major manipulator

Abstract

Large manipulator (2) with a mast arm (4) and a rotatable bearing of the mast arm (4), comprising: - a gear (22) which is arranged at the lower end of the mast arm (4) in a rotationally fixed manner, - a linear drive, (18) - a rack (20a, 20b) which is horizontally displaceable by means of the linear drive (18) and whose teeth engage with the gear (22), whereby the pushing movement of the rack (20a, 20b) is converted into a rotary movement of the mast arm (4), characterized in that the large manipulator has a further gear (24) which is arranged on the same axis as the first gear (22), wherein the further gear (24) transmits the rotary movement of the mast arm (4) to at least one rotation angle sensor (28) which detects the angle of rotation of the mast arm (4).

Description

[0001] The invention relates to the rotation angle detection of the mast arm of a large manipulator according to claim 1, claim 5, claim 6 and claim 10.

[0002] In both building construction and civil engineering, large manipulators, such as concrete pumps, are used to deliver concrete, usually delivered by mixer trucks, to the site for the construction of ceilings, walls, and the like. Both stationary concrete pumps and mobile concrete pumps, particularly so-called truck-mounted concrete pumps, are used for this purpose. In the case of truck-mounted concrete pumps, the pump is mounted on the frame or bed of a truck and draws concrete from a hopper located at the rear of the vehicle. The concrete is then distributed directly onto the construction site via an outgoing delivery line.Such truck-mounted concrete pumps typically have a boom arm constructed from several articulated boom segments that can be pivoted in a space-saving manner for operation. The individual boom arm segments are arranged more or less parallel, yet converged in a tight space, on the frame or platform, thus enabling easy road transport. Such boom arms are mounted via a tilting joint on a rotating column, which in turn is mounted on the vehicle frame, particularly on a boom stand firmly connected to the vehicle, so that it can rotate about a vertical axis.

[0003] Since strong tipping moments act on the vehicle when the boom is extended to a greater or lesser extent, and can also be pivoted as desired around the rotary column axis and can therefore also be adjusted to a position cantilevered to the side of the vehicle, these vehicles are equipped with laterally extendable support elements to ensure that the vehicles are supported safely and so stable against tipping. However, these supports are quite critical and, depending on the length of the boom arm, appropriately adapted support is required. Depending on the extended position of the boom arm relative to the vehicle and the center of gravity of the truck-mounted concrete pump, a certain extended position of the support elements is required. This is difficult on site, especially since there are often conditions on construction sites which severely restrict the position of the support elements. This means that, depending on the construction site or the location, the support elements must be positioned in a specific position.Depending on the vehicle's location, the outriggers can be fully extended on one side and not extended or only partially extended on the other. If the tipping moments occurring via the extended boom cannot be absorbed by the outriggers, the vehicle may tip over. It is obvious that on-site it cannot be left to the driver of the concrete vehicle to decide at which angle of rotation or extended position of the boom the vehicle may tip over in order to extend the outriggers accordingly. For this reason, these truck-mounted concrete pumps are often equipped with systems that record and evaluate the angle of rotation of the boom arm in order to take appropriate safety precautions, e.g. limiting the angle of rotation of the boom arm, to prevent the truck-mounted concrete pump from tipping over.

[0004] It is known from the prior art (EP 2 699 743 A1) to determine the angle of rotation of the mast arm using sensors on the drive motor for mast rotation. For this purpose, the revolutions of the drive motor, which drives the rotating column of the mast arm via a gear transmission, are counted, from which the angle of rotation of the mast arm can be determined.

[0005] US 5 557 526 A discloses a system for monitoring the operation of a boom arm in which loads or forces on the components of the boom arm are detected, information is stored based on the detected loads or forces, and an output is provided based on the stored information indicating possible causes and the expected time of boom arm failure.

