Milling head for machining pile heads

Abstract

A milling head, having a rotation axis and which serves for machining a pile head of a pile that includes a pile core, a pile jacket and a metal armouring interposed therebetween, includes a coupling device, connected to a drive shaft of a driving device, a central milling cutter, which includes a plurality of central chisels mounted on a lower side of an inner ring plate, and a ring milling cutter, which includes a plurality of ring chisels mounted on a lower side of an outer ring plate, which central milling cutter and ring milling cutter are connected to each other coaxially aligned with the rotation axis, and which outer ring plate surrounds the inner ring plate separated thereof by a middle circular ring area. The inner ring plate includes at least one transfer opening leading from the lower side to the upper side of the inner ring plate.

Claims

1. A milling head having a rotation axis for machining a pile head of a pile that comprises a pile core, a pile jacket and a metal armouring interposed therebetween, with a coupling device, which is connectable to a drive shaft of a driving device, with a central milling cutter, which comprises a plurality of central chisels mounted on a lower side of an inner ring plate, wherein the inner ring plate comprises at least one transfer opening leading from the lower side to an upper side of the inner ring plate, which the at least one transfer opening is adjoined on the lower side of the inner ring plate by at least one conveyor shovel projecting at least partially into a working area of the plurality of central chisels and which the at least one transfer opening is adjoined on the upper side of the inner ring plate by at least one conveyor spiral, and wherein a central drill unit is arranged on the lower side of the inner ring plate, which is aligned coaxially to the rotation axis and projects beyond the plurality of central chisels and a plurality of ring chisels in a milling direction, and in that the at least one conveyor shovel is provided on the lower side of the inner ring plate, which the at least one conveyor shovel adjoins the central drill unit and is aligned radially with respect to the rotation axis.

2. The milling head according to claim 1, with a ring milling cutter, which comprises the plurality of ring chisels mounted on a lower side of an outer ring plate, which the central milling cutter and the ring milling cutter are connected to each other coaxially aligned with the rotation axis, and which the outer ring plate surrounds the inner ring plate separated thereof by a middle circular ring area.

3. The milling head according to claim 1, wherein the at least one transfer opening includes two transfer openings, the inner ring plate comprises the two transfer openings, each transfer opening of the two transfer openings is adjoined on the lower side of the inner ring plate by the at least one conveyor shovel projecting at least partially into the working area of the plurality of central chisels and each of which is adjoined on the upper side of the inner ring plate by the at least one conveyor spiral.

4. The milling head according to claim 1, wherein the at least one transfer opening includes a plurality of transfer openings, the at least one conveyor shovel includes a plurality of conveyor shovels, and the plurality of transfer openings, the plurality of conveyor shovels and the plurality of central chisels lie diametrically opposite each other in pairs with respect to the rotation axis and at equal distances from the rotation axis.

5. The milling head according to claim 1, wherein the inner ring plate is connected to a lower side of a shaft and an outer ring plate is connected to a lower side of a mounting cylinder, and that the shaft and the mounting cylinder are aligned coaxially to the rotation axis and are connected at their upper side to a coupling plate on which the coupling device is arranged.

6. The milling head according to claim 1, wherein, one conveyor spiral of the at least one conveyor spiral or two conveyor spirals of the at least one conveyor spiral, which are turned 180 relative to each other, is or are provided with a side wall in a lower section, which is selected according to the height of the pile head to be machined.

7. The milling head according to claim 1, wherein the central drill unit is releasably held in a mounting part or drill chuck which is inserted into a receiving aperture on the lower side of the inner ring plate.

8. The milling head according to claim 1, wherein the plurality of central chisels are each radially offset from one another either at equal radial chisel spacings in a range of 20 mm-40 mm or unequal radial chisel spacings in the range of 20 mm-40 mm.

9. The milling head according to claim 1, wherein the plurality of central chisels are each radially spaced at equal or unequal chisel distances on work circles, wherein a mounting height of the plurality of central chisels in the milling direction changes from one work circle to the next work circle by a height difference and increases in a direction of the rotation axis.

