3D building material printer

Abstract

The invention relates to a method and a 3D building material printer (1), in particular a 3D concrete printer, for the 3D printing of building material strands (2), in particular concrete strands, comprising: a building material outlet nozzle (3) with a building material outlet opening (4) for letting out building material; a longitudinal reinforcement element discharge device (6) with a longitudinal reinforcement element discharge opening (18) for discharging a longitudinal reinforcement element (12); and a longitudinal reinforcement element guide (11) for guiding the longitudinal reinforcement element (12) to the longitudinal reinforcement element discharge opening; an advancing apparatus for advancing the building material outlet nozzle (3) and the longitudinal reinforcement element discharge device (6) in a longitudinal direction (10) such that a building material strand (2), which extends in the longitudinal direction (10), can be printed from the building material coming out of the building outlet nozzle (3), wherein the longitudinal reinforcement element guide () extends into the interior of the building material outlet nozzle (3) such that the longitudinal reinforcement element (12) can be discharged into the outlet cross-section of the building material at the building material outlet opening (4), wherein the longitudinal reinforcement element discharge device (6) is configured to embed the longitudinal reinforcement element (12) in the interior of the building material strand (2) in the longitudinal direction (10) of the building material strand (2), wherein a lifting and / or lowering apparatus (13) is provided by means of which the longitudinal reinforcement element (12) discharged into the outlet cross-section of the building material at the building material outlet opening (18) and embedded in the building material strand (2) is guided out of the building material strand (2) at lifting and / or lowering points (14) transverse to the longitudinal direction (10) such that the building material strand (2) can be connected, at the lifting and / or lowering points (14), to a building material strand (2) lying thereabove or therebelow.

Description

[0001] 3D building material printer

[0002] The invention relates to a 3D building material printer, in particular a 3D concrete printer, for 3D printing building material strands, in particular concrete strands, comprising: a building material outlet nozzle with a building material outlet opening for the discharge of building material, a longitudinal reinforcement element dispensing device with a longitudinal reinforcement element dispensing opening for dispensing a longitudinal reinforcement element and with a longitudinal reinforcement element guide for guiding the longitudinal reinforcement element to the longitudinal reinforcement element dispensing opening, a feed device for advancing the building material outlet nozzle and the longitudinal reinforcement element dispensing device in a longitudinal direction, so that a building material strand extending in the longitudinal direction can be printed from the building material emerging from the building material outlet nozzle.

[0003] Furthermore, the invention relates to a method for 3D printing building material strands, in particular concrete strands.

[0004] The ongoing development of additive manufacturing methods also offers new perspectives for the construction industry and the opportunity to achieve a higher degree of automation. Of particular relevance to the construction industry is 3D printing with concrete or other cement-based building materials, as this allows concrete elements to be manufactured in a largely automated manner. Another advantage of 3D concrete printing is the high degree of flexibility in shaping printed elements. While cast concrete elements require complex formwork that must correspond to the negative of the desired element, 3D concrete printing can also be used to produce complex geometries in a short time and with relatively little effort, or even without formwork. A further advantage of 3D concrete printing is, for example, a cost-effective reduction in the necessary component thicknesses and the associated savings in material, weight and CO2.As is the case with conventional filament-based 3D printers, the element to be printed can be formed in layers from individual strands, in the case of 3D concrete printers from concrete strands. Due to the mechanical properties of concrete, in particular due to the relatively low tensile strength compared to the high compressive strength, it is advantageous to provide longitudinal reinforcement in concrete elements to increase the longitudinal tensile strength. Due to the structure of 3D-printed concrete elements from individual concrete strands, it is also advantageous for the stability of printed concrete elements to connect individual parallel concrete strands transversely to one another using transverse reinforcement in order to increase and thus improve the tensile strength transverse to the concrete strands, the so-called transverse tensile strength. The longitudinal and transverse reinforcements are usually introduced separately into the concrete strands. However, this is very complex.

[0005] FR 3 123 585 discloses a concrete printer with which individual concrete strands can be printed and reinforced with a reinforcing fiber. The concrete printer has a print head with which the concrete is dispensed, and a feeding device with which the reinforcing fiber is dispensed. Connected to the feeding device is an injection device which can be moved up and down in order to sink the reinforcing fiber into the previously printed concrete strands below. This can improve the connection between the printed concrete strands. The feeding and injection device is arranged in front of the print head in the printing direction. The print head therefore lags behind the feeding and injection device. However, this design has the disadvantage that a comparatively elongated design is required, which limits the applications of the 3D printer.For example, care must be taken to ensure that the print head does not move into previously printed concrete strands, already installed reinforcement, and / or surrounding objects. Furthermore, known 3D printers are subject to limitations regarding the printable curvature radii in the plane.