[0006] DE 10 2011 018 267 A1 discloses a large manipulator in the form of a concrete pump, wherein for the purpose of angularly aligning a mast arm of the large manipulator, a turntable of the concrete pump is rotatable by a drive, in particular a hydraulic motor with a gear arranged thereon, preferably via a gear pinion acting on the slewing ring of the turntable, and with a measuring device equipped with angle of rotation sensors for measuring the angle of rotation of the turntable, wherein the measurement of the angle of rotation of the turntable is carried out by directly measuring the angle of rotation of the drive or of the gear arranged between the motor and the turntable.

[0007] In the case of truck-mounted concrete pumps in which the rotation of the boom arm is achieved by means of a linear drive, which consists, for example, of one or two horizontally arranged plunger cylinders which set the boom arm in a rotary movement via a cylinder rod designed as a rack, it is not yet possible to determine the angle of rotation of the boom arm.

[0008] For the above-mentioned reasons, the object of the present invention is to provide a rotation angle detection device for a large manipulator in which the mast arm is set in a rotary movement by means of a linear drive.

[0009] This problem is solved in a first variant by a large manipulator with a rotatably mounted mast arm according to claim 1. A gear, the so-called column pinion, is arranged in a rotationally fixed manner at the lower end of the mast arm. By means of a linear drive with a rack, which is horizontally displaceable by means of the linear drive and whose teeth engage with the gear, the pushing movement of the rack is converted into a rotary movement of the mast arm. The mast arm has another gear arranged on the same axis as the first gear. This additional gear transmits the rotary movement of the mast arm to at least one rotation angle sensor that detects the angle of rotation of the mast arm.

[0010] In a preferred embodiment, a second angle of rotation sensor is driven via the further gear, whereby redundancy in the measurement of the angle of rotation can be achieved, ie should a angle of rotation sensor fail or output measured values that deviate significantly from the first angle of rotation sensor, the control of the large manipulator can be transferred to an emergency program, for example, after evaluation of the measurement signals.

[0011] In a further preferred embodiment, the two sensors operate according to different measuring principles, which allows for further improvement in redundancy behavior because, for example, disturbances that may affect the signal of one angle sensor do not affect the other angle sensor. One angle sensor can be designed, for example, as an absolute value encoder, and the second angle sensor comprises an electrical cam switch mechanism in which the cams act as limit switches and define the end positions of certain working ranges of the mast arm.

[0012] In a further preferred embodiment, the additional gear, which can be arranged above or below the column pinion, but is preferably arranged below the column pinion, is made of a non-metallic material, for example plastic, preferably polyurethane, polyethylene, or a fiber composite material. Due to the large forces acting on the gear, the components of truck-mounted concrete pumps are generally made of metallic materials, particularly steel. However, significant weight and cost savings can be achieved with this gear if it is made of a lightweight plastic material, because only small forces need to be transmitted by this gear to drive the rotation angle sensors.

[0013] According to one variant of the invention, the large manipulator with a boom arm and a rotatable bearing of the boom arm comprises a gearwheel that is non-rotatably mounted at the lower end of the boom arm, a linear drive, and a rack that is horizontally displaceable by means of the linear drive, the teeth of which engage with the gearwheel, thereby converting the pushing movement of the rack into a rotary movement of the boom arm. The large manipulator is characterized by having at least one toothed belt that engages the boom arm and transmits the rotary movement of the boom arm to at least one rotation angle sensor that detects the rotation angle of the boom arm.

[0014] Advantageously, the mast arm has an additional gear arranged on the same axis as the first gear. The toothed belt meshes with the additional gear. This additional gear transmits the rotational movement of the mast arm via the toothed belt to at least one rotation angle sensor that detects the rotation angle of the mast arm.

[0015] In a preferred embodiment, the large manipulator has a second angle sensor. Ideally, the second angle sensor is connected to one of the gears via its own toothed belt. This allows for redundancy in the angle measurement. A belt break or slippage does not immediately lead to a failure of the angle measurement.

