Abstract
A road finisher is provided for producing a paving layer on a subgrade on which the road finisher is movable along a paving direction during a paving run. The road finisher is adapted to use distance measurements to the subgrade, which can be provided to a leveling system of the road finisher, equally as measured values for determining the thickness of a layer. A respective method for determining the layer thickness is provided.
Claims
1. A road finisher for producing a paving layer on a subgrade on which the road finisher is movable along a paving direction during a paving run, the road finisher comprising a height-adjustable paving screed for producing the paving layer and a leveling system configured to control a height of the paving screed, in order to compensate for unevenness of the subgrade, wherein the leveling system comprises a first measuring device comprising at least a first sensor unit configured to contactlessly measure at least a first distance to a surface of the subgrade during the paving run and at least one second sensor unit configured to contactlessly measure at least a second distance to a surface of the paving layer produced on the subgrade during the paving run, wherein the road finisher is configured to determine a reference level based on the first and second distances, on the basis of which a leveling actual value can be provided to the leveling system for controlling the height of the paving screed, and wherein the road finisher is configured to further determine a layer thickness of the paving layer produced on the subgrade based on the first distance measured by means of the first sensor unit and on the second distance measured by means of the second sensor unit.
2. The road finisher according to claim 1, wherein the road finisher is configured to determine the layer thickness solely by means of hardware components used on the road finisher for the leveling system.
3. The road finisher according to claim 1, wherein the distances measured by means of the sensor units of the measuring device can be used both as a basis for an automatic leveling of the paving screed and for a layer thickness measuring function.
4. The road finisher according to claim 3, wherein the automatic leveling can be addressed on the road finisher separately from or together with the layer thickness measuring function.
5. The road finisher according to claim 1 further comprising a common control device for the leveling system and the determination of the layer thickness, wherein the control device is integrally mounted on a portion of the road finisher.
6. The finisher according to claim 5, wherein the control device is configured to adjust, based on the actual leveling value, a position of leveling cylinders attached to the paving screed at front traction points for varying the layer thickness.
7. The road finisher according to claim 1, wherein the measuring device comprises a supporting structure for the first and second sensor units extending along the paving direction, on which supporting structure the first sensor unit is positioned in front of the paving screed and the second sensor unit is positioned behind the paving screed in the paving direction.
8. The road finisher according to claim 1, wherein the measuring device comprises a third sensor unit and a fourth sensor unit for measuring respective distances to the surface of the subgrade, the third and fourth sensor units being positioned in the paving direction in front of the paving screed on the supporting structure, and wherein the first, second, third and fourth sensor units are positioned in the paving direction at a multiple of a predetermined distance from one another on the supporting structure of the measuring device.
9. The road finisher according to claim 1 further comprising at least one distance measuring means, wherein the at least one distance measuring means includes a satellite-based distance measuring unit and a mechanical distance measuring unit, or the at least one distance measuring means includes at least one optical distance measuring unit.
10. The road finisher according to claim 1, wherein the sensor units each comprise an ultrasonic multi-sensor having a plurality of sensor cells arranged side by side, each configured to perform distance measurements.
11. The road finisher according to claim 10, wherein the road finisher is configured to take into account the distance measurements detected by the sensor units by means of the respective sensor cells formed on the sensor units, the distance measurements being tolerant with respect to a nominal distance measurement value which is variably adjustable for the respective sensor units, when leveling the paving screed and/or when determining the layer thickness.
12. The road finisher according to claim 1, wherein a currently determined layer thickness or a layer thickness averaged over a period of time therefrom can be provided to the leveling system for controlling the height of the paving screed as a further leveling actual value.
13. The finisher according to claim 1, wherein the leveling system comprises a second measuring device, the first measuring device being arranged in the paving direction on one side of the road finisher and the second measuring device being arranged in the paving direction on an opposite side of the road finisher.
14. The road finisher according to claim 1, wherein the leveling system is functionally connected to a memory unit, on which, for documentation purposes, measured layer thickness values detected during the paving run can be stored and/or the detected layer thickness can be displayed visually at an external operating stand of the road finisher by means of a display unit attached thereto and/or the road finisher has a transmission unit by means of which the determined layer thickness values can be transmitted to an external device.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the disclosure are explained in more detail with reference to the following Figures.