10. The milling head according to claim 1, wherein the plurality of ring chisels are each radially offset from one another at equal or unequal chisel spacings and define work circles during rotation, wherein a mounting height of the plurality of ring chisels increases radially outwards in the milling direction from one work circle to the next work circle by a height difference which lies in a range of 5 mm-25 mm.

11. The milling head according to claim 1, wherein the central drill unit, the plurality of central chisels and the plurality of ring chisels which lie at different mounting heights form in their engagement area or with work circles a waveform which runs concentrically to the rotation axis, which has a maximum mounting height in the region of the rotation axis in the milling direction, which has a minimum mounting height in the region of a central circular ring area and which rises again towards the outer edge of an outer ring plate in the milling direction.

12. The milling head according to claim 1, wherein the at least one conveyor shovel comprises a front edge which extends from an inner edge lying closer to the rotation axis to an outer edge lying farther away from the rotation axis, which front edge is inclined horizontally relative to the diameter of the inner ring plate by a horizontal inclination angle in such a way that, during the rotation of the milling head in the working direction, the outer edge precedes and the inner edge follows behind.

13. The milling head according to claim 1, wherein the at least one conveyor shovel comprises a front edge which extends from an inner edge lying closer to the rotation axis to an outer edge lying farther away from the rotation axis, which front edge is inclined vertically relative to the diameter of the inner ring plate by a vertical inclination angle in such a way that, in accordance with the course of the mounting height of the plurality of central chisels, the inner edge lies higher than the outer edge.

14. The milling head according to claim 1, wherein the at least one conveyor shovel comprises a front edge which extends from an inner edge lying closer to the rotation axis to an outer edge lying farther away from the rotation axis, which front edge is set back over the entire length by a shovel spacing in the range of 5 mm-40 mm in the milling direction relative to work circles of the plurality of central chisels.

15. The milling head according to claim 1, wherein the at least one conveyor shovel is inclined by a vertical inclination angle of the shovel relative to the rotation axis, wherein a front edge of the at least one conveyor shovel is leading and the inclination angle of the at least one conveyor shovel is in a range of 5-85.

16. The milling head according to claim 1, wherein the plurality of central chisels are each radially spaced at equal or unequal chisel distances on work circles, wherein a mounting height of the plurality of central chisels in the milling direction changes from one work circle to the next work circle by a height difference that is in a range of 5 mm-25 mm, and increases in a direction of the rotation axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Below, the invention is explained in more detail with reference to the drawings. Thereby shows:

(2) FIG. 1a a sectional view of an inventive milling head 1 for machining pile heads 80, comprising a coupling device 13, a ring milling cutter 12, which comprises a plurality of ring chisels 12 mounted on the lower side of an outer ring plate 122, and a central milling cutter 11, which comprises an inner ring plate 112, on the lower side of which inner ring plate 112 plurality of central chisels 111 are provided and two conveyor shovels 119A, 119B are mounted adjacent to transfer openings 1120A, 1120B, through which loosened milling material can be conveyed from the working area of the central chisels 111 to conveyor spirals 113A, 113B;

(3) FIG. 1b the milling head 1 of FIG. 1a during the machining of a pile head 80, whose pile core 81 and pile jacket 82, between which the undamaged iron armouring 83 is held in a relatively thin concrete sleeve 88, have already been removed at the height h2;

(4) FIG. 2 the milling head 1 of FIG. 1a from below with a view of the inner ring plate 112 equipped with the central chisels 111 and the outer ring plate 122 equipped with the ring chisels 121, which cover a central circular ring area kr1 corresponding to the pile core 81 and an outer circular ring area kr3 corresponding to the pile jacket 82 in accordance with the geometry of the machined pile 8 and delimit a middle circular ring area kr2, into which a concrete sleeve 88 with the iron armouring 83 remaining after the machining of the pile head 80 can enter;

(5) FIG. 3a the inner ring plate 112 of FIG. 2, which is equipped with two series 111A, 111B of spirally arranged central chisels 111, a central drill unit 114 and is provided with two transfer openings 1120A, 1120B, which are each adjoined laterally by a radial shovel 118A, 118B and, in the direction of rotation rearwardly, a conveyor shovel 119A, 119B and at the front of each of which a clearing chisel 1119A, 1119B is provided;