[0016] According to a further variant of the present invention, the large manipulator with a mast arm and a rotatable bearing of the mast arm comprises a gear that is arranged in a rotationally fixed manner at the lower end of the mast arm, a linear drive, a rack that is horizontally displaceable by means of the linear drive and whose teeth engage with the gear, whereby the pushing movement of the rack is converted into a rotary movement of the mast arm. The manipulator is characterized in that it has at least one cable, one of whose ends is arranged on a rotating column or the mast arm, and it has a displacement sensor that detects a change in the length of the cable during the rotary movement of the mast arm. The distance traveled by the cable is proportional to a rotation angle α, the angle through which the rotating column or the mast arm rotates. After calibration, the distance traveled by the cable can be used to measure the angle α. The cable is preferably attached to the circumference of the rotating column.

[0017] In a preferred embodiment, the large manipulator has two cables and two corresponding displacement sensors. This allows for redundancy in the measurement of the angle of rotation.

[0018] The displacement sensor is preferably a cable tension sensor. The cable tension sensor preferably has a cable drum with a spring mechanism. The cable tension sensor converts the change in length of the cable into a rotational movement. The displacement sensor can be mounted on the mast support.

[0019] According to a variant of the present invention, the rotation angle detection for a large manipulator with a linear drive, which sets the mast arm in a rotational movement via a rack, comprises means for detecting the position of the rack, from which the rotation angle of the mast arm is derived.

[0020] The means for detecting the position of the rack include, for example, a barcode attached to the rack and a barcode reader. The barcode reader is preferably mounted on the mast support. By reading a section of the barcode on the rack with the barcode reader, the position of the rack between the two linear drives can be determined, thus determining the angle of rotation of the mast arm.

[0021] Alternatively, the means for detecting the position of the rack may comprise at least one flow meter for the drive fluid driving the linear drive, e.g. hydraulic oil, whereby the position of the rack, and thus also the angle of rotation of the mast arm, is determined from the hydraulic oil flow.

[0022] According to an alternative embodiment of the invention, the means for detecting the position of the rack comprise a magnetostrictive length measuring system. A magnetostrictive length measuring system for a linear drive designed as a plunger-piston cylinder consists, for example, of a metallic lance mounted on the bottom of the hydraulic cylinder, which extends axially into the piston or rack. A ring magnet is located in the piston, through which the lance extends.

[0023] If a current pulse with a radial magnetic field is now sent through the lance, a torsional pulse is created from the collision of the lance's magnetic field with the magnetic field of the ring magnet. This torsional pulse travels as a structure-borne sound wave at a constant ultrasonic speed from the measuring point to the ends of the waveguide and is converted into an electrical pulse in a transducer system. Depending on how far the lance is inserted into the rack or piston, the travel time of the structure-borne sound wave changes. The position of the rack in the plunger piston cylinders can be derived from the travel time, and the angle of rotation of the mast arm can be derived from the position of the rack engaging the column pinion.

[0024] It should be noted that the features listed individually in the patent claims can also be combined with each other in any technologically reasonable manner and thus show further embodiments of the invention.

[0025] Exemplary embodiments of the invention are explained below with reference to the drawings. They show: Fig. 1 Side view of a large manipulator in supported state; Fig. 2 Top view of the large manipulator from Fig. 1; Fig. 3 Rotary drive of the mast arm of a large manipulator with rack and pinion drive; Fig. 4 Perspective view of a rotary drive of the mast arm according to a first variant of the invention; Fig. 5 Top view of the rotary drive according to the second variant of the invention in a first embodiment; Fig. 6 Top view of the rotary drive according to the second variant of the invention in a second embodiment; Fig. 7 Sectional view of the rotary drive according to a third variant of the invention; Fig. 8 Top view of the rotary drive according to the third variant.

[0026] Fig. 1 shows a large manipulator 2 designed as a truck-mounted concrete pump with a concrete pump 8 mounted on a truck chassis and a concrete feed hopper with a concrete switching valve 10. The concrete pump 8 pumps the concrete filled into the concrete feed hopper through the concrete delivery pipe 5 to the tip of the boom arm 4, where the concrete is transferred to the construction site, e.g. into a formwork, by means of an end hose (not shown).