(2) FIG. 1 shows a road finisher for producing a paving layer on a subgrade;
(3) FIG. 2 shows a road finisher with a laterally arranged, elongate measuring device for establishing a virtual reference level for an automatic leveling;
(4) FIG. 3 shows a schematic view of a measuring device according to FIG. 2 with four sensor units;
(5) FIG. 4 shows a schematic view of a measuring principle of the sensor units shown in FIG. 3 directed in the paving direction in front of the paving screed towards the subgrade; and
(6) FIG. 5 shows schematic view of the leveling system used on the road finisher with integrated layer thickness measuring function.
(7) Technical features are marked with the same reference numerals throughout the Figures.
DETAILED DESCRIPTION
(8) FIG. 1 shows a road finisher 1 producing a paving layer 2 on a subgrade 3 on which the road finisher 1 is moving along a paving direction R during a paving run. The road finisher 1 is equipped with a height-adjustable paving screed 4 for (pre)compacting the paving layer 2. The paving screed 4 is attached to a screed bar 5, which is connected to a leveling cylinder 7 of the road finisher 1 at a front traction point 6. The screed bar 5 serves as a lever to convert a variation of a leveling cylinder position into a variation of an angle of attack of the paving screed 4, in particular to compensate for unevenness 8 in the subgrade 3.
(9) FIG. 2 shows the road finisher 1 during the paving run. In FIG. 2, the paving screed 4 is configured as a telescoping screed. A first measuring device 9 is located at the screed bar 5. The measuring device 9 comprises a first sensor unit 10, which is configured to contactlessly measure a first distance A1 to a surface O1 of the subgrade 3, for example by means of ultrasound, during the paving run. The measuring device 9 also has a second sensor unit 11 which is configured to contactlessly measure a second distance A2 to a surface O2 of the paving layer 2 produced on the subgrade 3, for example by means of ultrasound, during the paving run.
(10) Using the first sensor unit 10 and the second sensor unit 11, the relative height of the subgrade 3 and the paved paving layer 2 is scanned in FIG. 2 in order to determine a reference level 12 (see FIG. 4) from these measurement results. Based on this, a leveling actual value 13a, 13b is generated as a control variable which can be used in the leveling system 14 to control the level of the paving screed 4 (see FIG. 5).
(11) According to FIG. 2, the measuring device 9 comprises a supporting structure 15 which extends over several meters in the paving direction R to the side of the road finisher 1. The first sensor unit 10 is located on the supporting structure 15 in front of the paving screed 4 in paving direction R. The second sensor unit 11 is attached to the supporting structure 15 behind the paving screed 4 in paving direction R. FIG. 2 also shows that a further, third sensor unit 16 is mounted on the supporting structure 15 at a short distance in front of the paving screed 4 in paving direction R.
(12) FIG. 2 also shows an external control station 17 attached to the paving screed 4 by means of a sideshift 18. On the external control station 17, distance measurements of the respective sensor units 10, 11, 16 (including the fourth sensor unit 25 shown in FIG. 3) can be monitored and controlled by an input/display unit 19 provided on the external control station. In case the reference level 12 based on the height measurements does not correspond to a target reference level, this can be displayed on the input/display unit 19. An operator can then use the input/display unit 19 to manually change a height of the paving screed 4 on the left and/or right side of the road finisher, for instance, to compensate for detected unevenness 8 in the subgrade. An automatic leveling system can be used as a supplement or alternative to control the height of the paving screed 4.
(13) FIG. 2 also shows that road finisher 1 has a satellite-based distance measuring unit 20 (e.g., a GNSS, DGPS, DGNSS and/or RTK unit) on a roof structure 24. The satellite-based distance measuring unit 20 can be part of a satellite-based navigation system of the road finisher 1 and is adapted to carry out a GPS measurement for determining the position of the road finisher 1. In addition, the road finisher 1 shown in FIG. 2 has a mechanical distance measuring unit 22 mounted on the drive 21 of the road finisher 1. The mechanical distance measuring unit 22 is configured, for example, as a podometer device to determine a distance travelled by the road finisher 1 during, the paving run. On the road finisher 1 of FIG. 2, the satellite-based distance measuring unit 20 and the mechanical distance measuring unit 22 are functionally linked to each other in order to provide, as an integral distance measuring means, a highly accurate measurement of the distance travelled by the road finisher 1 during the paving run, in particular for the purpose of determining the thickness of the paving layers.
(14) Alternatively, the distance measuring means formed by a combination of the satellite-based and mechanical distance measuring units 20, 22 could also consist of an optical distance measuring unit 23, which is arranged in particular on a chassis of the road finisher 1.