(6) FIG. 3b the inner ring plate 112 of FIG. 3a with marked work circles m1 of the two series 111A, 111B of central chisels 111, two of which, which are diametrically opposite each other with respect to the rotation axis x of the milling head 1 and the central drill unit 114, respectively, are guided along a common work circle m1;

(7) FIG. 4 a part of the central milling cutter 11 with the inner ring plate 112, the central drill unit 114, only three mounted central chisels 1112A, 1115B, 1118A and one of the transfer openings 1120B, to which the associated radial shovel 118B and the associated conveyor shovel 119B, which project into the working area of the central chisels 111, adjoin;

(8) FIG. 5a a spatial representation of the inner ring plate 112 of FIG. 3a, fully equipped with central chisels 111, radial shovels 118A, 118B, conveyor shovels 119A, 119B, clearing tools 1119A, 1119B and the central drill unit 114;

(9) FIG. 5b the inner ring plate 112 of FIG. 5a after removal of the central chisels 111 and the conveyor shovel 119B as well as the removal of the central drill unit 114 together with the drill chuck 1143 from a recess 1129 of the inner ring plate 112;

(10) FIG. 6a the inner ring plate 112 of FIG. 5a from above with the conveyor spirals 113A, 113B adjoining the upper side of the inner ring plate 112, which are turned by 180 relative to each other around the shaft 115 of the central milling cutter 11 and which are each provided in this section with a spiral wall 1130, as well as in front view the transfer opening 1120B, which is adjoined on the lower side by the conveyor shovel 119B projecting into the working area of the central chisels 111 and which is adjoined on the upper side by the conveyor spiral 113B;

(11) FIG. 6b the inner ring plate 112 of FIG. 6a with the transfer openings 1120A, 1120B and without the conveyor spirals 113A, 113B, the shaft 115 and the conveyor shovel 119B;

(12) FIG. 7a a central chisel 111 comprising a holder 111F and a chisel element 111M inserted therein; and

(13) FIG. 7b a ring chisel 121 comprising a holder 121F and a chisel element 121M inserted therein.

DETAILED DESCRIPTION OF EMBODIMENTS

(14) FIG. 1a shows a sectional view of an inventive milling head 1, which, as FIG. 1b shows, is designed for machining pile heads 80 of concrete piles 8.

(15) The milling 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 coupling 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 device (not shown) can be inserted and locked, for example, by means of a bolt 132. The drive shaft 2 is held, for example, by a construction vehicle which is able to rotate and axially displace the drive shaft 2 about a rotation axis x or about the longitudinal axis of the milling head 1. The milling head 1 can therefore be rotationally lowered coaxially onto a pile head 80 to machine it, as shown in FIG. 1b. In all embodiments, the milling head 1 is rotated clockwise as seen from above.

(16) The ring milling cutter 12 comprises an outer ring plate 122, on the lower side of which ring chisels 121 are mounted aligned in the direction of rotation or inclined thereto. The upper side of the outer ring plate 122 is preferably releasably connected, for example by means of flange elements and screws or threaded elements, to the lower side of a mounting cylinder 123, the upper side of which is preferably releasably connected, for example by means of flange elements and screws or threaded elements, to the coupling plate 133. The mounting cylinder 123 is shown with a quarter section exposing the view of the central milling cutter 11. On the lower side, the mounting cylinder 123 comprises exit windows 1231 through which loosened milling material can be guided away to the outside. On the upper side, the mounting cylinder 123 comprises mounting windows 1232, which allow engagement in the milling head 1, for example to release the central milling cutter 11.

(17) The central milling cutter 11 comprises an inner ring plate 112, on the lower side of which central chisels 111 are mounted aligned in the direction of rotation or inclined thereto. Coaxially aligned with the rotation axis x, a central drill unit 114 is provided on the lower side of the inner ring plate 112, which projects downwards in the milling direction beyond the central chisels 111 and the ring chisels 121. The inner ring plate 112 further comprises two transfer openings 1120A, 1120B (see FIG. 3a), which are diametrically opposite each other with respect to the rotation axis x, and to each of which a radial shovel 118A, 118B and a conveyor shovel 119A, 119B are assigned.

