118B may be simple plates that are preferably form-fittingly held by the inner ring plate 112 and are preferably radially or angled towards the associated transfer opening 1120A, 1120B.

[0073] Figure 3b further shows that a clearing chisel 1119A, 1119B is attached to the front edge of each of the transfer openings 1120A, 1120B, which protrudes outward beyond the inner ring plate 112 by a gap width b, which is preferably in the range of 5 mm to 40 mm. The clearing chisels 1119A, 1119B pick up concrete particles that are not yet loosened and may damage the conveyor shovels 119A, 119B, as well as the cutting material that is on the outside, and transport the cutting material radially inwards so that it can be picked up by the conveyor shovels 119A, 119B. The clearing chisels 1119A, 1119B are preferably identical to the ring chisel 121, which is preferably larger than the central chisel 111.

[0074] To ensure that the cut material can be sufficiently gripped around, the conveyor shovels 119A, 119B may also protrude radially outwardly beyond the inner ring plate 112 by a maximum of 35 mm.

[0075] FIG. 3b further shows that the inner ring plate 112 has a mounting hole 1128 on its underside into which the central chisel 111 or a holder for the central chisel 111 is inserted.

[0076] 4 shows a part of a central milling cutter 11 with an inner ring plate 112, a central drilling unit 114, only three attached central chisels 1112A, 1115B, 1118A, and one of the transfer openings 1120B flanked by associated radial shovels 118B and associated conveyor shovels 119B extending into the working area of ​​the central chisel 111. For each of these tools, the penetration depth is shown: for the central drilling unit 114, penetration depth t0; for the central chisels 1112A, 1115B, 1118A, penetration depths t1, t2, t3; for the inner and outer edges 1181 and 1182 of the radial shovels 118B, penetration depths t1181, t1182; for the inner and outer edges 1191 and 1192 of the conveyor shovels 119B, penetration depths t1191, 1192.

[0077] The leading edge 1183 of the radial shovel 118B extends downwardly from the inner edge 1181 to the outer edge 1182, or from the penetration depth t1181 to the penetration depth t1182. The leading edge 1193 of the conveyor shovel 119B extends downwardly from the inner edge 1191 to the outer edge 1192, or from the penetration depth t1191 to the penetration depth t1182.

[0078] The front edge 1193 of the conveyor shovel 119B is preferably inclined perpendicularly to the diameter d112 of the inner ring plate 112 by a vertical inclination angle a2 so that the inner edge 1191 is higher than the outer edge 1192 in the conveying direction, preferably according to the course of the mounting height of the central chisel 111. Thus, the conveyor shovel 119B cannot come into contact with the surface of the pile head 80 or the pile core 81.

[0079] Preferably, a shovel gap a3 is provided between the leading edge 1193 of the conveyor shovel 119 and the working circle ml of the central chisel 111 or the tip of the central chisel 111, which is preferably in the range of 5 mm to 40 mm.

[0080] FIG. 4 further shows that a central drill unit 114 comprising a cutting or drilling tool 1141 and a tool shaft 1142 is held in a mounting or drill chuck 1143 and secured by a locking portion 11431, for example by a bolt.

[0081] Figure 5a shows a spatial representation of the inner ring plate 112 of figure 3a complete with the central chisels 111, radial shovels 118A, 118B, conveyor shovels 119A, 119B, clearing tools 1119A, 1119B and the central drill unit 114. A series of central chisels 111 are marked with corresponding sequence numbers 1111, 1112, ..., 1108. Furthermore, a top view of the conveyor shovel 119B through the transfer opening 1120B is shown on the right side.

[0082] Figure 5b shows the inner ring plate 112 of figure 5a after removal of the central chisel 111 and the conveyor shovel 119B, as well as after removal of the central drill unit 114 together with the drill chuck 1143 from the recess 1129 of the inner ring plate 112. Furthermore, on the underside of the inner ring plate 112, the recess 1123 serving to accommodate the radial shovels 118A, 118B is visible. The housing 121F of the clearing chisel 1119B is still attached.

[0083] To achieve the assembly height or mutual vertical displacement of the central chisels 111, the underside of the inner ring plate 112 is provided with ring-shaped steps S1, S2, S3, S4, S5, which preferably correspond to the working circle ml.