(15) FIG. 3 shows a schematic view of measuring device 9 with a total of four sensor units 10, 11, 16, 25 arranged thereon. In paving direction R, the second sensor unit 11 is arranged behind the paving screed 4 on the supporting structure 15 of the measuring device 9 to measure the second distance A2 to the surface O2 of the paved paving layer 2. In paving, direction R, three sensor units 10, 16, 25 are positioned in front of the paving screed 4 to measure the height to the subgrade 3. The first sensor unit 10 is positioned at the very front of the supporting structure 15 of the measuring device 9. The third sensor unit 16 and a further, fourth sensor unit 25 are positioned behind it in paving direction R of the paving screed in order to measure a distance A3, A4 to the surface O1 of the subgrade 3. The frontmost, first sensor unit 10 is distanced by a distance 1 from the fourth sensor unit 25 positioned behind it in the paving direction R. There is also a distance 1 between the fourth sensor unit 25 and the third sensor unit 16 positioned further behind it on the supporting structure 15 in the paving direction R.
(16) Furthermore, FIG. 3 shows that the second sensor unit 11, which is positioned at the end of the supporting structure 15, is positioned at twice the distance 1 from the third sensor unit 16, which is positioned at the front in the paving direction R. The distance between the respective sensor units 10, 11, 16, 25 on the supporting structure 15 of measuring device 9 can be variably adjusted, which is shown schematically by means of an arrow 26 in the area of the third sensor unit 16.
(17) FIG. 4 shows a schematic view of the measuring principle of the sensor units 10, 16, 25 used on the measuring device 9. FIG. 4 shows an example of the sensor units 10, 16 and 25 positioned on the supporting structure 15 of the measuring device 9 in the paving direction R in front of the paving screed 4.
(18) The first, third and fourth sensor units 10, 16, 25 (as well as the second sensor unit 11 from FIG. 3 not shown in FIG. 4) are each designed as ultrasonic multi-sensor 27a, 27b, 27c according to FIG. 4. The respective ultrasonic multi-sensors 27a, 27b, 27c have a plurality of sensor cells 28 arranged next to each other. In FIG. 4, the respective ultrasonic multi-sensors 27a, 27b, 27c each have five sensor cells 28 arranged in a row. The respective distances to the subgrade 3, measured by means of the sensor cells 28, can be used to determine the virtual reference level 12 shown FIG. 4.
(19) FIG. 4 shows schematically that only three height measurements detected at the respective ultrasonic multi-sensors 27a, 27b, 27c are used to form the reference level 12. The measured values detected at the respective sensor units 10, 16, 25, which represent the largest deviations from a stored or calculated reference, are ignored and are not included in the calculation of the reference level. The reference level 12 can be established, for example, by averaging the measured values detected and taken into account by the respective sensor units 10, 16, 25.
(20) Based on the detected reference level 12, the leveling system 14 shown in FIG. 5 can carry out an automatic leveling operation 29 on respective leveling cylinders 7a, 7b attached to the left and right of the road finisher 1 to automatically control a level of the paving screed 4, especially for compensating for unevenness 8 in the subgrade 3.
(21) The leveling system 14 shown in FIG. 5 is installed integrally on the road finisher 1. The leveling system 14 comprises a central control unit 30 which is continuously fed with distance measurements from the respective sensor units 10, 11, 16, 25. The control device 30 is configured to determine the reference level 12 and, based on this, to generate actual leveling values 13a, 13b for the respective leveling cylinders 7a, 7b to control them in order to vary a position of the leveling cylinders 7a, 7b. Furthermore, the central control device 30 is configured to determine a layer thickness 31 (see also FIGS. 1 and 3) based on the respective detected distances A1, A2, A3, A4 of the sensor units 10, 11, 16, 26.
(22) FIG. 5 shows that the distance measurements A1, A2, A3, A4 detected by the sensor units 10, 11, 16, 25 for the leveling system 14 for producing the reference level 12 are also used to determine the layer thickness 31 of the produced paving layer 2.
(23) The leveling system 14 in FIG. 5 also has a transmission device 32 by means of which the calculated layer thickness values can be transmitted to an external device (not shown).
(24) Furthermore, FIG. 5 shows that the leveling system 14 can be controlled by means of a functionally connected control 33. The control 33 can, for example, be an integral part of the external control station 17, especially the input unit 19 positioned there. Finally, FIG. 5 shows that the leveling system 14 has a memory unit 34 which, according to FIG. 5, can be designed, for example, as an integral part of the control unit 30, in particular to store detected layer thickness measurements for documentation purposes.