[0006] This disadvantage also occurs in the other known versions of US 2020 / 149269 Al, US 2017 / 182712 Al or DE 10 2020 120895 Al, in which the reinforcements and the building material are also provided at a distance from each other.

[0007] CN 112 847 733 A also discloses a print head for a 3D mortar printer with a line and a nozzle for the mortar. The print head has a device for dispensing wire to improve the strength of an intermediate layer. The wire can, for example, penetrate an upper layer of mortar and the next layer using a compressed air device. The wire therefore only serves as transverse reinforcement. A spool for storing the wire, a feed device, a cutting device with pneumatic scissors, and a guide tube for the (cut) wire are provided. The guide tube has a funnel-shaped inlet to make it easier to pick up the wire. The print head can be moved using a mobile platform of a 3D printer to print layers of mortar. This prior art therefore only discloses the arrangement of transverse reinforcements using compressed air through several layers of mortar.

[0008] In contrast, the object of the present invention is to remedy or mitigate at least some of the disadvantages of the prior art. The invention specifically aims to provide a compact 3D building material printer with which building material elements of a wide variety of geometries with high longitudinal and transverse tensile strength can be produced.

[0009] This object is achieved by a 3D building material printer according to claim 1 and a method according to claim 9. Preferred embodiments are specified in the dependent claims.

[0010] According to the invention, the longitudinal reinforcement element guide extends into the interior of the building material outlet nozzle, so that the longitudinal reinforcement element can be delivered into the exit cross-section of the building material at the building material outlet opening. The longitudinal reinforcement element delivery device is designed to embed the longitudinal reinforcement element inside the building material strand, in the longitudinal direction of the building material strand. Furthermore, a lifting and / or lowering device is provided with which the longitudinal reinforcement element delivered into the exit cross-section of the building material at the building material exit opening and embedded in the building material strand is led out of the building material strand at lifting and / or lowering points transversely to the longitudinal direction, so that the building material strand can be connected to a building material strand located above or below it at the lifting and / or lowering points.

[0011] The 3D building material printer has a building material outlet nozzle with a building material outlet opening for the discharge of building material. The building material outlet opening can be round, for example, in particular circular. The diameter of the building material outlet opening can be between 5 mm (millimeters) and 100 mm, for example. The building material outlet nozzle can be advanced at least in one longitudinal direction by means of a feed device. If the building material outlet nozzle dispenses building material during the feed, a building material strand is printed along the longitudinal direction. The height of a building material strand can be between 4 mm and 50 mm, for example. The width of a building material strand can essentially correspond to the diameter of the building material outlet nozzle. The width of a building material strand can, for example, correspond to up to four times the diameter of the building material outlet nozzle.Both straight and curved building material strands can be printed by moving the building material outlet nozzle accordingly. The building material outlet nozzle is preferably arranged substantially perpendicular to the longitudinal direction, i.e., to the strand direction of the building material strands. The feed device can have a drive with which the building material outlet nozzle can be displaced at least along one axis. Preferably, the drive is configured for displacement in three axes, in particular in the three orthogonal spatial axes. The feed occurs at a feed rate that can be constant or can vary depending on the location. The feed rate can, for example, be between 10 cm / s (centimeters per second) and 50 cm / s.

[0012] The preferred building material is a cement-based building material, in particular concrete or mortar, or gypsum or geopolymer concrete or a cement-free concrete.

[0013] The building material outlet nozzle and the longitudinal reinforcement element dispensing device together form a print head. Since the longitudinal reinforcement element is dispensed into the outlet cross-section of the building material outlet nozzle, it is possible to achieve virtually any curvature radii in a horizontal plane, as the print head can be designed to be particularly short in the longitudinal or feed direction. In contrast, in the prior art, the building material outlet nozzle and the longitudinal reinforcement element dispensing opening were spaced apart from one another in the longitudinal direction of the building material strands, which severely restricted the printable geometries. Furthermore, a rear part of the print head, viewed in the printing direction, would pivot out when the feed direction changed, which in turn would restrict the printing process and / or the dispensing of the longitudinal reinforcement element.In order to achieve the desired compact design and to prevent excessive swinging out of the print head, it is therefore crucial that the longitudinal reinforcement element guide extends into the interior of the building material outlet nozzle so that the longitudinal reinforcement element and the building material are discharged at essentially the same location.