(18) On the upper side, a conveyor spiral 113A, 113B adjoins each of the transfer openings 1120A, 1120B. The conveyor spirals 113A, 113B, which upwards enclose a shaft 115, are preferably formed from a solid sheet of metal. 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 by means of the connecting device 14 in a force-locking and/or form-locking manner. 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 detached from the milling head 1. The central milling cutter 11 can therefore be detached, serviced and reinserted or replaced by a central milling cutter 11 comprising other features.

(19) FIG. 1b shows the milling head 1 of FIG. 1a while machining a pile head 80 of a pile 8 shown cut open, which comprises a height h1 and a diameter d. The pile core 81 and the pile jacket 82, between which the undamaged iron armouring 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 milling material was collected by the conveyor shovels 119A, 119B and fed through the transfer openings 1120A, 1120B to the conveyor spirals 113A, 113B and lifted and carried away by these over the pile head 80 and the remaining concrete sleeve 88 respectively. Inside the pile head 80, the milled material is held laterally by a spiral wall 1130, which is formed or welded peripherally to the conveyor spirals 113A, 113B. The milling material is therefore lifted above the pile head 80 and only then, under the effect of centrifugal force, is discharged outwards to the outlet openings 1231 of the mounting cylinder 123.

(20) FIG. 1b further shows that the central chisels 111 and the ring chisels 121 are at different heights and thus engage the pile head 80 at different depths. At least the central chisels 111, which are close to the central drill unit 114, are all lower than the ring chisels 121 in the milling direction. Also, on the inner ring plate 112 and the outer ring plate 122 the central chisels 111 and ring chisels 121 are mounted at different heights in the milling direction. The mounting height of the central chisels 111 increases radially in the direction of the rotation axis x, preferably stepwise from central chisel 111 to central chisel 111. The mounting height of the ring chisels 121 increases radially outwards preferably from ring chisel 121 to ring chisel 121 stepwise. A linear or non-linear increase can be provided. The central drill unit 114 itself, which assumes a guiding or pilot function, projects downwards beyond the central chisels 111.

(21) FIG. 1b shows a cross-section through the pile head 8 with the symmetrical course of the milling line d1, which, corresponding to the arrangement of the central drill unit 114, of the central chisels 111 and of the ring chisels 121, comprises a maximum in the area of the rotation axis, and is interrupted in the area of the concrete sleeve 88 or in the area of the central circular ring area kr2, and comprises a minimum and subsequently rises again towards the outside in the milling direction. When the pile head 8 is machined, a corresponding waveform concentric to the rotation axis x results on its surface. This waveform ensures that the central milling cutter 11 and the ring milling cutters 12 engage optimally in the pile head 80 and dissolve 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 the surface tension in the pile core 81 and the surface tension in the pile jacket 82 to be advantageously released while avoiding damage to the pile head 80.

(22) After finishing the machining of the pile head 80, the milling head 1 is lifted again. The remaining concrete sleeve 88, which still encloses and protects the iron armouring 83, is then removed with little effort using other tools such as milling and clamping.

(23) FIG. 2 shows the milling head 1 from below with a view of the inner ring plate 112 equipped with the central chisels 111 and the outer ring plate 122 equipped with the ring chisels 121, which cover a central circular ring area kr1 corresponding to the pile core 81 and an outer circular ring area kr3 corresponding to the pile jacket 82 in accordance with the geometry of the machined pile 8 and delimit a middle circular ring area kr2, into which a concrete sleeve 88 with the iron armouring 83 remaining after the machining of the pile head 80 can enter. Part of the middle circular ring area kr2 is shown hatched.

(24) The outer ring plate 122 has an outer diameter d1220 and an inner diameter d1221. The inner ring plate 112 has an outer diameter d112.

(25) On the outer ring plate 122, three series 121A, 121B, 1210 of twelve spirally arranged ring chisels 121 or 1211, 1212, . . . , 12112 are each arranged offset by 120. Three ring chisels 121 each follow the same work circle m1 (only one work circle m1 shown). The mounting height of the ring chisels 121 increases from the first ring chisel 1211 to the last ring chisel 12112 or from one work circle m1 to the next work circle m1 radially from the inside to the outside, preferably continuously, which is why the outermost ring chisels 12112 lie highest in the milling direction and therefore first grip the outer edge of the pile jacket 82. In this way, the pile jacket 82 is machined from the outside inwards, which is why harmful splitting is avoided. The increase in mounting height of the ring chisels 121 is preferably in a range of 5 mm-25 mm. For example, the increase in mounting height of the first ring chisels 1211, 1212, . . . is close to 5 mm and the increase in mounting height of the last ring chisels . . . , 12111, 12112 is close to 25 mm.