[0084] Figure 6a shows the inner ring plate 112 of Figure 5a from above with conveyor spirals 113A, 113B adjacent to the upper side of the inner ring plate 112, rotated 180° relative to each other, surrounding the shaft 115 of the central milling cutter 11 and each provided with a spiral wall 1130 in this section. A transfer opening 1120B is shown, adjacent on the lower side to a conveying bucket 119B projecting into the working area of ​​the central chisel 111 and adjacent on the upper side to a conveying spiral 113B. The inner ring plate 112 has a transfer surface 1125A, 1125B for each of the transfer openings 1020A, 1020B, through which the cutting material is conveyed from the conveyor shovel 119A, 119B to the associated conveyor spiral 113A, 113B. It is possible for this transfer surface 1125A, 1125B to be completely covered by the conveyor shovel 119A, 119B. Thus, the conveyor shovel 119A, 119B can for example be welded to the lower end of the transfer surface 1125A, 1125B at the front or can be attached or screwed to the associated transfer surface 1125A, 1125B.

[0085] The conveyor shovel 119B is adjacent to or extends further below the transfer opening 1120B and is inclined by the inclination angle of the shovel a4 relative to the axis of rotation x, forming an inclined surface. The inclination angle of the shovel a4, at which the conveyor shovel 119B is inclined below the transfer opening 1120B with its leading edge 1193 forward, is preferably in the range of 5° to 85°. Preferably, a vertical orientation of the conveyor shovel 119B is avoided and the cutting material is pushed forward and is barely displaced upwards. The inclination angle of the shovel a4, which is about 45° in the illustrated embodiment, is therefore selected so that the cut material can pass beyond the conveyor shovel 119B onto the transfer opening 1020B and the conveyor spiral 113B. To prevent the conveyed cutting material from escaping to the outside, the conveyor shovel 119B is provided with an outer wall 1195.

[0086] The transfer surface 1125B is preferably shaped to provide an unobstructed, preferably laminar, transition between the conveyor shovels 119B at the entrance of the conveyor spiral 113B.

[0087] Figure 6b shows the inner ring plate 112 of Figure 6a without the conveyor spirals 113A, 113B, the shaft 115 and the conveyor shovel 119B. After removing the conveyor shovel 119B, the connection space with the connection surface 1127 is exposed at the lower edge of the transfer surface 1125B or at the underside of the transfer opening 1120B, where the conveyor shovel 119B can be fastened, for example screwed and / or welded. Also exposed are the connection surfaces 1126A, 1126B for the conveyor spirals 113A, 113B, which extend to an edge or stop 11261 that is flush with the upper edge of the associated conveyor spiral 113A, 113B, so that the cutting material can enter the conveyor spirals 113A, 113B without hindrance.

[0088] FIG. 7a shows a central chisel 111 with a holder 111F and a chisel element 111M inserted therein.

[0089] Figure 7b shows a ring chisel 121 with a holder 121F and a chisel element 121M inserted therein. In this embodiment, the ring chisel 121 is also used as a clearing chisel, as shown in figure 6b. [Explanation of symbols]