[0014] With the help of the lifting and / or lowering device, the longitudinal reinforcement element, which is released into the exit cross-section of the building material at the building material outlet opening and embedded in the building material strand, can be led out of the just-printed building material strand in the area of ​​the lifting and / or lowering points, transversely to the longitudinal direction. This allows the just-printed building material strand to be connected by the lifting and / or lowering points of the longitudinal reinforcement element to a previously printed, underlying building material strand or to a later printed, overlying building material strand. Advantageously, the longitudinal reinforcement element at the lifting and / or lowering points also forms the transverse reinforcement, with which several building material webs can be connected to one another.The longitudinal reinforcement element therefore has longitudinal sections located within the currently printed building material strand to form the longitudinal reinforcement and lifting and / or lowering points located outside the currently printed building material strand to form the transverse reinforcement. The longitudinal and transverse reinforcement are therefore formed in one piece by the longitudinal reinforcement element, which is preferably an endless element, in particular an endless thread. In contrast to the prior art, the lifting and lowering device is designed to displace the longitudinal reinforcement element delivered into the outlet cross section of the building material at the building material outlet opening in the vertical direction in such a way that the lifting and lowering points are formed. In this way, transverse reinforcement can be formed in one piece with the longitudinal reinforcement without having to give up the compact design of the print head.A particular advantage is that the lifting and lowering device can be guided essentially along the same path as the concrete outlet nozzle. In contrast to the prior art, the lifting or lowering device according to the invention is combined with the outlet nozzle and its outlet opening. This results in the advantage that the building material outlet opening always coincides with the reinforcement device. Neither translations nor rotations change the geometric placement in space. Special cases due to nozzle positions do not require any additional solutions or programming.

[0015] The lifting and lowering device preferably has an electric, pneumatic, mechanical or hydraulic drive to achieve the lifting or lowering of the longitudinal reinforcement element.

[0016] With the help of the feed device, the building material outlet nozzle can be guided along a predefined path together with the longitudinal reinforcement element dispensing device. The building material outlet nozzle can be movable along one or more, in particular three mutually orthogonal, axes by means of the feed device. After a building material strand has been printed, the building material outlet nozzle can, for example, be raised vertically together with the longitudinal reinforcement element dispensing device by means of the feed device and moved over the previously printed building material strand in order to print two superimposed building material strands.

[0017] At the lifting or lowering point, at least two and preferably fewer than eight material strands are connected transversely to each other. The material strands can also be referred to as printed webs. The tensile strength of 3D-printed material elements can be significantly increased and thus improved by the longitudinal reinforcement element.

[0018] The 3D building material printer can be operated at a fixed location, for example, in a hall, to serially produce building material elements at that location. The building material elements can be transported to a construction site after their production, especially after they have cured. Alternatively, the 3D building material printer can be mobile and operated on a construction site to produce building material elements directly at or near the destination.

[0019] For the purposes of this disclosure, all directions and positions, such as "vertical," "horizontal," "top," and "bottom," are specified with respect to the intended use of the 3D building material printer. For example, liquid building material is dispensed along a horizontally extending material strand. Gravitational acceleration points vertically downward from top to bottom. If printing occurs along an inclined plane, printed building material strands may also have a corresponding vertical extension. In this case, the location and direction information must be transferred accordingly.

[0020] Preferably, the longitudinal reinforcement element guide extends within the building material outlet nozzle substantially perpendicular to the building material outlet opening. This allows the longitudinal reinforcement element to be discharged substantially in the flow direction of the building material in the building material outlet nozzle. The longitudinal reinforcement element guide can, for example, comprise a hollow element, in particular a straight guide tube.

[0021] Preferably, a building material supply device is provided, which is configured to supply liquid building material to the building material outlet nozzle. The building material supply device can, for example, comprise a building material mixer, in particular a mobile building material mixer, preferably a truck mixer, which is connected to the building material outlet nozzle via a supply line. The building material supply device can comprise a pump or a screw conveyor, by means of which liquid building material can be transported to the building material outlet nozzle. The building material supply device can be configured to be able to control the supply of building material, in particular the volume and / or mass of liquid building material per unit of time, to the building material outlet nozzle.The building material outlet nozzle preferably has a building material line with at least one initial section connected to the building material supply device, a curved intermediate section and an end section having the building material outlet opening, wherein the longitudinal reinforcement element guide enters the building material line, in particular into the curved intermediate section. The longitudinal reinforcement element guide preferably penetrates a wall of the building material line so that the longitudinal reinforcement element can be guided through the wall into the interior of the building material line by means of the longitudinal reinforcement element guide. In particular, if the longitudinal reinforcement element guide is straight, it is advantageous if the longitudinal reinforcement element guide enters the curved intermediate section.This arrangement makes it possible to design the pressure head comprising the building material outlet nozzle and the longitudinal reinforcement element dispensing device with the longitudinal reinforcement element guide particularly compactly and to dispense the longitudinal reinforcement element essentially in the flow direction of the building material at the building material outlet opening. The initial section and the end section are preferably straight. The longitudinal reinforcement element guide can be arranged coaxially to the end section of the building material outlet nozzle. In a preferred embodiment, the building material line has two curved line sections between the initial and the end section, wherein the initial section forks into the two curved line sections, which are brought together in the end section.