(26) On the inner ring plate 112, which is shown larger in FIG. 3a, two series 111A, 111B of eight spirally arranged central chisels 111 and 1111, 1112, . . . , 1118 are each arranged offset by 180.

(27) As FIG. 3b shows, two diametrically opposed central chisels 111 follow the same work circle m1. The mounting height of the central chisels 111 increases from the first central chisel 1111 to the last central chisel 1108 radially from the outside to the inside, preferably continuously, which is why the central chisels 1108 lying closest to the rotation axis x lie highest in the milling direction and therefore penetrate first into the centre 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, which allows the pile core 81 to be machined more quickly.

(28) 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.

(29) The central chisels 111 are radially offset from each other in pairs at equal or unequal chisel distances ma and define a work circle m1 during rotation. The difference in the radii of the work circles m1 corresponds to the respective chisel spacing. The uniform chisel spacing ma or the different chisel distances ma are preferably in a range of 20 mm-40 mm. With this arrangement of the central chisels 111 the material is optimally removed. The work circles m1 are thus radially and also vertically offset from each other.

(30) The inner ring plate 112 also comprises two transfer openings 1120A, 1120B diametrically opposite each other with respect to the rotation axis x, through which the loosened milling material can be guided away. For the removal of the milled material, a conveyor shovel 119A, 119B is provided adjacent to the trailing edge of each of the transfer openings 1120A, 1120B, which on the one hand extend partially into the area of the respective transfer opening 1120A, 1120B and on the other hand partially into the working area of the central chisels 111. At the front, the conveyor shovels 119A, 119B comprise a front edge 1193, which extends from an inner edge to an outer edge of the conveyor shovels 119A, 119B. The front edge 1193 of the conveyor shovels 119A, 119B therefore first engages with the exposed milled material in order to guide it away upwards via the conveyor shovels 119A, 119B.

(31) FIG. 3a shows that the front edge 1193 is horizontally inclined relative to the diameter d112 of the inner ring plate 112 by a horizontal inclination angle a1 in such a way that, when the milling head 1 rotates in the working direction, the outer edge 1192 of the respective conveyor shovel 119A; 119B precedes and the inner edge 1191 follows behind. The milling material is therefore first caught on the outside of the front edge 1193 and displaced inwards against the corresponding transfer opening 1120A, 1120B. The displacement of the milled material results in a favourable material flow that relieves the load on the conveyor shovels 119A, 119B. The horizontal inclination angle or advance angle a1 is preferably in a range of 0-25.

(32) Each of the transfer openings 1120A, 1120B is also associated with a radial shovel 118A, 118B which conveys the milled material exposed by the central drill unit 114 and the inner central chisels 111 outwardly to the transfer openings 1120A, 1120B. The radial shovels 118A, 118B can be simple plates which are preferably form-fittingly held by the inner ring plate 112 and are preferably radially or inclined towards the associated transfer opening 1120A, 1120B.

(33) FIG. 3b further shows that a clearing chisel 1119A, 1119B is mounted on the leading edge of each of the transfer openings 1120A, 1120B, which projects outwards beyond the inner ring plate 112 by a clearance width b, which is preferably in a range of 5 mm-40 mm. The clearing chisels 1119A, 1119B pick up concrete particles that have not yet been loosened and could damage the conveyor shovels 119A, 119B, as well as the milling material lying on the outside, and convey it 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 chisels 121, which are preferably larger than the central chisels 111.

(34) To ensure that the milled material can be grasped well peripherally, the conveyor shovels 119A, 119B can also project radially outwards beyond the inner ring plate 112 by up to 35 mm.

(35) FIG. 3b further shows that the inner ring plate 112 has mounting holes 1128 on the lower side, into which the central chisels 111 or holders for the central chisels 111 are inserted.