[0090] 1 Cutting head 11 Central milling cutter 111,1111,…,1118 central chisel 111A,111B Central chisel group 111F Chisel Holder 111M Chisel or tool 1119A, 1119B Clearing tool, clearing chisel 112 Inner ring plate 1120A,1120B Transfer opening Mounting holes for 1123 radial excavators 1124 Receiving opening for shaft 115 1125A, 1125B Transfer surface of transfer opening Connection surface for 1126A, 1126B conveyor spirals 1127 Connection surface for conveyor excavator 1128 Mounting hole for central chisel 111 1129 Receiving opening for mounting part 1143 113A, 113B Conveyor spiral 1130 spiral wall 114 Central Drill Unit 1141 Cutting tools, hard metal cutting edges 1142 Tool shaft 1143 Mounting part, drill chuck 11431 Lock section 115 Shaft 118A, 118B Radial shovel 1181 Radial shovel inner edge 1182 Radial Shovel Outer Edge 1183 Radial Shovel Front Edge 119A, 119B Conveyor shovel 1191 Inner edge of conveyor shovel 1192 Outer edge of conveyor shovel 1193 Front edge of conveyor shovel 1195 Conveyor Excavator Outer Wall 12 Ring milling cutter 121;1211,…,12112 Ring chisel 121A,…,121C Ring chisel group 121F Chisel Holder 121M Chisel or tool 122 Outer ring plate 123 Mounting cylinder 1231 Exit window 1232 Access mounting window 13 Coupling device 131 Connecting sleeve 132 Connecting means, connecting bolts 133 Connecting plate 134 Opposing Plate 14 Connecting Devices 2 Drive shaft 8 Pile 81 Pile Core 82 Pile jacket 83 Metal exterior 88 Concrete Sleeve a1 Horizontal inclination angle of leading edge a2 Vertical inclination angle of leading edge a3 Shovel spacing a4 Excavator inclination angle b Gap width d pile diameter d112 Outside diameter of inner ring plate d122i Inner diameter of outer ring plate d122o Outer ring plate outer diameter dl Cutting line along pile diameter h1 pile height h2 Pile head height kr1, central circular ring region kr2 Mid-circular ring region kr3 outer circular ring region ma Chisel Spacing ml Chisel line, working circle S1, ..., S5 Steps in the inner ring plate 112 t0 Penetration depth of central drill unit t1 Penetration depth of central chisel 1118A t2 Penetration depth of central chisel 1115B t3 Penetration depth of central chisel 1112A T1181 Penetration depth inner edge radial shovel T1182 Penetration Depth Outer Edge Radial Shovel T1191 Penetration depth inner edge conveyor shovel T1192 Penetration Depth Outer Edge Conveyor Shovel

Claims

1. A cutting head (1) for machining a pile head (80) of a pile (8) having an axis of rotation (x) and comprising a pile core (81), a pile jacket (82) and a metal sheath (83) interposed therebetween, said cutting head (1) having an axis of rotation (x) and a coupling device (13) connectable to a drive shaft (2) of a drive device; A central milling cutter (11) having a plurality of central chisels (111) attached to the underside of an inner ring plate (112); having the inner ring plate (112) comprises at least one transfer opening (1120A, 1120B) leading from the lower side to the upper side of the inner ring plate (112), the at least one transfer opening (1120A, 1120B) being bordered on the lower side by a conveyor shovel (119A, 119B) which at least partially projects into the working area of ​​the central chisel (111), and the at least one transfer opening (1120A, 1120B) being bordered on the upper side by a conveyor spiral (113A, 113B), Cutting head (1).

2. A ring milling cutter (12) having a plurality of ring chisels (121) attached to the underside of an outer ring plate (122), The central milling cutter (11) and the ring milling cutter (12) are connected to each other in coaxial alignment with the axis of rotation (x); 2. The cutting head (1) according to claim 1, characterized in that said outer ring plate (122) surrounds said inner ring plate (112) separated by a middle circular ring area (kr2) thereof.

3. 3. The cutting head (1) according to claim 1 or 2, characterized in that the inner ring plate (112) comprises two transfer openings (1120A, 1120B), each of which is bordered on the lower side by a conveyor shovel (119A; 119B) protruding at least partially into the working area of ​​the central chisel (111) and each of which is bordered on the upper side by a conveyor spiral (113A; 113B).

4. 4. The cutting head (1) according to claim 1, 2 or 3, characterized in that the transfer openings (1120A, 1120B) and the conveyor shovels (119A, 119B) as well as the central chisel (111) are diametrically opposed to each other in pairs with respect to the axis of rotation (x) and are equidistant from the axis of rotation (x).

5. 5. The cutting head (1) according to any one of claims 1 to 4, characterized in that the inner ring plate (112) is connected to the underside of a shaft (115) and the outer ring plate (122) is connected to the underside of a mounting cylinder (123), the shaft (115) and the mounting cylinder (123) being connected to a connecting plate (133) coaxially aligned with the axis of rotation (x) and above which the coupling device (13) is arranged.

6. A cutting head (1) according to any one of claims 1 to 5, characterised in that the at least one conveyor spiral (113A; 113B) or two conveyor spirals (113A; 113B), preferably rotated by 180° relative to each other, are provided with a side wall (1130) in their lower section, preferably selected depending on the height of the pile head (80) to be machined.