[0022] To form the feed device, in a preferred embodiment, the 3D building material printer can have a robot arm with at least three robot axes, with the building material outlet nozzle being an end effector of the robot arm. The robot arm can preferably have three translational and three rotational robot axes, with which the building material outlet nozzle can be moved. Using a robot arm allows for the printing of particularly complex geometries.

[0023] In a first preferred embodiment, the lifting and / or lowering device has a delivery element which projects from the building material outlet opening and is movable upwards and downwards by means of a lifting and / or lowering drive, preferably substantially in the vertical direction, and which has the longitudinal reinforcement element delivery opening for delivering the longitudinal reinforcement element. By actuating the lifting and / or lowering drive, the delivery element is moved upwards or downwards, as a result of which the longitudinal reinforcement element emerges further up or further down from the delivery opening. This forms the lifting or lowering point at which the longitudinal reinforcement element is led out of the cross-section of the building material strand to form the transverse reinforcement. The delivery opening for the longitudinal reinforcement is preferably provided adjacent to the building material outlet opening.

[0024] The lifting or lowering drive can be operated in a recurring rhythm or without regularity.

[0025] The discharge element is preferably a discharge pipe passing through the building material outlet opening, with the longitudinal reinforcement element discharge opening being formed at the lower end of the discharge pipe. By moving the discharge pipe upwards or downwards, the discharge position for the longitudinal reinforcement element can be changed.

[0026] In order to guide the longitudinal reinforcement element through the interior of the building material outlet nozzle and to be able to change the delivery position to form the lifting or lowering points, the delivery pipe is preferably arranged concentrically to a guide pipe of the longitudinal reinforcement element guide extending within the building material outlet nozzle.

[0027] In a second preferred embodiment, the lifting and lowering device has a rotor element with at least one hook and a rotor drive for rotating the rotor element with the at least one hook, wherein the rotor element is designed to deflect the longitudinal reinforcement element from the longitudinal direction with the hook at the lifting and / or lowering points. The rotor drive is designed to guide the hook past the building material outlet nozzle adjacent to the building material outlet opening so that the longitudinal reinforcement element is gripped to form the lifting or lowering point. In this embodiment, the longitudinal reinforcement element discharge opening can be formed at the lower end of a guide tube of the longitudinal reinforcement element guide.

[0028] In a third preferred embodiment, the lifting and / or lowering device has a lifting and / or lowering element arranged outside the outlet nozzle, preferably surrounding the outlet nozzle, for lifting and / or lowering the longitudinal reinforcement element at the lifting and / or lowering points.

[0029] In this embodiment, the lifting element preferably has a support surface for the longitudinal reinforcement element, wherein the lifting element is movable between a first, preferably lower, position in which the longitudinal reinforcement element is guided within the building material strand over the support surface, and a second, preferably upper, position in which the longitudinal reinforcement element is guided outside the building material strand over the support surface. In the first position of the lifting element, the longitudinal reinforcement element is arranged within the building material strand. In the second position of the lifting element, the lifting point is formed.

[0030] For stability reasons, it is advantageous if the longitudinal reinforcement element delivery device for delivering the longitudinal reinforcement element is designed essentially centrally in the building material strand, so that the longitudinal reinforcement element outside the lifting and / or lowering points is essentially completely and preferably essentially uniformly surrounded on the circumference by the building material of the building material strand.

[0031] In the method according to the invention for 3D printing building material strands, in particular concrete strands, at least the following steps are carried out:

[0032] Feeding liquid building material into a building material outlet nozzle of a 3D building material printer, which is preferably designed according to one of the embodiments described above, advancing the building material outlet nozzle, wherein liquid building material is dispensed from a building material outlet opening of the building material outlet nozzle, so that a building material strand is formed from the liquid building material;

[0033] Inserting a longitudinal reinforcement element into the interior of the building material outlet nozzle; discharging the longitudinal reinforcement element into the outlet cross-section of the liquid building material at the building material outlet opening;

[0034] Embedding the longitudinal reinforcement element in the building material along the building material strand,

[0035] Leading out the longitudinal reinforcement element at lifting and / or lowering points from the building material strand;

[0036] Connecting the building material strand at the lifting and / or lowering points transversely to the building material strand with a building material strand above it or with a building material strand below it.