(36) FIG. 4 shows a part of the central milling cutter 11 with the inner ring plate 112, the central drill unit 114, only three mounted central chisels 1112A, 1115B, 1118A and one of the transfer openings 1120B, to which the associated radial shovel 118B and the associated conveyor shovel 119B, which extend into the working area of the central chisels 111, adjoin. For each of these tools the penetration depth is shown; for the central drill unit 114 the penetration depth to, for the central chisels 1112A, 1115B, 1118A the penetration depths t1, t2, t3, for the inner edge 1181 and the outer edge 1182 of the radial shovel 118B the penetration depths t1181, t1182 and for the inner edge 1191 and the outer edge 1192 of the conveyor shovel 119B the penetration depths t1191, 1192.

(37) The front edge 1183 of the radial shovel 118B extends from the inner edge 1181 to the outer edge 1182 or from the penetration depth t1181 to the penetration depth t1182 with a descending outward slope. The front edge 1193 of the conveyor shovel 119B extends from the inner edge 1191 to the outer edge 1192 or from the penetration depth t1191 to the penetration depth t1182 with a descending outward slope.

(38) The front edge 1193 of the conveyor shovel 119B is vertically inclined relative to the diameter d112 of the inner ring plate 112, preferably by a vertical inclination angle a2, in such a way that the inner edge 1191 is preferably higher than the outer edge 1192 in the conveying direction in accordance with the course of the mounting heights of the central chisels 111. The conveyor shovel 119B can therefore not come into contact with the surface of the pile head 80 or the pile core 81.

(39) Preferably, a shovel spacing a3 is provided between the front edge 1193 of the conveyor shovel 119 and the working circles m1 of the central chisels 111 or the tips of the central chisels 111, which lies in a range of preferably 5 mm-40 mm.

(40) FIG. 4 further shows that the central drill unit 114, which comprises a milling tool or drilling tool 1141 and a tool shaft 1142, is held in a mounting part or drill chuck 1143 and fixed by means of a locking part 11431, for example by a bolt.

(41) FIG. 5a shows a spatial representation of the inner ring plate 112 of FIG. 3a, fully equipped with 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 is marked with the corresponding order numbers 1111, 1112, . . . , 1108. Furthermore, a view over the conveyor shovel 119B through the transfer opening 1120B is shown on the right.

(42) FIG. 5b shows the inner ring plate 112 of FIG. 5a after removal of the central chisels 111 and the conveyor shovel 119B as well as the removal of the central drill unit 114 together with the drill chuck 1143 from a recess 1129 of the inner ring plate 112. Furthermore, recesses 1123 are visible on the lower side of the inner ring plate 112, which serve to accommodate the radial shovels 118A, 118B. The housing 121F of the clearing chisel 1119B is still mounted.

(43) For the realisation of the assembly heights or the mutual vertical displacement of the central chisels 111, the lower side of the inner ring plate 112 is provided with ring-shaped steps S1, S2, S3, S4, S5, which preferably correspond to the working circles m1.

(44) FIG. 6a shows the inner ring plate 112 of FIG. 5a from above with the conveyor spirals 113A, 113B adjoining the upper: side of the inner ring plate 112 and rotated 180 relative to each other, which surround the shaft 115 of the central milling cutter 11 and which are each provided with a spiral wall 1130 in this section. The transfer opening 1120B is shown, to which the conveying bucket 119B, projecting into the working area of the central chisel 111, adjoins on the underside and to which the conveying spiral 113B adjoins on the upper side. The inner ring plate 112 has a transfer surface 1125A, 1125B for each of the transfer openings 1120A, 1120B, via which the milling material is conveyed from the conveyor shovel 119A, 119B to the associated conveyor spiral 113A, 113B. It is possible to cover this transfer surface 1125A, 1125B completely by the conveyor shovel 119A, 119B. The conveyor shovel 119A, 119B can therefore be welded to the lower end of the transfer surface 1125A, 1125B at the front, for example, or it can be attached to the associated transfer surface 1125A, 1125B, or it can be screwed on.