[0027] The truck-mounted concrete pump 2 is supported by front supports 12 and rear supports 14 for pumping operation with the boom arm extended, so that the wheels of the truck-mounted concrete pump hang on the chassis of the truck-mounted concrete pump.

[0028] Two linear motors designed as plunger cylinders 18 ad are mounted on the mast bracket 6, whose function is related to the Fig. 3 will be explained in more detail.

[0029] In Fig. 2, the truck-mounted concrete pump 2 is shown with the supports not extended to the sides. This means that the boom arm 4 may only be rotated over a very limited angle, as shown by the arrow at the level of the concrete feed hopper 10, because otherwise there is a risk that the truck-mounted concrete pump 2 will tip over. Fig. In the scenario shown in Figure 2, for example, the boom arm can only be swivelled to the extent that maintenance or repair work on the concrete pump 8 is possible.

[0030] Fig. Figure 3 shows a horizontal section through the mast support 6 with four laterally arranged, horizontally aligned plunger piston cylinders 18a-d. Racks 20a,b with pistons 21a-d arranged at each end are arranged in the plunger piston cylinders 18a-d. The racks 20a,b are displaced horizontally in the plunger piston cylinders 18a-d by the introduction of hydraulic oil by means of the pistons 21a-d. The teeth of the racks 20a,b engage with the teeth of the column pinion 22, which is arranged at the lower end of the rotating column 16, causing the mast arm 4 to rotate.

[0031] In the Fig. Figure 3 shows four plunger cylinders 18a-d with two racks 20a, 20b. However, it is also possible to use only two plunger cylinders with a single rack, driving the column pinion 22 on only one side. This is simply a matter of dimensioning the plunger cylinders and the rack.

[0032] Fig. Figure 4 shows a perspective view of the mast support 6 with the rotating column 16 rotatably mounted therein, at the lower end of which the column pinion 22 is arranged. The four plunger piston cylinders 18a-d are arranged horizontally on the sides of the mast support 6, which cause the rotating column 16 to rotate by displacing the racks 20a,b.

[0033] On the underside of the rotating column 16, below the column pinion 22, a gear 24 is firmly connected to the rotating column 16. When the rotating column 16 is rotated by the plunger cylinders 18a-d via the racks 20a, 20b, the gear 24 also rotates. The rotational movement of the gear 24 is transmitted to the pinions 26a, b of the two rotation angle sensors 28 and 30. The two rotation angle sensors 28, 30 send their sensor signals, for example, to a mast control system, which calculates the rotation angle of the mast 4 from the sensor signals and, using the data on the machine's support status, limits the rotation angle of the mast if necessary to prevent the truck-mounted concrete pump from tipping over.

[0034] The two angle sensors 28 and 30 are necessary for redundancy in a truck-mounted concrete pump, as the failure of only one angle sensor can have serious consequences. To achieve even greater redundancy, the two angle sensors can operate according to different measuring principles. For example, one of the angle sensors can output an absolute angle value, while the other angle sensor is a limit value transmitter that supplies information about specific positions of the slewing gear to the control electronics via several parallel, offset cams.

[0035] For more precise angle determination, or angle determination with the highest possible resolution, the diameter of gear 24 is larger than the diameter of pinions 26a, 26b. Because gear 24 only has to transmit the small forces necessary for angle determination, it is made of a plastic material, preferably polyurethane (PUR) or polyethylene (PE), but can also be made of a fiber composite material. This results in low weight and low manufacturing costs.

[0036] Fig. Figure 5 shows the travel measurement on the racks 20a, 20b using barcodes 34a, 34b attached to the racks and barcode readers 32a, 32b. The barcode readers 32a, 32b are preferably mounted on the mast support and read a section of the barcodes 34a, 34b on the rack, for example, using a laser. By evaluating the detected section of the barcodes 34a, 34b, the position of the rack 20a, 20b between the plunger cylinders is determined, thus determining the angle of rotation of the mast arm. The barcodes 34a, 34b are preferably inscribed into the surface of the rack during production using a suitable process (e.g., etched or lasered) to ensure abrasion resistance, but can also be printed or glued onto the surfaces of the racks 20a, 20b.