[0037] The integrated longitudinal reinforcement is preferably released as a continuous fiber via the outlet nozzle and is preferably positioned essentially centrally in the concrete strand so that the longitudinal reinforcement is enveloped in its longitudinal sections by the material that has not yet hardened. The building material hardens quickly so that the next building material strand layered on top can bond with the previous building material strand. This time depends on the size of the building element being manufactured and, when concrete is used, also on the aggregates matched to it. The previous layer should not be crushed by the layer above it, but at the same time still have enough moisture for good adhesion so that the element is as monolithic as possible. In order for the material adhesion and the bonding to be successful, the material must be bonded together accordingly.The 3D printing process is being further developed because the chemical bond between the concrete layers is no longer solely responsible for the stability of the concrete element. By locally raising, lowering, and connecting the reinforcement strands via the longitudinal reinforcement element, the connection between the compression layers is strengthened. The longitudinal reinforcement is guided through the material outlet nozzle, ensuring the embedding of the longitudinal reinforcement element in the material strand.

[0038] In a preferred embodiment, the longitudinal reinforcement element is lifted out of the material strand at lifting points, with the overlying material strand passing through the lifting and / or lowering points of the longitudinal reinforcement element. Thus, the material strand is pressed first, the longitudinal reinforcement element is lifted out of the material strand at the lifting points, and then the overlying material strand is pressed through the lifting points.

[0039] In a further preferred embodiment, the longitudinal reinforcement element is pressed at countersunk points into an underlying strand of building material which is at least not yet completely hardened.

[0040] In order to increase the stability of the building material strand, the longitudinal reinforcement element is preferably embedded substantially centrally in the building material strand, wherein the longitudinal reinforcement element is completely and preferably substantially uniformly surrounded on the circumference by the building material of the building material strand outside the lifting and / or lowering points.

[0041] As a longitudinal reinforcement element, a reinforcement thread, in particular an endless thread, is preferably used, which is preferably carried from the building material strand into the building material strand above it.

[0042] The reinforcement thread is preferably a textile reinforcement, in particular comprising at least one of aramid, glass, carbon, or basalt fibers. Depending on the design, the textile reinforcement can be formed from at least one aramid, glass, carbon, or basalt fiber, or the textile reinforcement can comprise a matrix material, in particular resin, in addition to this fiber, so that the textile reinforcement is formed as a composite material.

[0043] In a preferred embodiment, the reinforcement thread has a surface structure so that the building material at the building material outlet opening takes the reinforcement thread with it and embeds it in the building material strand.

[0044] The invention is explained in more detail below with reference to embodiments shown in the drawings.

[0045] Fig. 1 to Fig. 3 show a first embodiment of a 3D concrete printer according to the invention, with which a longitudinal reinforcement element is dispensed via a concrete outlet nozzle, embedded in the concrete strand emerging from the concrete outlet nozzle and pressed at depressions into the underlying, not yet fully cured concrete strand.

[0046] Fig. 4 and Fig. 5 show a second embodiment of the 3D concrete printer according to the invention, wherein the longitudinal reinforcement element is lifted out of the concrete strand at lifting points by hooks of a rotating rotor element, so that the concrete strand printed above it in the next step passes through the lifting points.

[0047] Fig. 6 to Fig. 8 show a third embodiment of the 3D concrete printer according to the invention, wherein the longitudinal reinforcement element is guided under the concrete outlet nozzle via a lifting element with which the longitudinal reinforcement element is lifted at lifting points.

[0048] Fig. 1 and Fig. 2 show a 3D building material printer 1, here a 3D concrete printer, during the 3D printing of building material strands 2, here concrete strands. The 3D building material printer 1 has a building material outlet nozzle 3, here a concrete outlet nozzle, with a building material outlet opening 4 for the outlet of building material 5, from which a plurality of building material strands 2 are formed one above the other. In addition, the 3D building material printer has a longitudinal reinforcement element dispensing device 6. The building material outlet nozzle 3 and the longitudinal reinforcement element dispensing device 6 together form a print head. The building material outlet nozzle 3 has a building material line with an initial section 7, which is connected to a building material supply device (not shown) for supplying building material 5. The building material 5 is fed into the building material outlet nozzle 3 of the 3D building material printer 1 in a liquid, i.e., not completely cured, state.In the exemplary embodiment shown, the building material line has two bent line sections 8 between the initial section 7 and an end section 9 which opens into the building material outlet opening 4. The initial section 7 branches into the two bent line sections 8, which are brought together again in the end section 9. The flow of liquid building material 5 is divided by means of the two bent line sections 8, since building material 5 can flow parallel in both bent line sections 8. In the end section 9, the liquid building material 5 from the two bent line sections 8 is brought together again, so that any shading of an area of ​​the building material outlet opening 4 due to the viscosity of the building material 5 can be prevented.