(45) The conveyor shovel 119B, which adjoins the lower side of the transfer opening 1120B or extends further, is inclined by an inclination angle of the shovel a4 with respect to the rotation axis x and forms an inclined plane. The inclination angle of the shovel a4, with which the conveyor shovel 119B is inclined with the front edge 1193 forwardly below the transfer opening 1120B, is in a range of preferably 5-85. Preferably, a vertical orientation of the conveyor shovel 119B is avoided, where the milling material is pushed forward and hardly displaced upwards. The inclination angle of the shovel a4, which in the embodiment shown is about 45, is therefore selected in such a way that the milled material can pass over the conveyor shovel 119B to the transfer opening 1120B and on to the conveyor spiral 113B. To prevent the conveyed milling material from escaping to the outside, the conveyor shovel 119B comprises an outer wall 1195.

(46) The transfer surface 1125B is preferably shaped in such a way that a preferably laminar transition without obstacles results between conveyor shovel 119B at the entrance of conveyor spiral 113B.

(47) FIG. 6b shows the inner ring plate 112 of FIG. 6a without the conveyor spirals 113A, 113B, the shaft 115 and the conveyor shovel 119B. After removing the conveyor shovel 119B, a connecting space with a connecting surface 1127 is exposed on the lower edge of the transfer surface 1125B or on the lower side of the transfer opening 1120B, in which the conveyor shovel 119B can be fastened, for example screwed and/or welded. Also exposed are the connecting surfaces 1126A, 1126B for the conveyor spirals 113A, 113B, which extend to an edge or a stop 11261, which is flush with the upper edge of the associated conveyor spiral 113A, 113B, so that the milling material can enter the conveyor spiral 113A, 113B unhindered.

(48) FIG. 7a shows a central chisel 111 comprising a holder 111F and a chisel element 111M inserted therein.

(49) FIG. 7b shows a ring chisel 121 comprising a holder 121F and a chisel element 121M inserted therein. In the present embodiment, the ring chisel 121 is also used as a clearing chisel, as shown in FIG. 6b.

LIST OF REFERENCES

(50) 1 milling head 11 central milling cutter 111, 1111, . . . , 1118 central chisels 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 openings 1123 mounting holes for the radial shovels 1124 receiving aperture for the shaft 115 1125A, 1125B transfer surfaces of the transfer openings 1126A, 1126B connecting surface for the conveyor spirals 1127 connecting surfaces for the conveyor shovels 1128 mounting holes for central chisels 111 1129 receiving aperture for the mounting part 1143 113A, 113B conveyor spirals 1130 spiral wall 114 central drill unit 1141 milling tool, hard metal cutting edges 1142 tool shaft 1143 mounting part, drill chuck 11431 locking part 115 shaft 118A, 118B radial shovels 1181 inner edge of the radial shovels 1182 outer edge of the radial shovels 1183 front edge of the radial shovels 119A, 119B conveyor shovel 1191 inner edge of the conveyor shovels 1192 outer edge of the conveyor shovels 1193 front edge of the conveyor shovels 1195 outer wall of the conveyor shovels 12 ring milling cutter 121; 1211, . . . , 12112 ring chisels 121A, . . . , 131C ring chisel groups 121F chisel holder 121M chisel or tool 122 outer ring plate 123 mounting cylinder 1231 exit window 1232 mounting window for access 13 coupling device 131 coupling sleeve 132 coupling means, coupling bolt 133 coupling plate 134 counter plate 14 connecting device 2 drive shaft 8 pile 81 pile core 82 pile jacket 83 metal armouring 88 concrete sleeve a1 horizontal inclination angle of the front edge a2 vertical inclination angle of the front edge a3 shovel spacing a4 inclination angle of the shovel b clearance width d pile diameter d112 outer diameter of the inner ring plate d122i inner diameter of the outer ring plate d122o outer diameter of the outer ring plate d1 milling line along the pile diameter h1 pile height h2 pile head height kr1, central circular ring area kr2 middle circular ring area kr3 outer circular ring area ma chisel spacing m1 chisel lines, work circles S1, . . . , S5 steps at the inner ring plate 112 t0 penetration depth of the central drill units t1 penetration depth of the central chisel 1118A t2 penetration depth of the central chisel 1115B t3 penetration depth of the 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 (FIG. 1b)