[0037] Here, too, the second barcode reader serves as redundancy so that if one barcode reader fails or if the results of the barcode evaluation differ, the concrete pump control system can trigger appropriate measures.

[0038] Fig. Figure 6 shows the displacement measurement of the racks 20a, 20b with flow meters 40, 42, which determine the volume flow of the hydraulic fluid supplied to the plunger cylinders 18a, 18b, 18c, 18d by the controllable hydraulic pump 38, driven by a suitable drive 36. With the aid of suitable measuring electronics that evaluates the signals from the flow meters, the quantity of hydraulic oil in each of the plunger cylinders 18a, 18b, 18c, 18d is determined, thereby deriving the position of the piston rods designed as racks and ultimately determining the angle of rotation of the boom arm 2.

[0039] The invention has been described here in connection with a truck-mounted concrete pump with a boom arm mounted thereon, but it should also be pointed out that the invention is also applicable to concrete placing booms with a boom arm, which are also rotated by a linear drive 18.

[0040] Fig. Figure 7 shows a sectional view of the rotary drive according to a third variant of the invention. The large manipulator has a cable 46, one of whose ends is arranged on the rotating column 16 or on the mast arm 4. Furthermore, the large manipulator has a displacement sensor 44, which detects a change in the length of the cable 46 during the rotational movement of the mast arm 4. The displacement sensor 44 is preferably a cable tension sensor. The cable tension sensor preferably has a cable drum 48 with a spring mechanism. The change in the length of the cable 46 is converted into a rotational movement in the cable tension sensor. The displacement sensor 44 can be arranged on the mast support 6.

[0041] Fig. Figure 8 shows a top view of the rotary drive according to the third variant. The path traveled by the cable 46 is proportional to a rotation angle α, the angle by which the rotating column 16 or the mast arm 4 rotates. After calibration, the path traveled by the cable 46 can be used to measure the angle α. The cable 46 is preferably attached to the circumference of the rotating column 16.

[0042] In a preferred embodiment, the large manipulator can also have two cables 46 and, preferably, two corresponding displacement sensors 44. This allows for redundancy in the measurement of the angle of rotation. List of reference symbols 2 large manipulators, truck-mounted concrete pumps 4 Mast arm 5 Concrete delivery pipe 6 Mast trestle 7 Mast joint 8 concrete pump 10 feed hoppers with concrete switching valve 12 front support 14 rear support 16 Rotating column 18 Linear drive 18 ad plunger cylinder 20 a,b rack 21 ad piston 22 gear, column pinion 24 gear for angle measurement 26 a,b pinion angle sensors 28 first angle sensor 30 second angle sensor 32 a,b barcode readers 34 a,b Barcodes on racks 36 Hydraulic pump drive 38 controlled hydraulic pump 40 first volume measuring device 42 second volume measuring device 44 displacement sensor 46 rope 48 rope drum