[0049] To print building material strands 2, the building material outlet nozzle 3 can be moved in a longitudinal direction 10, during which time building material 5 is dispensed to obtain a building material strand 2 extending in this longitudinal direction 10. A feed device is provided for moving the building material outlet nozzle 3, which can be formed, for example, by a robot arm (not shown).

[0050] The feed device moves the building material outlet nozzle 3 together with the longitudinal reinforcement element dispensing device 6 in the longitudinal direction 10. By means of the building material 5 exiting the building material outlet nozzle 3, building material strands 2 extending in the longitudinal direction 10 can be printed one above the other. Once a building material strand 2 has been printed, the building material outlet nozzle 3 can be raised vertically and moved over one or more previously printed lower building material strands 16. This allows an upper building material strand to be printed directly onto a lower building material strand. Using the individual building material strands 2, a building material element can be printed, which can be, for example, a piece of building material furniture, a prefabricated building material component, or another structural building material part.

[0051] As further shown in Fig. 1 and Fig. 2, the longitudinal reinforcement element dispensing device 6 has a longitudinal reinforcement element guide 11. The longitudinal reinforcement element guide 11 enters the intermediate section with the curved line sections 8 of the building material line, so that a longitudinal reinforcement element 12 can be dispensed into the exit cross-section of the building material 5 at the building material exit opening 4. The longitudinal reinforcement element 12 is embedded in the interior of the building material strand 2 in the longitudinal direction 10 of the building material strand 2.

[0052] As can also be seen from Fig. 1 to Fig. 3, the 3D building material printer 1 also has a lifting and / or lowering device 13, with which the longitudinal reinforcement element 12 embedded in the building material strand 2 is led out of the building material strand 2 at lifting and / or lowering points 14 transverse to the longitudinal direction 10. As a result, the currently printed building material strand 2 can be connected at the lifting and / or lowering points 14 to a building material strand above it or to a building material strand 2 below it. The lifting and / or lowering device 13 has a (only symbolically shown) longitudinal reinforcement element control unit 15, which is connected to the print head via connections 16. Preferably, the connections 16 are movable so that the longitudinal reinforcement element control unit 15 can be adjusted relative to the pressure head, preferably in the vertical direction (cf. double arrow 15A in Fig. 1) and / or with regard to its rotational position (cf.Arrows 15B in Fig . 3 ) .

[0053] In the embodiment of Figs. 1 to 3, the lifting and / or lowering device 13 has a delivery element 17 protruding from the building material outlet opening 4 and having a longitudinal reinforcement element delivery opening 18 for delivering the longitudinal reinforcement element 12. The lifting and / or lowering device 13 has a lifting and / or lowering drive (symbolized in Fig. 1 by arrow 13A), with which the delivery element 17 is moved in the vertical direction.

[0054] In the embodiment shown in Fig. 1 to 3, the delivery element

[0055] 17, a discharge pipe is provided that extends downward through the building material outlet opening 4. The discharge opening 18 is formed at the lower end of the discharge pipe. The discharge pipe is arranged concentrically with a guide pipe 11A of the longitudinal reinforcement element guide 11, which extends within the building material outlet nozzle.

[0056] According to Fig. 1, the delivery element 17 is arranged in a first, upper position in which the longitudinal reinforcement element 12 is embedded centrally in the elongated building material strand 2.

[0057] According to Fig. 2, the delivery element 17 is arranged in a second, lower position, so that the longitudinal reinforcement element 12 is lowered from the delivery opening compared to the upper position.

[0058] 18 . This creates a countersink 14 at which the longitudinal reinforcement element 12 is pressed into the underlying building material strand 2 , which has not yet fully hardened.

[0059] Fig . 3 shows a section in Fig . 1 .

[0060] In the embodiment of Fig. 4 and 5, the lifting and lowering device 13 has a rotor element 19 with at least one hook 20, here three hooks 20. The rotor element 19 is connected to a (symbolically represented) rotor drive 21 so that the rotor element 19 can be rotated in both directions of rotation (see arrow 19A). As the rotor element 19 rotates, the hooks 20 periodically grip the longitudinal reinforcement element 12, lift it out of the central position within the building material strand 2 and release it again, whereby individual lifting points 14 are formed.

[0061] Fig. 4 shows the rotor element 19 in a first rotational state in which the hook 20 is just before contact with the longitudinal reinforcement element 12, which at this point in time is still embedded centrally in the cross-section of the building material.

[0062] Fig. 5 shows the rotor element 19 in a second rotational state in which the hook 20 has gripped the longitudinal reinforcement element 12 and pulled it upwards, so that a lifting point 14 has been formed.