7. 7. The cutting head (1) according to any one of claims 1 to 6, characterized in that a central drill unit (114) is arranged on the underside of the inner ring plate (112), is coaxially aligned with the axis of rotation (x) and projects beyond the central chisel (111) and the ring chisel (121) in a cutting direction, and at least one radial shovel (118A, 118B) is provided on the underside of the inner ring plate (112), the shovel (118A, 118B) being adjacent to the central drill unit (114) and preferably radially aligned with respect to the axis of rotation (x).

8. A cutting head (1) according to any one of claims 1 to 7, characterized in that the central drill unit (114) is releasably held in a mounting or drill chuck inserted into a receiving opening (1129) in the underside of the inner ring plate (112).

9. A cutting head (1) according to any one of the preceding claims, characterized in that said central chisels (111) are each radially offset from one another with equal or unequal chisel spacings (ma) and define a working circle (ml) during rotation, said uniform chisel spacing (ma) or said different chisel spacings (ma) of said central chisels (111) or the radial spacing of said working circles (ml) preferably being in the range of 20 mm to 40 mm.

10. 10. The cutting head (1) according to any one of claims 1 to 9, characterized in that said central chisels (111) are each radially spaced apart on a working circle (ml) with equal or unequal chisel distances (ma), the mounting height of said central chisels (111) in the cutting direction preferably being in the range of 5 mm to 25 mm and varying from one working circle (ml) to the next by an increasing height difference in the direction of said rotation axis (x).

11. A cutting head (1) according to any one of claims 1 to 10, characterised in that the ring chisels (121) are each radially offset from one another with equal or unequal chisel spacings and define working circles (ml) during rotation, the mounting height of the ring chisels (121) increasing radially outwardly in the cutting direction from one working circle (ml) to the next by a height difference preferably lying in the range of 5 mm to 25 mm.

12. 12. The cutting head (1) according to claim 1, characterized in that the central drill unit (114) and the central chisel (111) and the ring chisels (121) at different mounting heights form, in their engagement area or in their working circle (ml), a corrugation extending concentrically to the axis of rotation (x), said corrugation having a maximum value in the area of ​​the axis of rotation (x) in the cutting direction, a minimum value in the area of ​​the central circular ring area (kr2) and rising again in the cutting direction towards the outer edge of the outer ring plate (122).

13. The cutting head (1) according to any one of claims 1 to 12, characterized in that the at least one conveyor shovel (119A, 119B) comprises a leading edge (1193) extending from an inner edge (1191) closer to the axis of rotation (x) to an outer edge (1192) further from the axis of rotation (x), the leading edge (1193) being horizontally inclined with respect to the diameter (d112) of the inner ring plate (112) by a horizontal inclination angle (a1) such that the outer edge (1192) leads and the inner edge (1191) follows during a rotation of the cutting head (1) in the working direction.

14. A cutting head (1) according to any one of claims 1 to 13, characterized in that the at least one conveyor shovel (119A, 119B) comprises a leading edge (1193) extending from an inner edge (1191) closer to the axis of rotation (x) to an outer edge (1192) further from the axis of rotation (x), the leading edge (1193) being inclined perpendicularly to the diameter (d112) of the inner ring plate (112) by a vertical inclination angle (a2) such that the inner edge (1191) is preferably higher than the outer edge (1192) according to the course of the mounting height of the central chisel (111).

15. A cutting head (1) according to any one of claims 1 to 14, characterized in that the at least one conveyor shovel (119A, 119B) has a leading edge (1193) extending from an inner edge (1191) closer to the axis of rotation (x) to an outer edge (1192) further from the axis of rotation (x), the leading edge (1193) being set back over its entire length in the cutting direction relative to the working circle (ml) of the central chisel (111) by a shovel spacing (a3) ​​preferably in the range of 5 mm to 40 mm.

16. A cutting head (1) according to any one of claims 1 to 15, characterized in that the at least one conveyor shovel (119A, 119B) is inclined relative to the axis of rotation (x) by a vertical inclination angle of the shovel (a4), the leading edge (1193) of the conveyor shovel (119A, 119B) being in a leading position, the inclination angle of the shovel (a4) being preferably in the range of 5° to 85°.

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