Claims

[1] Large manipulator (2) with a mast arm (4) and a rotatable bearing of the mast arm (4), comprising: - a gear (22) which is arranged at the lower end of the mast arm (4) in a rotationally fixed manner, - a linear drive, (18) - a rack (20a, 20b) which is horizontally displaceable by means of the linear drive (18) and whose teeth engage with the gear (22), whereby the pushing movement of the rack (20a, 20b) is converted into a rotary movement of the mast arm (4), characterized by that the large manipulator has a further gear (24) which is arranged on the same axis as the first gear (22), wherein the further gear (24) transmits the rotational movement of the mast arm (4) to at least one rotation angle sensor (28) which detects the angle of rotation of the mast arm (4). [2] Large manipulator (2) according to claim 1, characterized bythat a further rotation angle sensor (30) is arranged on the further gear wheel (24), which also detects the rotation angle of the mast arm. [3] Large manipulator (2) according to claim 2, characterized by that the angle of rotation sensors (28,30) measure the angle of rotation according to different measuring principles. [4] Large manipulator (2) according to one of the preceding claims, characterized by that the further gear (24) is made of plastic or another lightweight material. [5] Large manipulator (2) with a mast arm (4) and a rotatable bearing of the mast arm (4), comprising: - a gear (22) which is arranged at the lower end of the mast arm (4) in a rotationally fixed manner, - a linear drive, (18) - a rack (20a, 20b) which is horizontally displaceable by means of the linear drive (18) and whose teeth engage with the gear (22), whereby the pushing movement of the rack (20a, 20b) is converted into a rotary movement of the mast arm (4), characterized by that the large manipulator has at least one toothed belt which engages the mast arm (4) and transmits the rotational movement of the mast arm (4) to at least one rotation angle sensor (28) which detects the rotation angle of the mast arm (4). [6] Large manipulator (2) with a mast arm (4) and a rotatable bearing of the mast arm (4), comprising: - a gear (22) which is arranged at the lower end of the mast arm (4) in a rotationally fixed manner, - a linear drive (18), - a rack (20a, 20b) which is horizontally displaceable by means of the linear drive (18) and whose teeth engage with the gear (22), whereby the pushing movement of the rack (20a, 20b) is converted into a rotary movement of the mast arm (4), characterized bythat the large manipulator has at least one cable (46) which is arranged with one of its ends on a rotating column (16) and that the large manipulator has a displacement sensor (44) which detects a change in the length of the cable (46) during the rotary movement of the mast arm (4). [7] Large manipulator according to one of the preceding claims, characterized by that the rack (20a,20b) is designed as a cylinder rod. [8] Large manipulator (2) according to one of the preceding claims, characterized by that the linear drive (18) is formed by at least one horizontally aligned plunger cylinder (18a, 18b, 18c, 18d). [9] Large manipulator (2) according to the preceding claim, characterized by that the linear drive (18) comprises two plunger cylinders (18a, 18b, 18c, 18d) running along the same horizontal axis and facing each other. [10] Large manipulator (2) with a mast arm (4) and a rotatable bearing of the mast arm (4), comprising: - a gear (22) which is arranged at the lower end of the mast arm (4) in a rotationally fixed manner, - a linear drive (18), - a rack (20a, 20b) which is horizontally displaceable by means of the linear drive (18) and whose teeth engage with the gear (22), whereby the pushing movement of the rack (20a, 20b) is converted into a rotary movement of the mast arm (4), characterized by Position detection means (32, 34, 40,42) for detecting the position of the rack (20a, 20b), from which the angle of rotation of the mast arm (2) is derived. [11] Large manipulator (2) according to the preceding claim, characterized by that the rack (20a, 20b) is designed as a cylinder rod. [12] Large manipulator (2) according to one of the preceding claims 10 or 11, characterized bythat the linear drive (18) is formed by at least one horizontally aligned plunger cylinder (18a, 18b, 18c, 18d). [13] Large manipulator (2) according to the preceding claim, characterized by that the linear drive (18) comprises two plunger cylinders (18a, 18b, 18c, 18d) running along the same horizontal axis and facing each other. [14] Large manipulator (2) according to one of claims 10 to 13, characterized by that the position detection means comprise a bar code (34a, 34b) on the rack (20a, 20b) and a bar code reader (32a, 32b). [15] Large manipulator (2) according to one of claims 10 to 13, characterized by that the position detection means comprise at least one volume measuring device (40, 42) which detects the flow of the drive fluid of the plunger cylinder (20a, 20b, 20c, 20d). [16] Large manipulator (2) according to one of claims 10 to 13, characterized bythat the position detection means comprise at least one magnetostrictive displacement sensor which detects the position of the rack (20a, 20b).

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