[0063] In the embodiment of Fig. 6 to 8, the lifting and / or lowering device has a lifting and / or lowering element 22 arranged outside the building material outlet nozzle 3 for lifting and / or lowering the longitudinal reinforcement element 12 at the lifting and / or lowering points 14. In the example shown, the lifting element 22 has a plurality of ring-shaped support surfaces 23 for the longitudinal reinforcement element 12, over which the longitudinal reinforcement element 12 can be guided. The lifting element 22 can be raised and lowered, for example periodically, in order to form the lifting and lowering points 14.

[0064] Fig. 6 shows the lifting element 22 in a first, lower position, in which the longitudinal reinforcement element 12 is guided within the concrete strand over the support surface 23. Fig. 7 shows the lifting element 22 in a second, upper position, in which the longitudinal reinforcement element 12 is guided above the concrete strand 2 over the support surface 23, so that a lifting point 14 is formed.

[0065] Fig. 8 shows a section in Fig. 6. As illustrated by arrows 24, the lifting element 22 can be rotated with respect to its longitudinal axis, so that the longitudinal reinforcement element 12 can be threaded out of an opening of the lifting element 22 when the direction changes by rotating the lifting element 22.

[0066] The following process for 3D printing of building material strands, especially concrete strands, can be carried out with the 3D building material printer 1

[0067] Feeding liquid building material into a building material outlet nozzle of a 3D building material printer in one of the design variants described above,

[0068] Advancing the building material outlet nozzle, whereby liquid building material is discharged from a building material outlet opening of the building material outlet nozzle, so that a building material strand is formed from the liquid building material;

[0069] Guide a longitudinal reinforcement element into the interior of the building material outlet nozzle;

[0070] Dispensing the longitudinal reinforcement element into the outlet cross-section of the liquid building material at the building material outlet opening;

[0071] Embedding the longitudinal reinforcement element in the building material along the building material strand,

[0072] Leading out the longitudinal reinforcement element at lifting and / or lowering points from the building material strand;

[0073] Connecting the building material strand at the lifting and / or lowering points transversely to the building material strand with a building material strand above it or with a building material strand below it.

[0074] The preferred longitudinal reinforcement element is a reinforcement thread made of a rough-surface aramid, which is drawn directly along with the building material strand due to the woven surface structure. This causes the longitudinal reinforcement element to unwind and be drawn into the printed building material strand by the flow velocity of the building material itself.

[0075] Reference numbers:

[0076] 1 3D building material printer

[0077] 2 building material strands

[0078] 3 Building material outlet nozzle

[0079] 4 Building material outlet opening

[0080] 5 Building material

[0081] 6 Longitudinal reinforcement element delivery device

[0082] 7 Initial section

[0083] 8 curved cable sections

[0084] 9 Final section

[0085] 10 Longitudinal direction

[0086] 11 Longitudinal reinforcement element guide

[0087] 12 Longitudinal reinforcement element

[0088] 13 Lifting and / or lowering device

[0089] 13A Arrow

[0090] 14 lowering or lifting points

[0091] 15 Longitudinal reinforcement element control unit

[0092] 15A Arrow

[0093] 15B Arrow

[0094] 16 connections

[0095] 17 Dispensing element

[0096] 18 Longitudinal reinforcement element discharge opening

[0097] 19 Rotor element

[0098] 20 hooks

[0099] 21 Rotor drive

[0100] 22 Lifting element

[0101] 23 Support surface

[0102] 24 Arrow

Claims

Claims:

1. 3D building material printer (1), in particular 3D concrete printer, for 3D printing building material strands (2), in particular concrete strands, comprising: a building material outlet nozzle (3) with a building material outlet opening (4) for the discharge of building material, a longitudinal reinforcement element dispensing device (6) with a longitudinal reinforcement element dispensing opening (18) for dispensing a longitudinal reinforcement element (12) and with a longitudinal reinforcement element guide (11) for guiding the longitudinal reinforcement element (12) to the longitudinal reinforcement element dispensing opening, a feed device for advancing the building material outlet nozzle (3) and the longitudinal reinforcement element dispensing device (6) in a longitudinal direction (10), so that from the building material emerging from the building material outlet nozzle (3) a A building material strand (2) extending in the longitudinal direction (10) is printable, characterized in that the longitudinal reinforcement element guide (11) extends into the interior of the building material outlet nozzle (3),so that the longitudinal reinforcement element (12) can be delivered into the exit cross-section of the building material at the building material exit opening (4), wherein the longitudinal reinforcement element delivery device (6) is designed to embed the longitudinal reinforcement element (12) inside the building material strand (2) in the longitudinal direction (10) of the building material strand (2), wherein a lifting and / or lowering device (13) is provided, with which the longitudinal reinforcement element (12) delivered into the exit cross-section of the building material at the building material exit opening (18) and embedded in the building material strand (2) is led out of the building material strand (2) at lifting and / or lowering points (14) transversely to the longitudinal direction (10), so that the building material strand (2) at the lifting and / or lowering points (14) with a Building material strand (2) can be connected., 2. 3D building material printer (1) according to claim 1, characterized in that the lifting and / or lowering device (13) comprises a discharge element (17) projecting from the building material outlet opening (4) and movable up and down by a lifting and / or lowering drive with the longitudinal reinforcement element discharge opening (18) for discharging the longitudinal reinforcement element (12).

3. 3D building material printer (1) according to claim 2, characterized in that a discharge tube passing through the building material outlet opening (4) is provided as the discharge element (17), wherein the longitudinal reinforcement element discharge opening (18) is formed at the lower end of the discharge tube.

4. 3D building material printer (1) according to claim 3, characterized in that the discharge pipe is arranged concentrically to a guide pipe (11A) of the longitudinal reinforcement element guide (11) extending within the building material outlet nozzle (3).

5. 3D building material printer (1) according to claim 1, characterized in that the lifting and lowering device (13) comprises a rotor element (19) with at least one hook (20) and a rotor drive (21) for rotating the rotor element (19) with the at least one hook (20), wherein the rotor element (19) is designed to deflect the longitudinal reinforcement element (12) from the longitudinal direction (10) with the hook (20) at the lifting and / or lowering points (14).

6. 3D building material printer (1) according to claim 1, characterized in that the lifting and / or lowering device (13) has a lifting and / or lowering element (22) arranged outside the building material outlet nozzle (3), preferably surrounding the building material outlet nozzle (3), for lifting and / or lowering the longitudinal reinforcement element (12) at the lifting and / or lowering points (14).

7. 3D building material printer (1) according to claim 6, characterized in that the lifting element (22) has a support surface (23) for the longitudinal reinforcement element (12), wherein the lifting element (22) is movable between a first position in which the longitudinal reinforcement element (12) is guided within the building material strand (2) over the support surface (23), and a second position in which the longitudinal reinforcement element (12) is guided outside the building material strand over the support surface (23).

8. 3D building material printer according to one of claims 1 to 7, characterized in that the longitudinal reinforcement element dispensing device (6) for dispensing the longitudinal reinforcement element (12) is formed substantially centrally in the building material strand (2), so that the longitudinal reinforcement element (12) outside the lifting and / or lowering points (14) is completely enveloped on the circumference by the building material of the building material strand (2).

9. Method for 3D printing of building material strands (2), in particular concrete strands, comprising the steps: Feeding liquid building material into a building material outlet nozzle (3) of a 3D building material printer (1), in particular according to one of claims 1 to 8; Advancing the building material outlet nozzle (3), wherein liquid building material is discharged from a building material outlet opening (4) of the building material outlet nozzle (3), so that a building material strand (2) is formed from the liquid building material; guiding a longitudinal reinforcement element (12) into the interior of the building material outlet nozzle (3); Dispensing the longitudinal reinforcement element (12) into the outlet cross-section of the liquid building material at the building material outlet opening (4); Embedding the longitudinal reinforcement element (12) in the building material along the building material strand (2), characterized by Leading out the longitudinal reinforcement element (12) at lifting and / or lowering points (14) from the building material strand (2); Connecting the building material strand (2) at the lifting and / or lowering points (14) transversely to the building material strand (2) with an overlying building material strand (2) or with an underlying building material strand (2).

10. Method according to claim 9, characterized in that the longitudinal reinforcement element (12) is lifted out of the building material strand (2) at lifting points (14), wherein the building material strand (2) lying above passes through the lifting and / or lowering points (14) of the longitudinal reinforcement element (12).

11. Method according to claim 9 or 10, characterized in that the longitudinal reinforcement element (12) is provided at countersunk points (14) in an underlying, at least not yet fully cured building material strand (2) is pressed.

12. Method according to one of claims 9 to 11, characterized in that the longitudinal reinforcement element is embedded substantially centrally in the building material strand (2), wherein the longitudinal reinforcement element (12) is outside the lifting and / or lowering points (14) is substantially uniformly covered circumferentially by the building material of the building material strand (2).

13. Method according to one of claims 9 to 12, characterized in that a reinforcement thread, in particular an endless thread, is used as the longitudinal reinforcement element (12), which is preferably carried along from the building material strand (2) into the building material strand (2) lying above it.

14. Method according to claim 13, characterized in that the reinforcing thread comprises at least one of aramid, carbon, glass or basalt fiber.

15. Method according to claim 13 or 14, characterized in that the reinforcing thread has a surface structure so that the building material at the building material outlet opening (4) takes the reinforcing thread with it and embeds it in the building material strand (2).

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